From jltran at worldnet.att.net Sun Nov 1 01:20:32 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sat, 31 Oct 2009 20:20:32 -0500 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: Message-ID: <8657E2BDDB9143B79B1F4B9ABE83639F@S0028384766> Said, Thanks for the reply. This is certainly a starting point. A schematic would be wonderful. I have looked and have not found one yet. The units both provide about 4.5 VDC to the center pin when any port is connected to my Tbolt. However, the signal amplitude, as measured by TBoltMon, is essentially non existent on the 4 way splitter and divided by at least 2 on the 2 way splitter. Therefore, I suspect the amplifier is dead. Did not know about the voltage regulator. Will open one and get to work. Thanks, Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of SAIDJACK at aol.com Sent: Saturday, October 31, 2009 5:46 PM To: time-nuts at febo.com Subject: Re: [time-nuts] HP/Symmetricom 58535A and 58536A Hi Joe, these are very simple circuits, basically just a voltage regulator from LT, and an Agilent L1 amplifier MMIC, and a number of SAW/Cavity filters, one for each output. Depending on what is wrong (the voltage regulator, or the MMIC) you can probably replace these two with a host of compatible parts from Mini-circuits etc. There are also a resistive splitter (made of SMT resistors) and GPS L1 filters on the outputs. If I remember correctly the voltage regulator prepares a voltage of about 3V for the MMIC, so you can probably use various 3V or 3.3V regulators to replace that one if it's bad. The MMIC is a low-noise ~20dB gain block. If the gain block is bad, you can probably use the Mini Circuits ERA-3+ amp as a drop-in replacement, even though it's NF could be lower than 2.6dB. If the SAW/cavity filters are bad, I would just remove it and bridge it with a wire. It's not really needed, today's GPS receivers have these built-in already. Removing it would probably increase the output sensitivity by a couple of dB. Lastly, they either had the option to be powered by input 1 (via 5V from the Coax) or via an SMC connector. Most units receive power only from the SMC. You can also provide power into the unit(!) from the Antenna connector (3.5V to 5.5V) - that actually works well too. It won't work if you do not properly provide power to the unit. You can test this by measuring the center pin of the Antenna connector, there should be 5V on it. If there isn't, then the amp does not get power properly. Lastly, if you want to modify the unit to receive power from output port 1, then just add a small inductor (say 15nH to 33nH) to the footprint for it right at the output connector. bye, Said In a message dated 10/31/2009 15:27:47 Pacific Daylight Time, jltran at worldnet.att.net writes: Anyone with manuals or schematics for these units? Anyone with any experience repairing them? Thanks in advance. Joe _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From john at pcsupportsolutions.com Sun Nov 1 01:35:14 2009 From: john at pcsupportsolutions.com (John Allen) Date: Sat, 31 Oct 2009 21:35:14 -0400 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: <0CC7CBD535E54410B33A96132186B30F@S0028384766> References: <0CC7CBD535E54410B33A96132186B30F@S0028384766> Message-ID: <49B7CB1F2B674AFAB220724A67400E45@DBTOA000> Hi Joe - I have the "Information Note" that comes with new 58535A units. I wish I could scan and email it, but no scanner right now. The most useful info is the specs - below. BW +/- 10 MHz -3 db Gain 0 +/- 3 db NF 5 db typ. VSWR 1.2 input typ. 1.6 typ output both at L1 Isolation -30 db at L1, -54 db 40 Mhz from L1 DC Power +4.5 to +13 VDC Current 23-48 ma depending on Voltage. AC Input level - Max -25 dbm, damage level +17 dbm at L1 (Mech and Env omitted) John -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of J. L. Trantham Sent: Saturday, October 31, 2009 6:27 PM To: time-nuts at febo.com Subject: [time-nuts] HP/Symmetricom 58535A and 58536A Anyone with manuals or schematics for these units? Anyone with any experience repairing them? Thanks in advance. Joe From jltran at worldnet.att.net Sun Nov 1 01:52:11 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sat, 31 Oct 2009 20:52:11 -0500 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: <49B7CB1F2B674AFAB220724A67400E45@DBTOA000> Message-ID: <2EB3396A5BBC4B1B861B03E70D441DDE@S0028384766> John, Thanks for the effort. I have the info sheet. I am looking for a service manual ideally but likely will not find it though I thought I would ask. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of John Allen Sent: Saturday, October 31, 2009 8:35 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] HP/Symmetricom 58535A and 58536A Hi Joe - I have the "Information Note" that comes with new 58535A units. I wish I could scan and email it, but no scanner right now. The most useful info is the specs - below. BW +/- 10 MHz -3 db Gain 0 +/- 3 db NF 5 db typ. VSWR 1.2 input typ. 1.6 typ output both at L1 Isolation -30 db at L1, -54 db 40 Mhz from L1 DC Power +4.5 to +13 VDC Current 23-48 ma depending on Voltage. AC Input level - Max -25 dbm, damage level +17 dbm at L1 (Mech and Env omitted) John -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of J. L. Trantham Sent: Saturday, October 31, 2009 6:27 PM To: time-nuts at febo.com Subject: [time-nuts] HP/Symmetricom 58535A and 58536A Anyone with manuals or schematics for these units? Anyone with any experience repairing them? Thanks in advance. Joe _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From SAIDJACK at aol.com Sun Nov 1 03:20:16 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sat, 31 Oct 2009 23:20:16 EDT Subject: [time-nuts] HP/Symmetricom 58535A and 58536A Message-ID: Hi Joe, I have the same problem with my Thunderbolt even though my splitter works well. Not sure why. This is especially so if I cascade the Agilent unit with a passive splitter, I can never get the Thunderbolt to lock up. I think the added noise of the Amp may play funny with the Thunderbolt's receiver, and there may not be anything wrong with your splitter. M12M's and uBlox receiver's don't have a problem at all, even if two units are cascaded. They do start to have issues with three splitters in series. Do you have another receiver you can try? In terms of schematics, it's really straight forward, see the Mini-circuits website for sample schematics for the ERA part, the agilent unit has pretty much the same setup. The amp is followed by a resistive splitter, and possibly a resistive attenuator (on the 2-port version). Then a cavity filter, then the N-Connector, very simple, not much that can go wrong. bye, Said In a message dated 10/31/2009 18:21:16 Pacific Daylight Time, jltran at worldnet.att.net writes: Said, Thanks for the reply. This is certainly a starting point. A schematic would be wonderful. I have looked and have not found one yet. The units both provide about 4.5 VDC to the center pin when any port is connected to my Tbolt. However, the signal amplitude, as measured by TBoltMon, is essentially non existent on the 4 way splitter and divided by at least 2 on the 2 way splitter. Therefore, I suspect the amplifier is dead. Did not know about the voltage regulator. Will open one and get to work. Thanks, Joe From magnus at rubidium.dyndns.org Sun Nov 1 11:18:47 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 01 Nov 2009 12:18:47 +0100 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: References: Message-ID: <4AED6E97.8030804@rubidium.dyndns.org> SAIDJACK at aol.com wrote: > Hi Joe, > > I have the same problem with my Thunderbolt even though my splitter works > well. Not sure why. This is especially so if I cascade the Agilent unit > with a passive splitter, I can never get the Thunderbolt to lock up. > > I think the added noise of the Amp may play funny with the Thunderbolt's > receiver, and there may not be anything wrong with your splitter. > > M12M's and uBlox receiver's don't have a problem at all, even if two units > are cascaded. They do start to have issues with three splitters in series. > > Do you have another receiver you can try? > > In terms of schematics, it's really straight forward, see the Mini-circuits > website for sample schematics for the ERA part, the agilent unit has > pretty much the same setup. > > The amp is followed by a resistive splitter, and possibly a resistive > attenuator (on the 2-port version). Then a cavity filter, then the N-Connector, > very simple, not much that can go wrong. They do have DC load on the non-DC-thru ports. Check the open/short status on the thunderbolt. It's very easy to see with the Thunderbolt monitor program. Cheers, Magnus From bg at lysator.liu.se Sun Nov 1 12:02:56 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 1 Nov 2009 13:02:56 +0100 (CET) Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: References: Message-ID: <64653.87.227.52.225.1257076976.squirrel@webmail.lysator.liu.se> Hi Said, > I think the added noise of the Amp may play funny with the Thunderbolt's > receiver, and there may not be anything wrong with your splitter. > > M12M's and uBlox receiver's don't have a problem at all, even if two units > are cascaded. They do start to have issues with three splitters in series. Did you check that you have enough signal power for the Tbolt, when cascading (passive) splitters? -- Bj?rn From magnus at rubidium.dyndns.org Sun Nov 1 12:28:00 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 01 Nov 2009 13:28:00 +0100 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: <64653.87.227.52.225.1257076976.squirrel@webmail.lysator.liu.se> References: <64653.87.227.52.225.1257076976.squirrel@webmail.lysator.liu.se> Message-ID: <4AED7ED0.6030803@rubidium.dyndns.org> bg at lysator.liu.se wrote: > Hi Said, > >> I think the added noise of the Amp may play funny with the Thunderbolt's >> receiver, and there may not be anything wrong with your splitter. >> >> M12M's and uBlox receiver's don't have a problem at all, even if two units >> are cascaded. They do start to have issues with three splitters in series. > > Did you check that you have enough signal power for the Tbolt, when > cascading (passive) splitters? If cascading active splitters, the gain should be about 0 dB, but the S/N degrades. If I recall correctly, the HP/Agilent/Symmetricom range of splitters are all active. When running multiple splitters, adding an LNA to raise the level such that S/N degradation does not suffer as much is probably wise. Cheers, Magnus From jltran at worldnet.att.net Sun Nov 1 13:36:31 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sun, 1 Nov 2009 07:36:31 -0600 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: Message-ID: <62D4DE9ACF26404299738AD2A933DD40@S0028384766> Said, Interesting thought. I had not considered the TBolt to be a source of a problem. I also have two HP 58517A 8 way splitters, one that gets it's DC for the antenna through an SMB connector and one that gets it's DC from port 1. They seem to work fine with the TBolt. I also have a Symmetricom 090-58537-01 4 way splitter and it works fine with the TBolt as well. By this, I mean place the splitter between the TBolt and the antenna with nothing else connected. When I do this with the 58535A or 58536A, signal amplitudes, as noted on TBoltMon, are divided in two with the 2 way splitter and non existent with the 4 way splitter. I fired up my Z3816A, hooked it directly to the antenna and all was fine with good signal amplitudes as noted on SatStat. I then put the splitter in the circuit and, again, all was fine. I then hooked up the TBolt to another port of the splitter and, now, it too is fine. Seems it is all OK as long as the Z3816A is connected. I tried substituting a 50 ohm load on the ports but the TBolt problem came back. Might this be insufficient current for the amplifier and antenna from the TBolt? The 'Antenna Open' and 'Antenna Short' indications on TBoltMon are fine no matter how or what is connected. With the TBolt connected, I get about 4.5 VDC to the antenna from the splitter. I forgot to measure with the Z3816A connected. Thanks for the insight. My formerly thought dead splitters are, in fact, fine. I'll have to try adding an external supply to the splitter and see if that fixes the problem. Then, again, if just using the TBolt alone, why have a splitter? I guess the answer is that it is nice to have an easily available connection for other projects. Thanks again everyone for all the help. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of SAIDJACK at aol.com Sent: Saturday, October 31, 2009 10:20 PM To: time-nuts at febo.com Subject: Re: [time-nuts] HP/Symmetricom 58535A and 58536A Hi Joe, I have the same problem with my Thunderbolt even though my splitter works well. Not sure why. This is especially so if I cascade the Agilent unit with a passive splitter, I can never get the Thunderbolt to lock up. I think the added noise of the Amp may play funny with the Thunderbolt's receiver, and there may not be anything wrong with your splitter. M12M's and uBlox receiver's don't have a problem at all, even if two units are cascaded. They do start to have issues with three splitters in series. Do you have another receiver you can try? In terms of schematics, it's really straight forward, see the Mini-circuits website for sample schematics for the ERA part, the agilent unit has pretty much the same setup. The amp is followed by a resistive splitter, and possibly a resistive attenuator (on the 2-port version). Then a cavity filter, then the N-Connector, very simple, not much that can go wrong. bye, Said In a message dated 10/31/2009 18:21:16 Pacific Daylight Time, jltran at worldnet.att.net writes: Said, Thanks for the reply. This is certainly a starting point. A schematic would be wonderful. I have looked and have not found one yet. The units both provide about 4.5 VDC to the center pin when any port is connected to my Tbolt. However, the signal amplitude, as measured by TBoltMon, is essentially non existent on the 4 way splitter and divided by at least 2 on the 2 way splitter. Therefore, I suspect the amplifier is dead. Did not know about the voltage regulator. Will open one and get to work. Thanks, Joe _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From glennmaillist at bellsouth.net Sun Nov 1 22:51:24 2009 From: glennmaillist at bellsouth.net (Glenn Little WB4UIV) Date: Sun, 01 Nov 2009 17:51:24 -0500 Subject: [time-nuts] WWV Clock Message-ID: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> My WWV clock at home and the master clock at the TV station that I am engineer for did not update to EST from EDT. Did anyone else see their WWV clock not change time for DST? Thanks 73 Glenn WB4UIV From jpawlan at pawlan.com Sun Nov 1 22:58:04 2009 From: jpawlan at pawlan.com (Jeffrey Pawlan) Date: Sun, 1 Nov 2009 14:58:04 -0800 (PST) Subject: [time-nuts] WWV Clock In-Reply-To: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> References: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> Message-ID: My clock changed. I am in Calif. 73, Jeffrey Pawlan WA6KBL From msa at latt.net Sun Nov 1 23:26:54 2009 From: msa at latt.net (Majdi S. Abbas) Date: Sun, 1 Nov 2009 16:26:54 -0700 Subject: [time-nuts] WWV Clock In-Reply-To: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> References: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> Message-ID: <20091101232654.GB69624@puck.nether.net> On Sun, Nov 01, 2009 at 05:51:24PM -0500, Glenn Little WB4UIV wrote: > My WWV clock at home and the master clock at the TV station that I > am engineer for did not update to EST from EDT. > Did anyone else see their WWV clock not change time for DST? WWVB does have a bit that accounts for it, but most of those clocks just try to update once a day, and if they take a single bit error in the minute or two they check, they'll miss it. Also, many of them don't truly implement the DST mechanism; but relied on an internal calendar that told them when it would be due, and otherwise tend to disregard that bit. Move to Arizona, it worked for me ;) I no lonver have to play DST games, and it's quite refreshing. 73, Majdi, N0RMZ From jgray at zianet.com Sun Nov 1 23:44:20 2009 From: jgray at zianet.com (Joseph Gray) Date: Sun, 1 Nov 2009 16:44:20 -0700 Subject: [time-nuts] WWV Clock In-Reply-To: <20091101232654.GB69624@puck.nether.net> References: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> <20091101232654.GB69624@puck.nether.net> Message-ID: I have two inexpensive WWVB clocks and one updated correctly, the other didn't. Since they are identical models, I have to assume that one of them just missed the transmission. As for moving to AZ, I like that idea. I'm next door in NM and I never have liked the idea of DST. Joe KA5ZEC On Sun, Nov 1, 2009 at 4:26 PM, Majdi S. Abbas wrote: > On Sun, Nov 01, 2009 at 05:51:24PM -0500, Glenn Little WB4UIV wrote: >> My WWV clock at home and the master clock at the TV station that I >> am engineer for did not update to EST from EDT. >> Did anyone else see their WWV clock not change time for DST? > > ? ? ? ?WWVB does have a bit that accounts for it, but most of those > clocks just try to update once a day, and if they take a single bit > error in the minute or two they check, they'll miss it. > > ? ? ? ?Also, many of them don't truly implement the DST mechanism; > but relied on an internal calendar that told them when it would be > due, and otherwise tend to disregard that bit. > > ? ? ? ?Move to Arizona, it worked for me ;) ?I no lonver have to > play DST games, and it's quite refreshing. > > ? ? ? ?73, > > ? ? ? ?Majdi, N0RMZ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jim77742 at gmail.com Mon Nov 2 03:02:44 2009 From: jim77742 at gmail.com (Jim Palfreyman) Date: Mon, 2 Nov 2009 14:02:44 +1100 Subject: [time-nuts] WWV Clock In-Reply-To: References: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> <20091101232654.GB69624@puck.nether.net> Message-ID: It depends on where you live. If your latitude is 30 deg or greater it's fantastic. But I concede in the tropics it's not that useful. It's divided us here in Australia because we cover such a large range of latitudes. I'd presume it's the same in the US. At -43 deg S I wouldn't be without it - makes summer so much more enjoyable. Jim 2009/11/2 Joseph Gray : > As for moving to AZ, I like that idea. I'm next door in NM and I never > have liked the idea of DST. > > Joe > KA5ZEC From didier at cox.net Mon Nov 2 03:41:07 2009 From: didier at cox.net (Didier Juges) Date: Sun, 1 Nov 2009 21:41:07 -0600 Subject: [time-nuts] WWV Clock In-Reply-To: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> References: <6.2.3.4.2.20091101174922.03e93880@mail.bellsouth.net> Message-ID: For the first time in a while, both my WWV clocks updated right on time this year!!! I am in North-West Florida, where WWV signals are not overpowering. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Glenn Little WB4UIV > Sent: Sunday, November 01, 2009 4:51 PM > To: Time-Nuts list > Subject: [time-nuts] WWV Clock > > My WWV clock at home and the master clock at the TV station > that I am engineer for did not update to EST from EDT. > Did anyone else see their WWV clock not change time for DST? > > Thanks > 73 > Glenn > WB4UIV > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From REMartinson at rcn.com Mon Nov 2 03:53:43 2009 From: REMartinson at rcn.com (Bob Martinson) Date: Sun, 1 Nov 2009 22:53:43 -0500 Subject: [time-nuts] WWV Clock In-Reply-To: Message-ID: All 4 of mine did for the first time too!!! Bob, K1REM Waltham, MA -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of Didier Juges Sent: Sunday, November 01, 2009 10:41 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] WWV Clock For the first time in a while, both my WWV clocks updated right on time this year!!! I am in North-West Florida, where WWV signals are not overpowering. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Glenn Little WB4UIV > Sent: Sunday, November 01, 2009 4:51 PM > To: Time-Nuts list > Subject: [time-nuts] WWV Clock > > My WWV clock at home and the master clock at the TV station > that I am engineer for did not update to EST from EDT. > Did anyone else see their WWV clock not change time for DST? > > Thanks > 73 > Glenn > WB4UIV > > > From holrum at hotmail.com Mon Nov 2 03:56:26 2009 From: holrum at hotmail.com (Mark Sims) Date: Mon, 2 Nov 2009 03:56:26 +0000 Subject: [time-nuts] WWV Clock In-Reply-To: References: Message-ID: I just spent a considerable amount of effort teaching the Good Lady Heather about the subtle wonders of daylight savings time around the world... ?including the wacky backwards spinning universe down under. ? Hopefully even made it politician proof... ?when your local idiot politicians change the rules on a whim, ?you can specify your new DST rules in a rather clean manner. ------------ It's divided us here in Australia because we cover such a large range of latitudes. I'd presume it's the same in the US. At -43 deg S I wouldn't be without it - makes summer so much more enjoyable. _________________________________________________________________ New Windows 7: Find the right PC for you. http://www.microsoft.com/windows/pc-scout/default.aspx?CBID=wl&ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_pcscout:112009 From biwa at att.net Mon Nov 2 04:18:00 2009 From: biwa at att.net (Burt I. Weiner) Date: Sun, 01 Nov 2009 20:18:00 -0800 Subject: [time-nuts] WWVB Clock didn't change... In-Reply-To: References: Message-ID: <7.0.0.16.2.20091101200852.0391db90@att.net> It's not necessarily a sign of a problem. In many WWVB clocks this is intentional. I know of one radio station that had one controlling an automation system and it did change, 3 hours early! The station was in CA and it changed at 9 PM the night before (the eve of the great change). I have a home type that had switched by this morning but my Spectracom 8170 had not. It requires a change in the zone-hour-offset switch in the back. This is safer than having it switch at a time when it could cause some embarrassment. Your's may have the same requirement. Burt, K6OQK At 07:41 PM 11/1/2009, time-nuts-request at febo.com wrote >Date: Sun, 1 Nov 2009 16:26:54 -0700 >From: "Majdi S. Abbas" >Subject: Re: [time-nuts] WWV Clock >To: Discussion of precise time and frequency measurement > >Message-ID: <20091101232654.GB69624 at puck.nether.net> >Content-Type: text/plain; charset=us-ascii > >On Sun, Nov 01, 2009 at 05:51:24PM -0500, Glenn Little WB4UIV wrote: > > My WWV clock at home and the master clock at the TV station that I > > am engineer for did not update to EST from EDT. > > Did anyone else see their WWV clock not change time for DST? > > WWVB does have a bit that accounts for it, but most of those >clocks just try to update once a day, and if they take a single bit >error in the minute or two they check, they'll miss it. > > Also, many of them don't truly implement the DST mechanism; >but relied on an internal calendar that told them when it would be >due, and otherwise tend to disregard that bit. Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. biwa at att.net K6OQK From xde-l2g3 at myamail.com Mon Nov 2 08:50:35 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Mon, 02 Nov 2009 03:50:35 -0500 Subject: [time-nuts] WWV Clock References: <20091101232654.GB69624@puck.nether.net> Message-ID: "Majdi S. Abbas" wrote: > On Sun, Nov 01, 2009 at 05:51:24PM -0500, Glenn Little WB4UIV > wrote: >> My WWV clock at home and the master clock at the TV station that >> I am engineer for did not update to EST from EDT. >> Did anyone else see their WWV clock not change time for DST? > WWVB does have a bit that accounts for it, but most of those > clocks just try to update once a day, and if they take a single > bit error in the minute or two they check, they'll miss it. [...] > Majdi, N0RMZ I don't know if WWV receivers work this way, but WWVB clocks start looking at midnight and repeat every hour until 06:00, or until they get a valid signal. Once they update, they no longer look for the time signal until the next midnight. If the signal is strong enough to update at midnight, the clock will miss the time change at 2:00 am. So they will be off by one hour until the next update. In this case, the problem is not due to a weak signal causing a single bit error, it is due to a strong signal and receiving all the bits correctly on the first attempt. In my case, the GCD distance between Toronto and Fort Collins is 1333 miles (2144 km, 1158 nautical miles), and the direction is 269.6 degrees: The NIST WWVB Coverage maps show the signal in Toronto is good at 0000UTC, and the receiver will probably synchronize on the first attempt at midnight (0500UTC): So all my WWVB clocks missed the time change on the first day. For reference, the clocks are HTAWI HAA-1203W 12" White Atomic Analog Wall Clock: > They have been on sale for $14.95 for several years, and I can recommend them highly. Good styling, very economical, and excellent reception. When I first got them, I was amazed to see them synchronize at 5:00pm local time when the signals are very weak in Toronto. The only problem is they make a loud tick every second, which is the same as any digital clock movement. One day I will take them apart and put a small resistor and speedup capacitor in series with the motor to quiet them. Regards, Mike Monett From rk at timing-consultants.com Mon Nov 2 09:35:11 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Mon, 2 Nov 2009 09:35:11 -0000 Subject: [time-nuts] IRIG B(1) sample wav file In-Reply-To: <7.0.1.0.1.20091031222643.0204f298@tapko.de> References: <970313.79768.qm@web27107.mail.ukl.yahoo.com><200910310910140207.12352F2F@192.168.42.129> <7.0.1.0.1.20091031222643.0204f298@tapko.de> Message-ID: It depends on the IRIG card used. With a basic reader card you can sync down to 1 millisecond based on the 1 KHz IRIG-B time code. More elaborate cards have a phase locked 10 MHz oscillator on board, and software to replace the PC's RTC so time comes directly from the card. Sync to a few microseconds and lower is possible. Take a look at Symmetricom (board level products originally from Datum), and Spectracom (boards originally from Odetics via KSI). Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Predrag Dukic Sent: 31 October 2009 21:30 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] IRIG B(1) sample wav file Does anybody know what is the time difference (or error) between two PC-s set this way? (I mean the difference between two PC internal RTCs). Can this method be used to sinc two sound cards, contained in two PCs some distance apart. Predrag Dukic At 17:10 31.10.2009, you wrote: > There's a nice package called NMEATime which will generate > IRIG-B code using your sound card. > > http://www.visualgps.net/NMEATime/default.htm > > Lots of other neat software on that site as well. I bought > VisualGPS and NMEATime many moons ago. > > Happy tweaking. > >*********** REPLY SEPARATOR *********** > >On 31-Oct-09 at 15:50 Robert Atkinson wrote: > > >Hi, > >Anybody got a .wav file of a modulated IRIG-B timecode? I just want > >something to do a quick test on a display. My nomal IRIG generator is > >buried in the garage. A simple app to drive a sound card would also do. I > >know at least one of the Linux NTP implementaions can do this but I'm not > >running Linux and don't really want to do a lot of setting up, just a > >quick go/no-go check. > > > >Robert G8RPI. > > > > > > > >_______________________________________________ > >time-nuts mailing list -- time-nuts at febo.com > >To unsubscribe, go to > >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >and follow the instructions there. > > > >__________ Information from ESET Smart Security, version of virus > >signature database 4560 (20091031) __________ > > > >The message was checked by ESET Smart Security. > > > >http://www.eset.com > > >-=-=-=-=-=-=-=-=-=-=-=- >Bruce Lane, Owner & Head Hardware Heavy, >Blue Feather Technologies -- http://www.bluefeathertech.com >kyrrin (at) bluefeathertech do/t c=o=m >"Quid Malmborg in Plano..." > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET NOD32 Antivirus, version of virus >signature database 4561 (20091031) __________ > >The message was checked by ESET NOD32 Antivirus. > >http://www.eset.com _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From rk at timing-consultants.com Mon Nov 2 09:44:27 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Mon, 2 Nov 2009 09:44:27 -0000 Subject: [time-nuts] IRIG B(1) sample wav file In-Reply-To: <7.0.1.0.1.20091031222643.0204f298@tapko.de> References: <970313.79768.qm@web27107.mail.ukl.yahoo.com><200910310910140207.12352F2F@192.168.42.129> <7.0.1.0.1.20091031222643.0204f298@tapko.de> Message-ID: <07850C6ECB6640CAA9625A3DA2A6D662@robinHP> See also http://www.meinberg.de/english/products/index.htm#single_sync Very competitively priced products from nice friendly company. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Predrag Dukic Sent: 31 October 2009 21:30 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] IRIG B(1) sample wav file Does anybody know what is the time difference (or error) between two PC-s set this way? (I mean the difference between two PC internal RTCs). Can this method be used to sinc two sound cards, contained in two PCs some distance apart. Predrag Dukic At 17:10 31.10.2009, you wrote: > There's a nice package called NMEATime which will generate > IRIG-B code using your sound card. > > http://www.visualgps.net/NMEATime/default.htm > > Lots of other neat software on that site as well. I bought > VisualGPS and NMEATime many moons ago. > > Happy tweaking. > >*********** REPLY SEPARATOR *********** > >On 31-Oct-09 at 15:50 Robert Atkinson wrote: > > >Hi, > >Anybody got a .wav file of a modulated IRIG-B timecode? I just want > >something to do a quick test on a display. My nomal IRIG generator is > >buried in the garage. A simple app to drive a sound card would also do. I > >know at least one of the Linux NTP implementaions can do this but I'm not > >running Linux and don't really want to do a lot of setting up, just a > >quick go/no-go check. > > > >Robert G8RPI. > > > > > > > >_______________________________________________ > >time-nuts mailing list -- time-nuts at febo.com > >To unsubscribe, go to > >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >and follow the instructions there. > > > >__________ Information from ESET Smart Security, version of virus > >signature database 4560 (20091031) __________ > > > >The message was checked by ESET Smart Security. > > > >http://www.eset.com > > >-=-=-=-=-=-=-=-=-=-=-=- >Bruce Lane, Owner & Head Hardware Heavy, >Blue Feather Technologies -- http://www.bluefeathertech.com >kyrrin (at) bluefeathertech do/t c=o=m >"Quid Malmborg in Plano..." > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET NOD32 Antivirus, version of virus >signature database 4561 (20091031) __________ > >The message was checked by ESET NOD32 Antivirus. > >http://www.eset.com _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From stijena at tapko.de Mon Nov 2 10:00:57 2009 From: stijena at tapko.de (Predrag Dukic) Date: Mon, 02 Nov 2009 11:00:57 +0100 Subject: [time-nuts] IRIG B(1) sample wav file In-Reply-To: References: <970313.79768.qm@web27107.mail.ukl.yahoo.com> <200910310910140207.12352F2F@192.168.42.129> <7.0.1.0.1.20091031222643.0204f298@tapko.de> Message-ID: <7.0.1.0.1.20091102105455.01fe8e58@tapko.de> Well, for my application, probably 1 ms is sufficient. Is it possible with NMEATime alone, without any additional hardware? That is what was my question about in the first place. Thanks for all other suggestions, they will certainly be used in the future, but NMEATime looks like my solution for 1ms. From the NMEATime page it seems it uses bit-banging for PPS signal, possibly triggering serial interrupt directly. If that is true, it could even be better than 1 ms. (?) P. Dukic At 10:35 2.11.2009, you wrote: >It depends on the IRIG card used. With a basic reader card you can sync down >to 1 millisecond based on the 1 KHz IRIG-B time code. More elaborate cards >have a phase locked 10 MHz oscillator on board, and software to replace the >PC's RTC so time comes directly from the card. Sync to a few microseconds >and lower is possible. Take a look at Symmetricom (board level products >originally from Datum), and Spectracom (boards originally from Odetics via >KSI). > >Rob Kimberley > >-----Original Message----- >From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On >Behalf Of Predrag Dukic >Sent: 31 October 2009 21:30 >To: Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] IRIG B(1) sample wav file > > > > >Does anybody know what is the time difference (or error) between two >PC-s set this way? > >(I mean the difference between two PC internal RTCs). > >Can this method be used to sinc two sound cards, contained in two PCs >some distance apart. > >Predrag Dukic > > > > > > >At 17:10 31.10.2009, you wrote: > > There's a nice package called NMEATime which will generate > > IRIG-B code using your sound card. > > > > http://www.visualgps.net/NMEATime/default.htm > > > > Lots of other neat software on that site as well. I bought > > VisualGPS and NMEATime many moons ago. > > > > Happy tweaking. > > > >*********** REPLY SEPARATOR *********** > > > >On 31-Oct-09 at 15:50 Robert Atkinson wrote: > > > > >Hi, > > >Anybody got a .wav file of a modulated IRIG-B timecode? I just want > > >something to do a quick test on a display. My nomal IRIG generator is > > >buried in the garage. A simple app to drive a sound card would also do. I > > >know at least one of the Linux NTP implementaions can do this but I'm not > > >running Linux and don't really want to do a lot of setting up, just a > > >quick go/no-go check. > > > > > >Robert G8RPI. > > > > > > > > > > > >_______________________________________________ > > >time-nuts mailing list -- time-nuts at febo.com > > >To unsubscribe, go to > > >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > >and follow the instructions there. > > > > > >__________ Information from ESET Smart Security, version of virus > > >signature database 4560 (20091031) __________ > > > > > >The message was checked by ESET Smart Security. > > > > > >http://www.eset.com > > > > > >-=-=-=-=-=-=-=-=-=-=-=- > >Bruce Lane, Owner & Head Hardware Heavy, > >Blue Feather Technologies -- http://www.bluefeathertech.com > >kyrrin (at) bluefeathertech do/t c=o=m > >"Quid Malmborg in Plano..." > > > > > >_______________________________________________ > >time-nuts mailing list -- time-nuts at febo.com > >To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >and follow the instructions there. > > > >__________ Information from ESET NOD32 Antivirus, version of virus > >signature database 4561 (20091031) __________ > > > >The message was checked by ESET NOD32 Antivirus. > > > >http://www.eset.com > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET NOD32 Antivirus, version of virus >signature database 4563 (20091101) __________ > >The message was checked by ESET NOD32 Antivirus. > >http://www.eset.com From xde-l2g3 at myamail.com Mon Nov 2 10:10:55 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Mon, 02 Nov 2009 05:10:55 -0500 Subject: [time-nuts] WWV Clock References: Message-ID: Replying to my own post, there are two bits that indicate daylight saving time changes. Here's a paragraph from page 27, Lombardi, "NIST Time and Frequency Services", NIST Special Publication 432, 2002 Edition: "Daylight saving time (DST) and standard time (ST) information is transmitted at seconds 57 and 58. When ST is in effect, bits 57 and 58 are set to 0. When DST is in effect, bits 57 and 58 are set to 1." "On the day of a change from ST to DST bit 57 changes from 0 to 1 at 0000 UTC, and bit 58 changes from 0 to 1 exactly 24 hours later. On the day of a change from DST back to ST bit 57 changes from 1 to 0 at 0000 UTC, and bit 58 changes from 1 to 0 exactly 24 hours later." So it seems the HTAWI receives the bits correctly, but it does not act on them until both are the same. Some relevant articles are available: NIST Special Publication 432, 2002 Edition NIST Special Publication 250-67 WWVB RCC Recommended Practices 2009 Regards, Mike Monett From robinkimberley at btinternet.com Mon Nov 2 10:52:58 2009 From: robinkimberley at btinternet.com (Rob Kimberley) Date: Mon, 2 Nov 2009 10:52:58 -0000 Subject: [time-nuts] FE-5680 Frequency Settings Message-ID: Anyone got info on changing frequency of DDS on FE-5680? Would like to change a 15 MHz unit to provide 2.048 MHz. Had a quick scan of previous posts but can't see anything. Thanks. Rob Kimberley From ernieperes at aol.com Mon Nov 2 13:34:05 2009 From: ernieperes at aol.com (ernieperes at aol.com) Date: Mon, 02 Nov 2009 08:34:05 -0500 Subject: [time-nuts] Z38XX In-Reply-To: <362032A6E84D42AF93330091F4AACE8F@athlon> Message-ID: <8CC29D84867D3E7-27B8-94C@webmail-d036.sysops.aol.com> Hi Ulrich, Thanks a lot for the reply.... still my QQQQQ is ... when you open the "parameters " window it is asking what is line nbr of tracked/untracked sats....????? and the default is line nbr 11...and sats data line nbr from 13 to sats data line to 18, but I believe if I change the line nbr....I can get the correct nbr of sats tracked and not tracked....but I do not know the orig HP SW structural info..which line contains this data??????. meaning which line contains the tracked sats??????????????? I have the Z3801 GPSDO. Did you get my question?????? Rgds Ernie. -----Original Message----- From: Ulrich Bangert To: ernieperes at aol.com Sent: Mon, Nov 2, 2009 11:51 am Subject: AW: Z38XX Ernie, the latest version 2009-07-19 should have no more configuration concerning line numbers! Wo what do you mean by > ie line nbr etc..etc / to read the correct tracked sats nbr??????? there is a configuration necessary concerning the serial port operating parameters. Are you referring to that? I don't know how to set them correct for the Z3801 since I own a Z3805 but you may ask other users of the software in the time nuts group. What you can do in any case: Open the debug window and log what happening into a file for few minutes. Send me the file and I can try to diagnose whats going wrong. Best regards Ulrich -----Urspr?ngliche Nachricht----- Von: ernieperes at aol.com [mailto:ernieperes at aol.com] Gesendet: Montag, 2. November 2009 11:36 An: df6jb at ulrich-bangert.de Betreff: Z38XX Hi Ulrich, I have all the version of this program but presently using the latest update / Z38XX 2009-07-19 / for my HP Z3801 GPSDO but having a little problem.... Namely...... the display says about the birds ...visible 1, tracked 1, but when I view the receives status the same time it displays tracking 4 and not tracking 4...... can you please advise how to set up the " Parameter " page / ie line nbr etc..etc / to read the correct tracked sats nbr??????? and also the " EFC/SAT " display shows only 1 sats....... Many thanks in advance for your help. Best regards, Ernie, HG5ED. From ssybert at kb1fxy.us Mon Nov 2 14:14:26 2009 From: ssybert at kb1fxy.us (Scott A Sybert) Date: Mon, 2 Nov 2009 06:14:26 -0800 Subject: [time-nuts] FS: *REDUCED* Brandywine GPS-4 Units & Antennas - 2 sets available - $350ea References: <15D717421F0B004A82877D8DFEDF912B058ACE@ex14.hostedexchange.local> Message-ID: <15D717421F0B004A82877D8DFEDF912B058B4A@ex14.hostedexchange.local> Hi Guys, I thoguht I'd give it one more shot here before I sent these to eBay. I am adomately against their excessive fees so I just assume pass the fees along as savings to a list member rather than pay it to eBay. I'll reduce the price to $350.00 for a Bradywine GPS-4 PLUS a complete antenna kit... SHIPPED FREE (US). I accept paypal, money orders and personal checks. PayPal please add 3%. Scott KB1FXY ssybert at kb1fxy.us ________________________________ From: Scott A Sybert Sent: Sun 10/18/2009 9:32 PM To: time-nuts at febo.com Subject: FOR SALE: Brandywine GPS-4 Units & Antennas - 2 sets available Hello Everyone, I have two more Brandywine GPS-4 units available with brand new Panasonic antennas and coax kits. Same price as last time... $400 for the GPS and $40 for the antenna kit. As usual, shipping is always free (US only. International shipping will be additional). I prefer personal checks or money orders but will accept paypal for an additional 3%. If anyone is interested, please send me an email off the list. Regards, Scott KB1FXY ssybert at kb1fxy.us From ssybert at kb1fxy.us Mon Nov 2 14:20:22 2009 From: ssybert at kb1fxy.us (Scott A Sybert) Date: Mon, 2 Nov 2009 06:20:22 -0800 Subject: [time-nuts] *REDUCED* Brandywine GPS-4 Units & Antennas - 2 sets available - $350ea References: <15D717421F0B004A82877D8DFEDF912B058ACE@ex14.hostedexchange.local> <15D717421F0B004A82877D8DFEDF912B058B4A@ex14.hostedexchange.local> Message-ID: <15D717421F0B004A82877D8DFEDF912B058B4B@ex14.hostedexchange.local> I apologize for the horrible spelling... How embarassing. Allow me to use spell checker this time :) ________________________________ From: Scott A Sybert Sent: Mon 11/2/2009 9:14 AM To: time-nuts at febo.com Subject: FS: *REDUCED* Brandywine GPS-4 Units & Antennas - 2 sets available - $350ea Hi Guys, I thought I'd give it one more shot here before I sent these to eBay. I am adamantly against their excessive fees so I just assume pass the fees along as savings to a list member rather than pay it to eBay. I'll reduce the price to $350.00 for a Bradywine GPS-4 PLUS a complete antenna kit... SHIPPED FREE (US). I accept paypal, money orders and personal checks. PayPal please add 3%. Scott KB1FXY ssybert at kb1fxy.us ________________________________ From: Scott A Sybert Sent: Sun 10/18/2009 9:32 PM To: time-nuts at febo.com Subject: FOR SALE: Brandywine GPS-4 Units & Antennas - 2 sets available Hello Everyone, I have two more Brandywine GPS-4 units available with brand new Panasonic antennas and coax kits. Same price as last time... $400 for the GPS and $40 for the antenna kit. As usual, shipping is always free (US only. International shipping will be additional). I prefer personal checks or money orders but will accept paypal for an additional 3%. If anyone is interested, please send me an email off the list. Regards, Scott KB1FXY ssybert at kb1fxy.us From pvince at theiet.org Mon Nov 2 15:09:47 2009 From: pvince at theiet.org (Peter Vince) Date: Mon, 2 Nov 2009 15:09:47 +0000 Subject: [time-nuts] FE-5680 Frequency Settings In-Reply-To: References: Message-ID: Hi Rob, Some information in Didier's manuals archive at: http://www.ko4bb.com/cgi-bin/manuals.pl?dir=05%29_GPS_Timing/FEI TTFN, Peter Vince 2009/11/2 Rob Kimberley : > > Anyone got info on changing frequency of DDS on FE-5680? Would like to > change a 15 MHz unit to provide 2.048 MHz. > > Had a quick scan of previous posts but can't see anything. > > Thanks. > > Rob Kimberley From rk at timing-consultants.com Mon Nov 2 15:33:21 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Mon, 2 Nov 2009 15:33:21 -0000 Subject: [time-nuts] FE-5680 Frequency Settings In-Reply-To: References: Message-ID: <1F6A295BDDBC4F9D94FB2CF9380EC154@robinHP> Thanks Peter! Are you going to the NPL T&F Club meeting in December? I'm hoping to get down this time after missing the last two (or was it three?!) Rob -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Peter Vince Sent: 02 November 2009 15:10 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680 Frequency Settings Hi Rob, Some information in Didier's manuals archive at: http://www.ko4bb.com/cgi-bin/manuals.pl?dir=05%29_GPS_Timing/FEI TTFN, Peter Vince 2009/11/2 Rob Kimberley : > > Anyone got info on changing frequency of DDS on FE-5680? Would like to > change a 15 MHz unit to provide 2.048 MHz. > > Had a quick scan of previous posts but can't see anything. > > Thanks. > > Rob Kimberley _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From brooke at pacific.net Mon Nov 2 15:50:25 2009 From: brooke at pacific.net (Brooke Clarke) Date: Mon, 02 Nov 2009 07:50:25 -0800 Subject: [time-nuts] WWV Clock In-Reply-To: References: Message-ID: <4AEEFFC1.9030807@pacific.net> Hi Mike: Note that the way a clock checks to see of it has received the data correctly is to compare two adjacent frames and check to see that they differ by one minute. If the clock was smart it would start to listen a few minutes prior to midnight and would recognize that there was going to be a DST change at midnight. If the clock started at what it thought was midnight, but it was running a second slow then it would miss the first frame, but the next minute it would get the "new" frame and switch to/from DST. I think your clock is just not receiving a good enough signal. The key may be you need to mount the clock on a wall that's 90 degrees from where it is now. That's the problem I had with an atomic clock, i.e. the loopstick antenna has deep nulls and if you point the null at the transmitter . . . See: http://www.prc68.com/I/Shadow-Clock.shtml#WT5360U I like the projection clock in my bedroom. No glasses, no light needed to tell the time. Have Fun, Brooke Clarke http://www.prc68.com Mike Monett wrote: > Replying to my own post, there are two bits that indicate daylight > saving time changes. Here's a paragraph from page 27, Lombardi, > "NIST Time and Frequency Services", NIST Special Publication 432, > 2002 Edition: > > "Daylight saving time (DST) and standard time (ST) information is > transmitted at seconds 57 and 58. When ST is in effect, bits 57 and > 58 are set to 0. When DST is in effect, bits 57 and 58 are set to > 1." > > "On the day of a change from ST to DST bit 57 changes from 0 to 1 at > 0000 UTC, and bit 58 changes from 0 to 1 exactly 24 hours later. On > the day of a change from DST back to ST bit 57 changes from 1 to 0 > at 0000 UTC, and bit 58 changes from 1 to 0 exactly 24 hours later." > > > > So it seems the HTAWI receives the bits correctly, but it does not > act on them until both are the same. > > Some relevant articles are available: > > NIST Special Publication 432, 2002 Edition > NIST Special Publication 250-67 > WWVB RCC Recommended Practices 2009 > > > > Regards, > > Mike Monett > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From Murray.Greenman at rakon.com Mon Nov 2 18:18:36 2009 From: Murray.Greenman at rakon.com (Murray Greenman) Date: Tue, 3 Nov 2009 07:18:36 +1300 Subject: [time-nuts] FE-5680 frequency change In-Reply-To: References: Message-ID: Rob, It will depend on which version you have. I've not seen a dedicated 15MHz unit, so can't be sure which synthesis scheme it uses. If it has a dedicated fixed synthesizer, you may be out of luck. However, if (like the 1pps models) it has a DDS synthesizer, the frequency change can be done via a serial command. For details see: http://www.mail-archive.com/time-nuts at febo.com/msg13486.html http://www.leapsecond.com/museum/fei5650a/ http://www.qsl.net/zl1bpu/PRECISION/FE-5650A.htm The DDS board can be identified by comparing it with the photo at: http://www.leapsecond.com/museum/fei5650a/freq_divider.jpg Bear in mind that the photo might be the other way around from the angle you get to view it at. If you have the DDS version (it's the same in the FE-5650A and FE-5680A), you're in luck, and can program any frequency from DC to 20MHz or so. You might consider buying another dedicated unit for 2.048MHz. Bob Mokia (NHBBob on Ebay) has the 1pps versions for sale, and these are easily converted to remote frequency programming, as described in the links above. Regards, Murray Greenman From bill at iaxs.net Mon Nov 2 18:57:22 2009 From: bill at iaxs.net (Bill Hawkins) Date: Mon, 2 Nov 2009 12:57:22 -0600 Subject: [time-nuts] WWV Clock In-Reply-To: <4AEEFFC1.9030807@pacific.net> References: <4AEEFFC1.9030807@pacific.net> Message-ID: <1CDBC743BC35407699E875B31B04142F@cyrus> Um, the time change takes place at 2 AM in the USA, springing ahead to 3 AM or falling back to 1 AM. This avoids repeating the date in the fall. Surely, other cultures don't do it differently, do they? ;-) Bill Hawkins It's widely true that the time of minimum human activity is 4:30 AM. Why not do it then? -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Brooke Clarke Sent: Monday, November 02, 2009 9:50 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] WWV Clock Hi Mike: Note that the way a clock checks to see of it has received the data correctly is to compare two adjacent frames and check to see that they differ by one minute. If the clock was smart it would start to listen a few minutes prior to midnight and would recognize that there was going to be a DST change at midnight. If the clock started at what it thought was midnight, but it was running a second slow then it would miss the first frame, but the next minute it would get the "new" frame and switch to/from DST. I think your clock is just not receiving a good enough signal. The key may be you need to mount the clock on a wall that's 90 degrees from where it is now. That's the problem I had with an atomic clock, i.e. the loopstick antenna has deep nulls and if you point the null at the transmitter . . . See: http://www.prc68.com/I/Shadow-Clock.shtml#WT5360U I like the projection clock in my bedroom. No glasses, no light needed to tell the time. Have Fun, Brooke Clarke http://www.prc68.com From brooke at pacific.net Mon Nov 2 19:08:55 2009 From: brooke at pacific.net (Brooke Clarke) Date: Mon, 02 Nov 2009 11:08:55 -0800 Subject: [time-nuts] WWV Clock In-Reply-To: <1CDBC743BC35407699E875B31B04142F@cyrus> References: <4AEEFFC1.9030807@pacific.net> <1CDBC743BC35407699E875B31B04142F@cyrus> Message-ID: <4AEF2E47.9080903@pacific.net> Hi Bill: My bad. 2 am is when the bars close. Any change prior to then would be a problem. After 2 pm there's not many who care. Have Fun, Brooke Clarke http://www.prc68.com Bill Hawkins wrote: > Um, the time change takes place at 2 AM in the USA, springing ahead to > 3 AM or falling back to 1 AM. This avoids repeating the date in the fall. > > Surely, other cultures don't do it differently, do they? ;-) > > Bill Hawkins > > It's widely true that the time of minimum human activity is 4:30 AM. > Why not do it then? > > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Brooke Clarke > Sent: Monday, November 02, 2009 9:50 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] WWV Clock > > Hi Mike: > > Note that the way a clock checks to see of it has received the data > correctly > is to compare two adjacent frames and check to see that they differ by one > minute. > > If the clock was smart it would start to listen a few minutes prior to > midnight > and would recognize that there was going to be a DST change at midnight. > > If the clock started at what it thought was midnight, but it was running a > second slow then it would miss the first frame, but the next minute it would > > get the "new" frame and switch to/from DST. > > I think your clock is just not receiving a good enough signal. The key may > be > you need to mount the clock on a wall that's 90 degrees from where it is > now. > That's the problem I had with an atomic clock, i.e. the loopstick antenna > has > deep nulls and if you point the null at the transmitter . . . See: > http://www.prc68.com/I/Shadow-Clock.shtml#WT5360U > > I like the projection clock in my bedroom. No glasses, no light needed to > tell > the time. > > Have Fun, > > Brooke Clarke > http://www.prc68.com > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From xde-l2g3 at myamail.com Mon Nov 2 21:02:20 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Mon, 02 Nov 2009 16:02:20 -0500 Subject: [time-nuts] WWV Clock References: <4AEEFFC1.9030807@pacific.net> Message-ID: Brooke Clarke wrote: > Hi Mike: > Note that the way a clock checks to see of it has received the > data correctly is to compare two adjacent frames and check to see > that they differ by one minute. > If the clock was smart it would start to listen a few minutes > prior to midnight and would recognize that there was going to be a > DST change at midnight. > If the clock started at what it thought was midnight, but it was > running a second slow then it would miss the first frame, but the > next minute it would get the "new" frame and switch to/from DST. > I think your clock is just not receiving a good enough signal. The > key may be you need to mount the clock on a wall that's 90 degrees > from where it is now. > That's the problem I had with an atomic clock, ie the loopstick > antenna has deep nulls and if you point the null at the > transmitter . . . See: > http://www.prc68.com/I/Shadow-Clock.shtml#WT5360U > I like the projection clock in my bedroom. No glasses, no light > needed to tell the time. >Have Fun, >Brooke Clarke >http://www.prc68.com Hi Brooke, Thanks for the note. As the paragraph in tech pub 432 says, "On the day of a change from ST to DST bit 57 changes from 0 to 1 at 0000 UTC, and bit 58 changes from 0 to 1 exactly 24 hours later. On the day of a change from DST back to ST bit 57 changes from 1 to 0 at 0000 UTC, and bit 58 changes from 1 to 0 exactly 24 hours later." As you can see, the first bit (57) changes at 0000 GMT. However, Eastern Standard Time starts 5 hours later, so all the radios in the US and Canada already know the bit is set when they start updating at their local midnight. The problem is this particular brand seems to ignore bit 57, and only pays attention to bit 58. The clocks are mounted in two buildings several blocks apart. I found the optimum location for each by forcing a manual synchronization and picked the spot that gave the fastest sync. The bearing to Fort Collins is around 270 degrees. Both walls run about 225 degrees, or about 45 degrees from the desired bearing. Here is a picture of a loop with the desired orientation: So the actual orientation is not ideal, but the loop has a much flatter radiation pattern with a sharper and narrower null than shown above, and the signal loss is not as bad as you might expect. As I mentioned earlier, this brand has excellent sensitivity, and will usually synchronize manually starting around 5:00pm. The proof is the clocks usually synchronize on the first attempt at midnight, so improving the signal strength would not change the outcome. Since the clocks are about 45 degrees from full broadside, changing the orientation by 90 degrees would not change the signal strength. They would still be 45 degrees off the desired bearing. But they run fine and keep perfect time. Thanks for the note on your projection clock. I have been looking for a silent WWVB clock with a lighted face for a long time, but had no luck. The WT-5360U looks like the perfect solution. I'll get one on order right away. Best Regards, Mike Monett From rk at timing-consultants.com Mon Nov 2 22:22:19 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Mon, 2 Nov 2009 22:22:19 -0000 Subject: [time-nuts] FE-5680 frequency change In-Reply-To: References: Message-ID: Murray, Many thanks! Rob -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Murray Greenman Sent: 02 November 2009 18:19 To: time-nuts at febo.com Subject: [time-nuts] FE-5680 frequency change Rob, It will depend on which version you have. I've not seen a dedicated 15MHz unit, so can't be sure which synthesis scheme it uses. If it has a dedicated fixed synthesizer, you may be out of luck. However, if (like the 1pps models) it has a DDS synthesizer, the frequency change can be done via a serial command. For details see: http://www.mail-archive.com/time-nuts at febo.com/msg13486.html http://www.leapsecond.com/museum/fei5650a/ http://www.qsl.net/zl1bpu/PRECISION/FE-5650A.htm The DDS board can be identified by comparing it with the photo at: http://www.leapsecond.com/museum/fei5650a/freq_divider.jpg Bear in mind that the photo might be the other way around from the angle you get to view it at. If you have the DDS version (it's the same in the FE-5650A and FE-5680A), you're in luck, and can program any frequency from DC to 20MHz or so. You might consider buying another dedicated unit for 2.048MHz. Bob Mokia (NHBBob on Ebay) has the 1pps versions for sale, and these are easily converted to remote frequency programming, as described in the links above. Regards, Murray Greenman _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From W4wj at aol.com Tue Nov 3 07:03:21 2009 From: W4wj at aol.com (W4wj at aol.com) Date: Tue, 3 Nov 2009 02:03:21 EST Subject: [time-nuts] Fwd: [VintageSS] BC221 Frequency Meter Message-ID: Here is something for a time nuts WWII setup... 73, Don, W4WJ ____________________________________ From: bcarling at cfl.rr.com To: usedhamgear at yahoogroups.com, usedradioequipment at yahoogroups.com, VintageSS at yahoogroups.com Sent: 11/2/2009 4:10:22 A.M. Central Standard Time Subj: [VintageSS] BC221 Frequency Meter FOR SALE: BC221 Frequency Meter Here is a standard unmodified BC-221 Frequency Meter and it comes with the book. Beautifully built military spec equipment with a dial drive and tuning capacitor that are ideal for a project like a VFO or a remote VFO or even a homebrew receiver or transceiver. Appearance is excellent inside. There is minor surface rust on the catches on the outside of the case, but it's nothing serious at all. For its age this instrument is in superior condition compared to most of these that I have seen. Available for $49.00 plus shipping. 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Groups _Small Business Group_ (http://us.ard.yahoo.com/SIG=14hqt6t5c/M=493064.12016272.13586184.8674578/D=groups/S=1705063108:NC/Y=YAHOO/EXP=1257163816/L=/B=n _nNGkPDhFA-/J=1257156616179142/K=g_fqMEU7CzScCjlj.irAgw/A=5758220/R=0/SIG=12 4m43uve/*http://finance.groups.yahoo.com/group/BankofAmerica_SmallBusiness/) A community for small business owners Yahoo! Groups _Auto Enthusiast Zone_ (http://us.ard.yahoo.com/SIG=14h2kf97a/M=493064.12717544.13455789.8674578/D=groups/S=1705063108:NC/Y=YAHOO/EXP=1257163816/L=/B=o PnNGkPDhFA-/J=1257156616179142/K=g_fqMEU7CzScCjlj.irAgw/A=5658250/R=0/SIG=11 ptgj47g/*http://advision.webevents.yahoo.com/autoenthusiastzone/) Auto Enthusiast Zone Car groups and more! . __,_._,___ From jfor at quik.com Tue Nov 3 07:26:32 2009 From: jfor at quik.com (J. Forster) Date: Mon, 2 Nov 2009 23:26:32 -0800 (PST) Subject: [time-nuts] Fwd: [VintageSS] BC221 Frequency Meter In-Reply-To: References: Message-ID: <4051.12.6.201.74.1257233192.squirrel@popacctsnew.quik.com> A BC-221 is a remarkable piece of hardware. Among other things it can be used either as a source (oscillator) or measuring instrument (heterodyne frequency meter). -John ========== > Here is something for a time nuts WWII setup... > > > 73, Don, W4WJ > > > > > > ____________________________________ > From: bcarling at cfl.rr.com > To: usedhamgear at yahoogroups.com, usedradioequipment at yahoogroups.com, > VintageSS at yahoogroups.com > Sent: 11/2/2009 4:10:22 A.M. Central Standard Time > Subj: [VintageSS] BC221 Frequency Meter > > > > > > FOR SALE: BC221 Frequency Meter > > Here is a standard unmodified BC-221 Frequency Meter and it comes with > the book. > Beautifully built military spec equipment with a dial drive and tuning > capacitor that are > ideal for a project like a VFO or a remote VFO or even a homebrew > receiver or transceiver. > > Appearance is excellent inside. There is minor surface rust on the > catches > on > the outside of the case, but it's nothing serious at all. For its age > this > instrument > is in superior condition compared to most of these that I have seen. > Available for $49.00 plus shipping. > Pictures and details at: > _http://www.af4k.http://www.htt_ (http://www.af4k.com/radios.htm) > > 73 - Brian Carling, AF4K From iovane at inwind.it Tue Nov 3 22:05:30 2009 From: iovane at inwind.it (iovane at inwind.it) Date: Tue, 3 Nov 2009 23:05:30 +0100 (CET) Subject: [time-nuts] LPRO101 Lamp Exciter Frequency Message-ID: <25191930.94401257285930323.JavaMail.defaultUser@defaultHost> rbarrioss at msn.com wrote: Date: 26/10/2009 7.54 >Yes, everything I've seen points me to think that the oscillator runs at 140Mhz and not 70. ....... > >Please, come back to us when you measure the exciter frequency on your LPRO, thank you. Roberto, I've done the check. Please excuse me for the delay due to the fact that I have my stuff spread across two locations 250 Km apart. Last week-end I fetched a working Rb and brought it here where I have spectrum analyzers. No 70 MHz signal at all, you were right. What I can see is 60 MHz, its 120 MHz harmonic and then the about 145 MHz from the lamp ignition oscillator. Probably PE1FBO was misled by me, and I, on my hand, had accepted the occasional 70 MHz reading (made with an hand held counter !) being biased by the FRS specs. I apologize. 73, Antonio I8IOV From SAIDJACK at aol.com Tue Nov 3 22:24:09 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Tue, 3 Nov 2009 17:24:09 EST Subject: [time-nuts] HP/Symmetricom 58535A and 58536A Message-ID: Hi Bjoern, Yes. On our FireFly series GPSDO I get up to 45dB signal to noise ratio with a passive 1-to-4 splitter following the Agilent active splitter. I think there is something going on with the Thunderbolts such as the antenna sense circuit not working properly etc, please also see my other email following this one. bye, Said In a message dated 11/1/2009 04:04:11 Pacific Standard Time, bg at lysator.liu.se writes: Hi Said, > I think the added noise of the Amp may play funny with the Thunderbolt's > receiver, and there may not be anything wrong with your splitter. > > M12M's and uBlox receiver's don't have a problem at all, even if two units > are cascaded. They do start to have issues with three splitters in series. Did you check that you have enough signal power for the Tbolt, when cascading (passive) splitters? -- Bj?rn From SAIDJACK at aol.com Tue Nov 3 22:37:50 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Tue, 3 Nov 2009 17:37:50 EST Subject: [time-nuts] HP/Symmetricom 58535A and 58536A Message-ID: Hello Magnus, yes, interestingly enough the units I have seem to have the option to power them through port-1 removed by brute-force: the inductor on all my units has been ripped off the PCB by force! This holds for the 1-2, 1-4, and 1-8 Agilent/Symmetricom splitters I have, all of them have this rather rude modification made (and they are all from different sources, and vintages). Thus port-1 has no DC load at all, while all the other ports have a DC load to ground for the GPSDO. Maybe this is the problem, I need to see if the Thunderbolt works with or without a DC load.. I am glad I am not the only one having this issue with the Thunderbolt though. One more tidbit on the side: it is not a good idea to mix-and-match GPSDO's that have different antenna voltages (5V and 3.3V for example) on a passive, DC-coupled splitter. This will create a problem. And can also lead to some really interesting results: I have a USB eval board from a Taiwanese company, and noticed that it generated a 1PPS without the USB being plugged-in. Very strange. Turns out the board is getting power and running perfectly well from another GPSDO connected to the same passive antenna splitter, and being fed power from it's own antenna input!! bye, Said In a message dated 11/1/2009 03:19:14 Pacific Standard Time, magnus at rubidium.dyndns.org writes: > The amp is followed by a resistive splitter, and possibly a resistive > attenuator (on the 2-port version). Then a cavity filter, then the N-Connector, > very simple, not much that can go wrong. They do have DC load on the non-DC-thru ports. Check the open/short status on the thunderbolt. It's very easy to see with the Thunderbolt monitor program. Cheers, Magnus From eb4apl at cembreros.jazztel.es Tue Nov 3 23:26:36 2009 From: eb4apl at cembreros.jazztel.es (EB4APL) Date: Wed, 04 Nov 2009 00:26:36 +0100 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: References: Message-ID: <4AF0BC2C.5020806@cembreros.jazztel.es> SAIDJACK at aol.com wrote:: > Hello Magnus, > > yes, interestingly enough the units I have seem to have the option to power > them through port-1 removed by brute-force: the inductor on all my units > has been ripped off the PCB by force! > > This holds for the 1-2, 1-4, and 1-8 Agilent/Symmetricom splitters I have, > all of them have this rather rude modification made (and they are all from > different sources, and vintages). > > Thus port-1 has no DC load at all, while all the other ports have a DC load > to ground for the GPSDO. > > Maybe this is the problem, I need to see if the Thunderbolt works with or > without a DC load.. > > I am glad I am not the only one having this issue with the Thunderbolt > though. > > One more tidbit on the side: it is not a good idea to mix-and-match GPSDO's > that have different antenna voltages (5V and 3.3V for example) on a > passive, DC-coupled splitter. This will create a problem. And can also lead to > some really interesting results: > > I have a USB eval board from a Taiwanese company, and noticed that it > generated a 1PPS without the USB being plugged-in. Very strange. > > Turns out the board is getting power and running perfectly well from > another GPSDO connected to the same passive antenna splitter, and being fed > power from it's own antenna input!! > > bye, > Said > > Hi, It reminds me when I was breadboarding a TVB divider for my Rb clock project. Once I removed the power to the PIC, but the 10 pps led continued blinking at a very low intensity. After minutes of stupefaction and a search for a charged capacitor or other power source, I realized that the beast continued working powered by the 10 Mhz signal !!! Regards, Ignacio Cembreros From magnus at rubidium.dyndns.org Wed Nov 4 00:00:48 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Wed, 04 Nov 2009 01:00:48 +0100 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: References: Message-ID: <4AF0C430.2090700@rubidium.dyndns.org> Hi Said, SAIDJACK at aol.com wrote: > Hello Magnus, > > yes, interestingly enough the units I have seem to have the option to power > them through port-1 removed by brute-force: the inductor on all my units > has been ripped off the PCB by force! > > This holds for the 1-2, 1-4, and 1-8 Agilent/Symmetricom splitters I have, > all of them have this rather rude modification made (and they are all from > different sources, and vintages). Then the Thunderbolt (and several other GPS receivers) will have a problem. They will detect an "open" antenna and fail, regardless of the fact that it may be tracking sats. > Thus port-1 has no DC load at all, while all the other ports have a DC load > to ground for the GPSDO. > > Maybe this is the problem, I need to see if the Thunderbolt works with or > without a DC load.. DC-feed it separately and just move port. Another approach is to put a DC-load-resistor of say 470 ohm in a BNC T-connector, preferably with a series-inductor. That will add about 10 mA of DC load. Kicked a commersial GPS clock alive that badly needed. > I am glad I am not the only one having this issue with the Thunderbolt > though. I think one should view it as learning how they work. The function is actually a safe-guard, but it requires a bit more controlled environment than we sometimes allow ourselves to provide. When running under the propper condition, it will protect the time of the holdover clock from various mishaps where we can expect the sats to be gone or in very high noise condition anyway. > One more tidbit on the side: it is not a good idea to mix-and-match GPSDO's > that have different antenna voltages (5V and 3.3V for example) on a > passive, DC-coupled splitter. This will create a problem. And can also lead to > some really interesting results: > > I have a USB eval board from a Taiwanese company, and noticed that it > generated a 1PPS without the USB being plugged-in. Very strange. > > Turns out the board is getting power and running perfectly well from > another GPSDO connected to the same passive antenna splitter, and being fed > power from it's own antenna input!! Now, that is antenna power! :) Heard on the radio about a professor discussing the possibility to make use of the charge of thunderclouds to charge batteries. He and his team had developed devices that actually did this and got it to opperate. In more tropical environments both heavy thunderclouds and lack of electricity for mobile phones and radios is frequent. Also, it was fairly cheap, maybe 30 dollars or so. Cheers, Magnus From magnus at rubidium.dyndns.org Wed Nov 4 00:09:26 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Wed, 04 Nov 2009 01:09:26 +0100 Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: <4AF0BC2C.5020806@cembreros.jazztel.es> References: <4AF0BC2C.5020806@cembreros.jazztel.es> Message-ID: <4AF0C636.2070400@rubidium.dyndns.org> Hi Ignacio! > It reminds me when I was breadboarding a TVB divider for my Rb clock > project. Once I removed the power to the PIC, but the 10 pps led > continued blinking at a very low intensity. After minutes of > stupefaction and a search for a charged capacitor or other power source, > I realized that the beast continued working powered by the 10 Mhz signal > !!! This is a classic CMOS "feature" as the input protection diodes will provide rectifiers to the supply - oriented in the propper directions. The interesting thing is that devices can behave as almost properly functioning, except for rare occasions of not working, which is when none of the inputs provide the Vcc or GND reference needed. Also, we had this problem with our early hot-swap boards. I had to teach our hardware guides about protection circuits that hooked the inputs to the powerplane and all the caps there, producing a high inrush current unless the drivers where properly isolated. Once the protection was designed in we saw no more of those errors. Have not heard about that kind of problem in the last 10 years now. Power-sequencing in the connectors is there for a reason in some hot-swap systems. So, all connections to a circuit is potential power-supplies. Sometimes it has amusing effects and sometimes it has terrible effects. Cheers, Magnus From david.bengtson at gmail.com Wed Nov 4 02:53:47 2009 From: david.bengtson at gmail.com (David Bengtson) Date: Tue, 3 Nov 2009 21:53:47 -0500 Subject: [time-nuts] Lady Heather Serial receive Error 0x2 Message-ID: Hi All: I'm running what I believe to be the latest version of Lady Heather on a Windows XP laptop. I'm using a USB-Serial interface, and I'm getting this error after about 15 to 20 minutes of data taking. I haven't seen any recent discussion on this problem, I'm curious to know if anyone else has seen this, and if they've figured it out. Once the error message shows up, I quit out and restart the app, and it works fine. I'm starting it with a shortcut "C:\Program Files\Heather\heather.exe" /7 to point it at the com7 serial porty. Thanks Dave From rbarrioss at msn.com Wed Nov 4 16:04:47 2009 From: rbarrioss at msn.com (Roberto Barrios) Date: Wed, 4 Nov 2009 16:04:47 +0000 Subject: [time-nuts] LPRO101 Lamp Exciter Frequency In-Reply-To: References: Message-ID: > Date: Tue, 3 Nov 2009 23:05:30 +0100 (CET) > From: "iovane at inwind.it" > Subject: Re: [time-nuts] LPRO101 Lamp Exciter Frequency > To: > Message-ID: > <25191930.94401257285930323.JavaMail.defaultUser at defaultHost> > Content-Type: text/plain;charset="UTF-8" > > rbarrioss at msn.com wrote: > Date: 26/10/2009 7.54 > > >Yes, everything I've seen > points me to think that the oscillator runs at 140Mhz and not 70. ....... > > > > >Please, come back to us when you measure the exciter frequency on your LPRO, > thank you. > > Roberto, > > I've done the check. Please excuse me for the delay due > to the fact that I have > my stuff spread across two locations 250 Km apart. > Last week-end I fetched a working > Rb and brought it here where I have spectrum > analyzers. > > No 70 MHz signal at all, you were right. What I can see is 60 MHz, > its 120 MHz > harmonic and then the about 145 MHz from the lamp ignition > oscillator. > > Probably PE1FBO was misled by me, and I, on my hand, had accepted > the occasional > 70 MHz reading (made with an hand held counter !) being biased > by the FRS specs. > > I apologize. > > 73, > Antonio I8IOV Hi Antonio, Thank you for taking the time to confirm this. I purchased a second (working) LPRO and it also confirmed that exciter frequency is actually around 150Mhz, as you just saw. Clapp oscillator equations showed that frequency should be much higher that 70Mhz but you never know...It's nice we've been able to clarify this point... it took quite a bit of effort (and risk) to modify the circuit to resonate exactly at 70Mhz, just to find that the lamp would not ignite :-) I've made a few other interesting discoveries that would make for a nice LPRO Repair Guide revision. I'll share the details when I've got everything properly tied. Thank you, Roberto EB4EQA _________________________________________________________________ From cadbloke at hotmail.com Wed Nov 4 17:05:43 2009 From: cadbloke at hotmail.com (gonzo moto) Date: Wed, 4 Nov 2009 17:05:43 +0000 Subject: [time-nuts] Solartron 7150+ filters In-Reply-To: References: Message-ID: Hi Dave, I've rebuilt the second filter and installed it back in the 7150plus (where it is working fine). I kept a photo record which I've combined into a 2.5Mb PDF. I can email it to you or, if someone wants to host it, I'm happy to have it available to all. Cheers, ian > Date: Fri, 30 Oct 2009 00:43:17 +0000 > From: gonzo moto > Subject: Re: [time-nuts] Solartron 7150+ filters > To: time-nuts > Message-ID: > Content-Type: text/plain; charset="iso-8859-1" > > > Hi Dave, > the first filter is complete, but for some potting compound, so it's not very photogenic (I'll take one anyway). > I'll take a full set on the filter that actually failed. > > Cheers, > ian > > > > Date: Thu, 29 Oct 2009 10:47:46 -0000 > > From: "David C. Partridge" > > Subject: [time-nuts] Solartron 7150+ filters > > To: "'Discussion of precise time and frequency measurement'" > > > > Message-ID: <54B8BB1F521540FD9967C72A7EFC5C54 at APOLLO> > > Content-Type: text/plain; charset="us-ascii" > > > > Ian, > > > > If you have time/inclination, I'd be interested to see pics of your > > dissassembly/reassembly process. > > > > Dave > > -----Original Message----- > > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > > Behalf Of gonzo moto > > Sent: 28 October 2009 18:11 > > To: time-nuts > > Subject: Re: [time-nuts] time-nuts Digest, Vol 63, Issue 101 > > I hear you David! > > > > I thought I'd start on the working filter and the repair the smoked unit > > when I know what I'm doing. > > > > I've burrowed inside the filter and was surprised to find the filter caps > > (WIMA MP3-E) are only rated for 250V. > > The MP3-E is a discontinued line (read: I can't find a datasheet). > > These might be ok for European 220V, but my UPS shows my line voltage to > > average 243V, with regular excursions over 250V. > > These caps may be good, but I'd like to see a bit more margin there (it'll > > be going back together with MP3-X2/275V caps). > > > > Robert, while it's not that I don't value my time, my workmanship is up to > > the task, and I'm reluctant to replace a component (possibly with one no > > better than the failed part) when I can fix it better than it was in the > > first place. > > > > ian _________________________________________________________________ Want to know what your boss is paid? Check out The Great Australian Pay Check now http://clk.atdmt.com/NMN/go/157639755/direct/01/ From pvince at theiet.org Wed Nov 4 18:03:35 2009 From: pvince at theiet.org (Peter Vince) Date: Wed, 4 Nov 2009 18:03:35 +0000 Subject: [time-nuts] Does anyone have an Austron 2055A manual please? Message-ID: Would anyone have a manual for the Austron 2055A Phase Microstepper please? Either a PDF, or a paper manual that they are willing to part with (I don't have scanning facilities). Any costs happily reimbursed. Thank you. Peter Vince (G8ZZR, London, England) From stanley_reynolds at yahoo.com Wed Nov 4 18:19:42 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Wed, 4 Nov 2009 10:19:42 -0800 (PST) Subject: [time-nuts] Solartron 7150+ filters In-Reply-To: References: Message-ID: <944153.76278.qm@web30303.mail.mud.yahoo.com> Hi Dave, I've rebuilt the second filter and installed it back in the 7150plus (where it is working fine). I kept a photo record which I've combined into a 2.5Mb PDF. I can email it to you or, if someone wants to host it, I'm happy to have it available to all. Cheers, ian Link: www.n4iqt.com/solartron/solartron-repair.pdf Stanley From bg at lysator.liu.se Wed Nov 4 20:40:13 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Wed, 4 Nov 2009 21:40:13 +0100 (CET) Subject: [time-nuts] HP/Symmetricom 58535A and 58536A In-Reply-To: References: Message-ID: <57464.87.227.52.225.1257367213.squirrel@webmail.lysator.liu.se> Hi Said, Total gain, noise, VSWR are all factors in getting a good signal from the antenna into the receiver. Here all components matter - antenna, the antenna LNA, connectors, type and length of coax cable, splitters and inline LNAs and the receiver spec. Good passive splitters behave well, but they will attenuate your signal by say 6dB (for a 4 output splitter.). Older receivers (always) have a tighter allowance for which total gain they will accept. Moderns high sensitivity receivers give much less trouble in this area. I did not find the numbers from the Tbolt manual. But look at the vintage Oncore receivers, and you will find that legacy receivers sometimes only give you a sub 20dB gain band of total gain. (table 4.1 in below url) http://www.wa5rrn.com/Oncore%20GPS/ch4.pdf Adding (or) substracting 12dB or even 6dB might put your total antenna (antenna, connector, cable, splitter, etc) system out of spec for your Thunderbolt. A HS receiver might not even notice this. Further 6dB extra or less gain does not imply a linear relationship with signal to noice ratio. -- Bj?rn > Hi Bjoern, > > Yes. On our FireFly series GPSDO I get up to 45dB signal to noise ratio > with a passive 1-to-4 splitter following the Agilent active splitter. > > I think there is something going on with the Thunderbolts such as the > antenna sense circuit not working properly etc, please also see my other > email > following this one. > > bye, > Said > > > In a message dated 11/1/2009 04:04:11 Pacific Standard Time, > bg at lysator.liu.se writes: > > Hi Said, > >> I think the added noise of the Amp may play funny with the >> Thunderbolt's >> receiver, and there may not be anything wrong with your splitter. >> >> M12M's and uBlox receiver's don't have a problem at all, even if two > units >> are cascaded. They do start to have issues with three splitters in > series. > > Did you check that you have enough signal power for the Tbolt, when > cascading (passive) splitters? > > -- > > Bj?rn > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From ve7wrs at hotmail.com Thu Nov 5 19:02:07 2009 From: ve7wrs at hotmail.com (VE7WRS) Date: Thu, 5 Nov 2009 11:02:07 -0800 Subject: [time-nuts] RACAL 1996 MATE/CIIL to standard GPIB Message-ID: All, I recently acquired a RACAL 1996-02M counter. This is the MATE/CIIL version. I am hoping to get it to work with Ulrich's EZGPIB and a Prologix adapter. I understand that the CIIL language is different from standard GPIB. I have seen postings discussing a jumper on the RACAL 1992 to switch between languages. Does anyone know how to make a 1996-02M behave like a standard GPIB instrument? Thanks, Walter From kScally at BYTECAN.com.au Thu Nov 5 22:20:02 2009 From: kScally at BYTECAN.com.au (Kit Scally) Date: Fri, 6 Nov 2009 09:20:02 +1100 Subject: [time-nuts] OT - Tag Heuer watch pix In-Reply-To: References: Message-ID: <281090D5003763419A5AC496FF087B2A814C24@msg01nsw.BYTECAN.com.au> Disclaimer - viewing these images may damage you (hip) pocket. *** Slightly off-topic but I know there's some keen horologists amongst us. Enjoy ! Kit VK2LL From sar10538 at gmail.com Thu Nov 5 22:26:46 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Fri, 6 Nov 2009 11:26:46 +1300 Subject: [time-nuts] OT - Tag Heuer watch pix In-Reply-To: <281090D5003763419A5AC496FF087B2A814C24@msg01nsw.BYTECAN.com.au> References: <281090D5003763419A5AC496FF087B2A814C24@msg01nsw.BYTECAN.com.au> Message-ID: <1231b6a80911051426q5eebd1daq817680448267a584@mail.gmail.com> 2009/11/6 Kit Scally : > Disclaimer - viewing these images may damage you (hip) pocket. > *** > Slightly off-topic but I know there's some keen horologists amongst us. > > Enjoy ! > nvents-watch-technology/20091021-h8pw.html> Well, in horology terms it still has pinions and wheels so the description is incorrect. 73, Steve > Kit > VK2LL > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. From alfredorosati at alice.it Fri Nov 6 18:57:13 2009 From: alfredorosati at alice.it (Dott. Alfredo Rosati) Date: Fri, 06 Nov 2009 19:57:13 +0100 Subject: [time-nuts] upgrading agilent 53132 counter In-Reply-To: References: Message-ID: <4AF47189.2020709@alice.it> hello DAVID , may I have a copy of the firmware for my 53132a with old fimware ? regards alfredo From alfredorosati at alice.it Fri Nov 6 20:21:50 2009 From: alfredorosati at alice.it (Dott. Alfredo Rosati) Date: Fri, 06 Nov 2009 21:21:50 +0100 Subject: [time-nuts] fimware 53132A Message-ID: <4AF4855E.8080805@alice.it> i have hp53132A with old firmware . I am locking for a new firmware , someone have a copy ? regards Alfredo From hbonhorst at freenet.de Fri Nov 6 20:48:49 2009 From: hbonhorst at freenet.de (v. Bonhorst) Date: Fri, 6 Nov 2009 21:48:49 +0100 Subject: [time-nuts] Rohde & Schwarz XKE2 Standard frequency receiver In-Reply-To: References: Message-ID: <1789CA94E13341158003B945163DA36D@Shuttle> All, I try to repair a XKE2 and there are two missing diagrams in my paper manual. Exactly these are needed for repair. Diagram for filter board and diagram for antenna . Might be someone can scan these diagrams and help me. Thank you in advance. Best regards, Hubert DB7ME From alan.melia at btinternet.com Fri Nov 6 21:14:23 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Fri, 6 Nov 2009 21:14:23 -0000 Subject: [time-nuts] Rohde & Schwarz XKE2 Standard frequency receiver References: <1789CA94E13341158003B945163DA36D@Shuttle> Message-ID: <001b01ca5f26$205de1e0$0900a8c0@lark> Hi Hubert I have an XKD which I am guessing is the same as yours but mine is tuned for BBC Droitwich on 200kHz (now moved in the early 1990s to 198kHz). I have been unable to find a manual or circuit anywhere. The radio side seems fairly straightforward with 4 tuned amplifier stages, but I have not worked out the phase detector circuit. The divider in the box is just a set of 7490s decade stages in my unit, swiched as required, to provide a signal for the phase detector. If yours is for 77.5kHz DCF77 it will be probably quite different in this area. If you find any information on the circuit I would be interested too even for the XKE. I have used mine with a wire aerial to plot the phase of Droitwich against a local Austron 1250a standard. Best Wishes Alan G3NYK ----- Original Message ----- From: "v. Bonhorst" To: "'Discussion of precise time and frequency measurement'" Sent: Friday, November 06, 2009 8:48 PM Subject: [time-nuts] Rohde & Schwarz XKE2 Standard frequency receiver > All, > I try to repair a XKE2 and there are two missing diagrams in my paper > manual. Exactly these are needed for repair. > Diagram for filter board and diagram for antenna . > Might be someone can scan these diagrams and help me. > Thank you in advance. > Best regards, > Hubert > DB7ME > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From p.arbona at securimar.com Sat Nov 7 09:31:14 2009 From: p.arbona at securimar.com (p.arbona at securimar.com) Date: Sat, 7 Nov 2009 10:31:14 +0100 Subject: [time-nuts] XKE Message-ID: <46B602966CD94AA6ABA69C6A12D49150@pascual01> Hello Hubert, I have the manual for XKE model (not the II) in german . If do you thing is similar, let me know an I will scan the pages that do you need. 73 Pascual Arbona EA5JF From geoff at palaemon.demon.co.uk Sat Nov 7 12:34:17 2009 From: geoff at palaemon.demon.co.uk (Geoff Blake) Date: Sat, 7 Nov 2009 12:34:17 +0000 (GMT) Subject: [time-nuts] time-nuts Digest, Vol 64, Issue 11, XKE2 In-Reply-To: References: Message-ID: > 3. Rohde & Schwarz XKE2 Standard frequency receiver (v. Bonhorst) > > All, > I try to repair a XKE2 and there are two missing diagrams in my paper > manual. Exactly these are needed for repair. > Diagram for filter board and diagram for antenna . > Might be someone can scan these diagrams and help me. > Thank you in advance. > Best regards, > Hubert > DB7ME If you have no further luck, I had a complete system which included the XKE2 and manual. This I sold to a guy in Wales at the beginning of the year. Included in the deal were the manuals as supplied by R&S. In the "package" was the manual for the XKE2 although I believe it was in German. If you let me know, I will look back for the new owners email address and ask him if he can help. Incidentally, it was a 60kHz version. Geoff -- Geoff Blake G8GNZ located near Chelmsford, Essex, U.K. Please reply to: geoff(at)palaemon(dot)demon(dot)co(dot)uk Using Linux on Intel & Linux or NetBSD on Sun Sparc platforms Please avoid sending me Word or PowerPoint attachments. See ----------------------------------------------------------------- This E-mail and any attachment(s) are strictly confidential and is intended solely for the addressee(s). If you are not the intended recipient please notify and the sender by return and permanently delete the message. You may not disclose, forward or copy this E-mail or any of its attachments to any third party without the prior consent of the sender. ---------------------------------------------------------------- From rfnuts at arcor.de Sat Nov 7 12:55:22 2009 From: rfnuts at arcor.de (Adrian) Date: Sat, 07 Nov 2009 13:55:22 +0100 Subject: [time-nuts] OT - Tek 7L18 ROM Message-ID: <4AF56E3A.3080206@arcor.de> Hello all, I have an old 7L18 spectrum analyzer that used to serve me well on the higher bands. Unfortunately, the controls have got into complete disorder. It seems like one or both of the ROM's are dead. Anyone have / knows where to find ROM images of the 7L18? Thanks, Adrian From df6jb at ulrich-bangert.de Sat Nov 7 14:48:38 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Sat, 7 Nov 2009 15:48:38 +0100 Subject: [time-nuts] New version of EZGPIB Message-ID: <1EF2E03B76BC46BDBE6679BEC13D49C7@athlon> Gentlemen, a new version of EZGPIB is available. One of the biggest improvements of EZGPIB is that I have found a flawless way for communication between EZGPIB and ProfiLab. ProfiLab is a German (may be installed in English and French language too) based construction kit system for data acquisition systems that is in many aspects comparable to LABVIEW. However it has a much smaller footprint than LABVIEW, is a bit limited in it?s capabilities against LABVIEW but costs less then 100 ?!! Learn more about ProfiLab at http://www.abacom-online.de/uk/html/profilab-expert.html One of the few flaws of ProfiLab is that it does not provide GPIB communications. That makes it the ideal partner for EZGPIB which makes GPIB communication a snap. EZGPIB on the other hand lacks the rich set of graphic controls and displays that ProfiLab provides. They team up! Among other ways ProfiLab can communicate with hardware or other software by means of an ?imported DLL?. These imported DLLS appear on the working screen as a building block having a number of inputs and a number of outputs. I have written such a DLL for ProfiLab which can be configured to have 1 to 1000 inputs and 1 to 1000 outputs. Once the DLL is configured it can be connected to other ProfLab components in the usual way. Nothing more needs to be obeyed in the ProfiLab project. The counter piece to that in EZGPIB is a set of two functions named EZGPIB_ProflabOut(Output:Integer; Value:Double) and EZGPIB_ProflabIn(Input:Integer): Double which directly operate on the ProfiLab building block by means of shared memory. The ProfiLab directory contains the necessary DLL that should be copied to ProfiLab?s root directory together with it?s INI-file. The Profilab directory also includes a ProfiLab demo project that matches the EZGPIB?s ProfiLab.488 demo. A short demo AVI of EZGPIB in conjunction with ProfiLab can be found here: http://www.ulrich-bangert.de/EZGPIB_Profilab.zip The software can be downlaoded from the ususal place. Enjoy. Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener From CHJ at taconic.net Sat Nov 7 16:04:16 2009 From: CHJ at taconic.net (Christopher Hilton-Johnson) Date: Sat, 7 Nov 2009 11:04:16 -0500 Subject: [time-nuts] OT - Tek 7L18 ROM In-Reply-To: References: Message-ID: <4D62E05B511B16439FE408E5DB93985F073515@behemothus.Pchjhome.local> >Hello all, >I have an old 7L18 spectrum analyzer that used to serve me well on the >higher bands. >Unfortunately, the controls have got into complete disorder. >It seems like one or both of the ROM's are dead. >Anyone have / knows where to find ROM images of the 7L18? Adrian Can I suggest you post this to the tekscopes group - they have answers to pretty well everything Tek Having said that I do not know of any ROM images out there - I have 2 7L18s but have never got around to making ROM backups - never been able to find the ROMs to burn. Assuming it is the digital section at fault (eg no panel controllable frequency on the readout display)Several pointers; 1) If not used for a long time, the connectors, both internal and to the mainframe can go very dirty. The PI uses lots of power & needs every connector to be doing its job. Some users say remove & slam in the PI several times to help wake it up (very brave/stupid ones do it with power on) 2) digital parts can be affected by gone bad electrolytics pulling down the supplies or eg: affecting the processor reset circuit. 3) in my case the processor board had a defective RAM - no response to controls because no boot, although it would get to different stages of the boot process before halting. (Got a replacement chip from that auction house) 4) because the various sub sections/boards are so interconnected the best way to trouble shoot is to have a 2nd 7L18 (or at least a second processor board)available for board substitution. 5) you can make extenders which allow board level trouble shooting - the digital bit runs quite slowly and a logic analyzer will help if the problem lies further down the line. 6) finally, if you can back up the ROMs, I would like to place an order for a set! Chris HJ From rfnuts at arcor.de Sat Nov 7 16:49:50 2009 From: rfnuts at arcor.de (Adrian) Date: Sat, 07 Nov 2009 17:49:50 +0100 Subject: [time-nuts] OT - Tek 7L18 ROM In-Reply-To: <4D62E05B511B16439FE408E5DB93985F073515@behemothus.Pchjhome.local> References: <4D62E05B511B16439FE408E5DB93985F073515@behemothus.Pchjhome.local> Message-ID: <4AF5A52E.1060106@arcor.de> Christopher Hilton-Johnson schrieb: >> Hello all, >> > > >> I have an old 7L18 spectrum analyzer that used to serve me well on the >> higher bands. >> Unfortunately, the controls have got into complete disorder. >> It seems like one or both of the ROM's are dead. >> > > >> Anyone have / knows where to find ROM images of the 7L18? >> > > Adrian > Can I suggest you post this to the tekscopes group - they have answers > to pretty well everything Tek > Having said that I do not know of any ROM images out there - I have 2 > 7L18s but have never got around to making ROM backups - never been able > to find the ROMs to burn. > > Assuming it is the digital section at fault (eg no panel controllable > frequency on the readout display)Several pointers; > 1) If not used for a long time, the connectors, both internal and to the > mainframe can go very dirty. The PI uses lots of power & needs every > connector to be doing its job. Some users say remove & slam in the PI > several times to help wake it up (very brave/stupid ones do it with > power on) > 2) digital parts can be affected by gone bad electrolytics pulling down > the supplies or eg: affecting the processor reset circuit. > 3) in my case the processor board had a defective RAM - no response to > controls because no boot, although it would get to different stages of > the boot process before halting. (Got a replacement chip from that > auction house) > 4) because the various sub sections/boards are so interconnected the > best way to trouble shoot is to have a 2nd 7L18 (or at least a second > processor board)available for board substitution. > 5) you can make extenders which allow board level trouble shooting - the > digital bit runs quite slowly and a logic analyzer will help if the > problem lies further down the line. > 6) finally, if you can back up the ROMs, I would like to place an order > for a set! > > Chris HJ > > > Chris, thanks for the hints. I found two Tek groups, but none of them allows to read posts w/o joining. So, I can't tell which one to join. I've already tried the plugin in my special home-brew test bed, which is a parted out mainframe with the backplane board cut out.of the chassis, so I can connect the required supply voltages) while I'm working on the open plugin. Most of the front panel controls do 'something', but not what they are intended to. So, I can hear some relays clicking when I turn the span or sweep knobs, but the trace doesn't chang accordingly. Also, the ref level display is frozen, and on the center frequency display some digits are dark, though it changes in a chaotic manner when I'm turning the knob. Thus, it seems like the program is generally running, but it behaves as if the according data are totally corrupted. I could read ROM 1, but it was not stable. At least I managed to get an image that could 3...4 times be successfully compared to the ROM. ROM 2, however, contains only 'CA's, though changes into various patterns when knocked, warmed up or cooled. So, given I have some luck, ROM 1 is still alive, but ROM 2 is likely defective. Btw. I figured out that the ROM's are mostly compatible with M2716's. Just Vpp (pin 21) would have to be connected to +5V to get the M2716 running in the instrument (the origlan ROM's have pin 21 tied to GND). Adrian From alan.melia at btinternet.com Sat Nov 7 17:53:51 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Sat, 7 Nov 2009 17:53:51 -0000 Subject: [time-nuts] XKE References: <46B602966CD94AA6ABA69C6A12D49150@pascual01> Message-ID: <002c01ca5fd4$4289c0f0$0900a8c0@lark> Hi Pascual, I would be interested in a scan of any circuit diagram pages too please Thanks Alan G3NYK ----- Original Message ----- From: To: Sent: Saturday, November 07, 2009 9:31 AM Subject: [time-nuts] XKE > Hello Hubert, > I have the manual for XKE model (not the II) in german . If do you thing is similar, let me know an I will scan the pages that do you need. > > 73 > Pascual Arbona EA5JF > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From mark.amos at toast.net Sat Nov 7 19:34:38 2009 From: mark.amos at toast.net (Mark Amos) Date: Sat, 7 Nov 2009 14:34:38 -0500 Subject: [time-nuts] Calculating frequency differences using Lissajou figures Message-ID: <09994562f2ad498699f9609af723089d.mark.amos@toast.net> Time-Nuts, I recently fired up an Efratum LPRO and have been watching the slowly rotating Lissajou figure produced when comparing it's output with that of a GPSDO on a scope. It's a beautiful thing (the weather is too cool to watch paint dry...) I thought the period of "rotation" of the Lissajou figure could be used to determine the frequency difference of the two oscillators, but the math escapes me. Is it as simple as calculating the inverse of the period of the "rotation" through 360 degrees? In this case the period between in-phase and in-phase is 182 seconds yielding a rotation frequency of 5.5 mHz. So, is 5.5 mHz the frequency difference between the two 10 MHz oscillators? Or am I missing something obvious? Thanks, in advance, Mark From jpawlan at pawlan.com Sat Nov 7 19:42:56 2009 From: jpawlan at pawlan.com (Jeffrey Pawlan) Date: Sat, 7 Nov 2009 11:42:56 -0800 (PST) Subject: [time-nuts] Calculating frequency differences using Lissajou figures In-Reply-To: <09994562f2ad498699f9609af723089d.mark.amos@toast.net> References: <09994562f2ad498699f9609af723089d.mark.amos@toast.net> Message-ID: or stated in another way: your two sources differ by 5.5 parts in 10^-10 Well within the specification for the Rb. But to be precise, but if you wanted to know the absolute accuracy of the Rb then you would need to know the accuracy of the GPSDO at that moment in time. Jeffrey Pawlan From tvb at LeapSecond.com Sat Nov 7 20:18:34 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Sat, 7 Nov 2009 12:18:34 -0800 Subject: [time-nuts] Calculating frequency differences using Lissajou figures References: <09994562f2ad498699f9609af723089d.mark.amos@toast.net> Message-ID: <9953D86803BA44CEA2BF21025E621795@pc52> Mark, Your 5.5 mHz is correct for the frequency difference But note that's out of 10 MHz so the *relative* frequency error is 5.5e-3 Hz / 1e7 Hz, or 5.5e-10 (unit-less). The other way to look at it is this: The nominal frequency is 10 MHz, so one period is 100 ns. Your Lissajous pattern is seen to repeat every 182 seconds. Frequency difference is time drift over elapsed time, so the relative frequency difference is 100 ns / 182 s = 5.5e-10. --- Also, see if you can repeat this a month from now. If instead of 182 s you get, say, 188 s then you have a way to compute the frequency drift rate. 100 ns / 182 s = 5.495e-10 on November 7 100 ns / 188 s = 5.319e-10 on December 7 So your frequency drift in this example is 1.7e-11 / month. /tvb From bruce.griffiths at xtra.co.nz Sat Nov 7 20:29:06 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 08 Nov 2009 09:29:06 +1300 Subject: [time-nuts] Calculating frequency differences using Lissajou figures In-Reply-To: <9953D86803BA44CEA2BF21025E621795@pc52> References: <09994562f2ad498699f9609af723089d.mark.amos@toast.net> <9953D86803BA44CEA2BF21025E621795@pc52> Message-ID: <4AF5D892.8000900@xtra.co.nz> Tom Van Baak wrote: > Mark, > > Your 5.5 mHz is correct for the frequency difference But > note that's out of 10 MHz so the *relative* frequency error > is 5.5e-3 Hz / 1e7 Hz, or 5.5e-10 (unit-less). > > The other way to look at it is this: > > The nominal frequency is 10 MHz, so one period is 100 ns. > Your Lissajous pattern is seen to repeat every 182 seconds. > Frequency difference is time drift over elapsed time, so the > relative frequency difference is 100 ns / 182 s = 5.5e-10. > > --- > > Also, see if you can repeat this a month from now. If instead > of 182 s you get, say, 188 s then you have a way to compute > the frequency drift rate. > > 100 ns / 182 s = 5.495e-10 on November 7 > 100 ns / 188 s = 5.319e-10 on December 7 > > So your frequency drift in this example is 1.7e-11 / month. > > /tvb > Not quite, you need to take the sign of the frequency difference into account. ie in your example above the sign of the error measured on November 7 has to be identical to the sign of the error measured on December 7 for your calculation to be correct. Bruce From james.p.lux at jpl.nasa.gov Sat Nov 7 21:21:04 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Sat, 7 Nov 2009 13:21:04 -0800 Subject: [time-nuts] Calculating frequency differences using Lissajou figures In-Reply-To: <09994562f2ad498699f9609af723089d.mark.amos@toast.net> Message-ID: You got it exactly. The relative phase between the two signals (as displayed by the Lissajous) rotates one cycle in 182 seconds.. E.g. 1/182 Hz difference. On 11/7/09 11:34 AM, "Mark Amos" wrote: > Time-Nuts, > > I recently fired up an Efratum LPRO and have been watching the slowly rotating > Lissajou figure produced when comparing it's output with that of a GPSDO on a > scope. It's a > beautiful thing (the weather is too cool to watch paint dry...) > > I thought the period of "rotation" of the Lissajou figure could be used to > determine the frequency difference of the two oscillators, but the math > escapes me. > > Is it as simple as calculating the inverse of the period of the "rotation" > through 360 degrees? > > In this case the period between in-phase and in-phase is 182 seconds yielding > a rotation frequency of 5.5 mHz. So, is 5.5 mHz the frequency difference > between the two 10 MHz > oscillators? Or am I missing something obvious? > > Thanks, in advance, > > Mark > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From james.p.lux at jpl.nasa.gov Sat Nov 7 21:22:10 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Sat, 7 Nov 2009 13:22:10 -0800 Subject: [time-nuts] Calculating frequency differences using Lissajou figures In-Reply-To: <4AF5D892.8000900@xtra.co.nz> Message-ID: On 11/7/09 12:29 PM, "Bruce Griffiths" wrote: > Tom Va >> 100 ns / 182 s = 5.495e-10 on November 7 >> 100 ns / 188 s = 5.319e-10 on December 7 >> >> So your frequency drift in this example is 1.7e-11 / month. >> >> /tvb >> > Not quite, you need to take the sign of the frequency difference into > account. > ie in your example above the sign of the error measured on November 7 > has to be identical to the sign of the error measured on December 7 for > your calculation to be correct. > But the sign of the difference would be obvious from the rotation direction of the Lissajous. From johnrdore at googlemail.com Sat Nov 7 21:49:29 2009 From: johnrdore at googlemail.com (John Raymond Dore) Date: Sat, 7 Nov 2009 21:49:29 +0000 Subject: [time-nuts] R&S XKE2 Message-ID: Re: V Bonhorst request: I am that guy in Wales I have been running the R&S XSRM kit continuously using the 60KHz ferrite antenna ever since I bought it from Geoff I will hope to resolve your problem Please identify exactly the 2 sheets you require I want to obtain a R&S Digitaluhr Type CADM. Do you know where I can obtain one? "John Raymond Dor?" From hmurray at megapathdsl.net Sat Nov 7 21:50:14 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sat, 07 Nov 2009 13:50:14 -0800 Subject: [time-nuts] Calculating frequency differences using Lissajou figures In-Reply-To: Message from "Lux, Jim (337C)" of "Sat, 07 Nov 2009 13:22:10 PST." Message-ID: <20091107215015.E9F71BCFC@ip-64-139-1-69.sjc.megapath.net> >>> So your frequency drift in this example is 1.7e-11 / month. >> Not quite, you need to take the sign of the frequency >> difference into account. > But the sign of the difference would be obvious from the rotation > direction of the Lissajous. Only if you remembered to include the direction when you took the first measurement and if you connected the scope up the same way a month later. -- These are my opinions, not necessarily my employer's. I hate spam. From jltran at worldnet.att.net Sat Nov 7 23:45:38 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sat, 7 Nov 2009 17:45:38 -0600 Subject: [time-nuts] Calculating frequency differences using Lissajou figures In-Reply-To: <20091107215015.E9F71BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> And you watched it the whole time to see the 'reversal' of the rotation. Once going, it is not possible to tell 'which way' it is rotating. In other words, can you tell if it is rotating clockwise or counter clockwise? I would suggest making the GPSDO the 'trigger' for the scope and watch the LPRO on one of the input channels of the scope. If I recall correctly, if it moves left, the LPRO is high and if it moves right, it is low in frequency. Please do not quote me on this as I have had a glass of wine. After all, it's 5 o'clock somewhere. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray Sent: Saturday, November 07, 2009 3:50 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Calculating frequency differences using Lissajou figures >>> So your frequency drift in this example is 1.7e-11 / month. >> Not quite, you need to take the sign of the frequency difference into >> account. > But the sign of the difference would be obvious from the rotation > direction of the Lissajous. Only if you remembered to include the direction when you took the first measurement and if you connected the scope up the same way a month later. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From wb6bnq at cox.net Sun Nov 8 00:04:39 2009 From: wb6bnq at cox.net (WB6BNQ) Date: Sat, 07 Nov 2009 16:04:39 -0800 Subject: [time-nuts] Calculating frequency differences using Lissajou figures References: <09994562f2ad498699f9609af723089d.mark.amos@toast.net> Message-ID: <4AF60B17.D3F77613@cox.net> Mark Amos wrote: > Time-Nuts, > > snip > > In this case the period between in-phase and in-phase is 182 seconds yielding a rotation frequency of 5.5 mHz. So, is 5.5 mHz the frequency difference between the two 10 MHz > oscillators? Or am I missing something obvious? > > Thanks, in advance, > > Mark Silly question but I thought I would ask just the same. By in phase to in phase, and to make it clear, you did mean IF you selected the slant figure that went from bottom left to upper right, as the start point, that you only counted the time until it returned to the same position ? In otherwords you ignored the slant from upper left to lower right (the 180 degree position) while counting the rotation ? Bill....WB6BNQ From w6te at msn.com Sun Nov 8 00:07:57 2009 From: w6te at msn.com (David Smith) Date: Sat, 7 Nov 2009 16:07:57 -0800 Subject: [time-nuts] Calculating frequency differences using Lissajoufigures In-Reply-To: <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> References: <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> Message-ID: I'll drink to that! Dave W6TE ----- Original Message ----- From: J. L. Trantham To: 'Discussion of precise time and frequency measurement' Sent: Saturday, November 07, 2009 3:45 PM Subject: Re: [time-nuts] Calculating frequency differences using Lissajoufigures And you watched it the whole time to see the 'reversal' of the rotation. Once going, it is not possible to tell 'which way' it is rotating. In other words, can you tell if it is rotating clockwise or counter clockwise? I would suggest making the GPSDO the 'trigger' for the scope and watch the LPRO on one of the input channels of the scope. If I recall correctly, if it moves left, the LPRO is high and if it moves right, it is low in frequency. Please do not quote me on this as I have had a glass of wine. After all, it's 5 o'clock somewhere. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray Sent: Saturday, November 07, 2009 3:50 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Calculating frequency differences using Lissajou figures >>> So your frequency drift in this example is 1.7e-11 / month. >> Not quite, you need to take the sign of the frequency difference into >> account. > But the sign of the difference would be obvious from the rotation > direction of the Lissajous. Only if you remembered to include the direction when you took the first measurement and if you connected the scope up the same way a month later. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bill at iaxs.net Sun Nov 8 00:08:59 2009 From: bill at iaxs.net (Bill Hawkins) Date: Sat, 7 Nov 2009 18:08:59 -0600 Subject: [time-nuts] Calculating frequency differences using Lissajoufigures In-Reply-To: <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> References: <20091107215015.E9F71BCFC@ip-64-139-1-69.sjc.megapath.net> <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> Message-ID: <0AB667ACA96F44819A8255AF686C3187@cyrus> Well, it's 5 PM in Minneapolis, so I joined my wife on the deck to toast the vanishing sun. Didn't sing any Jimmy Buffet songs, though. But, to the matter at hand. If your Lissajous pattern scope has a Z input for intensity modulation, drive it with one of the 10 MHz sources. The direction of rotation will be obvious, as the intensified portion chases its way around the pattern. Then again, maybe you need to phase shift one of the signals 90 degrees, apply the straight and shifted versions of the same signal to X and Y so you get a circle, and then apply the other signal to the Z input. That would not be a Lissajous figure, though. You would still need to observe any changes, unless you are certain that the frequency difference will maintain the same sign. I guess that's what drives people to buy GPIB interface cards and spend hours making the whole thing work correctly. Bill Hawkins -----Original Message----- From: J. L. Trantham Sent: Saturday, November 07, 2009 5:46 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Calculating frequency differences using Lissajoufigures And you watched it the whole time to see the 'reversal' of the rotation. Once going, it is not possible to tell 'which way' it is rotating. In other words, can you tell if it is rotating clockwise or counter clockwise? I would suggest making the GPSDO the 'trigger' for the scope and watch the LPRO on one of the input channels of the scope. If I recall correctly, if it moves left, the LPRO is high and if it moves right, it is low in frequency. Please do not quote me on this as I have had a glass of wine. After all, it's 5 o'clock somewhere. Joe -----Original Message----- From: Hal Murray Sent: Saturday, November 07, 2009 3:50 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Calculating frequency differences using Lissajou figures >>> So your frequency drift in this example is 1.7e-11 / month. >> Not quite, you need to take the sign of the frequency difference into >> account. > But the sign of the difference would be obvious from the rotation > direction of the Lissajous. Only if you remembered to include the direction when you took the first measurement and if you connected the scope up the same way a month later. -- These are my opinions, not necessarily my employer's. I hate spam. From d.seiter at comcast.net Sun Nov 8 01:23:59 2009 From: d.seiter at comcast.net (d.seiter at comcast.net) Date: Sun, 8 Nov 2009 01:23:59 +0000 (UTC) Subject: [time-nuts] Efratom LPRO101 in a Tek TM500 plug-in housing? In-Reply-To: <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> Message-ID: <1873447998.5926481257643439517.JavaMail.root@sz0108a.emeryville.ca.mail.comcast.net> Has anyone built a LPRO-101 into one of these plugin housings? I'm toying with the idea, but don't want to reinvent the wheel. My biggest concern is getting rid of the heat. -Dave From mark.amos at toast.net Sun Nov 8 02:24:16 2009 From: mark.amos at toast.net (Mark Amos) Date: Sat, 7 Nov 2009 21:24:16 -0500 Subject: [time-nuts] Calculating frequency differences using Lissajou figures Message-ID: Bill, I did a two sets of measurements using different methods. In the first, I watched the two waveforms in dual trace mode. The Trimble was on channel 1 (stationary) and the LPRO was on channel 2 (slowly drifting to the left). I started timing when they were phase (Channel 1 and Channel 2 occupied the same trace), watched the LPRO waveform drift through 180 degrees out of phase and then continue until the waveforms were back in phase, at which time, I stopped the clock. In XY mode, I started timing from a right slanting diagonal (in phase), watched the form become a circle (90 degrees), saw it collapse to a left slanting diagonal (180 degrees out of phase), expand to a circle (270 degrees out) again and finally back to a right slanting diagonal (in phase), at which point I stopped the clock. The progression looked like this: /O\O/ So, my answer to your question is yes and no. Yes, I only counted the time until it returned to the same position. No, I didn't ignore the 180 degree state. Tom VB, Thanks for your calculation (100 / nS / 182 S = 5.5e-10): it feels more descriptive than the method I used. Joe, in the first experiment above, I used your suggestion (triggering on channel 1 and watching channel 2 slide to the right.) I have to think about what the drift direction means (your answer has an intuitive ring to it - moving right because the wavelength of the lower frequency is longer?) Thanks all for all of the replies. I'm afraid I've got the bug... (I found myself looking at a cesium clock on the web this afternoon.) Mark Silly question but I thought I would ask just the same. By in phase to in phase, and to make it clear, you did mean IF you selected the slant figure that went from bottom left to upper right, as the start point, that you only counted the time until it returned to the same position ? In otherwords you ignored the slant from upper left to lower right (the 180 degree position) while counting the rotation ? Bill....WB6BNQ From kilodelta4foxmike at gmail.com Sun Nov 8 02:28:07 2009 From: kilodelta4foxmike at gmail.com (Brian Kirby) Date: Sat, 07 Nov 2009 20:28:07 -0600 Subject: [time-nuts] GPS Positions Message-ID: <4AF62CB7.3040502@gmail.com> Today I had to power down my equipment and reconfigure my power feeds and UPS system to the timing station. When I brought everything back up and let it warm up, I started synchronizing my clocks to UTC via a HP Z3801A GPSDO. Somehow, one of my GPS receivers, a Motorola Oncore VP, got a trashed position and it was showing time out by 140 milliseconds. I brought up TAC32 and it showed the position was not where I surveyed it. I did not think to record the bad position and the timing error. But It gave me an idea and the un-scientific results are as follows. I set the position off on the Oncore VP by -1 minute of latitude. The time error was +1.4 uS. -3 minutes was +4.2 uS. -5 minutes was +6.8 uS. -10 minutes was +13.3 uS -30 minutes was +45.0 uS. Then I put the unit back to its referenced position and played with altitude. I really could not see any big changes until I raised the position by 500 meters, and it read +1.0 uS. At +1000 meters, it was +1.7 uS. At +5000 meters is was +9.7 uS. Brian KD4FM From dquigley at msn.com Sun Nov 8 05:29:06 2009 From: dquigley at msn.com (Dan Quigley) Date: Sat, 7 Nov 2009 21:29:06 -0800 Subject: [time-nuts] Thunderbolt/PC C# system time sync In-Reply-To: References: Message-ID: Hello - new to the list here. I am developing a c# (.net) class to encapsulate the TSIP protocol. An issue I ran across is how to accurately sync the system time running Windows with the time packets from a Thunderbolt. I've noticed that setting the OS system time with the time indicated in the TSIP primary timing report can create a noticeable accuracy difference between a PC's system time if not biased. I've compensated for that using a difference in Tick counts from the system and the time value reported by GPS. Here is the relevant code: current_time = new DateTime(stime.Year, stime.Month, stime.Day, stime.Hour, stime.Minute, stime.Second); DateTime d = DateTime.Now; // set system time once each minute if desired if ((set_system_time) && (stime.Second == 0)) { long td = (current_time.Ticks - d.Ticks) / 1000000000L; stime.Milliseconds = (short)td; // advance the clock by diff in tick count Win32.SetSystemTime(ref stime); } My question to the list is: Does anyone have experience with this issue and a better solution? Thanks in advance, Dan Quigley (N7HQ) From hudsonray at yahoo.com.au Sun Nov 8 08:44:10 2009 From: hudsonray at yahoo.com.au (Ray Hudson) Date: Sun, 8 Nov 2009 00:44:10 -0800 (PST) Subject: [time-nuts] Home NTP ? & GPS Clock s/w Message-ID: <935512.98003.qm@web65715.mail.ac4.yahoo.com> Can anyone suggest how to setup a 'home' NTP server under windows (useing WAMP or similar). This is just for use on a home LAN. Please no linux suggestions as I know they exist. Also does anyone know a good (free) GPS clock for windows (synced to com port or NTP server) Thanks Ray, VK4TFT __________________________________________________________________________________ Win 1 of 4 Sony home entertainment packs thanks to Yahoo!7. Enter now: http://au.docs.yahoo.com/homepageset/ From mccorkle at ptialaska.net Sun Nov 8 09:04:27 2009 From: mccorkle at ptialaska.net (Richard H McCorkle) Date: Sun, 8 Nov 2009 00:04:27 -0900 (AKST) Subject: [time-nuts] Home NTP ? & GPS Clock s/w In-Reply-To: <935512.98003.qm@web65715.mail.ac4.yahoo.com> References: <935512.98003.qm@web65715.mail.ac4.yahoo.com> Message-ID: <26014.206.174.20.67.1257671067.squirrel@mymail.acsalaska.net> Ray, For a simple solution with WinDoze machines take a look at Tardis 2000 at http://www.kaska.demon.co.uk as a possible approach. Tardis can get NTP time from the internet or use a GPS NEMA message to sync the time server and reboadcast NTP on your local LAN. The K9 client can be used on the other machines to keep them in sync. Its free to try with no nag screens so the price is right. Richard > > Can anyone suggest how to setup a 'home' NTP server under windows (useing WAMP or > similar). This is just for use on a home LAN. > Please no linux suggestions as I know they exist. > > Also does anyone know a good (free) GPS clock for windows (synced to com port or > NTP server) > > Thanks Ray, VK4TFT > > > __________________________________________________________________________________ > Win 1 of 4 Sony home entertainment packs thanks to Yahoo!7. > Enter now: http://au.docs.yahoo.com/homepageset/ > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From hmurray at megapathdsl.net Sun Nov 8 09:11:51 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sun, 08 Nov 2009 01:11:51 -0800 Subject: [time-nuts] Home NTP ? & GPS Clock s/w In-Reply-To: Message from Ray Hudson of "Sun, 08 Nov 2009 00:44:10 PST." <935512.98003.qm@web65715.mail.ac4.yahoo.com> Message-ID: <20091108091152.8DD79BCFC@ip-64-139-1-69.sjc.megapath.net> hudsonray at yahoo.com.au said: > Can anyone suggest how to setup a 'home' NTP server under windows > (useing WAMP or similar). This is just for use on a home LAN. I know nothing about Windows. The standard ntp package runs on windows. Meinberg compiles it and wraps it in an installer. http://www.meinberg.de/english/sw/ntp.htm > Also does anyone know a good (free) GPS clock for windows (synced to > com port or NTP server) What level of accuracy are you looking for? You can get free servers over the net. Your ISP may offer a NTP server. The pool is what most people use. http://www.pool.ntp.org/en/use.html http://support.ntp.org/bin/view/Servers/NTPPoolServers If you want better time, a local GPS clock is the usual answer. The Garmin GPS 18 is popular. Under $100, some assembly required. http://support.ntp.org/bin/view/Support/ConfiguringGarminRefclocks -- These are my opinions, not necessarily my employer's. I hate spam. From holrum at hotmail.com Sun Nov 8 15:48:11 2009 From: holrum at hotmail.com (Mark Sims) Date: Sun, 8 Nov 2009 15:48:11 +0000 Subject: [time-nuts] Efratom LPRO101 in a Tek TM500 plug-in housing? In-Reply-To: References: Message-ID: Yes, I have built one. I mounted the LPRO on an "L" shaped piece of aluminum .065 sheet the width of the LPRO. The large end of the "L" is bolted to the LPRO baseplate and TM500 prototyping module circuit board with threaded standoffs (jack screws) The small end of the "L" is bolted to the TM500 module top plate with 12 countersunk screws and thermal compound. There are two very small and thin fans mounted on the back of the TM500 circuit board on small standoffs. They blow towards the baseplate (though the holes in the prototyping board). _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/177141665/direct/01/ From glennmaillist at bellsouth.net Sun Nov 8 16:14:27 2009 From: glennmaillist at bellsouth.net (Glenn Little WB4UIV) Date: Sun, 08 Nov 2009 11:14:27 -0500 Subject: [time-nuts] Efratom LPRO101 in a Tek TM500 plug-in housing? In-Reply-To: <1873447998.5926481257643439517.JavaMail.root@sz0108a.emery ville.ca.mail.comcast.net> References: <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> <1873447998.5926481257643439517.JavaMail.root@sz0108a.emeryville.ca.mail.comcast.net> Message-ID: <6.2.3.4.2.20091108111020.04d14d80@mail.bellsouth.net> I have a PTB-100 that was made by Ball/Efratom. This is in a two wide TM-500 plugin. It is mounted in the far left slots in a TM-506 frame. If it were me, I would mount it in the far right slots and pick up power from the high power slot. This slot is also directly in front of the fan in the TM-506 frame. Just my observations from a commercial product. 73 Glenn WB4UIV At 08:23 PM 11/7/2009, you wrote: >Has anyone built a LPRO-101 into one of these plugin housings? I'm >toying with the idea, but don't want to reinvent the wheel. My >biggest concern is getting rid of the heat. > >-Dave >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From ashley40 at aol.com Sun Nov 8 16:50:01 2009 From: ashley40 at aol.com (ashley40 at aol.com) Date: Sun, 08 Nov 2009 11:50:01 -0500 Subject: [time-nuts] Trimble GPS lock light Message-ID: <8CC2EAAA5CE6834-5B8-5FEF@webmail-m007.sysops.aol.com> Hello....We're new to the list, thank you for extending membership to us ........ Question: some gps receivers mentioned here ( like the Z3801A) have a panel "lock" LED to indicate when the thing is locked onto satelites..... What about the trimble thunderbolt that is also apparently popular ? Is there some indication (other than software which we have no intention of using) of satelite lock ? Thank You Kiss-Electronics Ms Ashley Hall Cornelius, Oregon W7DUZ = From cdelect at juno.com Sun Nov 8 17:09:51 2009 From: cdelect at juno.com (Corby Dawson) Date: Sun, 8 Nov 2009 09:09:51 -0800 Subject: [time-nuts] LPRO in TM500 Message-ID: <20091108.090952.992.0.cdelect@juno.com> Dave, I have in the past installed a number of FRSC and also PRS10 into single slot TM500 modules. If I remember correctly I used a thick (about 1/8") aluminum plate most of the length of the module as the mounting and heat sink. The edge of the plate was attached to the module with screws and aluminum angle brackets to allow the top and bottom of the module to also help with the heat sinking. They all worked fine. If you use a dual wide module you will have more room to work with and maybe could used a finned heat sink. The edge connector used was one from a guy on ebay that made custom ones to use with TM500 Modules. You just screw it into place in the module using the existing holes. For power I paralleled the two 25VAC windings, fed them thru a full wave bridge into a largish capacitor, and then into a regulator set for 22VDC. The regulator is isolated with a silpad and bolted to the top frame of the module. The 10Mhz output is on the front along with a lock LED. Hope this helps. Corby Dawson ____________________________________________________________ Weight Loss Program Best Weight Loss Program - Click Here! http://thirdpartyoffers.juno.com/TGL2141/c?cp=EcIysG6hvgWbo9Au-LXB8wAAJ1ABLZFyqoH-WnHH1GJ345whAAYAAAAAAAAAAAAAAAAAAADNAAAAAAAAAAAAAAAAAAAEUgAAAAA= From kyrrin at bluefeathertech.com Sun Nov 8 17:18:10 2009 From: kyrrin at bluefeathertech.com (Bruce Lane) Date: Sun, 08 Nov 2009 09:18:10 -0800 Subject: [time-nuts] Home NTP ? & GPS Clock s/w In-Reply-To: <935512.98003.qm@web65715.mail.ac4.yahoo.com> References: <935512.98003.qm@web65715.mail.ac4.yahoo.com> Message-ID: <200911080918100702.04DD7B52@192.168.42.129> There's a windows package called NMEATime which is fairly cheap. It will accept input via serial port from just about any GPS receiver which speaks standard NMEA sentences, and it will use that to sync up the PC's clock. It will also act as an NTP time server, and it'll even generate a modulated IRIG-B signal using the system's sound card. http://www.visualgps.net/NMEATime/ Happy timing. *********** REPLY SEPARATOR *********** On 08-Nov-09 at 00:44 Ray Hudson wrote: >Can anyone suggest how to setup a 'home' NTP server under windows (useing >WAMP or similar). This is just for use on a home LAN. >Please no linux suggestions as I know they exist. > >Also does anyone know a good (free) GPS clock for windows (synced to com >port or NTP server) > >Thanks Ray, VK4TFT > > > >__________________________________________________________________________________ >Win 1 of 4 Sony home entertainment packs thanks to Yahoo!7. >Enter now: http://au.docs.yahoo.com/homepageset/ > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET NOD32 Antivirus, version of virus >signature database 4584 (20091108) __________ > >The message was checked by ESET NOD32 Antivirus. > >http://www.eset.com -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m "Quid Malmborg in Plano..." From mark at amos-family.com Sun Nov 8 17:57:39 2009 From: mark at amos-family.com (Mark Amos) Date: Sun, 8 Nov 2009 12:57:39 -0500 Subject: [time-nuts] time-nuts Digest, Vol 64, Issue 14 In-Reply-To: References: Message-ID: <014d01ca609c$f6db1cc0$e4915640$@com> Bill, et al. It's Sunday in Ohio and, as I ate my toast with the rising sun, humming along with Sibelius, I did a few more tests using your Z axis suggestion - Thanks! I tapped Channel 1 (the Trimble GPSDO) and routed its signal to the Z input. I made a recording of the pattern (two complete rotations, 720 degrees of shift.) It is stored here: I also tried tapping Channel 2 for the Z input (again, recording two complete rotations:) (These are huge files.) Using dual-trace mode on the scope, the "direction" of the LPRO sinusoid is clear compared to the stationary Trimble sinusoid (not recorded.) The when I ran these tests yesterday (measuring 182 seconds for 360 degress) it was with a homebrew GPSDO. However, subsequent runs showed poor irreproducibility of the results indicating that the homebrew unit might not a very stable source - so I switched to the Trimble for succeeding measurements, which have been very consistent. I may not have noticed the homebrew GPSDO problem if I hadn't compared it to the LPRO in these tests. Obviously, for most of you, this is pretty basic stuff, but these "visual aids" are useful for me to get an intuitive feel for the underlying phenomena. It will be interesting to watch the changes over time. Mark ---------------------------------------------------------------------- Message: 1 Date: Sat, 7 Nov 2009 18:08:59 -0600 From: "Bill Hawkins" Subject: Re: [time-nuts] Calculating frequency differences using Lissajoufigures To: "'Discussion of precise time and frequency measurement'" Message-ID: <0AB667ACA96F44819A8255AF686C3187 at cyrus> Content-Type: text/plain; charset="us-ascii" Well, it's 5 PM in Minneapolis, so I joined my wife on the deck to toast the vanishing sun. Didn't sing any Jimmy Buffet songs, though. But, to the matter at hand. If your Lissajous pattern scope has a Z input for intensity modulation, drive it with one of the 10 MHz sources. The direction of rotation will be obvious, as the intensified portion chases its way around the pattern. Then again, maybe you need to phase shift one of the signals 90 degrees, apply the straight and shifted versions of the same signal to X and Y so you get a circle, and then apply the other signal to the Z input. That would not be a Lissajous figure, though. You would still need to observe any changes, unless you are certain that the frequency difference will maintain the same sign. I guess that's what drives people to buy GPIB interface cards and spend hours making the whole thing work correctly. Bill Hawkins From mark at amos-family.com Sun Nov 8 18:15:16 2009 From: mark at amos-family.com (Mark Amos) Date: Sun, 8 Nov 2009 13:15:16 -0500 Subject: [time-nuts] time-nuts Digest, Vol 64, Issue 14 References: Message-ID: <014e01ca609f$6f65a780$4e30f680$@com> There was a typo in the message below the second recording link should be: -----Original Message----- From: Mark Amos [mailto:mark at amos-family.com] Sent: Sunday, November 08, 2009 12:58 PM To: 'time-nuts at febo.com' Subject: RE: time-nuts Digest, Vol 64, Issue 14 Bill, et al. It's Sunday in Ohio and, as I ate my toast with the rising sun, humming along with Sibelius, I did a few more tests using your Z axis suggestion - Thanks! I tapped Channel 1 (the Trimble GPSDO) and routed its signal to the Z input. I made a recording of the pattern (two complete rotations, 720 degrees of shift.) It is stored here: I also tried tapping Channel 2 for the Z input (again, recording two complete rotations:) (These are huge files.) Using dual-trace mode on the scope, the "direction" of the LPRO sinusoid is clear compared to the stationary Trimble sinusoid (not recorded.) The when I ran these tests yesterday (measuring 182 seconds for 360 degress) it was with a homebrew GPSDO. However, subsequent runs showed poor irreproducibility of the results indicating that the homebrew unit might not a very stable source - so I switched to the Trimble for succeeding measurements, which have been very consistent. I may not have noticed the homebrew GPSDO problem if I hadn't compared it to the LPRO in these tests. Obviously, for most of you, this is pretty basic stuff, but these "visual aids" are useful for me to get an intuitive feel for the underlying phenomena. It will be interesting to watch the changes over time. Mark ---------------------------------------------------------------------- Message: 1 Date: Sat, 7 Nov 2009 18:08:59 -0600 From: "Bill Hawkins" Subject: Re: [time-nuts] Calculating frequency differences using Lissajoufigures To: "'Discussion of precise time and frequency measurement'" Message-ID: <0AB667ACA96F44819A8255AF686C3187 at cyrus> Content-Type: text/plain; charset="us-ascii" Well, it's 5 PM in Minneapolis, so I joined my wife on the deck to toast the vanishing sun. Didn't sing any Jimmy Buffet songs, though. But, to the matter at hand. If your Lissajous pattern scope has a Z input for intensity modulation, drive it with one of the 10 MHz sources. The direction of rotation will be obvious, as the intensified portion chases its way around the pattern. Then again, maybe you need to phase shift one of the signals 90 degrees, apply the straight and shifted versions of the same signal to X and Y so you get a circle, and then apply the other signal to the Z input. That would not be a Lissajous figure, though. You would still need to observe any changes, unless you are certain that the frequency difference will maintain the same sign. I guess that's what drives people to buy GPIB interface cards and spend hours making the whole thing work correctly. Bill Hawkins From jfor at quik.com Sun Nov 8 18:16:18 2009 From: jfor at quik.com (J. Forster) Date: Sun, 8 Nov 2009 10:16:18 -0800 (PST) Subject: [time-nuts] Efratom LPRO101 in a Tek TM500 plug-in housing? In-Reply-To: <6.2.3.4.2.20091108111020.04d14d80@mail.bellsouth.net> References: <61AAFD8AF6644C4B817DE8C8E4E8B4F4@S0028384766> <1873447998.5926481257643439517.JavaMail.root@sz0108a.emeryville.ca.mail.comcast.net> <6.2.3.4.2.20091108111020.04d14d80@mail.bellsouth.net> Message-ID: <1791.12.6.201.91.1257704178.squirrel@popacctsnew.quik.com> Early TM500 mainframes (TM503) did not have a high power compartment. This might be the reason for Ball's design choice. -John =========== > I have a PTB-100 that was made by Ball/Efratom. This is in a two wide > TM-500 plugin. It is mounted in the far left slots in a TM-506 frame. > > If it were me, I would mount it in the far right slots and pick up > power from the high power slot. This slot is also directly in front > of the fan in the TM-506 frame. > > Just my observations from a commercial product. > > 73 > Glenn > WB4UIV > > At 08:23 PM 11/7/2009, you wrote: >>Has anyone built a LPRO-101 into one of these plugin housings? I'm >>toying with the idea, but don't want to reinvent the wheel. My >>biggest concern is getting rid of the heat. >> >>-Dave >>_______________________________________________ >>time-nuts mailing list -- time-nuts at febo.com >>To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From stanley_reynolds at yahoo.com Sun Nov 8 19:13:39 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Sun, 8 Nov 2009 11:13:39 -0800 (PST) Subject: [time-nuts] Trimble GPS lock light In-Reply-To: <8CC2EAAA5CE6834-5B8-5FEF@webmail-m007.sysops.aol.com> References: <8CC2EAAA5CE6834-5B8-5FEF@webmail-m007.sysops.aol.com> Message-ID: <883908.30935.qm@web30308.mail.mud.yahoo.com> Take a look at this: http://www.ko4bb.com/Timing/GPSMonitor/ Stanley ----- Original Message ---- From: "ashley40 at aol.com" To: time-nuts at febo.com Sent: Sun, November 8, 2009 10:50:01 AM Subject: [time-nuts] Trimble GPS lock light Hello....We're new to the list, thank you for extending membership to us ........ ? ? ? Question: some gps receivers mentioned here ( like the Z3801A) have a panel "lock" LED to indicate when the thing is locked onto satelites..... What about the trimble thunderbolt that is also apparently popular ? Is there some indication (other than software which we have no intention of using) of satelite lock ? Thank You Kiss-Electronics Ms Ashley Hall Cornelius, Oregon W7DUZ = _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Sun Nov 8 19:13:58 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 08 Nov 2009 20:13:58 +0100 Subject: [time-nuts] time-nuts Digest, Vol 64, Issue 14 In-Reply-To: <014d01ca609c$f6db1cc0$e4915640$@com> References: <014d01ca609c$f6db1cc0$e4915640$@com> Message-ID: <4AF71876.5080604@rubidium.dyndns.org> Dear Mark, Mark Amos wrote: > The when I ran these tests yesterday (measuring 182 seconds for 360 degress) > it was with a homebrew GPSDO. However, subsequent runs showed poor > irreproducibility of the results indicating that the homebrew unit might not > a very stable source - so I switched to the Trimble for succeeding > measurements, which have been very consistent. I may not have noticed the > homebrew GPSDO problem if I hadn't compared it to the LPRO in these tests. > > Obviously, for most of you, this is pretty basic stuff, but these "visual > aids" are useful for me to get an intuitive feel for the underlying > phenomena. > > It will be interesting to watch the changes over time. Recall that 1/f types of noises does not average well over time, so there will be some walking around in phase. All to keep us on our toes a little more. It is natural of feedback oscillators. Cheers, Magnus From didier at cox.net Mon Nov 9 01:01:00 2009 From: didier at cox.net (Didier Juges) Date: Sun, 8 Nov 2009 19:01:00 -0600 Subject: [time-nuts] Trimble GPS lock light In-Reply-To: <883908.30935.qm@web30308.mail.mud.yahoo.com> References: <8CC2EAAA5CE6834-5B8-5FEF@webmail-m007.sysops.aol.com> <883908.30935.qm@web30308.mail.mud.yahoo.com> Message-ID: > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Stanley Reynolds > Sent: Sunday, November 08, 2009 1:14 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Trimble GPS lock light > > Take a look at this: > http://www.ko4bb.com/Timing/GPSMonitor/ > > Stanley > > > ----- Original Message ---- > From: "ashley40 at aol.com" > To: time-nuts at febo.com > Sent: Sun, November 8, 2009 10:50:01 AM > Subject: [time-nuts] Trimble GPS lock light > > > Hello....We're new to the list, thank you for extending > membership to us ........ > ? ? ? Question: some gps receivers mentioned here ( like the > Z3801A) have a panel "lock" LED to indicate when the thing is > locked onto satelites..... What about the trimble thunderbolt > that is also apparently popular ? Is there some indication > (other than software which we have no intention of using) of > satelite lock ? > > Thank You > Kiss-Electronics > Ms Ashley Hall > Cornelius, Oregon > > > W7DUZ > = > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From didier at cox.net Mon Nov 9 01:06:38 2009 From: didier at cox.net (Didier Juges) Date: Sun, 8 Nov 2009 19:06:38 -0600 Subject: [time-nuts] Trimble GPS lock light In-Reply-To: <883908.30935.qm@web30308.mail.mud.yahoo.com> References: <8CC2EAAA5CE6834-5B8-5FEF@webmail-m007.sysops.aol.com> <883908.30935.qm@web30308.mail.mud.yahoo.com> Message-ID: <2F7B6192BE434518A1C7873686EF8EFD@d400> Regarding the GPS Monitor, I have received a couple of requests for an LED indicating lock. That is easy to do, but I am fairly busy at the moment (a deadline by Thanksgiving, if I am done by then...) So if you want me to do it, it will probably be around Christmas before I have much time at all. Alternately, the software is available, it uses the free SDCC compiler and the free Silabs IDE, all you need is a Silabs JTAG adapter, which can be bought for about $25 or so (debug adapter and toolstick base) and you can write/modify the software. If anyone feels like playing with it, send me an email. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Stanley Reynolds > Sent: Sunday, November 08, 2009 1:14 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Trimble GPS lock light > > Take a look at this: > http://www.ko4bb.com/Timing/GPSMonitor/ > > Stanley > > > ----- Original Message ---- > From: "ashley40 at aol.com" > To: time-nuts at febo.com > Sent: Sun, November 8, 2009 10:50:01 AM > Subject: [time-nuts] Trimble GPS lock light > > > Hello....We're new to the list, thank you for extending > membership to us ........ > ? ? ? Question: some gps receivers mentioned here ( like the > Z3801A) have a panel "lock" LED to indicate when the thing is > locked onto satelites..... What about the trimble thunderbolt > that is also apparently popular ? Is there some indication > (other than software which we have no intention of using) of > satelite lock ? > > Thank You > Kiss-Electronics > Ms Ashley Hall > Cornelius, Oregon > > > W7DUZ > = > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From w1ksz at earthlink.net Mon Nov 9 01:39:01 2009 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Sun, 8 Nov 2009 20:39:01 -0500 (EST) Subject: [time-nuts] Trimble GPS lock light Message-ID: <20297731.1257730742037.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> Here is a "lock" indicator that I incorporated into the N1JEZ GPSDO I built. Not sure if it can be used on the T-Bolt or not. Don't see why it cannot be used. 73, Dick, W1KSZ http://www.ham-radio.com/wa6vhs/GPS/3DFix%20LED%20only%20with%20pics%20_4_.pdf -----Original Message----- >From: Didier Juges >Sent: Nov 8, 2009 8:01 PM >To: 'Discussion of precise time and frequency measurement' >Subject: Re: [time-nuts] Trimble GPS lock light > > > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Stanley Reynolds >> Sent: Sunday, November 08, 2009 1:14 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Trimble GPS lock light >> >> Take a look at this: >> http://www.ko4bb.com/Timing/GPSMonitor/ >> >> Stanley >> >> >> ----- Original Message ---- >> From: "ashley40 at aol.com" >> To: time-nuts at febo.com >> Sent: Sun, November 8, 2009 10:50:01 AM >> Subject: [time-nuts] Trimble GPS lock light >> >> >> Hello....We're new to the list, thank you for extending >> membership to us ........ >> ? ? ? Question: some gps receivers mentioned here ( like the >> Z3801A) have a panel "lock" LED to indicate when the thing is >> locked onto satelites..... What about the trimble thunderbolt >> that is also apparently popular ? Is there some indication >> (other than software which we have no intention of using) of >> satelite lock ? >> >> Thank You >> Kiss-Electronics >> Ms Ashley Hall >> Cornelius, Oregon >> >> >> W7DUZ >> = >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, >> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, >> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From didier at cox.net Mon Nov 9 02:21:09 2009 From: didier at cox.net (Didier Juges) Date: Sun, 8 Nov 2009 20:21:09 -0600 Subject: [time-nuts] Trimble GPS lock light In-Reply-To: <20297731.1257730742037.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> References: <20297731.1257730742037.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> Message-ID: The Thunderbolt sends TSIP messages, not NMEA messages. If your "lock" indicator understands the TSIP protocol, then of course it will work. Otherwise, probably not. From the pdf file you included in your message, it looks like it is NMEA only. The TSIP protocol is not complicated (just slightly more so than NMEA messages because of the escape sequences), and all the details can be found on the TSIP spec from Trimble, or if you just want the basics, you can use the decoder I wrote for my GPS Monitor project. It's open source. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Richard W. Solomon > Sent: Sunday, November 08, 2009 7:39 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Trimble GPS lock light > > Here is a "lock" indicator that I incorporated into the N1JEZ > GPSDO I built. Not sure if it can be used on the T-Bolt or not. > Don't see why it cannot be used. > > 73, Dick, W1KSZ > > http://www.ham-radio.com/wa6vhs/GPS/3DFix%20LED%20only%20with% > 20pics%20_4_.pdf > > -----Original Message----- > >From: Didier Juges > >Sent: Nov 8, 2009 8:01 PM > >To: 'Discussion of precise time and frequency measurement' > > > >Subject: Re: [time-nuts] Trimble GPS lock light > > > > > > > >> -----Original Message----- > >> From: time-nuts-bounces at febo.com > >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Stanley Reynolds > >> Sent: Sunday, November 08, 2009 1:14 PM > >> To: Discussion of precise time and frequency measurement > >> Subject: Re: [time-nuts] Trimble GPS lock light > >> > >> Take a look at this: > >> http://www.ko4bb.com/Timing/GPSMonitor/ > >> > >> Stanley > >> > >> > >> ----- Original Message ---- > >> From: "ashley40 at aol.com" > >> To: time-nuts at febo.com > >> Sent: Sun, November 8, 2009 10:50:01 AM > >> Subject: [time-nuts] Trimble GPS lock light > >> > >> > >> Hello....We're new to the list, thank you for extending > membership to > >> us ........ > >> ? ? ? Question: some gps receivers mentioned here ( like the > >> Z3801A) have a panel "lock" LED to indicate when the thing > is locked > >> onto satelites..... What about the trimble thunderbolt > that is also > >> apparently popular ? Is there some indication (other than software > >> which we have no intention of using) of satelite lock ? > >> > >> Thank You > >> Kiss-Electronics > >> Ms Ashley Hall > >> Cornelius, Oregon > >> > >> > >> W7DUZ > >> = > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > > > > >_______________________________________________ > >time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to > >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From dave at uk-ar.co.uk Mon Nov 9 11:08:06 2009 From: dave at uk-ar.co.uk (Dave Baxter) Date: Mon, 9 Nov 2009 11:08:06 -0000 Subject: [time-nuts] OT - Tek 7L18 ROM Message-ID: If no one else has said this. Check the mainframe power supplies. The 7L18 is a thirsty beast. If anyone can back up the rom images, well done. It's one of the "classic" machines internally driven by the "Original" microprocessor, the Intel 4004! The Rom's will be of a similar vintage, multi rail supplies etc I suspect. (I've only ever seen one other instrument that used a i4004 CPU, a Finnegan GC oven!) As below, get on the TekScopes list for more info. TekScopes at yahoogroups.com is the one to go for. Someone has also started a Microwave equipment group too. http://groups.yahoo.com/group/MicroWaveandTestEquipTrader/ Again, you need to subscribe to even see the messages, a spam reduction precaution, sadly. Regards. Dave B. An ex Tek(UK) employee, who used to work on 7Lxx's in the past. ---- Original Message ---- >Hello all, >I have an old 7L18 spectrum analyzer that used to serve me well on the >higher bands. >Unfortunately, the controls have got into complete disorder. >It seems like one or both of the ROM's are dead. >Anyone have / knows where to find ROM images of the 7L18? Adrian Can I suggest you post this to the tekscopes group - they have answers to pretty well everything Tek Having said that I do not know of any ROM images out there - I have 2 7L18s but have never got around to making ROM backups - never been able to find the ROMs to burn. Assuming it is the digital section at fault (eg no panel controllable frequency on the readout display)Several pointers; 1) If not used for a long time, the connectors, both internal and to the mainframe can go very dirty. The PI uses lots of power & needs every connector to be doing its job. Some users say remove & slam in the PI several times to help wake it up (very brave/stupid ones do it with power on) 2) digital parts can be affected by gone bad electrolytics pulling down the supplies or eg: affecting the processor reset circuit. 3) in my case the processor board had a defective RAM - no response to controls because no boot, although it would get to different stages of the boot process before halting. (Got a replacement chip from that auction house) 4) because the various sub sections/boards are so interconnected the best way to trouble shoot is to have a 2nd 7L18 (or at least a second processor board)available for board substitution. 5) you can make extenders which allow board level trouble shooting - the digital bit runs quite slowly and a logic analyzer will help if the problem lies further down the line. 6) finally, if you can back up the ROMs, I would like to place an order for a set! Chris HJ From cfharris at erols.com Mon Nov 9 13:12:54 2009 From: cfharris at erols.com (Chuck Harris) Date: Mon, 09 Nov 2009 08:12:54 -0500 Subject: [time-nuts] OT - Tek 7L18 ROM In-Reply-To: References: Message-ID: <4AF81556.80806@erols.com> Hi Dave, That is an issue that needs to be re-emphasized. You can't read the EPROMS in a 7L18 without using multiple rail supplies. +5V alone won't do it. Also, the 7L18 draws too much power for any of the 4 slot scopes. In spite of what the manual says, It is designed to operate in one frame only, the 7603. The biggest problem I found with mine was the tantalum electrolytic caps on the mother board kept failing. Also there are a pair of shottky RF diodes being used as +/- 15V power supply isolation diodes on the YIG oscillator that fail, killing the phase lock capabilities. They need to be replaced with some real diodes ;-) -Chuck Harris Dave Baxter wrote: > If no one else has said this. > > Check the mainframe power supplies. The 7L18 is a thirsty beast. > > If anyone can back up the rom images, well done. It's one of the > "classic" machines internally driven by the "Original" microprocessor, > the Intel 4004! The Rom's will be of a similar vintage, multi rail > supplies etc I suspect. > > (I've only ever seen one other instrument that used a i4004 CPU, a > Finnegan GC oven!) From jfor at quik.com Mon Nov 9 15:35:30 2009 From: jfor at quik.com (J. Forster) Date: Mon, 9 Nov 2009 07:35:30 -0800 (PST) Subject: [time-nuts] OT - Tek 7L18 ROM In-Reply-To: References: Message-ID: <1108.12.6.201.237.1257780930.squirrel@popacctsnew.quik.com> There is also a Tekscopes2 at Yahoogroups.com which is a LOT more tolerant of random questions. -John ================ > As below, get on the TekScopes list for more info. > TekScopes at yahoogroups.com is the one to go for. > > Someone has also started a Microwave equipment group too. > http://groups.yahoo.com/group/MicroWaveandTestEquipTrader/ > > Again, you need to subscribe to even see the messages, a spam reduction > precaution, sadly. > > > Regards. > > Dave B. > An ex Tek(UK) employee, who used to work on 7Lxx's in the past. > > > ---- Original Message ---- > >>Hello all, >>I have an old 7L18 spectrum analyzer that used to serve me well on the >>higher bands. >>Unfortunately, the controls have got into complete disorder. >>It seems like one or both of the ROM's are dead. > >>Anyone have / knows where to find ROM images of the 7L18? > > Adrian > Can I suggest you post this to the tekscopes group - they have answers > to pretty well everything Tek Having said that I do not know of any ROM > images out there - I have 2 7L18s but have never got around to making > ROM backups - never been able to find the ROMs to burn. > > Assuming it is the digital section at fault (eg no panel controllable > frequency on the readout display)Several pointers; > 1) If not used for a long time, the connectors, both internal and to the > mainframe can go very dirty. The PI uses lots of power & needs every > connector to be doing its job. Some users say remove & slam in the PI > several times to help wake it up (very brave/stupid ones do it with > power on) > 2) digital parts can be affected by gone bad electrolytics pulling down > the supplies or eg: affecting the processor reset circuit. > 3) in my case the processor board had a defective RAM - no response to > controls because no boot, although it would get to different stages of > the boot process before halting. (Got a replacement chip from that > auction house) > 4) because the various sub sections/boards are so interconnected the > best way to trouble shoot is to have a 2nd 7L18 (or at least a second > processor board)available for board substitution. > 5) you can make extenders which allow board level trouble shooting - the > digital bit runs quite slowly and a logic analyzer will help if the > problem lies further down the line. > 6) finally, if you can back up the ROMs, I would like to place an order > for a set! > > Chris HJ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From didier at cox.net Mon Nov 9 15:45:28 2009 From: didier at cox.net (Didier Juges) Date: Mon, 9 Nov 2009 15:45:28 +0000 Subject: [time-nuts] OT - Tek 7L18 ROM In-Reply-To: <4AF81556.80806@erols.com> References: <4AF81556.80806@erols.com> Message-ID: <427206584-1257781513-cardhu_decombobulator_blackberry.rim.net-522547347-@bda224.bisx.prod.on.blackberry> My 7L18 only works in my 7704, and not in any of the two 3 slots mainframes 7603 I had at one time... Maybe the 7603 were defective (they worked with regular plugins at the time, but both developed ps problems soon thereafter), but the 7L18 works fine in the 7704, even with another vertical amplifier plugged in the empty slot. I had a picture of it on my web site, but it seems like it did not survive the last cleaning... Didier ------------------------ Sent from my BlackBerry Wireless thingy while I do other things... -----Original Message----- From: Chuck Harris Date: Mon, 09 Nov 2009 08:12:54 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT - Tek 7L18 ROM Hi Dave, That is an issue that needs to be re-emphasized. You can't read the EPROMS in a 7L18 without using multiple rail supplies. +5V alone won't do it. Also, the 7L18 draws too much power for any of the 4 slot scopes. In spite of what the manual says, It is designed to operate in one frame only, the 7603. The biggest problem I found with mine was the tantalum electrolytic caps on the mother board kept failing. Also there are a pair of shottky RF diodes being used as +/- 15V power supply isolation diodes on the YIG oscillator that fail, killing the phase lock capabilities. They need to be replaced with some real diodes ;-) -Chuck Harris Dave Baxter wrote: > If no one else has said this. > > Check the mainframe power supplies. The 7L18 is a thirsty beast. > > If anyone can back up the rom images, well done. It's one of the > "classic" machines internally driven by the "Original" microprocessor, > the Intel 4004! The Rom's will be of a similar vintage, multi rail > supplies etc I suspect. > > (I've only ever seen one other instrument that used a i4004 CPU, a > Finnegan GC oven!) _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From 4z5cp at bezeqint.net Mon Nov 9 16:09:18 2009 From: 4z5cp at bezeqint.net (Dimitry Borzenko) Date: Mon, 9 Nov 2009 18:09:18 +0200 Subject: [time-nuts] Gigatronics 610 ROM Images. Message-ID: <075BA20296534CF491490A6BD9537081@Doctor> Hello guys. May be this wrong mail list, but I ask my question and if anyone knows right mail list please lets me know. I have Gigatronics 610 (0.01-8GHz) sweeper with ROM v.4 and have problem with HP emulation (this sweeper has HP commands set and responds as 08340 for dedicated systems). To enable HP commands set I must to send via GPIB command "HP", but after recycling power I need to do this again, so this way is not good for dedicated systems. May be someone have newer firmware version? Thanks, and Best Regards. From jfor at quik.com Mon Nov 9 16:27:22 2009 From: jfor at quik.com (J. Forster) Date: Mon, 9 Nov 2009 08:27:22 -0800 (PST) Subject: [time-nuts] Gigatronics 610 ROM Images. In-Reply-To: <075BA20296534CF491490A6BD9537081@Doctor> References: <075BA20296534CF491490A6BD9537081@Doctor> Message-ID: <1361.12.6.201.237.1257784042.squirrel@popacctsnew.quik.com> Just a thought: Does the unit remember the last used setting after a power cycle? If not, and the manual says it should, maybe it has a bad parameter RAM battery. That's a common problem with older instruments. FWIW, -John ============== > Hello guys. > May be this wrong mail list, but I ask my question and if anyone knows > right > mail list please lets me know. > > I have Gigatronics 610 (0.01-8GHz) sweeper with ROM v.4 and have problem > with HP emulation (this sweeper has HP commands set and responds as 08340 > for dedicated systems). > To enable HP commands set I must to send via GPIB command "HP", but after > recycling power I need to do this again, so this way is not good for > dedicated systems. > > May be someone have newer firmware version? > > Thanks, and Best Regards. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From rfnuts at arcor.de Mon Nov 9 16:52:02 2009 From: rfnuts at arcor.de (Adrian) Date: Mon, 09 Nov 2009 17:52:02 +0100 Subject: [time-nuts] OT - Tek 7L18 ROM In-Reply-To: <427206584-1257781513-cardhu_decombobulator_blackberry.rim.net-522547347-@bda224.bisx.prod.on.blackberry> References: <4AF81556.80806@erols.com> <427206584-1257781513-cardhu_decombobulator_blackberry.rim.net-522547347-@bda224.bisx.prod.on.blackberry> Message-ID: <4AF848B2.8040309@arcor.de> Didier, my 7L18 has been working fine in a 7603. As by the catalog, it is compatible with any of the 7000 mainframes. And, in the '82 catalog, the 7603 is suggested. Btw. both MC schematics show a single +5V supply. The believed to be early schematic shows 6 ea. 512 x 8 ROM's, while the more recent one that matches my 7L18 has two 2048 x 8 ROM's. Mine appears to be from 1978. It's not listed in the 1977 catalog, but I have a product folder from 1977 introducing the new 7L18 :) There is also a 1977 plug-in catalog with a note saying that it is currently available in the US and Canada, and that it will be available in other areas of the world in the first quarter of 1978. Many thanks for all off the help. I hope to find a ROM image at a time. Adrian Didier Juges schrieb: > My 7L18 only works in my 7704, and not in any of the two 3 slots mainframes 7603 I had at one time... Maybe the 7603 were defective (they worked with regular plugins at the time, but both developed ps problems soon thereafter), but the 7L18 works fine in the 7704, even with another vertical amplifier plugged in the empty slot. > > I had a picture of it on my web site, but it seems like it did not survive the last cleaning... > > Didier > > ------------------------ Sent from my BlackBerry Wireless thingy while I do other things... > > -----Original Message----- > From: Chuck Harris > Date: Mon, 09 Nov 2009 08:12:54 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] OT - Tek 7L18 ROM > > Hi Dave, > > That is an issue that needs to be re-emphasized. You can't read > the EPROMS in a 7L18 without using multiple rail supplies. +5V > alone won't do it. > > Also, the 7L18 draws too much power for any of the 4 slot scopes. > In spite of what the manual says, It is designed to operate in one > frame only, the 7603. > > The biggest problem I found with mine was the tantalum electrolytic > caps on the mother board kept failing. Also there are a pair of > shottky RF diodes being used as +/- 15V power supply isolation diodes on > the YIG oscillator that fail, killing the phase lock capabilities. > They need to be replaced with some real diodes ;-) > > -Chuck Harris > > Dave Baxter wrote: > >> If no one else has said this. >> >> Check the mainframe power supplies. The 7L18 is a thirsty beast. >> >> If anyone can back up the rom images, well done. It's one of the >> "classic" machines internally driven by the "Original" microprocessor, >> the Intel 4004! The Rom's will be of a similar vintage, multi rail >> supplies etc I suspect. >> >> (I've only ever seen one other instrument that used a i4004 CPU, a >> Finnegan GC oven!) >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From CHJ at taconic.net Mon Nov 9 19:50:09 2009 From: CHJ at taconic.net (Christopher Hilton-Johnson) Date: Mon, 9 Nov 2009 14:50:09 -0500 Subject: [time-nuts] OT - Tek 7L18 ROM In-Reply-To: References: Message-ID: <4D62E05B511B16439FE408E5DB93985F073523@behemothus.Pchjhome.local> Chuck Harris wrote; >That is an issue that needs to be re-emphasized. You can't read >the EPROMS in a 7L18 without using multiple rail supplies. +5V >alone won't do it. The ROMS in the -01 version of the micro board are MCM68316E and are 5v items. >Also, the 7L18 draws too much power for any of the 4 slot scopes. >In spite of what the manual says, It is designed to operate in one >frame only, the 7603. May be so, but both my 7L18s work happily in 4 slot mainframes & on flexible extenders as well, either with or without another PI in the left most compartment. All contacts must be clean though & no dicky tantalums etc. >The biggest problem I found with mine was the tantalum electrolytic >caps on the mother board kept failing. Also there are a pair of >shottky RF diodes being used as +/- 15V power supply isolation diodes on >the YIG oscillator that fail, killing the phase lock capabilities. >They need to be replaced with some real diodes ;-) Oh yes indeed, and in many of the other sub assemblies as well eg PLL for a start. Chris HJ From paulswedb at gmail.com Mon Nov 9 20:58:40 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 9 Nov 2009 15:58:40 -0500 Subject: [time-nuts] Calculating frequency differences using Lissajou figures In-Reply-To: References: Message-ID: With Loran C shutting down in Jan, curious if anyone still uses it. I have a z3801 but always liked the Austrons 2100s as another way to check everything. I pulled the old Gertch RLF-1 out of the basement and it still works. (retired it 9 years ago) But a far cry from the Loran chains accuracy and ease of use. Curious what might be the next reference?? Thanks From alan.melia at btinternet.com Mon Nov 9 21:44:53 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 9 Nov 2009 21:44:53 -0000 Subject: [time-nuts] Calculating frequency differences using Lissajoufigures (paulswed) References: Message-ID: <000101ca6186$4429c320$0900a8c0@lark> Hi Paul there is a bad case of subject theft here which makes life difficult for searches!! I have had to continue in the hope you seethis message. Do you actually have a definitive statement that Loran-C is closing.?? there is nothing on the USCG or the Megapulse sites. Though there is comment from the Feb 09 budget statement, but not definite close statement.....rather like NOAA SEC the other year. Alan G3NYK ----- Original Message ----- From: "paul swed" To: "What next after loran shuts down?" Sent: Monday, November 09, 2009 8:58 PM Subject: Re: [time-nuts] Calculating frequency differences using Lissajoufigures > With Loran C shutting down in Jan, curious if anyone still uses it. > I have a z3801 but always liked the Austrons 2100s as another way to check > everything. > I pulled the old Gertch RLF-1 out of the basement and it still works. > (retired it 9 years ago) > But a far cry from the Loran chains accuracy and ease of use. > Curious what might be the next reference?? > Thanks > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From paulswedb at gmail.com Mon Nov 9 21:48:15 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 9 Nov 2009 16:48:15 -0500 Subject: [time-nuts] Anyone have a Tracor 599h manual? Message-ID: Looking to modify a low freq to 60 wwvb. Thanks From EWKehren at aol.com Mon Nov 9 22:00:38 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 9 Nov 2009 17:00:38 EST Subject: [time-nuts] Anyone have a Tracor 599h manual? Message-ID: I have a manual and I have modified several to 60 KHz. All you have to do is change the Synthesizer. Where are you located. I can mail it to you and you return it with reimbursement of my shipping expenses. By the way Tracor did have a down converter. Bert Kehren Miami In a message dated 11/9/2009 4:48:49 P.M. Eastern Standard Time, paulswedb at gmail.com writes: Looking to modify a low freq to 60 wwvb. Thanks _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From paulswedb at gmail.com Mon Nov 9 22:01:25 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 9 Nov 2009 17:01:25 -0500 Subject: [time-nuts] LORAN C shutdown Message-ID: Alan Very sorry if I grabbed your thread. I thought I changed the header I finally found it in the senate votes this weekend. The house and senate voted to shut it down and the president signed it. (We will save .00002% of the budget) The USCG and DHS said they had no need. It was very hard to find, its not on the uscg or megapulse site Changed the header but maybe you can't start threads that way. I sure would like to be very very wrong on this subject. Regards Paul. PS one day I will figure out why the reply says me From brooke at pacific.net Mon Nov 9 22:09:22 2009 From: brooke at pacific.net (Brooke Clarke) Date: Mon, 09 Nov 2009 14:09:22 -0800 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: Message-ID: <4AF89312.4000407@pacific.net> Hi: It's here: http://www.navcen.uscg.gov/Loran/default.htm under: The Operating Status of LORAN-C Have Fun, Brooke Clarke http://www.prc68.com paul swed wrote: > Alan > Very sorry if I grabbed your thread. I thought I changed the header > > I finally found it in the senate votes this weekend. > The house and senate voted to shut it down and the president signed it. > (We will save .00002% of the budget) > The USCG and DHS said they had no need. > It was very hard to find, its not on the uscg or megapulse site > > Changed the header but maybe you can't start threads that way. > I sure would like to be very very wrong on this subject. > > Regards > Paul. > PS one day I will figure out why the reply says me > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From rdarlington at gmail.com Mon Nov 9 22:10:22 2009 From: rdarlington at gmail.com (Robert Darlington) Date: Mon, 9 Nov 2009 15:10:22 -0700 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: Message-ID: Anybody looking to buy an Austron 2000c ? Any takers? Any? -Bob On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > Alan > Very sorry if I grabbed your thread. I thought I changed the header > > I finally found it in the senate votes this weekend. > The house and senate voted to shut it down and the president signed it. > (We will save .00002% of the budget) > The USCG and DHS said they had no need. > It was very hard to find, its not on the uscg or megapulse site > > Changed the header but maybe you can't start threads that way. > I sure would like to be very very wrong on this subject. > > Regards > Paul. > PS one day I will figure out why the reply says me > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jfor at quik.com Mon Nov 9 22:14:25 2009 From: jfor at quik.com (J. Forster) Date: Mon, 9 Nov 2009 14:14:25 -0800 (PST) Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: Message-ID: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. See: http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf -John =============== > Anybody looking to buy an Austron 2000c ? Any takers? Any? > > > -Bob > > On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > >> Alan >> Very sorry if I grabbed your thread. I thought I changed the header >> >> I finally found it in the senate votes this weekend. >> The house and senate voted to shut it down and the president signed it. >> (We will save .00002% of the budget) >> The USCG and DHS said they had no need. >> It was very hard to find, its not on the uscg or megapulse site >> >> Changed the header but maybe you can't start threads that way. >> I sure would like to be very very wrong on this subject. >> >> Regards >> Paul. >> PS one day I will figure out why the reply says me >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From garnere at gmail.com Mon Nov 9 22:25:56 2009 From: garnere at gmail.com (Eric Garner) Date: Mon, 9 Nov 2009 14:25:56 -0800 Subject: [time-nuts] LORAN C shutdown In-Reply-To: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: So what are ships/planes supposed to if/when satellite navigation becomes unreliable or unavailable ? On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. > > See: > > http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf > > -John > > =============== > > > >> Anybody looking to buy an Austron 2000c ? ? Any takers? ?Any? >> >> >> -Bob >> >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: >> >>> Alan >>> ? ?Very sorry if I grabbed your thread. I thought I changed the header >>> >>> I finally found it in the senate votes this weekend. >>> The house and senate voted to shut it down and the president signed it. >>> (We will save .00002% of the budget) >>> The USCG and DHS said they had no need. >>> It was very hard to find, its not on the uscg or megapulse site >>> >>> Changed the header but maybe you can't start threads that way. >>> I sure would like to be very very wrong on this subject. >>> >>> Regards >>> Paul. >>> PS one day I will figure out why the reply says me >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- --Eric _________________________________________ Eric Garner From magnus at rubidium.dyndns.org Mon Nov 9 22:31:00 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 09 Nov 2009 23:31:00 +0100 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: Message-ID: <4AF89824.5010702@rubidium.dyndns.org> Hi Paul! paul swed wrote: > Alan > Very sorry if I grabbed your thread. I thought I changed the header > > I finally found it in the senate votes this weekend. > The house and senate voted to shut it down and the president signed it. > (We will save .00002% of the budget) > The USCG and DHS said they had no need. > It was very hard to find, its not on the uscg or megapulse site > > Changed the header but maybe you can't start threads that way. > I sure would like to be very very wrong on this subject. A good overview is most probably that of http://pnt.gov/policy/legislation/bills.shtml#loran PNT.gov has other material on the fiscal aspects of GPS, support systems etc. http://pnt.gov/congress/ By the look of things it goes silent as of 2010-01-04: http://www.gpsworld.com/gnss-system/news/administration-ax-falls-pnt-backup-loran-c-9087 The situation in Europe might be different. Cheers, Magnus From 4z5cp at bezeqint.net Mon Nov 9 22:37:27 2009 From: 4z5cp at bezeqint.net (Dimitry Borzenko) Date: Tue, 10 Nov 2009 00:37:27 +0200 Subject: [time-nuts] Gigatronics 610 ROM Images. In-Reply-To: <1361.12.6.201.237.1257784042.squirrel@popacctsnew.quik.com> Message-ID: Hello John. Thanks, unit is remembering last setting, and has 9 memories; problem is not in memory or RAMS battery. Regards. -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster Sent: Monday, November 09, 2009 6:27 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Gigatronics 610 ROM Images. Just a thought: Does the unit remember the last used setting after a power cycle? If not, and the manual says it should, maybe it has a bad parameter RAM battery. That's a common problem with older instruments. FWIW, -John ============== > Hello guys. > May be this wrong mail list, but I ask my question and if anyone knows > right > mail list please lets me know. > > I have Gigatronics 610 (0.01-8GHz) sweeper with ROM v.4 and have problem > with HP emulation (this sweeper has HP commands set and responds as 08340 > for dedicated systems). > To enable HP commands set I must to send via GPIB command "HP", but after > recycling power I need to do this again, so this way is not good for > dedicated systems. > > May be someone have newer firmware version? > > Thanks, and Best Regards. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From EWKehren at aol.com Mon Nov 9 22:40:36 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 9 Nov 2009 17:40:36 EST Subject: [time-nuts] LORAN C shutdown Message-ID: There can be life for many Loran C receivers. They can be used as a high resolution comparator with a Loran C simulator that could be made with a few components and a PIC. Bert Kehren In a message dated 11/9/2009 5:11:02 P.M. Eastern Standard Time, rdarlington at gmail.com writes: Anybody looking to buy an Austron 2000c ? Any takers? Any? -Bob On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > Alan > Very sorry if I grabbed your thread. I thought I changed the header > > I finally found it in the senate votes this weekend. > The house and senate voted to shut it down and the president signed it. > (We will save .00002% of the budget) > The USCG and DHS said they had no need. > It was very hard to find, its not on the uscg or megapulse site > > Changed the header but maybe you can't start threads that way. > I sure would like to be very very wrong on this subject. > > Regards > Paul. > PS one day I will figure out why the reply says me > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From msa at latt.net Mon Nov 9 22:42:43 2009 From: msa at latt.net (Majdi S. Abbas) Date: Mon, 9 Nov 2009 15:42:43 -0700 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: <20091109224243.GA55802@puck.nether.net> On Mon, Nov 09, 2009 at 02:25:56PM -0800, Eric Garner wrote: > So what are ships/planes supposed to if/when satellite navigation > becomes unreliable or unavailable ? Well, the government is still publishing the almanac. I guess it's time for us to dig up our sextants and take some practice sightings. --msa From paulswedb at gmail.com Mon Nov 9 22:43:22 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 9 Nov 2009 17:43:22 -0500 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: I believe sextant On Mon, Nov 9, 2009 at 5:25 PM, Eric Garner wrote: > So what are ships/planes supposed to if/when satellite navigation > becomes unreliable or unavailable ? > > > On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: > > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. > > > > See: > > > > > http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf > > > > -John > > > > =============== > > > > > > > >> Anybody looking to buy an Austron 2000c ? Any takers? Any? > >> > >> > >> -Bob > >> > >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > >> > >>> Alan > >>> Very sorry if I grabbed your thread. I thought I changed the header > >>> > >>> I finally found it in the senate votes this weekend. > >>> The house and senate voted to shut it down and the president signed it. > >>> (We will save .00002% of the budget) > >>> The USCG and DHS said they had no need. > >>> It was very hard to find, its not on the uscg or megapulse site > >>> > >>> Changed the header but maybe you can't start threads that way. > >>> I sure would like to be very very wrong on this subject. > >>> > >>> Regards > >>> Paul. > >>> PS one day I will figure out why the reply says me > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts at febo.com > >>> To unsubscribe, go to > >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > --Eric > _________________________________________ > Eric Garner > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From magnus at rubidium.dyndns.org Mon Nov 9 22:44:04 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 09 Nov 2009 23:44:04 +0100 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: <4AF89B34.2040203@rubidium.dyndns.org> Eric Garner wrote: > So what are ships/planes supposed to if/when satellite navigation > becomes unreliable or unavailable ? But that doesn't happend, right? *ironic tone* With eLoran modernisation, there would be some chance of survival, but obviously focus is on stripping down the suit if it not can be motivated properly. Let's fact it, there will be a shut-down of all systems eventually. GPS is taking the approach of rolling in changes and cut signals _eventually_. But GPS is young compared to the Loran history. As for not being reliable or available, GPS works too well for people (except US and other nations military branches) to look serious at countermeasures like alternative signals or even hold-over properties or monitoring the existence and reliability of the signal. I think Loran-C receivers isn't as common in say telecom or other systems as they used to be. Cheers, Magnus From paulswedb at gmail.com Mon Nov 9 22:48:36 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 9 Nov 2009 17:48:36 -0500 Subject: [time-nuts] LORAN C shutdown In-Reply-To: <4AF89B34.2040203@rubidium.dyndns.org> References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> <4AF89B34.2040203@rubidium.dyndns.org> Message-ID: My impression is eLORAN is off the table. Since DHS is letting it go also. Sextant, compass, and a good chronometer. On Mon, Nov 9, 2009 at 5:44 PM, Magnus Danielson wrote: > Eric Garner wrote: > >> So what are ships/planes supposed to if/when satellite navigation >> becomes unreliable or unavailable ? >> > > But that doesn't happend, right? *ironic tone* > > With eLoran modernisation, there would be some chance of survival, but > obviously focus is on stripping down the suit if it not can be motivated > properly. > > Let's fact it, there will be a shut-down of all systems eventually. > > GPS is taking the approach of rolling in changes and cut signals > _eventually_. But GPS is young compared to the Loran history. > > As for not being reliable or available, GPS works too well for people > (except US and other nations military branches) to look serious at > countermeasures like alternative signals or even hold-over properties or > monitoring the existence and reliability of the signal. > > I think Loran-C receivers isn't as common in say telecom or other systems > as they used to be. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From alan.melia at btinternet.com Mon Nov 9 22:29:58 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 9 Nov 2009 22:29:58 -0000 Subject: [time-nuts] LORAN C shutdown References: Message-ID: <000501ca618f$682c45f0$0900a8c0@lark> Hi Paul, It wasnt my thread but the problem does occur that when you edit the subject line it doesnt change the "thread title" which is embedded in the original message I think. I rather expected the closure to happen. I was a bit surprised that it didnt close last year. My guess is the French will try to keep the W European chain running.As it happens it may scupper a little ionsopheric project I want to run using Loran-C. Thanks for the detail, someone else from the LF group saw something on a GPS site but their URL didnt work. Thanks and Best Wishes Alan G3NYK ----- Original Message ----- From: "paul swed" To: "Time-nuts" Sent: Monday, November 09, 2009 10:01 PM Subject: [time-nuts] LORAN C shutdown > Alan > Very sorry if I grabbed your thread. I thought I changed the header > > I finally found it in the senate votes this weekend. > The house and senate voted to shut it down and the president signed it. > (We will save .00002% of the budget) > The USCG and DHS said they had no need. > It was very hard to find, its not on the uscg or megapulse site > > Changed the header but maybe you can't start threads that way. > I sure would like to be very very wrong on this subject. > > Regards > Paul. > PS one day I will figure out why the reply says me > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From alan.melia at btinternet.com Mon Nov 9 22:41:19 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 9 Nov 2009 22:41:19 -0000 Subject: [time-nuts] LORAN C shutdown References: Message-ID: <000701ca618f$69eda500$0900a8c0@lark> Sell it into Europe Bob the French are bound to keep the W-European chain going, and VT comms has a 10 year contact to provide eLoran for Trinity house in the UK.....does this say something about their belief in Galilleo I wonder !! Alan G3NYK ----- Original Message ----- From: "Robert Darlington" To: "Discussion of precise time and frequency measurement" Sent: Monday, November 09, 2009 10:10 PM Subject: Re: [time-nuts] LORAN C shutdown > Anybody looking to buy an Austron 2000c ? Any takers? Any? > > > -Bob > > On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > > > Alan > > Very sorry if I grabbed your thread. I thought I changed the header > > > > I finally found it in the senate votes this weekend. > > The house and senate voted to shut it down and the president signed it. > > (We will save .00002% of the budget) > > The USCG and DHS said they had no need. > > It was very hard to find, its not on the uscg or megapulse site > > > > Changed the header but maybe you can't start threads that way. > > I sure would like to be very very wrong on this subject. > > > > Regards > > Paul. > > PS one day I will figure out why the reply says me > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From james.p.lux at jpl.nasa.gov Mon Nov 9 22:54:04 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Mon, 9 Nov 2009 14:54:04 -0800 Subject: [time-nuts] LORAN C shutdown In-Reply-To: Message-ID: On 11/9/09 2:43 PM, "paul swed" wrote: > I believe sextant > > On Mon, Nov 9, 2009 at 5:25 PM, Eric Garner wrote: > >> So what are ships/planes supposed to if/when satellite navigation >> becomes unreliable or unavailable ? >> >> >> On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: >>> The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. >>> --- What do they when the satellite stops? The same thing they do when Loran stops... celnav From alan.melia at btinternet.com Mon Nov 9 22:54:30 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 9 Nov 2009 22:54:30 -0000 Subject: [time-nuts] LORAN C shutdown References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: <000d01ca618f$9b558090$0900a8c0@lark> Dead Reckoning ?? ----- Original Message ----- From: "Eric Garner" To: "Discussion of precise time and frequency measurement" Sent: Monday, November 09, 2009 10:25 PM Subject: Re: [time-nuts] LORAN C shutdown So what are ships/planes supposed to if/when satellite navigation becomes unreliable or unavailable ? On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. > > See: > > http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf > > -John > > =============== > > > >> Anybody looking to buy an Austron 2000c ? Any takers? Any? >> >> >> -Bob >> >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: >> >>> Alan >>> Very sorry if I grabbed your thread. I thought I changed the header >>> >>> I finally found it in the senate votes this weekend. >>> The house and senate voted to shut it down and the president signed it. >>> (We will save .00002% of the budget) >>> The USCG and DHS said they had no need. >>> It was very hard to find, its not on the uscg or megapulse site >>> >>> Changed the header but maybe you can't start threads that way. >>> I sure would like to be very very wrong on this subject. >>> >>> Regards >>> Paul. >>> PS one day I will figure out why the reply says me >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- --Eric _________________________________________ Eric Garner _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From m0ycm at veenstras.com Mon Nov 9 22:54:55 2009 From: m0ycm at veenstras.com (Lester Veenstra) Date: Mon, 9 Nov 2009 22:54:55 -0000 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: Sextant and chronometer, of course! Lester B Veenstra M?YCM K1YCM lester at veenstras.com m0ycm at veenstras.com k1ycm at veenstras.com US Postal Address: PSC 45 Box 781 APO AE 09468 USA UK Postal Address: Dawn Cottage Norwood, Harrogate HG3 1SD, UK Telephones: Office: +44-(0)1423-846-385 Home: +44-(0)1943-880-963 Guam Cell: +1-671-788-5654 UK Cell: +44-(0)7716-298-224 US Cell: +1-240-425-7335 Jamaica: +1-876-352-7504 This e-mail and any documents attached hereto contain confidential or privileged information. The information is intended to be for use only by the individual or entity to whom they are addressed. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this e-mail or any documents attached hereto is prohibited. -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Eric Garner Sent: Monday, November 09, 2009 10:26 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] LORAN C shutdown So what are ships/planes supposed to if/when satellite navigation becomes unreliable or unavailable ? On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. > > See: > > http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf > > -John > > =============== > > > >> Anybody looking to buy an Austron 2000c ? ? Any takers? ?Any? >> >> >> -Bob >> >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: >> >>> Alan >>> ? ?Very sorry if I grabbed your thread. I thought I changed the header >>> >>> I finally found it in the senate votes this weekend. >>> The house and senate voted to shut it down and the president signed it. >>> (We will save .00002% of the budget) >>> The USCG and DHS said they had no need. >>> It was very hard to find, its not on the uscg or megapulse site >>> >>> Changed the header but maybe you can't start threads that way. >>> I sure would like to be very very wrong on this subject. >>> >>> Regards >>> Paul. >>> PS one day I will figure out why the reply says me >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- --Eric _________________________________________ Eric Garner _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From rdarlington at gmail.com Mon Nov 9 22:55:44 2009 From: rdarlington at gmail.com (Robert Darlington) Date: Mon, 9 Nov 2009 15:55:44 -0700 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: Triangulate with cell phone towers? ;) On Mon, Nov 9, 2009 at 3:54 PM, Lester Veenstra wrote: > Sextant and chronometer, of course! > > > Lester B Veenstra M?YCM K1YCM > lester at veenstras.com > m0ycm at veenstras.com > k1ycm at veenstras.com > > > US Postal Address: > PSC 45 Box 781 > APO AE 09468 USA > > UK Postal Address: > Dawn Cottage > Norwood, Harrogate > HG3 1SD, UK > > Telephones: > Office: +44-(0)1423-846-385 > Home: +44-(0)1943-880-963 > Guam Cell: +1-671-788-5654 > UK Cell: +44-(0)7716-298-224 > US Cell: +1-240-425-7335 > Jamaica: +1-876-352-7504 > > This e-mail and any documents attached hereto contain confidential or > privileged information. The information is intended to be for use only by > the individual or entity to whom they are addressed. If you are not the > intended recipient or the person responsible for delivering the e-mail to > the intended recipient, be aware that any disclosure, copying, distribution > or use of the contents of this e-mail or any documents attached hereto is > prohibited. > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Eric Garner > Sent: Monday, November 09, 2009 10:26 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] LORAN C shutdown > > So what are ships/planes supposed to if/when satellite navigation > becomes unreliable or unavailable ? > > > On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: > > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. > > > > See: > > > > > http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf > > > > -John > > > > =============== > > > > > > > >> Anybody looking to buy an Austron 2000c ? Any takers? Any? > >> > >> > >> -Bob > >> > >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > >> > >>> Alan > >>> Very sorry if I grabbed your thread. I thought I changed the header > >>> > >>> I finally found it in the senate votes this weekend. > >>> The house and senate voted to shut it down and the president signed it. > >>> (We will save .00002% of the budget) > >>> The USCG and DHS said they had no need. > >>> It was very hard to find, its not on the uscg or megapulse site > >>> > >>> Changed the header but maybe you can't start threads that way. > >>> I sure would like to be very very wrong on this subject. > >>> > >>> Regards > >>> Paul. > >>> PS one day I will figure out why the reply says me > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts at febo.com > >>> To unsubscribe, go to > >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > --Eric > _________________________________________ > Eric Garner > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From phk at phk.freebsd.dk Mon Nov 9 22:56:03 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 09 Nov 2009 22:56:03 +0000 Subject: [time-nuts] LORAN C shutdown In-Reply-To: Your message of "Mon, 09 Nov 2009 15:10:22 MST." Message-ID: <2697.1257807363@critter.freebsd.dk> In message , Robert Darlington writes: >Anybody looking to buy an Austron 2000c ? Any takers? Any? You should complain, I built one from scratch: http://phk.freebsd.dk/AducLoran/AducLoran-0.3.pdf :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From pete at petelancashire.com Mon Nov 9 23:14:43 2009 From: pete at petelancashire.com (Pete Lancashire) Date: Mon, 9 Nov 2009 15:14:43 -0800 Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: Message-ID: That old Carousel IV buried in the back of my garage my someday have a use again -pete > Anybody looking to buy an Austron 2000c ? Any takers? Any? > > > -Bob > > On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > >> Alan >> Very sorry if I grabbed your thread. I thought I changed the header >> >> I finally found it in the senate votes this weekend. >> The house and senate voted to shut it down and the president signed it. >> (We will save .00002% of the budget) >> The USCG and DHS said they had no need. >> It was very hard to find, its not on the uscg or megapulse site >> >> Changed the header but maybe you can't start threads that way. >> I sure would like to be very very wrong on this subject. >> >> Regards >> Paul. >> PS one day I will figure out why the reply says me >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jfor at quik.com Mon Nov 9 23:01:00 2009 From: jfor at quik.com (J. Forster) Date: Mon, 9 Nov 2009 15:01:00 -0800 (PST) Subject: [time-nuts] LORAN C shutdown In-Reply-To: References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: <2428.12.6.201.237.1257807660.squirrel@popacctsnew.quik.com> Very few cell towers in mid ocean and GPS signals are blocked by trees. Congress are IDIOTS. -John ================ > Triangulate with cell phone towers? ;) > > On Mon, Nov 9, 2009 at 3:54 PM, Lester Veenstra > wrote: > >> Sextant and chronometer, of course! >> >> >> Lester B Veenstra M?YCM K1YCM >> lester at veenstras.com >> m0ycm at veenstras.com >> k1ycm at veenstras.com >> >> >> US Postal Address: >> PSC 45 Box 781 >> APO AE 09468 USA >> >> > UK Postal Address: >> Dawn Cottage >> Norwood, Harrogate >> HG3 1SD, UK >> >> Telephones: >> Office: +44-(0)1423-846-385 >> Home: +44-(0)1943-880-963 >> Guam Cell: +1-671-788-5654 >> UK Cell: +44-(0)7716-298-224 >> US Cell: +1-240-425-7335 >> Jamaica: +1-876-352-7504 >> >> This e-mail and any documents attached hereto contain confidential or >> privileged information. The information is intended to be for use only >> by >> the individual or entity to whom they are addressed. If you are not the >> intended recipient or the person responsible for delivering the e-mail >> to >> the intended recipient, be aware that any disclosure, copying, >> distribution >> or use of the contents of this e-mail or any documents attached hereto >> is >> prohibited. >> >> -----Original Message----- >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On >> Behalf Of Eric Garner >> Sent: Monday, November 09, 2009 10:26 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] LORAN C shutdown >> >> So what are ships/planes supposed to if/when satellite navigation >> becomes unreliable or unavailable ? >> >> >> On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: >> > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, >> 2010. >> > >> > See: >> > >> > >> http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf >> > >> > -John >> > >> > =============== >> > >> > >> > >> >> Anybody looking to buy an Austron 2000c ? Any takers? Any? >> >> >> >> >> >> -Bob >> >> >> >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed >> wrote: >> >> >> >>> Alan >> >>> Very sorry if I grabbed your thread. I thought I changed the >> header >> >>> >> >>> I finally found it in the senate votes this weekend. >> >>> The house and senate voted to shut it down and the president signed >> it. >> >>> (We will save .00002% of the budget) >> >>> The USCG and DHS said they had no need. >> >>> It was very hard to find, its not on the uscg or megapulse site >> >>> >> >>> Changed the header but maybe you can't start threads that way. >> >>> I sure would like to be very very wrong on this subject. >> >>> >> >>> Regards >> >>> Paul. >> >>> PS one day I will figure out why the reply says me >> >>> _______________________________________________ >> >>> time-nuts mailing list -- time-nuts at febo.com >> >>> To unsubscribe, go to >> >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >>> and follow the instructions there. >> >>> >> >> _______________________________________________ >> >> time-nuts mailing list -- time-nuts at febo.com >> >> To unsubscribe, go to >> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> and follow the instructions there. >> >> >> >> >> > >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- time-nuts at febo.com >> > To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> > >> >> >> >> -- >> --Eric >> _________________________________________ >> Eric Garner >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From phk at phk.freebsd.dk Mon Nov 9 23:06:26 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 09 Nov 2009 23:06:26 +0000 Subject: [time-nuts] LORAN C shutdown In-Reply-To: Your message of "Mon, 09 Nov 2009 14:54:04 PST." Message-ID: <2893.1257807986@critter.freebsd.dk> Don't overlook that laser/fiber "ring-gyros" will drop in price the patents expire and the predatory pricing ends: http://www.es.northropgrumman.com/solutions/mk39/assets/mk39.pdf As much as I have enjoyed playing with Loran-C, I would far rather have a shoebox-sized, totally autonomous dead-reckoning backup, with no lightning-prone antenna, than a Loran-C receiver. Doesn't help us timing guys, but we have Cesiums if we are really serious. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From alan.melia at btinternet.com Mon Nov 9 23:23:55 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 9 Nov 2009 23:23:55 -0000 Subject: [time-nuts] LORAN C shutdown References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> Message-ID: <003a01ca6193$be25b730$0900a8c0@lark> There is a system in the UK that already does that and used digital TV as well I believe. The accurate nav is only really needed in coastal water and the phones cover most of those. Ain't many trees in the middle of the ocean either John, but we are working on it as a disguse for deep sea oil drilling platforms :-)) Alan G3NYK ----- Original Message ----- From: "Robert Darlington" To: ; "Discussion of precise time and frequency measurement" Sent: Monday, November 09, 2009 10:55 PM Subject: Re: [time-nuts] LORAN C shutdown Triangulate with cell phone towers? ;) On Mon, Nov 9, 2009 at 3:54 PM, Lester Veenstra wrote: > Sextant and chronometer, of course! > > > Lester B Veenstra M?YCM K1YCM > lester at veenstras.com > m0ycm at veenstras.com > k1ycm at veenstras.com > > > US Postal Address: > PSC 45 Box 781 > APO AE 09468 USA > > UK Postal Address: > Dawn Cottage > Norwood, Harrogate > HG3 1SD, UK > > Telephones: > Office: +44-(0)1423-846-385 > Home: +44-(0)1943-880-963 > Guam Cell: +1-671-788-5654 > UK Cell: +44-(0)7716-298-224 > US Cell: +1-240-425-7335 > Jamaica: +1-876-352-7504 > > This e-mail and any documents attached hereto contain confidential or > privileged information. The information is intended to be for use only by > the individual or entity to whom they are addressed. If you are not the > intended recipient or the person responsible for delivering the e-mail to > the intended recipient, be aware that any disclosure, copying, distribution > or use of the contents of this e-mail or any documents attached hereto is > prohibited. > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Eric Garner > Sent: Monday, November 09, 2009 10:26 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] LORAN C shutdown > > So what are ships/planes supposed to if/when satellite navigation > becomes unreliable or unavailable ? > > > On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: > > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. > > > > See: > > > > > http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf > > > > -John > > > > =============== > > > > > > > >> Anybody looking to buy an Austron 2000c ? Any takers? Any? > >> > >> > >> -Bob > >> > >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: > >> > >>> Alan > >>> Very sorry if I grabbed your thread. I thought I changed the header > >>> > >>> I finally found it in the senate votes this weekend. > >>> The house and senate voted to shut it down and the president signed it. > >>> (We will save .00002% of the budget) > >>> The USCG and DHS said they had no need. > >>> It was very hard to find, its not on the uscg or megapulse site > >>> > >>> Changed the header but maybe you can't start threads that way. > >>> I sure would like to be very very wrong on this subject. > >>> > >>> Regards > >>> Paul. > >>> PS one day I will figure out why the reply says me > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts at febo.com > >>> To unsubscribe, go to > >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >>> and follow the instructions there. > >>> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts at febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > --Eric > _________________________________________ > Eric Garner > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From jfor at quik.com Mon Nov 9 23:29:23 2009 From: jfor at quik.com (J. Forster) Date: Mon, 9 Nov 2009 15:29:23 -0800 (PST) Subject: [time-nuts] LORAN C shutdown In-Reply-To: <003a01ca6193$be25b730$0900a8c0@lark> References: <2399.12.6.201.237.1257804865.squirrel@popacctsnew.quik.com> <003a01ca6193$be25b730$0900a8c0@lark> Message-ID: <2471.12.6.201.237.1257809363.squirrel@popacctsnew.quik.com> The tree reference is for nav in forest or jungle canopy areas. A very few trees will largely kill GPS. LORAN does not care. I have that exact problem. -John ============ > There is a system in the UK that already does that and used digital TV as > well I believe. The accurate nav is only really needed in coastal water > and > the phones cover most of those. Ain't many trees in the middle of the > ocean > either John, but we are working on it as a disguse for deep sea oil > drilling > platforms :-)) > > Alan G3NYK From rputz at bnin.net Mon Nov 9 23:53:59 2009 From: rputz at bnin.net (Rich and Marcia Putz) Date: Mon, 9 Nov 2009 18:53:59 -0500 Subject: [time-nuts] Loran C shut down Message-ID: <001001ca6197$e9bdb380$9d83e262@newiw112a268qp> Hi all; I guess this is change we can believe in! Rich From robert8rpi at yahoo.co.uk Tue Nov 10 07:35:03 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Tue, 10 Nov 2009 07:35:03 +0000 (GMT) Subject: [time-nuts] LORAN C shutdown In-Reply-To: Message-ID: <583195.68097.qm@web27108.mail.ukl.yahoo.com> Unfortunatly very few commercial aircraft carry Loran C equipment. The large ones?would fall back on inertial navigation. ? Robert G8RPI. --- On Mon, 9/11/09, Eric Garner wrote: From: Eric Garner Subject: Re: [time-nuts] LORAN C shutdown To: "Discussion of precise time and frequency measurement" Date: Monday, 9 November, 2009, 22:25 So what are ships/planes supposed to if/when satellite navigation becomes unreliable or unavailable ? On Mon, Nov 9, 2009 at 2:14 PM, J. Forster wrote: > The Congress is UTTERLY CLUELESS. It's supposed to shut down Jan 4, 2010. > > See: > > http://appropriations.house.gov/pdf/Homeland_Security_FY10_Conference.pdf > > -John > > =============== > > > >> Anybody looking to buy an Austron 2000c ? ? Any takers? ?Any? >> >> >> -Bob >> >> On Mon, Nov 9, 2009 at 3:01 PM, paul swed wrote: >> >>> Alan >>> ? ?Very sorry if I grabbed your thread. I thought I changed the header >>> >>> I finally found it in the senate votes this weekend. >>> The house and senate voted to shut it down and the president signed it. >>> (We will save .00002% of the budget) >>> The USCG and DHS said they had no need. >>> It was very hard to find, its not on the uscg or megapulse site >>> >>> Changed the header but maybe you can't start threads that way. >>> I sure would like to be very very wrong on this subject. >>> >>> Regards >>> Paul. >>> PS one day I will figure out why the reply says me >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- --Eric _________________________________________ Eric Garner _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From robert8rpi at yahoo.co.uk Tue Nov 10 07:59:31 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Tue, 10 Nov 2009 07:59:31 +0000 (GMT) Subject: [time-nuts] LORAN C shutdown In-Reply-To: <2893.1257807986@critter.freebsd.dk> Message-ID: <735418.18610.qm@web27103.mail.ukl.yahoo.com> Correct, They are already at a price and size where they are making it onto light aircraft. An IN platform is life cycle cost competitive with a mechanical vertical/directional gyro pair and adding navigation is "just" (cheap apart from the RTCA DO-178 assurance) software.? Echos of the end of Omega. The company I was working for had just added GPS modules to their Tracor Omega/VLF navigation systems. Unfortunately as the GPS was secondary to the Omega, they were not able to use them when the Omega was turn off. ? Robert G8RPI (MRAeS, day job avionics design engineer) --- On Mon, 9/11/09, Poul-Henning Kamp wrote: From: Poul-Henning Kamp Subject: Re: [time-nuts] LORAN C shutdown To: "Discussion of precise time and frequency measurement" Date: Monday, 9 November, 2009, 23:06 Don't overlook that laser/fiber "ring-gyros" will drop in price the patents expire and the predatory pricing ends: ??? http://www.es.northropgrumman.com/solutions/mk39/assets/mk39.pdf As much as I have enjoyed playing with Loran-C, I would far rather have a shoebox-sized, totally autonomous dead-reckoning backup, with no lightning-prone antenna, than a Loran-C receiver. Doesn't help us timing guys, but we have Cesiums if we are really serious. -- Poul-Henning Kamp? ? ???| UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG? ? ? ???| TCP/IP since RFC 956 FreeBSD committer? ? ???| BSD since 4.3-tahoe? ? Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From GandalfG8 at aol.com Tue Nov 10 08:39:39 2009 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Tue, 10 Nov 2009 03:39:39 EST Subject: [time-nuts] LORAN C shutdown Message-ID: In a message dated 09/11/2009 23:24:27 GMT Standard Time, alan.melia at btinternet.com writes: There is a system in the UK that already does that and used digital TV as well I believe. The accurate nav is only really needed in coastal water and the phones cover most of those. Ain't many trees in the middle of the ocean either John, but we are working on it as a disguse for deep sea oil drilling platforms :-)) -------------------- Sounds like a job for......Decca Navigator Man :-) regards Nigel GM8PZR From jgray at zianet.com Tue Nov 10 16:46:49 2009 From: jgray at zianet.com (Joseph Gray) Date: Tue, 10 Nov 2009 09:46:49 -0700 Subject: [time-nuts] Oscillator for service monitor Message-ID: A friend of mine is looking for a suitable replacement for the timebase in his Motorola S1327A service monitor. Here is the description he sent me for the existing oscillator. 1 Mhz Oscillator. Made by: Monitor PO of Pasadena, CA. Mfg Date 05/73 Heater is 115VAC. Osc power is 30VDC (+15 and -15). Can is 1.5 inches square. 3.75 inches long. Has an 8 pin Octal Socket on one end. Adjusting cap on other end. Can anyone suggest a suitable substitute? According to my friend, replacement units are no longer available and other, used units are usually also defective. From tvb at LeapSecond.com Tue Nov 10 19:28:53 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Tue, 10 Nov 2009 11:28:53 -0800 Subject: [time-nuts] Oncore glitch? Message-ID: I've been asked if anyone noticed an iLotus / Motorola Oncore or M12 GPS receiver glitch a week ago (Wednesday 5 Nov at about 1900Z)? (no need to reply if your GPS receivers kept ticking; I'm just looking here for reports of any signal or tracking anomaly at the time in question) Thanks, /tvb From bg at lysator.liu.se Tue Nov 10 19:29:33 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Tue, 10 Nov 2009 20:29:33 +0100 (CET) Subject: [time-nuts] LORAN C shutdown In-Reply-To: <2893.1257807986@critter.freebsd.dk> References: <2893.1257807986@critter.freebsd.dk> Message-ID: <1422.41.130.184.218.1257881373.squirrel@webmail.lysator.liu.se> On the other hand... With GPS-aiding its argued that high performance INS-systems are not needed. The same performance will be reached with a low cost GPS and a mid to low performance inertial system. So I doubt we will have low cost high performance intertial sensors anytime soon. -- Bj?rn > Don't overlook that laser/fiber "ring-gyros" will drop in price the > patents expire and the predatory pricing ends: > > http://www.es.northropgrumman.com/solutions/mk39/assets/mk39.pdf > > As much as I have enjoyed playing with Loran-C, I would far rather > have a shoebox-sized, totally autonomous dead-reckoning backup, with > no lightning-prone antenna, than a Loran-C receiver. > > Doesn't help us timing guys, but we have Cesiums if we are really > serious. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk at FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by > incompetence. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From garren.davis at qlogic.com Tue Nov 10 19:44:23 2009 From: garren.davis at qlogic.com (Garren Davis) Date: Tue, 10 Nov 2009 11:44:23 -0800 Subject: [time-nuts] Oncore glitch? In-Reply-To: References: Message-ID: <97F2C39DA7F34443BD6C8E40EA8102F9843D8EACE6@AVEXMB1.qlogic.org> I don't remember what day it was but last week I looked at my TAC32 program and noticed it had lost lock. It showed no satellites tracked. I restarted TAC32 and all was well. I use a Motorola Oncore and thought it might be something to do with daylight saving time changing. Garren -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Tom Van Baak Sent: Tuesday, November 10, 2009 11:29 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Oncore glitch? I've been asked if anyone noticed an iLotus / Motorola Oncore or M12 GPS receiver glitch a week ago (Wednesday 5 Nov at about 1900Z)? (no need to reply if your GPS receivers kept ticking; I'm just looking here for reports of any signal or tracking anomaly at the time in question) Thanks, /tvb _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From smace at intt.net Tue Nov 10 19:54:20 2009 From: smace at intt.net (Scott Mace) Date: Tue, 10 Nov 2009 13:54:20 -0600 Subject: [time-nuts] Oncore glitch? In-Reply-To: References: Message-ID: <4AF9C4EC.9000107@intt.net> I noticed a glitch at about 0100Z on 11/5/09 with a Fury. Unit has been tracking within +-10ns for many months, and then suddenly jumped to -40ns or so and recovered. Not sure if it lost lock or was in holdover. I wasn't monitoring it with GPScon prior to the event (I had rebooted the vm that it was running on and forgot to restart GPScon). By happenstance I restart it and noticed the large TI error. There was also some noise on outages at outages.org about GPS errors around the same time. Scott On 11/10/2009 1:28 PM, Tom Van Baak wrote: > I've been asked if anyone noticed an iLotus / Motorola Oncore > or M12 GPS receiver glitch a week ago (Wednesday 5 Nov at > about 1900Z)? > > (no need to reply if your GPS receivers kept ticking; I'm just > looking here for reports of any signal or tracking anomaly at > the time in question) > > Thanks, > /tvb > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From robert8rpi at yahoo.co.uk Tue Nov 10 20:58:57 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Tue, 10 Nov 2009 20:58:57 +0000 (GMT) Subject: [time-nuts] LORAN C shutdown In-Reply-To: <1422.41.130.184.218.1257881373.squirrel@webmail.lysator.liu.se> Message-ID: <502956.17340.qm@web27102.mail.ukl.yahoo.com> Hi Bjorn, This depends on what you call high performance. The normal definition of?"high performance" in relation to IN is low drift with time. Even "cheap" fibre optic gyro based IN platforms?can perform as well as the early?airline standard mecanical?units.?GPS does not provide attitude or heading information (I'm ignoring specialist multi antenna differential set ups, these are not normal or mature systems). This information is needed in real time to fly the aircraft in IMC (low visibility) or on autopilot. Either attitude and directional gyros or an IN platform are still needed and IN is becoming the norm. There are also MEMS units that are making inroads in the light aviation market, especially in the USA.?GPS (or to be more accurate GNSS) is only part of the system, all be it a very important one. ? ? Robert G8RPI. --- On Tue, 10/11/09, bg at lysator.liu.se wrote: From: bg at lysator.liu.se Subject: Re: [time-nuts] LORAN C shutdown To: "Discussion of precise time and frequency measurement" Date: Tuesday, 10 November, 2009, 19:29 On the other hand... With GPS-aiding its argued that high performance INS-systems are not needed. The same performance will be reached with a low cost GPS and a mid to low performance inertial system. So I doubt we will have low cost high performance intertial sensors anytime soon. -- ???Bj?rn > Don't overlook that laser/fiber "ring-gyros" will drop in price the > patents expire and the predatory pricing ends: > > ??? http://www.es.northropgrumman.com/solutions/mk39/assets/mk39.pdf > > As much as I have enjoyed playing with Loran-C, I would far rather > have a shoebox-sized, totally autonomous dead-reckoning backup, with > no lightning-prone antenna, than a Loran-C receiver. > > Doesn't help us timing guys, but we have Cesiums if we are really > serious. > > -- > Poul-Henning Kamp? ? ???| UNIX since Zilog Zeus 3.20 > phk at FreeBSD.ORG? ? ? ???| TCP/IP since RFC 956 > FreeBSD committer? ? ???| BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by > incompetence. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From joegeller at roadrunner.com Tue Nov 10 21:07:03 2009 From: joegeller at roadrunner.com (Joe Geller) Date: Tue, 10 Nov 2009 16:07:03 -0500 Subject: [time-nuts] 5370B PROM Message-ID: <200911101673.067574@nectarine> My 5370B PROM turns out to be fine (there was some operator error) I picked up a DATA I/O 201 programmer and some NOS windowed MOT MCM68764C to have some backups (this was probably overkill, since I have never actually seen a failed hp counter from ROM failure) A newly burned MCM68764C appears to work perfectly. The programmer reports SUMCHECK 7387 for U3, 5370B Ser. No. 2438A 01154 The programmer can report in the following formats: INTEL INTELLEC 8, INTEL MCS-86 HEX, MOTOROLA EXCERCIS, MOTOROLA EXORMAX, and TEKTRONIX HEX I can read these formats to a text file using a Windows terminal emulator to save them to a file, however, I do not know how to make the ?ROM Image?. I was hoping to be able to say something about the ROM version, but I do not know how to compare the files I get to the available 5370B ROM image? The DATA I/O 201 does not appear to directly save the binary file. I can supply a few replacement 5370B ROMs at cost plus shipping if anyone needs one. Regards, Joe From bg at lysator.liu.se Tue Nov 10 21:53:37 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Tue, 10 Nov 2009 22:53:37 +0100 (CET) Subject: [time-nuts] LORAN C shutdown In-Reply-To: <502956.17340.qm@web27102.mail.ukl.yahoo.com> References: <502956.17340.qm@web27102.mail.ukl.yahoo.com> Message-ID: <2455.41.130.184.218.1257890017.squirrel@webmail.lysator.liu.se> Hi Robert, High performance - for me - is 'navigation grade' wrt intertial systems. Your terminology is somewhat strange to me. 'IN' is that short for INertial or Inertial Navigation? There are (used to be) two basic types of intertial navigation systems; platform systems, where a number of gimbals with help from the gyros keep the central accelerometer platform at a constant orientation. The other type is strapdown systems, where gyros and accelerometers are mounted fixed within the INS box. High performance mechanical rotating gyros are associated with platform systems. Ring laser gyros and fiber optic gyros are typically strapdown, which completely dominate modern navigation. I doubt that your "cheap" FOG IN platform really is a platform system. I also very much doubt that these FOG systems perform as well as older mechanical platform inertial navigation systems! If you compare with vertical gyro-types, those are for aircraft control, not for navigation. Any IMU integrated with GPS/GNSS provides complete attitude information on moving platforms. There are certified pure GNSS heading sensors on the marine and other markets. -- Bj?rn > Hi Bjorn, > This depends on what you call high performance. The normal definition > of?"high performance" in relation to IN is low drift with time. Even > "cheap" fibre optic gyro based IN platforms?can perform as well as the > early?airline standard mecanical?units.?GPS does not provide attitude or > heading information (I'm ignoring specialist multi antenna differential > set ups, these are not normal or mature systems). This information is > needed in real time to fly the aircraft in IMC (low visibility) or on > autopilot. Either attitude and directional gyros or an IN platform are > still needed and IN is becoming the norm. There are also MEMS units that > are making inroads in the light aviation market, especially in the > USA.?GPS (or to be more accurate GNSS) is only part of the system, all be > it a very important one. > ? > ? > Robert G8RPI. > > > --- On Tue, 10/11/09, bg at lysator.liu.se wrote: > > > From: bg at lysator.liu.se > Subject: Re: [time-nuts] LORAN C shutdown > To: "Discussion of precise time and frequency measurement" > > Date: Tuesday, 10 November, 2009, 19:29 > > > On the other hand... With GPS-aiding its argued that high performance > INS-systems are not needed. The same performance will be reached with a > low cost GPS and a mid to low performance inertial system. So I doubt we > will have low cost high performance intertial sensors anytime soon. > > -- > > ???Bj?rn > >> Don't overlook that laser/fiber "ring-gyros" will drop in price the >> patents expire and the predatory pricing ends: >> >> ??? http://www.es.northropgrumman.com/solutions/mk39/assets/mk39.pdf >> >> As much as I have enjoyed playing with Loran-C, I would far rather >> have a shoebox-sized, totally autonomous dead-reckoning backup, with >> no lightning-prone antenna, than a Loran-C receiver. >> >> Doesn't help us timing guys, but we have Cesiums if we are really >> serious. >> >> -- >> Poul-Henning Kamp? ? ???| UNIX since Zilog Zeus 3.20 >> phk at FreeBSD.ORG? ? ? ???| TCP/IP since RFC 956 >> FreeBSD committer? ? ???| BSD since 4.3-tahoe >> Never attribute to malice what can adequately be explained by >> incompetence. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From phk at phk.freebsd.dk Tue Nov 10 22:00:35 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Tue, 10 Nov 2009 22:00:35 +0000 Subject: [time-nuts] LORAN C shutdown In-Reply-To: Your message of "Tue, 10 Nov 2009 22:53:37 +0100." <2455.41.130.184.218.1257890017.squirrel@webmail.lysator.liu.se> Message-ID: <21494.1257890435@critter.freebsd.dk> In message <2455.41.130.184.218.1257890017.squirrel at webmail.lysator.liu.se>, bg @lysator.liu.se writes: >High performance mechanical rotating gyros are associated with platform >systems. Ring laser gyros and fiber optic gyros are typically strapdown, >which completely dominate modern navigation. Actually, they are usually strapped down to a deliberately moving platform to avoid mode-lock-in at the mirrors, which produces a "sticky" or "discrete steps" effect at slow rates of rotation. But that is a minor detail. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From john at pcsupportsolutions.com Tue Nov 10 22:01:40 2009 From: john at pcsupportsolutions.com (John Allen) Date: Tue, 10 Nov 2009 17:01:40 -0500 Subject: [time-nuts] 5370B PROM In-Reply-To: <200911101673.067574@nectarine> References: <200911101673.067574@nectarine> Message-ID: <75A7DDDF-86D3-4B4A-9F10-C9B636CC57F7@pcsupportsolutions.com> Hi Joe - Thanks for the good info. I would like a back rom. Thanks, John K1AE Sent from my iPhone On Nov 10, 2009, at 4:07 PM, Joe Geller wrote: > My 5370B PROM turns out to be fine (there was some operator error) > I picked up a DATA I/O 201 programmer and some NOS windowed > MOT MCM68764C to have some backups (this was probably overkill, since > I have never actually seen a failed hp counter from ROM failure) > > A newly burned MCM68764C appears to work perfectly. > The programmer reports SUMCHECK 7387 for U3, 5370B Ser. No. 2438A > 01154 > > The programmer can report in the following formats: > INTEL INTELLEC 8, INTEL MCS-86 HEX, > MOTOROLA EXCERCIS, MOTOROLA EXORMAX, and > TEKTRONIX HEX > > I can read these formats to a text file using a Windows terminal > emulator to save them to a file, > however, I do not know how to make the ?ROM Image?. I was hoping > to be able to say something > about the ROM version, but I do not know how to compare the files I > get to > the available 5370B ROM image? The DATA I/O 201 does not appear to > directly save the binary file. > > I can supply a few replacement 5370B ROMs at cost plus shipping if > anyone needs one. > > Regards, > Joe > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From kyrrin at bluefeathertech.com Tue Nov 10 22:29:16 2009 From: kyrrin at bluefeathertech.com (Bruce Lane) Date: Tue, 10 Nov 2009 14:29:16 -0800 Subject: [time-nuts] 5370B PROM In-Reply-To: <200911101673.067574@nectarine> References: <200911101673.067574@nectarine> Message-ID: <200911101429160406.0134B367@192.168.42.129> Good day, *********** REPLY SEPARATOR *********** On 10-Nov-09 at 16:07 Joe Geller wrote: >I can read these formats to a text file using a Windows terminal emulator >to save them to a file, >however, I do not know how to make the ?ROM Image?. Technically, a ROM image is made by creating an Absolute Binary (Data I/O #16) format file of the device being read. However, formats such as you describe were, if I recall correctly, compatible with being read from a text file as long as the programmer being used to make a new device supports the format in question. I have other Data I/O programmers here which are quite capable of producing a binary image file. If you would like to send a chip to me for comparison against the source file you're curious about, I should be able to deal with it and return said chip when finished. Happy tweaking. From mikes at flatsurface.com Tue Nov 10 23:01:44 2009 From: mikes at flatsurface.com (Mike S) Date: Tue, 10 Nov 2009 18:01:44 -0500 Subject: [time-nuts] 5370B PROM In-Reply-To: <200911101429160406.0134B367@192.168.42.129> References: <200911101673.067574@nectarine> <200911101429160406.0134B367@192.168.42.129> Message-ID: <20091110230214.2E41A1165C1@hamburg.alientech.net> At 05:29 PM 11/10/2009, Bruce Lane wrote... >you describe were, if I recall correctly, compatible with being read >from >a text file as long as the programmer being used to make a new device >supports the format in question. The common Intel Hex and Motorola S-Record formats have the advantage of being able to incorporate checksums to assure some level of integrity, which is why they're used to distribute PROM files. Both enjoy almost universal support. A binary file has no such protection. The srec utility ( http://srecord.sourceforge.net/ ) can translate between many common formats, including binary. The image Joe went out of his way to obtain turns out to be the same as the 5370B image discussed earlier on the list (and which I documented at http://www.flatsurface.com/5370A/index.html ), but there's another 4 1/2 years of 5370B date codes beyond, so there may yet be a newer version. From magnus at rubidium.dyndns.org Wed Nov 11 00:01:48 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Wed, 11 Nov 2009 01:01:48 +0100 Subject: [time-nuts] LORAN C shutdown In-Reply-To: <21494.1257890435@critter.freebsd.dk> References: <21494.1257890435@critter.freebsd.dk> Message-ID: <4AF9FEEC.7090801@rubidium.dyndns.org> Poul-Henning Kamp wrote: > In message <2455.41.130.184.218.1257890017.squirrel at webmail.lysator.liu.se>, bg > @lysator.liu.se writes: > >> High performance mechanical rotating gyros are associated with platform >> systems. Ring laser gyros and fiber optic gyros are typically strapdown, >> which completely dominate modern navigation. > > Actually, they are usually strapped down to a deliberately moving > platform to avoid mode-lock-in at the mirrors, which produces a > "sticky" or "discrete steps" effect at slow rates of rotation. > > But that is a minor detail. While such laser gyros need to vibrate their mirrors to avoid the locking (having heard the audioble noise out of Bj?rns basement lab) they remain part of the strap-down system. A little bit of vibration is nothing to rotating objects. There is also gyros having no vibration at all, but uses a roll of fiber instead. Cheers, Magnus From va2hdd at aei.ca Wed Nov 11 01:36:32 2009 From: va2hdd at aei.ca (Claude Houde) Date: Tue, 10 Nov 2009 20:36:32 -0500 Subject: [time-nuts] Loran C shutdown Message-ID: <4AFA1520.5080609@aei.ca> Hello ! Before you throw away your Loran Receivers, have you checked what will happen with the Canadian Transmitter Chains ? Would it be possible with better antennas to receive signals from other countries ? Would be interested in hearing your input on these ideas ! Thanks ! Claude From jfor at quik.com Wed Nov 11 01:38:25 2009 From: jfor at quik.com (J. Forster) Date: Tue, 10 Nov 2009 17:38:25 -0800 (PST) Subject: [time-nuts] Loran C shutdown In-Reply-To: <4AFA1520.5080609@aei.ca> References: <4AFA1520.5080609@aei.ca> Message-ID: <2074.12.6.201.54.1257903505.squirrel@popacctsnew.quik.com> Also, somebody mentioned French chains. Any info on those would be appreciated. They might worl, especially on the east coast. -John ============== > Hello ! > > Before you throw away your Loran Receivers, have you checked what will > happen with the Canadian Transmitter Chains ? > > Would it be possible with better antennas to receive signals from other > countries ? > > Would be interested in hearing your input on these ideas ! > > Thanks ! > > Claude From SAIDJACK at aol.com Wed Nov 11 02:15:43 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Tue, 10 Nov 2009 21:15:43 EST Subject: [time-nuts] Oncore glitch? Message-ID: Hi Tom, I happen to have captured data from our FireFly-IIA GPSDO with uBlox gps, there was an anomaly around 18:55 Zulu on Nov 5th, please see the attached raw data, and screen capture. Hope this helps, bye, Said In a message dated 11/10/2009 11:29:59 Pacific Standard Time, tvb at LeapSecond.com writes: I've been asked if anyone noticed an iLotus / Motorola Oncore or M12 GPS receiver glitch a week ago (Wednesday 5 Nov at about 1900Z)? (no need to reply if your GPS receivers kept ticking; I'm just looking here for reports of any signal or tracking anomaly at the time in question) Thanks, /tvb -------------- next part -------------- A non-text attachment was scrubbed... Name: export.png Type: application/octet-stream Size: 25713 bytes Desc: not available URL: -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: Nov5th_Anomaly.txt URL: From jpeters at nvidia.com Wed Nov 11 03:23:21 2009 From: jpeters at nvidia.com (Jerome Peters) Date: Tue, 10 Nov 2009 19:23:21 -0800 Subject: [time-nuts] Loran C shutdown Message-ID: Is Loran C used with GPS to help make land surveying more accurate? I thought I read something about using both systems together. ----------------------------------------------------------------------------------- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. ----------------------------------------------------------------------------------- From paulswedb at gmail.com Wed Nov 11 03:44:27 2009 From: paulswedb at gmail.com (paul swed) Date: Tue, 10 Nov 2009 22:44:27 -0500 Subject: [time-nuts] Loran C shutdown In-Reply-To: <4AFA1520.5080609@aei.ca> References: <4AFA1520.5080609@aei.ca> Message-ID: Well that's what I am thinking about also. Earlier in this thread there was a mention of Europe. This would be a sky wave only signal as I recall from the navy. So I have g3plx LORAN software and will look to see what I might get here on the east coast. Suspect the Canadian chains will go very quickly since part of them uses the US chain. Or simpler then the g3plx software, just plugging in the GRI for the European chains. Have 3 austron receivers, the 2000c, 2100, and 2100f. On Tue, Nov 10, 2009 at 8:36 PM, Claude Houde wrote: > Hello ! > > Before you throw away your Loran Receivers, have you checked what will > happen with the Canadian Transmitter Chains ? > > Would it be possible with better antennas to receive signals from other > countries ? > > Would be interested in hearing your input on these ideas ! > > Thanks ! > > Claude > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From asmagal at fc.up.pt Wed Nov 11 03:57:41 2009 From: asmagal at fc.up.pt (asmagal at fc.up.pt) Date: Wed, 11 Nov 2009 04:57:41 +0100 Subject: [time-nuts] Loran C shutdown In-Reply-To: References: <4AFA1520.5080609@aei.ca> Message-ID: <20091111045741.0x71fvkdckskwg0g@webmail.fc.up.pt> The problem with the some European chains is that they have four-digit GRPs . Therefore, the standard 2000C and maybe others are useless. Regards, Antonio CT1TE Quoting paul swed : > Well that's what I am thinking about also. > Earlier in this thread there was a mention of Europe. > This would be a sky wave only signal as I recall from the navy. > So I have g3plx LORAN software and will look to see what I might get here on > the east coast. > Suspect the Canadian chains will go very quickly since part of them uses the > US chain. > Or simpler then the g3plx software, just plugging in the GRI for the > European chains. > Have 3 austron receivers, the 2000c, 2100, and 2100f. > > > On Tue, Nov 10, 2009 at 8:36 PM, Claude Houde wrote: > >> Hello ! >> >> Before you throw away your Loran Receivers, have you checked what will >> happen with the Canadian Transmitter Chains ? >> >> Would it be possible with better antennas to receive signals from other >> countries ? >> >> Would be interested in hearing your input on these ideas ! >> >> Thanks ! >> >> Claude >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ------------------------------------------------------------------------- A FCUP utiliza o sistema open source de webmail Horde/IMP (www.horde.org) Visite: http://www.fc.up.pt/ http://info.fc.up.pt/ From bg at lysator.liu.se Wed Nov 11 05:30:22 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Wed, 11 Nov 2009 06:30:22 +0100 (CET) Subject: [time-nuts] LORAN C shutdown In-Reply-To: <21494.1257890435@critter.freebsd.dk> References: <21494.1257890435@critter.freebsd.dk> Message-ID: <1382.41.130.184.218.1257917422.squirrel@webmail.lysator.liu.se> > In message > <2455.41.130.184.218.1257890017.squirrel at webmail.lysator.liu.se>, bg > @lysator.liu.se writes: > >>High performance mechanical rotating gyros are associated with platform >>systems. Ring laser gyros and fiber optic gyros are typically strapdown, >>which completely dominate modern navigation. > > Actually, they are usually strapped down to a deliberately moving > platform to avoid mode-lock-in at the mirrors, which produces a > "sticky" or "discrete steps" effect at slow rates of rotation. Most RLGs have a mechanical dither mechanism, but that is only moving the optical subsystem within the gyro. There is no platform at all for the accelerometers, and the three gyros typically do not use the same dither frequency. There are RLGs (Litton/NGC Zero Lock Gyro) that have no mechanical movement, they instead have an 'optical' dithering of one mirrors. FOGs have no moving parts at all. > But that is a minor detail. True. > Poul-Henning -- Bj?rn From rk at timing-consultants.com Wed Nov 11 09:41:38 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Wed, 11 Nov 2009 09:41:38 -0000 Subject: [time-nuts] Loran C shutdown In-Reply-To: <2074.12.6.201.54.1257903505.squirrel@popacctsnew.quik.com> References: <4AFA1520.5080609@aei.ca> <2074.12.6.201.54.1257903505.squirrel@popacctsnew.quik.com> Message-ID: Not practical. You need ground wave reception of LORAN for accurate navigation. At long distances you would be reliant on sky wave. I'm going to an NPL Timing meeting in early December being held at Trinity House in London. I'll get the low down on what is happening over here on LORAN in light of the US announcement for 2010. If anyone else in UK fancies the visit - got to http://www.npl.co.uk/events/timing-and-non-gnss-positions for info. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster Sent: 11 November 2009 01:38 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Loran C shutdown Also, somebody mentioned French chains. Any info on those would be appreciated. They might worl, especially on the east coast. -John ============== > Hello ! > > Before you throw away your Loran Receivers, have you checked what will > happen with the Canadian Transmitter Chains ? > > Would it be possible with better antennas to receive signals from other > countries ? > > Would be interested in hearing your input on these ideas ! > > Thanks ! > > Claude _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From ximac at btinternet.com Wed Nov 11 12:09:33 2009 From: ximac at btinternet.com (Joe McElvenney) Date: Wed, 11 Nov 2009 12:09:33 +0000 Subject: [time-nuts] SocketWatch Woes Message-ID: <469lf5d9qaegnl38dpg0gkfd6f00ivrlae@4ax.com> Hi, Does anyone on the list use SocketWatch to keep their computer's clock roughly up to snuff time-wise? With me having switched to Vista (and lately W7), it often can't make the necessary network connection and gives me 'access denied' messages. The strange thing is that it will work fine from a new installation but soon runs out of puff; maybe within the hour or within the day. Perhaps I haven't ticked the right boxes, so any pointers in this direction would be appreciated as there is no sign of any support for it. Yes, I know there are other products which do much the same thing but I've been using this utility for years and have become attached to it. Also I've got $10 invested in it and my mattress is empty :-) Cheers - Joe G3LLV From dave at uk-ar.co.uk Wed Nov 11 12:46:40 2009 From: dave at uk-ar.co.uk (Dave Baxter) Date: Wed, 11 Nov 2009 12:46:40 -0000 Subject: [time-nuts] Loran C shutdown In-Reply-To: Message-ID: Someone may correct me on this. But isn't Loran a parabolic navigation system? So, the further away from the chain of transmitters you are, the positioning "quality" (for want of a better word) will deteriorate. I seem to remember reading that you need a good spread of directions for the incoming signals, so you get a decent fix, much like clasic direction finding and reducing the area of uncertanty. Too far away, and all the bearings (timings in this case) tend to one direction. Any Sky Wave propagation would also mess with the timings, multi hop and all that. As above, I stand to be corrected on this. I may be thinking of another system of course. Regards. Dave G0WBX. > -----Original Message----- > Date: Tue, 10 Nov 2009 22:44:27 -0500 > From: paul swed > Subject: Re: [time-nuts] Loran C shutdown > To: Discussion of precise time and frequency measurement > > Message-ID: > > Content-Type: text/plain; charset=ISO-8859-1 > > Well that's what I am thinking about also. > Earlier in this thread there was a mention of Europe. > This would be a sky wave only signal as I recall from the navy. > So I have g3plx LORAN software and will look to see what I > might get here on the east coast. > Suspect the Canadian chains will go very quickly since part > of them uses the US chain. > Or simpler then the g3plx software, just plugging in the GRI > for the European chains. > Have 3 austron receivers, the 2000c, 2100, and 2100f. > > > On Tue, Nov 10, 2009 at 8:36 PM, Claude Houde wrote: > > > Hello ! > > > > Before you throw away your Loran Receivers, have you > checked what will > > happen with the Canadian Transmitter Chains ? > > > > Would it be possible with better antennas to receive signals from > > other countries ? > > > > Would be interested in hearing your input on these ideas ! > > > > Thanks ! > > > > Claude From paulswedb at gmail.com Wed Nov 11 14:01:11 2009 From: paulswedb at gmail.com (paul swed) Date: Wed, 11 Nov 2009 09:01:11 -0500 Subject: [time-nuts] Loran C shutdown In-Reply-To: <20091111045741.0x71fvkdckskwg0g@webmail.fc.up.pt> References: <4AFA1520.5080609@aei.ca> <20091111045741.0x71fvkdckskwg0g@webmail.fc.up.pt> Message-ID: Antonio, I ran into that last night. So much for an easy test. On Tue, Nov 10, 2009 at 10:57 PM, wrote: > The problem with the some European chains is that they have four-digit > GRPs . Therefore, the standard 2000C and maybe others are useless. > > Regards, > Antonio > CT1TE > > > Quoting paul swed : > > Well that's what I am thinking about also. >> Earlier in this thread there was a mention of Europe. >> This would be a sky wave only signal as I recall from the navy. >> So I have g3plx LORAN software and will look to see what I might get here >> on >> the east coast. >> Suspect the Canadian chains will go very quickly since part of them uses >> the >> US chain. >> Or simpler then the g3plx software, just plugging in the GRI for the >> European chains. >> Have 3 austron receivers, the 2000c, 2100, and 2100f. >> >> >> On Tue, Nov 10, 2009 at 8:36 PM, Claude Houde wrote: >> >> Hello ! >>> >>> Before you throw away your Loran Receivers, have you checked what will >>> happen with the Canadian Transmitter Chains ? >>> >>> Would it be possible with better antennas to receive signals from other >>> countries ? >>> >>> Would be interested in hearing your input on these ideas ! >>> >>> Thanks ! >>> >>> Claude >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > ------------------------------------------------------------------------- > A FCUP utiliza o sistema open source de webmail Horde/IMP (www.horde.org) > Visite: http://www.fc.up.pt/ http://info.fc.up.pt/ > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From mfsd at gmx.com Wed Nov 11 15:34:24 2009 From: mfsd at gmx.com (Mario Sanchez) Date: Wed, 11 Nov 2009 16:34:24 +0100 Subject: [time-nuts] DMTD using Active Mixers Message-ID: <20091111162441.204550@gmx.com> From mfsd at gmx.com Wed Nov 11 16:35:43 2009 From: mfsd at gmx.com (Mario Sanchez) Date: Wed, 11 Nov 2009 17:35:43 +0100 Subject: [time-nuts] DMTD using Active Mixers Message-ID: <20091111163543.204550@gmx.com> From mfsdlr at gmail.com Wed Nov 11 17:02:05 2009 From: mfsdlr at gmail.com (Mario Sanchez) Date: Wed, 11 Nov 2009 18:02:05 +0100 Subject: [time-nuts] DMTD using Active Mixers Message-ID: Hi all, I am starting building a DMTD, and for simplicity reasons I started with active mixers... What are the advantages/disadvantages of using passive mixers instead? Someone has had the experience to compare them? As LO, I am using a Synthesizer whose amplitude is approx 500mVpp, and the RF signal could be between 500mVpp - 2.8Vpp Thanks in advance for you input... Regards, Mario From jfor at quik.com Wed Nov 11 17:20:41 2009 From: jfor at quik.com (J. Forster) Date: Wed, 11 Nov 2009 09:20:41 -0800 (PST) Subject: [time-nuts] Loran C shutdown In-Reply-To: References: Message-ID: <1077.12.6.201.55.1257960041.squirrel@popacctsnew.quik.com> Hyperbolic, not parabolic. -John ======== > Someone may correct me on this. > > But isn't Loran a parabolic navigation system? So, the further away > from the chain of transmitters you are, the positioning "quality" (for > want of a better word) will deteriorate. I seem to remember reading > that you need a good spread of directions for the incoming signals, so > you get a decent fix, much like clasic direction finding and reducing > the area of uncertanty. Too far away, and all the bearings (timings in > this case) tend to one direction. > > Any Sky Wave propagation would also mess with the timings, multi hop and > all that. > > As above, I stand to be corrected on this. I may be thinking of another > system of course. > > Regards. > > Dave G0WBX. > > >> -----Original Message----- >> Date: Tue, 10 Nov 2009 22:44:27 -0500 >> From: paul swed >> Subject: Re: [time-nuts] Loran C shutdown >> To: Discussion of precise time and frequency measurement >> >> Message-ID: >> >> Content-Type: text/plain; charset=ISO-8859-1 >> >> Well that's what I am thinking about also. >> Earlier in this thread there was a mention of Europe. >> This would be a sky wave only signal as I recall from the navy. >> So I have g3plx LORAN software and will look to see what I >> might get here on the east coast. >> Suspect the Canadian chains will go very quickly since part >> of them uses the US chain. >> Or simpler then the g3plx software, just plugging in the GRI >> for the European chains. >> Have 3 austron receivers, the 2000c, 2100, and 2100f. >> >> >> On Tue, Nov 10, 2009 at 8:36 PM, Claude Houde wrote: >> >> > Hello ! >> > >> > Before you throw away your Loran Receivers, have you >> checked what will >> > happen with the Canadian Transmitter Chains ? >> > >> > Would it be possible with better antennas to receive signals from >> > other countries ? >> > >> > Would be interested in hearing your input on these ideas ! >> > >> > Thanks ! >> > >> > Claude > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From jfor at quik.com Wed Nov 11 18:46:58 2009 From: jfor at quik.com (J. Forster) Date: Wed, 11 Nov 2009 10:46:58 -0800 (PST) Subject: [time-nuts] Loran C shutdown Message-ID: <1208.12.6.201.55.1257965218.squirrel@popacctsnew.quik.com> > Not practical. You need ground wave reception of LORAN for accurate > navigation. At long distances you would be reliant on sky wave. Roy, OK, but my interest is NOT navigation, but as a standard of time interval. It would still be useful, even if the path length drifted between day and night as WWVB does. > I'm going to an NPL Timing meeting in early December being held at Trinity > House in London. I'll get the low down on what is happening over here on > LORAN in light of the US announcement for 2010. > > If anyone else in UK fancies the visit - got to > http://www.npl.co.uk/events/timing-and-non-gnss-positions for info. > > Rob Kimberley > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of J. Forster > Sent: 11 November 2009 01:38 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Loran C shutdown > > Also, somebody mentioned French chains. Any info on those would be > appreciated. They might worl, especially on the east coast. > > -John > > ============== > > >> Hello ! >> >> Before you throw away your Loran Receivers, have you checked what will >> happen with the Canadian Transmitter Chains ? >> >> Would it be possible with better antennas to receive signals from other >> countries ? >> >> Would be interested in hearing your input on these ideas ! >> >> Thanks ! >> >> Claude From brooke at pacific.net Wed Nov 11 20:01:55 2009 From: brooke at pacific.net (Brooke Clarke) Date: Wed, 11 Nov 2009 12:01:55 -0800 Subject: [time-nuts] Loran C shutdown In-Reply-To: <1208.12.6.201.55.1257965218.squirrel@popacctsnew.quik.com> References: <1208.12.6.201.55.1257965218.squirrel@popacctsnew.quik.com> Message-ID: <4AFB1833.3040900@pacific.net> Hi: As the distance between the transmitter and receiver increases so does the jitter in the received signal. You can see that in the data on the NIST page where they monitor different stations from Colorado. The greater the distance the poorer the time recovered. Have Fun, Brooke Clarke http://www.prc68.com J. Forster wrote: >> Not practical. You need ground wave reception of LORAN for accurate >> navigation. At long distances you would be reliant on sky wave. > > Roy, > > OK, but my interest is NOT navigation, but as a standard of time interval. > It would still be useful, even if the path length drifted between day and > night as WWVB does. > >> I'm going to an NPL Timing meeting in early December being held at Trinity >> House in London. I'll get the low down on what is happening over here on >> LORAN in light of the US announcement for 2010. >> >> If anyone else in UK fancies the visit - got to >> http://www.npl.co.uk/events/timing-and-non-gnss-positions for info. >> >> Rob Kimberley >> >> -----Original Message----- >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On >> Behalf Of J. Forster >> Sent: 11 November 2009 01:38 >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] Loran C shutdown >> >> Also, somebody mentioned French chains. Any info on those would be >> appreciated. They might worl, especially on the east coast. >> >> -John >> >> ============== >> >> >>> Hello ! >>> >>> Before you throw away your Loran Receivers, have you checked what will >>> happen with the Canadian Transmitter Chains ? >>> >>> Would it be possible with better antennas to receive signals from other >>> countries ? >>> >>> Would be interested in hearing your input on these ideas ! >>> >>> Thanks ! >>> >>> Claude > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From alan.melia at btinternet.com Wed Nov 11 20:09:31 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Wed, 11 Nov 2009 20:09:31 -0000 Subject: [time-nuts] Loran C shutdown References: <4AFA1520.5080609@aei.ca><2074.12.6.201.54.1257903505.squirrel@popacctsnew.quik.com> Message-ID: <008a01ca630a$e4367f40$0900a8c0@lark> Hi Rob I'm not sure yet but may see you there Alan Melia (G3NYK) ----- Original Message ----- From: "Rob Kimberley" To: ; "'Discussion of precise time and frequency measurement'" Sent: Wednesday, November 11, 2009 9:41 AM Subject: Re: [time-nuts] Loran C shutdown > Not practical. You need ground wave reception of LORAN for accurate > navigation. At long distances you would be reliant on sky wave. > > I'm going to an NPL Timing meeting in early December being held at Trinity > House in London. I'll get the low down on what is happening over here on > LORAN in light of the US announcement for 2010. > > If anyone else in UK fancies the visit - got to > http://www.npl.co.uk/events/timing-and-non-gnss-positions for info. > > Rob Kimberley > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of J. Forster > Sent: 11 November 2009 01:38 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Loran C shutdown > > Also, somebody mentioned French chains. Any info on those would be > appreciated. They might worl, especially on the east coast. > > -John > > ============== > > > > Hello ! > > > > Before you throw away your Loran Receivers, have you checked what will > > happen with the Canadian Transmitter Chains ? > > > > Would it be possible with better antennas to receive signals from other > > countries ? > > > > Would be interested in hearing your input on these ideas ! > > > > Thanks ! > > > > Claude > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From rk at timing-consultants.com Wed Nov 11 20:22:34 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Wed, 11 Nov 2009 20:22:34 -0000 Subject: [time-nuts] Loran C shutdown In-Reply-To: <008a01ca630a$e4367f40$0900a8c0@lark> References: <4AFA1520.5080609@aei.ca><2074.12.6.201.54.1257903505.squirrel@popacctsnew.quik.com> <008a01ca630a$e4367f40$0900a8c0@lark> Message-ID: <21C9B959BB7D426BAACF039685CA478D@robinHP> Hi Alan, I hope so. Peter Vince is coming. Rob -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Alan Melia Sent: 11 November 2009 20:10 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Loran C shutdown Hi Rob I'm not sure yet but may see you there Alan Melia (G3NYK) ----- Original Message ----- From: "Rob Kimberley" To: ; "'Discussion of precise time and frequency measurement'" Sent: Wednesday, November 11, 2009 9:41 AM Subject: Re: [time-nuts] Loran C shutdown > Not practical. You need ground wave reception of LORAN for accurate > navigation. At long distances you would be reliant on sky wave. > > I'm going to an NPL Timing meeting in early December being held at Trinity > House in London. I'll get the low down on what is happening over here on > LORAN in light of the US announcement for 2010. > > If anyone else in UK fancies the visit - got to > http://www.npl.co.uk/events/timing-and-non-gnss-positions for info. > > Rob Kimberley > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of J. Forster > Sent: 11 November 2009 01:38 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Loran C shutdown > > Also, somebody mentioned French chains. Any info on those would be > appreciated. They might worl, especially on the east coast. > > -John > > ============== > > > > Hello ! > > > > Before you throw away your Loran Receivers, have you checked what will > > happen with the Canadian Transmitter Chains ? > > > > Would it be possible with better antennas to receive signals from other > > countries ? > > > > Would be interested in hearing your input on these ideas ! > > > > Thanks ! > > > > Claude > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bruce.griffiths at xtra.co.nz Wed Nov 11 20:47:28 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 12 Nov 2009 09:47:28 +1300 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: References: Message-ID: <4AFB22E0.7000604@xtra.co.nz> Mario Sanchez wrote: > Hi all, > > > > I am starting building a DMTD, and for simplicity reasons I started with > active mixers... > > What are the advantages/disadvantages of using passive mixers instead? > Someone has had the experience to compare them? > > > > As LO, I am using a Synthesizer whose amplitude is approx 500mVpp, and the > RF signal could be between 500mVpp - 2.8Vpp > > > > Thanks in advance for you input... > > > > Regards, > Mario > Mario Active mixers almost invariably have a higher noise floor than passive mixers, particularly in the flicker noise region. Consequently a DMTD system using active mixers will have a higher system noise floor than one using active mixers. Bruce From magnus at rubidium.dyndns.org Wed Nov 11 21:32:21 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Wed, 11 Nov 2009 22:32:21 +0100 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <4AFB22E0.7000604@xtra.co.nz> References: <4AFB22E0.7000604@xtra.co.nz> Message-ID: <4AFB2D65.6050405@rubidium.dyndns.org> Bruce Griffiths wrote: > Active mixers almost invariably have a higher noise floor than passive > mixers, particularly in the flicker noise region. > Consequently a DMTD system using active mixers will have a higher system > noise floor than one using active mixers. ... than one using passive mixers. You still need driving amplifiers. Cheers, Magnus From rk at timing-consultants.com Wed Nov 11 22:05:49 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Wed, 11 Nov 2009 22:05:49 -0000 Subject: [time-nuts] Home NTP ? & GPS Clock s/w In-Reply-To: <26014.206.174.20.67.1257671067.squirrel@mymail.acsalaska.net> References: <935512.98003.qm@web65715.mail.ac4.yahoo.com> <26014.206.174.20.67.1257671067.squirrel@mymail.acsalaska.net> Message-ID: <0A7F847B62504B7B82869DAAA1E492BF@robinHP> Or just use NTP for Windows - available for free at http://www.meinberg.de/english/sw/ntp.htm. Use it in conjunction with their excellent NTP Monitor program http://www.meinberg.de/english/sw/time-server-monitor.htm Works a treat on any Windows machine. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Richard H McCorkle Sent: 08 November 2009 09:04 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Home NTP ? & GPS Clock s/w Ray, For a simple solution with WinDoze machines take a look at Tardis 2000 at http://www.kaska.demon.co.uk as a possible approach. Tardis can get NTP time from the internet or use a GPS NEMA message to sync the time server and reboadcast NTP on your local LAN. The K9 client can be used on the other machines to keep them in sync. Its free to try with no nag screens so the price is right. Richard > > Can anyone suggest how to setup a 'home' NTP server under windows (useing WAMP or > similar). This is just for use on a home LAN. > Please no linux suggestions as I know they exist. > > Also does anyone know a good (free) GPS clock for windows (synced to com port or > NTP server) > > Thanks Ray, VK4TFT > > > ____________________________________________________________________________ ______ > Win 1 of 4 Sony home entertainment packs thanks to Yahoo!7. > Enter now: http://au.docs.yahoo.com/homepageset/ > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bruce.griffiths at xtra.co.nz Wed Nov 11 22:07:18 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 12 Nov 2009 11:07:18 +1300 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <4AFB2D65.6050405@rubidium.dyndns.org> References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> Message-ID: <4AFB3596.2040803@xtra.co.nz> Magnus Danielson wrote: > Bruce Griffiths wrote: >> Active mixers almost invariably have a higher noise floor than >> passive mixers, particularly in the flicker noise region. >> Consequently a DMTD system using active mixers will have a higher >> system noise floor than one using active mixers. > > ... than one using passive mixers. > > You still need driving amplifiers. > > Cheers, > Magnus > Its much easier to ensure that the flicker phase noise of a buffer amplifier is low than it is to achieve a low flicker phase noise for an mixer using nonlinear active devices. Even passive FET mixers have higher flicker noise than passive mixers using schottky diodes. Bruce From magnus at rubidium.dyndns.org Wed Nov 11 22:15:27 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Wed, 11 Nov 2009 23:15:27 +0100 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <4AFB3596.2040803@xtra.co.nz> References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> <4AFB3596.2040803@xtra.co.nz> Message-ID: <4AFB377F.7040406@rubidium.dyndns.org> Bruce Griffiths wrote: > Magnus Danielson wrote: >> Bruce Griffiths wrote: >>> Active mixers almost invariably have a higher noise floor than >>> passive mixers, particularly in the flicker noise region. >>> Consequently a DMTD system using active mixers will have a higher >>> system noise floor than one using active mixers. >> >> ... than one using passive mixers. >> >> You still need driving amplifiers. >> >> Cheers, >> Magnus >> > Its much easier to ensure that the flicker phase noise of a buffer > amplifier is low than it is to achieve a low flicker phase noise for an > mixer using nonlinear active devices. > Even passive FET mixers have higher flicker noise than passive mixers > using schottky diodes. True, but my comment was rather to say that it will most probably not be all passive, but I completely agree (as you very well know) that phase noise of amplifiers is much better contained than that of mixers. Cheers, Magnus From bruce.griffiths at xtra.co.nz Wed Nov 11 22:30:12 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 12 Nov 2009 11:30:12 +1300 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <4AFB377F.7040406@rubidium.dyndns.org> References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> <4AFB3596.2040803@xtra.co.nz> <4AFB377F.7040406@rubidium.dyndns.org> Message-ID: <4AFB3AF4.7080801@xtra.co.nz> Magnus Danielson wrote: > Bruce Griffiths wrote: >> Magnus Danielson wrote: >>> Bruce Griffiths wrote: >>>> Active mixers almost invariably have a higher noise floor than >>>> passive mixers, particularly in the flicker noise region. >>>> Consequently a DMTD system using active mixers will have a higher >>>> system noise floor than one using active mixers. >>> >>> ... than one using passive mixers. >>> >>> You still need driving amplifiers. >>> >>> Cheers, >>> Magnus >>> >> Its much easier to ensure that the flicker phase noise of a buffer >> amplifier is low than it is to achieve a low flicker phase noise for >> an mixer using nonlinear active devices. >> Even passive FET mixers have higher flicker noise than passive mixers >> using schottky diodes. > > True, but my comment was rather to say that it will most probably not > be all passive, but I completely agree (as you very well know) that > phase noise of amplifiers is much better contained than that of mixers. > > Cheers, > Magnus > Hej Magnus To confuse matters Minicircuits use the term active mixer for a conventional diode mixer that uses amplifiers on the LO and/or RF ports to boost signal levels. Whereas I was referring to mixers like gilbert cell mixers as active mixers. With the Minicircuits so called active mixers one needs to measure their phase noise in order to make meaningful comparisons. Bruce Bruce From rk at timing-consultants.com Wed Nov 11 22:31:45 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Wed, 11 Nov 2009 22:31:45 -0000 Subject: [time-nuts] SocketWatch Woes In-Reply-To: <469lf5d9qaegnl38dpg0gkfd6f00ivrlae@4ax.com> References: <469lf5d9qaegnl38dpg0gkfd6f00ivrlae@4ax.com> Message-ID: <072C02C4B9E94A96A496C858EFFAEEE9@robinHP> Have you tried Dimension 4 Time? See http://www.thinkman.com/dimension4/. Free download for private use. Have used it on XP and Vista machines OK. Don't know about Windoze 7 though. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Joe McElvenney Sent: 11 November 2009 12:10 To: Time Nuts Digest Subject: [time-nuts] SocketWatch Woes Hi, Does anyone on the list use SocketWatch to keep their computer's clock roughly up to snuff time-wise? With me having switched to Vista (and lately W7), it often can't make the necessary network connection and gives me 'access denied' messages. The strange thing is that it will work fine from a new installation but soon runs out of puff; maybe within the hour or within the day. Perhaps I haven't ticked the right boxes, so any pointers in this direction would be appreciated as there is no sign of any support for it. Yes, I know there are other products which do much the same thing but I've been using this utility for years and have become attached to it. Also I've got $10 invested in it and my mattress is empty :-) Cheers - Joe G3LLV _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Thu Nov 12 00:39:02 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 12 Nov 2009 01:39:02 +0100 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <4AFB3AF4.7080801@xtra.co.nz> References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> <4AFB3596.2040803@xtra.co.nz> <4AFB377F.7040406@rubidium.dyndns.org> <4AFB3AF4.7080801@xtra.co.nz> Message-ID: <4AFB5926.4010804@rubidium.dyndns.org> Bruce Griffiths wrote: > Hej Magnus > > To confuse matters Minicircuits use the term active mixer for a > conventional diode mixer that uses amplifiers on the LO and/or RF ports > to boost signal levels. While it confuses matters, it is usefull to know about them, since they may be good for some designs, but maybe not for DMTD designs. I have argued that keeping a buffer-amplifiers (not to be confused with the -120 dB isolational amp) just at the mixer will relief the issues of VSWR to tempco. Also, getting that extra boost is also good. Needs to have meaningfull phasenoise to be usefull thought. > Whereas I was referring to mixers like gilbert cell mixers as active > mixers. I was making the same distinction. Passive JFET mixers is just another variant to using schottkydiodes. > With the Minicircuits so called active mixers one needs to measure > their phase noise in order to make meaningful comparisons. Indeed. Their target is probably not considering cutting edge DMTD systems. Cheers, Magnus From lists at cq.nu Thu Nov 12 01:55:09 2009 From: lists at cq.nu (Bob Camp) Date: Wed, 11 Nov 2009 20:55:09 -0500 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <4AFB5926.4010804@rubidium.dyndns.org> References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> <4AFB3596.2040803@xtra.co.nz> <4AFB377F.7040406@rubidium.dyndns.org> <4AFB3AF4.7080801@xtra.co.nz> <4AFB5926.4010804@rubidium.dyndns.org> Message-ID: <81D8EB91-7EA5-4C13-9FE6-0A55C9AD39C2@cq.nu> HI I have no direct experience with the Minicircuits "active mixers", but I have used some of their amplifier chips. I suspect they use their own amps. The amps I worked with had significant phase noise issues when driven within 6db of their 1db compression point. They were "ok" at low drive levels. More or less then went from 3 db noise figure to a > 20 db nf as you went from -20 dbm to 0 dbm output on a +7 dbm amplifier. Bob On Nov 11, 2009, at 7:39 PM, Magnus Danielson wrote: > Bruce Griffiths wrote: >> Hej Magnus >> To confuse matters Minicircuits use the term active mixer for a >> conventional diode mixer that uses amplifiers on the LO and/or RF >> ports to boost signal levels. > > While it confuses matters, it is usefull to know about them, since > they may be good for some designs, but maybe not for DMTD designs. > > I have argued that keeping a buffer-amplifiers (not to be confused > with the -120 dB isolational amp) just at the mixer will relief the > issues of VSWR to tempco. Also, getting that extra boost is also > good. Needs to have meaningfull phasenoise to be usefull thought. > >> Whereas I was referring to mixers like gilbert cell mixers as >> active mixers. > > I was making the same distinction. Passive JFET mixers is just > another variant to using schottkydiodes. > >> With the Minicircuits so called active mixers one needs to measure >> their phase noise in order to make meaningful comparisons. > > Indeed. Their target is probably not considering cutting edge DMTD > systems. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From glennmaillist at bellsouth.net Thu Nov 12 05:40:14 2009 From: glennmaillist at bellsouth.net (Glenn Little WB4UIV) Date: Thu, 12 Nov 2009 00:40:14 -0500 Subject: [time-nuts] Rubidium standard Message-ID: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> I was told by a Technical Support Engineer from Symmetricom Global Services that "The typical life span is ~10 years for these Rubidium Time Bases". This is in response to my request for information on a Ball/Efratom PTB-100. Is this a typical life span of a rubidium standard? Do some standards last longer than others? What are the symptoms of a failing rubidium bulb? Thanks 73 Glenn WB4UIV From magnus at rubidium.dyndns.org Thu Nov 12 06:13:21 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Thu, 12 Nov 2009 07:13:21 +0100 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <81D8EB91-7EA5-4C13-9FE6-0A55C9AD39C2@cq.nu> References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> <4AFB3596.2040803@xtra.co.nz> <4AFB377F.7040406@rubidium.dyndns.org> <4AFB3AF4.7080801@xtra.co.nz> <4AFB5926.4010804@rubidium.dyndns.org> <81D8EB91-7EA5-4C13-9FE6-0A55C9AD39C2@cq.nu> Message-ID: <4AFBA781.9090306@rubidium.dyndns.org> Bob Camp wrote: > HI > > I have no direct experience with the Minicircuits "active mixers", but I > have used some of their amplifier chips. I suspect they use their own amps. Or at least the same amps. > The amps I worked with had significant phase noise issues when driven > within 6db of their 1db compression point. They were "ok" at low drive > levels. More or less then went from 3 db noise figure to a > 20 db nf as > you went from -20 dbm to 0 dbm output on a +7 dbm amplifier. Uhm, that sounds more like distorsion than noise. Anyway, if it is the same amps, then that would exclude them from being suitable for driving the mixer to saturation. Thanks for the report. Cheers, Magnus From hmurray at megapathdsl.net Thu Nov 12 07:15:44 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Wed, 11 Nov 2009 23:15:44 -0800 Subject: [time-nuts] Rubidium standard In-Reply-To: Message from Glenn Little WB4UIV of "Thu, 12 Nov 2009 00:40:14 EST." <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> Message-ID: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> > I was told by a Technical Support Engineer from Symmetricom Global > Services that "The typical life span is ~10 years for these Rubidium > Time Bases". > This is in response to my request for information on a Ball/Efratom > PTB-100. > Is this a typical life span of a rubidium standard? It's lower than what I would expect. The target market is the Telco and Cell Phone industry. They expect (or at least used to) long lifetimes. Maybe "life span" means how long they run it, planning to replace it with newer gear long before it actually wears out. I would have expected more like 20 years of useful life. That's running 24x7 in a reasonable environment. That's also with hacker reliability, aka it's not a disaster if it dies. So if you get one that was dumped by a Telco after 10 years, it's not crazy to run it 24x7 and expect many more years. (Just as long as you don't go crazy if it doesn't last that long. I can buy a lot of surplus stuff for the price of new gear as long as I'm willing to tolerate the time gaps and effort of replacing it when it dies.) The LPRO-101 blurb says: Amb.Temp: 20 ?C 25 ?C 30 ?C 40 ?C 50 ?C 60 ?C MTBF (hrs) 381k 351k 320k 253k 189k 134k A year is 8760 hours (ignoring leap years). Call that 10K. So they expect 25 years at 40C and 32 years at 30C. That's calculated MTBF. YMMV. > Do some standards last longer than others? I'm sure some are better than others. I don't have any data. > What are the symptoms of a failing rubidium bulb? Externally? It stops working. The error signal (maybe a LED too) will go on, or rather the locked signal (open collector?) will go off. The frequency stability will fall off a cliff. -- These are my opinions, not necessarily my employer's. I hate spam. From w6te at msn.com Thu Nov 12 07:31:58 2009 From: w6te at msn.com (David Smith) Date: Wed, 11 Nov 2009 23:31:58 -0800 Subject: [time-nuts] Rubidium standard In-Reply-To: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: I'm new to the list. Having said that, I ran across a webpage from a chap in Australia or maybe it was New Zealand. In any event he claims that the Rb lamp can be brought back to life. He says that he has rejuvenated over 30 units with bad lamps and they work great after his "process." I will try and dig up the webpage if anyone is interested. Dave / W6TE ----- Original Message ----- From: Hal Murray To: Discussion of precise time and frequency measurement Sent: Wednesday, November 11, 2009 11:15 PM Subject: Re: [time-nuts] Rubidium standard > I was told by a Technical Support Engineer from Symmetricom Global > Services that "The typical life span is ~10 years for these Rubidium > Time Bases". > This is in response to my request for information on a Ball/Efratom > PTB-100. > Is this a typical life span of a rubidium standard? It's lower than what I would expect. The target market is the Telco and Cell Phone industry. They expect (or at least used to) long lifetimes. Maybe "life span" means how long they run it, planning to replace it with newer gear long before it actually wears out. I would have expected more like 20 years of useful life. That's running 24x7 in a reasonable environment. That's also with hacker reliability, aka it's not a disaster if it dies. So if you get one that was dumped by a Telco after 10 years, it's not crazy to run it 24x7 and expect many more years. (Just as long as you don't go crazy if it doesn't last that long. I can buy a lot of surplus stuff for the price of new gear as long as I'm willing to tolerate the time gaps and effort of replacing it when it dies.) The LPRO-101 blurb says: Amb.Temp: 20 ?C 25 ?C 30 ?C 40 ?C 50 ?C 60 ?C MTBF (hrs) 381k 351k 320k 253k 189k 134k A year is 8760 hours (ignoring leap years). Call that 10K. So they expect 25 years at 40C and 32 years at 30C. That's calculated MTBF. YMMV. > Do some standards last longer than others? I'm sure some are better than others. I don't have any data. > What are the symptoms of a failing rubidium bulb? Externally? It stops working. The error signal (maybe a LED too) will go on, or rather the locked signal (open collector?) will go off. The frequency stability will fall off a cliff. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From fortime at bellsouth.net Thu Nov 12 08:27:37 2009 From: fortime at bellsouth.net (phil) Date: Thu, 12 Nov 2009 03:27:37 -0500 Subject: [time-nuts] Rubidium standard References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <06F48D49E69D48D59499345A71F41403@devoffice> ----- Original Message ----- From: "David Smith" To: "Discussion of precise time and frequency measurement" Sent: Thursday, November 12, 2009 2:31 AM Subject: Re: [time-nuts] Rubidium standard I'm new to the list. Having said that, I ran across a webpage from a chap in Australia or maybe it was New Zealand. In any event he claims that the Rb lamp can be brought back to life. He says that he has rejuvenated over 30 units with bad lamps and they work great after his "process." I will try and dig up the webpage if anyone is interested. Dave / W6TE ----- Original Message ----- From: Hal Murray To: Discussion of precise time and frequency measurement Sent: Wednesday, November 11, 2009 11:15 PM Subject: Re: [time-nuts] Rubidium standard > I was told by a Technical Support Engineer from Symmetricom Global > Services that "The typical life span is ~10 years for these Rubidium > Time Bases". > This is in response to my request for information on a Ball/Efratom > PTB-100. > Is this a typical life span of a rubidium standard? It's lower than what I would expect. The target market is the Telco and Cell Phone industry. They expect (or at least used to) long lifetimes. Maybe "life span" means how long they run it, planning to replace it with newer gear long before it actually wears out. I would have expected more like 20 years of useful life. That's running 24x7 in a reasonable environment. That's also with hacker reliability, aka it's not a disaster if it dies. So if you get one that was dumped by a Telco after 10 years, it's not crazy to run it 24x7 and expect many more years. (Just as long as you don't go crazy if it doesn't last that long. I can buy a lot of surplus stuff for the price of new gear as long as I'm willing to tolerate the time gaps and effort of replacing it when it dies.) The LPRO-101 blurb says: Amb.Temp: 20 ?C 25 ?C 30 ?C 40 ?C 50 ?C 60 ?C MTBF (hrs) 381k 351k 320k 253k 189k 134k A year is 8760 hours (ignoring leap years). Call that 10K. So they expect 25 years at 40C and 32 years at 30C. That's calculated MTBF. YMMV. > Do some standards last longer than others? I'm sure some are better than others. I don't have any data. > What are the symptoms of a failing rubidium bulb? Externally? It stops working. The error signal (maybe a LED too) will go on, or rather the locked signal (open collector?) will go off. The frequency stability will fall off a cliff. "He says that he has rejuvenated over 30 units with bad lamps and they work great after his "process." " Is this what you were referring to? Near the end he explains how to "rejuvenate" lamps. http://www.febo.com/pipermail/time-nuts/attachments/20081103/c205b683/attachment.pdf From w6te at msn.com Thu Nov 12 08:31:30 2009 From: w6te at msn.com (David Smith) Date: Thu, 12 Nov 2009 00:31:30 -0800 Subject: [time-nuts] Rubidium standard In-Reply-To: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> Message-ID: Yes, that's the page . Thanks, Dave ----- Original Message ----- From: phil To: Discussion of precise time and frequency measurement Sent: Thursday, November 12, 2009 12:27 AM Subject: Re: [time-nuts] Rubidium standard ----- Original Message ----- From: "David Smith" > To: "Discussion of precise time and frequency measurement" > Sent: Thursday, November 12, 2009 2:31 AM Subject: Re: [time-nuts] Rubidium standard I'm new to the list. Having said that, I ran across a webpage from a chap in Australia or maybe it was New Zealand. In any event he claims that the Rb lamp can be brought back to life. He says that he has rejuvenated over 30 units with bad lamps and they work great after his "process." I will try and dig up the webpage if anyone is interested. Dave / W6TE ----- Original Message ----- From: Hal Murray> To: Discussion of precise time and frequency measurement> Sent: Wednesday, November 11, 2009 11:15 PM Subject: Re: [time-nuts] Rubidium standard > I was told by a Technical Support Engineer from Symmetricom Global > Services that "The typical life span is ~10 years for these Rubidium > Time Bases". > This is in response to my request for information on a Ball/Efratom > PTB-100. > Is this a typical life span of a rubidium standard? It's lower than what I would expect. The target market is the Telco and Cell Phone industry. They expect (or at least used to) long lifetimes. Maybe "life span" means how long they run it, planning to replace it with newer gear long before it actually wears out. I would have expected more like 20 years of useful life. That's running 24x7 in a reasonable environment. That's also with hacker reliability, aka it's not a disaster if it dies. So if you get one that was dumped by a Telco after 10 years, it's not crazy to run it 24x7 and expect many more years. (Just as long as you don't go crazy if it doesn't last that long. I can buy a lot of surplus stuff for the price of new gear as long as I'm willing to tolerate the time gaps and effort of replacing it when it dies.) The LPRO-101 blurb says: Amb.Temp: 20 ?C 25 ?C 30 ?C 40 ?C 50 ?C 60 ?C MTBF (hrs) 381k 351k 320k 253k 189k 134k A year is 8760 hours (ignoring leap years). Call that 10K. So they expect 25 years at 40C and 32 years at 30C. That's calculated MTBF. YMMV. > Do some standards last longer than others? I'm sure some are better than others. I don't have any data. > What are the symptoms of a failing rubidium bulb? Externally? It stops working. The error signal (maybe a LED too) will go on, or rather the locked signal (open collector?) will go off. The frequency stability will fall off a cliff. "He says that he has rejuvenated over 30 units with bad lamps and they work great after his "process." " Is this what you were referring to? Near the end he explains how to "rejuvenate" lamps. http://www.febo.com/pipermail/time-nuts/attachments/20081103/c205b683/attachment.pdf _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From dave at uk-ar.co.uk Thu Nov 12 08:48:07 2009 From: dave at uk-ar.co.uk (Dave Baxter) Date: Thu, 12 Nov 2009 08:48:07 -0000 Subject: [time-nuts] Loran C shutdown In-Reply-To: Message-ID: Thanks John... It was pre my usual caffine intake... Dave G0WBX. > -----Original Message----- > From: "J. Forster" > Subject: Re: [time-nuts] Loran C shutdown > > Hyperbolic, not parabolic. > > -John > > ======== > > > Someone may correct me on this. > > > > But isn't Loran a parabolic navigation system? So, the further away > > from the chain of transmitters you are, the positioning "quality" (for > > want of a better word) will deteriorate. From mfsdlr at gmail.com Thu Nov 12 09:16:32 2009 From: mfsdlr at gmail.com (Mario Sanchez) Date: Thu, 12 Nov 2009 10:16:32 +0100 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: <4AFB5926.4010804@rubidium.dyndns.org> References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> <4AFB3596.2040803@xtra.co.nz> <4AFB377F.7040406@rubidium.dyndns.org> <4AFB3AF4.7080801@xtra.co.nz> <4AFB5926.4010804@rubidium.dyndns.org> Message-ID: Thanks for your inputs... I dont know exactly which are the microcircuits ActiveMixers you refer to; just to make it clear, the IC that I am using is Analog Devices AD831, which basically has a conventional diode mixer, a limiter amplifier in the LO input and a low noise output amplifier. Regards, Mario On Thu, Nov 12, 2009 at 1:39 AM, Magnus Danielson < magnus at rubidium.dyndns.org> wrote: > Bruce Griffiths wrote: > >> Hej Magnus >> >> To confuse matters Minicircuits use the term active mixer for a >> conventional diode mixer that uses amplifiers on the LO and/or RF ports to >> boost signal levels. >> > > While it confuses matters, it is usefull to know about them, since they may > be good for some designs, but maybe not for DMTD designs. > > I have argued that keeping a buffer-amplifiers (not to be confused with the > -120 dB isolational amp) just at the mixer will relief the issues of VSWR to > tempco. Also, getting that extra boost is also good. Needs to have > meaningfull phasenoise to be usefull thought. > > > Whereas I was referring to mixers like gilbert cell mixers as active >> mixers. >> > > I was making the same distinction. Passive JFET mixers is just another > variant to using schottkydiodes. > > > With the Minicircuits so called active mixers one needs to measure their >> phase noise in order to make meaningful comparisons. >> > > Indeed. Their target is probably not considering cutting edge DMTD systems. > > Cheers, > Magnus > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From bruce.griffiths at xtra.co.nz Thu Nov 12 09:35:58 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 12 Nov 2009 22:35:58 +1300 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: References: <4AFB22E0.7000604@xtra.co.nz> <4AFB2D65.6050405@rubidium.dyndns.org> <4AFB3596.2040803@xtra.co.nz> <4AFB377F.7040406@rubidium.dyndns.org> <4AFB3AF4.7080801@xtra.co.nz> <4AFB5926.4010804@rubidium.dyndns.org> Message-ID: <4AFBD6FE.2060506@xtra.co.nz> Mario No there is no diode mixer in the AD831, it uses a conventional Gilbert cell mixer with preceding LO and RF amplifiers. Compared to a diode mixer it has high flicker noise and poor dc stability. Bruce Mario Sanchez wrote: > Thanks for your inputs... > > I dont know exactly which are the microcircuits ActiveMixers you refer to; > just to make it clear, the IC that I am using is Analog Devices AD831, which > basically has a conventional diode mixer, a limiter amplifier in the LO > input and a low noise output amplifier. > > Regards, > Mario > > > On Thu, Nov 12, 2009 at 1:39 AM, Magnus Danielson< > magnus at rubidium.dyndns.org> wrote: > > >> Bruce Griffiths wrote: >> >> >>> Hej Magnus >>> >>> To confuse matters Minicircuits use the term active mixer for a >>> conventional diode mixer that uses amplifiers on the LO and/or RF ports to >>> boost signal levels. >>> >>> >> While it confuses matters, it is usefull to know about them, since they may >> be good for some designs, but maybe not for DMTD designs. >> >> I have argued that keeping a buffer-amplifiers (not to be confused with the >> -120 dB isolational amp) just at the mixer will relief the issues of VSWR to >> tempco. Also, getting that extra boost is also good. Needs to have >> meaningfull phasenoise to be usefull thought. >> >> >> Whereas I was referring to mixers like gilbert cell mixers as active >> >>> mixers. >>> >>> >> I was making the same distinction. Passive JFET mixers is just another >> variant to using schottkydiodes. >> >> >> With the Minicircuits so called active mixers one needs to measure their >> >>> phase noise in order to make meaningful comparisons. >>> >>> >> Indeed. Their target is probably not considering cutting edge DMTD systems. >> >> Cheers, >> Magnus >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From EWKehren at aol.com Thu Nov 12 11:13:11 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Thu, 12 Nov 2009 06:13:11 EST Subject: [time-nuts] DMTD using Active Mixers Message-ID: On our DMTD I am using Minicircuit amplifiers and the SYPD-1 phase detector. Corby is presently testing the unit and we see about 2 E -13. Let me stress again I am not trying to push for the absolute best performance, my focus is on simplicity, cost and ease to reproduce. The goal is 1 E -13. Cost goal of $ 200 has been achieved. That includes the five channel counter where Richard has finished the PIC programming and modifications to the PC boards have been implemented. Corby is looking at what it will take to get to the performance of the NBS unit, which is our baseline. I think this unit will serve 99% of us well since it not only shows Alan Variance but frequency difference directly. Resolution is 1 E -15. Bert Kehren In a message dated 11/12/2009 1:14:08 A.M. Eastern Standard Time, magnus at rubidium.dyndns.org writes: Bob Camp wrote: > HI > > I have no direct experience with the Minicircuits "active mixers", but I > have used some of their amplifier chips. I suspect they use their own amps. Or at least the same amps. > The amps I worked with had significant phase noise issues when driven > within 6db of their 1db compression point. They were "ok" at low drive > levels. More or less then went from 3 db noise figure to a > 20 db nf as > you went from -20 dbm to 0 dbm output on a +7 dbm amplifier. Uhm, that sounds more like distorsion than noise. Anyway, if it is the same amps, then that would exclude them from being suitable for driving the mixer to saturation. Thanks for the report. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From mfsdlr at gmail.com Thu Nov 12 11:57:04 2009 From: mfsdlr at gmail.com (Mario Sanchez) Date: Thu, 12 Nov 2009 12:57:04 +0100 Subject: [time-nuts] DMTD using Active Mixers In-Reply-To: References: Message-ID: Hi Bert, * The 2E-13 you talk about is ADEV at Tau = 1s, or...? * What kind of set-up you are using to measure it? Thanks and best regards, Mario On Thu, Nov 12, 2009 at 12:13 PM, wrote: > On our DMTD I am using Minicircuit amplifiers and the SYPD-1 phase > detector. Corby is presently testing the unit and we see about 2 E -13. Let > me > stress again I am not trying to push for the absolute best performance, my > focus is on simplicity, cost and ease to reproduce. The goal is 1 E -13. > Cost > goal of $ 200 has been achieved. That includes the five channel counter > where Richard has finished the PIC programming and modifications to the PC > boards have been implemented. Corby is looking at what it will take to get > to > the performance of the NBS unit, which is our baseline. I think this unit > will serve 99% of us well since it not only shows Alan Variance but > frequency > difference directly. Resolution is 1 E -15. > Bert Kehren > > > In a message dated 11/12/2009 1:14:08 A.M. Eastern Standard Time, > magnus at rubidium.dyndns.org writes: > > Bob Camp wrote: > > HI > > > > I have no direct experience with the Minicircuits "active mixers", but I > > have used some of their amplifier chips. I suspect they use their own > amps. > > Or at least the same amps. > > > The amps I worked with had significant phase noise issues when driven > > within 6db of their 1db compression point. They were "ok" at low drive > > levels. More or less then went from 3 db noise figure to a > 20 db nf as > > you went from -20 dbm to 0 dbm output on a +7 dbm amplifier. > > Uhm, that sounds more like distorsion than noise. Anyway, if it is the > same amps, then that would exclude them from being suitable for driving > the mixer to saturation. Thanks for the report. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From mikes at flatsurface.com Thu Nov 12 12:50:44 2009 From: mikes at flatsurface.com (Mike S) Date: Thu, 12 Nov 2009 07:50:44 -0500 Subject: [time-nuts] Rubidium standard In-Reply-To: References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> Message-ID: <20091112125151.695AE1165C1@hamburg.alientech.net> At 03:31 AM 11/12/2009, David Smith wrote... > The LPRO-101 blurb says: > Amb.Temp: 20 ?C 25 ?C 30 ?C 40 ?C 50 ?C 60 ?C > MTBF (hrs) 381k 351k 320k 253k 189k 134k > > A year is 8760 hours (ignoring leap > years). Call that 10K. So they > expect > 25 years at 40C and 32 years at 30C. > > That's calculated MTBF. YMMV. I'm sure someone with more statistics background can add to this, but useful (or expected) lifetime cannot be determined from an MTBF number. Here's an example I found, demonstrating this: "There are 500,000 25-year-old humans in the sample population. Over the course of a year, data is collected on failures (deaths) for this population. The operational life of the population is 500,000 x 1 year = 500,000 people years. Throughout the year, 625 people failed (died). The failure rate is 625 failures / 500,000 people years = 0.125% / year. The MTBF is the inverse of failure rate or 1 / 0.00125 = 800 years. So, even though 25-year-old humans have high MTBF values, their life expectancy (service life) is much shorter and does not correlate." From EWKehren at aol.com Thu Nov 12 13:31:04 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Thu, 12 Nov 2009 08:31:04 EST Subject: [time-nuts] DMTD using Active Mixers Message-ID: It is 1 second and Corby uses his Maser, he has done many tests in the past and he has an original NBS unit and is able to go back and forth. The system is set up in such a way that you can also use .1 and .01 seconds. Bert In a message dated 11/12/2009 6:58:02 A.M. Eastern Standard Time, mfsdlr at gmail.com writes: Hi Bert, * The 2E-13 you talk about is ADEV at Tau = 1s, or...? * What kind of set-up you are using to measure it? Thanks and best regards, Mario On Thu, Nov 12, 2009 at 12:13 PM, wrote: > On our DMTD I am using Minicircuit amplifiers and the SYPD-1 phase > detector. Corby is presently testing the unit and we see about 2 E -13. Let > me > stress again I am not trying to push for the absolute best performance, my > focus is on simplicity, cost and ease to reproduce. The goal is 1 E -13. > Cost > goal of $ 200 has been achieved. That includes the five channel counter > where Richard has finished the PIC programming and modifications to the PC > boards have been implemented. Corby is looking at what it will take to get > to > the performance of the NBS unit, which is our baseline. I think this unit > will serve 99% of us well since it not only shows Alan Variance but > frequency > difference directly. Resolution is 1 E -15. > Bert Kehren > > > In a message dated 11/12/2009 1:14:08 A.M. Eastern Standard Time, > magnus at rubidium.dyndns.org writes: > > Bob Camp wrote: > > HI > > > > I have no direct experience with the Minicircuits "active mixers", but I > > have used some of their amplifier chips. I suspect they use their own > amps. > > Or at least the same amps. > > > The amps I worked with had significant phase noise issues when driven > > within 6db of their 1db compression point. They were "ok" at low drive > > levels. More or less then went from 3 db noise figure to a > 20 db nf as > > you went from -20 dbm to 0 dbm output on a +7 dbm amplifier. > > Uhm, that sounds more like distorsion than noise. Anyway, if it is the > same amps, then that would exclude them from being suitable for driving > the mixer to saturation. Thanks for the report. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From paulswedb at gmail.com Thu Nov 12 15:33:30 2009 From: paulswedb at gmail.com (paul swed) Date: Thu, 12 Nov 2009 10:33:30 -0500 Subject: [time-nuts] Rubidium standard In-Reply-To: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> References: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> Message-ID: Glenn, I believe thats the case. I have a number of the small x cel tower rbs. You can nurse them a bit. But the failures I have run into are other things. Like the tuning cap on the lamp exciter getting noisy Also I have found re-peaking the multiplier chain can help It definitely stretches the life a bit. I would bet things like bypass caps fit into the failures also. 10 years is a long time for these itty bitty electrolytic s. No reserve like the older ones. Plus they are just fun to play with to try to recover them. I see date codes like 94-03 on the stuff that I get. So they are long in the tooth as it is. Now the old HP5065 1985 still is going strong. Believe thats because there simply is more of everything. Gas caps... Built like a tank. regards On Thu, Nov 12, 2009 at 12:40 AM, Glenn Little WB4UIV < glennmaillist at bellsouth.net> wrote: > I was told by a Technical Support Engineer from Symmetricom Global Services > that > "The typical life span is ~10 years for these Rubidium Time Bases". > > This is in response to my request for information on a Ball/Efratom > PTB-100. > > Is this a typical life span of a rubidium standard? > > Do some standards last longer than others? > > What are the symptoms of a failing rubidium bulb? > > Thanks > 73 > Glenn > WB4UIV > > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From phill.r1 at btinternet.com Thu Nov 12 16:21:02 2009 From: phill.r1 at btinternet.com (Roy Phillips) Date: Thu, 12 Nov 2009 16:21:02 -0000 Subject: [time-nuts] Rubidium standard In-Reply-To: References: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> Message-ID: <91ABA59FB875433C9F6E5BC83DA4534B@LapTop> Glenn I understand that manufactures may state that a Rubidium unit is good for ten years, but they do not necessarily support this claim with their warranties, which at best are for three years, and most are one year only. It seems that ten years of working life is likely, and perhaps this is why used FRS. are probably better purchased from a ex. military source as they probably have not been in continuous use, in fact they are often sitting on a shelf for five or more years before being disposed off. regards Roy ----- Original Message ----- From: "paul swed" To: "Discussion of precise time and frequency measurement" Sent: Thursday, November 12, 2009 3:33 PM Subject: Re: [time-nuts] Rubidium standard > Glenn, > I believe thats the case. > I have a number of the small x cel tower rbs. > You can nurse them a bit. > But the failures I have run into are other things. > Like the tuning cap on the lamp exciter getting noisy > Also I have found re-peaking the multiplier chain can help > It definitely stretches the life a bit. > I would bet things like bypass caps fit into the failures also. > 10 years is a long time for these itty bitty electrolytic s. No reserve > like > the older ones. > Plus they are just fun to play with to try to recover them. > I see date codes like 94-03 on the stuff that I get. So they are long in > the > tooth as it is. > Now the old HP5065 1985 still is going strong. > Believe thats because there simply is more of everything. Gas caps... > Built > like a tank. > regards > > > On Thu, Nov 12, 2009 at 12:40 AM, Glenn Little WB4UIV < > glennmaillist at bellsouth.net> wrote: > >> I was told by a Technical Support Engineer from Symmetricom Global >> Services >> that >> "The typical life span is ~10 years for these Rubidium Time Bases". >> >> This is in response to my request for information on a Ball/Efratom >> PTB-100. >> >> Is this a typical life span of a rubidium standard? >> >> Do some standards last longer than others? >> >> What are the symptoms of a failing rubidium bulb? >> >> Thanks >> 73 >> Glenn >> WB4UIV >> >> >> >> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From ed_palmer at sasktel.net Thu Nov 12 17:29:31 2009 From: ed_palmer at sasktel.net (Ed Palmer) Date: Thu, 12 Nov 2009 11:29:31 -0600 Subject: [time-nuts] Rubidium standard In-Reply-To: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> References: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> Message-ID: <4AFC45FB.9050509@sasktel.net> I've been a Time Nut for a couple of years. During that time I've repaired a couple of dead Efratom FRK Rubidium standards. Both were 20+ years old. One had a dead transistor and the crystal oscillator in the other had drifted so far that it couldn't lock. Both problems were easy to fix. Other than that type of general electronic failures the most likely failure seems to be the Rb lamp itself. It gradually degrades and eventually the lock fails. One of my FRK units is actually below spec for the lamp, but it is still locking okay. Ed Glenn Little WB4UIV wrote: > I was told by a Technical Support Engineer from Symmetricom Global > Services that > "The typical life span is ~10 years for these Rubidium Time Bases". > > This is in response to my request for information on a Ball/Efratom > PTB-100. > > Is this a typical life span of a rubidium standard? > > Do some standards last longer than others? > > What are the symptoms of a failing rubidium bulb? > > Thanks > 73 > Glenn > WB4UIV > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From cdelect at juno.com Thu Nov 12 18:10:45 2009 From: cdelect at juno.com (Corby Dawson) Date: Thu, 12 Nov 2009 10:10:45 -0800 Subject: [time-nuts] Rubidium standard life Message-ID: <20091112.101045.980.2.cdelect@juno.com> Glenn, The lamp is usually the limiting factor. The PRS10 advertises its lamp life to be 20 years. HP bulbs last a bit longer. Tracor bulbs fail with a different mechanism and last maybe 10 years. Efratom bulbs last at least 10 to 15 years. The rejuvenation you referred to is for lamps that have been off for years in uncontrolled temperature environments. These bulbs are not bad, the rubidium has just migrated to the wrong part of the bulb. With a little effort it can be coaxed back where it belongs. A really bad bulb can not be rejuvenated as the rubidium has been absorbed into the inner lining of the bulb envelop. Sometimes these bad bulbs show a definite envelope darkening to the eye. Hope this helps. Corby Dawson ____________________________________________________________ Weight Loss Program Best Weight Loss Program - Click Here! http://thirdpartyoffers.juno.com/TGL2141/c?cp=ygmIjGWNVrMuiulYLVp-bQAAJ1ABLZFyqoH-WnHH1GJ345whAAYAAAAAAAAAAAAAAAAAAADNAAAAAAAAAAAAAAAAAAAEUgAAAAA= From w1ksz at earthlink.net Thu Nov 12 18:20:41 2009 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Thu, 12 Nov 2009 11:20:41 -0700 (GMT-07:00) Subject: [time-nuts] 10 MHz Distribution Amp Message-ID: <27811417.1258050041782.JavaMail.root@mswamui-swiss.atl.sa.earthlink.net> A friend of mine is looking for an inexpensive way to distribute his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while very nice, is a tad on the pricey side when you add in the enclosure. Any ideas what he could use that is not so expensive ? Thanks, Dick, W1KSZ From w6te at msn.com Thu Nov 12 18:32:11 2009 From: w6te at msn.com (David Smith) Date: Thu, 12 Nov 2009 10:32:11 -0800 Subject: [time-nuts] 10 MHz Distribution Amp In-Reply-To: <27811417.1258050041782.JavaMail.root@mswamui-swiss.atl.sa.earthlink.net> References: <27811417.1258050041782.JavaMail.root@mswamui-swiss.atl.sa.earthlink.net> Message-ID: Hi Dick, Down East Microwave makes a 10 MHz distribution kit called the 10-4. I think it sell around $50. 1 input port and 4 output ports. Dave W6TE ----- Original Message ----- From: Richard W. Solomon To: time-nuts at febo.com Sent: Thursday, November 12, 2009 10:20 AM Subject: [time-nuts] 10 MHz Distribution Amp A friend of mine is looking for an inexpensive way to distribute his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while very nice, is a tad on the pricey side when you add in the enclosure. Any ideas what he could use that is not so expensive ? Thanks, Dick, W1KSZ _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From robert8rpi at yahoo.co.uk Thu Nov 12 20:34:58 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Thu, 12 Nov 2009 20:34:58 +0000 (GMT) Subject: [time-nuts] 10 MHz Distribution Amp In-Reply-To: <27811417.1258050041782.JavaMail.root@mswamui-swiss.atl.sa.earthlink.net> Message-ID: <351043.87813.qm@web27105.mail.ukl.yahoo.com> Hi, The cheap alternative is to use a video distribution amp. Even the cheap ones are reasonable. VGA distribution units can also be used, you get three channels. ? Robert G8RPI. --- On Thu, 12/11/09, Richard W. Solomon wrote: From: Richard W. Solomon Subject: [time-nuts] 10 MHz Distribution Amp To: time-nuts at febo.com Date: Thursday, 12 November, 2009, 18:20 A friend of mine is looking for an inexpensive way to distribute his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while very nice, is a tad on the pricey side when you add in the enclosure. Any ideas what he could use that is not so expensive ? Thanks, Dick, W1KSZ _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From EWKehren at aol.com Thu Nov 12 20:45:35 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Thu, 12 Nov 2009 15:45:35 EST Subject: [time-nuts] 10 MHz Distribution Amp Message-ID: Take a look at the LT 6551 it makes a good four channel distribution amp. Bert Kehren In a message dated 11/12/2009 3:36:04 P.M. Eastern Standard Time, robert8rpi at yahoo.co.uk writes: Hi, The cheap alternative is to use a video distribution amp. Even the cheap ones are reasonable. VGA distribution units can also be used, you get three channels. Robert G8RPI. --- On Thu, 12/11/09, Richard W. Solomon wrote: From: Richard W. Solomon Subject: [time-nuts] 10 MHz Distribution Amp To: time-nuts at febo.com Date: Thursday, 12 November, 2009, 18:20 A friend of mine is looking for an inexpensive way to distribute his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while very nice, is a tad on the pricey side when you add in the enclosure. Any ideas what he could use that is not so expensive ? Thanks, Dick, W1KSZ _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From jmiles at pop.net Thu Nov 12 20:54:46 2009 From: jmiles at pop.net (John Miles) Date: Thu, 12 Nov 2009 12:54:46 -0800 Subject: [time-nuts] 10 MHz Distribution Amp In-Reply-To: <351043.87813.qm@web27105.mail.ukl.yahoo.com> Message-ID: Well, the *cheap* alternative is a simple CATV splitter, available off the rack at Home Depot for $5-$10. If you have enough 10 MHz drive, and if your instruments will lock up reliably with the resulting attenuated output, then you're all set. Before I bought a 5087A, I was able to lock almost all of my HP and Tek gear on a 4-port splitter fed by a Thunderbolt at +9 dBm. The only exception was my 5345A counter, but a $2 MAV-11 amplifier took care of that. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of Robert Atkinson > Sent: Thursday, November 12, 2009 12:35 PM > To: Richard W. Solomon; Discussion of precise time and frequency > measurement > Subject: Re: [time-nuts] 10 MHz Distribution Amp > > > Hi, > The cheap alternative is to use a video distribution amp. Even > the cheap ones are reasonable. VGA distribution units can also be > used, you get three channels. > ? > Robert G8RPI. > > --- On Thu, 12/11/09, Richard W. Solomon wrote: > > > From: Richard W. Solomon > Subject: [time-nuts] 10 MHz Distribution Amp > To: time-nuts at febo.com > Date: Thursday, 12 November, 2009, 18:20 > > > A friend of mine is looking for an inexpensive way to distribute > his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while > very nice, is a tad on the pricey side when you add in the enclosure. > > Any ideas what he could use that is not so expensive ? > > Thanks, Dick, W1KSZ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From paulswedb at gmail.com Thu Nov 12 22:29:33 2009 From: paulswedb at gmail.com (paul swed) Date: Thu, 12 Nov 2009 17:29:33 -0500 Subject: [time-nuts] 10 MHz Distribution Amp In-Reply-To: <27811417.1258050041782.JavaMail.root@mswamui-swiss.atl.sa.earthlink.net> References: <27811417.1258050041782.JavaMail.root@mswamui-swiss.atl.sa.earthlink.net> Message-ID: I guess I like simple stupid and common. If the parts are at radio shack... thats indeed common. I use a IRF510 fet $1.99 at RS. Bias it into the linear region and then use a passive R splitter. Roughly 10K to Vdd Doesn't get much easier then that. I also will put a tank circuit on the drain and tune it if I want to make a square wave into a sine wave. Use caps to isolate dc... By the way I do also use Grassvalley video DAs and other broadcast DAs with the clamping turned off. They easily go to 10 MC. But they draw a bit of power compared to the simple fet approach. Regards Paul On Thu, Nov 12, 2009 at 1:20 PM, Richard W. Solomon wrote: > A friend of mine is looking for an inexpensive way to distribute > his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while > very nice, is a tad on the pricey side when you add in the enclosure. > > Any ideas what he could use that is not so expensive ? > > Thanks, Dick, W1KSZ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From w1ksz at earthlink.net Thu Nov 12 22:55:07 2009 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Thu, 12 Nov 2009 15:55:07 -0700 (GMT-07:00) Subject: [time-nuts] 10 MHz Distribution Amp Message-ID: <661637.1258066507753.JavaMail.root@elwamui-hound.atl.sa.earthlink.net> I found something he can use. Thanks to all who replied. 73, Dick, W1KSZ -----Original Message----- From: paul swed Sent: Nov 12, 2009 3:29 PM To: "Richard W. Solomon" , Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 10 MHz Distribution Amp I guess I like simple stupid and common. If the parts are at radio shack... thats indeed common. I use a IRF510 fet $1.99 at RS. Bias it into the linear region and then use a passive R splitter. Roughly 10K to Vdd Doesn't get much easier then that. I also will put a tank circuit on the drain and tune it if I want to make a square wave into a sine wave. Use caps to isolate dc... By the way I do also use Grassvalley video DAs and other broadcast DAs with the clamping turned off. They easily go to 10 MC. But they draw a bit of power compared to the simple fet approach. Regards Paul On Thu, Nov 12, 2009 at 1:20 PM, Richard W. Solomon <[1]w1ksz at earthlink.net> wrote: A friend of mine is looking for an inexpensive way to distribute his 10 MHz T-Bolt signal to other instruments. The TAPR unit, while very nice, is a tad on the pricey side when you add in the enclosure. Any ideas what he could use that is not so expensive ? Thanks, Dick, W1KSZ _______________________________________________ time-nuts mailing list -- [2]time-nuts at febo.com To unsubscribe, go to [3]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. References 1. mailto:w1ksz at earthlink.net 2. mailto:time-nuts at febo.com 3. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts From alfredorosati at alice.it Fri Nov 13 00:09:53 2009 From: alfredorosati at alice.it (Dott. Alfredo Rosati) Date: Fri, 13 Nov 2009 01:09:53 +0100 Subject: [time-nuts] trimble thunderbolt drove LPRO-101 Message-ID: <4AFCA3D1.5070808@alice.it> I tried to drive my lpro with z3805 , but the result was bad. After one hear of testing my thunderbolt , i decided to remove the vtcxo and dive the rubidium LPRO. Is only two days , seems work fine , before i need to trim in frequency my rubidium all week . now should no more need to realign. to mantain precision. Someone had experience ? i5uxj kj6r From glennmaillist at bellsouth.net Fri Nov 13 05:59:55 2009 From: glennmaillist at bellsouth.net (Glenn Little WB4UIV) Date: Fri, 13 Nov 2009 00:59:55 -0500 Subject: [time-nuts] Setting Oscillator Frequency Message-ID: <6.2.3.4.2.20091113005314.05b53d20@mail.bellsouth.net> I just got a system that allows me to compare the phase difference between a reference and an external oscillator. I am using a Vectron oscillator installed in a HP 5345A counter as the external oscillator and a PTB-100 as the reference. How close to the reference should I be able to set the OCXO? After a 3 day warm up, it appears that I have gotten the OCXO to within 0.0025 Hz of the Rubidium reference. I am checking with a strip chart recorder over a three hour period for the next few days to see if the OCXO stays at this accuracy. Is it really possible to set an OCXO this close or have I made some errors in my computation of frequency offset? Thanks 73 Glenn WB4UIV From glennmaillist at bellsouth.net Fri Nov 13 06:13:23 2009 From: glennmaillist at bellsouth.net (Glenn Little WB4UIV) Date: Fri, 13 Nov 2009 01:13:23 -0500 Subject: [time-nuts] Reference oscillator accuracy Message-ID: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> While I was in the US Navy we had two Cesium standards for the navigation center on SSBN submarines. While in port, we would track LORAN C and compute the drift rate of the two cesium standards. Is there a service, that has drift rates published, that I can compare my standards to, so that I can determine the standard drift rate. I do not remember the drift rates that we determined on the submarine, that was a few years ago, but, I seem to remember that the rate was in the low nanoseconds. If a rubidium standard drifts in one direction (does it?) a drift rate could be calculated and, after a comparison to a known standard, with known drift rate, a very accurate standard could be had for the lab. What would I expect the drift rate, or jitter, to be in a FRK class rubidium oscillator? Is the drift rate constant enough that a drift rate could be applied to a rubidium oscillator to determine it's real frequency at any given time. We calibrated the submarine Cesium standards every three months. We had to know the drift rate of our standard as well as the drift rate of the standard in each of the LORAN stations to be able to do the type of LORAN navigation that we did. I would like to be able to verify that my PTB-100 rubidium oscillator is on frequency. If I compare two rubidium oscillators, what would I expect the relative drift rate to be? Thanks 73 Glenn WB4UIV From jgray at zianet.com Fri Nov 13 08:00:30 2009 From: jgray at zianet.com (Joseph Gray) Date: Fri, 13 Nov 2009 01:00:30 -0700 Subject: [time-nuts] Didier Juges Message-ID: I just wanted to publically say thanks to Didier for hosting all of those manuals. I just found yet another manual that I needed. Joe Gray KA5ZEC From w7cs at theriver.com Fri Nov 13 09:03:46 2009 From: w7cs at theriver.com (Chuck Smallhouse) Date: Fri, 13 Nov 2009 02:03:46 -0700 Subject: [time-nuts] 10 MHz Distribution Amplifier Message-ID: <20091113010348.CAF7F227@sj1-dm101.mta.everyone.net> Down East Microwave Inc now has a four channel 10 MHz distribution amplifier with some gain and LP filters on each output. Their price with the PC board and all components, but without connectors and enclosure is about $25 Chuck, W7CS From w6te at msn.com Fri Nov 13 09:16:03 2009 From: w6te at msn.com (David Smith) Date: Fri, 13 Nov 2009 01:16:03 -0800 Subject: [time-nuts] 10 MHz Distribution Amplifier In-Reply-To: <20091113010348.CAF7F227@sj1-dm101.mta.everyone.net> References: <20091113010348.CAF7F227@sj1-dm101.mta.everyone.net> Message-ID: Hi Chuck, Great to see you here. I just joined this GREAT group a few days ago, You may not remember me. I'm Dave W6TE ex WA6YDI. You were one of my first contacts on 2M EME back in the early 80's. You were up in the Bay area and I was in Fresno. I'll never forget the contact because (you were one of my first and) I was hearing you on two paths; the terrestrial path as well as 2.5 seconds later the EME path. I think that was the year that Michael Owen and group activated the big Ontario dish VE3ONT. I hope things are well with you and your wife. Please take care and stay in touch 73, Dave W6TE w6te at msn.com ----- Original Message ----- From: Chuck Smallhouse To: time-nuts at febo.com Sent: Friday, November 13, 2009 1:03 AM Subject: [time-nuts] 10 MHz Distribution Amplifier Down East Microwave Inc now has a four channel 10 MHz distribution amplifier with some gain and LP filters on each output. Their price with the PC board and all components, but without connectors and enclosure is about $25 Chuck, W7CS _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From jltran at worldnet.att.net Fri Nov 13 12:29:31 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Fri, 13 Nov 2009 06:29:31 -0600 Subject: [time-nuts] Didier Juges In-Reply-To: Message-ID: <929C8F23F1B448E98F9EBD8E32573118@S0028384766> An amazing resource!!!!!!!! Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Joseph Gray Sent: Friday, November 13, 2009 2:01 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Didier Juges I just wanted to publically say thanks to Didier for hosting all of those manuals. I just found yet another manual that I needed. Joe Gray KA5ZEC _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From didier at cox.net Fri Nov 13 13:08:47 2009 From: didier at cox.net (Didier Juges) Date: Fri, 13 Nov 2009 07:08:47 -0600 Subject: [time-nuts] Didier Juges In-Reply-To: <929C8F23F1B448E98F9EBD8E32573118@S0028384766> References: <929C8F23F1B448E98F9EBD8E32573118@S0028384766> Message-ID: <698AAFEED442442DA44D3FAD8875C29A@d400> Thanks to everybody's help, it just keeps growing and growing :) 18,903 files as of today. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of J. L. Trantham > Sent: Friday, November 13, 2009 6:30 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Didier Juges > > An amazing resource!!!!!!!! > > Joe > > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Joseph Gray > Sent: Friday, November 13, 2009 2:01 AM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Didier Juges > > > I just wanted to publically say thanks to Didier for hosting > all of those manuals. I just found yet another manual that I needed. > > Joe Gray > KA5ZEC > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jltran at worldnet.att.net Fri Nov 13 13:23:29 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Fri, 13 Nov 2009 07:23:29 -0600 Subject: [time-nuts] Didier Juges In-Reply-To: <698AAFEED442442DA44D3FAD8875C29A@d400> Message-ID: The website is an amazing resource, too! ;>) Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Didier Juges Sent: Friday, November 13, 2009 7:09 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Didier Juges Thanks to everybody's help, it just keeps growing and growing :) 18,903 files as of today. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of J. L. Trantham > Sent: Friday, November 13, 2009 6:30 AM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Didier Juges > > An amazing resource!!!!!!!! > > Joe > > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Joseph Gray > Sent: Friday, November 13, 2009 2:01 AM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Didier Juges > > > I just wanted to publically say thanks to Didier for hosting > all of those manuals. I just found yet another manual that I needed. > > Joe Gray > KA5ZEC > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From bob.raker at gmail.com Fri Nov 13 17:45:18 2009 From: bob.raker at gmail.com (Bob Raker) Date: Fri, 13 Nov 2009 12:45:18 -0500 Subject: [time-nuts] Setting Oscillator Frequency In-Reply-To: <6.2.3.4.2.20091113005314.05b53d20@mail.bellsouth.net> References: <6.2.3.4.2.20091113005314.05b53d20@mail.bellsouth.net> Message-ID: Glenn, From kilodelta4foxmike at gmail.com Fri Nov 13 17:48:19 2009 From: kilodelta4foxmike at gmail.com (Brian Kirby) Date: Fri, 13 Nov 2009 11:48:19 -0600 Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> Message-ID: <4AFD9BE3.8020007@gmail.com> You will need a receiver to compare your references to. It appears that LORAN will be shut off, so that leaves two services available, either WWV 60 Khz or GPS. I do not use WWV any more, I can tell you about GPS. To compare against GPS you will need a timing receiver, there are several available. A lot of us got Motorola Oncore VPs, UTs, or M12+, The Rockwell Jupiter is one and there are several more. They provide a 1 PPS signal that is locked to the on board standards on the GPS satellite. You put this signal in one input of a time interval counter. You use a 1 PPS divider on your local reference and put its signal in the other input of the time interval counter. You can record continuous or take daily 24 hour readings and derive your drift rates. GPS corrections are published at NIST; http://tf.nist.gov/service/gpstrace.htm You can also compare against a GPS disciplined oscillator. In the long term it should be dead on, you will have to have it characterized for the short term. The HP Z3801A was on the surplus market several years back, its probably one of the best. The Trimble Thunderbolts were available to the group a while back. Brian KD4FM Glenn Little WB4UIV wrote: > While I was in the US Navy we had two Cesium standards for the > navigation center on SSBN submarines. > While in port, we would track LORAN C and compute the drift rate of > the two cesium standards. > Is there a service, that has drift rates published, that I can compare > my standards to, so that I can determine the standard drift rate. > I do not remember the drift rates that we determined on the submarine, > that was a few years ago, but, I seem to remember that the rate was in > the low nanoseconds. > If a rubidium standard drifts in one direction (does it?) a drift rate > could be calculated and, after a comparison to a known standard, with > known drift rate, a very accurate standard could be had for the lab. > > What would I expect the drift rate, or jitter, to be in a FRK class > rubidium oscillator? > > Is the drift rate constant enough that a drift rate could be applied > to a rubidium oscillator to determine it's real frequency at any given > time. > > We calibrated the submarine Cesium standards every three months. > We had to know the drift rate of our standard as well as the drift > rate of the standard in each of the LORAN stations to be able to do > the type of LORAN navigation that we did. > > I would like to be able to verify that my PTB-100 rubidium oscillator > is on frequency. > > If I compare two rubidium oscillators, what would I expect the > relative drift rate to be? > > Thanks > 73 > Glenn > WB4UIV > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jfor at quik.com Fri Nov 13 17:51:11 2009 From: jfor at quik.com (J. Forster) Date: Fri, 13 Nov 2009 09:51:11 -0800 (PST) Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <4AFD9BE3.8020007@gmail.com> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> Message-ID: <1529.12.6.201.202.1258134671.squirrel@popacctsnew.quik.com> WWVB not WWV. IMO, WWVB is MUCH fussier than LORAN. It's just utter stupidity that LORAN is being shut down. -John ============ > You will need a receiver to compare your references to. It appears that > LORAN will be shut off, so that leaves two services available, either > WWV 60 Khz or GPS. I do not use WWV any more, I can tell you about GPS. > > To compare against GPS you will need a timing receiver, there are > several available. A lot of us got Motorola Oncore VPs, UTs, or M12+, > The Rockwell Jupiter is one and there are several more. They provide a > 1 PPS signal that is locked to the on board standards on the GPS > satellite. You put this signal in one input of a time interval > counter. You use a 1 PPS divider on your local reference and put its > signal in the other input of the time interval counter. You can record > continuous or take daily 24 hour readings and derive your drift rates. > > GPS corrections are published at NIST; > http://tf.nist.gov/service/gpstrace.htm > > You can also compare against a GPS disciplined oscillator. In the long > term it should be dead on, you will have to have it characterized for > the short term. The HP Z3801A was on the surplus market several years > back, its probably one of the best. The Trimble Thunderbolts were > available to the group a while back. > > Brian KD4FM > > Glenn Little WB4UIV wrote: >> While I was in the US Navy we had two Cesium standards for the >> navigation center on SSBN submarines. >> While in port, we would track LORAN C and compute the drift rate of >> the two cesium standards. >> Is there a service, that has drift rates published, that I can compare >> my standards to, so that I can determine the standard drift rate. >> I do not remember the drift rates that we determined on the submarine, >> that was a few years ago, but, I seem to remember that the rate was in >> the low nanoseconds. >> If a rubidium standard drifts in one direction (does it?) a drift rate >> could be calculated and, after a comparison to a known standard, with >> known drift rate, a very accurate standard could be had for the lab. >> >> What would I expect the drift rate, or jitter, to be in a FRK class >> rubidium oscillator? >> >> Is the drift rate constant enough that a drift rate could be applied >> to a rubidium oscillator to determine it's real frequency at any given >> time. >> >> We calibrated the submarine Cesium standards every three months. >> We had to know the drift rate of our standard as well as the drift >> rate of the standard in each of the LORAN stations to be able to do >> the type of LORAN navigation that we did. >> >> I would like to be able to verify that my PTB-100 rubidium oscillator >> is on frequency. >> >> If I compare two rubidium oscillators, what would I expect the >> relative drift rate to be? >> >> Thanks >> 73 >> Glenn >> WB4UIV >> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From paulswedb at gmail.com Fri Nov 13 18:08:52 2009 From: paulswedb at gmail.com (paul swed) Date: Fri, 13 Nov 2009 13:08:52 -0500 Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <4AFD9BE3.8020007@gmail.com> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> Message-ID: I use GPS and LORAN. Always nice to have a backup With LORAN being shut down, have resurrected the ole wwvb rcvr and built an amplified loop ant. Can work but it takes about 3-5 hours to get to 1X10^11 accuracy. Still observing various strange ness shuch as diurnal shift ... Odd wwvb works at least for me most stable in the day. I seem to remember night was supposed to be better. The signal is much stronger at night. So I guess its a play but sure not as easy as gud ole LORAN C has been. On Fri, Nov 13, 2009 at 12:48 PM, Brian Kirby wrote: > You will need a receiver to compare your references to. It appears that > LORAN will be shut off, so that leaves two services available, either WWV 60 > Khz or GPS. I do not use WWV any more, I can tell you about GPS. > > To compare against GPS you will need a timing receiver, there are several > available. A lot of us got Motorola Oncore VPs, UTs, or M12+, The Rockwell > Jupiter is one and there are several more. They provide a 1 PPS signal that > is locked to the on board standards on the GPS satellite. You put this > signal in one input of a time interval counter. You use a 1 PPS divider on > your local reference and put its signal in the other input of the time > interval counter. You can record continuous or take daily 24 hour readings > and derive your drift rates. > > GPS corrections are published at NIST; > http://tf.nist.gov/service/gpstrace.htm > > You can also compare against a GPS disciplined oscillator. In the long > term it should be dead on, you will have to have it characterized for the > short term. The HP Z3801A was on the surplus market several years back, its > probably one of the best. The Trimble Thunderbolts were available to the > group a while back. > Brian KD4FM > > > Glenn Little WB4UIV wrote: > >> While I was in the US Navy we had two Cesium standards for the navigation >> center on SSBN submarines. >> While in port, we would track LORAN C and compute the drift rate of the >> two cesium standards. >> Is there a service, that has drift rates published, that I can compare my >> standards to, so that I can determine the standard drift rate. >> I do not remember the drift rates that we determined on the submarine, >> that was a few years ago, but, I seem to remember that the rate was in the >> low nanoseconds. >> If a rubidium standard drifts in one direction (does it?) a drift rate >> could be calculated and, after a comparison to a known standard, with known >> drift rate, a very accurate standard could be had for the lab. >> >> What would I expect the drift rate, or jitter, to be in a FRK class >> rubidium oscillator? >> >> Is the drift rate constant enough that a drift rate could be applied to a >> rubidium oscillator to determine it's real frequency at any given time. >> >> We calibrated the submarine Cesium standards every three months. >> We had to know the drift rate of our standard as well as the drift rate of >> the standard in each of the LORAN stations to be able to do the type of >> LORAN navigation that we did. >> >> I would like to be able to verify that my PTB-100 rubidium oscillator is >> on frequency. >> >> If I compare two rubidium oscillators, what would I expect the relative >> drift rate to be? >> >> Thanks >> 73 >> Glenn >> WB4UIV >> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From paulswedb at gmail.com Fri Nov 13 18:10:59 2009 From: paulswedb at gmail.com (paul swed) Date: Fri, 13 Nov 2009 13:10:59 -0500 Subject: [time-nuts] Didier Juges In-Reply-To: References: Message-ID: Joe boy do I agree with your comments on Didiers site. Been very very helpful. Thank you Didier and everyone who has contributed. On Fri, Nov 13, 2009 at 3:00 AM, Joseph Gray wrote: > I just wanted to publically say thanks to Didier for hosting all of > those manuals. I just found yet another manual that I needed. > > Joe Gray > KA5ZEC > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From djl at montana.com Fri Nov 13 18:15:04 2009 From: djl at montana.com (Don Latham) Date: Fri, 13 Nov 2009 11:15:04 -0700 (MST) Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> Message-ID: <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com> The ground wave path of WWVB varies due to a very small changes in the index of refraction (temperature and absolute humidity) over the path. It is not much, but is measurable. Don paul swed > I use GPS and LORAN. Always nice to have a backup > With LORAN being shut down, have resurrected the ole wwvb rcvr and built > an > amplified loop ant. > Can work but it takes about 3-5 hours to get to 1X10^11 accuracy. Still > observing various strange ness shuch as diurnal shift ... > Odd wwvb works at least for me most stable in the day. I seem to remember > night was supposed to be better. > The signal is much stronger at night. > So I guess its a play but sure not as easy as gud ole LORAN C has been. > > On Fri, Nov 13, 2009 at 12:48 PM, Brian Kirby > wrote: > >> You will need a receiver to compare your references to. It appears that >> LORAN will be shut off, so that leaves two services available, either >> WWV 60 >> Khz or GPS. I do not use WWV any more, I can tell you about GPS. >> >> To compare against GPS you will need a timing receiver, there are >> several >> available. A lot of us got Motorola Oncore VPs, UTs, or M12+, The >> Rockwell >> Jupiter is one and there are several more. They provide a 1 PPS signal >> that >> is locked to the on board standards on the GPS satellite. You put this >> signal in one input of a time interval counter. You use a 1 PPS divider >> on >> your local reference and put its signal in the other input of the time >> interval counter. You can record continuous or take daily 24 hour >> readings >> and derive your drift rates. >> >> GPS corrections are published at NIST; >> http://tf.nist.gov/service/gpstrace.htm >> >> You can also compare against a GPS disciplined oscillator. In the long >> term it should be dead on, you will have to have it characterized for >> the >> short term. The HP Z3801A was on the surplus market several years back, >> its >> probably one of the best. The Trimble Thunderbolts were available to >> the >> group a while back. >> Brian KD4FM >> >> >> Glenn Little WB4UIV wrote: >> >>> While I was in the US Navy we had two Cesium standards for the >>> navigation >>> center on SSBN submarines. >>> While in port, we would track LORAN C and compute the drift rate of the >>> two cesium standards. >>> Is there a service, that has drift rates published, that I can compare >>> my >>> standards to, so that I can determine the standard drift rate. >>> I do not remember the drift rates that we determined on the submarine, >>> that was a few years ago, but, I seem to remember that the rate was in >>> the >>> low nanoseconds. >>> If a rubidium standard drifts in one direction (does it?) a drift rate >>> could be calculated and, after a comparison to a known standard, with >>> known >>> drift rate, a very accurate standard could be had for the lab. >>> >>> What would I expect the drift rate, or jitter, to be in a FRK class >>> rubidium oscillator? >>> >>> Is the drift rate constant enough that a drift rate could be applied to >>> a >>> rubidium oscillator to determine it's real frequency at any given time. >>> >>> We calibrated the submarine Cesium standards every three months. >>> We had to know the drift rate of our standard as well as the drift rate >>> of >>> the standard in each of the LORAN stations to be able to do the type of >>> LORAN navigation that we did. >>> >>> I would like to be able to verify that my PTB-100 rubidium oscillator >>> is >>> on frequency. >>> >>> If I compare two rubidium oscillators, what would I expect the relative >>> drift rate to be? >>> >>> Thanks >>> 73 >>> Glenn >>> WB4UIV >>> >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From hmurray at megapathdsl.net Fri Nov 13 18:30:51 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Fri, 13 Nov 2009 10:30:51 -0800 Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: Message from "Don Latham" of "Fri, 13 Nov 2009 11:15:04 MST." <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com> Message-ID: <20091113183052.72132BCFC@ip-64-139-1-69.sjc.megapath.net> > The ground wave path of WWVB varies due to a very small changes in the > index of refraction (temperature and absolute humidity) over the path. > It is not much, but is measurable. How much is "not much"? Say over a 1000 km path. Are we talking microseconds or picoseconds? -- These are my opinions, not necessarily my employer's. I hate spam. From time-nuts at kasperkp.dk Fri Nov 13 18:32:31 2009 From: time-nuts at kasperkp.dk (Kasper Pedersen) Date: Fri, 13 Nov 2009 19:32:31 +0100 Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com> Message-ID: <4AFDA63F.5040105@kasperkp.dk> On 11/13/2009 07:15 PM, Don Latham wrote: > The ground wave path of WWVB varies due to a very small changes in the > index of refraction (temperature and absolute humidity) over the path. It > is not much, but is measurable. > Don > My own nuttiness started with that, and the innocent question "How much? What does it take to measure it? What do I need to build?" http://n1.taur.dk/dcf/ (raw data and plots, time is UTC+1) I am no more than 6-700 km north of DCF77, and get ~5us p-p. Now that is quite large, when I started out that number seemed a lot smaller. /Kasper Pedersen From jfor at quik.com Fri Nov 13 18:52:51 2009 From: jfor at quik.com (J. Forster) Date: Fri, 13 Nov 2009 10:52:51 -0800 (PST) Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <20091113183052.72132BCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091113183052.72132BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <1676.12.6.201.202.1258138371.squirrel@popacctsnew.quik.com> It's been a while since I was using an HP 117A, but from memory the diurnal shift in Boston was a good part of a 1 cycle of 60 KHz or roughly 16 uS. To get good data, I'd have to run the stripchart for 24 hours (to make sure track was not lost) and compsare readings at the same time each day. LORAN was MUCH easier. FWIW, -John ================= > >> The ground wave path of WWVB varies due to a very small changes in the >> index of refraction (temperature and absolute humidity) over the path. >> It is not much, but is measurable. > > How much is "not much"? Say over a 1000 km path. Are we talking > microseconds or picoseconds? > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From djl at montana.com Fri Nov 13 22:01:47 2009 From: djl at montana.com (Don Latham) Date: Fri, 13 Nov 2009 15:01:47 -0700 Subject: [time-nuts] Reference oscillator accuracy References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com> <4AFDA63F.5040105@kasperkp.dk> Message-ID: <94E812E8F29641488680719656A4E639@OFFICE2> Hi All: I've copied my paper "Diurnal frequency variation and refractive index" from Nature Physical Sciences, Vol. 234, 51, pp. 157-158, Dec. 20, 1971. There are two TIFF files (I tried like heck to get them in one file, and failed miserably, cannot understand my image software worth a #$%^. The way to calculate the refractive index of moist air is given. I don't know how to post these images to the list, so help please. There was no reason to pursue the idea at the time, so maybe with the extensive network of the time-nuts some sense can be made of the idea. Dunno. Don Latham ----- Original Message ----- From: "Kasper Pedersen" To: Sent: Friday, November 13, 2009 11:32 AM Subject: Re: [time-nuts] Reference oscillator accuracy > On 11/13/2009 07:15 PM, Don Latham wrote: >> The ground wave path of WWVB varies due to a very small changes in the >> index of refraction (temperature and absolute humidity) over the path. It >> is not much, but is measurable. >> Don >> > > My own nuttiness started with that, and the innocent question "How much? > What does it take to measure it? What do I need to build?" > > http://n1.taur.dk/dcf/ (raw data and plots, time is UTC+1) > > I am no more than 6-700 km north of DCF77, and get ~5us p-p. Now that is > quite large, when I started out that number seemed a lot smaller. > > /Kasper Pedersen > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From didier at cox.net Fri Nov 13 22:51:48 2009 From: didier at cox.net (Didier Juges) Date: Fri, 13 Nov 2009 22:51:48 +0000 Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <94E812E8F29641488680719656A4E639@OFFICE2> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com><4AFDA63F.5040105@kasperkp.dk><94E812E8F29641488680719656A4E639@OFFICE2> Message-ID: <662624584-1258152708-cardhu_decombobulator_blackberry.rim.net-1937352721-@bda224.bisx.prod.on.blackberry> Don, you are welcome to upload your pictures (and paper) to my web site, where people normally upload manuals. Didier KO4BB http://www.ko4bb.com/cgi-bin/manuals.pl ------------------------ Sent from my BlackBerry Wireless thingy while I do other things... -----Original Message----- From: "Don Latham" Date: Fri, 13 Nov 2009 15:01:47 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Reference oscillator accuracy Hi All: I've copied my paper "Diurnal frequency variation and refractive index" from Nature Physical Sciences, Vol. 234, 51, pp. 157-158, Dec. 20, 1971. There are two TIFF files (I tried like heck to get them in one file, and failed miserably, cannot understand my image software worth a #$%^. The way to calculate the refractive index of moist air is given. I don't know how to post these images to the list, so help please. There was no reason to pursue the idea at the time, so maybe with the extensive network of the time-nuts some sense can be made of the idea. Dunno. Don Latham ----- Original Message ----- From: "Kasper Pedersen" To: Sent: Friday, November 13, 2009 11:32 AM Subject: Re: [time-nuts] Reference oscillator accuracy > On 11/13/2009 07:15 PM, Don Latham wrote: >> The ground wave path of WWVB varies due to a very small changes in the >> index of refraction (temperature and absolute humidity) over the path. It >> is not much, but is measurable. >> Don >> > > My own nuttiness started with that, and the innocent question "How much? > What does it take to measure it? What do I need to build?" > > http://n1.taur.dk/dcf/ (raw data and plots, time is UTC+1) > > I am no more than 6-700 km north of DCF77, and get ~5us p-p. Now that is > quite large, when I started out that number seemed a lot smaller. > > /Kasper Pedersen > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From die at dieconsulting.com Sat Nov 14 02:27:58 2009 From: die at dieconsulting.com (David I. Emery) Date: Fri, 13 Nov 2009 21:27:58 -0500 Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <1529.12.6.201.202.1258134671.squirrel@popacctsnew.quik.com> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> <1529.12.6.201.202.1258134671.squirrel@popacctsnew.quik.com> Message-ID: <20091114022758.GA12555@pig.dieconsulting.com> On Fri, Nov 13, 2009 at 09:51:11AM -0800, J. Forster wrote: > WWVB not WWV. > > IMO, WWVB is MUCH fussier than LORAN. It's just utter stupidity that LORAN > is being shut down. I have emailed my brother in law who is a rear admiral (I think now called a vice admiral) and currently CFO of the USCG (and as a note re your alma mater a MIT Sloan grad) and rather loudly said so myself. He most likely was part of the group that made the decision... I intend to ask him why they did it when I next see him. -- Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." From jfor at quik.com Sat Nov 14 03:01:35 2009 From: jfor at quik.com (J. Forster) Date: Fri, 13 Nov 2009 19:01:35 -0800 (PST) Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <20091114022758.GA12555@pig.dieconsulting.com> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> <1529.12.6.201.202.1258134671.squirrel@popacctsnew.quik.com> <20091114022758.GA12555@pig.dieconsulting.com> Message-ID: <3378.12.6.201.202.1258167695.squirrel@popacctsnew.quik.com> I asked a close friend and fellow engineering alum who was deeply involved in GPS and he thinks closing down LORAN is utterly idiotic. IMO, there is something purely political, rather than technical, about this decision. Perhaps the GPS "stakeholders" don't want to admit just how vulnerable GPS is to jamming (and hence a backup is not needed), just as software vendors don't want to admit security holes or banks want to admit that millions are stolen through computer fraud. FWIW, -John BTW, Sloan is a school of Management, NOT Engineering. There is a VERY big difference. =================== > On Fri, Nov 13, 2009 at 09:51:11AM -0800, J. Forster wrote: >> WWVB not WWV. >> >> IMO, WWVB is MUCH fussier than LORAN. It's just utter stupidity that >> LORAN >> is being shut down. > > I have emailed my brother in law who is a rear admiral (I think > now called a vice admiral) and currently CFO of the USCG (and as a note > re your alma mater a MIT Sloan grad) and rather loudly said so myself. > He most likely was part of the group that made the decision... I intend > to ask him why they did it when I next see him. > > > -- > Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass > 02493 > "An empty zombie mind with a forlorn barely readable weatherbeaten > 'For Rent' sign still vainly flapping outside on the weed encrusted pole - > in > celebration of what could have been, but wasn't and is not to be now > either." > > From joegeller at roadrunner.com Sat Nov 14 03:11:26 2009 From: joegeller at roadrunner.com (Joe Geller) Date: Fri, 13 Nov 2009 22:11:26 -0500 Subject: [time-nuts] Loran C shutdown Message-ID: <20091113221126.625193@nectarine> The Coast Guard has always been stretched very thin with limited resources for many missions. The saying was, every year we do more and more with less and less. I served in the late 70s as an electronics technician, EE, and later after Navy flight school, flying air rescue into the 80s. I was lucky to spend some time at two of the research labs, the electronics engineering center (EECEN) in Wildwood, NJ and later the electrical engineering laboratory (EELAB) in Alexandria, VA. At EELAB, I worked in other areas, but a lot of the LORAN work was done there. I remember, even back then, that some of the LORAN guys were searching hobby electronics suppliers to find obsolete chips they needed to keep the LORAN system going. I think those were LORAN C boards too, although not sure. Some new LORAN boards were being developed at the next bench over that used 6502 micros (I got to go to the micro class with the LORAN guys). Flying HU-25A Falcon jets (modified Falcon 200s that we got in 1982) across the Gulf of Mexico for some years, we had a gyro inertial system (which took some 20 minutes to align), LORAN C, and all the standard aviation navigation gear, ADF, VOR, DME, and TACAN. The Collins ?RNAV? system used all inputs to develop position information. As I recall, once we got hundreds of miles out into the gulf, all we had left was the inertial system (and paper charts and aluminum slide rules and later my hp-41CV with nav equations, when the RNAV when out). What we would have given for a GPS! Oh well, at least on the bright side, maybe some of those hp clocks will start to show up on the surplus market. There is a picture of the Falcon at: http://www.aero-web.org/database/aircraft/getimage.htm?id=15047 From jgray at zianet.com Sat Nov 14 07:08:52 2009 From: jgray at zianet.com (Joseph Gray) Date: Sat, 14 Nov 2009 00:08:52 -0700 Subject: [time-nuts] FS: HP 5315A Message-ID: I recently acquired an HP 5315A Universal Counter and no longer have a need for it. As best as I can tell, it works fine. It has a calibration sticker on it dated Feb 2008. I haven't opened it or messed with it at all. Make me an offer off-list, via email. I'll let it go cheap. Joe Gray KA5ZEC From didier at cox.net Sat Nov 14 13:27:57 2009 From: didier at cox.net (Didier Juges) Date: Sat, 14 Nov 2009 07:27:57 -0600 Subject: [time-nuts] Didier Juges In-Reply-To: References: Message-ID: <9BF35C9C56624EF9A918901BBB1DA7D2@d400> Thanks for the good comments :) I am glad to help. Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of paul swed > Sent: Friday, November 13, 2009 12:11 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Didier Juges > > Joe boy do I agree with your comments on Didiers site. > Been very very helpful. > Thank you Didier and everyone who has contributed. > > On Fri, Nov 13, 2009 at 3:00 AM, Joseph Gray wrote: > > > I just wanted to publically say thanks to Didier for hosting all of > > those manuals. I just found yet another manual that I needed. > > > > Joe Gray > > KA5ZEC > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From ch at murgatroid.com Sat Nov 14 20:40:42 2009 From: ch at murgatroid.com (Christopher Hoover) Date: Sat, 14 Nov 2009 12:40:42 -0800 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: Message-ID: <4AFF15CA.1000704@murgatroid.com> David I. Emery wrote: > I have emailed my brother in law who is a rear admiral (I think > now called a vice admiral) and currently CFO of the USCG (and as a note > re your alma mater a MIT Sloan grad) and rather loudly said so myself. > He most likely was part of the group that made the decision... I intend > to ask him why they did it when I next see him. David, I see three possibilities: a) modernization (E-LORAN), b) maintain existing service and capabilities, c) shut it down. It would be helpful to know if USCG supports the plan to shut the system down. If USCG does not, those of us who are US citizens can lobby Congress to restore funding for the service. There's an educational piece here to do. -ch From frledda at verizon.net Sat Nov 14 20:57:31 2009 From: frledda at verizon.net (Francesco Ledda) Date: Sat, 14 Nov 2009 14:57:31 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4AFF15CA.1000704@murgatroid.com> References: <4AFF15CA.1000704@murgatroid.com> Message-ID: AOPA is pushing congress to repristinate funding for LORAN. General aviation is probably the heaviest user on this Nav system. The aviation user community would love to see Nav systems with integrated LORAN and GPS capabilty, but the industry has done little in this area, due to lack of government commitment to LORAN. The FAA knows the GPS can be easily jammed, but has done nothing do push LORAN as the GPS backup system. Sent from my iPhone On Nov 14, 2009, at 2:40 PM, Christopher Hoover wrote: > David I. Emery wrote: >> I have emailed my brother in law who is a rear admiral (I think >> now called a vice admiral) and currently CFO of the USCG (and as a >> note >> re your alma mater a MIT Sloan grad) and rather loudly said so >> myself. He most likely was part of the group that made the >> decision... I intend >> to ask him why they did it when I next see him. > > David, > > I see three possibilities: a) modernization (E-LORAN), b) maintain > existing service and capabilities, c) shut it down. > > It would be helpful to know if USCG supports the plan to shut the > system down. > If USCG does not, those of us who are US citizens can lobby Congress > to restore funding for the service. There's an educational piece > here to do. > > > -ch > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From jfor at quik.com Sat Nov 14 21:26:20 2009 From: jfor at quik.com (J. Forster) Date: Sat, 14 Nov 2009 13:26:20 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4AFF15CA.1000704@murgatroid.com> Message-ID: <2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com> Does anybody know who in Congress might take the lead in reversing the decision? None of the reps in this state are at all likely to give a damn. Their interest is apparently only in social issues. -John ===================== > AOPA is pushing congress to repristinate funding for LORAN. General > aviation is probably the heaviest user on this Nav system. The > aviation user community would love to see Nav systems with integrated > LORAN and GPS capabilty, but the industry has done little in this > area, due to lack of government commitment to LORAN. The FAA knows the > GPS can be easily jammed, but has done nothing do push LORAN as the > GPS backup system. > > Sent from my iPhone > > > On Nov 14, 2009, at 2:40 PM, Christopher Hoover > wrote: > >> David I. Emery wrote: >>> I have emailed my brother in law who is a rear admiral (I think >>> now called a vice admiral) and currently CFO of the USCG (and as a >>> note >>> re your alma mater a MIT Sloan grad) and rather loudly said so >>> myself. He most likely was part of the group that made the >>> decision... I intend >>> to ask him why they did it when I next see him. >> >> David, >> >> I see three possibilities: a) modernization (E-LORAN), b) maintain >> existing service and capabilities, c) shut it down. >> >> It would be helpful to know if USCG supports the plan to shut the >> system down. >> If USCG does not, those of us who are US citizens can lobby Congress >> to restore funding for the service. There's an educational piece >> here to do. >> >> >> -ch >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From djl at montana.com Sat Nov 14 22:05:17 2009 From: djl at montana.com (Don Latham) Date: Sat, 14 Nov 2009 15:05:17 -0700 (MST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com> References: <4AFF15CA.1000704@murgatroid.com> <2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com> Message-ID: <15f4093efb962d5630fc0ec5eb1ed7ab.squirrel@webmail.montana.com> You've hit it on the nose. NONE of them are interested in anything but social issues. LORAN will not get any of them re-elected, and that's all any of 'em care about. Don J. Forster > Does anybody know who in Congress might take the lead in reversing the > decision? None of the reps in this state are at all likely to give a damn. > Their interest is apparently only in social issues. > > -John > > ===================== > >> AOPA is pushing congress to repristinate funding for LORAN. General >> aviation is probably the heaviest user on this Nav system. The >> aviation user community would love to see Nav systems with integrated >> LORAN and GPS capabilty, but the industry has done little in this >> area, due to lack of government commitment to LORAN. The FAA knows the >> GPS can be easily jammed, but has done nothing do push LORAN as the >> GPS backup system. >> >> Sent from my iPhone >> >> >> On Nov 14, 2009, at 2:40 PM, Christopher Hoover >> wrote: >> >>> David I. Emery wrote: >>>> I have emailed my brother in law who is a rear admiral (I think >>>> now called a vice admiral) and currently CFO of the USCG (and as a >>>> note >>>> re your alma mater a MIT Sloan grad) and rather loudly said so >>>> myself. He most likely was part of the group that made the >>>> decision... I intend >>>> to ask him why they did it when I next see him. >>> >>> David, >>> >>> I see three possibilities: a) modernization (E-LORAN), b) maintain >>> existing service and capabilities, c) shut it down. >>> >>> It would be helpful to know if USCG supports the plan to shut the >>> system down. >>> If USCG does not, those of us who are US citizens can lobby Congress >>> to restore funding for the service. There's an educational piece >>> here to do. >>> >>> >>> -ch >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From jfor at quik.com Sat Nov 14 22:35:26 2009 From: jfor at quik.com (J. Forster) Date: Sat, 14 Nov 2009 14:35:26 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <15f4093efb962d5630fc0ec5eb1ed7ab.squirrel@webmail.montana.com> References: <4AFF15CA.1000704@murgatroid.com> <2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com> <15f4093efb962d5630fc0ec5eb1ed7ab.squirrel@webmail.montana.com> Message-ID: <2297.12.6.201.202.1258238126.squirrel@popacctsnew.quik.com> OK, so who is in a position to MAKE them care? How about those who understand this is a Homeland Security (among other) issue? Perhaps FOX news? Likely LORAN costs about as much a year as a mile of fence along the Mexican border, probably less. FWIW, -John ================ > You've hit it on the nose. NONE of them are interested in anything but > social issues. LORAN will not get any of them re-elected, and that's all > any of 'em care about. > Don > > J. Forster >> Does anybody know who in Congress might take the lead in reversing the >> decision? None of the reps in this state are at all likely to give a >> damn. >> Their interest is apparently only in social issues. >> >> -John >> >> ===================== >> >>> AOPA is pushing congress to repristinate funding for LORAN. General >>> aviation is probably the heaviest user on this Nav system. The >>> aviation user community would love to see Nav systems with integrated >>> LORAN and GPS capabilty, but the industry has done little in this >>> area, due to lack of government commitment to LORAN. The FAA knows the >>> GPS can be easily jammed, but has done nothing do push LORAN as the >>> GPS backup system. >>> >>> Sent from my iPhone >>> >>> >>> On Nov 14, 2009, at 2:40 PM, Christopher Hoover >>> wrote: >>> >>>> David I. Emery wrote: >>>>> I have emailed my brother in law who is a rear admiral (I think >>>>> now called a vice admiral) and currently CFO of the USCG (and as a >>>>> note >>>>> re your alma mater a MIT Sloan grad) and rather loudly said so >>>>> myself. He most likely was part of the group that made the >>>>> decision... I intend >>>>> to ask him why they did it when I next see him. >>>> >>>> David, >>>> >>>> I see three possibilities: a) modernization (E-LORAN), b) maintain >>>> existing service and capabilities, c) shut it down. >>>> >>>> It would be helpful to know if USCG supports the plan to shut the >>>> system down. >>>> If USCG does not, those of us who are US citizens can lobby Congress >>>> to restore funding for the service. There's an educational piece >>>> here to do. >>>> >>>> >>>> -ch >>>> >>>> >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > -- > Dr. Don Latham AJ7LL > Six Mile Systems LLP > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > www.lightningforensics.com > www.sixmilesystems.com > > From mccorkle at ptialaska.net Sat Nov 14 23:12:46 2009 From: mccorkle at ptialaska.net (Richard H McCorkle) Date: Sat, 14 Nov 2009 14:12:46 -0900 (AKST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com> References: <4AFF15CA.1000704@murgatroid.com> <2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com> Message-ID: <10543.206.174.20.67.1258240366.squirrel@mymail.acsalaska.net> John, I have asked Alaska's representitives to reinstate LORAN funding due to the large number of private pilots and small fishing boat operators that rely on LORAN in Alaska. During periods of high aurora activity in the arctic the interference with GPS makes it unusable and LORAN is the only viable alternative navigation system. Richard > Does anybody know who in Congress might take the lead in reversing the > decision? None of the reps in this state are at all likely to give a damn. > Their interest is apparently only in social issues. > > -John > > ===================== > >> AOPA is pushing congress to repristinate funding for LORAN. General >> aviation is probably the heaviest user on this Nav system. The >> aviation user community would love to see Nav systems with integrated >> LORAN and GPS capabilty, but the industry has done little in this >> area, due to lack of government commitment to LORAN. The FAA knows the >> GPS can be easily jammed, but has done nothing do push LORAN as the >> GPS backup system. >> >> Sent from my iPhone >> >> >> On Nov 14, 2009, at 2:40 PM, Christopher Hoover >> wrote: >> >>> David I. Emery wrote: >>>> I have emailed my brother in law who is a rear admiral (I think >>>> now called a vice admiral) and currently CFO of the USCG (and as a >>>> note >>>> re your alma mater a MIT Sloan grad) and rather loudly said so >>>> myself. He most likely was part of the group that made the >>>> decision... I intend >>>> to ask him why they did it when I next see him. >>> >>> David, >>> >>> I see three possibilities: a) modernization (E-LORAN), b) maintain >>> existing service and capabilities, c) shut it down. >>> >>> It would be helpful to know if USCG supports the plan to shut the >>> system down. >>> If USCG does not, those of us who are US citizens can lobby Congress >>> to restore funding for the service. There's an educational piece >>> here to do. >>> >>> >>> -ch >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From michael.cook at wanadoo.fr Sat Nov 14 23:17:49 2009 From: michael.cook at wanadoo.fr (mike cook) Date: Sun, 15 Nov 2009 00:17:49 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) References: <4AFF15CA.1000704@murgatroid.com><2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com><15f4093efb962d5630fc0ec5eb1ed7ab.squirrel@webmail.montana.com> <2297.12.6.201.202.1258238126.squirrel@popacctsnew.quik.com> Message-ID: <001f01ca6580$aeee6a00$3401a8c0@solectron> I was thinking about the costs side as well. From the 2010 budget info I have been able to find, "The savings could top $36 million in 2010", with something like $190M over the following 5 years. I think that the GPS birds are far more than that to maintain and replace. I found the following in a May 2009 article which indicates there may even be some question on the GPS service quality in the near future. The U.S. Government Accountability Office has identified that the USAF-run GPS satellite constellation is in trouble. There are currently 30 satellites in orbit, the 24 needed for the system and six spares, which sounds like enough to run the system. The problem is that many of the satellites are getting old and will need replacing soon or will fail. The USAF has a program to replace the satellites, but it is US$1B over budget and almost three years behind schedule. U.S. Government Accountability Office recently said that it "is uncertain whether the air force will be able to acquire new satellites in time to maintain current GPS service without interruption...there will be an increased likelihood that in 2010, as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the U.S. government commits to." Why not keep LORAN and drop one spare bird. ----- Original Message ----- From: "J. Forster" To: "Don Latham" Cc: "Discussion of precise time and frequency measurement" Sent: Saturday, November 14, 2009 11:35 PM Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) > > OK, so who is in a position to MAKE them care? How about those who > understand this is a Homeland Security (among other) issue? Perhaps FOX > news? > > Likely LORAN costs about as much a year as a mile of fence along the > Mexican border, probably less. > > FWIW, > -John > > ================ > >> You've hit it on the nose. NONE of them are interested in anything but >> social issues. LORAN will not get any of them re-elected, and that's all >> any of 'em care about. >> Don >> >> J. Forster >>> Does anybody know who in Congress might take the lead in reversing the >>> decision? None of the reps in this state are at all likely to give a >>> damn. >>> Their interest is apparently only in social issues. >>> >>> -John >>> >>> ===================== >>> >>>> AOPA is pushing congress to repristinate funding for LORAN. General >>>> aviation is probably the heaviest user on this Nav system. The >>>> aviation user community would love to see Nav systems with integrated >>>> LORAN and GPS capabilty, but the industry has done little in this >>>> area, due to lack of government commitment to LORAN. The FAA knows the >>>> GPS can be easily jammed, but has done nothing do push LORAN as the >>>> GPS backup system. >>>> >>>> Sent from my iPhone >>>> >>>> >>>> On Nov 14, 2009, at 2:40 PM, Christopher Hoover >>>> wrote: >>>> >>>>> David I. Emery wrote: >>>>>> I have emailed my brother in law who is a rear admiral (I think >>>>>> now called a vice admiral) and currently CFO of the USCG (and as a >>>>>> note >>>>>> re your alma mater a MIT Sloan grad) and rather loudly said so >>>>>> myself. He most likely was part of the group that made the >>>>>> decision... I intend >>>>>> to ask him why they did it when I next see him. >>>>> >>>>> David, >>>>> >>>>> I see three possibilities: a) modernization (E-LORAN), b) maintain >>>>> existing service and capabilities, c) shut it down. >>>>> >>>>> It would be helpful to know if USCG supports the plan to shut the >>>>> system down. >>>>> If USCG does not, those of us who are US citizens can lobby Congress >>>>> to restore funding for the service. There's an educational piece >>>>> here to do. >>>>> >>>>> >>>>> -ch >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- time-nuts at febo.com >>>>> To unsubscribe, go to >>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>>> and follow the instructions there. >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts at febo.com >>>> To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> >> -- >> Dr. Don Latham AJ7LL >> Six Mile Systems LLP >> 17850 Six Mile Road >> POB 134 >> Huson, MT, 59846 >> VOX 406-626-4304 >> www.lightningforensics.com >> www.sixmilesystems.com >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jfor at quik.com Sat Nov 14 23:28:57 2009 From: jfor at quik.com (J. Forster) Date: Sat, 14 Nov 2009 15:28:57 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <001f01ca6580$aeee6a00$3401a8c0@solectron> References: <4AFF15CA.1000704@murgatroid.com><2226.12.6.201.202.1258233980.squirrel@popacctsnew.quik.com><15f4093efb962d5630fc0ec5eb1ed7ab.squirrel@webmail.montana.com> <2297.12.6.201.202.1258238126.squirrel@popacctsnew.quik.com> <001f01ca6580$aeee6a00$3401a8c0@solectron> Message-ID: <2400.12.6.201.202.1258241337.squirrel@popacctsnew.quik.com> Somehow, I think they will keep GPS running whatever the cost. There is a huge civilian constituency (everybody who cannot or is too lazy to read a map) and relies on GPS to guide their Lexus to the nearest Starbucks. Also, the military needs it to guide and target munitions. The initial Afgahnistan victories over the Taliban would have been impossible without GPS and the Special Forces teams. The folly of the decision will likely not become apparent until there is a major tragedy of some kind. Frankly, I doubt that $190 M would buy a single GPS bird and launch today. -John ================ > I was thinking about the costs side as well. From the 2010 budget info I > have been able to find, "The savings could top $36 million in 2010", with > something like $190M over the following 5 years. > > I think that the GPS birds are far more than that to maintain and replace. > I > found the following in a May 2009 article which indicates there may even > be > some question on the GPS service quality in the near future. > > The U.S. Government Accountability Office has identified that the USAF-run > GPS satellite constellation is in trouble. There are currently 30 > satellites > in orbit, the 24 needed for the system and six spares, which sounds like > enough to run the system. The problem is that many of the satellites are > getting old and will need replacing soon or will fail. The USAF has a > program to replace the satellites, but it is US$1B over budget and almost > three years behind schedule. > > U.S. Government Accountability Office recently said that it "is uncertain > whether the air force will be able to acquire new satellites in time to > maintain current GPS service without interruption...there will be an > increased likelihood that in 2010, as old satellites begin to fail, the > overall GPS constellation will fall below the number of satellites > required > to provide the level of GPS service that the U.S. government commits to." > > Why not keep LORAN and drop one spare bird. > > > ----- Original Message ----- > From: "J. Forster" > To: "Don Latham" > Cc: "Discussion of precise time and frequency measurement" > > Sent: Saturday, November 14, 2009 11:35 PM > Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator > accuracy) > > >> >> OK, so who is in a position to MAKE them care? How about those who >> understand this is a Homeland Security (among other) issue? Perhaps FOX >> news? >> >> Likely LORAN costs about as much a year as a mile of fence along the >> Mexican border, probably less. >> >> FWIW, >> -John >> >> ================ >> >>> You've hit it on the nose. NONE of them are interested in anything but >>> social issues. LORAN will not get any of them re-elected, and that's >>> all >>> any of 'em care about. >>> Don >>> >>> J. Forster >>>> Does anybody know who in Congress might take the lead in reversing the >>>> decision? None of the reps in this state are at all likely to give a >>>> damn. >>>> Their interest is apparently only in social issues. >>>> >>>> -John >>>> >>>> ===================== >>>> >>>>> AOPA is pushing congress to repristinate funding for LORAN. General >>>>> aviation is probably the heaviest user on this Nav system. The >>>>> aviation user community would love to see Nav systems with integrated >>>>> LORAN and GPS capabilty, but the industry has done little in this >>>>> area, due to lack of government commitment to LORAN. The FAA knows >>>>> the >>>>> GPS can be easily jammed, but has done nothing do push LORAN as the >>>>> GPS backup system. >>>>> From paulswedb at gmail.com Sat Nov 14 23:32:16 2009 From: paulswedb at gmail.com (paul swed) Date: Sat, 14 Nov 2009 18:32:16 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4AFF15CA.1000704@murgatroid.com> References: <4AFF15CA.1000704@murgatroid.com> Message-ID: Indeed the uscg did agree to shut it down. They signed off on it. On Sat, Nov 14, 2009 at 3:40 PM, Christopher Hoover wrote: > David I. Emery wrote: > >> I have emailed my brother in law who is a rear admiral (I think >> now called a vice admiral) and currently CFO of the USCG (and as a note >> re your alma mater a MIT Sloan grad) and rather loudly said so myself. He >> most likely was part of the group that made the decision... I intend >> to ask him why they did it when I next see him. >> > > David, > > I see three possibilities: a) modernization (E-LORAN), b) maintain existing > service and capabilities, c) shut it down. > > It would be helpful to know if USCG supports the plan to shut the system > down. > If USCG does not, those of us who are US citizens can lobby Congress to > restore funding for the service. There's an educational piece here to do. > > > -ch > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jfor at quik.com Sat Nov 14 23:33:34 2009 From: jfor at quik.com (J. Forster) Date: Sat, 14 Nov 2009 15:33:34 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4AFF15CA.1000704@murgatroid.com> Message-ID: <2410.12.6.201.202.1258241614.squirrel@popacctsnew.quik.com> There is a difference between falling off a cliff and being pushed. -John ========== > Indeed the uscg did agree to shut it down. > They signed off on it. > > On Sat, Nov 14, 2009 at 3:40 PM, Christopher Hoover > wrote: > >> David I. Emery wrote: >> >>> I have emailed my brother in law who is a rear admiral (I think >>> now called a vice admiral) and currently CFO of the USCG (and as a note >>> re your alma mater a MIT Sloan grad) and rather loudly said so myself. >>> He >>> most likely was part of the group that made the decision... I intend >>> to ask him why they did it when I next see him. >>> >> >> David, From masondg44 at comcast.net Sat Nov 14 23:55:24 2009 From: masondg44 at comcast.net (Dave M) Date: Sat, 14 Nov 2009 18:55:24 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) References: Message-ID: <689446078EEF4D10A5C4A17D76782D4A@D77M7BF1> I've read and heard from this forum as well as a number of other sources that GPS can be easily jammed. What makes GPS so vulnerable? How can it be jammed? -- David masondg44 at comcast dot net From: Francesco Ledda Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) To: Discussion of precise time and frequency measurement Cc: "time-nuts at febo.com" Message-ID: Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes AOPA is pushing congress to repristinate funding for LORAN. General aviation is probably the heaviest user on this Nav system. The aviation user community would love to see Nav systems with integrated LORAN and GPS capabilty, but the industry has done little in this area, due to lack of government commitment to LORAN. The FAA knows the GPS can be easily jammed, but has done nothing do push LORAN as the GPS backup system. Sent from my iPhone From james.p.lux at jpl.nasa.gov Sat Nov 14 23:58:50 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Sat, 14 Nov 2009 15:58:50 -0800 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2400.12.6.201.202.1258241337.squirrel@popacctsnew.quik.com> Message-ID: On 11/14/09 3:28 PM, "J. Forster" wrote: > Somehow, I think they will keep GPS running whatever the cost. There is a > huge civilian constituency (everybody who cannot or is too lazy to read a > map) and relies on GPS to guide their Lexus to the nearest Starbucks. > > Also, the military needs it to guide and target munitions. The initial > Afgahnistan victories over the Taliban would have been impossible without > GPS and the Special Forces teams. > > The folly of the decision will likely not become apparent until there is a > major tragedy of some kind. > > Frankly, I doubt that $190 M would buy a single GPS bird and launch today. > I'll bet $190M would buy the bird and launch. The typical LEO science satellite runs about $50M to put into orbit (i.e. Deliver ready to integrate satellite to whereever, and $50M later, it's in orbit). The MEO orbit for GPS might be a bit more expensive, but not hugely. Launching several hundred kilos to Mars or the Moon runs about $100M. If you're building multiple satellites that are truly identical, then a recurring cost of $50M each is totally believable. Again, for context, the typical small earth orbiting science satellite typically has a total project budget (exclusive of launch) of around $100M, and that's to do multiple instruments, get the bus, integrate, etc.. A larger "Discovery class" (e.g. Messenger, Dawn, Deep Impact, Genesis, Kepler) mission would be in the $350-400M range. New Frontiers class (New Horizons to Pluto, Juno to Jupiter) are in the $750M range (650 for spacecraft, 100 for launch), Flagship are the multi-billion dollar (e.g. Cassini) From jgray at zianet.com Sun Nov 15 00:23:43 2009 From: jgray at zianet.com (Joseph Gray) Date: Sat, 14 Nov 2009 17:23:43 -0700 Subject: [time-nuts] OCXO pinout Message-ID: I have an OCXO in a small, round metal can with an 8-pin base (like an octal tube). The label on the top has the following information. Type T-29-3BB 5070766 1000 KC 115V 75C Piezo Carlisle, PA I've done some Googling, but haven't turned up anything yet. What I am looking for is the pinout of the 8-pin connector. Joe Gray KA5ZEC From jfor at quik.com Sun Nov 15 00:22:13 2009 From: jfor at quik.com (J. Forster) Date: Sat, 14 Nov 2009 16:22:13 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <689446078EEF4D10A5C4A17D76782D4A@D77M7BF1> References: <689446078EEF4D10A5C4A17D76782D4A@D77M7BF1> Message-ID: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> Signal strength. LORAN transmitters put out multi-hundred KW to MegaWatt class pulses. Wiki has a list. I would think a GPS bird puts out less than 100 Watts CW. Also, GPS birds are a LOT farther away, especially measured in wavelengths (much higher path loss) Those factors combine to make a huge difference in received power. It could well be over 100 dB. From hmurray at megapathdsl.net Sun Nov 15 01:13:05 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sat, 14 Nov 2009 17:13:05 -0800 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Message from "Dave M" of "Sat, 14 Nov 2009 18:55:24 EST." <689446078EEF4D10A5C4A17D76782D4A@D77M7BF1> Message-ID: <20091115011306.048DEBCFC@ip-64-139-1-69.sjc.megapath.net> > I've read and heard from this forum as well as a number of other > sources that GPS can be easily jammed. What makes GPS so vulnerable? > How can it be jammed? The signal is very very very weak. The question is not how can it be jammed, but rather how can you find the signal at all. There was a recent message here reporting on the 5th harmonic of a small 315 MHz radio link wiping out GPS for a 1/2 mile: http://www.mail-archive.com/time-nuts at febo.com/msg22033.html Here is a good story: Unjamming a Coast Harbor James R. Clynch, Andrew A. Parker, George Badger, Wilbur R. Vincent, Paul McGill, Richard W. Adler GPS World, Jan 1, 2003 http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776 -- These are my opinions, not necessarily my employer's. I hate spam. From wb6bnq at cox.net Sun Nov 15 01:17:02 2009 From: wb6bnq at cox.net (WB6BNQ) Date: Sat, 14 Nov 2009 17:17:02 -0800 Subject: [time-nuts] OCXO pinout References: Message-ID: <4AFF568E.611B60BF@cox.net> Joe, Usually this type of crystal holder is referred to as a bang-bang oven can. That is the winding is controlled through a on/off thermal switch. On the unlikely side it could have a simple thermister and a power transistor for a simple analog method. With the octal plug system there should be some small screws around the base that if removed would allow the can to be lifted off the base. If that is the case you would then see an internal metal can with another lid covering where the crystal is plugged into a socket inside the internal can. If that is the case you would also be able to see the wires to the base. Then you could use an Ohmmeter to trace out the connections. If you do not feel this is the case, can you supply some pictures ? Bill....WB6BNQ Joseph Gray wrote: > I have an OCXO in a small, round metal can with an 8-pin base (like an > octal tube). The label on the top has the following information. > > Type > T-29-3BB > 5070766 > 1000 KC > 115V 75C > Piezo > Carlisle, PA > > I've done some Googling, but haven't turned up anything yet. What I am > looking for is the pinout of the 8-pin connector. > > Joe Gray > KA5ZEC > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From jgray at zianet.com Sun Nov 15 03:17:40 2009 From: jgray at zianet.com (Joseph Gray) Date: Sat, 14 Nov 2009 20:17:40 -0700 Subject: [time-nuts] OCXO pinout In-Reply-To: <4AFF568E.611B60BF@cox.net> References: <4AFF568E.611B60BF@cox.net> Message-ID: Bill, Thanks for the info. I took the can apart, but I couldn't see the wires. I'll just have to figure it out. Joe Gray KA5ZEC On Sat, Nov 14, 2009 at 6:17 PM, WB6BNQ wrote: > Joe, > > Usually this type of crystal holder is referred to as a bang-bang oven can. ?That > is the winding is controlled through a on/off thermal switch. ?On the unlikely > side it could have a simple thermister and a power transistor for a simple analog > method. > > With the octal plug system there should be some small screws around the base that > if removed would allow the can to be lifted off the base. ?If that is the case > you would then see an internal metal can with another lid covering where the > crystal is plugged into a socket inside the internal can. > > If that is the case you would also be able to see the wires to the base. ?Then > you could use an Ohmmeter to trace out the connections. > > If you do not feel this is the case, can you supply some pictures ? > > Bill....WB6BNQ > > > Joseph Gray wrote: > >> I have an OCXO in a small, round metal can with an 8-pin base (like an >> octal tube). The label on the top has the following information. >> >> Type >> T-29-3BB >> 5070766 >> 1000 KC >> 115V ?75C >> Piezo >> Carlisle, PA >> >> I've done some Googling, but haven't turned up anything yet. What I am >> looking for is the pinout of the 8-pin connector. >> >> Joe Gray >> KA5ZEC >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From frledda at verizon.net Sun Nov 15 03:21:47 2009 From: frledda at verizon.net (Francesco Ledda) Date: Sat, 14 Nov 2009 21:21:47 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <20091115011306.048DEBCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: LORAN is a good back up, but it has problems and limitations. Navigating next to a storm can overwhelm the receiver and make it unusable. The LORAN system doesn't have a build in accuracy degradation system like GPS(RAIM - receiver autonomous integrity monitoring), and this make LORAN unfit to fly Non-Vertical Guidance approaches. GPS with its accurate positioning, fast update rate and WAAS make is an awesome aircraft navigation system that can replace almost all NAVAIDS including ILS. Today with GPS, we can fly in instrument conditions from take off to landing without ever tuning any external NAVAID; not even INS can't do that. It is pretty amazing to me! -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of Hal Murray Sent: Saturday, November 14, 2009 7:13 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) > I've read and heard from this forum as well as a number of other > sources that GPS can be easily jammed. What makes GPS so vulnerable? > How can it be jammed? The signal is very very very weak. The question is not how can it be jammed, but rather how can you find the signal at all. There was a recent message here reporting on the 5th harmonic of a small 315 MHz radio link wiping out GPS for a 1/2 mile: http://www.mail-archive.com/time-nuts at febo.com/msg22033.html Here is a good story: Unjamming a Coast Harbor James R. Clynch, Andrew A. Parker, George Badger, Wilbur R. Vincent, Paul McGill, Richard W. Adler GPS World, Jan 1, 2003 http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776 -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ From jltran at worldnet.att.net Sun Nov 15 03:41:24 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sat, 14 Nov 2009 21:41:24 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Message-ID: <50877A0A32E6458EB787702EDC9E7F93@S0028384766> I have been a private pilot for 40+ years, hold an Airline Transport Pilot rating and am very interested in 'redundancy'. I very much like the availability of GPS, LORAN, VOR, ADF, and ILS but have never been able to afford INS. However, I recognize the we (the USA) have limited resources (national debt in excess of $8T) and we must stop spending on something. If it were up to me, I would stop spending on other things. However, I, for one, am glad that they decided to stop spending on something. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Francesco Ledda Sent: Saturday, November 14, 2009 9:22 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) LORAN is a good back up, but it has problems and limitations. Navigating next to a storm can overwhelm the receiver and make it unusable. The LORAN system doesn't have a build in accuracy degradation system like GPS(RAIM - receiver autonomous integrity monitoring), and this make LORAN unfit to fly Non-Vertical Guidance approaches. GPS with its accurate positioning, fast update rate and WAAS make is an awesome aircraft navigation system that can replace almost all NAVAIDS including ILS. Today with GPS, we can fly in instrument conditions from take off to landing without ever tuning any external NAVAID; not even INS can't do that. It is pretty amazing to me! -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of Hal Murray Sent: Saturday, November 14, 2009 7:13 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) > I've read and heard from this forum as well as a number of other > sources that GPS can be easily jammed. What makes GPS so vulnerable? > How can it be jammed? The signal is very very very weak. The question is not how can it be jammed, but rather how can you find the signal at all. There was a recent message here reporting on the 5th harmonic of a small 315 MHz radio link wiping out GPS for a 1/2 mile: http://www.mail-archive.com/time-nuts at febo.com/msg22033.html Here is a good story: Unjamming a Coast Harbor James R. Clynch, Andrew A. Parker, George Badger, Wilbur R. Vincent, Paul McGill, Richard W. Adler GPS World, Jan 1, 2003 http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776 -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From glennmaillist at bellsouth.net Sun Nov 15 03:47:36 2009 From: glennmaillist at bellsouth.net (Glenn Little WB4UIV) Date: Sat, 14 Nov 2009 22:47:36 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <20091115011306.048DEBCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <6.2.3.4.2.20091114223920.0511e5d0@mail.bellsouth.net> And all the GPS goodness can easily be disabled by a missile and a near nuclear burst or a portable handheld jammer at the airport. The portable handheld jammer is a very real threat to GPS due to the signal levels from the satellite. Now they are trying to revive a miswired SVN and add it to the network. It is very hard to jam the LORAN signal without a high power jammer. If a LORAN station is taken out by enemy action, it is not unreasonable to rebuild or replace it. GPS is just too fragile to be heavily relied on. I know that we do it every day, but, you need to have a backup navigation system. LORAN is time proven to be functional and the technology is in place on a number of platforms to utilize it. 73 Glenn WB4UIV ETCS(SS) USN Retired (Electronic Navigation) At 10:21 PM 11/14/2009, Francesco Ledda wrote: >LORAN is a good back up, but it has problems and limitations. Navigating >next to a storm can overwhelm the receiver and make it unusable. The LORAN >system doesn't have a build in accuracy degradation system like GPS(RAIM - >receiver autonomous integrity monitoring), and this make LORAN unfit to fly >Non-Vertical Guidance approaches. GPS with its accurate positioning, fast >update rate and WAAS make is an awesome aircraft navigation system that can >replace almost all NAVAIDS including ILS. Today with GPS, we can fly in >instrument conditions from take off to landing without ever tuning any >external NAVAID; not even INS can't do that. It is pretty amazing to me! > > > > > > >-----Original Message----- >From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On >Behalf Of Hal Murray >Sent: Saturday, November 14, 2009 7:13 PM >To: Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference >oscillator accuracy) > > > > > I've read and heard from this forum as well as a number of other > > sources that GPS can be easily jammed. What makes GPS so vulnerable? > > How can it be jammed? > >The signal is very very very weak. The question is not how can it be >jammed, >but rather how can you find the signal at all. > >There was a recent message here reporting on the 5th harmonic of a small 315 >MHz radio link wiping out GPS for a 1/2 mile: > http://www.mail-archive.com/time-nuts at febo.com/msg22033.html > >Here is a good story: > Unjamming a Coast Harbor > James R. Clynch, Andrew A. Parker, George Badger, > Wilbur R. Vincent, Paul McGill, Richard W. Adler > GPS World, Jan 1, 2003 > http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776 > > > >-- >These are my opinions, not necessarily my employer's. I hate spam. > > > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > > > > >E-mail message checked by Spyware Doctor (6.0.0.386) >Database version: 5.13700 >http://www.pctools.com/en/spyware-doctor-antivirus/ > > > > > >E-mail message checked by Spyware Doctor (6.0.0.386) >Database version: 5.13700 >http://www.pctools.com/en/spyware-doctor-antivirus/ > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From jfor at quik.com Sun Nov 15 04:00:39 2009 From: jfor at quik.com (J. Forster) Date: Sat, 14 Nov 2009 20:00:39 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <6.2.3.4.2.20091114223920.0511e5d0@mail.bellsouth.net> References: <20091115011306.048DEBCFC@ip-64-139-1-69.sjc.megapath.net> <6.2.3.4.2.20091114223920.0511e5d0@mail.bellsouth.net> Message-ID: <3128.12.6.201.202.1258257639.squirrel@popacctsnew.quik.com> Agreed. Furthermore, a GPS jammer is VERY hard to locate because the signal levels are so low. An effective LORAN jammer could easily be DF'd with a foot sized loop and tuning capacitor resonating at 100KHz, diode detector, and a set of headphones. It would be IMPOSSIBLE to hide. If a LORAN transmitter were destroyed by a terrorist team, a backup could be in operation in hours. A damaged GPS system could easily take many months or even years to fix. -John ================ > And all the GPS goodness can easily be disabled by a missile and a > near nuclear burst or a portable handheld jammer at the airport. > The portable handheld jammer is a very real threat to GPS due to the > signal levels from the satellite. > > Now they are trying to revive a miswired SVN and add it to the network. > > It is very hard to jam the LORAN signal without a high power jammer. > If a LORAN station is taken out by enemy action, it is not > unreasonable to rebuild or replace it. > > GPS is just too fragile to be heavily relied on. > > I know that we do it every day, but, you need to have a backup > navigation system. > > LORAN is time proven to be functional and the technology is in place > on a number of platforms to utilize it. > > > 73 > Glenn > WB4UIV > ETCS(SS) USN Retired (Electronic Navigation) > > At 10:21 PM 11/14/2009, Francesco Ledda wrote: >>LORAN is a good back up, but it has problems and limitations. Navigating >>next to a storm can overwhelm the receiver and make it unusable. The >> LORAN >>system doesn't have a build in accuracy degradation system like GPS(RAIM >> - >>receiver autonomous integrity monitoring), and this make LORAN unfit to >> fly >>Non-Vertical Guidance approaches. GPS with its accurate positioning, fast >>update rate and WAAS make is an awesome aircraft navigation system that >> can >>replace almost all NAVAIDS including ILS. Today with GPS, we can fly in >>instrument conditions from take off to landing without ever tuning any >>external NAVAID; not even INS can't do that. It is pretty amazing to me! >> >> >> >> >> >> >>-----Original Message----- >>From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On >>Behalf Of Hal Murray >>Sent: Saturday, November 14, 2009 7:13 PM >>To: Discussion of precise time and frequency measurement >>Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference >>oscillator accuracy) >> >> >> >> > I've read and heard from this forum as well as a number of other >> > sources that GPS can be easily jammed. What makes GPS so vulnerable? >> > How can it be jammed? >> >>The signal is very very very weak. The question is not how can it be >>jammed, >>but rather how can you find the signal at all. >> >>There was a recent message here reporting on the 5th harmonic of a small >> 315 >>MHz radio link wiping out GPS for a 1/2 mile: >> http://www.mail-archive.com/time-nuts at febo.com/msg22033.html >> >>Here is a good story: >> Unjamming a Coast Harbor >> James R. Clynch, Andrew A. Parker, George Badger, >> Wilbur R. Vincent, Paul McGill, Richard W. Adler >> GPS World, Jan 1, 2003 >> http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776 >> >> >> >>-- >>These are my opinions, not necessarily my employer's. I hate spam. >> >> >> >> >>_______________________________________________ >>time-nuts mailing list -- time-nuts at febo.com >>To unsubscribe, go to >>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>and follow the instructions there. >> >> >> >> >>E-mail message checked by Spyware Doctor (6.0.0.386) >>Database version: 5.13700 >>http://www.pctools.com/en/spyware-doctor-antivirus/ >> >> >> >> >> >>E-mail message checked by Spyware Doctor (6.0.0.386) >>Database version: 5.13700 >>http://www.pctools.com/en/spyware-doctor-antivirus/ >> >>_______________________________________________ >>time-nuts mailing list -- time-nuts at febo.com >>To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bg at lysator.liu.se Sun Nov 15 07:28:36 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 15 Nov 2009 08:28:36 +0100 (CET) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <3128.12.6.201.202.1258257639.squirrel@popacctsnew.quik.com> References: <20091115011306.048DEBCFC@ip-64-139-1-69.sjc.megapath.net> <6.2.3.4.2.20091114223920.0511e5d0@mail.bellsouth.net> <3128.12.6.201.202.1258257639.squirrel@popacctsnew.quik.com> Message-ID: <62601.87.227.52.225.1258270116.squirrel@webmail.lysator.liu.se> John, > If a LORAN transmitter were destroyed by a terrorist team, a backup could > be in operation in hours. A damaged GPS system could easily take many > months or even years to fix. > > -John A LORAN site, with a several hundred meter high mast, a small house full of transmitter, signal generation and Cs clock(s?)... on a remote Norwegian island... would not be back online within a few hours after an attack. GPS is supposed to work without _any_ terrestrial support for days or weeks. I doubt that anyone can get something lethal for the SVs up in orbit without making it very obvious who they are. GPS now has lots of hot spare birds in orbit, that a instantly online with one or a few satellites going bust. That said, I think LORAN should be kept running as a backup, also with a firm commitment that it WILL KEEP running for 10+ years, giving vendors a reason to develop modern receivers. -- Bj?rn From robert8rpi at yahoo.co.uk Sun Nov 15 10:28:22 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Sun, 15 Nov 2009 10:28:22 +0000 (GMT) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <62601.87.227.52.225.1258270116.squirrel@webmail.lysator.liu.se> Message-ID: <468083.55515.qm@web27104.mail.ukl.yahoo.com> I agree with the commitment comment. Here in the UK we were just starting to see affordable Decca Navigator receivers using mdern (microprocessor) technology when they shut the system down. I prsonally think that the big driver is that the military don't use LORAN. They have GPS and inertial (ships as well as aircraft, even some land vehicles) and are content to let LORAN go. ? Robert G8RPI. --- On Sun, 15/11/09, bg at lysator.liu.se wrote: From: bg at lysator.liu.se Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) To: jfor at quik.com, "Discussion of precise time and frequency measurement" Date: Sunday, 15 November, 2009, 7:28 John, > If a LORAN transmitter were destroyed by a terrorist team, a backup could > be in operation in hours. A damaged GPS system could easily take many > months or even years to fix. > > -John A LORAN site, with a several hundred meter high mast, a small house full of transmitter, signal generation and Cs clock(s?)... on a remote Norwegian island... would not be back online within a few hours after an attack. GPS is supposed to work without _any_ terrestrial support for days or weeks. I doubt that anyone can get something lethal for the SVs up in orbit without making it very obvious who they are. GPS now has lots of hot spare birds in orbit, that a instantly online with one or a few satellites going bust. That said, I think LORAN should be kept running as a backup, also with a firm commitment that it WILL KEEP running for 10+ years, giving vendors a reason to develop modern receivers. -- ???Bj?rn _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Sun Nov 15 15:01:20 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 15 Nov 2009 16:01:20 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <62601.87.227.52.225.1258270116.squirrel@webmail.lysator.liu.se> References: <20091115011306.048DEBCFC@ip-64-139-1-69.sjc.megapath.net> <6.2.3.4.2.20091114223920.0511e5d0@mail.bellsouth.net> <3128.12.6.201.202.1258257639.squirrel@popacctsnew.quik.com> <62601.87.227.52.225.1258270116.squirrel@webmail.lysator.liu.se> Message-ID: <4B0017C0.3080905@rubidium.dyndns.org> bg at lysator.liu.se wrote: > John, > >> If a LORAN transmitter were destroyed by a terrorist team, a backup could >> be in operation in hours. A damaged GPS system could easily take many >> months or even years to fix. >> >> -John > > A LORAN site, with a several hundred meter high mast, a small house full > of transmitter, signal generation and Cs clock(s?)... on a remote > Norwegian island... would not be back online within a few hours after an > attack. Regardless of location, it will take some time to restore functionality. About a year maybe. The LORAN-C station would reduce navigation in a certain area. However, since most "interesting" targets use GPS, it is a more interesting target. > GPS is supposed to work without _any_ terrestrial support for days or > weeks. I doubt that anyone can get something lethal for the SVs up in > orbit without making it very obvious who they are. GPS now has lots of hot > spare birds in orbit, that a instantly online with one or a few satellites > going bust. The AutoNAV feature should keep it up for 180 days. It has never been used. Essentially, what if you wipe out the ground segment and needs to rebuild it. The ground segment points of GPS is fewer than the LORAN-C stations. Firing rockets to down the birds is above the average terrorist budget and infrastructure. While not all 30 GPS birds needs to go down, a significant number of them needs to for a significant system impact. Downing a single of them is sufficient for the political effect, so that is more likely. Using jammers is far more likely. It has been analyzed quite deeply. It is not impossible to locate a GPS jammer. In Iraq, they had relative high power jammers and they where able to locate them and finally take them out. > That said, I think LORAN should be kept running as a backup, also with a > firm commitment that it WILL KEEP running for 10+ years, giving vendors a > reason to develop modern receivers. The electronics needed to support LORAN-C and eLORAN is not very complex by todays measure. Could be integrated with a GPS receiver. Cheers, Magnus From frledda at verizon.net Sun Nov 15 15:28:13 2009 From: frledda at verizon.net (Francesco Ledda) Date: Sun, 15 Nov 2009 09:28:13 -0600 Subject: [time-nuts] FS HP103 Precision Crystal Reference In-Reply-To: <4B0017C0.3080905@rubidium.dyndns.org> Message-ID: Nice looking, no mods. $115 plus shipping from 75044. Thank you! Francesco Ledda Garland, Texas -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of Magnus Danielson Sent: Sunday, November 15, 2009 9:01 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) bg at lysator.liu.se wrote: > John, > >> If a LORAN transmitter were destroyed by a terrorist team, a backup could >> be in operation in hours. A damaged GPS system could easily take many >> months or even years to fix. >> >> -John > > A LORAN site, with a several hundred meter high mast, a small house full > of transmitter, signal generation and Cs clock(s?)... on a remote > Norwegian island... would not be back online within a few hours after an > attack. Regardless of location, it will take some time to restore functionality. About a year maybe. The LORAN-C station would reduce navigation in a certain area. However, since most "interesting" targets use GPS, it is a more interesting target. > GPS is supposed to work without _any_ terrestrial support for days or > weeks. I doubt that anyone can get something lethal for the SVs up in > orbit without making it very obvious who they are. GPS now has lots of hot > spare birds in orbit, that a instantly online with one or a few satellites > going bust. The AutoNAV feature should keep it up for 180 days. It has never been used. Essentially, what if you wipe out the ground segment and needs to rebuild it. The ground segment points of GPS is fewer than the LORAN-C stations. Firing rockets to down the birds is above the average terrorist budget and infrastructure. While not all 30 GPS birds needs to go down, a significant number of them needs to for a significant system impact. Downing a single of them is sufficient for the political effect, so that is more likely. Using jammers is far more likely. It has been analyzed quite deeply. It is not impossible to locate a GPS jammer. In Iraq, they had relative high power jammers and they where able to locate them and finally take them out. > That said, I think LORAN should be kept running as a backup, also with a > firm commitment that it WILL KEEP running for 10+ years, giving vendors a > reason to develop modern receivers. The electronics needed to support LORAN-C and eLORAN is not very complex by todays measure. Could be integrated with a GPS receiver. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ From frledda at verizon.net Sun Nov 15 15:37:51 2009 From: frledda at verizon.net (Francesco Ledda) Date: Sun, 15 Nov 2009 09:37:51 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B0017C0.3080905@rubidium.dyndns.org> Message-ID: The bottom line is simple: the military don't need it, the FAA see no value in it; the avionics industry has discontinued the manufacturing of LORAN receivers years ago, the General Aviation community has bigger fish to fry (fight user fees); the Europen talked in the past about using LORAN for redundancy purposes, but never issued any concrete plans or requisitions. For all above reasons, LORAN is going to go. As a pilot, my personal experience about LORAN is mixed. Two times in heavy IMC, using RNAV LORAN, the LORAN went out in crytical phases of flight. This has never happened to me, with GPS. -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of Magnus Danielson Sent: Sunday, November 15, 2009 9:01 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) bg at lysator.liu.se wrote: > John, > >> If a LORAN transmitter were destroyed by a terrorist team, a backup could >> be in operation in hours. A damaged GPS system could easily take many >> months or even years to fix. >> >> -John > > A LORAN site, with a several hundred meter high mast, a small house full > of transmitter, signal generation and Cs clock(s?)... on a remote > Norwegian island... would not be back online within a few hours after an > attack. Regardless of location, it will take some time to restore functionality. About a year maybe. The LORAN-C station would reduce navigation in a certain area. However, since most "interesting" targets use GPS, it is a more interesting target. > GPS is supposed to work without _any_ terrestrial support for days or > weeks. I doubt that anyone can get something lethal for the SVs up in > orbit without making it very obvious who they are. GPS now has lots of hot > spare birds in orbit, that a instantly online with one or a few satellites > going bust. The AutoNAV feature should keep it up for 180 days. It has never been used. Essentially, what if you wipe out the ground segment and needs to rebuild it. The ground segment points of GPS is fewer than the LORAN-C stations. Firing rockets to down the birds is above the average terrorist budget and infrastructure. While not all 30 GPS birds needs to go down, a significant number of them needs to for a significant system impact. Downing a single of them is sufficient for the political effect, so that is more likely. Using jammers is far more likely. It has been analyzed quite deeply. It is not impossible to locate a GPS jammer. In Iraq, they had relative high power jammers and they where able to locate them and finally take them out. > That said, I think LORAN should be kept running as a backup, also with a > firm commitment that it WILL KEEP running for 10+ years, giving vendors a > reason to develop modern receivers. The electronics needed to support LORAN-C and eLORAN is not very complex by todays measure. Could be integrated with a GPS receiver. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ From xde-l2g3 at myamail.com Sun Nov 15 16:37:11 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Sun, 15 Nov 2009 11:37:11 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> Message-ID: "J. Forster" wrote: >> I've read and heard from this forum as well as a number of other >> sources that GPS can be easily jammed. What makes GPS so >> vulnerable? How can it be jammed? > Signal strength. > LORAN transmitters put out multi-hundred KW to MegaWatt class > pulses. Wiki has a list. I would think a GPS bird puts out less > than 100 Watts CW. > Also, GPS birds are a LOT farther away, especially measured in > wavelengths (much higher path loss) > Those factors combine to make a huge difference in received power. > It could well be over 100 dB. >> From what I've heard a GPS jammer smaller than a deck of playing >> cards can easily wipe out GPS w/in a mile or more for a week or >> longer. > John It should be easy to locate a jammer. Go to the area where the GPS signal is being jammed. Drive in some direction until the signal is regained. Repeat to find three locations where the signal is lost. Three points define a circle. The diameter tells the strength of the jamming signal. The center defines the location. Once you are near the center, ordinary DF techniques should quickly identify the source. For faster response, have a number of GPS receivers report the status of the GPS signal to a central location. This would identify a moving jammer. It should also be possible to develop a GPS antenna with one or more nulls in the horizontal direction. Rotate the antenna until the GPS signal is regained. The null points to the jammer. Multiple receivers would remove the ambiguity from antennas with more than one null. These techniques should identify a jammer very quickly, perhaps in hours or minutes instead of weeks. I'm sure the military has some more advanced methods, as well as effective methods of dealing with the threat. Mike Monett From magnus at rubidium.dyndns.org Sun Nov 15 16:39:07 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 15 Nov 2009 17:39:07 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: Message-ID: <4B002EAB.2070809@rubidium.dyndns.org> Francesco Ledda wrote: > The bottom line is simple: the military don't need it, the FAA see no value > in it; the avionics industry has discontinued the manufacturing of LORAN > receivers years ago, the General Aviation community has bigger fish to fry > (fight user fees); the Europen talked in the past about using LORAN for > redundancy purposes, but never issued any concrete plans or requisitions. > > For all above reasons, LORAN is going to go. The time for cutting the service will come eventually. While it has serviced us well, the use is not as heavy as previous years and it has essentially been replaced by GPS. It's sad to see it go, but in times when budget is tought good old systems gets killed. Eventually they need to. For those only having LORAN-C, the investment into a GPS receiver should not be too steep. Cheers, Magnus From cfharris at erols.com Sun Nov 15 16:51:21 2009 From: cfharris at erols.com (Chuck Harris) Date: Sun, 15 Nov 2009 11:51:21 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> Message-ID: <4B003189.4050000@erols.com> I guess the point you folks aren't getting is you can make a very effective local GPS jammer that runs off of a 9V transistor radio battery, and will last for several weeks. It can be done for a total cost of a few bucks per jammer.... search the web, the designs are out there. Toss the GPS jammers indiscriminately around the landscape, and you put GPS out of business for a very low cost. -Chuck Harris Mike Monett wrote: > > It should be easy to locate a jammer. Go to the area where the GPS > signal is being jammed. Drive in some direction until the signal is > regained. Repeat to find three locations where the signal is lost. > > Three points define a circle. The diameter tells the strength of the > jamming signal. The center defines the location. > > Once you are near the center, ordinary DF techniques should quickly > identify the source. > From jfor at quik.com Sun Nov 15 17:04:54 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 09:04:54 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B0017C0.3080905@rubidium.dyndns.org> References: <20091115011306.048DEBCFC@ip-64-139-1-69.sjc.megapath.net> <6.2.3.4.2.20091114223920.0511e5d0@mail.bellsouth.net> <3128.12.6.201.202.1258257639.squirrel@popacctsnew.quik.com> <62601.87.227.52.225.1258270116.squirrel@webmail.lysator.liu.se> <4B0017C0.3080905@rubidium.dyndns.org> Message-ID: <1078.12.6.201.222.1258304694.squirrel@popacctsnew.quik.com> > bg at lysator.liu.se wrote: >> John, >> >>> If a LORAN transmitter were destroyed by a terrorist team, a backup >>> could >>> be in operation in hours. A damaged GPS system could easily take many >>> months or even years to fix. >>> >>> -John The military have air deployable radio trucks. A LORAN station could be built into a few trailers, including generator, clocks, and transmitter. There are also fielded deployable masts. Such a station could be deployed rapidly. It would not have as powerful signal as the original station, but would, IMO, be fully functional. -John >> >> A LORAN site, with a several hundred meter high mast, a small house full >> of transmitter, signal generation and Cs clock(s?)... on a remote >> Norwegian island... would not be back online within a few hours after an >> attack. > > Regardless of location, it will take some time to restore functionality. > About a year maybe. From jfor at quik.com Sun Nov 15 17:08:17 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 09:08:17 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Message-ID: <1089.12.6.201.222.1258304897.squirrel@popacctsnew.quik.com> > John, > >> If a LORAN transmitter were destroyed by a terrorist team, a backup could >> be in operation in hours. A damaged GPS system could easily take many months or even years to fix. >> >> -John > > A LORAN site, with a several hundred meter high mast, a small house full of transmitter, signal generation and Cs clock(s?)... on a remote Norwegian island... would not be back online within a few hours after an attack. I think it'd still be a lot easier to replace quickly than GPS jammers widely seeded. What would happen if some rogue country started building mini-GPS jammers and giving them to insurgents to randomly scatter around. A single donkey could carry many hundreds? Or suppose a jammer was built into a child's toy and ran intermittantly off the toy's batteries and sold by the zillions at Walmart for Christmas? > GPS is supposed to work without _any_ terrestrial support for days or weeks. I doubt that anyone can get something lethal for the SVs up in orbit without making it very obvious who they are. GPS now has lots of hot spare birds in orbit, that a instantly online with one or a few satellites going bust. I've never suggested attacking the birds is a credible terrorist threat. It is not, IMO. > That said, I think LORAN should be kept running as a backup, also with a firm commitment that it WILL KEEP running for 10+ years, giving vendors a reason to develop modern receivers. > > -- > > Bj?rn IMO, GPS is much more vulnerable to a jamming attack and LORAN must be maintained as a backup. FWIW, -John ================ From jfor at quik.com Sun Nov 15 17:23:12 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 09:23:12 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B003189.4050000@erols.com> References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> <4B003189.4050000@erols.com> Message-ID: <1103.12.6.201.222.1258305792.squirrel@popacctsnew.quik.com> Thanks Chuck, My point EXACTLY. 1. It's well within the capability of dozens of countries or organizations or even individuals. 2. They are trivial to distribute widely, and could be piggy-backed onto other things. 3. Given enough of them with random on-off cycles, you'd force a giant game of Whak-A-Mole. A guy in his basement could easily build 100 in a week given a design and PCB layout. In another week he could scatter them all over a city, even if travelling by bus. The whole operation would cost under a few thousand dollars. Furthermore, it would not be needed to kill all the GPS in an area, all the time. Making it unreliable would likely be enough. FWIW, -John ================== > I guess the point you folks aren't getting is you can make a very > effective local GPS jammer that runs off of a 9V transistor radio battery, > and will last for several weeks. It can be done for a total cost of > a few bucks per jammer.... search the web, the designs are out there. > > Toss the GPS jammers indiscriminately around the landscape, and you put > GPS out of business for a very low cost. > > -Chuck Harris > > Mike Monett wrote: >> >> It should be easy to locate a jammer. Go to the area where the GPS >> signal is being jammed. Drive in some direction until the signal is >> regained. Repeat to find three locations where the signal is lost. >> >> Three points define a circle. The diameter tells the strength of the >> jamming signal. The center defines the location. >> >> Once you are near the center, ordinary DF techniques should quickly >> identify the source. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From w1ksz at earthlink.net Sun Nov 15 17:26:56 2009 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Sun, 15 Nov 2009 10:26:56 -0700 (GMT-07:00) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Message-ID: <11603302.1258306016911.JavaMail.root@elwamui-hound.atl.sa.earthlink.net> After reading all the responses on this thread, all I can think of is the numerous ideas you folks have given some whackjob out there. Keep up the good work. 73, Dick, W1KSZ -----Original Message----- >From: Chuck Harris >Sent: Nov 15, 2009 9:51 AM >To: Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) > >I guess the point you folks aren't getting is you can make a very >effective local GPS jammer that runs off of a 9V transistor radio battery, >and will last for several weeks. It can be done for a total cost of >a few bucks per jammer.... search the web, the designs are out there. > >Toss the GPS jammers indiscriminately around the landscape, and you put >GPS out of business for a very low cost. > >-Chuck Harris > >Mike Monett wrote: >> >> It should be easy to locate a jammer. Go to the area where the GPS >> signal is being jammed. Drive in some direction until the signal is >> regained. Repeat to find three locations where the signal is lost. >> >> Three points define a circle. The diameter tells the strength of the >> jamming signal. The center defines the location. >> >> Once you are near the center, ordinary DF techniques should quickly >> identify the source. >> > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From jfor at quik.com Sun Nov 15 17:31:00 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 09:31:00 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <11603302.1258306016911.JavaMail.root@elwamui-hound.atl.sa.earthlink.n et> References: <11603302.1258306016911.JavaMail.root@elwamui-hound.atl.sa.earthlink.net> Message-ID: <1123.12.6.201.222.1258306260.squirrel@popacctsnew.quik.com> I just put "jamming GPS" into Google, and got about 348,000 hits. -John ============ > After reading all the responses on this thread, all I can think > of is the numerous ideas you folks have given some whackjob out > there. > > Keep up the good work. > > 73, Dick, W1KSZ > > -----Original Message----- >>From: Chuck Harris >>Sent: Nov 15, 2009 9:51 AM >>To: Discussion of precise time and frequency measurement >> >>Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference >> oscillator accuracy) >> >>I guess the point you folks aren't getting is you can make a very >>effective local GPS jammer that runs off of a 9V transistor radio >> battery, >>and will last for several weeks. It can be done for a total cost of >>a few bucks per jammer.... search the web, the designs are out there. >> >>Toss the GPS jammers indiscriminately around the landscape, and you put >>GPS out of business for a very low cost. >> >>-Chuck Harris >> >>Mike Monett wrote: >>> >>> It should be easy to locate a jammer. Go to the area where the GPS >>> signal is being jammed. Drive in some direction until the signal is >>> regained. Repeat to find three locations where the signal is lost. >>> >>> Three points define a circle. The diameter tells the strength of the >>> jamming signal. The center defines the location. >>> >>> Once you are near the center, ordinary DF techniques should quickly >>> identify the source. >>> >> >>_______________________________________________ >>time-nuts mailing list -- time-nuts at febo.com >>To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From ssybert at kb1fxy.us Sun Nov 15 17:43:02 2009 From: ssybert at kb1fxy.us (Scott A Sybert) Date: Sun, 15 Nov 2009 09:43:02 -0800 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) References: <11603302.1258306016911.JavaMail.root@elwamui-hound.atl.sa.earthlink.net> Message-ID: <15D717421F0B004A82877D8DFEDF912B058B54@ex14.hostedexchange.local> Exposing vulnerabilities always make for a more secure product. Hiding known security risks or possible avenues of sabotage only creates a false sense of security. I'd rather know how vulnerable GPS is and have paper maps & charts than have the false sense of security it's an untouchable system because it's high up in space or any other argument of redundancy, etc. Bottom line is, talking about the possible vulnerabilities for technical purposes isn't giving the enemy any ideas they don't already have. China shot down a weather satellite a few years ago testing a rocket. You don't think there was an underlying message to that? Believe me, The enemy has ideas AND capabilities we haven't even come close to covering. And my opinion, Maybe Obama should take one less flight to Europe talking down about his own nation and spend that 190M on supporting LORAN for the next 10 years (obviously inflated flight costs but you get the picture) Lets face it, the arugment about saving money shouldn't start on cancelling FUNCTIONAL and NECESSARY programs. There's plenty of earmarks, bailouts and other waste that we could EASILY cancel to come up with the 190M required to keep this NAVIGATION system online another decade. Just my two cents. Regards, Scott CISSP. ________________________________ From: time-nuts-bounces at febo.com on behalf of Richard W. Solomon Sent: Sun 11/15/2009 12:26 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) After reading all the responses on this thread, all I can think of is the numerous ideas you folks have given some whackjob out there. Keep up the good work. 73, Dick, W1KSZ -----Original Message----- >From: Chuck Harris >Sent: Nov 15, 2009 9:51 AM >To: Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) > >I guess the point you folks aren't getting is you can make a very >effective local GPS jammer that runs off of a 9V transistor radio battery, >and will last for several weeks. It can be done for a total cost of >a few bucks per jammer.... search the web, the designs are out there. > >Toss the GPS jammers indiscriminately around the landscape, and you put >GPS out of business for a very low cost. > >-Chuck Harris > >Mike Monett wrote: >> >> It should be easy to locate a jammer. Go to the area where the GPS >> signal is being jammed. Drive in some direction until the signal is >> regained. Repeat to find three locations where the signal is lost. >> >> Three points define a circle. The diameter tells the strength of the >> jamming signal. The center defines the location. >> >> Once you are near the center, ordinary DF techniques should quickly >> identify the source. >> > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From didier at cox.net Sun Nov 15 17:45:54 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 17:45:54 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <1103.12.6.201.222.1258305792.squirrel@popacctsnew.quik.com> References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> <4B003189.4050000@erols.com><1103.12.6.201.222.1258305792.squirrel@popacctsnew.quik.com> Message-ID: <611953893-1258307149-cardhu_decombobulator_blackberry.rim.net-673066355-@bda224.bisx.prod.on.blackberry> Enough for what? To bug the heck out of a citizen suddenly unable to find his way to the movie theater? Weapon systems and aircraft navigation are unlikely to be affected by such a simple device on the ground, even if deployed in large quantity. Most of the stuff that really needs GPS has decent antennas that look up, not down. Didier ------------------------ Sent from my BlackBerry Wireless thingy while I do other things... -----Original Message----- From: "J. Forster" Date: Sun, 15 Nov 2009 09:23:12 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Thanks Chuck, My point EXACTLY. 1. It's well within the capability of dozens of countries or organizations or even individuals. 2. They are trivial to distribute widely, and could be piggy-backed onto other things. 3. Given enough of them with random on-off cycles, you'd force a giant game of Whak-A-Mole. A guy in his basement could easily build 100 in a week given a design and PCB layout. In another week he could scatter them all over a city, even if travelling by bus. The whole operation would cost under a few thousand dollars. Furthermore, it would not be needed to kill all the GPS in an area, all the time. Making it unreliable would likely be enough. FWIW, -John ================== > I guess the point you folks aren't getting is you can make a very > effective local GPS jammer that runs off of a 9V transistor radio battery, > and will last for several weeks. It can be done for a total cost of > a few bucks per jammer.... search the web, the designs are out there. > > Toss the GPS jammers indiscriminately around the landscape, and you put > GPS out of business for a very low cost. > > -Chuck Harris > > Mike Monett wrote: >> >> It should be easy to locate a jammer. Go to the area where the GPS >> signal is being jammed. Drive in some direction until the signal is >> regained. Repeat to find three locations where the signal is lost. >> >> Three points define a circle. The diameter tells the strength of the >> jamming signal. The center defines the location. >> >> Once you are near the center, ordinary DF techniques should quickly >> identify the source. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From phk at phk.freebsd.dk Sun Nov 15 17:51:32 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 17:51:32 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 09:04:54 PST." <1078.12.6.201.222.1258304694.squirrel@popacctsnew.quik.com> Message-ID: <50229.1258307492@critter.freebsd.dk> In message <1078.12.6.201.222.1258304694.squirrel at popacctsnew.quik.com>, "J. Fo rster" writes: >The military have air deployable radio trucks. A LORAN station could be >built into a few trailers, including generator, clocks, and transmitter. >There are also fielded deployable masts. In fact, that is pretty much how the original LORAN was built... There are some very good stories about this on: http://www.loran-history.info/default.asp Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From phk at phk.freebsd.dk Sun Nov 15 17:54:09 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 17:54:09 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 11:37:11 EST." Message-ID: <50247.1258307649@critter.freebsd.dk> In message , "Mike Monett" writes: > It should be easy to locate a jammer. Go to the area where the GPS > signal is being jammed. Drive in some direction until the signal is > regained. Repeat to find three locations where the signal is lost. Experience has shown that this is far from as easy as that. For one thing, you have no assurance that the jammer has isotropic propagation and your local geometry & obstructions will determine the subset of sats you have access to. In military excercises, I have been told the average time to find a jammer is on the order of "many hours" in an "simulated urban setting", due to propagation and access issues. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From magnus at rubidium.dyndns.org Sun Nov 15 17:55:16 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 15 Nov 2009 18:55:16 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B003189.4050000@erols.com> References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> <4B003189.4050000@erols.com> Message-ID: <4B004084.5060101@rubidium.dyndns.org> Chuck Harris wrote: > I guess the point you folks aren't getting is you can make a very > effective local GPS jammer that runs off of a 9V transistor radio battery, > and will last for several weeks. It can be done for a total cost of > a few bucks per jammer.... search the web, the designs are out there. We've known about it for years. > Toss the GPS jammers indiscriminately around the landscape, and you put > GPS out of business for a very low cost. Exactly. You can manufacture hundreds of them and disperse them around. Finding one of those is easy. Having many tens of them around makes it harder. Even if you find several of them, it will take the battery-time for the attack to go away completly. The strategy for such an attack and the strategy to deal with such an attack is a bit different. A military receiver has about 40 dB better suppression just from the coding gain alone (30 dB for C/A and 70 dB for P(Y) if my memory serves me right). A number of other concerns also needs to be dealt with naturally, For obvious reasons alot of effort has been spent on covering this field, and if you are looking, there is alot of material out there. The trouble is that civilian infrastructure does not have the countermeasures at the disposal to the military (US or allied forces). If the civilian infrastructure was limited to a few handfull sites, the modern keying receivers intended for civilian usage would solve part of the problem, but there is a limit to how widely dispersed such receivers can be and also there is such a wide usage. Even lacking such counter-measures, the ability to just detect and warn about lacking reception conditions is less than acceptable in many systems. This details prohibits effective use of other reasnoble countermeasures. Let's recall that interference also can be of non-intentional sort. Also, the huge use of GPS makes it a target for a certain operation, while unintentional targets may also suffer. The trouble is that GPS receivers works too well. Install and forget. Awareness of risk or even the ability to identify what sub-systems even depend on it is limited. Cheers, Magnus From phk at phk.freebsd.dk Sun Nov 15 17:59:34 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 17:59:34 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 10:26:56 MST." <11603302.1258306016911.JavaMail.root@elwamui-hound.atl.sa.earthlink.net> Message-ID: <50362.1258307974@critter.freebsd.dk> In message <11603302.1258306016911.JavaMail.root at elwamui-hound.atl.sa.earthlink .net>, "Richard W. Solomon" writes: >After reading all the responses on this thread, all I can think >of is the numerous ideas you folks have given some whackjob out >there. I don't think you are up to date, all the whack-jobs have GPS jammers already. The first one was documented along with schematics and all in 2600 magazine 15 years ago or so... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From jfor at quik.com Sun Nov 15 18:00:21 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 10:00:21 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <611953893-1258307149-cardhu_decombobulator_blackberry.rim.net-6730663 55-@bda224.bisx.prod.on.blackberry> References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> <4B003189.4050000@erols.com><1103.12.6.201.222.1258305792.squirrel@popacctsnew.quik.com> <611953893-1258307149-cardhu_decombobulator_blackberry.rim.net-673066355-@bda224.bisx.prod.on.blackberry> Message-ID: <1135.12.6.201.222.1258308021.squirrel@popacctsnew.quik.com> How about in the area surrounding a major airport that has frequent low visibility? It is not necessary to jam GPS 100% 24/7. Just enough to cause real concern about it's reliability would do huge damage. How many missiles would be fired by Predator drones if 5 or 10% went wonky and did big colateral damage? -John =============== > Enough for what? To bug the heck out of a citizen suddenly unable to find > his way to the movie theater? > > Weapon systems and aircraft navigation are unlikely to be affected by > such a simple device on the ground, even if deployed in large quantity. > Most of the stuff that really needs GPS has decent antennas that look up, > not down. > > Didier > > ------------------------ Sent from my BlackBerry Wireless thingy while I > do other things... > > -----Original Message----- > From: "J. Forster" > Date: Sun, 15 Nov 2009 09:23:12 > To: Discussion of precise time and frequency > measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator > accuracy) > > Thanks Chuck, > > My point EXACTLY. > > 1. It's well within the capability of dozens of countries or organizations > or even individuals. > > 2. They are trivial to distribute widely, and could be piggy-backed onto > other things. > > 3. Given enough of them with random on-off cycles, you'd force a giant > game of Whak-A-Mole. > > A guy in his basement could easily build 100 in a week given a design and > PCB layout. In another week he could scatter them all over a city, even if > travelling by bus. The whole operation would cost under a few thousand > dollars. > > Furthermore, it would not be needed to kill all the GPS in an area, all > the time. Making it unreliable would likely be enough. > > FWIW, > -John > > ================== > > > >> I guess the point you folks aren't getting is you can make a very >> effective local GPS jammer that runs off of a 9V transistor radio >> battery, >> and will last for several weeks. It can be done for a total cost of >> a few bucks per jammer.... search the web, the designs are out there. >> >> Toss the GPS jammers indiscriminately around the landscape, and you put >> GPS out of business for a very low cost. >> >> -Chuck Harris >> >> Mike Monett wrote: >>> >>> It should be easy to locate a jammer. Go to the area where the GPS >>> signal is being jammed. Drive in some direction until the signal is >>> regained. Repeat to find three locations where the signal is lost. >>> >>> Three points define a circle. The diameter tells the strength of the >>> jamming signal. The center defines the location. >>> >>> Once you are near the center, ordinary DF techniques should quickly >>> identify the source. >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From phk at phk.freebsd.dk Sun Nov 15 18:08:30 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 18:08:30 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 18:55:16 +0100." <4B004084.5060101@rubidium.dyndns.org> Message-ID: <50438.1258308510@critter.freebsd.dk> In message <4B004084.5060101 at rubidium.dyndns.org>, Magnus Danielson writes: >Chuck Harris wrote: >The trouble is that civilian infrastructure [...] That's actually not the biggest problem, the biggest problem is access. If you put a jammer at the top of a tall building (by RC helicopter ?) getting up there to pick it up is non trivial for the people hunting it, they may need court orders to get access to service stairs etc. Strictly speaking here in Denmark, the police would not have authority to kick in a door to stop a GPS jammer, until the PT&T has found it a spectrum violation, warned the owner of the premises, possibly in writing, if it is a rental building. It is not obvious that a signal strong enough to jam GPS would necessarily be found to be a spectrum violation in the first place. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From jfor at quik.com Sun Nov 15 18:07:52 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 10:07:52 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B004084.5060101@rubidium.dyndns.org> References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> <4B003189.4050000@erols.com> <4B004084.5060101@rubidium.dyndns.org> Message-ID: <1143.12.6.201.222.1258308472.squirrel@popacctsnew.quik.com> > Chuck Harris wrote: >> I guess the point you folks aren't getting is you can make a very >> effective local GPS jammer that runs off of a 9V transistor radio >> battery, >> and will last for several weeks. It can be done for a total cost of >> a few bucks per jammer.... search the web, the designs are out there. > > We've known about it for years. > >> Toss the GPS jammers indiscriminately around the landscape, and you put >> GPS out of business for a very low cost. > > Exactly. You can manufacture hundreds of them and disperse them around. > Finding one of those is easy. Having many tens of them around makes it > harder. Even if you find several of them, it will take the battery-time > for the attack to go away completly. The strategy for such an attack and > the strategy to deal with such an attack is a bit different. Not so. You can easily buy a 1F or more capacitor. Take a small box, like a juice box, put a few solar cells on it and a 1F cap and jammer with a pseudo random on-off timer inside and deploy. Bingo... a headache for years. -John From phk at phk.freebsd.dk Sun Nov 15 18:38:10 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 18:38:10 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 10:00:21 PST." <1135.12.6.201.222.1258308021.squirrel@popacctsnew.quik.com> Message-ID: <50528.1258310290@critter.freebsd.dk> In message <1135.12.6.201.222.1258308021.squirrel at popacctsnew.quik.com>, "J. Fo rster" writes: >How about in the area surrounding a major airport that has frequent low >visibility? Airports are different, most airports are allowed to do "whatever it takes" to eliminate interference which is a threat to aviation. They also have the necessary kit to find and identify the jamming signals. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From bg at lysator.liu.se Sun Nov 15 19:19:26 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 15 Nov 2009 20:19:26 +0100 (CET) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <50528.1258310290@critter.freebsd.dk> References: <50528.1258310290@critter.freebsd.dk> Message-ID: <49937.87.227.52.225.1258312766.squirrel@webmail.lysator.liu.se> >>How about in the area surrounding a major airport that has frequent low >>visibility? > > Airports are different, most airports are allowed to do "whatever > it takes" to eliminate interference which is a threat to aviation. > > They also have the necessary kit to find and identify the jamming > signals. > Poul-Henning Then look at the weather forecast, get a supply of weather ballons and release at a random shedule, from a wind direction chosen point. Your jammers now have a good vehicle, to be above the receiver antenna. Very hard to track and take out... I guess the airport soon would make sure non-GPS navaids are well supported. -- Bj?rn From phk at phk.freebsd.dk Sun Nov 15 19:23:42 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 19:23:42 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 20:19:26 +0100." <49937.87.227.52.225.1258312766.squirrel@webmail.lysator.liu.se> Message-ID: <50928.1258313022@critter.freebsd.dk> In message <49937.87.227.52.225.1258312766.squirrel at webmail.lysator.liu.se>, bg @lysator.liu.se writes: >Then look at the weather forecast, get a supply of weather ballons and >release at a random shedule, from a wind direction chosen point. Your >jammers now have a good vehicle, to be above the receiver antenna. Very >hard to track and take out... I guess the airport soon would make sure >non-GPS navaids are well supported. I'm not saying that GPS isn't easy jam-able, I'm saying airports are hard targets for it. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From msa at latt.net Sun Nov 15 19:31:26 2009 From: msa at latt.net (Majdi S. Abbas) Date: Sun, 15 Nov 2009 12:31:26 -0700 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> Message-ID: <20091115193126.GB5237@puck.nether.net> On Sun, Nov 15, 2009 at 11:37:11AM -0500, Mike Monett wrote: > It should be easy to locate a jammer. Go to the area where the GPS > signal is being jammed. Drive in some direction until the signal is > regained. Repeat to find three locations where the signal is lost. > > Three points define a circle. The diameter tells the strength of the > jamming signal. The center defines the location. And if the jammer is attached to, saY a radiosonde balloon or other light aircraft and the footprint covers most of the US? Stop thinking terrestrially. 73, Majdi, N0RMZ From phk at phk.freebsd.dk Sun Nov 15 19:41:07 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 19:41:07 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 12:31:26 MST." <20091115193126.GB5237@puck.nether.net> Message-ID: <50998.1258314067@critter.freebsd.dk> In message <20091115193126.GB5237 at puck.nether.net>, "Majdi S. Abbas" writes: >On Sun, Nov 15, 2009 at 11:37:11AM -0500, Mike Monett wrote: > And if the jammer is attached to, saY a radiosonde balloon or >other light aircraft and the footprint covers most of the US? It doesn't. Hint: http://blogs.techrepublic.com.com/geekend/?p=372 -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From didier at cox.net Sun Nov 15 20:01:25 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 20:01:25 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <20091115193126.GB5237@puck.nether.net> References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com><20091115193126.GB5237@puck.nether.net> Message-ID: <906122735-1258315279-cardhu_decombobulator_blackberry.rim.net-2013333181-@bda224.bisx.prod.on.blackberry> That would be extremely effective, and over a broad area, but then they will probably not run for weeks. Didier ------------------------ Sent from my BlackBerry Wireless thingy while I do other things... -----Original Message----- From: "Majdi S. Abbas" Date: Sun, 15 Nov 2009 12:31:26 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) On Sun, Nov 15, 2009 at 11:37:11AM -0500, Mike Monett wrote: > It should be easy to locate a jammer. Go to the area where the GPS > signal is being jammed. Drive in some direction until the signal is > regained. Repeat to find three locations where the signal is lost. > > Three points define a circle. The diameter tells the strength of the > jamming signal. The center defines the location. And if the jammer is attached to, saY a radiosonde balloon or other light aircraft and the footprint covers most of the US? Stop thinking terrestrially. 73, Majdi, N0RMZ _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Sun Nov 15 20:48:41 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 15 Nov 2009 21:48:41 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <611953893-1258307149-cardhu_decombobulator_blackberry.rim.net-673066355-@bda224.bisx.prod.on.blackberry> References: <2812.12.6.201.202.1258244533.squirrel@popacctsnew.quik.com> <4B003189.4050000@erols.com><1103.12.6.201.222.1258305792.squirrel@popacctsnew.quik.com> <611953893-1258307149-cardhu_decombobulator_blackberry.rim.net-673066355-@bda224.bisx.prod.on.blackberry> Message-ID: <4B006929.3010809@rubidium.dyndns.org> Didier Juges wrote: > Enough for what? To bug the heck out of a citizen suddenly unable to find his way to the movie theater? > > Weapon systems and aircraft navigation are unlikely to be affected by such a simple device on the ground, even if deployed in large quantity. Most of the stuff that really needs GPS has decent antennas that look up, not down. They are affected, it is well covered, but the difference is the distance from the jammer until affected. It's a fairly well-understood problem and the difference between civilian and military receivers lies in signals, keying for access, bootstrapping and testing and counter-measures such as IMU. Cheers, Magnus From phk at phk.freebsd.dk Sun Nov 15 20:54:47 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 20:54:47 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 21:48:41 +0100." <4B006929.3010809@rubidium.dyndns.org> Message-ID: <51317.1258318487@critter.freebsd.dk> In message <4B006929.3010809 at rubidium.dyndns.org>, Magnus Danielson writes: >distance from the jammer until affected. It's a fairly well-understood >problem and the difference between civilian and military receivers lies >in signals, keying for access, bootstrapping and testing and >counter-measures such as IMU. Not to mention clocks: The more stable clock a GPS receiver has, the harder it is to jam it, because the "unspread bandwidth" can be much tighter. Somebody showed a specially tuned GPS receiver, clocked from Cs to be pretty much invulnerable to "randomised" jamming. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From cfharris at erols.com Sun Nov 15 21:01:45 2009 From: cfharris at erols.com (Chuck Harris) Date: Sun, 15 Nov 2009 16:01:45 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <11603302.1258306016911.JavaMail.root@elwamui-hound.atl.sa.earthlink.net> References: <11603302.1258306016911.JavaMail.root@elwamui-hound.atl.sa.earthlink.net> Message-ID: <4B006C39.1050005@erols.com> Given that I learned the techniques from a bunch of wack-jobs, I don't think I have upped the learning curve much. -Chuck Richard W. Solomon wrote: > After reading all the responses on this thread, all I can think > of is the numerous ideas you folks have given some whackjob out > there. > > Keep up the good work. > > 73, Dick, W1KSZ From robert8rpi at yahoo.co.uk Sun Nov 15 21:14:23 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Sun, 15 Nov 2009 21:14:23 +0000 (GMT) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <4B006929.3010809@rubidium.dyndns.org> Message-ID: <264275.47943.qm@web27105.mail.ukl.yahoo.com> There is also the use of directional antennas. Difficult to put your jammer between the Rx and the sat.? --- On Sun, 15/11/09, Magnus Danielson wrote: From: Magnus Danielson Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) To: didier at cox.net, "Discussion of precise time and frequency measurement" Date: Sunday, 15 November, 2009, 20:48 Didier Juges wrote: > Enough for what? To bug the heck out of a citizen suddenly unable to find his way to the movie theater? > > Weapon systems and aircraft navigation? are unlikely to be affected by such a simple device on the ground, even if deployed in large quantity. Most of the stuff that really needs GPS has decent antennas that look up, not down. They are affected, it is well covered, but the difference is the distance from the jammer until affected. It's a fairly well-understood problem and the difference between civilian and military receivers lies in signals, keying for access, bootstrapping and testing and counter-measures such as IMU. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Sun Nov 15 21:58:05 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 15 Nov 2009 22:58:05 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <264275.47943.qm@web27105.mail.ukl.yahoo.com> References: <264275.47943.qm@web27105.mail.ukl.yahoo.com> Message-ID: <4B00796D.6030300@rubidium.dyndns.org> Robert Atkinson wrote: > There is also the use of directional antennas. Difficult to put your jammer between the Rx and the sat. Actually, that doesn't help much in a multiple jammer scenario. The directional antenna needs to have their directional lobes towards each sat being tracked. If you try put the nulls towards the jammers then you need to have a fair knowledge of where it is. If you direct the loop, the side-loobs needs to be sufficiently suppressed. A single jammer and a fair idea of the heading will work, but it becomes complex and in the end you need more and more antennas to handle more jammers. Also, recall that you need good dynamics on all the antenna frontends. You can handle it, but it isn't compact and neat as you are used to. Directional antennas gives some additional gain, but to a limit. It comes at a price. A rather high price compared to many other countermeasures. It only fit some few uses. Cheers, Magnus From brahn at woh.rr.com Sun Nov 15 22:26:53 2009 From: brahn at woh.rr.com (Bruce Rahn) Date: Sun, 15 Nov 2009 17:26:53 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <4B00796D.6030300@rubidium.dyndns.org> References: <264275.47943.qm@web27105.mail.ukl.yahoo.com> <4B00796D.6030300@rubidium.dyndns.org> Message-ID: <4B00802D.70101@woh.rr.com> Magnus Danielson wrote: > The directional antenna needs to have their directional lobes towards > each sat being tracked. If you try put the nulls towards the jammers > then you need to have a fair knowledge of where it is. If you direct > the loop, the side-loobs needs to be sufficiently suppressed. A single > jammer and a fair idea of the heading will work, but it becomes > complex and in the end you need more and more antennas to handle more > jammers. Ah...you really don't need any a prori knowledge of the location of a jammer. A little reading on adaptive antenna technology as applied to GPS will throw light on my comment and is also some interesting reading. This would be a starting point: http://www.raytheon.com/businesses/stellent/groups/sas/documents/content/cms04_022900.pdf Bruce, WB9ANQ -- Bruce Rahn Wisdom has two parts: 1. having a lot to say; and 2. not saying it! From xde-l2g3 at myamail.com Sun Nov 15 23:18:38 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Sun, 15 Nov 2009 18:18:38 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) References: <4B003189.4050000@erols.com> Message-ID: Chuck Harris wrote: > I guess the point you folks aren't getting is you can make a very > effective local GPS jammer that runs off of a 9V transistor radio > battery, and will last for several weeks. It can be done for a > total cost of a few bucks per jammer.... search the web, the > designs are out there. > Toss the GPS jammers indiscriminately around the landscape, and > you put GPS out of business for a very low cost. >-Chuck Harris I'm not so sure that would be very effective. A typical 9v alkaline contains about 900 milliamp/hours at low current drain. Two weeks is 24 * 7 * 2 = 336 hrs. Assuming 100% efficiency, the battery would supply 0.9 / 336 = 0.00267A, or 0.024 watt, not including the drop in voltage after the first few dozen hours. There are quite a few commercial jammers designed specifically to jam GPS signals. These are extremely illegal, but they do give some idea of the range that could be expected. Below is a list of the specified range and power. I calculate the highest ratio to get the meters per watt. GMW12 Cellular & GPS L1 Jammer Block cellular signals and GPS L1 system in the same time Jamming Range : Average 40 meters radius Output Power : Total 6.5 Watt ratio : 40/6.5 = 6.15 meters/watt KYG0014 Fixed Jammer Output Power : 2000mw Jamming Range : 15~20 meters ratio : 20/2 = 10 meters/watt KYG0017 Powerful GPS signal jammer Output power : 25W Range : radius 100-300meters ratio : 300 / 25 = 12 meters/watt KYG0013 Car GPS jammer Output power : 800mW Range : radius 10-15 meters ratio : 15 / 0.8 = 8.75 meters/watt KYP0050 Handheld GPS/GSM signal Jammer / blocker output power : 300mw jamming range : 2~10 meters ratio : 10 / 0.3 = 33.33 meters/watt The average ratio is: (33.33 + 8.75 + 8.75 + 12 + 10 + 6.15) / 6 = 13.16 meters/watt. The highest claimed performance is the KYP0050, with 33 meters/watt. Assuming the 9V battery jammer has 100% RF efficiency and equal ratio, the jamming range would be 33.33 * 0.024 = 0.799 meters or about 2.62 feet. However, a jammer would require crystal control to stay on frequency. There are no crystals for L1, so a multiplier would be needed. The actual power output would be much lower, so the range would be much less. Another example, a 1500mAh rechargable pocket jammer has a 5 meter range, and only lasts 2~3 hrs: GMT04 Pocket GPS Jammer Jaming Range : Average 5 meters radius Current & Voltage : 200mA DC12V / AC120~140V Battery : 1,500mAh battery life 2~3 hours, recharge needs 3~4 hours So a 9V transistor radio battery jammer doesn't seem like it would present much of a danger. Mike Monett From cfharris at erols.com Sun Nov 15 23:31:07 2009 From: cfharris at erols.com (Chuck Harris) Date: Sun, 15 Nov 2009 18:31:07 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4B003189.4050000@erols.com> Message-ID: <4B008F3B.8030300@erols.com> What makes you think it needs to be CW, and cannot be pulsed and chirped? All it has to do is confuse the receiver enough so that you can't trust its readings. -Chuck Mike Monett wrote: > Chuck Harris wrote: > > > I guess the point you folks aren't getting is you can make a very > > effective local GPS jammer that runs off of a 9V transistor radio > > battery, and will last for several weeks. It can be done for a > > total cost of a few bucks per jammer.... search the web, the > > designs are out there. > > > Toss the GPS jammers indiscriminately around the landscape, and > > you put GPS out of business for a very low cost. > > >-Chuck Harris > > I'm not so sure that would be very effective. A typical 9v alkaline > contains about 900 milliamp/hours at low current drain. > > Two weeks is 24 * 7 * 2 = 336 hrs. Assuming 100% efficiency, the > battery would supply 0.9 / 336 = 0.00267A, or 0.024 watt, not > including the drop in voltage after the first few dozen hours. > > There are quite a few commercial jammers designed specifically to > jam GPS signals. These are extremely illegal, but they do give some > idea of the range that could be expected. > > Below is a list of the specified range and power. I calculate the > highest ratio to get the meters per watt. > > GMW12 Cellular & GPS L1 Jammer > > Block cellular signals and GPS L1 system in the same time > > Jamming Range : Average 40 meters radius > Output Power : Total 6.5 Watt > > ratio : 40/6.5 = 6.15 meters/watt > > > > KYG0014 Fixed Jammer > > Output Power : 2000mw > Jamming Range : 15~20 meters > > ratio : 20/2 = 10 meters/watt > > > > KYG0017 Powerful GPS signal jammer > > Output power : 25W > Range : radius 100-300meters > > ratio : 300 / 25 = 12 meters/watt > > > > > KYG0013 Car GPS jammer > > Output power : 800mW > Range : radius 10-15 meters > > ratio : 15 / 0.8 = 8.75 meters/watt > > > > KYP0050 Handheld GPS/GSM signal Jammer / blocker > > output power : 300mw > jamming range : 2~10 meters > > ratio : 10 / 0.3 = 33.33 meters/watt > > > > > The average ratio is: > > (33.33 + 8.75 + 8.75 + 12 + 10 + 6.15) / 6 = 13.16 meters/watt. > > The highest claimed performance is the KYP0050, with 33 meters/watt. > > Assuming the 9V battery jammer has 100% RF efficiency and equal > ratio, the jamming range would be 33.33 * 0.024 = 0.799 meters or > about 2.62 feet. > > However, a jammer would require crystal control to stay on > frequency. There are no crystals for L1, so a multiplier would be > needed. The actual power output would be much lower, so the range > would be much less. > > Another example, a 1500mAh rechargable pocket jammer has a 5 meter > range, and only lasts 2~3 hrs: > > GMT04 Pocket GPS Jammer > > Jaming Range : Average 5 meters radius > Current & Voltage : 200mA DC12V / AC120~140V > Battery : 1,500mAh > > battery life 2~3 hours, recharge needs 3~4 hours > > > > So a 9V transistor radio battery jammer doesn't seem like it would > present much of a danger. > > Mike Monett > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From fortime at bellsouth.net Sun Nov 15 23:36:17 2009 From: fortime at bellsouth.net (phil) Date: Sun, 15 Nov 2009 18:36:17 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Referenceoscillatoraccuracy) References: <264275.47943.qm@web27105.mail.ukl.yahoo.com> Message-ID: <97E3E120718743759311AC25538C4FA6@devoffice> Didier Juges wrote: > Enough for what? To bug the heck out of a citizen suddenly unable to find > his way to the movie theater? > > Weapon systems and aircraft navigation are unlikely to be affected by such > a simple device on the ground, even if deployed in large quantity. Most of > the stuff that really needs GPS has decent antennas that look up, not > down. They are affected, it is well covered, but the difference is the distance from the jammer until affected. It's a fairly well-understood problem and the difference between civilian and military receivers lies in signals, keying for access, bootstrapping and testing and counter-measures such as IMU. Cheers, Magnus Possibly the two largest threats are being overlooked in this discussion. The US, Russia, and now China has numerous, possibly in the hundreds of clandestine truck sized satellites. Allot thought to weigh in at 8 to 10 thousand pounds and some such as launched by the space shuttle to weigh in at 50,000 pounds up there now. Are they for communications, super-duper eyeballs, overgrown pea-shooters/laser guns, jammers, another positioning technology, or all of the above? Perhaps the ability to take out the various gps and other satellite systems exists now with the push of a button. Should systems go down under those circumstances, finding the nearest Starbucks using gps may be the least of our worries. Second and perhaps the real threat is a series of unprecedented solar storms or other unknown space based threats. That could conceivably render most of the satellites useless. I would think that ground based backup of all satellite systems would be mandatory. Phil From magnus at rubidium.dyndns.org Sun Nov 15 23:40:27 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 00:40:27 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <4B00802D.70101@woh.rr.com> References: <264275.47943.qm@web27105.mail.ukl.yahoo.com> <4B00796D.6030300@rubidium.dyndns.org> <4B00802D.70101@woh.rr.com> Message-ID: <4B00916B.3080702@rubidium.dyndns.org> Bruce Rahn wrote: > Magnus Danielson wrote: >> The directional antenna needs to have their directional lobes towards >> each sat being tracked. If you try put the nulls towards the jammers >> then you need to have a fair knowledge of where it is. If you direct >> the loop, the side-loobs needs to be sufficiently suppressed. A single >> jammer and a fair idea of the heading will work, but it becomes >> complex and in the end you need more and more antennas to handle more >> jammers. > Ah...you really don't need any a prori knowledge of the location of a > jammer. > A little reading on adaptive antenna technology as applied to GPS will > throw light on my comment and is also some interesting reading. This > would be a starting point: > http://www.raytheon.com/businesses/stellent/groups/sas/documents/content/cms04_022900.pdf You can use different strategies yes. I was unclear on that. Either you know the direction and then you can optimize for that or you just use the power of multiple antennas to create individual lobes for each receiver channels. You can balance lobe-gain to sat to that of the offender for best suppression. Setting lobes for each sat does not need the direction info on the jammer. That link does not provide as much information as a number of online articles on directional antennas giving much more detail. Cheers, Magnus From magnus at rubidium.dyndns.org Sun Nov 15 23:46:17 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 00:46:17 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B008F3B.8030300@erols.com> References: <4B003189.4050000@erols.com> <4B008F3B.8030300@erols.com> Message-ID: <4B0092C9.1030400@rubidium.dyndns.org> Chuck, Chuck Harris wrote: > What makes you think it needs to be CW, and cannot be pulsed and > chirped? May I roll in a noise jammer into the debate? > All it has to do is confuse the receiver enough so that you can't > trust its readings. Depends on the goal. For some strategies, blackout is the goal, for some getting the readings go haywire every once in a while suffice. Cheers, Magnus From phk at phk.freebsd.dk Sun Nov 15 23:52:33 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 15 Nov 2009 23:52:33 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: Your message of "Sun, 15 Nov 2009 22:58:05 +0100." <4B00796D.6030300@rubidium.dyndns.org> Message-ID: <52055.1258329153@critter.freebsd.dk> In message <4B00796D.6030300 at rubidium.dyndns.org>, Magnus Danielson writes: >Robert Atkinson wrote: >The directional antenna needs to have their directional lobes towards >each sat being tracked. If you try put the nulls towards the jammers >then you need to have a fair knowledge of where it is. The phased array antennas does not operate in CW mode. Once you have sat lock, you can operate the antennas in time-gate mode, and only sampling each bird in a very narrow time window & frequency band around the code-sign-change event and doppler frequency. That still does not reduce your antenna to a single beam, certainly not if you only have 7 elements in 2D config, but for any moving platform, that will make the 'sidelopes' swinging all over the place, thus attenuating the jammer but not the intended bird. And yes, this is not simple, but 97W ought to do it. For a fixed location receiver, Pos-Hold mode is pretty efficient, in particular if running of a known stable clock. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From cfharris at erols.com Mon Nov 16 00:11:14 2009 From: cfharris at erols.com (Chuck Harris) Date: Sun, 15 Nov 2009 19:11:14 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B0092C9.1030400@rubidium.dyndns.org> References: <4B003189.4050000@erols.com> <4B008F3B.8030300@erols.com> <4B0092C9.1030400@rubidium.dyndns.org> Message-ID: <4B0098A2.4030303@erols.com> Magnus Danielson wrote: > Chuck, > > Chuck Harris wrote: >> What makes you think it needs to be CW, and cannot be pulsed and >> chirped? > > May I roll in a noise jammer into the debate? Absolutely! They can be extremely power efficient. Raise the noise floor in the vicinity of the receiver, and it is all done. Probably the easiest solution would be to take a PN source and use it to drive a pulser that pulses a chirp oscillator. If you are feeling really polite, you could put a bandpass filter on the thing to protect other services. >> All it has to do is confuse the receiver enough so that you can't >> trust its readings. > > Depends on the goal. For some strategies, blackout is the goal, for some > getting the readings go haywire every once in a while suffice. Agreed! My 9V battery suggestion was for a localized blackout device. You only have to make the receiver question each satellite's signal often enough for it to rule it out. No way is CW necessary, or even desirable. As John suggested, someone (say the Chinese) could put these things in battery operated stuffed animals, and set them up to jam a little bit now and then. After Xmas, the GPS landscape would be littered with these little stealth jammers, and willing supplicants to replace their batteries. -Chuck From hmurray at megapathdsl.net Mon Nov 16 00:13:18 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sun, 15 Nov 2009 16:13:18 -0800 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Message from Chuck Harris of "Sun, 15 Nov 2009 18:31:07 EST." <4B008F3B.8030300@erols.com> Message-ID: <20091116001319.0BAC3BCFC@ip-64-139-1-69.sjc.megapath.net> cfharris at erols.com said: > What makes you think it needs to be CW, and cannot be pulsed and > chirped? > All it has to do is confuse the receiver enough so that you can't > trust its readings. Why is pulse or chirp likely to be more confusing per W of jamming power? I thought the GPS signal was spread spectrum so I wouldn't expect any simple pulse or chirp to be better at jamming than noise over the appropriate bandwidth. If you know the spread spectrum details (which must be public or the receiver can't listen to the signal), then you might be able to mimic a satellite signal. I think that needs the time, so you probably need to listen to the signal you are jamming. Am I on the right track? Is there a trick I'm missing? (If so, how complicated is it?) -- These are my opinions, not necessarily my employer's. I hate spam. From bruce.griffiths at xtra.co.nz Mon Nov 16 00:25:38 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 16 Nov 2009 13:25:38 +1300 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4B003189.4050000@erols.com> Message-ID: <4B009C02.3000309@xtra.co.nz> Mike Instead of relying on the dubious claims of those marketing an extremely inefficient jammer it would be better to actually do some simple calculations. Typical commercial receivers stop tracking with a Jam to signal ratio of not more than 60dB or so: http://www.gpsworld.com/gps/jamming-gps-778 The input signal level at the receiver input is around -160dBW. A 1W ERP source with an isotropic hemispheric radiation pattern will exceed the the required jamming signal strength for distances less than several tens of kilometers. This estimate is consistent with the fact that LO parasitic radiation from TV systems on boats have been known to jam GPS for distances of several kilometers. Bruce Mike Monett wrote: > Chuck Harris wrote: > > > I guess the point you folks aren't getting is you can make a very > > effective local GPS jammer that runs off of a 9V transistor radio > > battery, and will last for several weeks. It can be done for a > > total cost of a few bucks per jammer.... search the web, the > > designs are out there. > > > Toss the GPS jammers indiscriminately around the landscape, and > > you put GPS out of business for a very low cost. > > >-Chuck Harris > > I'm not so sure that would be very effective. A typical 9v alkaline > contains about 900 milliamp/hours at low current drain. > > Two weeks is 24 * 7 * 2 = 336 hrs. Assuming 100% efficiency, the > battery would supply 0.9 / 336 = 0.00267A, or 0.024 watt, not > including the drop in voltage after the first few dozen hours. > > There are quite a few commercial jammers designed specifically to > jam GPS signals. These are extremely illegal, but they do give some > idea of the range that could be expected. > > Below is a list of the specified range and power. I calculate the > highest ratio to get the meters per watt. > > GMW12 Cellular& GPS L1 Jammer > > Block cellular signals and GPS L1 system in the same time > > Jamming Range : Average 40 meters radius > Output Power : Total 6.5 Watt > > ratio : 40/6.5 = 6.15 meters/watt > > > > KYG0014 Fixed Jammer > > Output Power : 2000mw > Jamming Range : 15~20 meters > > ratio : 20/2 = 10 meters/watt > > > > KYG0017 Powerful GPS signal jammer > > Output power : 25W > Range : radius 100-300meters > > ratio : 300 / 25 = 12 meters/watt > > > > > KYG0013 Car GPS jammer > > Output power : 800mW > Range : radius 10-15 meters > > ratio : 15 / 0.8 = 8.75 meters/watt > > > > KYP0050 Handheld GPS/GSM signal Jammer / blocker > > output power : 300mw > jamming range : 2~10 meters > > ratio : 10 / 0.3 = 33.33 meters/watt > > > > > The average ratio is: > > (33.33 + 8.75 + 8.75 + 12 + 10 + 6.15) / 6 = 13.16 meters/watt. > > The highest claimed performance is the KYP0050, with 33 meters/watt. > > Assuming the 9V battery jammer has 100% RF efficiency and equal > ratio, the jamming range would be 33.33 * 0.024 = 0.799 meters or > about 2.62 feet. > > However, a jammer would require crystal control to stay on > frequency. There are no crystals for L1, so a multiplier would be > needed. The actual power output would be much lower, so the range > would be much less. > > Another example, a 1500mAh rechargable pocket jammer has a 5 meter > range, and only lasts 2~3 hrs: > > GMT04 Pocket GPS Jammer > > Jaming Range : Average 5 meters radius > Current& Voltage : 200mA DC12V / AC120~140V > Battery : 1,500mAh > > battery life 2~3 hours, recharge needs 3~4 hours > > > > So a 9V transistor radio battery jammer doesn't seem like it would > present much of a danger. > > Mike Monett > > From hmurray at megapathdsl.net Mon Nov 16 00:30:06 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sun, 15 Nov 2009 16:30:06 -0800 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Message from "Mike Monett" of "Sun, 15 Nov 2009 18:18:38 EST." Message-ID: <20091116003007.1F5B0BCFC@ip-64-139-1-69.sjc.megapath.net> > Jamming Range : Average 40 meters radius > Output Power : Total 6.5 Watt > ratio : 40/6.5 = 6.15 meters/watt Isn't received power 1/R-squared? I think those calculations should be radius-squared/watts I find it interesting that the products designed as jammers have ranges of "only" a few 10s of meters while a recent message here said 1/2 mile from a digital-radio link that was transmitting on 315 MHz. (aka designed for something else rather than as a jammer) Similarly, the Monterey Bay jammer wasn't trying to be a jammer, and it wiped out a huge area. -- These are my opinions, not necessarily my employer's. I hate spam. From jfor at quik.com Mon Nov 16 00:28:00 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 16:28:00 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B0098A2.4030303@erols.com> References: <4B003189.4050000@erols.com> <4B008F3B.8030300@erols.com> <4B0092C9.1030400@rubidium.dyndns.org> <4B0098A2.4030303@erols.com> Message-ID: <2294.12.6.201.222.1258331280.squirrel@popacctsnew.quik.com> Or even into MP3 players, iPods, laptops, or cell phones. Then they'd wander all over the place too. With the latter two hosts, they could even be controlled remotely and even be fairly powerful. Would you notice having to recharge your battery a bit more often? -John =========== > Magnus Danielson wrote: >> Chuck, >> >> Chuck Harris wrote: >>> What makes you think it needs to be CW, and cannot be pulsed and >>> chirped? >> >> May I roll in a noise jammer into the debate? > > Absolutely! They can be extremely power efficient. Raise the noise > floor in the vicinity of the receiver, and it is all done. > > Probably the easiest solution would be to take a PN source and use it > to drive a pulser that pulses a chirp oscillator. If you are feeling > really polite, you could put a bandpass filter on the thing to protect > other services. > >>> All it has to do is confuse the receiver enough so that you can't >>> trust its readings. >> >> Depends on the goal. For some strategies, blackout is the goal, for some >> getting the readings go haywire every once in a while suffice. > > Agreed! > > My 9V battery suggestion was for a localized blackout device. You only > have to make the receiver question each satellite's signal often enough > for it to rule it out. No way is CW necessary, or even desirable. > > As John suggested, someone (say the Chinese) could put these things in > battery operated stuffed animals, and set them up to jam a little bit > now and then. After Xmas, the GPS landscape would be littered with these > little stealth jammers, and willing supplicants to replace their > batteries. > > -Chuck > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From frledda at verizon.net Mon Nov 16 00:37:08 2009 From: frledda at verizon.net (Francesco Ledda) Date: Sun, 15 Nov 2009 18:37:08 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2294.12.6.201.222.1258331280.squirrel@popacctsnew.quik.com> Message-ID: Considering that the GPS antenna in aircrafts is mounted on top of fuselage, and that its radiation pattern is upward, it seems that a ground jammer will have an uphill battle. -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of J. Forster Sent: Sunday, November 15, 2009 6:28 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Or even into MP3 players, iPods, laptops, or cell phones. Then they'd wander all over the place too. With the latter two hosts, they could even be controlled remotely and even be fairly powerful. Would you notice having to recharge your battery a bit more often? -John =========== > Magnus Danielson wrote: >> Chuck, >> >> Chuck Harris wrote: >>> What makes you think it needs to be CW, and cannot be pulsed and >>> chirped? >> >> May I roll in a noise jammer into the debate? > > Absolutely! They can be extremely power efficient. Raise the noise > floor in the vicinity of the receiver, and it is all done. > > Probably the easiest solution would be to take a PN source and use it > to drive a pulser that pulses a chirp oscillator. If you are feeling > really polite, you could put a bandpass filter on the thing to protect > other services. > >>> All it has to do is confuse the receiver enough so that you can't >>> trust its readings. >> >> Depends on the goal. For some strategies, blackout is the goal, for some >> getting the readings go haywire every once in a while suffice. > > Agreed! > > My 9V battery suggestion was for a localized blackout device. You only > have to make the receiver question each satellite's signal often enough > for it to rule it out. No way is CW necessary, or even desirable. > > As John suggested, someone (say the Chinese) could put these things in > battery operated stuffed animals, and set them up to jam a little bit > now and then. After Xmas, the GPS landscape would be littered with these > little stealth jammers, and willing supplicants to replace their > batteries. > > -Chuck > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ From magnus at rubidium.dyndns.org Mon Nov 16 00:39:42 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 01:39:42 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B0098A2.4030303@erols.com> References: <4B003189.4050000@erols.com> <4B008F3B.8030300@erols.com> <4B0092C9.1030400@rubidium.dyndns.org> <4B0098A2.4030303@erols.com> Message-ID: <4B009F4E.5020600@rubidium.dyndns.org> Chuck Harris wrote: > Magnus Danielson wrote: >> Chuck, >> >> Chuck Harris wrote: >>> What makes you think it needs to be CW, and cannot be pulsed and >>> chirped? >> >> May I roll in a noise jammer into the debate? > > Absolutely! They can be extremely power efficient. Raise the noise > floor in the vicinity of the receiver, and it is all done. > > Probably the easiest solution would be to take a PN source and use it > to drive a pulser that pulses a chirp oscillator. If you are feeling > really polite, you could put a bandpass filter on the thing to protect > other services. The schematic out there is a PN source feeding an OCXO and then amplified. Crystal loop to keep fairly centered. More or less the same as personalized phone jammers do. Very simple design. >>> All it has to do is confuse the receiver enough so that you can't >>> trust its readings. >> >> Depends on the goal. For some strategies, blackout is the goal, for >> some getting the readings go haywire every once in a while suffice. > > Agreed! > > My 9V battery suggestion was for a localized blackout device. You only > have to make the receiver question each satellite's signal often enough > for it to rule it out. No way is CW necessary, or even desirable. True. > As John suggested, someone (say the Chinese) could put these things in > battery operated stuffed animals, and set them up to jam a little bit > now and then. After Xmas, the GPS landscape would be littered with these > little stealth jammers, and willing supplicants to replace their batteries. Well, then you have to consider what the potential gain would be from such an attack. I fail to see the upside of that particular scenario. It would draw the attention over to them and in a field I think they rather stay calm about. Their ability to pull it off as such should not be doubted, but their resoning for it. Rather inefficient actually. Cheers, Magnus From jfor at quik.com Mon Nov 16 00:38:14 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 16:38:14 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B009C02.3000309@xtra.co.nz> References: <4B003189.4050000@erols.com> <4B009C02.3000309@xtra.co.nz> Message-ID: <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com> Even 10 KM is pretty useful. If the thing were solar powered with a supercap "battery" it could easly transmit for say 2 minutes per hour w/ significant power. It'd be hard to find if the on times were generated by a multiple fedback CMOS shift register. -John ================ > Mike > > Instead of relying on the dubious claims of those marketing an extremely > inefficient jammer it would be better to actually do some simple > calculations. > > Typical commercial receivers stop tracking with a Jam to signal ratio of > not more than 60dB or so: > http://www.gpsworld.com/gps/jamming-gps-778 > > The input signal level at the receiver input is around -160dBW. > > A 1W ERP source with an isotropic hemispheric radiation pattern will > exceed the the required jamming signal strength for distances less than > several tens of kilometers. > > This estimate is consistent with the fact that LO parasitic radiation > from TV systems on boats have been known to jam GPS for distances of > several kilometers. > > Bruce > > Mike Monett wrote: >> Chuck Harris wrote: >> >> > I guess the point you folks aren't getting is you can make a very >> > effective local GPS jammer that runs off of a 9V transistor radio >> > battery, and will last for several weeks. It can be done for a >> > total cost of a few bucks per jammer.... search the web, the >> > designs are out there. >> >> > Toss the GPS jammers indiscriminately around the landscape, and >> > you put GPS out of business for a very low cost. >> >> >-Chuck Harris >> >> I'm not so sure that would be very effective. A typical 9v alkaline >> contains about 900 milliamp/hours at low current drain. >> >> Two weeks is 24 * 7 * 2 = 336 hrs. Assuming 100% efficiency, the >> battery would supply 0.9 / 336 = 0.00267A, or 0.024 watt, not >> including the drop in voltage after the first few dozen hours. >> >> There are quite a few commercial jammers designed specifically to >> jam GPS signals. These are extremely illegal, but they do give some >> idea of the range that could be expected. >> >> Below is a list of the specified range and power. I calculate the >> highest ratio to get the meters per watt. >> >> GMW12 Cellular& GPS L1 Jammer >> >> Block cellular signals and GPS L1 system in the same time >> >> Jamming Range : Average 40 meters radius >> Output Power : Total 6.5 Watt >> >> ratio : 40/6.5 = 6.15 meters/watt >> >> >> >> KYG0014 Fixed Jammer >> >> Output Power : 2000mw >> Jamming Range : 15~20 meters >> >> ratio : 20/2 = 10 meters/watt >> >> >> >> KYG0017 Powerful GPS signal jammer >> >> Output power : 25W >> Range : radius 100-300meters >> >> ratio : 300 / 25 = 12 meters/watt >> >> >> >> >> KYG0013 Car GPS jammer >> >> Output power : 800mW >> Range : radius 10-15 meters >> >> ratio : 15 / 0.8 = 8.75 meters/watt >> >> >> >> KYP0050 Handheld GPS/GSM signal Jammer / blocker >> >> output power : 300mw >> jamming range : 2~10 meters >> >> ratio : 10 / 0.3 = 33.33 meters/watt >> >> >> >> >> The average ratio is: >> >> (33.33 + 8.75 + 8.75 + 12 + 10 + 6.15) / 6 = 13.16 meters/watt. >> >> The highest claimed performance is the KYP0050, with 33 meters/watt. >> >> Assuming the 9V battery jammer has 100% RF efficiency and equal >> ratio, the jamming range would be 33.33 * 0.024 = 0.799 meters or >> about 2.62 feet. >> >> However, a jammer would require crystal control to stay on >> frequency. There are no crystals for L1, so a multiplier would be >> needed. The actual power output would be much lower, so the range >> would be much less. >> >> Another example, a 1500mAh rechargable pocket jammer has a 5 meter >> range, and only lasts 2~3 hrs: >> >> GMT04 Pocket GPS Jammer >> >> Jaming Range : Average 5 meters radius >> Current& Voltage : 200mA DC12V / AC120~140V >> Battery : 1,500mAh >> >> battery life 2~3 hours, recharge needs 3~4 hours >> >> >> >> So a 9V transistor radio battery jammer doesn't seem like it would >> present much of a danger. >> >> Mike Monett >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From xde-l2g3 at myamail.com Mon Nov 16 00:41:35 2009 From: xde-l2g3 at myamail.com (Mike Monett) Date: Sun, 15 Nov 2009 19:41:35 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) References: <4B008F3B.8030300@erols.com> Message-ID: Chuck Harris wrote: > >What makes you think it needs to be CW, and cannot be pulsed and >chirped? > >All it has to do is confuse the receiver enough so that you can't >trust its readings. > >-Chuck I said nothing about the type of modulation. The equipment I listed is designed specifically to disrupt GPS. Presumably they use whatever modulation method that gives the best results. However, GPS is spread-spectrum, so it inherently rejects noise that is not correlated with the satellite signal. This means effective jamming requires a lot more power than is available from a 9V transistor radio battery, and even then, the range is only a few meters. I made an error in calculating the average range per watt. The original shows 8.75 meters/watt twice: (33.33 + 8.75 + 8.75 + 12 + 10 + 6.15) / 6 = 13.16 meters/watt. It should be (33.33 + 8.75 + 12 + 10 + 6.15) / 5 = 14.046 meters/watt. This does not affect the conclusion, which is it takes a lot more power to disrupt GPS than it first appears. Putting jammers in Christmas toys would accomplish little except to drain the batteries faster. Mike Monett From jfor at quik.com Mon Nov 16 00:51:29 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 16:51:29 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: Message-ID: <2316.12.6.201.222.1258332689.squirrel@popacctsnew.quik.com> See my earlier post. Briefly: Antennas do not have an infinite front-to-back ratio. (<40 dB) The path loss from a surface jammer to a plane (10 miles) is many, many dB less than from plane to bird (15,000 miles). -John ============ > Considering that the GPS antenna in aircrafts is mounted on top of > fuselage, > and that its radiation pattern is upward, it seems that a ground jammer > will > have an uphill battle. > > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of J. Forster > Sent: Sunday, November 15, 2009 6:28 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference > oscillator accuracy) > > > Or even into MP3 players, iPods, laptops, or cell phones. Then they'd > wander all over the place too. With the latter two hosts, they could even > be controlled remotely and even be fairly powerful. Would you notice > having to recharge your battery a bit more often? > > -John > > =========== > > >> Magnus Danielson wrote: >>> Chuck, >>> >>> Chuck Harris wrote: >>>> What makes you think it needs to be CW, and cannot be pulsed and >>>> chirped? >>> >>> May I roll in a noise jammer into the debate? >> >> Absolutely! They can be extremely power efficient. Raise the noise >> floor in the vicinity of the receiver, and it is all done. >> >> Probably the easiest solution would be to take a PN source and use it >> to drive a pulser that pulses a chirp oscillator. If you are feeling >> really polite, you could put a bandpass filter on the thing to protect >> other services. >> >>>> All it has to do is confuse the receiver enough so that you can't >>>> trust its readings. >>> >>> Depends on the goal. For some strategies, blackout is the goal, for >>> some >>> getting the readings go haywire every once in a while suffice. >> >> Agreed! >> >> My 9V battery suggestion was for a localized blackout device. You only >> have to make the receiver question each satellite's signal often enough >> for it to rule it out. No way is CW necessary, or even desirable. >> >> As John suggested, someone (say the Chinese) could put these things in >> battery operated stuffed animals, and set them up to jam a little bit >> now and then. After Xmas, the GPS landscape would be littered with >> these >> little stealth jammers, and willing supplicants to replace their >> batteries. >> >> -Chuck >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > > E-mail message checked by Spyware Doctor (6.0.0.386) > Database version: 5.13700 > http://www.pctools.com/en/spyware-doctor-antivirus/ > > > > > > E-mail message checked by Spyware Doctor (6.0.0.386) > Database version: 5.13700 > http://www.pctools.com/en/spyware-doctor-antivirus/ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Mon Nov 16 00:56:23 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 01:56:23 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <20091116001319.0BAC3BCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091116001319.0BAC3BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <4B00A337.3070200@rubidium.dyndns.org> Hal Murray wrote: > cfharris at erols.com said: >> What makes you think it needs to be CW, and cannot be pulsed and >> chirped? > >> All it has to do is confuse the receiver enough so that you can't >> trust its readings. > > Why is pulse or chirp likely to be more confusing per W of jamming power? > > > I thought the GPS signal was spread spectrum so I wouldn't expect any simple > pulse or chirp to be better at jamming than noise over the appropriate > bandwidth. > > If you know the spread spectrum details (which must be public or the receiver > can't listen to the signal), then you might be able to mimic a satellite > signal. I think that needs the time, so you probably need to listen to the > signal you are jamming. > > Am I on the right track? Is there a trick I'm missing? (If so, how > complicated is it?) I think you are running into the jamming/spoofing definition of the problem. When you are jamming, you are transmitting a signal which just overshadows the propper signal but when you are spoofing you try to send a signal which looks like the propper signal. A spoofing attack is a different story altogether. For a spoofer to confuse a receiver, it either needs to be there when the receiver turns on or the spoofer needs to transmitt signals having a position so near the receivers current signals that it can't discriminate them and then track onto the wrong signals. The counter-measure towards spoofers is to used a keyed signal, in which case only delayed signal is available to the attacker, but for most cases the receiver should be able to handle that. For jamming I think chirps or phase-noise transmitters is effective since they select no particular feature of the spreading code, but induces error into both the weak and strong features, which is then shifted by the expected doppler frequency. The sensitivity of jamming energy for various offsets from the carrier for a pseudo-random sequence can be retrieved by Fourier-transform (DFT). Cheers, Magnus From magnus at rubidium.dyndns.org Mon Nov 16 01:01:25 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 02:01:25 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2294.12.6.201.222.1258331280.squirrel@popacctsnew.quik.com> References: <4B003189.4050000@erols.com> <4B008F3B.8030300@erols.com> <4B0092C9.1030400@rubidium.dyndns.org> <4B0098A2.4030303@erols.com> <2294.12.6.201.222.1258331280.squirrel@popacctsnew.quik.com> Message-ID: <4B00A465.6030408@rubidium.dyndns.org> J. Forster wrote: > Or even into MP3 players, iPods, laptops, or cell phones. Then they'd > wander all over the place too. With the latter two hosts, they could even > be controlled remotely and even be fairly powerful. Would you notice > having to recharge your battery a bit more often? There is one report in which the laptops of ambulances had CPU frequencies in the neighborhood (1,5 GHz or 1,6 GHz if I recall correctly) of the GPS band and the GPS receiver lost tracking so they essentially lost functionality. Cheers, Magnus From magnus at rubidium.dyndns.org Mon Nov 16 01:02:57 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 02:02:57 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: Message-ID: <4B00A4C1.5030909@rubidium.dyndns.org> Francesco Ledda wrote: > Considering that the GPS antenna in aircrafts is mounted on top of fuselage, > and that its radiation pattern is upward, it seems that a ground jammer will > have an uphill battle. Not all GPS receivers is sitting on flying airplanes. Far from it. Cheers, Magnus From cfharris at erols.com Mon Nov 16 01:04:43 2009 From: cfharris at erols.com (Chuck Harris) Date: Sun, 15 Nov 2009 20:04:43 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4B008F3B.8030300@erols.com> Message-ID: <4B00A52B.7000006@erols.com> Mike, A defective TV antenna preamp (oscillating in an uncontrolled manner), on board a boat in California wiped out GPS for several kilometers! Because it only wiped it out when the owner was watching TV, the interferrence went on for months. This is well documented. Do a google search and you will find the report from the guys that found the jammer. When a modern high sensitivity GPS receiver cannot get a fix through the shingled roof of a house, you have to understand that the signals are really weak. The folks selling commercial GPS jammers are being rather brutish with their methods. They are using sledge hammers where a little tack hammer would do nicely. -Chuck Mike Monett wrote: > Chuck Harris wrote: >> What makes you think it needs to be CW, and cannot be pulsed and >> chirped? >> >> All it has to do is confuse the receiver enough so that you can't >> trust its readings. >> >> -Chuck > > I said nothing about the type of modulation. The equipment I listed is > designed specifically to disrupt GPS. Presumably they use whatever > modulation method that gives the best results. > > However, GPS is spread-spectrum, so it inherently rejects noise that is > not correlated with the satellite signal. This means effective jamming > requires a lot more power than is available from a 9V transistor radio > battery, and even then, the range is only a few meters. From didier at cox.net Mon Nov 16 01:18:30 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 19:18:30 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2316.12.6.201.222.1258332689.squirrel@popacctsnew.quik.com> References: <2316.12.6.201.222.1258332689.squirrel@popacctsnew.quik.com> Message-ID: <4AE1510E4AFF412593C7936F1C1AAC00@d400> GPS receivers have considerable coding gain, which makes it possible for them to detect such low signals in the first place. The jamming signal will not benefit from the coding gain because it does not have the right coding and will be uncorrelated to the actual spread-spectrum signals the receiver is tracking. This is probably 30 dB or more. Also, you assume that your jammer has a similar antenna gain and radiation efficiency as the GPS transmitter on the satellite, that is unlikely. Bottom line, it is unlikely that a jammer running off a 9V battery, even on a baloon will jam the entire US for weeks. Can we go back to timing now? My 9V battery is running out... Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster > Sent: Sunday, November 15, 2009 6:51 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > Reference oscillator accuracy) > > See my earlier post. Briefly: > > Antennas do not have an infinite front-to-back ratio. (<40 dB) > > The path loss from a surface jammer to a plane (10 miles) is > many, many dB less than from plane to bird (15,000 miles). > > -John > > ============ > From die at dieconsulting.com Mon Nov 16 01:21:40 2009 From: die at dieconsulting.com (David I. Emery) Date: Sun, 15 Nov 2009 20:21:40 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4B008F3B.8030300@erols.com> Message-ID: <20091116012140.GB5736@pig.dieconsulting.com> On Sun, Nov 15, 2009 at 07:41:35PM -0500, Mike Monett wrote: One can clearly divide the targets into soft ones (GPS timing, AVR systems, some civilian aircraft nav, civilian vehicle nav etc) and some very hard ones (multiple frequency steered beam antenna military P/Y keyed systems which can take advantage of all the known tricks). Presumably there is now quite a bit of experience in the military with jamming their jam resistant systems (or trying to and failing) and presumably they have some well thought out strategies for neutralizing it or its impact... for them. However, there are many SOFT users who actually depend on GPS more than they realize who have gear that can be knocked out by weak jamming (as illustrated by interference cases from innocent sources like malfunctioning antenna preamps) very easily. Not clear to me what the effects of doing so over a wide area might be now or especially in 5-10 years from now when more and more stuff depends on GPS timing or location or frequency or all three. Civilian gear does not in general worry about jamming... and its operators rarely have the training or access to the reason it may not be functioning to know that jamming is happening. This is especially true of spoof jamming that attempts to create false timing or position as opposed to jamming that just causes an effective no GPS condition. John is right, that jamming that knocks out service or causes to be wrong intermittently would be just as effective in many cases as steady blanket jamming... especially if there is little expectation that this might be a threat. (Clearly the military has considered all this carefully, but not necessarily for the civilian uses they may not even know about). And while restoring a destroyed Loran C site might take a while, launching a new GPS satellite to replace one destroyed by some natural event (solar outbursts) or some man made event (clouds of debris - either deliberate or accidental) takes MUCH longer and cannot be hurried up much. I doubt many flight ready spares are kept around (including rocket and all the rest) and even if there are one or two a major event could take out more than that number if it is at all global in impact. -- Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." From jfor at quik.com Mon Nov 16 01:21:26 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 17:21:26 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4AE1510E4AFF412593C7936F1C1AAC00@d400> References: <2316.12.6.201.222.1258332689.squirrel@popacctsnew.quik.com> <4AE1510E4AFF412593C7936F1C1AAC00@d400> Message-ID: <2379.12.6.201.222.1258334486.squirrel@popacctsnew.quik.com> > GPS receivers have considerable coding gain, which makes it possible for > them to detect such low signals in the first place. The jamming signal > will > not benefit from the coding gain because it does not have the right coding > and will be uncorrelated to the actual spread-spectrum signals the > receiver > is tracking. > > This is probably 30 dB or more. > > Also, you assume that your jammer has a similar antenna gain and radiation > efficiency as the GPS transmitter on the satellite, that is unlikely. I don't assume ANY gain in the jammer. 0 dB. > Bottom line, it is unlikely that a jammer running off a 9V battery, even > on a balloon will jam the entire US for weeks. I never implied that. Nothing close. But a few hundred to tens of thousands, operating intermittantly, is another story. -John ========= From frledda at verizon.net Mon Nov 16 01:25:39 2009 From: frledda at verizon.net (Francesco Ledda) Date: Sun, 15 Nov 2009 19:25:39 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B00A4C1.5030909@rubidium.dyndns.org> References: <4B00A4C1.5030909@rubidium.dyndns.org> Message-ID: <000101ca665b$b4c09ee0$1e41dca0$@net> The one the counts ARE! ;) -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Magnus Danielson Sent: Sunday, November 15, 2009 7:03 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Francesco Ledda wrote: > Considering that the GPS antenna in aircrafts is mounted on top of fuselage, > and that its radiation pattern is upward, it seems that a ground jammer will > have an uphill battle. Not all GPS receivers is sitting on flying airplanes. Far from it. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ From cfharris at erols.com Mon Nov 16 01:31:34 2009 From: cfharris at erols.com (Chuck Harris) Date: Sun, 15 Nov 2009 20:31:34 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B009F4E.5020600@rubidium.dyndns.org> References: <4B003189.4050000@erols.com> <4B008F3B.8030300@erols.com> <4B0092C9.1030400@rubidium.dyndns.org> <4B0098A2.4030303@erols.com> <4B009F4E.5020600@rubidium.dyndns.org> Message-ID: <4B00AB76.1030109@erols.com> Magnus Danielson wrote: > Well, then you have to consider what the potential gain would be from > such an attack. I fail to see the upside of that particular scenario. It > would draw the attention over to them and in a field I think they rather > stay calm about. Their ability to pull it off as such should not be > doubted, but their resoning for it. Rather inefficient actually. The Chinese seem to have a difficulty worrying about the ethics of some of the things they do towards others. Some simple examples would be the lead in paints and plastics used in toys, melamine powder in milk, and pet food, pork flavored cardboard in frozen dumplings, tainted raw ingredients for heprin, the list goes on and on. It may not be in the nation's political interests to jam our GPS signals through toys, or other devices, but ... from what I have seen thus far, you could easily find several dozen manufacturers in China that would be willing to turn a blind eye to such a trojan payload in return for a few bucks. -Chuck Harris From jfor at quik.com Mon Nov 16 01:29:54 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 17:29:54 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <000101ca665b$b4c09ee0$1e41dca0$@net> References: <4B00A4C1.5030909@rubidium.dyndns.org> <000101ca665b$b4c09ee0$1e41dca0$@net> Message-ID: <2392.12.6.201.222.1258334994.squirrel@popacctsnew.quik.com> Maybe, but what happens if the GPS in a large metropolitan area that is overflown by a mix including General Aviation goes wonky? LA comes to mind because there is a lot of north-south traffic directly over LAX. -John =============== > The one the counts ARE! ;) > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Magnus Danielson > Sent: Sunday, November 15, 2009 7:03 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator > accuracy) > > Francesco Ledda wrote: >> Considering that the GPS antenna in aircrafts is mounted on top of > fuselage, >> and that its radiation pattern is upward, it seems that a ground jammer > will >> have an uphill battle. > > Not all GPS receivers is sitting on flying airplanes. Far from it. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > > E-mail message checked by Spyware Doctor (6.0.0.386) > Database version: 5.13700 > http://www.pctools.com/en/spyware-doctor-antivirus/ > > > > > > E-mail message checked by Spyware Doctor (6.0.0.386) > Database version: 5.13700 > http://www.pctools.com/en/spyware-doctor-antivirus/ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From didier at cox.net Mon Nov 16 01:33:16 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 19:33:16 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B00A4C1.5030909@rubidium.dyndns.org> References: <4B00A4C1.5030909@rubidium.dyndns.org> Message-ID: <72B8FB46D87A4CF2A12632F40082FEFE@d400> Not all GPSs are on airplanes, but those I am really worried about are. I don't care if the GPS receiver in my cell phone stops working in some locations, it does not work everywhere to begin with (like in the house, I can't use it to find the bathroom in the dark...), but I worry that the one guiding a missile or a fighter plane might not work. I also worry that the one abord a large passenger aircraft might not work. Most of those that are stationary or move on the ground or on water, I am not too worried about. For instance, the local garbage pickup people use GPS to locate the houses of customers who have unusual (large or unsafe, or possibly contaminating) garbage to pickup. I have had a dead TV on the side of my house for 3 weeks, three times I called and 3 times they missed it because the GPS guided them to my front door (my normal mailing address), but I live on a corner lot and the garbage pickup is on the side of the house, by the garage. If that particular GPS receiver stopped working and forced the employees to look around, it would not bother me (the TV ended up in the trash can. After 3 times and 3 weeks, I assumed I had done a reasonable attempt at avoiding putting too much lead in the garbage, and it had to go.) Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Magnus Danielson > Sent: Sunday, November 15, 2009 7:03 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > Reference oscillator accuracy) > > Francesco Ledda wrote: > > Considering that the GPS antenna in aircrafts is mounted on top of > > fuselage, and that its radiation pattern is upward, it seems that a > > ground jammer will have an uphill battle. > > Not all GPS receivers is sitting on flying airplanes. Far from it. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From brahn at woh.rr.com Mon Nov 16 01:45:13 2009 From: brahn at woh.rr.com (Bruce Rahn) Date: Sun, 15 Nov 2009 20:45:13 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <20091116001319.0BAC3BCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091116001319.0BAC3BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <4B00AEA9.5000208@woh.rr.com> Hal Murray wrote: > cfharris at erols.com said: > >> What makes you think it needs to be CW, and cannot be pulsed and >> chirped? >> > > >> All it has to do is confuse the receiver enough so that you can't >> trust its readings. >> > > Why is pulse or chirp likely to be more confusing per W of jamming power? Perhaps this reference will answer some of the questions present here: http://www.navcomtech.com/Support/Download/Sapphire%20Jamming%20Test%20Report%208%20Jan%202007v3.pdf One factor I have not seen anyone address is the effectiveness of jamming as a function of the receiver state. A GPS receiver will be much more susceptible to jamming when it is trying to acquire and lock onto a satellite signal than it is after lock and tracking has been achieved. Bruce, WB9ANQ -- Bruce Rahn Wisdom has two parts: 1. having a lot to say; and 2. not saying it! From justin at fuzzythinking.com Mon Nov 16 01:47:31 2009 From: justin at fuzzythinking.com (Justin Pinnix) Date: Sun, 15 Nov 2009 20:47:31 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <72B8FB46D87A4CF2A12632F40082FEFE@d400> References: <4B00A4C1.5030909@rubidium.dyndns.org> <72B8FB46D87A4CF2A12632F40082FEFE@d400> Message-ID: Contrary to popular belief, us pilots do know how to fly without GPS. I have never seen an IFR aircraft with a GPS that didn't also have a VOR receiver. Any VFR aircraft can be navigated using the Mk I eyeball. IFR certified GPSes have integrity monitoring. So, if the signal gets jammed or there is another system failure, the approach should be aborted and the flight switched to another navigation means. This LORAN debate is all well and good, but most of the general aviation fleet does not have LORAN receivers. They haven't been manufactured in years. On Sun, Nov 15, 2009 at 8:33 PM, Didier Juges wrote: > Not all GPSs are on airplanes, but those I am really worried about are. > > I don't care if the GPS receiver in my cell phone stops working in some > locations, it does not work everywhere to begin with (like in the house, I > can't use it to find the bathroom in the dark...), but I worry that the one > guiding a missile or a fighter plane might not work. I also worry that the > one abord a large passenger aircraft might not work. Most of those that are > stationary or move on the ground or on water, I am not too worried about. > > For instance, the local garbage pickup people use GPS to locate the houses > of customers who have unusual (large or unsafe, or possibly contaminating) > garbage to pickup. I have had a dead TV on the side of my house for 3 > weeks, > three times I called and 3 times they missed it because the GPS guided them > to my front door (my normal mailing address), but I live on a corner lot > and > the garbage pickup is on the side of the house, by the garage. If that > particular GPS receiver stopped working and forced the employees to look > around, it would not bother me (the TV ended up in the trash can. After 3 > times and 3 weeks, I assumed I had done a reasonable attempt at avoiding > putting too much lead in the garbage, and it had to go.) > > Didier > > > -----Original Message----- > > From: time-nuts-bounces at febo.com > > [mailto:time-nuts-bounces at febo.com] On Behalf Of Magnus Danielson > > Sent: Sunday, November 15, 2009 7:03 PM > > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > > Reference oscillator accuracy) > > > > Francesco Ledda wrote: > > > Considering that the GPS antenna in aircrafts is mounted on top of > > > fuselage, and that its radiation pattern is upward, it seems that a > > > ground jammer will have an uphill battle. > > > > Not all GPS receivers is sitting on flying airplanes. Far from it. > > > > Cheers, > > Magnus > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From magnus at rubidium.dyndns.org Mon Nov 16 01:49:10 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 02:49:10 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4B008F3B.8030300@erols.com> Message-ID: <4B00AF96.8000105@rubidium.dyndns.org> Mike, Mike Monett wrote: > I said nothing about the type of modulation. The equipment I listed is > designed specifically to disrupt GPS. Presumably they use whatever > modulation method that gives the best results. > > However, GPS is spread-spectrum, so it inherently rejects noise that is > not correlated with the satellite signal. This means effective jamming > requires a lot more power than is available from a 9V transistor radio > battery, and even then, the range is only a few meters. The power of de-correlation is related to the length of the pseudo-random sequence. This relates back to the codes auto-correlation shape. The C/A code has a length of 1023 chips, giving a correlation gain of about 30 dB. The P code has a length of 7*86400*10,23E6 chips (a GPS week) but only fraction of that can be used for de-correlation. Looking at the detailed codes, the vunerability of C/A codes is worse, for PRN 1 the suppression is only -22,71 dB at 42 kHz sideband. But these coding gains comes to no use if the input is saturated for most of the times. Simple AGC strategies would allow the AGC to be captured by the CW signal for instance. Lack of filtering would allow out-of-bandwidth signals to infect the input etc. etc. Pre-digitalization code de-correlation is less sensitive to jamming, but comes at the price of 3 times number of channels analog decorrelators and integrators. Then again, it only solves part of the problem. The tracking threshold of the particular receiver in its environment has a huge effect. Support systems such as clock, movement sensors etc. can allow for tighter loop filters and thus allow the channels having a lower threshold and that would aid in the jamming resistance too. Regardless, the code-lengths isn't a particular good measure on the resistance to jamming. The P(Y) code is only about 10 dB better than C/A code in that respect, and M code gives another dB or so. Cheers, Magnus From didier at cox.net Mon Nov 16 02:11:13 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 20:11:13 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com> References: <4B003189.4050000@erols.com> <4B009C02.3000309@xtra.co.nz> <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com> Message-ID: The commercial jammers referred to in an earlier post advertise 10 to 45m or so range, with significant power levels and battery life measured in a few hours. Considering that these devices are illegal to begin with, I have to assume that these figures are probably optimistic (optimistic advertisement is probably the least of their concern.) If I were a pilot, I would probably be more worried about the kid playing with his Nintendo in 15A (or his father trying to retrieve his email with his GSM smart phone) during approach than a jammer on the ground. Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster > Sent: Sunday, November 15, 2009 6:38 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > Reference oscillator accuracy) > > Even 10 KM is pretty useful. If the thing were solar powered > with a supercap "battery" it could easly transmit for say 2 > minutes per hour w/ significant power. It'd be hard to find > if the on times were generated by a multiple fedback CMOS > shift register. > > -John > From bruce.griffiths at xtra.co.nz Mon Nov 16 02:21:11 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 16 Nov 2009 15:21:11 +1300 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <4B003189.4050000@erols.com> <4B009C02.3000309@xtra.co.nz> <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com> Message-ID: <4B00B717.7020507@xtra.co.nz> Didier As jammers those devices are extremely inefficient. They may well rely on the inefficient generation and radiation of a very high order harmonic of the clock of an unshielded legal device. A commercial GPS receiver may require a signal as small as 60dB (depends on the operating mode, and receiver design) above the GPS signal at the receiver input. An ERP of a few microwatts should suffice to achieve the claimed range. Bruce Didier Juges wrote: > The commercial jammers referred to in an earlier post advertise 10 to 45m or > so range, with significant power levels and battery life measured in a few > hours. Considering that these devices are illegal to begin with, I have to > assume that these figures are probably optimistic (optimistic advertisement > is probably the least of their concern.) > > If I were a pilot, I would probably be more worried about the kid playing > with his Nintendo in 15A (or his father trying to retrieve his email with > his GSM smart phone) during approach than a jammer on the ground. > > Didier > > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster >> Sent: Sunday, November 15, 2009 6:38 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] The Demise of LORAN (was Re: >> Reference oscillator accuracy) >> >> Even 10 KM is pretty useful. If the thing were solar powered >> with a supercap "battery" it could easly transmit for say 2 >> minutes per hour w/ significant power. It'd be hard to find >> if the on times were generated by a multiple fedback CMOS >> shift register. >> >> -John >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From didier at cox.net Mon Nov 16 02:22:50 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 20:22:50 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <20091116003007.1F5B0BCFC@ip-64-139-1-69.sjc.megapath.net> References: Message from "Mike Monett" of "Sun, 15 Nov 2009 18:18:38 EST." <20091116003007.1F5B0BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <6B130F3EB4FB484DA12F424B6236CA82@d400> I think the problem with the Monterey Bay jammer was that he was jamming the DGPS correction signal, not the GPS signal itself. The DGPS correction signal is sent over the UHF band. Most marine GPS are DGPS because they need the better resolution it provides, particularly to find buoys and channel markers in the fog. The DGPS correction signal does not benefit from the spread-spectrum modulation and associated jamming resistance of the GPS signal itself. Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray > Sent: Sunday, November 15, 2009 6:30 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > Reference oscillator accuracy) > > > Jamming Range : Average 40 meters radius Output Power : > Total 6.5 > > Watt > > > ratio : 40/6.5 = 6.15 meters/watt > > Isn't received power 1/R-squared? > > I think those calculations should be radius-squared/watts > > > I find it interesting that the products designed as jammers > have ranges of "only" a few 10s of meters while a recent > message here said 1/2 mile from a digital-radio link that was > transmitting on 315 MHz. (aka designed for something else > rather than as a jammer) > > Similarly, the Monterey Bay jammer wasn't trying to be a > jammer, and it wiped out a huge area. > From die at dieconsulting.com Mon Nov 16 02:30:05 2009 From: die at dieconsulting.com (David I. Emery) Date: Sun, 15 Nov 2009 21:30:05 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <6B130F3EB4FB484DA12F424B6236CA82@d400> References: <20091116003007.1F5B0BCFC@ip-64-139-1-69.sjc.megapath.net> <6B130F3EB4FB484DA12F424B6236CA82@d400> Message-ID: <20091116023005.GB8101@pig.dieconsulting.com> On Sun, Nov 15, 2009 at 08:22:50PM -0600, Didier Juges wrote: > I think the problem with the Monterey Bay jammer was that he was jamming the > DGPS correction signal, not the GPS signal itself. The DGPS correction > signal is sent over the UHF band. Most marine GPS are DGPS because they need > the better resolution it provides, particularly to find buoys and channel > markers in the fog. The DGPS correction signal does not benefit from the > spread-spectrum modulation and associated jamming resistance of the GPS > signal itself. That is the first I've heard of a UHF DGPS correction transmission can you provide a frequency and modulation mode ? Most I know of are re purposed LF NDBs or similar transmitters in the 200 to 400 KHz or so range that transmit a PSK'd carrier with the DGPS data at fairly low speed on it. I have heard of cases of wide area GPS outages noted by many folks with NON DGPS receivers (DGPS receivers mostly will just indicate no DGPS available and still show a pretty good position) that were caused by UHF signals on the L2 frequency... though I am sure there are incidents of accidental interference to LF or other distribution of DGPS. -- Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." From didier at cox.net Mon Nov 16 02:55:32 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 20:55:32 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <20091116023005.GB8101@pig.dieconsulting.com> References: <20091116003007.1F5B0BCFC@ip-64-139-1-69.sjc.megapath.net><6B130F3EB4FB484DA12F424B6236CA82@d400> <20091116023005.GB8101@pig.dieconsulting.com> Message-ID: <136CA0E982244F2DBE7A6A4EA9E2B745@d400> I was shooting from the hip, I thought the DGPS signals were sent at UHF, but maybe not, but that's not the point. The point is that you can significantly affect DGPS operation without having to jam the GPS signal itself. I found a reference saying the Monterey Bay jammer was jamming the DGPS station, rather than the DGPS signal. I have not found the original article I was looking for about it, but I think I remember that the boaters and Coast Guards were the most affected, as you should expect because they rely on and need the additional accuracy of the DGPS system. Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of David I. Emery > Sent: Sunday, November 15, 2009 8:30 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > Reference oscillatoraccuracy) > > > That is the first I've heard of a UHF DGPS correction > transmission > can you provide a frequency and modulation mode ? Most I > know of are > re purposed LF NDBs or similar transmitters in the 200 to 400 > KHz or so range that transmit a PSK'd carrier with the DGPS > data at fairly low speed on it. > > I have heard of cases of wide area GPS outages noted by > many folks with NON DGPS receivers (DGPS receivers mostly > will just indicate no DGPS available and still show a pretty > good position) that were caused by UHF signals on the L2 > frequency... though I am sure there are incidents of > accidental interference to LF or other distribution of DGPS. > From didier at cox.net Mon Nov 16 02:56:36 2009 From: didier at cox.net (Didier Juges) Date: Sun, 15 Nov 2009 20:56:36 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B00B717.7020507@xtra.co.nz> References: <4B003189.4050000@erols.com> <4B009C02.3000309@xtra.co.nz> <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com> <4B00B717.7020507@xtra.co.nz> Message-ID: <0767F9980C9944C79457D84BEC499933@d400> Bruce, I agree with your calculation and conclusion, as far as commercial consumer GPS receivers are concerned. A data sheet that was linked in a previous post for an aviation-grade commercial GPS receiver indicated resistance to signals -30dBm at the receiver input. That is quite considerable, and much better than the hand-held consumer units (by 30dB?) I would expect planes and other potential "high value targets" to have receivers of similar performance. I don't disagree that it would be fairly easy to disrupt the consumer devices, but other than a few missed appointments and frustrated gadget freaks, and the occasional emergency vehicle not finding its way to the scene of an accident, that would be more of a problem) I am not too worried about the consequences of that. The thread started with the loss of the LORAN system, and nobody (maybe I am going out on a limb here) ever used a LORAN receiver in his car to find the nearest restaurant :) I think the people who should complain the most about the loss of LORAN are the boaters, but they are the one who embrassed GPS the first and are it's biggest advocates!!! I know, I live on the coast of Florida. Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Bruce Griffiths > Sent: Sunday, November 15, 2009 8:21 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > Reference oscillator accuracy) > > Didier > > As jammers those devices are extremely inefficient. > They may well rely on the inefficient generation and > radiation of a very high order harmonic of the clock of an > unshielded legal device. > > A commercial GPS receiver may require a signal as small as > 60dB (depends on the operating mode, and receiver design) > above the GPS signal at the receiver input. > An ERP of a few microwatts should suffice to achieve the > claimed range. > > Bruce > > Didier Juges wrote: > > The commercial jammers referred to in an earlier post > advertise 10 to > > 45m or so range, with significant power levels and battery life > > measured in a few hours. Considering that these devices are > illegal to > > begin with, I have to assume that these figures are probably > > optimistic (optimistic advertisement is probably the least of their > > concern.) > > > > If I were a pilot, I would probably be more worried about the kid > > playing with his Nintendo in 15A (or his father trying to > retrieve his > > email with his GSM smart phone) during approach than a > jammer on the ground. > > > > Didier > > > > > >> -----Original Message----- > >> From: time-nuts-bounces at febo.com > >> [mailto:time-nuts-bounces at febo.com] On Behalf Of J. Forster > >> Sent: Sunday, November 15, 2009 6:38 PM > >> To: Discussion of precise time and frequency measurement > >> Subject: Re: [time-nuts] The Demise of LORAN (was Re: > >> Reference oscillator accuracy) > >> > >> Even 10 KM is pretty useful. If the thing were solar > powered with a > >> supercap "battery" it could easly transmit for say 2 > minutes per hour > >> w/ significant power. It'd be hard to find if the on times were > >> generated by a multiple fedback CMOS shift register. > >> > >> -John > >> > >> > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jmfranke at cox.net Mon Nov 16 03:19:44 2009 From: jmfranke at cox.net (jmfranke) Date: Sun, 15 Nov 2009 22:19:44 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Referenceoscillatoraccuracy) References: <20091116003007.1F5B0BCFC@ip-64-139-1-69.sjc.megapath.net><6B130F3EB4FB484DA12F424B6236CA82@d400><20091116023005.GB8101@pig.dieconsulting.com> <136CA0E982244F2DBE7A6A4EA9E2B745@d400> Message-ID: <8D1D4AD041E14302B4A01F04B653DC60@Franke> For the marina story, see: http://www.gpsworld.com/gps/system-challenge/the-hunt-rfi-776 The L1 signal was unintentionally jammed. John WA4WDL -------------------------------------------------- From: "Didier Juges" Sent: Sunday, November 15, 2009 9:55 PM To: "'Discussion of precise time and frequency measurement'" Subject: Re: [time-nuts] The Demise of LORAN (was Re: Referenceoscillatoraccuracy) > I was shooting from the hip, I thought the DGPS signals were sent at UHF, > but maybe not, but that's not the point. The point is that you can > significantly affect DGPS operation without having to jam the GPS signal > itself. > > I found a reference saying the Monterey Bay jammer was jamming the DGPS > station, rather than the DGPS signal. I have not found the original > article > I was looking for about it, but I think I remember that the boaters and > Coast Guards were the most affected, as you should expect because they > rely > on and need the additional accuracy of the DGPS system. > > Didier > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of David I. Emery >> Sent: Sunday, November 15, 2009 8:30 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] The Demise of LORAN (was Re: >> Reference oscillatoraccuracy) >> >> >> That is the first I've heard of a UHF DGPS correction >> transmission >> can you provide a frequency and modulation mode ? Most I >> know of are >> re purposed LF NDBs or similar transmitters in the 200 to 400 >> KHz or so range that transmit a PSK'd carrier with the DGPS >> data at fairly low speed on it. >> >> I have heard of cases of wide area GPS outages noted by >> many folks with NON DGPS receivers (DGPS receivers mostly >> will just indicate no DGPS available and still show a pretty >> good position) that were caused by UHF signals on the L2 >> frequency... though I am sure there are incidents of >> accidental interference to LF or other distribution of DGPS. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From jfor at quik.com Mon Nov 16 03:17:37 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 19:17:37 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <0767F9980C9944C79457D84BEC499933@d400> References: <4B003189.4050000@erols.com> <4B009C02.3000309@xtra.co.nz> <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com> <4B00B717.7020507@xtra.co.nz> <0767F9980C9944C79457D84BEC499933@d400> Message-ID: <2486.12.6.201.222.1258341457.squirrel@popacctsnew.quik.com> My first contact with LORAN was at the bankrupcy of a local company that supplied tracking and location services for trucking companies. The trucks had a receiver that sent data back to home base via two-way radio and home pbase computed positions. I was only nteresteed in buying their mimis. In the early 80s I was playing around with uP (8085) based LORAN receivers (Made by Appelco/Raytheon). One version read out time differences and a more advanced (w/ 2x 8085s) version read out Lat & Long directly. Either would pinpoint my location to 100' class. It was accurate navigation in a two-way radio sized box. There were, of course, no map or chart displays. Imagine what 20+ years of development would have brought. -John ============= > Bruce, > > I agree with your calculation and conclusion, as far as commercial > consumer > GPS receivers are concerned. > > A data sheet that was linked in a previous post for an aviation-grade > commercial GPS receiver indicated resistance to signals -30dBm at the > receiver input. That is quite considerable, and much better than the > hand-held consumer units (by 30dB?) > > I would expect planes and other potential "high value targets" to have > receivers of similar performance. > > I don't disagree that it would be fairly easy to disrupt the consumer > devices, but other than a few missed appointments and frustrated gadget > freaks, and the occasional emergency vehicle not finding its way to the > scene of an accident, that would be more of a problem) I am not too > worried > about the consequences of that. > > The thread started with the loss of the LORAN system, and nobody (maybe I > am > going out on a limb here) ever used a LORAN receiver in his car to find > the > nearest restaurant :) > > I think the people who should complain the most about the loss of LORAN > are > the boaters, but they are the one who embrassed GPS the first and are it's > biggest advocates!!! I know, I live on the coast of Florida. > > Didier From bill at iaxs.net Mon Nov 16 03:29:30 2009 From: bill at iaxs.net (Bill Hawkins) Date: Sun, 15 Nov 2009 21:29:30 -0600 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy) In-Reply-To: <0767F9980C9944C79457D84BEC499933@d400> References: <4B003189.4050000@erols.com> <4B009C02.3000309@xtra.co.nz> <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com><4B00B717.7020507@xtra.co.nz> <0767F9980C9944C79457D84BEC499933@d400> Message-ID: Ahh, must jump into feeding frenzy . . . Here we find the limitations of the 3 pound (1.5 kilogram) human brain. One must become a specialist to become informed on a particular field, because the scope of that field increases exponentially with time (the subject of this group). Not everyone keeps up, and not everyone who looks at the bleeding edge thinks that past experience and knowledge has been included. And so we enter an alternative universe similar to the discussion of politics or religion. Think about why all of these diverse opinions exist. The brain can't comprehend something for which it has no comprehending structures of nerves. We stopped having enough structures sometime in the 16th century. We forge into the future only because we specialize into areas that do fit the brain, but no two people have the same brain structures. And so, dear friends, we are descending not into Alice's rabbit hole, but a rat hole with an infinite number of twisty little passages, all somewhat alike. The decision was made, some time ago. The time for discussion has passed. Please return the list to its subject matter. YMMV Bill Hawkins From die at dieconsulting.com Mon Nov 16 03:33:07 2009 From: die at dieconsulting.com (David I. Emery) Date: Sun, 15 Nov 2009 22:33:07 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <0767F9980C9944C79457D84BEC499933@d400> References: <4B003189.4050000@erols.com> <4B00B717.7020507@xtra.co.nz> <0767F9980C9944C79457D84BEC499933@d400> Message-ID: <20091116033307.GA8612@pig.dieconsulting.com> On Sun, Nov 15, 2009 at 08:56:36PM -0600, Didier Juges wrote: > > I don't disagree that it would be fairly easy to disrupt the consumer > devices, but other than a few missed appointments and frustrated gadget > freaks, and the occasional emergency vehicle not finding its way to the > scene of an accident, that would be more of a problem) I am not too worried > about the consequences of that. GPS has been widely used for time and frequency sync in radio systems of various sorts - some depend on it for successful simulcast from multiple transmitters (including many public safety radio systems) and while there is SUPPOSED to be significant holdover, there is are always those situations where nobody has EVER checked that it works... And what will holdover do about LONG TERM outages of GPS ? Perhaps folks are willing to bet the whole infrastructure on the supposition that we could NEVER see a complete long term loss of signal (using civilian receivers with modest anti jam abilities) in a particular location or region - I am not exactly sure what alternative might exist though I guess there are some for time and frequency - terrestrial GPS beacons from high points that could lock up a cell system in a region come to mind... And more and more and more stuff depends on more or less ignorant and sometimes not very bright operators expecting that the GPS positions are always there or they don't know what to do. And if GPS is almost always reliably there there may well be little or no practical training about what to do if it fails. Failure modes and paths in code and procedures (and sometimes even actual hardware) which aren't often tested or exercised usually fail when actually needed and often in entirely unanticipated ways - maybe the backup ALSO depends on GPS in some way the system designers never thought about (or knew could happen)... LORAN C represents a viable (albeit not often deployed) backup to time and frequency control and could be implemented in modern hardware as a backup location service at reasonably low cost for those applications where that is important enough. > > The thread started with the loss of the LORAN system, and nobody (maybe I am > going out on a limb here) ever used a LORAN receiver in his car to find the > nearest restaurant :) Actually readers of this list have, though not in recent times I guess. > > I think the people who should complain the most about the loss of LORAN are > the boaters, but they are the one who embrassed GPS the first and are it's > biggest advocates!!! I know, I live on the coast of Florida. An enhanced LORAN that has some of the accuracy and automation of a GPS receiver exists... I suspect boaters care most about convenience (and accuracy) and found GPS easier. Certainly so compared to earlier LORAN C gear. And of course there is another issue with GPS, it is controlled by the DOD and is supposed to have the ability to deny service in a region if conditions are sufficiently apocalyptic to require it. For folks worried about this (more outside than inside the US obviously) LORAN is a local resource they may control and certainly can if they make a more or less modest investment in the ability to do so. Some (large) players are of course planning their own space based systems for just this reason but LORAN can be implemented by most nation states... -- Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." From die at dieconsulting.com Mon Nov 16 03:37:25 2009 From: die at dieconsulting.com (David I. Emery) Date: Sun, 15 Nov 2009 22:37:25 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <2486.12.6.201.222.1258341457.squirrel@popacctsnew.quik.com> References: <4B003189.4050000@erols.com> <4B00B717.7020507@xtra.co.nz> <0767F9980C9944C79457D84BEC499933@d400> <2486.12.6.201.222.1258341457.squirrel@popacctsnew.quik.com> Message-ID: <20091116033725.GA8989@pig.dieconsulting.com> On Sun, Nov 15, 2009 at 07:17:37PM -0800, J. Forster wrote: > There were, of course, no map or chart displays. Imagine what 20+ years of > development would have brought. E Loran could supply the same basic position information as input to charting and mapping software as GPS does... most of the code doesn't care where the position came from one wit.... But I am sure you know that (we are in violant agreement). > -John > -- Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." From jfor at quik.com Mon Nov 16 03:42:28 2009 From: jfor at quik.com (J. Forster) Date: Sun, 15 Nov 2009 19:42:28 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <20091116033307.GA8612@pig.dieconsulting.com> References: <4B003189.4050000@erols.com> <4B00B717.7020507@xtra.co.nz> <0767F9980C9944C79457D84BEC499933@d400> <20091116033307.GA8612@pig.dieconsulting.com> Message-ID: <2509.12.6.201.222.1258342948.squirrel@popacctsnew.quik.com> In fact, GPS has performed so well, it has become "part of the furniture" and it is really hard now to assess the full impact its loss would have. Another overlooked aspect would be the perceived impact of a number of failures. Just look at the hoohaws over lead in toys, defective cribs, tainted beef, tainted pet food, flamable kids sleepware, trace chemicals in bottles and many other things. LORAN is cheap insurance, IMO. A modern dual receiver could compare LORAN and GPS positions to provide very high confidence levels at low incremental cost. -John ================= > On Sun, Nov 15, 2009 at 08:56:36PM -0600, Didier Juges wrote: >> >> I don't disagree that it would be fairly easy to disrupt the consumer >> devices, but other than a few missed appointments and frustrated gadget >> freaks, and the occasional emergency vehicle not finding its way to the >> scene of an accident, that would be more of a problem) I am not too >> worried >> about the consequences of that. > > GPS has been widely used for time and frequency sync in radio > systems of various sorts - some depend on it for successful simulcast > from multiple transmitters (including many public safety radio systems) > and while there is SUPPOSED to be significant holdover, there is are > always those situations where nobody has EVER checked that it works... > And what will holdover do about LONG TERM outages of GPS ? Perhaps > folks are willing to bet the whole infrastructure on the supposition that > we could NEVER see a complete long term loss of signal (using civilian > receivers with modest anti jam abilities) in a particular location or > region - I am not exactly sure what alternative might exist though I > guess there are some for time and frequency - terrestrial GPS beacons > from high points that could lock up a cell system in a region come to > mind... > > And more and more and more stuff depends on more or less > ignorant and sometimes not very bright operators expecting that the GPS > positions are always there or they don't know what to do. And if GPS > is almost always reliably there there may well be little or no practical > training about what to do if it fails. Failure modes and paths in code > and procedures (and sometimes even actual hardware) which aren't often > tested or exercised usually fail when actually needed and often in > entirely unanticipated ways - maybe the backup ALSO depends on GPS in > some way the system designers never thought about (or knew could > happen)... > > LORAN C represents a viable (albeit not often deployed) backup > to time and frequency control and could be implemented in modern > hardware as a backup location service at reasonably low cost for those > applications where that is important enough. > >> >> The thread started with the loss of the LORAN system, and nobody (maybe >> I am >> going out on a limb here) ever used a LORAN receiver in his car to find >> the >> nearest restaurant :) > > Actually readers of this list have, though not in recent times I guess. >> >> I think the people who should complain the most about the loss of LORAN >> are >> the boaters, but they are the one who embrassed GPS the first and are >> it's >> biggest advocates!!! I know, I live on the coast of Florida. > > An enhanced LORAN that has some of the accuracy and automation > of a GPS receiver exists... I suspect boaters care most about > convenience (and accuracy) and found GPS easier. Certainly so compared > to earlier LORAN C gear. > > And of course there is another issue with GPS, it is controlled > by the DOD and is supposed to have the ability to deny service in a > region if conditions are sufficiently apocalyptic to require it. For > folks worried about this (more outside than inside the US obviously) > LORAN is a local resource they may control and certainly can if they > make a more or less modest investment in the ability to do so. Some > (large) players are of course planning their own space based systems for > just this reason but LORAN can be implemented by most nation states... > > -- > Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass > 02493 > "An empty zombie mind with a forlorn barely readable weatherbeaten > 'For Rent' sign still vainly flapping outside on the weed encrusted pole - > in > celebration of what could have been, but wasn't and is not to be now > either." From james.p.lux at jpl.nasa.gov Mon Nov 16 04:55:25 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Sun, 15 Nov 2009 20:55:25 -0800 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <4B009F4E.5020600@rubidium.dyndns.org> Message-ID: A *much* more effective and cheap strategy is a repeater jammer.. Receive the signal and retransmit it: two antennas and an amplifier. The victim sees the delayed retransmitted signal at a higher level than the direct one. It's sort of like creating fake multipath interference. No need for PN generators, oscillators, etc. Granted, a smart receiver that *understands* the relationship between SV to user geometry and doppler can beat it (because the carrier phase and PN phase of the repeated signal won't be consistent with the geometry), but the run of the mill PN tracking loop probably won't. Most inexpensive receivers use a single bit sampler, so a suitable CW tone could also probably jam it effectively, but might require some knowledge of the victim receiver to pick an appropriate frequency (i.e. You'd need to know the sampling rate.) On 11/15/09 4:39 PM, "Magnus Danielson" wrote: > Chuck Harris wrote: >> Magnus Danielson wrote: >>> Chuck, >>> >>> Chuck Harris wrote: >>>> What makes you think it needs to be CW, and cannot be pulsed and >>>> chirped? >>> >>> May I roll in a noise jammer into the debate? >> >> Absolutely! They can be extremely power efficient. Raise the noise >> floor in the vicinity of the receiver, and it is all done. >> >> Probably the easiest solution would be to take a PN source and use it >> to drive a pulser that pulses a chirp oscillator. If you are feeling >> really polite, you could put a bandpass filter on the thing to protect >> other services. > > The schematic out there is a PN source feeding an OCXO and then > amplified. Crystal loop to keep fairly centered. More or less the same > as personalized phone jammers do. Very simple design. > From bg at lysator.liu.se Mon Nov 16 06:15:16 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Mon, 16 Nov 2009 07:15:16 +0100 (CET) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <000101ca665b$b4c09ee0$1e41dca0$@net> References: <4B00A4C1.5030909@rubidium.dyndns.org> <000101ca665b$b4c09ee0$1e41dca0$@net> Message-ID: <52259.87.227.52.225.1258352116.squirrel@webmail.lysator.liu.se> The aircrafts that really count should work without GPS! > The one the counts ARE! ;) > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Magnus Danielson > Sent: Sunday, November 15, 2009 7:03 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator > accuracy) > > Francesco Ledda wrote: >> Considering that the GPS antenna in aircrafts is mounted on top of > fuselage, >> and that its radiation pattern is upward, it seems that a ground jammer > will >> have an uphill battle. > > Not all GPS receivers is sitting on flying airplanes. Far from it. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > > E-mail message checked by Spyware Doctor (6.0.0.386) > Database version: 5.13700 > http://www.pctools.com/en/spyware-doctor-antivirus/ > > > > > > E-mail message checked by Spyware Doctor (6.0.0.386) > Database version: 5.13700 > http://www.pctools.com/en/spyware-doctor-antivirus/ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From bg at lysator.liu.se Mon Nov 16 06:19:39 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Mon, 16 Nov 2009 07:19:39 +0100 (CET) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <6B130F3EB4FB484DA12F424B6236CA82@d400> References: Message from "Mike Monett" of "Sun, 15 Nov 2009 18:18:38 EST." <20091116003007.1F5B0BCFC@ip-64-139-1-69.sjc.megapath.net> <6B130F3EB4FB484DA12F424B6236CA82@d400> Message-ID: <52266.87.227.52.225.1258352379.squirrel@webmail.lysator.liu.se> With SA off, the difference between marine DGPS and stand alone GPS is not that significant. If my memory serves me right the Monterey jammer did jam at L1. -- Bj?rn > I think the problem with the Monterey Bay jammer was that he was jamming > the > DGPS correction signal, not the GPS signal itself. The DGPS correction > signal is sent over the UHF band. Most marine GPS are DGPS because they > need > the better resolution it provides, particularly to find buoys and channel > markers in the fog. The DGPS correction signal does not benefit from the > spread-spectrum modulation and associated jamming resistance of the GPS > signal itself. > > Didier > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray >> Sent: Sunday, November 15, 2009 6:30 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] The Demise of LORAN (was Re: >> Reference oscillator accuracy) >> >> > Jamming Range : Average 40 meters radius Output Power : >> Total 6.5 >> > Watt >> >> > ratio : 40/6.5 = 6.15 meters/watt >> >> Isn't received power 1/R-squared? >> >> I think those calculations should be radius-squared/watts >> >> >> I find it interesting that the products designed as jammers >> have ranges of "only" a few 10s of meters while a recent >> message here said 1/2 mile from a digital-radio link that was >> transmitting on 315 MHz. (aka designed for something else >> rather than as a jammer) >> >> Similarly, the Monterey Bay jammer wasn't trying to be a >> jammer, and it wiped out a huge area. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From bg at lysator.liu.se Mon Nov 16 06:27:03 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Mon, 16 Nov 2009 07:27:03 +0100 (CET) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <0767F9980C9944C79457D84BEC499933@d400> References: <4B003189.4050000@erols.com> <4B009C02.3000309@xtra.co.nz> <2303.12.6.201.222.1258331894.squirrel@popacctsnew.quik.com> <4B00B717.7020507@xtra.co.nz> <0767F9980C9944C79457D84BEC499933@d400> Message-ID: <52272.87.227.52.225.1258352823.squirrel@webmail.lysator.liu.se> > Bruce, > > I agree with your calculation and conclusion, as far as commercial > consumer > GPS receivers are concerned. > > A data sheet that was linked in a previous post for an aviation-grade > commercial GPS receiver indicated resistance to signals -30dBm at the > receiver input. That is quite considerable, and much better than the > hand-held consumer units (by 30dB?) I would be very surprised if "aviation-grade" receivers are better than your new average handheld Garmin. > I would expect planes and other potential "high value targets" to have > receivers of similar performance. I would expect the opposite, since important receivers - say for timing of power generation, timing of bankingsystems, etc typically runs forever often beeing 5 to ten years old before uppgrading. -- Bj?rn From die at dieconsulting.com Mon Nov 16 07:59:37 2009 From: die at dieconsulting.com (David I. Emery) Date: Mon, 16 Nov 2009 02:59:37 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <20091116033307.GA8612@pig.dieconsulting.com> References: <4B003189.4050000@erols.com> <4B00B717.7020507@xtra.co.nz> <0767F9980C9944C79457D84BEC499933@d400> <20091116033307.GA8612@pig.dieconsulting.com> Message-ID: <20091116075937.GA10760@pig.dieconsulting.com> On Sun, Nov 15, 2009 at 10:33:07PM -0500, David I. Emery wrote: > > LORAN C represents a viable (albeit not often deployed) backup > to time and frequency control and could be implemented in modern > hardware as a backup location service at reasonably low cost for those > applications where that is important enough. I might add that there ARE some regional solutions to the timing and frequency backup issue (time-nuts meat) that COULD be implemented pretty easily. One is locking ATSC TV signals to Cs standards backed by GPS. I am pretty sure that it would not take a lot of effort to adopt existing ATSC Tuner chip designs and maybe the actual current technology already available chips themselves to recover accurate time and frequency from a ATSC signal locked to a good standard. And TV transmitters are LOUD compared to GPS and therefor not so easily jammed on a wide area basis. I don't imagine the cost of Cs locking a few TV signals is all that high either... most of the gear can accept external frequency references and clocks... and already does to a considerable degree. Obviously if one needs time of day to high precision one needs to use a local GPS to determine the time offset of a TV signal as received at a particular site, but this should not change much provided the clock at the transmitter was really good. And the ATSC transport stream provides a rich channel for sending information about time offsets and other sync status on a real time basis... I suppose this could substitute for Loran as a regional backup for telecoms networks as protection against GPS denial... -- Dave Emery N1PRE/AE, die at dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." From phk at phk.freebsd.dk Mon Nov 16 08:10:17 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 16 Nov 2009 08:10:17 +0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: Your message of "Mon, 16 Nov 2009 07:27:03 +0100." <52272.87.227.52.225.1258352823.squirrel@webmail.lysator.liu.se> Message-ID: <53707.1258359017@critter.freebsd.dk> Various not so random notes: The power needed to jam GPS depends a lot on receiver state, during TTFF it takes virtually nothing. Therefore most "real" jammers will periodically blast at high power, to "dislodge" any locked receivers and then continue at low power to keep them off the signal. They are also built spectrum efficient, by emitting a signal designed specifically to interfere with GPS' spread-spectrum encoding, either by trying to lure the receivers to aim for the jammer (lowest power) or just by mimicking the worst kind of power for acquisition & tracking (higher power). Most receivers have hard-limiting inputs, so overload is a slightly more involved concept than for analog inputs, but it is still possible. The jammers which were quoted earlier are not "real jammers": they are just simple noise-sources, and long range is a negative sales parameter, because they are intended for "personal protection": a long range would increase the risk that they get detected. Their main customer base is drug-runners, fraudulent businessmen, infidel husbands and criminals sentenced to home-confinement with a GPS a ancle-bracelet. Many of those jammers does not work as well as advertised. Some of them are even "trojaned" and emit a signature signal for the benefit of law-enforcement. The infamous tv-preamp case was so efficient because it trippled the frequency of a local TV signal, due to instability, went into saturation/clipping and had a circular antenna with convenient dimensions to radiation of the resulting blanket of noise around the GPS frequency. Unfortunately, nobody tought about measuring its power-consumption or if they did, they didn't publish it. Given the kind of UHF transistors usually used in antenna-preamps, we are very likely talking no more than 1W. I an urban/hi-rise environment, havoc can be played with jammers that use glass facades as reflectors for the signal. The story about the "Mexican LORAN-C jammer" is instructive in how that complicates finding the trouble. GPS antennas on planes in the air do receive some help from being above it all, and pilots can still fly without GPS. The trouble starts once CATIII landings on GPS become routine. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From rk at timing-consultants.com Mon Nov 16 09:39:18 2009 From: rk at timing-consultants.com (Rob Kimberley) Date: Mon, 16 Nov 2009 09:39:18 -0000 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: <2294.12.6.201.222.1258331280.squirrel@popacctsnew.quik.com> Message-ID: GPS antennae are mounted top and bottom on tactical aircraft. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Francesco Ledda Sent: 16 November 2009 00:37 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Considering that the GPS antenna in aircrafts is mounted on top of fuselage, and that its radiation pattern is upward, it seems that a ground jammer will have an uphill battle. -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of J. Forster Sent: Sunday, November 15, 2009 6:28 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) Or even into MP3 players, iPods, laptops, or cell phones. Then they'd wander all over the place too. With the latter two hosts, they could even be controlled remotely and even be fairly powerful. Would you notice having to recharge your battery a bit more often? -John =========== > Magnus Danielson wrote: >> Chuck, >> >> Chuck Harris wrote: >>> What makes you think it needs to be CW, and cannot be pulsed and >>> chirped? >> >> May I roll in a noise jammer into the debate? > > Absolutely! They can be extremely power efficient. Raise the noise > floor in the vicinity of the receiver, and it is all done. > > Probably the easiest solution would be to take a PN source and use it > to drive a pulser that pulses a chirp oscillator. If you are feeling > really polite, you could put a bandpass filter on the thing to protect > other services. > >>> All it has to do is confuse the receiver enough so that you can't >>> trust its readings. >> >> Depends on the goal. For some strategies, blackout is the goal, for some >> getting the readings go haywire every once in a while suffice. > > Agreed! > > My 9V battery suggestion was for a localized blackout device. You only > have to make the receiver question each satellite's signal often enough > for it to rule it out. No way is CW necessary, or even desirable. > > As John suggested, someone (say the Chinese) could put these things in > battery operated stuffed animals, and set them up to jam a little bit > now and then. After Xmas, the GPS landscape would be littered with these > little stealth jammers, and willing supplicants to replace their > batteries. > > -Chuck > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13700 http://www.pctools.com/en/spyware-doctor-antivirus/ _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From dave at uk-ar.co.uk Mon Nov 16 13:59:45 2009 From: dave at uk-ar.co.uk (Dave Baxter) Date: Mon, 16 Nov 2009 13:59:45 -0000 Subject: [time-nuts] GPS Jamming? In-Reply-To: Message-ID: Hi. The "Monterey Bay" jammer, was indeed a UHF TV active antenna. But, it was hooting at about 1500MHz, that's what corrupted the GPS signals in that area. It's not unusual, there are many such documented cases from all round the globe of similar instances, and it's not just GPS systems getting hit either. A recent case in the UK, a digital TV set top box, was taking out the VHF comm's to a nearby local airport! Lucky there was an alternative channel to use, but it was found and "removed from service". As to "resistance to signals at the input" That's probably for one clean and stable carrier, like a local harmonic from a broadcast FM receiver's own local oscillator. I kid you not! It happens, and is again well documented in several cases, mostly in the US with one particular make of SUV, suffering more than most, the symptoms being that the built in sat-nav gave up, if you had the FM radio tuned to one particular station! It is all to trivial to successfully jam a spread spectrum signal.. You just blot it out with another wide band signal, such as rapid sweeping, or broadband noise. Some systems are also all to vulnerable to pulse type interference too (Terrestrial DTV for one! OK, so not "true" spread spectrum, but......) The UK military often notify "other users" of "GPS Jamming Exercises" in various places at odd times, all around the UK. I don't know the purpose of such "exercises" other than to perhaps prevent squaddies out on a navigation training jaunt, not to cheat with personal GPS devices? But I do know that the result varies from total loss of signals as the receiver sees things, to a fix of sorts, but way off from where it should be. No doubt also screwing with any pps timing if that was in use. (to keep tenuously on topic?) Unintentional emissions from electronic systems are one of the worst things to find and fix. Regards. Dave B. From EWKehren at aol.com Mon Nov 16 15:08:16 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 16 Nov 2009 10:08:16 EST Subject: [time-nuts] Dual Mixer Message-ID: As part of the Dual Mixer project I am looking for a source of reasonably priced 80 MHz Xtal's in HC 49 holder. International Crystal wants $12 in fifty Qty. In my opinion to high. Any help will be appreciated. Thanks Bert Kehren From danrae at verizon.net Mon Nov 16 15:15:24 2009 From: danrae at verizon.net (Dan Rae) Date: Mon, 16 Nov 2009 07:15:24 -0800 Subject: [time-nuts] Dual Mixer In-Reply-To: References: Message-ID: <4B016C8C.8050009@verizon.net> EWKehren at aol.com wrote: > As part of the Dual Mixer project I am looking for a source of reasonably > priced 80 MHz Xtal's in HC 49 holder. International Crystal wants $12 in > fifty Qty. In my opinion to high. Any help will be appreciated. Thanks Bert > Kehren > How about XC1567CT-ND from Digikey, around $5 each? http://www.ecsxtal.com/store/pdf/ecx-2236.pdf Dan From wpxs472 at gmail.com Mon Nov 16 15:17:52 2009 From: wpxs472 at gmail.com (John Green) Date: Mon, 16 Nov 2009 09:17:52 -0600 Subject: [time-nuts] Jamming GPS Message-ID: All the discussion regarding jamming GPS has been very interesting. Because it is spread spectrum, I always assumed it would be difficult to jam GPS. The Monterey Bay incident indicates that it is extremely easy to jam GPS. So, as soon as another project is out of the way, I intend to do some experiments, more of a practical than scientific nature. I have a Z3801 and Tbolt to start with. I would also like to experiment with a hand held and a GPS enabled cellphone. To prevent unintended interference, signal levels will have to be carefully controlled and transmission time will have to be kept short. I want to try CW as well as modulations of varying types. Any suggestions as to the most effective modulation type to try? From james.p.lux at jpl.nasa.gov Mon Nov 16 15:22:54 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Mon, 16 Nov 2009 07:22:54 -0800 Subject: [time-nuts] Jamming GPS In-Reply-To: Message-ID: On 11/16/09 7:17 AM, "John Green" wrote: > All the discussion regarding jamming GPS has been very interesting. Because > it is spread spectrum, I always assumed it would be difficult to jam GPS. > The Monterey Bay incident indicates that it is extremely easy to jam GPS. > So, as soon as another project is out of the way, I intend to do some > experiments, more of a practical than scientific nature. I have a Z3801 and > Tbolt to start with. I would also like to experiment with a hand held and a > GPS enabled cellphone. To prevent unintended interference, signal levels > will have to be carefully controlled and transmission time will have to be > kept short. I want to try CW as well as modulations of varying types. Any > suggestions as to the most effective modulation type to try? > Do you want to jam during acquisition or during track? Your cellphone probably has what's called an "assisted GPS" receiver, where the cell system tells the receiver in the phone initial estimates of code phase as well as which satellites are in view. That is, a lot of the initial acquisition steps are already done. (it reduces nanojoules/fix dramatically, and that's important in a cellphone.. And it makes the receiver cheaper and that's important too) Most inexpensive receivers use a single bit quantizer, so they're quite vulnerable to a CW signal at the right frequency, because that will dominate over the received spread signal, especially before code acquisition. From EWKehren at aol.com Mon Nov 16 15:20:25 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 16 Nov 2009 10:20:25 EST Subject: [time-nuts] Jamming GPS Message-ID: Having followed the discussions on GPS jamming I have to question if this is a safe forum for such open info. In the wrong hands it allows the wrong people to cause serious problems. Bert Kehren In a message dated 11/16/2009 10:18:39 A.M. Eastern Standard Time, wpxs472 at gmail.com writes: All the discussion regarding jamming GPS has been very interesting. Because it is spread spectrum, I always assumed it would be difficult to jam GPS. The Monterey Bay incident indicates that it is extremely easy to jam GPS. So, as soon as another project is out of the way, I intend to do some experiments, more of a practical than scientific nature. I have a Z3801 and Tbolt to start with. I would also like to experiment with a hand held and a GPS enabled cellphone. To prevent unintended interference, signal levels will have to be carefully controlled and transmission time will have to be kept short. I want to try CW as well as modulations of varying types. Any suggestions as to the most effective modulation type to try? _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From ssybert at kb1fxy.us Mon Nov 16 15:39:32 2009 From: ssybert at kb1fxy.us (Scott A Sybert) Date: Mon, 16 Nov 2009 07:39:32 -0800 Subject: [time-nuts] Jamming GPS References: Message-ID: <15D717421F0B004A82877D8DFEDF912B058B56@ex14.hostedexchange.local> I can't think of a better place for the technical users of a system to discuss and test the vulnerabilities of the system in which they depend on. If the system is vulnerable, it should be well known and redundancy should be made available. A false sense of security is no security at all. If there are concerns lets discuss and test them and let the cards fall where they may. If the outcome is GPS is at tremendous risk because the 9V attack is REAL and EFFECTIVE, so be it. We're better off knowing this info now and preparing for it than finding out the hard way when the bad guy figures it out first. This entire discussion stemmed from the 2010 EOL of LORAN. I think we've all agreed GPS IS vulnerable. It's just to what extent and how easily interruption can be caused. Like I said yesterday, we're not covering anything a true enemy hasn't discussed. Building experimental jammers in our basements for educational purposes is easily dwarfed by the resources of a serious attacker (i.e. foreign government, terrorist organization, etc). Scott ________________________________ From: time-nuts-bounces at febo.com on behalf of EWKehren at aol.com Sent: Mon 11/16/2009 10:20 AM To: time-nuts at febo.com Subject: Re: [time-nuts] Jamming GPS Having followed the discussions on GPS jamming I have to question if this is a safe forum for such open info. In the wrong hands it allows the wrong people to cause serious problems. Bert Kehren In a message dated 11/16/2009 10:18:39 A.M. Eastern Standard Time, wpxs472 at gmail.com writes: All the discussion regarding jamming GPS has been very interesting. Because it is spread spectrum, I always assumed it would be difficult to jam GPS. The Monterey Bay incident indicates that it is extremely easy to jam GPS. So, as soon as another project is out of the way, I intend to do some experiments, more of a practical than scientific nature. I have a Z3801 and Tbolt to start with. I would also like to experiment with a hand held and a GPS enabled cellphone. To prevent unintended interference, signal levels will have to be carefully controlled and transmission time will have to be kept short. I want to try CW as well as modulations of varying types. Any suggestions as to the most effective modulation type to try? _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From alan.melia at btinternet.com Mon Nov 16 15:41:37 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 16 Nov 2009 15:41:37 -0000 Subject: [time-nuts] Dual Mixer References: Message-ID: <002d01ca66d3$6315b4e0$0900a8c0@lark> Mmmm I think you are comparing with cheapie "computer grade crystals". That price of $12 is pretty much in line with charges for "made to measure" crystals in the UK at ?7 to ?8 (GBP) each (3rd or 5th OT) some discount for quantities over 10. These would be on spec and of commercial quality, suitable for instance for radio applications. Computer grade cystals can be ok for some applications but are generally of a much lower standard of quality. There is much lower demand for crystals since all radio use sythersisers now and a lot of companies have gone out of business because to total market is much smaller. If cheapies will suit and 80MHz is not available you could always use 40MHz which I think is in the range and use a low noise doubler ?? Alan G3NYK ----- Original Message ----- From: To: Sent: Monday, November 16, 2009 3:08 PM Subject: [time-nuts] Dual Mixer > As part of the Dual Mixer project I am looking for a source of reasonably > priced 80 MHz Xtal's in HC 49 holder. International Crystal wants $12 in > fifty Qty. In my opinion to high. Any help will be appreciated. Thanks Bert > Kehren > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From geo at drbertges.de Mon Nov 16 14:42:16 2009 From: geo at drbertges.de (geo at drbertges.de) Date: Mon, 16 Nov 2009 15:42:16 +0100 Subject: [time-nuts] Jamming GPS Message-ID: <20091116144216.36FF111F7E@drbertges.de> Hi, for nonmilitary GNSS receiver, you do not need a wide band signal for jamming. You only need a carrier with a signal power, sufficient to screw down the AGC in the GNSS receiver's front end. ... and as a purpose for a military jamming exercise ... think of the successfull detection of a jammer or the transmission of simulated signals with a higher signal power as the satellite signals (using the "near/far" problem of pseudolite/satellite signals). I totally agree ... unintended emissions are awfull problems ! Your GNSS receiver (better the AGC !) will not only "accept" signals on the L1 frequency, but on all the image frequencies of the mixer stages in the RF front end. The modulation type doesn't matter ... it's only the signal power ;-) Best regards Martin From phk at phk.freebsd.dk Mon Nov 16 15:52:31 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 16 Nov 2009 15:52:31 +0000 Subject: [time-nuts] GPS Jamming? In-Reply-To: Your message of "Mon, 16 Nov 2009 13:59:45 GMT." Message-ID: <37688.1258386751@critter.freebsd.dk> In message , "Dav e Baxter" writes: >The UK military often notify "other users" of "GPS Jamming Exercises" in >various places at odd times, all around the UK. I don't know the >purpose of such "exercises" other than to perhaps prevent squaddies out >on a navigation training jaunt, not to cheat with personal GPS devices? Most of these exercises have "location of GPS jammer" as objective :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From phk at phk.freebsd.dk Mon Nov 16 15:53:25 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 16 Nov 2009 15:53:25 +0000 Subject: [time-nuts] Jamming GPS In-Reply-To: Your message of "Mon, 16 Nov 2009 09:17:52 CST." Message-ID: <37708.1258386805@critter.freebsd.dk> In message , John Green writes: >Any suggestions as to the most effective modulation type to try? Pseudo-random 50Hz FSK ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From msa at latt.net Mon Nov 16 16:00:26 2009 From: msa at latt.net (Majdi S. Abbas) Date: Mon, 16 Nov 2009 09:00:26 -0700 Subject: [time-nuts] Jamming GPS In-Reply-To: References: Message-ID: <20091116160026.GA26793@puck.nether.net> On Mon, Nov 16, 2009 at 10:20:25AM -0500, EWKehren at aol.com wrote: > Having followed the discussions on GPS jamming I have to question if this > is a safe forum for such open info. In the wrong hands it allows the wrong > people to cause serious problems. Bert Kehren There have been published designs on the Internet for the last decade or so, and there are plenty of (illegal, but common) GPS jammers that pop up on eBay and the like. Security through obscurity doesn't work. The hardware is inexpensive and commercially available. Now, whether or not the subject is on-topic at this point, is another question entirely. 73, Majdi, N0RMZ From EWKehren at aol.com Mon Nov 16 16:14:42 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 16 Nov 2009 11:14:42 EST Subject: [time-nuts] Dual Mixer Message-ID: Thanks for the info. I can use 40 MHz since I divide it down to 5 and 10 MHz after pulling it to get the proper offset. I prefer 80 because I have tests with a 100 MHz Xtal with great results. Thanks again Bert Kehren In a message dated 11/16/2009 10:43:05 A.M. Eastern Standard Time, alan.melia at btinternet.com writes: Mmmm I think you are comparing with cheapie "computer grade crystals". That price of $12 is pretty much in line with charges for "made to measure" crystals in the UK at ?7 to ?8 (GBP) each (3rd or 5th OT) some discount for quantities over 10. These would be on spec and of commercial quality, suitable for instance for radio applications. Computer grade cystals can be ok for some applications but are generally of a much lower standard of quality. There is much lower demand for crystals since all radio use sythersisers now and a lot of companies have gone out of business because to total market is much smaller. If cheapies will suit and 80MHz is not available you could always use 40MHz which I think is in the range and use a low noise doubler ?? Alan G3NYK ----- Original Message ----- From: To: Sent: Monday, November 16, 2009 3:08 PM Subject: [time-nuts] Dual Mixer > As part of the Dual Mixer project I am looking for a source of reasonably > priced 80 MHz Xtal's in HC 49 holder. International Crystal wants $12 in > fifty Qty. In my opinion to high. Any help will be appreciated. Thanks Bert > Kehren > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From wpxs472 at gmail.com Mon Nov 16 16:40:07 2009 From: wpxs472 at gmail.com (John Green) Date: Mon, 16 Nov 2009 10:40:07 -0600 Subject: [time-nuts] 80 MHz Crystal Message-ID: Do you need 80 MHz exactly? I have a number of tcxos around that frequency but I doubt any that are exactly 80 MHz. By the way, $12 for a good crystal doesn't sound all that high. Seems the last ones I bought from ICM for channel elements which aren't all that precise, were close to $20. From garnere at gmail.com Mon Nov 16 16:44:21 2009 From: garnere at gmail.com (Eric Garner) Date: Mon, 16 Nov 2009 08:44:21 -0800 Subject: [time-nuts] Loran C shutdown In-Reply-To: <20091113221126.625193@nectarine> References: <20091113221126.625193@nectarine> Message-ID: Does anyone know if there is any organized attempt to save LORAN? -Eric On Fri, Nov 13, 2009 at 7:11 PM, Joe Geller wrote: > The Coast Guard has always been stretched very thin with limited resources > for many missions. ?The saying was, every year we do more and more with less and less. > I served in the late 70s as an electronics technician, EE, and later after Navy > flight school, flying air rescue into the 80s. > > I was lucky to spend some time at two of the research labs, the electronics > engineering center (EECEN) in Wildwood, NJ and later the electrical engineering laboratory (EELAB) in > Alexandria, VA. ?At EELAB, I worked in other areas, but a lot of the LORAN work > was done there. ?I remember, even back then, that some of the LORAN guys > were searching hobby electronics suppliers to find obsolete chips they needed to keep the > LORAN system going. I think those were LORAN C boards too, although not sure. > Some new LORAN boards were being developed at the next bench over that used 6502 > micros (I got to go to the micro class with the LORAN guys). > > Flying HU-25A Falcon jets (modified Falcon 200s that we got in 1982) across the Gulf of Mexico for > some years, we had a gyro inertial system (which took some 20 minutes to align), LORAN C, > and all the standard aviation navigation gear, ADF, VOR, DME, and TACAN. ?The > Collins ?RNAV? system used all inputs to develop position information. ?As I recall, > once we got hundreds of miles out into the gulf, all we had left was the inertial system > (and paper charts and aluminum slide rules and later my hp-41CV with nav > equations, when the RNAV when out). ?What we would have given for a GPS! > > Oh well, at least on the bright side, maybe some of those hp clocks will start to > show up on the surplus market. > > There is a picture of the Falcon at: > http://www.aero-web.org/database/aircraft/getimage.htm?id=15047 > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- --Eric _________________________________________ Eric Garner From phk at phk.freebsd.dk Mon Nov 16 16:56:51 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 16 Nov 2009 16:56:51 +0000 Subject: [time-nuts] Loran C shutdown In-Reply-To: Your message of "Mon, 16 Nov 2009 08:44:21 PST." Message-ID: <50441.1258390611@critter.freebsd.dk> In message , Eric Garner writes: >Does anyone know if there is any organized attempt to save LORAN? loran.org would be the place to ask. People who went to ILA38 might be good to contact. The problem is that nobody loves LORAN enough to fight for it, despite all the sound arguments about its suitability as GPS backup. Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From frledda at verizon.net Mon Nov 16 16:57:28 2009 From: frledda at verizon.net (Francesco Ledda) Date: Mon, 16 Nov 2009 10:57:28 -0600 Subject: [time-nuts] Loran C shutdown In-Reply-To: References: <20091113221126.625193@nectarine> Message-ID: <004601ca66dd$e1942b30$a4bc8190$@net> AOPA -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Eric Garner Sent: Monday, November 16, 2009 10:44 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Loran C shutdown Does anyone know if there is any organized attempt to save LORAN? -Eric On Fri, Nov 13, 2009 at 7:11 PM, Joe Geller wrote: > The Coast Guard has always been stretched very thin with limited resources > for many missions. ?The saying was, every year we do more and more with less and less. > I served in the late 70s as an electronics technician, EE, and later after Navy > flight school, flying air rescue into the 80s. > > I was lucky to spend some time at two of the research labs, the electronics > engineering center (EECEN) in Wildwood, NJ and later the electrical engineering laboratory (EELAB) in > Alexandria, VA. ?At EELAB, I worked in other areas, but a lot of the LORAN work > was done there. ?I remember, even back then, that some of the LORAN guys > were searching hobby electronics suppliers to find obsolete chips they needed to keep the > LORAN system going. I think those were LORAN C boards too, although not sure. > Some new LORAN boards were being developed at the next bench over that used 6502 > micros (I got to go to the micro class with the LORAN guys). > > Flying HU-25A Falcon jets (modified Falcon 200s that we got in 1982) across the Gulf of Mexico for > some years, we had a gyro inertial system (which took some 20 minutes to align), LORAN C, > and all the standard aviation navigation gear, ADF, VOR, DME, and TACAN. ?The > Collins ?RNAV? system used all inputs to develop position information.. ?As I recall, > once we got hundreds of miles out into the gulf, all we had left was the inertial system > (and paper charts and aluminum slide rules and later my hp-41CV with nav > equations, when the RNAV when out). ?What we would have given for a GPS! > > Oh well, at least on the bright side, maybe some of those hp clocks will start to > show up on the surplus market. > > There is a picture of the Falcon at: > http://www.aero-web.org/database/aircraft/getimage.htm?id=15047 > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- --Eric _________________________________________ Eric Garner _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13710 http://www.pctools.com/en/spyware-doctor-antivirus/ E-mail message checked by Spyware Doctor (6.0.0.386) Database version: 5.13710 http://www.pctools.com/en/spyware-doctor-antivirus/ From jfor at quik.com Mon Nov 16 16:59:29 2009 From: jfor at quik.com (J. Forster) Date: Mon, 16 Nov 2009 08:59:29 -0800 (PST) Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: Message-ID: <1170.12.6.201.56.1258390769.squirrel@popacctsnew.quik.com> From jmfranke at cox.net Mon Nov 16 17:36:01 2009 From: jmfranke at cox.net (jmfranke at cox.net) Date: Mon, 16 Nov 2009 12:36:01 -0500 Subject: [time-nuts] Jamming GPS In-Reply-To: Message-ID: <20091116123601.BQAUS.980618.imail@eastrmwml43> For testing, I would suggest using a directional coupler in the antenna lead to reduce the chances for unwanted radiation. John WA4WDL ---- John Green wrote: > All the discussion regarding jamming GPS has been very interesting. Because > it is spread spectrum, I always assumed it would be difficult to jam GPS. > The Monterey Bay incident indicates that it is extremely easy to jam GPS. > So, as soon as another project is out of the way, I intend to do some > experiments, more of a practical than scientific nature. I have a Z3801 and > Tbolt to start with. I would also like to experiment with a hand held and a > GPS enabled cellphone. To prevent unintended interference, signal levels > will have to be carefully controlled and transmission time will have to be > kept short. I want to try CW as well as modulations of varying types. Any > suggestions as to the most effective modulation type to try? > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From dave at uk-ar.co.uk Mon Nov 16 17:46:57 2009 From: dave at uk-ar.co.uk (Dave Baxter) Date: Mon, 16 Nov 2009 17:46:57 -0000 Subject: [time-nuts] [OT] repeater jammer In-Reply-To: Message-ID: Repeater jammer? Hmm.... A single semi resonant antenna, with a small signal diode at it's feed (doesn't even need to be a VHF type!) Then feed it from a 600kHz oscillator (or whatever the repeater offset frequency is). Running off a suitable battery, build it small, throw it in a tree near the repeater, wait for the mayhem to begin. Better still, make half a dozen of them and scatter them around near the repeater site, within half a k should do. They don't create a big signal on the input, just enough to keep the box busy and 'P' off people, heterodynes all over the place... Difficult to DF too, as most DF kit will be swamped by the repeaters normal output level. Turn the box off, and the QRM goes away, so you cant even DF the blasted things in the quiet. If you felt 'really' malicious, you could put a simple random timer in there too. Total chaos! That's what some bar stewards have done here in the UK in the past. Then there are the sophisticated ones, with two FET's in them! They can be placed some miles away, for added inconvenience. There has even been at least one with an "added ingredient" that needed army types to sort out! It was a dud thankfully by the time it was found (by a bloke walking his dog!) So, you can see that there is nothing new about any of this weird stuff. The cheapest GPS jammer, is one of the common (but now ilegal, in the UK anyway) re-radiating "GPS extenders", so you can run a handheld GPS RX (with no external antenna facility) in a car with a heated or other metalic coating on the 'screen. If they see their own output, you can nuke all civilian GPS activity for over a 1/4 mile radius! Dave B. > A *much* more effective and cheap strategy is a repeater jammer.. > Receive > the signal and retransmit it: two antennas and an amplifier. The > victim sees > the delayed retransmitted signal at a higher level than the direct > one. It's > sort of like creating fake multipath interference. No need for PN > generators, oscillators, etc. > > Granted, a smart receiver that *understands* the relationship > between SV to > user geometry and doppler can beat it (because the carrier phase and > PN > phase of the repeated signal won't be consistent with the geometry), > but the > run of the mill PN tracking loop probably won't. From jim.cotton at wmich.edu Mon Nov 16 18:00:02 2009 From: jim.cotton at wmich.edu (Jim Cotton) Date: Mon, 16 Nov 2009 13:00:02 -0500 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <20091116012140.GB5736@pig.dieconsulting.com> References: <4B008F3B.8030300@erols.com> <20091116012140.GB5736@pig.dieconsulting.com> Message-ID: <4B019322.6090009@wmich.edu> Just a data point about timing applications and jamming.... The HP 8935A CDMA base station test set when first released covered 0-1.0 Ghz and 1.7-2.0 Ghz on the spectrum analyzer function. It was expanded to 1.4-2.0 Ghz on the upper range expressly for doing GPS noise surveys of sites, to locate local interference. Jim Cotton n8qoh From EWKehren at aol.com Mon Nov 16 20:25:26 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Mon, 16 Nov 2009 15:25:26 EST Subject: [time-nuts] 80 MHz Crystal Message-ID: It is not high if you only want to buy one or two. But as part of the Dual Mixer I am sensetive to price because I want to make it as affordable as possible willing to buy in bulk and I can buy good quality 100 MHZ Xtals from Conrad in Germany for about a $. They have to be right on because they will be in a PLL and be pulled slightly to generate the 1 Hz and 10 Hz offset at 5 and 10 MHz. Thanks again. Bert Kehren In a message dated 11/16/2009 11:41:10 A.M. Eastern Standard Time, wpxs472 at gmail.com writes: Do you need 80 MHz exactly? I have a number of tcxos around that frequency but I doubt any that are exactly 80 MHz. By the way, $12 for a good crystal doesn't sound all that high. Seems the last ones I bought from ICM for channel elements which aren't all that precise, were close to $20. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Mon Nov 16 20:55:51 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 16 Nov 2009 21:55:51 +0100 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: References: Message-ID: <4B01BC57.5090607@rubidium.dyndns.org> Lux, Jim (337C) wrote: > A *much* more effective and cheap strategy is a repeater jammer.. Receive > the signal and retransmit it: two antennas and an amplifier. The victim sees > the delayed retransmitted signal at a higher level than the direct one. It's > sort of like creating fake multipath interference. No need for PN > generators, oscillators, etc. The delay attack is known (it's actually more of a spoofing attack), but most jamming uses just simple CW or noise signals. A problem with the delay attack is that you have a risc of creating a feedback loop which creates an unstable oscillation, which may or may not be what you would like. Among other things, directional finding on an oscillation is much easier than the delayed signal. However, a good hint is to use a directional L1 antenna and point it to the signal and just hook a receiver up and the position you have is that of the attackers antenna. Again that reveals the position. I guess this is why the attack isn't particularly used. > Granted, a smart receiver that *understands* the relationship between SV to > user geometry and doppler can beat it (because the carrier phase and PN > phase of the repeated signal won't be consistent with the geometry), but the > run of the mill PN tracking loop probably won't. Actually, even the simpler receivers has some resistance to it, the higher amplitude is the main problem. > Most inexpensive receivers use a single bit sampler, so a suitable CW tone > could also probably jam it effectively, but might require some knowledge of > the victim receiver to pick an appropriate frequency (i.e. You'd need to > know the sampling rate.) The CW attack is well known and has been analyzed fairly deeply. You don't need the sampling rate to make it efficient. The one-bit receiver is dead in the sea compared to even 1.5 bit receivers with suitable AGC loop detection. Cheers, Magnus From robert8rpi at yahoo.co.uk Mon Nov 16 21:31:43 2009 From: robert8rpi at yahoo.co.uk (Robert Atkinson) Date: Mon, 16 Nov 2009 21:31:43 +0000 (GMT) Subject: [time-nuts] Jamming GPS In-Reply-To: Message-ID: <288070.19264.qm@web27106.mail.ukl.yahoo.com> Bit older but an interesting Thesis on jamming. http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA361736&Location=U2&doc=GetTRDoc.pdf or google "Analysis of Radio Frequency Interference Effects on a Modern Coarse Acquisition Code Global Positioning System" ? Robert G8RPI. --- On Mon, 16/11/09, John Green wrote: From: John Green Subject: [time-nuts] Jamming GPS To: time-nuts at febo.com Date: Monday, 16 November, 2009, 15:17 All the discussion regarding jamming GPS has been very interesting. Because it is spread spectrum, I always assumed it would be difficult to jam GPS. The Monterey Bay incident indicates that it is extremely easy to jam GPS. So, as soon as another project is out of the way, I intend to do some experiments, more of a practical than scientific nature. I have a Z3801 and Tbolt to start with. I would also like to experiment with a hand held and a GPS enabled cellphone. To prevent unintended interference, signal levels will have to be carefully controlled and transmission time will have to be kept short. I want to try CW as well as modulations of varying types. Any suggestions as to the most effective modulation type to try? _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From david.bengtson at gmail.com Mon Nov 16 22:56:19 2009 From: david.bengtson at gmail.com (David Bengtson) Date: Mon, 16 Nov 2009 17:56:19 -0500 Subject: [time-nuts] Lady Heather Serial receive Error 0x2 In-Reply-To: References: Message-ID: Hi All I finally managed to get some time to figure this out. I was using a usb-serial interface with the FTDI chipset, and I had to tweak two parameters to get it working. First, I had to tell the driver that I didn't have a serial mouse (Serial enumnerator checkbox) and the second thing was to tweak the serial buffer. It was set to 4k, which was too large. I changed that to 1k, and it's been running for ~ 20 hours happily. Dave On Tue, Nov 3, 2009 at 9:53 PM, David Bengtson wrote: > Hi All: > > I'm running what I believe to be the latest version of Lady Heather on > a Windows XP laptop. I'm using a USB-Serial interface, and I'm getting > this error after about 15 to 20 minutes of data taking. I haven't seen > any recent discussion on this problem, I'm curious to know if anyone > else has seen this, and if they've figured it out. Once the error > message shows up, I quit out and restart the app, and it works fine. > I'm starting it with a shortcut ?"C:\Program > Files\Heather\heather.exe" /7 to point it at the com7 serial porty. > > Thanks > > > Dave > From jmiles at pop.net Tue Nov 17 00:51:02 2009 From: jmiles at pop.net (John Miles) Date: Mon, 16 Nov 2009 16:51:02 -0800 Subject: [time-nuts] Lady Heather Serial receive Error 0x2 In-Reply-To: Message-ID: The upcoming 3.0 version will have much better serial code (i.e., Mark's, rather than mine) but yes, it may still be vulnerable to the Windows serial-mouse lameness. I'm not sure why the FIFO buffer size should have mattered, though. If any other information on that comes to light, I'd be curious to hear about it. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of David Bengtson > Sent: Monday, November 16, 2009 2:56 PM > To: time-nuts at febo.com > Subject: Re: [time-nuts] Lady Heather Serial receive Error 0x2 > > > Hi All > > I finally managed to get some time to figure this out. I was using a > usb-serial interface with the FTDI chipset, and I had to tweak two > parameters to get it working. First, I had to tell the driver that I > didn't have a serial mouse (Serial enumnerator checkbox) and the > second thing was to tweak the serial buffer. It was set to 4k, which > was too large. I changed that to 1k, and it's been running for ~ 20 > hours happily. > > Dave > > On Tue, Nov 3, 2009 at 9:53 PM, David Bengtson > wrote: > > Hi All: > > > > I'm running what I believe to be the latest version of Lady Heather on > > a Windows XP laptop. I'm using a USB-Serial interface, and I'm getting > > this error after about 15 to 20 minutes of data taking. I haven't seen > > any recent discussion on this problem, I'm curious to know if anyone > > else has seen this, and if they've figured it out. Once the error > > message shows up, I quit out and restart the app, and it works fine. > > I'm starting it with a shortcut ?"C:\Program > > Files\Heather\heather.exe" /7 to point it at the com7 serial porty. > > > > Thanks > > > > > > Dave > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From david.bengtson at gmail.com Tue Nov 17 02:51:35 2009 From: david.bengtson at gmail.com (David Bengtson) Date: Mon, 16 Nov 2009 21:51:35 -0500 Subject: [time-nuts] Lady Heather Serial receive Error 0x2 In-Reply-To: References: Message-ID: I based this on some troubleshooting notes on the FDTI web site, and they mentioned that devices that send lot's of short messages, as well as slow devices, tend to have problems with a 4k buffer. I tried it, and it's now working. Not sure I can bring much more to the table on this one. Dave On Mon, Nov 16, 2009 at 7:51 PM, John Miles wrote: > The upcoming 3.0 version will have much better serial code (i.e., Mark's, > rather than mine) but yes, it may still be vulnerable to the Windows > serial-mouse lameness. ?I'm not sure why the FIFO buffer size should have > mattered, though. ?If any other information on that comes to light, I'd be > curious to hear about it. > > -- john, KE5FX > >> -----Original Message----- >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On >> Behalf Of David Bengtson >> Sent: Monday, November 16, 2009 2:56 PM >> To: time-nuts at febo.com >> Subject: Re: [time-nuts] Lady Heather Serial receive Error 0x2 >> >> >> Hi All >> >> I finally managed to get some time to figure this out. I was using a >> usb-serial interface with the FTDI chipset, and I had to tweak two >> parameters to get it working. First, I had to tell the driver that I >> didn't have a serial mouse (Serial enumnerator checkbox) and the >> second thing was to tweak the serial buffer. It was set to 4k, which >> was too large. I changed that to 1k, and it's been running for ~ 20 >> hours happily. >> >> Dave >> >> On Tue, Nov 3, 2009 at 9:53 PM, David Bengtson >> wrote: >> > Hi All: >> > >> > I'm running what I believe to be the latest version of Lady Heather on >> > a Windows XP laptop. I'm using a USB-Serial interface, and I'm getting >> > this error after about 15 to 20 minutes of data taking. I haven't seen >> > any recent discussion on this problem, I'm curious to know if anyone >> > else has seen this, and if they've figured it out. Once the error >> > message shows up, I quit out and restart the app, and it works fine. >> > I'm starting it with a shortcut ?"C:\Program >> > Files\Heather\heather.exe" /7 to point it at the com7 serial porty. >> > >> > Thanks >> > >> > >> > Dave >> > >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From sar10538 at gmail.com Tue Nov 17 03:18:28 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Tue, 17 Nov 2009 16:18:28 +1300 Subject: [time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy) In-Reply-To: <72B8FB46D87A4CF2A12632F40082FEFE@d400> References: <4B00A4C1.5030909@rubidium.dyndns.org> <72B8FB46D87A4CF2A12632F40082FEFE@d400> Message-ID: <1231b6a80911161918u8a730d4ib71fc93b0eddd8cf@mail.gmail.com> 2009/11/16 Didier Juges : > Not all GPSs are on airplanes, but those I am really worried about are. > > I don't care if the GPS receiver in my cell phone stops working in some > locations, it does not work everywhere to begin with (like in the house, I > can't use it to find the bathroom in the dark...), but I worry that the one > guiding a missile or a fighter plane might not work. I also worry that the > one abord a large passenger aircraft might not work. Most of those that are > stationary or move on the ground or on water, I am not too worried about. And I'm really worried about statements like this that seem to indicate just how vulnerable we are if something seeming as fragile as GPS is compromised. People found the bathroom, drove from place to place and flew vast distances without GPS in the past but now have we taken a step too far. Surely all commercial and non-commercial pilots are able to navigate without such systems, this must be part of their training and are people not driving round with a set of maps in the glove compartment any more. If Starbucks is really reliant on GPS as a means for getting it's customers, perhaps they should review their business model. > For instance, the local garbage pickup people use GPS to locate the houses > of customers who have unusual (large or unsafe, or possibly contaminating) > garbage to pickup. I have had a dead TV on the side of my house for 3 weeks, > three times I called and 3 times they missed it because the GPS guided them > to my front door (my normal mailing address), but I live on a corner lot and > the garbage pickup is on the side of the house, by the garage. If that > particular GPS receiver stopped working and forced the employees to look > around, it would not bother me (the TV ended up in the trash can. After 3 > times and 3 weeks, I assumed I had done a reasonable attempt at avoiding > putting too much lead in the garbage, and it had to go.) Maybe your local garbage company should look at increasing the intelligence level requirements in it's recruitment process. Surely they could have looked around a bit to find it or were they lazy and gave up when the item was not at the exact spot as recorded by the GPS. That is surely a ludicrous system if you ask me. Perhaps the guys need more training, a course in map reading and the inclusion of maps in the vehicle. Steve > Didier > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Magnus Danielson >> Sent: Sunday, November 15, 2009 7:03 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] The Demise of LORAN (was Re: >> Reference oscillator accuracy) >> >> Francesco Ledda wrote: >> > Considering that the GPS antenna in aircrafts is mounted on top of >> > fuselage, and that its radiation pattern is upward, it seems that a >> > ground jammer will have an uphill battle. >> >> Not all GPS receivers is sitting on flying airplanes. Far from it. >> >> Cheers, >> Magnus >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, >> go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. From magnus at rubidium.dyndns.org Tue Nov 17 08:57:02 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 17 Nov 2009 09:57:02 +0100 Subject: [time-nuts] Lady Heather Serial receive Error 0x2 In-Reply-To: References: Message-ID: <4B02655E.9000608@rubidium.dyndns.org> David, David Bengtson wrote: > I based this on some troubleshooting notes on the FDTI web site, and > they mentioned that devices that send lot's of short messages, as well > as slow devices, tend to have problems with a 4k buffer. I tried it, > and it's now working. Not sure I can bring much more to the table on > this one. In their Technical Note 103 they write: 2 Bulk Data Transfers FTDI devices transfer data using USB Bulk transfers. The most efficient way to conduct USB bulk transfers is in large chunks. FTDI devices are bi-directional and can therefore both send and receive data across a USB connection. Sending data and receiving data will be considered as separate cases. 2.1 Sending Data When writing data to an FTDI device, as much data as possible should be buffered in the application and written to the device in a single write function call (either WriteFile for a VCP application using the Win32 API, FT_Write if using the D2XX classic interface or FT_WriteFile if using the D2XX FT_W32 interface). The result of this is that the data will be written to the device with 64 bytes per USB packet. If data were to be written in small amounts or even individual bytes as many applications written for legacy serial ports do, the USB bulk transfer protocol would only be able to transfer 1 byte per USB packet. This method is not efficient when employing USB bulk transfers and performance will be greatly diminished. For the receive data (which is more elaborately described) please see for yourselves at http://www.ftdichip.com/Documents/TechnicalNotes/TN_103_FTDI_USB_Data_Transfer_Efficiency%28FT_000097%29.pdf Cheers, Magnus From dave at uk-ar.co.uk Tue Nov 17 09:18:38 2009 From: dave at uk-ar.co.uk (Dave Baxter) Date: Tue, 17 Nov 2009 09:18:38 -0000 Subject: [time-nuts] Lady Heather Serial receive Error 0x2 In-Reply-To: Message-ID: Hi. In your LH shortcut, if you haven't already, you may want to make the "Start in:" setting, to be the same folder path, as the .exe your invoking with the shortcut. That can often (depending on what other files the .exe needs) make a big difference to performance and stability. Right click the shortcut, select properties, and it's the "Start in:" parameter. It makes a big difference if you are running Win16 programs too. They become much more stable! If nothing else, it'll force windows to look in it's own folder first for any needed resources, before searching the machines 'search path' etc. Of course, the app can specify the full path to the resource too if needed. When an app wants to load a DLL for example, if it is called by name only, the first place the system looks, is in the same folder as the calling app, then the windows system32/system folders, then the search path. (I cant remember if the DLL Cache is looked at before or after the system folders.) You can prove that with multiple DLL's of the same name in critical places, that each do nothing other than popup a message dialog (each message being unique to each DLL.) Quite enlightening to do that sort of thing at times, then you begin to understand "DLL Hell" if noting else. This certainly holds true for all versions of winderz up to and including XP. Re the FTDI serial <> USB adapters. We use them here for all sorts of comm's and hardware control stuff. Never had an issue with them. But we did have to go to FTDI's site and get the latest drivers, as the ones on the supplied CD were it seems known to be buggy. (At that time, the "Best" ones stability wise, were the "Unsigned" versions.) We even use the DTR/RTS lines for interface power, control and signaling! They work well, unlike some lesser products. There is at least one "popular" make, where some of the driver API call's do nothing but return with a good result code. In particular, the flush buffer call's! (It took us a long time to figure that one out!) So long as the caling program uses the documented Windows API call's for serial port stuff (messy though it is) you can have ports from COM1 to COM255 with 2000 & XP, and they work just fine. Else, use a third party driver suite, such as Marshallsoft's WSC collection. Fast, stable and well documented. It's worth the expenditure. They do versions for all the popular programming languages, VB, C, Delphi etc. One thing I have learnt to do with "new code" though, is watch it's memory usage in Task Mangler (er, Manager) to make sure there is no creaping excessive useage of ram as time goes by. Not sure is that is what's termed a "Memory Leak", but I've seen it sometimes with my own code, as well as other peoples. Even with good code, it often takes an hour or so for things to "settle" and become stable, as far as those figures in TM go. I've little experience of Vista, and none of Win7, yet. It'll be "interesting" to see if the XP Virtual Machine in Windows 7 Pro', also handles Win16 stuff OK. Im not holding my breath for that. Best Regards. Dave B. ------------------------------ Message: 7 Date: Mon, 16 Nov 2009 17:56:19 -0500 From: David Bengtson Subject: Re: [time-nuts] Lady Heather Serial receive Error 0x2 To: time-nuts at febo.com Message-ID: Content-Type: text/plain; charset=ISO-8859-1 Hi All I finally managed to get some time to figure this out. I was using a usb-serial interface with the FTDI chipset, and I had to tweak two parameters to get it working. First, I had to tell the driver that I didn't have a serial mouse (Serial enumnerator checkbox) and the second thing was to tweak the serial buffer. It was set to 4k, which was too large. I changed that to 1k, and it's been running for ~ 20 hours happily. Dave On Tue, Nov 3, 2009 at 9:53 PM, David Bengtson wrote: > Hi All: > > I'm running what I believe to be the latest version of Lady Heather on > a Windows XP laptop. I'm using a USB-Serial interface, and I'm getting > this error after about 15 to 20 minutes of data taking. I haven't seen > any recent discussion on this problem, I'm curious to know if anyone > else has seen this, and if they've figured it out. Once the error > message shows up, I quit out and restart the app, and it works fine. > I'm starting it with a shortcut ?"C:\Program > Files\Heather\heather.exe" /7 to point it at the com7 serial porty. > > Thanks > > > Dave > ------------------------------ Message: 8 Date: Mon, 16 Nov 2009 16:51:02 -0800 From: "John Miles" Subject: Re: [time-nuts] Lady Heather Serial receive Error 0x2 To: "Discussion of precise time and frequency measurement" Message-ID: Content-Type: text/plain; charset="iso-8859-1" The upcoming 3.0 version will have much better serial code (i.e., Mark's, rather than mine) but yes, it may still be vulnerable to the Windows serial-mouse lameness. I'm not sure why the FIFO buffer size should have mattered, though. If any other information on that comes to light, I'd be curious to hear about it. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of David Bengtson > Sent: Monday, November 16, 2009 2:56 PM > To: time-nuts at febo.com > Subject: Re: [time-nuts] Lady Heather Serial receive Error 0x2 > > > Hi All > > I finally managed to get some time to figure this out. I was using a > usb-serial interface with the FTDI chipset, and I had to tweak two > parameters to get it working. First, I had to tell the driver that I > didn't have a serial mouse (Serial enumnerator checkbox) and the > second thing was to tweak the serial buffer. It was set to 4k, which > was too large. I changed that to 1k, and it's been running for ~ 20 > hours happily. > > Dave > > On Tue, Nov 3, 2009 at 9:53 PM, David Bengtson > wrote: > > Hi All: > > > > I'm running what I believe to be the latest version of Lady Heather > > on a Windows XP laptop. I'm using a USB-Serial interface, and I'm > > getting this error after about 15 to 20 minutes of data taking. I > > haven't seen any recent discussion on this problem, I'm curious to > > know if anyone else has seen this, and if they've figured it out. > > Once the error message shows up, I quit out and restart the app, and it works fine. > > I'm starting it with a shortcut ?"C:\Program > > Files\Heather\heather.exe" /7 to point it at the com7 serial porty. > > > > Thanks > > > > > > Dave > > > From djl at montana.com Tue Nov 17 20:37:11 2009 From: djl at montana.com (Don Latham) Date: Tue, 17 Nov 2009 13:37:11 -0700 Subject: [time-nuts] Reference oscillator accuracy References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com><4AFDA63F.5040105@kasperkp.dk><94E812E8F29641488680719656A4E639@OFFICE2> <662624584-1258152708-cardhu_decombobulator_blackberry.rim.net-1937352721-@bda224.bisx.prod.on.blackberry> Message-ID: <4F33A40701514002947B3CEBC553E449@OFFICE2> Thanks, Didier. I've uploaded "diurnaltot.jpg". It is not fancy, but is readable. Anyone interested in on-or off-line csn email me. Seems as if the demise of loran will kill this, unless groundwave from wwvb at 60 khz is of interest. Don Latham ----- Original Message ----- From: "Didier Juges" To: "Time-Nuts" Sent: Friday, November 13, 2009 3:51 PM Subject: Re: [time-nuts] Reference oscillator accuracy > Don, you are welcome to upload your pictures (and paper) to my web site, > where people normally upload manuals. > > Didier KO4BB > > http://www.ko4bb.com/cgi-bin/manuals.pl > > > ------------------------ Sent from my BlackBerry Wireless thingy while I > do other things... > > -----Original Message----- > From: "Don Latham" > Date: Fri, 13 Nov 2009 15:01:47 > To: Discussion of precise time and frequency > measurement > Subject: Re: [time-nuts] Reference oscillator accuracy > > Hi All: I've copied my paper "Diurnal frequency variation and refractive > index" from Nature Physical Sciences, Vol. 234, 51, pp. 157-158, Dec. 20, > 1971. There are two TIFF files (I tried like heck to get them in one file, > and failed miserably, cannot understand my image software worth a #$%^. > The > way to calculate the refractive index of moist air is given. I don't know > how to post these images to the list, so help please. There was no reason > to > pursue the idea at the time, so maybe with the extensive network of the > time-nuts some sense can be made of the idea. Dunno. > Don Latham > > ----- Original Message ----- > From: "Kasper Pedersen" > To: > Sent: Friday, November 13, 2009 11:32 AM > Subject: Re: [time-nuts] Reference oscillator accuracy > > >> On 11/13/2009 07:15 PM, Don Latham wrote: >>> The ground wave path of WWVB varies due to a very small changes in the >>> index of refraction (temperature and absolute humidity) over the path. >>> It >>> is not much, but is measurable. >>> Don >>> >> >> My own nuttiness started with that, and the innocent question "How much? >> What does it take to measure it? What do I need to build?" >> >> http://n1.taur.dk/dcf/ (raw data and plots, time is UTC+1) >> >> I am no more than 6-700 km north of DCF77, and get ~5us p-p. Now that is >> quite large, when I started out that number seemed a lot smaller. >> >> /Kasper Pedersen >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From paulswedb at gmail.com Tue Nov 17 21:01:36 2009 From: paulswedb at gmail.com (paul swed) Date: Tue, 17 Nov 2009 16:01:36 -0500 Subject: [time-nuts] Reference oscillator accuracy In-Reply-To: <4F33A40701514002947B3CEBC553E449@OFFICE2> References: <6.2.3.4.2.20091113005958.05b56030@mail.bellsouth.net> <4AFD9BE3.8020007@gmail.com> <39fea4fba6b1278764817a7b8b7f0e14.squirrel@webmail.montana.com> <4AFDA63F.5040105@kasperkp.dk> <94E812E8F29641488680719656A4E639@OFFICE2> <662624584-1258152708-cardhu_decombobulator_blackberry.rim.net-1937352721-@bda224.bisx.prod.on.blackberry> <4F33A40701514002947B3CEBC553E449@OFFICE2> Message-ID: Well I have to say, I resurrected my gertch RLA1 wwvb rcvr. In New England wwvb will be difficult. I have had it running 2 weeks now and would guess its good to 1X10-11 sort of. Just to many things going on. Even though I have a resonated 60KC loop properly pointed at wwvb. So will guess gps it will be. I sure liked LORAN C and the austrons as a double check. Experimenting with tracor 599h to see if they work better and supposedly they can actually use the other vlf transmissions as a reference. I have naa in maine about 100-150 miles. Its very very strong but has msk keying. Again reading the 559 manual it doesn't care. Will fire it up tonight to see. Heavens knows what naas stability is they certainly do not need it. Regards On Tue, Nov 17, 2009 at 3:37 PM, Don Latham wrote: > Thanks, Didier. I've uploaded "diurnaltot.jpg". It is not fancy, but is > readable. > Anyone interested in on-or off-line csn email me. Seems as if the demise > of loran will kill this, unless groundwave from wwvb at 60 khz is of > interest. > > Don Latham > > > ----- Original Message ----- From: "Didier Juges" > To: "Time-Nuts" > Sent: Friday, November 13, 2009 3:51 PM > Subject: Re: [time-nuts] Reference oscillator accuracy > > > Don, you are welcome to upload your pictures (and paper) to my web site, >> where people normally upload manuals. >> >> Didier KO4BB >> >> http://www.ko4bb.com/cgi-bin/manuals.pl >> >> >> ------------------------ Sent from my BlackBerry Wireless thingy while I >> do other things... >> >> -----Original Message----- >> From: "Don Latham" >> Date: Fri, 13 Nov 2009 15:01:47 >> To: Discussion of precise time and frequency measurement< >> time-nuts at febo.com> >> Subject: Re: [time-nuts] Reference oscillator accuracy >> >> Hi All: I've copied my paper "Diurnal frequency variation and refractive >> index" from Nature Physical Sciences, Vol. 234, 51, pp. 157-158, Dec. 20, >> 1971. There are two TIFF files (I tried like heck to get them in one file, >> and failed miserably, cannot understand my image software worth a #$%^. >> The >> way to calculate the refractive index of moist air is given. I don't know >> how to post these images to the list, so help please. There was no reason >> to >> pursue the idea at the time, so maybe with the extensive network of the >> time-nuts some sense can be made of the idea. Dunno. >> Don Latham >> >> ----- Original Message ----- From: "Kasper Pedersen" < >> time-nuts at kasperkp.dk> >> To: >> Sent: Friday, November 13, 2009 11:32 AM >> Subject: Re: [time-nuts] Reference oscillator accuracy >> >> >> On 11/13/2009 07:15 PM, Don Latham wrote: >>> >>>> The ground wave path of WWVB varies due to a very small changes in the >>>> index of refraction (temperature and absolute humidity) over the path. >>>> It >>>> is not much, but is measurable. >>>> Don >>>> >>>> >>> My own nuttiness started with that, and the innocent question "How much? >>> What does it take to measure it? What do I need to build?" >>> >>> http://n1.taur.dk/dcf/ (raw data and plots, time is UTC+1) >>> >>> I am no more than 6-700 km north of DCF77, and get ~5us p-p. Now that is >>> quite large, when I started out that number seemed a lot smaller. >>> >>> /Kasper Pedersen >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From sar10538 at gmail.com Wed Nov 18 08:18:52 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Wed, 18 Nov 2009 21:18:52 +1300 Subject: [time-nuts] Rubidium standard In-Reply-To: <20091112125151.695AE1165C1@hamburg.alientech.net> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> Message-ID: <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> 2009/11/13 Mike S : > I'm sure someone with more statistics background can add to this, but useful > (or expected) lifetime cannot be determined from an MTBF number. > > Here's an example I found, demonstrating this: > > "There are 500,000 25-year-old humans in the sample population. > Over the course of a year, data is collected on failures (deaths) for this > population. > The operational life of the population is 500,000 x 1 year = 500,000 people > years. > Throughout the year, 625 people failed (died). > The failure rate is 625 failures / 500,000 people years = 0.125% / year. > The MTBF is the inverse of failure rate or 1 / 0.00125 = 800 years. > So, even though 25-year-old humans have high MTBF values, their life > expectancy > (service life) is much shorter and does not correlate." I don't know where you found this statement but I's check and change you get from them for wooden nickels. Humans have predefined lifetimes and such calculations for MTBF does not apply here. The failure rate of a human is not constant over the lifetime and just taking a figure at the age of 25 will get you nowhere. Try doing the same exercise at ages 70 or 80 and you can see how it does not work. This is another example of how statistics can be abused. Very amusing though, thanks for posting this. Steve -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. From david.partridge at dsl.pipex.com Wed Nov 18 09:42:40 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Wed, 18 Nov 2009 09:42:40 -0000 Subject: [time-nuts] Rubidium standard In-Reply-To: <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net><06F48D49E69D48D59499345A71F41403@devoffice><20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> Message-ID: >The failure rate of a human is not constant over the lifetime and just taking a figure at the age of 25 will get you nowhere. Steve, I think you'll find that's a total red herring. That's because if you measure failure rates of almost anything, you will find that the failure rate varies over their life time, increasing as they get older, often very dramatically in the final stages ... Now we can argue about "life-time" and such, but the point that Mike S was making that lifetime != inverse MTBF is still very true, and the example wasn't all that bad either. I can't think of many manufactured things that don't have a lifetime that is unrelated to MTBF figures early in their life. Dave From sar10538 at gmail.com Wed Nov 18 10:22:04 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Wed, 18 Nov 2009 23:22:04 +1300 Subject: [time-nuts] Rubidium standard In-Reply-To: References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> Message-ID: <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> Dave, The point I should have made is that most quoted MTBF figures have a reasonable bearing on the lifetime of the item, this example was well off given the inbuilt expiry dates of humans. In addition, a lot of us are using equipment that is well past it's use by date and it keeps on going, humans can't (at present) be repaired to last 600 years. I believe the lifetime of the machine is related to the usability of the item and you can't just assume that the item will just fail at 1 second past the MTBF. If the item fails early on, it can frequently be repaired and then continue to perform for the expected lifetime. Reports from other members of the group who have repaired rb units seem to support this. Manufactures can only give us some idea of how long their devices should be expected to last and the only real tool that gets anywhere near being practical is the MTBF. This enables us to plan the for the reasonable expected lifetimes of the systems we build and the maintenance swapouts/upgrade plans. If any manufacturer starts giving out very optimistic MTBFs then they will surely get a lot of negative feedback from their customers and probable loss of business due to loss of trust. I felt that an example based on humans was not really applicable to the real world of electronic items but that is my own opinion and I'm happy if you disagree with me. Cheers, Steve 2009/11/18 David C. Partridge : >>The failure rate of a human is not constant over the lifetime and just > taking a figure at the age of 25 will get you nowhere. > > Steve, ?I think you'll find that's a total red herring. > > That's because if you measure failure rates of almost anything, you will > find that the failure rate varies over their life time, increasing as they > get older, often very dramatically in the final stages ... > > Now we can argue about "life-time" and such, but the point that Mike S was > making that lifetime != inverse MTBF is still very true, and the example > wasn't all that bad either. ?I can't think of many manufactured things that > don't have a lifetime that is unrelated to MTBF figures early in their life. > > Dave > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. From mikes at flatsurface.com Wed Nov 18 12:54:48 2009 From: mikes at flatsurface.com (Mike S) Date: Wed, 18 Nov 2009 07:54:48 -0500 Subject: [time-nuts] Rubidium standard In-Reply-To: <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.co m> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> Message-ID: <20091118131845.A00C01165C1@hamburg.alientech.net> At 05:22 AM 11/18/2009, Steve Rooke wrote... >The point I should have made is that most quoted MTBF figures have a >reasonable bearing on the lifetime of the item, But your point would then be almost perfectly incorrect. MTBFs are not meant to, nor do they, predict product lifetimes. They are measures/predictions of product reliability. "What does MTBF have to do with lifetime? Nothing at all!" - http://www.ece.cmu.edu/~ganger/ece546.spring02/readings/mtbf.description "MTBF represents the statistical approximation of how long a number of units should operate before a failure can be expected. It is expressed in hours and does not represent how long the unit will last." - Learn (or review) the difference between MTBF and lifetime, Control Engineering, 9/24/2008; http://www.controleng.com/article/312365-Learn_or_review_the_difference_between_MTBF_and_lifetime.php I don't grant Wikipedia strong authority, but it is useful, and has this to say: "MTBF is commonly confused with a component's useful life, even though the two concepts are not related in any way. For example a battery may have a useful life of four hours, and an MTBF of 100,000 hours. These figures indicate that in a population of 100,000 batteries, there will be approximately one battery failure every hour during a single battery's four-hour life span." There's much more out there, if you make the effort. >I felt that an example based on humans was not really applicable to >the real world of electronic items but that is my own opinion and I'm >happy if you disagree with me. MTBFs are not exclusive to electronics. Statistics, math and MTBFs are objective matters, so your opinion really doesn't make any difference. From jherrero at hvsistemas.es Wed Nov 18 13:39:52 2009 From: jherrero at hvsistemas.es (Javier Herrero) Date: Wed, 18 Nov 2009 14:39:52 +0100 Subject: [time-nuts] Rubidium standard In-Reply-To: <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> Message-ID: <4B03F928.4010607@hvsistemas.es> Steve Rooke escribi?: >> The MTBF is the inverse of failure rate or 1 / 0.00125 = 800 years. The meaning is that if you a representative sample of 25 year-old humans, and their ages remains at 25 years constantly during 800 years, you should expect that half of the humans would have failed ater 800 years ;) Also in this case would be better to use Mean Time To Fail instead of Mean Time Between Failures. The problem is that we usually are only at 25 year age during a year (less if we have a 'failure') Regards, Javier -- ------------------------------------------------------------------------ Javier Herrero EMAIL: jherrero at hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17A FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com From alan.melia at btinternet.com Wed Nov 18 14:27:18 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Wed, 18 Nov 2009 14:27:18 -0000 Subject: [time-nuts] Rubidium standard References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net><06F48D49E69D48D59499345A71F41403@devoffice><20091112125151.695AE1165C1@hamburg.alientech.net><1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com><1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> Message-ID: <001b01ca685c$8e1ebee0$0900a8c0@lark> The big problem with MTBF is that it doesnt really mean ANYTHING if you invoke the proper statistical properties of the calculation! It is a process dreamed up out of thin air by Military and other users who felt they needed an index of quality and at least some "life testing" on the product they were buying without elevating the price too much, as proper life tests would. Mathematically it is highly suspect, but that depends on how the figures are used and most involved....management level :-)) dont understand Statistics....... so they are invariably mis-used ! Alan G3NYK ----- Original Message ----- From: "Mike S" To: "Discussion of precise time and frequency measurement" Sent: Wednesday, November 18, 2009 12:54 PM Subject: Re: [time-nuts] Rubidium standard > At 05:22 AM 11/18/2009, Steve Rooke wrote... > >The point I should have made is that most quoted MTBF figures have a > >reasonable bearing on the lifetime of the item, > > But your point would then be almost perfectly incorrect. MTBFs are not > meant to, nor do they, predict product lifetimes. They are > measures/predictions of product reliability. > > "What does MTBF have to do with lifetime? Nothing at all!" - > http://www.ece.cmu.edu/~ganger/ece546.spring02/readings/mtbf.description > > "MTBF represents the statistical approximation of how long a number of > units should operate before a failure can be expected. It is expressed > in hours and does not represent how long the unit will last." - Learn > (or review) the difference between MTBF and lifetime, Control > Engineering, 9/24/2008; > http://www.controleng.com/article/312365-Learn_or_review_the_difference_betw een_MTBF_and_lifetime.php > > I don't grant Wikipedia strong authority, but it is useful, and has > this to say: "MTBF is commonly confused with a component's useful life, > even though the two concepts are not related in any way. For example a > battery may have a useful life of four hours, and an MTBF of 100,000 > hours. These figures indicate that in a population of 100,000 > batteries, there will be approximately one battery failure every hour > during a single battery's four-hour life span." > > There's much more out there, if you make the effort. > > >I felt that an example based on humans was not really applicable to > >the real world of electronic items but that is my own opinion and I'm > >happy if you disagree with me. > > MTBFs are not exclusive to electronics. Statistics, math and MTBFs are > objective matters, so your opinion really doesn't make any difference. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From david.partridge at dsl.pipex.com Wed Nov 18 14:47:33 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Wed, 18 Nov 2009 14:47:33 -0000 Subject: [time-nuts] Rubidium standard In-Reply-To: <001b01ca685c$8e1ebee0$0900a8c0@lark> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net><06F48D49E69D48D59499345A71F41403@devoffice><20091112125151.695AE1165C1@hamburg.alientech.net><1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com><1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com><20091118131845.A00C01165C1@hamburg.alientech.net> <001b01ca685c$8e1ebee0$0900a8c0@lark> Message-ID: <14A442D7A0C3459FBDF1888D013B5E6F@APOLLO> If it weren't so horribly true I would be ROTFLMAO! Dave -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Alan Melia Sent: 18 November 2009 14:27 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Rubidium standard The big problem with MTBF is that it doesnt really mean ANYTHING if you invoke the proper statistical properties of the calculation! It is a process dreamed up out of thin air by Military and other users who felt they needed an index of quality and at least some "life testing" on the product they were buying without elevating the price too much, as proper life tests would. Mathematically it is highly suspect, but that depends on how the figures are used and most involved....management level :-)) dont understand Statistics....... so they are invariably mis-used ! Alan G3NYK From tholmes at woh.rr.com Wed Nov 18 15:05:03 2009 From: tholmes at woh.rr.com (Tom Holmes, N8ZM) Date: Wed, 18 Nov 2009 10:05:03 -0500 Subject: [time-nuts] Rubidium standard In-Reply-To: <001b01ca685c$8e1ebee0$0900a8c0@lark> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net><06F48D49E69D48D59499345A71F41403@devoffice><20091112125151.695AE1165C1@hamburg.alientech.net><1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com><1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> <001b01ca685c$8e1ebee0$0900a8c0@lark> Message-ID: <009f01ca6860$820bf010$8623d030$@rr.com> From phk at phk.freebsd.dk Wed Nov 18 15:14:08 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 18 Nov 2009 15:14:08 +0000 Subject: [time-nuts] Rubidium standard In-Reply-To: Your message of "Wed, 18 Nov 2009 10:05:03 EST." <009f01ca6860$820bf010$8623d030$@rr.com> Message-ID: <20035.1258557248@critter.freebsd.dk> It used to be, that if you knew the right people at IBM, you could get a printout of the actually in-field observed MTBF of all their components. That database is why they managed to respond to the infamous "legionnaires disease" in one of their DASD units, where pretty much all shipped drives died within a very narrow range of power-on hours, without running into any major lawsuits for incompetence. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From EWKehren at aol.com Wed Nov 18 16:22:27 2009 From: EWKehren at aol.com (EWKehren at aol.com) Date: Wed, 18 Nov 2009 11:22:27 EST Subject: [time-nuts] Vectron Osc. Message-ID: I have two Vectron Labratories CO-255A17-R 400 MHz Crystal Oscillators that I would like to use but have no information on. They are 2X3 inches 3/4 high SMA output and have five pins on the bottom, two are ground. Does any one have information. Thank you Bert Kehren Miami From jmfranke at cox.net Wed Nov 18 17:41:00 2009 From: jmfranke at cox.net (jmfranke) Date: Wed, 18 Nov 2009 12:41:00 -0500 Subject: [time-nuts] Vectron Osc. References: Message-ID: <622161A6C6854B85840C7A79B1DB8D74@Franke> For the CO-255 Series: Holding the oscillator with the SMA connector up and looking at the bottom, reading left to righ; 1. Supply (+) 2. Case 3. N/C (No connection) gap 4. 0V, Case and below: 5. Case. By the way, the A17 series has a stability rating for =15C t0 +35C of +/- 1 part in 10,000,000. Standard voltage is +15V @ <50mA for option R and output is >1.0Vrms/50 Ohms (+13 dBm) I can send the data sheet if needed. John WA4WDL -------------------------------------------------- From: Sent: Wednesday, November 18, 2009 11:22 AM To: Subject: [time-nuts] Vectron Osc. > I have two Vectron Labratories CO-255A17-R 400 MHz Crystal Oscillators > that > I would like to use but have no information on. They are 2X3 inches 3/4 > high SMA output and have five pins on the bottom, two are ground. Does > any > one have information. Thank you > Bert Kehren Miami > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From msokolov at ivan.Harhan.ORG Wed Nov 18 18:14:46 2009 From: msokolov at ivan.Harhan.ORG (Michael Sokolov) Date: Wed, 18 Nov 2009 18:14:46 GMT Subject: [time-nuts] MTBF (was Rubidium standard) Message-ID: <0911181814.AA27091@ivan.Harhan.ORG> As I have learned in school from a department head, mean time between failures (MTBF) means anything only if you are being mean. If you are not being mean, it means nothing. MS From mikes at flatsurface.com Wed Nov 18 19:06:55 2009 From: mikes at flatsurface.com (Mike S) Date: Wed, 18 Nov 2009 14:06:55 -0500 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: <0911181814.AA27091@ivan.Harhan.ORG> References: <0911181814.AA27091@ivan.Harhan.ORG> Message-ID: <20091118190740.2BABA53827@hamburg.alientech.net> At 01:14 PM 11/18/2009, Michael Sokolov wrote... >As I have learned in school from a department head, mean time between >failures (MTBF) means anything only if you are being mean. If you are >not being mean, it means nothing. There is at least one practical use for MTBF, at least the real-world statistical form. If one has a reasonably large population of devices to maintain, the number of spare devices needed to stay operational is a function of the MTBF. If you've got 10,000 cell sites, each with an Rb timebase, MTBF figures can provide a pretty accurate estimate of how often one will fail and need to be replaced, at least during the normal lifetime (between the infant mortality and wearout stages). Coupled with MTTR statistics, one can figure out how many spares should be stocked. Manufacturers invest a lot of effort into using such statistical measures to determine how many spare parts should be kept at various points in the supply chain. Unnecessary parts on shelves = wasted capital. Manufacturers also use MTBF statistics to price service contracts on equipment. This only works when one is dealing with a large population of devices, so MTBF is meaningless at the individual unit level. From kyrrin at bluefeathertech.com Wed Nov 18 19:09:08 2009 From: kyrrin at bluefeathertech.com (Bruce Lane) Date: Wed, 18 Nov 2009 11:09:08 -0800 Subject: [time-nuts] Kode-Odetics Model 285 Message-ID: <200911181109080812.009407A1@192.168.42.129> Fellow temporal twisters, I've just become the proud owner of a Kode-Odetics model 285 TCG/Translator unit, in beautiful condition. I've already archived its PROMs, but I'm wondering if anyone has the tech manual for this beastie...? Thanks much. Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies (http://www.bluefeathertech.com) Assoc. member, IMATA, AZA & AAZK for many moons. "Salvadore Dali's computer has surreal ports..." From wpxs472 at gmail.com Wed Nov 18 19:48:06 2009 From: wpxs472 at gmail.com (John Green) Date: Wed, 18 Nov 2009 13:48:06 -0600 Subject: [time-nuts] MTBF/MTTF etc. Message-ID: The discussion on the merits of failure rate calculations is fascinating. I was asked by one of our customers to provide MTBF for our products. After some research, I told them I couldn't provide that data and didn't think it would be of much use if I did. I asked if MTTF wouldn't be a better figure and they said "no" but gave no reason why. They asked about failures reported by our customers over the years. I replied that in 15 or so years of making that product, we have not received a single report of failure in the field. In that time, we have made probably 50 million at least, so our MTBF should be pretty good. The one thing all that ignores is that our product (molded thick film attenuators) if discovered defective in the field is just tossed by a technician and a new one installed. They are pretty reliable though. I just can't say with certainty how reliable. From alan.melia at btinternet.com Wed Nov 18 21:21:11 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Wed, 18 Nov 2009 21:21:11 -0000 Subject: [time-nuts] MTBF (was Rubidium standard) References: <0911181814.AA27091@ivan.Harhan.ORG> <20091118190740.2BABA53827@hamburg.alientech.net> Message-ID: <007501ca689f$d711fed0$0900a8c0@lark> Sorry Mike , unless, as someone else said, the figures are derived from field failures over at least a good porton of the expected like the MTBF tells you absolutely nothing!! The statistics used on the usual 1000hour test will only tell you the probability of failure in the first 1000hours of use!! It cannot tell you anything mathematically about the extrapolated life....this has become another urban myth. If it works it is more by luck that by mathematical probability. Alan G3NYK ----- Original Message ----- From: "Mike S" To: "Discussion of precise time and frequency measurement" Sent: Wednesday, November 18, 2009 7:06 PM Subject: Re: [time-nuts] MTBF (was Rubidium standard) > At 01:14 PM 11/18/2009, Michael Sokolov wrote... > >As I have learned in school from a department head, mean time between > >failures (MTBF) means anything only if you are being mean. If you are > >not being mean, it means nothing. > > There is at least one practical use for MTBF, at least the real-world > statistical form. > > If one has a reasonably large population of devices to maintain, the > number of spare devices needed to stay operational is a function of the > MTBF. > > If you've got 10,000 cell sites, each with an Rb timebase, MTBF figures > can provide a pretty accurate estimate of how often one will fail and > need to be replaced, at least during the normal lifetime (between the > infant mortality and wearout stages). Coupled with MTTR statistics, one > can figure out how many spares should be stocked. > > Manufacturers invest a lot of effort into using such statistical > measures to determine how many spare parts should be kept at various > points in the supply chain. Unnecessary parts on shelves = wasted > capital. Manufacturers also use MTBF statistics to price service > contracts on equipment. > > This only works when one is dealing with a large population of devices, > so MTBF is meaningless at the individual unit level. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From SAIDJACK at aol.com Wed Nov 18 23:01:06 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Wed, 18 Nov 2009 18:01:06 EST Subject: [time-nuts] MTBF (was Rubidium standard) Message-ID: Hi Alan, I am reading a book about the Apollo computer, they bet their life on it not failing (everything related to spacecraft maneuvering went through the computer, there were no mechanical or other backups whatsoever). They only had a single computer per spacecraft! The book states that based on the entire Apollo program, they later estimated the units MTBF to be in excess of 50,000 hours (which is actually not a lot compared to what typical GPSDO's can achieve today). A single transistor, ROM bit, solder-joint, or resistor failure could have killed them. Scary considering they went for 2 week+ missions.. bye, Said In a message dated 11/18/2009 14:38:57 Pacific Standard Time, alan.melia at btinternet.com writes: Sorry Mike , unless, as someone else said, the figures are derived from field failures over at least a good porton of the expected like the MTBF tells you absolutely nothing!! The statistics used on the usual 1000hour test will only tell you the probability of failure in the first 1000hours of use!! It cannot tell you anything mathematically about the extrapolated life....this has become another urban myth. If it works it is more by luck that by mathematical probability. Alan G3NYK From phk at phk.freebsd.dk Wed Nov 18 23:06:38 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 18 Nov 2009 23:06:38 +0000 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: Your message of "Wed, 18 Nov 2009 18:01:06 EST." Message-ID: <68702.1258585598@critter.freebsd.dk> In message , SAIDJACK at aol.com writes: >A single transistor, ROM bit, solder-joint, or resistor failure could have >killed them. Actually there were a perfectly good spare in the lunar lander module and most single points of failure would not kill them, but merely cause the mission to abort and head home. They also hard backup navigational aids. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From mikes at flatsurface.com Wed Nov 18 23:10:55 2009 From: mikes at flatsurface.com (Mike S) Date: Wed, 18 Nov 2009 18:10:55 -0500 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: <007501ca689f$d711fed0$0900a8c0@lark> References: <0911181814.AA27091@ivan.Harhan.ORG> <20091118190740.2BABA53827@hamburg.alientech.net> <007501ca689f$d711fed0$0900a8c0@lark> Message-ID: <20091118231136.07A3953827@hamburg.alientech.net> At 04:21 PM 11/18/2009, Alan Melia wrote... >Sorry Mike , unless, as someone else said, the figures are derived >from >field failures over at least a good porton of the expected like the >MTBF >tells you absolutely nothing!! That is exactly what I meant by "the real-world statistical form" - data gathered from in-service operation, not lab tests (or worse, a purely mathematical combination of individual component MTBFs, like one resistor contributes X, an IC of a certain type contributes Y, etc.). But, things have to start from somewhere (e.g. a need to deploy spares for a new product) so manufacturers will use shortcuts (lab testing, etc.) for initial numbers, then refine based on experience. That doesn't mean the shortcut methods are useless, only that they're less accurate. Something is better than "nothing," and a simple device can be expected to have a higher MTBF than a complex one (assuming similar technologies, manufacturing processes, etc.). So I don't agree with your "absolutely nothing" statement. Having an HP5071 doesn't make a Timex worthless. From rdarlington at gmail.com Wed Nov 18 23:17:19 2009 From: rdarlington at gmail.com (Robert Darlington) Date: Wed, 18 Nov 2009 16:17:19 -0700 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: References: Message-ID: Aside from the spare in the LM, they had a backup computer called the abort guidance system developed by TRW. I think it was bolted up under a seat somewhere. -Bob On Wed, Nov 18, 2009 at 4:01 PM, wrote: > Hi Alan, > > I am reading a book about the Apollo computer, they bet their life on it > not failing (everything related to spacecraft maneuvering went through the > computer, there were no mechanical or other backups whatsoever). They only > had a single computer per spacecraft! > > The book states that based on the entire Apollo program, they later > estimated the units MTBF to be in excess of 50,000 hours (which is actually > not a > lot compared to what typical GPSDO's can achieve today). > > A single transistor, ROM bit, solder-joint, or resistor failure could have > killed them. > > Scary considering they went for 2 week+ missions.. > > bye, > Said > > > > > In a message dated 11/18/2009 14:38:57 Pacific Standard Time, > alan.melia at btinternet.com writes: > > Sorry Mike , unless, as someone else said, the figures are derived from > field failures over at least a good porton of the expected like the MTBF > tells you absolutely nothing!! The statistics used on the usual 1000hour > test will only tell you the probability of failure in the first 1000hours > of > use!! It cannot tell you anything mathematically about the extrapolated > life....this has become another urban myth. If it works it is more by luck > that by mathematical probability. > > Alan G3NYK > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From SAIDJACK at aol.com Wed Nov 18 23:21:00 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Wed, 18 Nov 2009 18:21:00 EST Subject: [time-nuts] MTBF (was Rubidium standard) Message-ID: Hi Poul-Henning, from what I read, they a) had no tools to replace the units or even open the computer, b) the software was different between the units (LEM had 1/2 the ROM to save weight), and c) the spacecraft attitude thrusters and the main engines were fully computer controlled (their control Joysticks were true fly-by-wire, they went through the computer, and thruster control was done by software). So no computer meant no attitude thrusters or acceleration. So having to rely on two of these computers during the separated period would actually double their chances of some form of mission failure. Of course the LEM could not be used for re-entry in to the atmosphere either. If the Command Module computer failed (and it was apparently not built with redundant circuitry) then: - game over. But on the other hand they considered the human element failure, they had fully automatic return and landing capability in case the humans expired... bye, Said In a message dated 11/18/2009 15:07:02 Pacific Standard Time, phk at phk.freebsd.dk writes: In message , SAIDJACK at aol.com writes: >A single transistor, ROM bit, solder-joint, or resistor failure could have >killed them. Actually there were a perfectly good spare in the lunar lander module and most single points of failure would not kill them, but merely cause the mission to abort and head home. They also hard backup navigational aids. From SAIDJACK at aol.com Wed Nov 18 23:24:55 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Wed, 18 Nov 2009 18:24:55 EST Subject: [time-nuts] MTBF (was Rubidium standard) Message-ID: Hi Bob, I read this was done only on Block-1 systems. In Block-2 (the units that actually carried humans) they had all attitude thrusters, and the main engine control done by the computer itself. No spares or backup control systems for the thrusters! No CM computer, no return to earth. I think this is also discussed in the movie Apollo 13. bye, Said In a message dated 11/18/2009 15:17:59 Pacific Standard Time, rdarlington at gmail.com writes: Aside from the spare in the LM, they had a backup computer called the abort guidance system developed by TRW. I think it was bolted up under a seat somewhere. -Bob From phill.r1 at btinternet.com Wed Nov 18 23:25:23 2009 From: phill.r1 at btinternet.com (Roy Phillips) Date: Wed, 18 Nov 2009 23:25:23 -0000 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: References: Message-ID: <6B335CFA0A3B496B8180D851C1161559@LapTop> Hello Said What is the title / details of the book that you refer too ? Thanks Roy ----- Original Message ----- From: To: Sent: Wednesday, November 18, 2009 11:01 PM Subject: Re: [time-nuts] MTBF (was Rubidium standard) > Hi Alan, > > I am reading a book about the Apollo computer, they bet their life on it > not failing (everything related to spacecraft maneuvering went through the > computer, there were no mechanical or other backups whatsoever). They only > had a single computer per spacecraft! > > The book states that based on the entire Apollo program, they later > estimated the units MTBF to be in excess of 50,000 hours (which is > actually not a > lot compared to what typical GPSDO's can achieve today). > > A single transistor, ROM bit, solder-joint, or resistor failure could have > killed them. > > Scary considering they went for 2 week+ missions.. > > bye, > Said > > > > > In a message dated 11/18/2009 14:38:57 Pacific Standard Time, > alan.melia at btinternet.com writes: > > Sorry Mike , unless, as someone else said, the figures are derived from > field failures over at least a good porton of the expected like the MTBF > tells you absolutely nothing!! The statistics used on the usual 1000hour > test will only tell you the probability of failure in the first 1000hours > of > use!! It cannot tell you anything mathematically about the extrapolated > life....this has become another urban myth. If it works it is more by > luck > that by mathematical probability. > > Alan G3NYK > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From phk at phk.freebsd.dk Wed Nov 18 23:30:09 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Wed, 18 Nov 2009 23:30:09 +0000 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: Your message of "Wed, 18 Nov 2009 18:24:55 EST." Message-ID: <68766.1258587009@critter.freebsd.dk> In message , SAIDJACK at aol.com writes: >No CM computer, no return to earth. I think this is also discussed in the >movie Apollo 13. http://history.nasa.gov/ says otherwise. Lot of good stuff there. In particular: http://history.nasa.gov/computers/Part1.html -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From SAIDJACK at aol.com Wed Nov 18 23:39:54 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Wed, 18 Nov 2009 18:39:54 EST Subject: [time-nuts] MTBF (was Rubidium standard) Message-ID: Hi Roy, two of them: "Digital Apollo", Mindell, David A., MIT 2008 and: "Journey to the Moon, History of the Apollo Guidance Computer", Hall, Eldon C., 1996 The Mindell book is really excellent, reads like a novel, no EE degree required. Mindell discusses the trade-offs they made such as in-flight repair capability or not as well as the overall mission in great detail. The Hall book is written by an engineer that actually worked on the AGC, and very detailed, it includes schematics, many photos, GANTT charts, etc. This book is not as cohesive as the first one though, and focuses mostly on the computer rather than the mission. bye, Said In a message dated 11/18/2009 15:27:01 Pacific Standard Time, phill.r1 at btinternet.com writes: Hello Said What is the title / details of the book that you refer too ? Thanks Roy From SAIDJACK at aol.com Thu Nov 19 00:03:44 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Wed, 18 Nov 2009 19:03:44 EST Subject: [time-nuts] MTBF (was Rubidium standard) Message-ID: Hi Poul, that AGS system existed only on the LEM, and only to abort a lunar landing. It couldn't even dock the two craft. Mindell discusses in great detail how they went to a single-computer digital Autopilot on pages 138 to 143, because they considered a failure so remote as to being able to do away with redundant computers, or in-flight repair. Since all CM thrusters are controlled by the CM computer software, a landing would not be possible without it. See also figure 6.2 on page 142. But I think there was a manual way to start/stop the main engines, so maybe this would have been useful if the main computer failed to at least get back into an earth orbit? This was apparently the very first fully-digital 100% fly-by-wire system ever, and probably the last one that did not have redundant computer backup. bye, Said In a message dated 11/18/2009 15:30:36 Pacific Standard Time, phk at phk.freebsd.dk writes: In message , SAIDJACK at aol.com writes: >No CM computer, no return to earth. I think this is also discussed in the >movie Apollo 13. http://history.nasa.gov/ says otherwise. Lot of good stuff there. In particular: http://history.nasa.gov/computers/Part1.html From james.p.lux at jpl.nasa.gov Thu Nov 19 01:49:48 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Wed, 18 Nov 2009 17:49:48 -0800 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: Message-ID: Yeah, but in the one-off spaceflight world, MTBF calculations don't get used much, except perhaps to compare designs. (e.g. A design with an MTBF of 200khrs is probably better than one with 2000 hrs) The problem is that it's a statistical sort of life measure: out of 1000 units with an MTBF of 1000 hours, you can expect 500 to still be working at 1000 hours. It doesn't say much about whether your ONE box will be working at 10 hours, which is typically what you're worried about. What they do is buy good parts, use really skilled people and consistent processes, check everything 20 times (and how many times did we look at each solder joint), test the bejeebers out of the box at many stages, put a couple thousand hours on to get past infant mortality issues, and hope for the best. This is a somewhat conservative approach, which is why Mars rovers with a requirement for 90 day life are still going some 6 years later. On 11/18/09 3:01 PM, "SAIDJACK at aol.com" wrote: > Hi Alan, > > I am reading a book about the Apollo computer, they bet their life on it > not failing (everything related to spacecraft maneuvering went through the > computer, there were no mechanical or other backups whatsoever). They only > had a single computer per spacecraft! > > The book states that based on the entire Apollo program, they later > estimated the units MTBF to be in excess of 50,000 hours (which is actually > not a > lot compared to what typical GPSDO's can achieve today). > > A single transistor, ROM bit, solder-joint, or resistor failure could have > killed them. > > Scary considering they went for 2 week+ missions.. > > bye, > Said > > > > > In a message dated 11/18/2009 14:38:57 Pacific Standard Time, > alan.melia at btinternet.com writes: > > Sorry Mike , unless, as someone else said, the figures are derived from > field failures over at least a good porton of the expected like the MTBF > tells you absolutely nothing!! The statistics used on the usual 1000hour > test will only tell you the probability of failure in the first 1000hours > of > use!! It cannot tell you anything mathematically about the extrapolated > life....this has become another urban myth. If it works it is more by luck > that by mathematical probability. > > Alan G3NYK > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From tammy-lists at wiztech.biz Thu Nov 19 06:18:28 2009 From: tammy-lists at wiztech.biz (Tammy A. Wisdom) Date: Wed, 18 Nov 2009 23:18:28 -0700 (MST) Subject: [time-nuts] wtb: hp 5335a parts Message-ID: <1477723434.281258611508912.JavaMail.root@lordsofacid.wiztech.biz> Hi All, If you have a parts HP 5335A I am looking for option 010 (high stability osc) & option 030 (C channel input) Please let me know if you might have any of the parts I am looking for. contact me off list: tamara.wisdom_ at _wiztech.biz (remove _'s) Thanks --Tammy ****************************************************************************** Disclaimer: This e-mail may contain trade secrets or privileged, undisclosed or otherwise confidential information. If you have received this e-mail in error, you are hereby notified that any review, copying or distribution of it is strictly prohibited. Please inform us immediately and destroy the original transmittal. Thank you for your cooperation. ****************************************************************************** From hmurray at megapathdsl.net Thu Nov 19 09:06:46 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Thu, 19 Nov 2009 01:06:46 -0800 Subject: [time-nuts] MTBF (was Rubidium standard) In-Reply-To: Message from "Lux, Jim (337C)" of "Wed, 18 Nov 2009 17:49:48 PST." Message-ID: <20091119090647.A1DB8BCFC@ip-64-139-1-69.sjc.megapath.net> james.p.lux at jpl.nasa.gov said: > What they do is buy good parts, use really skilled people and > consistent processes, check everything 20 times (and how many times > did we look at each solder joint), test the bejeebers out of the box > at many stages, put a couple thousand hours on to get past infant > mortality issues, and hope for the best. I think you missed a critical step. When something breaks, a group of very smart people carefully analyze the event in case they can find an interesting pattern. How many other important steps have I overlooked? > This is a somewhat conservative approach, which is why Mars rovers > with a requirement for 90 day life are still going some 6 years later. Go rovers! http://bobpark.physics.umd.edu/WN08/wn032808.html It's really neat to have a successful project like that happen occasionally. -- These are my opinions, not necessarily my employer's. I hate spam. From sar10538 at gmail.com Thu Nov 19 09:09:44 2009 From: sar10538 at gmail.com (Steve Rooke) Date: Thu, 19 Nov 2009 22:09:44 +1300 Subject: [time-nuts] Rubidium standard In-Reply-To: <20091118131845.A00C01165C1@hamburg.alientech.net> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> Message-ID: <1231b6a80911190109n415ed618h3542b180f20a5b2a@mail.gmail.com> 2009/11/19 Mike S : > At 05:22 AM 11/18/2009, Steve Rooke wrote... >> >> The point I should have made is that most quoted MTBF figures have a >> reasonable bearing on the lifetime of the item, > > But your point would then be almost perfectly incorrect. MTBFs are not meant > to, nor do they, predict product lifetimes. They are measures/predictions of > product reliability. OK, I agree, the term is mean time between failures but the question is what is the lifetime of something. This is the point we are discussing and we really need to understand what this means. I'm not going to quote a number of web searches, this means different things to different people but this matter is not quite as black and while as you think. The lifetimes of any thing can be broadly split into two groups, there are things that have a predetermined lifespan, like lifeforms, and those that have no fixed lifespan. Let's look at the second broad category, as this is what we are really talking about. So what is the lifetime of an item in this category, is it related to MTBF or not. Well, lets see, take some items, like consumer goods, these are frequently thrown away when they fail as it is generally expensive to fix them and newer models are more attractive. Now, do all consumers wait till an item fails before they throw it away, well no, it depends on the culture but I bet a large proportion of consumers probably do wait till it fails. So in this case, quite a large section of what we are talking about, the lifetime of the item is related to the time it fails. Infant failures are obviously covered by initial warranty but this seems to indicate that for a large sample size, the products lifetime would be related to the MTBF. Agreed there are some assumptions there, I expect the MTBF of a cellphone is a reasonable amount but if you live in California and are seen with one over 6 months old you would die of embarrassment. So the lifespan of a cellphone in California is significanly shorter than the MTBF, the factor here is the MTBE (mean time before embarrassment). No lets look at the corporate environment. In this environment, failure of equipment can be very costly to a company so, if they have any sense, they will arange to upgrade equipment well inside the time that the item is expected to fail. Now, you may say that companies do this well inside a shorter cycle than this as they can amortise the cost off on tax release over a few years but I've worked in this industry long enough to know that budgets don't work that way in the real world and items get replaced when they fail. Again, with a large sample size, this equates the lifetime of an item with the MTBF. Now, there are those industries that do upgrade their things before they fail and including those things that have actually failed and been replaced, these things become available to people like us. Now, for us, the MTBF is not the relevant factor here as we will repair the thing, over and over again so it has a lifetime far in excess of it's MTBF. So, for the majority of cases in consumer an corporate usage, the lifespan of any thing is related to the MTBF. For the smart set with enough dosh, the lifespan of any thing is shorter than the MTBF, and for the poor buggers like, at least, some of us, the lifespan is greater then the MTBF. The point being that for the majority of cases, the lifespan of any item is related to it's MTBF for equivalent sample size. Now, I know that MTBF is related to the failure rate but failures determine the lifespan of any thing in the majority of cases. The guys that put people into space have to really understand that well. It's no good putting people into space for a 2 week mission in equipment that has an expected MTBF of 1 week unless you wish the mission to be only half completed given a sufficient sample size. It also causes a lot of paper work and hot air to be blown which is generally undesireable. > "What does MTBF have to do with lifetime? ?Nothing at all!" - > http://www.ece.cmu.edu/~ganger/ece546.spring02/readings/mtbf.description > > "MTBF represents the statistical approximation of how long a number of units > should operate before a failure can be expected. It is expressed in hours > and does not represent how long the unit will last." - Learn (or review) the > difference between MTBF and lifetime, Control Engineering, 9/24/2008; > http://www.controleng.com/article/312365-Learn_or_review_the_difference_between_MTBF_and_lifetime.php But all this means on whether you consider the lifespan of any item to be greater than the MTBF, IE. you don't mind the possibility of having to fix it a few times, or if you throw it out as soon as it fails, IE lifespan is related to MTBF. This, of course, does not cover instances for when there is a planned obsolescence of the item, then the lifespan is shorter than the MTBF but the swap out cycle has probably been planned from the MTBF in the first place. > I don't grant Wikipedia strong authority, but it is useful, and has this to > say: "MTBF is commonly confused with a component's useful life, even though > the two concepts are not related in any way. For example a battery may have > a useful life of four hours, and an MTBF of 100,000 hours. These figures > indicate that in a population of 100,000 batteries, there will be > approximately one battery failure every hour during a single battery's > four-hour life span." This is an example of an item with a specific lifespan and therefore MTBF is not related to a single items lifespan. In this case it determines the probability of failure of any item. Comparing the lifespan of items having a specific lifespan with their MTBF is like comparing apples with oranges. This is a bad example of what we were talking about. I agree that rb lamps do have a limited life but they can be replaced as they are just a component that fails in the actual whole item and this is just one failure in the terms of MTBF. > There's much more out there, if you make the effort. And there is much more in you if you logically think about it instead of just accepting things on the web without really thinking what we are relating to here. >> I felt that an example based on humans was not really applicable to >> the real world of electronic items but that is my own opinion and I'm >> happy if you disagree with me. > > MTBFs are not exclusive to electronics. Statistics, math and MTBFs are > objective matters, so your opinion really doesn't make any difference. Certainly statistics, math and MTBFs are objective and they have a specific bearing on this matter. Along with this, you need to add policy, as to how the entity using an item sees about its lifetime related to those objectives, IE. they are related. The lifetime of anything is a policy decision based on the items failure rate. Steve -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. From lists at cq.nu Thu Nov 19 12:56:27 2009 From: lists at cq.nu (Bob Camp) Date: Thu, 19 Nov 2009 07:56:27 -0500 Subject: [time-nuts] Rubidium standard / MTBF In-Reply-To: <1231b6a80911190109n415ed618h3542b180f20a5b2a@mail.gmail.com> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> <1231b6a80911190109n415ed618h3542b180f20a5b2a@mail.gmail.com> Message-ID: Hi Just to put some numbers on this stuff: A typical TV has a design goal of a > 5 year lifetime. A "premium" TV has a design goal of a > 10 year lifetime. The theory is that if it doesn't last that long, the customer will not buy another one from your brand. Here in the US, most cell phones get swapped at the end of the two year contract. It's a real good bet that they are designed to have a 2 year lifespan at around the 90 to 95% level. Again, same theory, if it dies we won't sell another one. I suspect the return rate also gets written into the contracts with the carriers. There are a whole lot of normal use assumptions in their calculations. You could debate the details for a *long* time. The one that I find the most shocking is the very major internet hardware company that considers 5 years of continuos use to be the goal. The logic - we want them to swap out the gear regularly.... Bottom line - your TV may be more reliable than your internet connection ... Crazy stuff Bob On Nov 19, 2009, at 4:09 AM, Steve Rooke wrote: > 2009/11/19 Mike S : >> At 05:22 AM 11/18/2009, Steve Rooke wrote... >>> >>> The point I should have made is that most quoted MTBF figures have a >>> reasonable bearing on the lifetime of the item, >> >> But your point would then be almost perfectly incorrect. MTBFs are not meant >> to, nor do they, predict product lifetimes. They are measures/predictions of >> product reliability. > > OK, I agree, the term is mean time between failures but the question > is what is the lifetime of something. This is the point we are > discussing and we really need to understand what this means. I'm not > going to quote a number of web searches, this means different things > to different people but this matter is not quite as black and while as > you think. > > The lifetimes of any thing can be broadly split into two groups, there > are things that have a predetermined lifespan, like lifeforms, and > those that have no fixed lifespan. Let's look at the second broad > category, as this is what we are really talking about. So what is the > lifetime of an item in this category, is it related to MTBF or not. > Well, lets see, take some items, like consumer goods, these are > frequently thrown away when they fail as it is generally expensive to > fix them and newer models are more attractive. Now, do all consumers > wait till an item fails before they throw it away, well no, it depends > on the culture but I bet a large proportion of consumers probably do > wait till it fails. So in this case, quite a large section of what we > are talking about, the lifetime of the item is related to the time it > fails. Infant failures are obviously covered by initial warranty but > this seems to indicate that for a large sample size, the products > lifetime would be related to the MTBF. Agreed there are some > assumptions there, I expect the MTBF of a cellphone is a reasonable > amount but if you live in California and are seen with one over 6 > months old you would die of embarrassment. So the lifespan of a > cellphone in California is significanly shorter than the MTBF, the > factor here is the MTBE (mean time before embarrassment). > > No lets look at the corporate environment. In this environment, > failure of equipment can be very costly to a company so, if they have > any sense, they will arange to upgrade equipment well inside the time > that the item is expected to fail. Now, you may say that companies do > this well inside a shorter cycle than this as they can amortise the > cost off on tax release over a few years but I've worked in this > industry long enough to know that budgets don't work that way in the > real world and items get replaced when they fail. Again, with a large > sample size, this equates the lifetime of an item with the MTBF. > > Now, there are those industries that do upgrade their things before > they fail and including those things that have actually failed and > been replaced, these things become available to people like us. Now, > for us, the MTBF is not the relevant factor here as we will repair the > thing, over and over again so it has a lifetime far in excess of it's > MTBF. > > So, for the majority of cases in consumer an corporate usage, the > lifespan of any thing is related to the MTBF. For the smart set with > enough dosh, the lifespan of any thing is shorter than the MTBF, and > for the poor buggers like, at least, some of us, the lifespan is > greater then the MTBF. The point being that for the majority of cases, > the lifespan of any item is related to it's MTBF for equivalent sample > size. > > Now, I know that MTBF is related to the failure rate but failures > determine the lifespan of any thing in the majority of cases. > > The guys that put people into space have to really understand that > well. It's no good putting people into space for a 2 week mission in > equipment that has an expected MTBF of 1 week unless you wish the > mission to be only half completed given a sufficient sample size. It > also causes a lot of paper work and hot air to be blown which is > generally undesireable. > >> "What does MTBF have to do with lifetime? Nothing at all!" - >> http://www.ece.cmu.edu/~ganger/ece546.spring02/readings/mtbf.description >> >> "MTBF represents the statistical approximation of how long a number of units >> should operate before a failure can be expected. It is expressed in hours >> and does not represent how long the unit will last." - Learn (or review) the >> difference between MTBF and lifetime, Control Engineering, 9/24/2008; >> http://www.controleng.com/article/312365-Learn_or_review_the_difference_between_MTBF_and_lifetime.php > > But all this means on whether you consider the lifespan of any item to > be greater than the MTBF, IE. you don't mind the possibility of having > to fix it a few times, or if you throw it out as soon as it fails, IE > lifespan is related to MTBF. This, of course, does not cover instances > for when there is a planned obsolescence of the item, then the > lifespan is shorter than the MTBF but the swap out cycle has probably > been planned from the MTBF in the first place. > >> I don't grant Wikipedia strong authority, but it is useful, and has this to >> say: "MTBF is commonly confused with a component's useful life, even though >> the two concepts are not related in any way. For example a battery may have >> a useful life of four hours, and an MTBF of 100,000 hours. These figures >> indicate that in a population of 100,000 batteries, there will be >> approximately one battery failure every hour during a single battery's >> four-hour life span." > > This is an example of an item with a specific lifespan and therefore > MTBF is not related to a single items lifespan. In this case it > determines the probability of failure of any item. Comparing the > lifespan of items having a specific lifespan with their MTBF is like > comparing apples with oranges. This is a bad example of what we were > talking about. I agree that rb lamps do have a limited life but they > can be replaced as they are just a component that fails in the actual > whole item and this is just one failure in the terms of MTBF. > >> There's much more out there, if you make the effort. > > And there is much more in you if you logically think about it instead > of just accepting things on the web without really thinking what we > are relating to here. > >>> I felt that an example based on humans was not really applicable to >>> the real world of electronic items but that is my own opinion and I'm >>> happy if you disagree with me. >> >> MTBFs are not exclusive to electronics. Statistics, math and MTBFs are >> objective matters, so your opinion really doesn't make any difference. > > Certainly statistics, math and MTBFs are objective and they have a > specific bearing on this matter. Along with this, you need to add > policy, as to how the entity using an item sees about its lifetime > related to those objectives, IE. they are related. The lifetime of > anything is a policy decision based on the items failure rate. > > Steve > -- > Steve Rooke - ZL3TUV & G8KVD > A man with one clock knows what time it is; > A man with two clocks is never quite sure. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From james.p.lux at jpl.nasa.gov Thu Nov 19 15:17:01 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Thu, 19 Nov 2009 07:17:01 -0800 Subject: [time-nuts] Rubidium standard / MTBF In-Reply-To: Message-ID: On 11/19/09 4:56 AM, "Bob Camp" wrote: > Hi > > The one that I find the most shocking is the very major internet hardware > company that considers 5 years of continuos use to be the goal. The logic - we > want them to swap out the gear regularly.... That's actually reasonable.. Moore's law is always advancing, performance is improving, and regular swaps avoid needing to support old versions for long times. A pretty simple financial analysis shows what the optimum plan would be, and I'm sure that's what the MIHC does. We face the opposite issue at JPL.. Supporting 20 year old hardware in space (which is pretty benign) or more to the point some ground testbed that replicates it. The flight hardware or prototype probably isn't the problem, it's the Apple II computer hooked up to it in the testbed that gives you diagnostic information, or is used to generate the software builds using a program that runs on the Microsoft BASIC card installed in that Apple. (or Rocky Mountain Basic on that HP calculator, or...) From mspencer12345 at yahoo.ca Thu Nov 19 16:23:07 2009 From: mspencer12345 at yahoo.ca (Mark Spencer) Date: Thu, 19 Nov 2009 08:23:07 -0800 (PST) Subject: [time-nuts] Rubidium standard / MTBF In-Reply-To: References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> <1231b6a80911190109n415ed618h3542b180f20a5b2a@mail.gmail.com> Message-ID: <330621.91677.qm@web38805.mail.mud.yahoo.com> With regards to the MTBF for internet equipment the air temperature will play a large role in determining the life span of equipment in data centers.??? There is a lot of discussion in the IT world now about raising the typical temperatures in data centers to save energy and the resulting decrease in equipment life is generally accepted.?? As IT equipment is often able to be duplicated the consequences of a single piece of equipment failing may not be very severe and it may be replaced under a?maintenance contract in any event. ? The equipment vendors typically specify operating temperatures that are considerably higher than room temperature. ? ----- Original Message ---- From: Bob Camp To: Discussion of precise time and frequency measurement Sent: Thu, November 19, 2009 4:56:27 AM Subject: Re: [time-nuts] Rubidium standard / MTBF Hi Just to put some numbers on this stuff: A typical TV has a design goal of a > 5 year lifetime. A "premium" TV has a design goal of a > 10 year lifetime. The theory is that if it doesn't last that long, the customer will not buy another one from your brand. Here in the US, most cell phones get swapped at the end of the two year contract. It's a real good bet that they are designed to have a 2 year lifespan at around the 90 to 95% level. Again, same theory, if it dies we won't sell another one. I suspect the return rate also gets written into the contracts with the carriers. There are a whole lot of normal use assumptions in their calculations. You could debate the details for a *long* time. The one that I find the most shocking is the very major internet hardware company that considers 5 years of continuos use to be the goal. The logic - we want them to swap out the gear regularly.... Bottom line - your TV may be more reliable than your internet connection ... Crazy stuff Bob On Nov 19, 2009, at 4:09 AM, Steve Rooke wrote: > 2009/11/19 Mike S : >> At 05:22 AM 11/18/2009, Steve Rooke wrote... >>> >>> The point I should have made is that most quoted MTBF figures have a >>> reasonable bearing on the lifetime of the item, >> >> But your point would then be almost perfectly incorrect. MTBFs are not meant >> to, nor do they, predict product lifetimes. They are measures/predictions of >> product reliability. > > OK, I agree, the term is mean time between failures but the question > is what is the lifetime of something. This is the point we are > discussing and we really need to understand what this means. I'm not > going to quote a number of web searches, this means different things > to different people but this matter is not quite as black and while as > you think. > > The lifetimes of any thing can be broadly split into two groups, there > are things that have a predetermined lifespan, like lifeforms, and > those that have no fixed lifespan. Let's look at the second broad > category, as this is what we are really talking about. So what is the > lifetime of an item in this category, is it related to MTBF or not. > Well, lets see, take some items, like consumer goods, these are > frequently thrown away when they fail as it is generally expensive to > fix them and newer models are more attractive. Now, do all consumers > wait till an item fails before they throw it away, well no, it depends > on the culture but I bet a large proportion of consumers probably do > wait till it fails. So in this case, quite a large section of what we > are talking about, the lifetime of the item is related to the time it > fails. Infant failures are obviously covered by initial warranty but > this seems to indicate that for a large sample size, the products > lifetime would be related to the MTBF. Agreed there are some > assumptions there, I expect the MTBF of a cellphone is a reasonable > amount but if you live in California and are seen with one over 6 > months old you would die of embarrassment. So the lifespan of a > cellphone in California is significanly shorter than the MTBF, the > factor here is the MTBE (mean time before embarrassment). > > No lets look at the corporate environment. In this environment, > failure of equipment can be very costly to a company so, if they have > any sense, they will arange to upgrade equipment well inside the time > that the item is expected to fail. Now, you may say that companies do > this well inside a shorter cycle than this as they can amortise the > cost off on tax release over a few years but I've worked in this > industry long enough to know that budgets don't work that way in the > real world and items get replaced when they fail. Again, with a large > sample size, this equates the lifetime of an item with the MTBF. > > Now, there are those industries that do upgrade their things before > they fail and including those things that have actually failed and > been replaced, these things become available to people like us. Now, > for us, the MTBF is not the relevant factor here as we will repair the > thing, over and over again so it has a lifetime far in excess of it's > MTBF. > > So, for the majority of cases in consumer an corporate usage, the > lifespan of any thing is related to the MTBF. For the smart set with > enough dosh, the lifespan of any thing is shorter than the MTBF, and > for the poor buggers like, at least, some of us, the lifespan is > greater then the MTBF. The point being that for the majority of cases, > the lifespan of any item is related to it's MTBF for equivalent sample > size. > > Now, I know that MTBF is related to the failure rate but failures > determine the lifespan of any thing in the majority of cases. > > The guys that put people into space have to really understand that > well. It's no good putting people into space for a 2 week mission in > equipment that has an expected MTBF of 1 week unless you wish the > mission to be only half completed given a sufficient sample size. It > also causes a lot of paper work and hot air to be blown which is > generally undesireable. > >> "What does MTBF have to do with lifetime?? Nothing at all!" - >> http://www.ece.cmu.edu/~ganger/ece546.spring02/readings/mtbf.description >> >> "MTBF represents the statistical approximation of how long a number of units >> should operate before a failure can be expected. It is expressed in hours >> and does not represent how long the unit will last." - Learn (or review) the >> difference between MTBF and lifetime, Control Engineering, 9/24/2008; >> http://www.controleng.com/article/312365-Learn_or_review_the_difference_between_MTBF_and_lifetime.php > > But all this means on whether you consider the lifespan of any item to > be greater than the MTBF, IE. you don't mind the possibility of having > to fix it a few times, or if you throw it out as soon as it fails, IE > lifespan is related to MTBF. This, of course, does not cover instances > for when there is a planned obsolescence of the item, then the > lifespan is shorter than the MTBF but the swap out cycle has probably > been planned from the MTBF in the first place. > >> I don't grant Wikipedia strong authority, but it is useful, and has this to >> say: "MTBF is commonly confused with a component's useful life, even though >> the two concepts are not related in any way. For example a battery may have >> a useful life of four hours, and an MTBF of 100,000 hours. These figures >> indicate that in a population of 100,000 batteries, there will be >> approximately one battery failure every hour during a single battery's >> four-hour life span." > > This is an example of an item with a specific lifespan and therefore > MTBF is not related to a single items lifespan. In this case it > determines the probability of failure of any item. Comparing the > lifespan of items having a specific lifespan with their MTBF is like > comparing apples with oranges. This is a bad example of what we were > talking about. I agree that rb lamps do have a limited life but they > can be replaced as they are just a component that fails in the actual > whole item and this is just one failure in the terms of MTBF. > >> There's much more out there, if you make the effort. > > And there is much more in you if you logically think about it instead > of just accepting things on the web without really thinking what we > are relating to here. > >>> I felt that an example based on humans was not really applicable to >>> the real world of electronic items but that is my own opinion and I'm >>> happy if you disagree with me. >> >> MTBFs are not exclusive to electronics. Statistics, math and MTBFs are >> objective matters, so your opinion really doesn't make any difference. > > Certainly statistics, math and MTBFs are objective and they have a > specific bearing on this matter. Along with this, you need to add > policy, as to how the entity using an item sees about its lifetime > related to those objectives, IE. they are related. The lifetime of > anything is a policy decision based on the items failure rate. > > Steve > -- > Steve Rooke - ZL3TUV & G8KVD > A man with one clock knows what time it is; > A man with two clocks is never quite sure. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __________________________________________________________________ Make your browsing faster, safer, and easier with the new Internet Explorer? 8. Optimized for Yahoo! Get it Now for Free! at http://downloads.yahoo.com/ca/internetexplorer/ From djl at montana.com Thu Nov 19 18:48:47 2009 From: djl at montana.com (Don Latham) Date: Thu, 19 Nov 2009 11:48:47 -0700 (MST) Subject: [time-nuts] funky frequency Message-ID: <8956c301574010bcac4fdc48f8372d9a.squirrel@webmail.montana.com> I just found in my dusty junk, a couple of ovenized frequency sources at 5.199155 MHz, part# EROS-750-MA111 Dunno why I got these. Is this a magic frequency? It does not seem to divide down to a baudrate... Don -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From mikes at flatsurface.com Thu Nov 19 18:55:00 2009 From: mikes at flatsurface.com (Mike S) Date: Thu, 19 Nov 2009 13:55:00 -0500 Subject: [time-nuts] Rubidium standard / MTBF In-Reply-To: References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> <1231b6a80911190109n415ed618h3542b180f20a5b2a@mail.gmail.com> Message-ID: <20091119185542.E3A131165C2@hamburg.alientech.net> At 07:56 AM 11/19/2009, Bob Camp wrote... >A typical TV has a design goal of a > 5 year lifetime. A "premium" TV >has a design goal of a > 10 year lifetime. The theory is that if it >doesn't last that long, the customer will not buy another one from >your brand. An even more extreme example might a simple automotive oil filter. Design life of a few hundred hours, but needs a very high MTBF, because if the filter fails, the engine may not be far behind. From lists at cq.nu Thu Nov 19 22:59:23 2009 From: lists at cq.nu (Bob Camp) Date: Thu, 19 Nov 2009 17:59:23 -0500 Subject: [time-nuts] Rubidium standard / MTBF In-Reply-To: References: Message-ID: Hi One of the reasons we use 10 to 20 year old designs in the space products is that we know they'll work for 10 to 20 years .... Bob On Nov 19, 2009, at 10:17 AM, Lux, Jim (337C) wrote: > > > > On 11/19/09 4:56 AM, "Bob Camp" wrote: > >> Hi >> >> The one that I find the most shocking is the very major internet hardware >> company that considers 5 years of continuos use to be the goal. The logic - we >> want them to swap out the gear regularly.... > > That's actually reasonable.. Moore's law is always advancing, performance is > improving, and regular swaps avoid needing to support old versions for long > times. A pretty simple financial analysis shows what the optimum plan would > be, and I'm sure that's what the MIHC does. > > We face the opposite issue at JPL.. Supporting 20 year old hardware in space > (which is pretty benign) or more to the point some ground testbed that > replicates it. The flight hardware or prototype probably isn't the problem, > it's the Apple II computer hooked up to it in the testbed that gives you > diagnostic information, or is used to generate the software builds using a > program that runs on the Microsoft BASIC card installed in that Apple. (or > Rocky Mountain Basic on that HP calculator, or...) > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From lists at cq.nu Thu Nov 19 23:03:20 2009 From: lists at cq.nu (Bob Camp) Date: Thu, 19 Nov 2009 18:03:20 -0500 Subject: [time-nuts] Rubidium standard / MTBF In-Reply-To: <330621.91677.qm@web38805.mail.mud.yahoo.com> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> <1231b6a80911190109n415ed618h3542b180f20a5b2a@mail.gmail.com> <330621.91677.qm@web38805.mail.mud.yahoo.com> Message-ID: <02F5F9D1-7CCA-4855-A731-7DA121B5DBA6@cq.nu> Hi Generally it's the magnetic stuff (like disk drives, not much core memory in use anymore ...) that limits your upper temperature in a given installation. I've lost far more disks to high temperature issues than just about everything else combined. Number two on the list would be power supplies in my case. I suspect that lightning may be involved in some of those. Bob On Nov 19, 2009, at 11:23 AM, Mark Spencer wrote: > With regards to the MTBF for internet equipment the air temperature will play a large role in determining the life span of equipment in data centers. There is a lot of discussion in the IT world now about raising the typical temperatures in data centers to save energy and the resulting decrease in equipment life is generally accepted. As IT equipment is often able to be duplicated the consequences of a single piece of equipment failing may not be very severe and it may be replaced under a maintenance contract in any event. > > The equipment vendors typically specify operating temperatures that are considerably higher than room temperature. > > > > > ----- Original Message ---- > From: Bob Camp > To: Discussion of precise time and frequency measurement > Sent: Thu, November 19, 2009 4:56:27 AM > Subject: Re: [time-nuts] Rubidium standard / MTBF > > Hi > > Just to put some numbers on this stuff: > > A typical TV has a design goal of a > 5 year lifetime. A "premium" TV has a design goal of a > 10 year lifetime. The theory is that if it doesn't last that long, the customer will not buy another one from your brand. > > Here in the US, most cell phones get swapped at the end of the two year contract. It's a real good bet that they are designed to have a 2 year lifespan at around the 90 to 95% level. Again, same theory, if it dies we won't sell another one. I suspect the return rate also gets written into the contracts with the carriers. > > There are a whole lot of normal use assumptions in their calculations. You could debate the details for a *long* time. > > The one that I find the most shocking is the very major internet hardware company that considers 5 years of continuos use to be the goal. The logic - we want them to swap out the gear regularly.... > > Bottom line - your TV may be more reliable than your internet connection ... > > Crazy stuff > > Bob > > > On Nov 19, 2009, at 4:09 AM, Steve Rooke wrote: > >> 2009/11/19 Mike S : >>> At 05:22 AM 11/18/2009, Steve Rooke wrote... >>>> >>>> The point I should have made is that most quoted MTBF figures have a >>>> reasonable bearing on the lifetime of the item, >>> >>> But your point would then be almost perfectly incorrect. MTBFs are not meant >>> to, nor do they, predict product lifetimes. They are measures/predictions of >>> product reliability. >> >> OK, I agree, the term is mean time between failures but the question >> is what is the lifetime of something. This is the point we are >> discussing and we really need to understand what this means. I'm not >> going to quote a number of web searches, this means different things >> to different people but this matter is not quite as black and while as >> you think. >> >> The lifetimes of any thing can be broadly split into two groups, there >> are things that have a predetermined lifespan, like lifeforms, and >> those that have no fixed lifespan. Let's look at the second broad >> category, as this is what we are really talking about. So what is the >> lifetime of an item in this category, is it related to MTBF or not. >> Well, lets see, take some items, like consumer goods, these are >> frequently thrown away when they fail as it is generally expensive to >> fix them and newer models are more attractive. Now, do all consumers >> wait till an item fails before they throw it away, well no, it depends >> on the culture but I bet a large proportion of consumers probably do >> wait till it fails. So in this case, quite a large section of what we >> are talking about, the lifetime of the item is related to the time it >> fails. Infant failures are obviously covered by initial warranty but >> this seems to indicate that for a large sample size, the products >> lifetime would be related to the MTBF. Agreed there are some >> assumptions there, I expect the MTBF of a cellphone is a reasonable >> amount but if you live in California and are seen with one over 6 >> months old you would die of embarrassment. So the lifespan of a >> cellphone in California is significanly shorter than the MTBF, the >> factor here is the MTBE (mean time before embarrassment). >> >> No lets look at the corporate environment. In this environment, >> failure of equipment can be very costly to a company so, if they have >> any sense, they will arange to upgrade equipment well inside the time >> that the item is expected to fail. Now, you may say that companies do >> this well inside a shorter cycle than this as they can amortise the >> cost off on tax release over a few years but I've worked in this >> industry long enough to know that budgets don't work that way in the >> real world and items get replaced when they fail. Again, with a large >> sample size, this equates the lifetime of an item with the MTBF. >> >> Now, there are those industries that do upgrade their things before >> they fail and including those things that have actually failed and >> been replaced, these things become available to people like us. Now, >> for us, the MTBF is not the relevant factor here as we will repair the >> thing, over and over again so it has a lifetime far in excess of it's >> MTBF. >> >> So, for the majority of cases in consumer an corporate usage, the >> lifespan of any thing is related to the MTBF. For the smart set with >> enough dosh, the lifespan of any thing is shorter than the MTBF, and >> for the poor buggers like, at least, some of us, the lifespan is >> greater then the MTBF. The point being that for the majority of cases, >> the lifespan of any item is related to it's MTBF for equivalent sample >> size. >> >> Now, I know that MTBF is related to the failure rate but failures >> determine the lifespan of any thing in the majority of cases. >> >> The guys that put people into space have to really understand that >> well. It's no good putting people into space for a 2 week mission in >> equipment that has an expected MTBF of 1 week unless you wish the >> mission to be only half completed given a sufficient sample size. It >> also causes a lot of paper work and hot air to be blown which is >> generally undesireable. >> >>> "What does MTBF have to do with lifetime? Nothing at all!" - >>> http://www.ece.cmu.edu/~ganger/ece546.spring02/readings/mtbf.description >>> >>> "MTBF represents the statistical approximation of how long a number of units >>> should operate before a failure can be expected. It is expressed in hours >>> and does not represent how long the unit will last." - Learn (or review) the >>> difference between MTBF and lifetime, Control Engineering, 9/24/2008; >>> http://www.controleng.com/article/312365-Learn_or_review_the_difference_between_MTBF_and_lifetime.php >> >> But all this means on whether you consider the lifespan of any item to >> be greater than the MTBF, IE. you don't mind the possibility of having >> to fix it a few times, or if you throw it out as soon as it fails, IE >> lifespan is related to MTBF. This, of course, does not cover instances >> for when there is a planned obsolescence of the item, then the >> lifespan is shorter than the MTBF but the swap out cycle has probably >> been planned from the MTBF in the first place. >> >>> I don't grant Wikipedia strong authority, but it is useful, and has this to >>> say: "MTBF is commonly confused with a component's useful life, even though >>> the two concepts are not related in any way. For example a battery may have >>> a useful life of four hours, and an MTBF of 100,000 hours. These figures >>> indicate that in a population of 100,000 batteries, there will be >>> approximately one battery failure every hour during a single battery's >>> four-hour life span." >> >> This is an example of an item with a specific lifespan and therefore >> MTBF is not related to a single items lifespan. In this case it >> determines the probability of failure of any item. Comparing the >> lifespan of items having a specific lifespan with their MTBF is like >> comparing apples with oranges. This is a bad example of what we were >> talking about. I agree that rb lamps do have a limited life but they >> can be replaced as they are just a component that fails in the actual >> whole item and this is just one failure in the terms of MTBF. >> >>> There's much more out there, if you make the effort. >> >> And there is much more in you if you logically think about it instead >> of just accepting things on the web without really thinking what we >> are relating to here. >> >>>> I felt that an example based on humans was not really applicable to >>>> the real world of electronic items but that is my own opinion and I'm >>>> happy if you disagree with me. >>> >>> MTBFs are not exclusive to electronics. Statistics, math and MTBFs are >>> objective matters, so your opinion really doesn't make any difference. >> >> Certainly statistics, math and MTBFs are objective and they have a >> specific bearing on this matter. Along with this, you need to add >> policy, as to how the entity using an item sees about its lifetime >> related to those objectives, IE. they are related. The lifetime of >> anything is a policy decision based on the items failure rate. >> >> Steve >> -- >> Steve Rooke - ZL3TUV & G8KVD >> A man with one clock knows what time it is; >> A man with two clocks is never quite sure. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > > __________________________________________________________________ > Make your browsing faster, safer, and easier with the new Internet Explorer? 8. Optimized for Yahoo! Get it Now for Free! at http://downloads.yahoo.com/ca/internetexplorer/ > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From lists at cq.nu Thu Nov 19 23:08:08 2009 From: lists at cq.nu (Bob Camp) Date: Thu, 19 Nov 2009 18:08:08 -0500 Subject: [time-nuts] Rubidium standard / MTBF In-Reply-To: <20091119185542.E3A131165C2@hamburg.alientech.net> References: <20091112071545.E0E93BCFC@ip-64-139-1-69.sjc.megapath.net> <06F48D49E69D48D59499345A71F41403@devoffice> <20091112125151.695AE1165C1@hamburg.alientech.net> <1231b6a80911180018i11907d0jbe89114b0bc603da@mail.gmail.com> <1231b6a80911180222n6c177a7bk90263d4e3b029655@mail.gmail.com> <20091118131845.A00C01165C1@hamburg.alientech.net> <1231b6a80911190109n415ed618h3542b180f20a5b2a@mail.gmail.com> <20091119185542.E3A131165C2@hamburg.alientech.net> Message-ID: <1B231A69-271B-4C7C-B0EE-16476773A4F4@cq.nu> Hi My favorite example in terms of life span is your refrigerator. In a sense, they run 24 hours a day, 365 days a year. You run them in the kitchen forever, move them out to the garage and they still keep running. 20 years later the typical fridge is still doing it's thing with absolutely no maintenance at all other than replacing the light. Of course there is the issue of the 20 year old piece of pizza back in that dark corner of the fridge... Bob On Nov 19, 2009, at 1:55 PM, Mike S wrote: > At 07:56 AM 11/19/2009, Bob Camp wrote... >> A typical TV has a design goal of a > 5 year lifetime. A "premium" TV has a design goal of a > 10 year lifetime. The theory is that if it doesn't last that long, the customer will not buy another one from your brand. > > An even more extreme example might a simple automotive oil filter. Design life of a few hundred hours, but needs a very high MTBF, because if the filter fails, the engine may not be far behind. > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From james.p.lux at jpl.nasa.gov Fri Nov 20 01:43:38 2009 From: james.p.lux at jpl.nasa.gov (Lux, Jim (337C)) Date: Thu, 19 Nov 2009 17:43:38 -0800 Subject: [time-nuts] funky frequency In-Reply-To: <8956c301574010bcac4fdc48f8372d9a.squirrel@webmail.montana.com> Message-ID: More likely it multiplies up to something useful. For instance, for deep space communications, older radios multiplied up something around 5 MHz to get the 2.x GHz or 8.X GHz transmit frequencies.. 9.5625 MHz * 880 gives 8415 MHz, which is in the middle of the Deep Space "space to earth" band. The corresponding earth to space frequency would be 749/880 times that. Similarly in the 2 GHz band, the ratio is 221/240. The entire system is based on the crystal frequency chosen for your channel and stuff is divided up and down. Until very recently, you got an allocation for your mission (many years in advance) and you'd order your crystals, wait a couple years for them to be delivered, then install them in your radio and tune it up. If your mission happened to use a spare radio from a previous mission, you'd hope you could use the same channel so you didn't have to get a new crystal. More at deepspace.jpl.nasa.gov/dsndocs/810-005/201/201A.pdf Not that your OCXO was used for that, but there are a remarkable number of fixed frequency systems around with oddball frequencies. I'll bet there's a lot of terrestrial microwave systems that multiplied a ovenized oscillator up to the frequency of use, and since they're on fixed allocated channels, there's no particular reason why one frequency is any better than another... They're all custom. On 11/19/09 10:48 AM, "Don Latham" wrote: > I just found in my dusty junk, a couple of ovenized frequency sources at > 5.199155 MHz, part# EROS-750-MA111 Dunno why I got these. Is this a magic > frequency? It does not seem to divide down to a baudrate... > Don > From stijena at tapko.de Fri Nov 20 09:07:20 2009 From: stijena at tapko.de (Predrag Dukic) Date: Fri, 20 Nov 2009 10:07:20 +0100 Subject: [time-nuts] funky frequency In-Reply-To: References: <8956c301574010bcac4fdc48f8372d9a.squirrel@webmail.montana.com> Message-ID: <7.0.1.0.1.20091120100545.02002ac8@tapko.de> Isn't EROS name of one of the asteroids? There was also some mission to it some time ago.... part# EROS-750-MA111 might have something with it. :)) At 02:43 20.11.2009, you wrote: >More likely it multiplies up to something useful. > >For instance, for deep space communications, older radios multiplied up >something around 5 MHz to get the 2.x GHz or 8.X GHz transmit frequencies.. >9.5625 MHz * 880 gives 8415 MHz, which is in the middle of the Deep Space >"space to earth" band. The corresponding earth to space frequency would be >749/880 times that. Similarly in the 2 GHz band, the ratio is 221/240. > >The entire system is based on the crystal frequency chosen for your channel >and stuff is divided up and down. Until very recently, you got an >allocation for your mission (many years in advance) and you'd order your >crystals, wait a couple years for them to be delivered, then install them in >your radio and tune it up. If your mission happened to use a spare radio >from a previous mission, you'd hope you could use the same channel so you >didn't have to get a new crystal. > > >More at >deepspace.jpl.nasa.gov/dsndocs/810-005/201/201A.pdf > > >Not that your OCXO was used for that, but there are a remarkable number of >fixed frequency systems around with oddball frequencies. I'll bet there's a >lot of terrestrial microwave systems that multiplied a ovenized oscillator >up to the frequency of use, and since they're on fixed allocated channels, >there's no particular reason why one frequency is any better than another... >They're all custom. > > >On 11/19/09 10:48 AM, "Don Latham" wrote: > > > I just found in my dusty junk, a couple of ovenized frequency sources at > > 5.199155 MHz, part# EROS-750-MA111 Dunno why I got these. Is this a magic > > frequency? It does not seem to divide down to a baudrate... > > Don > > > > >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >__________ Information from ESET NOD32 Antivirus, version of virus >signature database 4594 (20091111) __________ > >The message was checked by ESET NOD32 Antivirus. > >http://www.eset.com From eb4apl at cembreros.jazztel.es Fri Nov 20 15:58:22 2009 From: eb4apl at cembreros.jazztel.es (EB4APL) Date: Fri, 20 Nov 2009 16:58:22 +0100 Subject: [time-nuts] funky frequency In-Reply-To: <7.0.1.0.1.20091120100545.02002ac8@tapko.de> References: <8956c301574010bcac4fdc48f8372d9a.squirrel@webmail.montana.com> <7.0.1.0.1.20091120100545.02002ac8@tapko.de> Message-ID: <4B06BC9E.6020103@cembreros.jazztel.es> No, EROS was an oscillator manufacturer named Electronic Research Co, now INFICON EDC (www.electrodynamics.com). I have a 10 MHz TCXO which is marked EROS-600-DL-5-730396. It used to be the reference oscillator from a Dana counter in the 70s, if my memory doesn't fail. BTW, I'll appreciate any info on my unit. Best regards Ignacio, EB4APL ..................................................................... Predrag Dukic wrote: > > > > Isn't EROS name of one of the asteroids? There was also some mission > to it > > some time ago.... > > part# EROS-750-MA111 might have something with it. :)) > > > From david.partridge at dsl.pipex.com Fri Nov 20 16:26:57 2009 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Fri, 20 Nov 2009 16:26:57 -0000 Subject: [time-nuts] OT: Pace TJ-70 Thermojet problems and a solution Message-ID: <0DC07CC843694337AE7B7B59A1E04869@APOLLO> This is for information in case anyone else hits this problem. I bought a Pace TJ-70 Mini-Thermojet second hand not long ago, and even though it appeared hardly used (if at all) from the colour of the heater, it wouldn't melt solder or burn tissue paper as decribed in the manual even though it seemed to be heating OK. Both the heater element and the PT-100 sensor had the right resistance at room temperature. A few days back I bought a job lot of "stuff" off eBay, and it arrived this afternoon. In amongst this lot by chance was an unused heater for a TJ-70! There was however a very noticeable difference between the two heaters. The NOS one had a screw head completely blocking the bore of the heater, and when I unscrewed it, it turned out to be a flow restrictor that forces the airflow against the element. The other one doesn't have this restrictor, and even more strange there are no threads in the bore of the heater to take one. The good news is that the heater with the flow restrictor works fine. I put a call in to Pace UK to try to find out what's going on here. Dave From joegeller at roadrunner.com Sat Nov 21 02:24:24 2009 From: joegeller at roadrunner.com (Joe Geller) Date: Fri, 20 Nov 2009 21:24:24 -0500 Subject: [time-nuts] More Surplus Z3801As Message-ID: <20091120212424.425489@nectarine> There seems to be another round of surplus hp Z3801As on eBay. I bought one (no affiliation with seller) and just finished the AD6A RS-232 mod. It seems to be coming to life fine; it is from Puerto Rico. The case has less scratches than the first two I picked up back around 2002 or 03. I called the seller to see if there might be enough to make it worth discussing a group buy, however it looks like there might only be about 5 units (they are still going through pallets from a bankruptcy acquisition). http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330378532023 From iovane at inwind.it Sat Nov 21 14:05:12 2009 From: iovane at inwind.it (iovane at inwind.it) Date: Sat, 21 Nov 2009 15:05:12 +0100 (CET) Subject: [time-nuts] OT - GPS and North Message-ID: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Does a stationary (not in motion) GPS receiver know where the North is? As far as I can understand, it doesn't, isn't it? Antonio I8IOV From aa8k at comcast.net Sat Nov 21 14:20:08 2009 From: aa8k at comcast.net (Mike Naruta AA8K) Date: Sat, 21 Nov 2009 09:20:08 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: <4B07F718.4050704@comcast.net> That is an interesting question. It could be possible if it had two antennas or its antenna was not omni-directional. Mike - AA8K iovane at inwind.it wrote: > Does a stationary (not in motion) GPS receiver know where the North is? > > As far > as I can understand, it doesn't, isn't it? > > Antonio I8IOV > From magnus at rubidium.dyndns.org Sat Nov 21 14:22:20 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 21 Nov 2009 15:22:20 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: <4B07F79C.5090609@rubidium.dyndns.org> iovane at inwind.it wrote: > Does a stationary (not in motion) GPS receiver know where the North is? > > As far > as I can understand, it doesn't, isn't it? Not one with a unidirectional antenna, which is the usual stuff. If you have multiple antennas you can sort out the directions. But it is an expensive way of achieving it. If your antenna moves you can detect the heading relative north. A sensor to sense the magnetic field is fairly inexpensive so that is being used. Cheers, Magnus From rdarlington at gmail.com Sat Nov 21 14:30:48 2009 From: rdarlington at gmail.com (Robert Darlington) Date: Sat, 21 Nov 2009 07:30:48 -0700 Subject: [time-nuts] OT - GPS and North In-Reply-To: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: It depends on the GPS receiver. The GPS chipset won't know (it knows where it is and can remember where it was to know what direction it's moving), but some consumer GPS receivers (Garmin, Magellan) have electronic compasses built in. My Garmin eTrex Legend does NOT have a compass built in, but taking about 2 steps in any direction will tell me which way I'm moving. It can't do this when stationary. My buddy's eTrex can point north without moving, but that feature drains the battery faster. -Bob On Sat, Nov 21, 2009 at 7:05 AM, iovane at inwind.it wrote: > Does a stationary (not in motion) GPS receiver know where the North is? > > As far > as I can understand, it doesn't, isn't it? > > Antonio I8IOV > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From magnus at rubidium.dyndns.org Sat Nov 21 15:05:38 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 21 Nov 2009 16:05:38 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: <4B0801C2.1090601@rubidium.dyndns.org> Robert Darlington wrote: > It depends on the GPS receiver. The GPS chipset won't know (it knows where > it is and can remember where it was to know what direction it's moving), but > some consumer GPS receivers (Garmin, Magellan) have electronic compasses > built in. My Garmin eTrex Legend does NOT have a compass built in, but > taking about 2 steps in any direction will tell me which way I'm moving. It > can't do this when stationary. My buddy's eTrex can point north without > moving, but that feature drains the battery faster. The actual GPS receiver and the navigator is two different things. A GPS navigator may use additional sensors such as accelerometers and magnetic sensor to aid in addition to the GPS receiver built into them. So a navigator may know, even if on a fixed location, but the GPS receiver does not have that information. It is important to keep these separated so that they can be discussed properly. I don't want to say stuff like "The actual GPS receiver in the GPS receiver...". Cheers, Magnus From usenet at teply.info Sat Nov 21 16:30:39 2009 From: usenet at teply.info (Florian Teply) Date: Sat, 21 Nov 2009 17:30:39 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: <200911211730.40082.usenet@teply.info> Am Saturday 21 November 2009 15:05:12 schrieb iovane at inwind.it: > Does a stationary (not in motion) GPS receiver know where the North is? > > As far > as I can understand, it doesn't, isn't it? > Umm, as far as i understand it, a single receiver with a single omnidirectional antenna (at least with rotational symmetry around the vertical axis) can't know where north is. IF you just so happen to have a more clever setup, this indeed becomes possible. Basically, a GPS receiver happens to not compute his own location but the one of his antenna. So if you happen to have a receiver with enough correlators and stuff to properly connect two (or more) antennas and calculate positions for both, it could actually deduce true north. Bearings get better the more space you have between the antennas and the more averaging you can apply. Time for averaging doesn't seem much of an issue in a truly stationary setup, so just try to maximize separation of your antennas. HTH, Florian From tvb at LeapSecond.com Sat Nov 21 17:47:52 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Sat, 21 Nov 2009 09:47:52 -0800 Subject: [time-nuts] OT - GPS and North References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: > Does a stationary (not in motion) GPS receiver know where the North is? No, a stationary object is a point, not a line or a vector. The notion of North (or any direction) has no meaning to a point, by definition. There are two exceptions. If during your long polar trek the latitude is ?90? 00' 00.0" and the longitude seems to wander all over the map then, yes, your stationary GPS receiver finally knows where North is. Examples: http://www.klipsi.ch/at_Northpole/at_Northpole.htm http://www.icetent.com/south_pole.htm http://www.4x4offroads.com/south-pole-expedition-world-record.html /tvb From michael.cook at wanadoo.fr Sat Nov 21 17:56:35 2009 From: michael.cook at wanadoo.fr (mike cook) Date: Sat, 21 Nov 2009 18:56:35 +0100 Subject: [time-nuts] OT - GPS and North References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B0801C2.1090601@rubidium.dyndns.org> Message-ID: <002c01ca6ad3$f83afea0$3401a8c0@solectron> ----- Original Message ----- From: "Magnus Danielson" To: "Discussion of precise time and frequency measurement" Sent: Saturday, November 21, 2009 4:05 PM Subject: Re: [time-nuts] OT - GPS and North > > Robert Darlington wrote: >> It depends on the GPS receiver. The GPS chipset won't know (it knows >> where >> it is and can remember where it was to know what direction it's moving), >> but >> some consumer GPS receivers (Garmin, Magellan) have electronic compasses >> built in. My Garmin eTrex Legend does NOT have a compass built in, but >> taking about 2 steps in any direction will tell me which way I'm moving. >> It >> can't do this when stationary. My buddy's eTrex can point north without >> moving, but that feature drains the battery faster. > > The actual GPS receiver and the navigator is two different things. A GPS > navigator may use additional sensors such as accelerometers and magnetic > sensor to aid in addition to the GPS receiver built into them. > Agreed Magnus, but I dont think any gizmos are required. If the the positions of the satellites are known, as they must be to enable the antennas position to be calculated, I think just an extra set of calculations is necessary to indicate the direction to anywhere else on the planet (or elsewhere) including the geographic poles. Getting the magnetic pole directions would need something else I suppose. > So a navigator may know, even if on a fixed location, but the GPS receiver > does not have that information. > > It is important to keep these separated so that they can be discussed > properly. I don't want to say stuff like "The actual GPS receiver in the > GPS receiver...". > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From hmurray at megapathdsl.net Sat Nov 21 18:25:00 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sat, 21 Nov 2009 10:25:00 -0800 Subject: [time-nuts] OT - GPS and North In-Reply-To: Message from "mike cook" of "Sat, 21 Nov 2009 18:56:35 +0100." <002c01ca6ad3$f83afea0$3401a8c0@solectron> Message-ID: <20091121182501.80615BCFC@ip-64-139-1-69.sjc.megapath.net> > Agreed Magnus, but I dont think any gizmos are required. If the the > positions of the satellites are known, as they must be to enable the > antennas position to be calculated, I think just an extra set of > calculations is necessary to indicate the direction to anywhere else > on the planet (or elsewhere) including the geographic poles. Getting > the magnetic pole directions would need something else I suppose. I think that only works if your antenna is bigger than a point source. Consider the simple case of a car radio. Which way is the transmitter? If you have a directional antenna, say a yagi or dish for your TV, you can figure out what direction the signal is coming from by rotating the antenna and measuring the signal strength. With multiple antennas you can use phased array techniques. -- These are my opinions, not necessarily my employer's. I hate spam. From magnus at rubidium.dyndns.org Sat Nov 21 18:32:47 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 21 Nov 2009 19:32:47 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: <4B08324F.4070302@rubidium.dyndns.org> Tom Van Baak wrote: >> Does a stationary (not in motion) GPS receiver know where the North is? > > No, a stationary object is a point, not a line or a vector. > The notion of North (or any direction) has no meaning > to a point, by definition. You are mixing things a litte too much here. There is no direction within a 0-dimensional space, but a point as it is positioned in a 3-dimensional space has no problem to have an associated vector pointing either to a location or along some field such as the magnetic field. An electron is a point-charge, and reacts to a magnetic field or the electrostatic field. The antenna is certainly not a point, it is a sizeable object and it's phase centrum isn't a point either, it's just a handy approximation. It's just that normal GPS antennas and receivers isn't built for this purpose. A much smaller object than either the antenna or the receiver is the SO-8 packaged magnetic sensor you can buy cheaply and sense the magnetic field. A GPS receiver can be used to compensate for magnetic deviation if needed. Cheers, Magnus From magnus at rubidium.dyndns.org Sat Nov 21 18:43:59 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 21 Nov 2009 19:43:59 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <002c01ca6ad3$f83afea0$3401a8c0@solectron> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B0801C2.1090601@rubidium.dyndns.org> <002c01ca6ad3$f83afea0$3401a8c0@solectron> Message-ID: <4B0834EF.1050401@rubidium.dyndns.org> mike cook wrote: > > ----- Original Message ----- From: "Magnus Danielson" > > To: "Discussion of precise time and frequency measurement" > > Sent: Saturday, November 21, 2009 4:05 PM > Subject: Re: [time-nuts] OT - GPS and North > > >> >> Robert Darlington wrote: >>> It depends on the GPS receiver. The GPS chipset won't know (it knows >>> where >>> it is and can remember where it was to know what direction it's >>> moving), but >>> some consumer GPS receivers (Garmin, Magellan) have electronic compasses >>> built in. My Garmin eTrex Legend does NOT have a compass built in, but >>> taking about 2 steps in any direction will tell me which way I'm >>> moving. It >>> can't do this when stationary. My buddy's eTrex can point north without >>> moving, but that feature drains the battery faster. >> >> The actual GPS receiver and the navigator is two different things. A >> GPS navigator may use additional sensors such as accelerometers and >> magnetic sensor to aid in addition to the GPS receiver built into them. >> > > Agreed Magnus, but I dont think any gizmos are required. If the the > positions of the satellites are known, as they must be to enable the > antennas position to be calculated, I think just an extra set of > calculations is necessary to indicate the direction to anywhere else on > the planet (or elsewhere) including the geographic poles. Getting the > magnetic pole directions would need something else I suppose. Yes, but you don't know in what direction from the unidirectional antenna. The antenna has no sense of direction, but the receiver knows very well in what direction relative north each sat is. The NMEA stream even include the coarse directions. If you has a steerable directional antenna, several antennas or moveable antenna, then you can convert the internal directions of the antenna into a north heading or heading towards anything else. But a normal unidirectional GPS antenna and associated receiver will be able to know where it is and from it provide very high precision direction relative north, but unless you move it or make any other form of aid, it will not be able to show the heading... but when you move around in with the car, then it can show it relative to the current heading of the car... as that forms a vector for which you can relate an angle... to north or to your intended destination. Cheers, Magnus From aa8k at comcast.net Sat Nov 21 19:20:25 2009 From: aa8k at comcast.net (Mike Naruta AA8K) Date: Sat, 21 Nov 2009 14:20:25 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B0834EF.1050401@rubidium.dyndns.org> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B0801C2.1090601@rubidium.dyndns.org> <002c01ca6ad3$f83afea0$3401a8c0@solectron> <4B0834EF.1050401@rubidium.dyndns.org> Message-ID: <4B083D79.2020103@comcast.net> Yes, but it is rather difficult to manufacture an isotropic antenna. Unless the antenna is oriented so as to present a normal hemisphere of same gain, it might be theoretically possible to model the gain versus direction, coupled with the knowledge of location of satellites and received strength, to determine the antenna's orientation with respect to the world. Now, there are lots of sources of error and potential ambiguities for this process. As you say, it is more straightforward to use a magnetic field sensor. With position information it should be easy to correct for true North. Mike - AA8K Magnus Danielson wrote: > > Yes, but you don't know in what direction from the unidirectional > antenna. The antenna has no sense of direction, but the receiver knows > very well in what direction relative north each sat is. The NMEA stream > even include the coarse directions. > > If you has a steerable directional antenna, several antennas or moveable > antenna, then you can convert the internal directions of the antenna > into a north heading or heading towards anything else. > > But a normal unidirectional GPS antenna and associated receiver will be > able to know where it is and from it provide very high precision > direction relative north, but unless you move it or make any other form > of aid, it will not be able to show the heading... but when you move > around in with the car, then it can show it relative to the current > heading of the car... as that forms a vector for which you can relate an > angle... to north or to your intended destination. > > Cheers, > Magnus > From tvb at LeapSecond.com Sat Nov 21 19:31:24 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Sat, 21 Nov 2009 11:31:24 -0800 Subject: [time-nuts] OT - GPS and North References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost><4B0801C2.1090601@rubidium.dyndns.org> <002c01ca6ad3$f83afea0$3401a8c0@solectron> Message-ID: <6AB847FA700E4B79AB52060DB9288341@pc52> > If the > positions of the satellites are known, as they must be to enable the > antennas position to be calculated, I think just an extra set of > calculations is necessary to indicate the direction to anywhere else on the > planet (or elsewhere) including the geographic poles. Mike, The calculations tell you where on the globe you are. Correct, from this you can easily calculate angle and distance to either pole. But the receiver cannot "indicate" this angle. Meaning if you hold a GPS antenna in your hand you may know you have to aim 75 degrees and walk 5000 km to the North pole but you still have no idea how to turn around to take that first step. A static GPS receiver is a point device, not a pointing device. On the other hand a magnetic compass is a pointing device, not a point device. That's why some navigation units combine both. If you just want to travel then as Confucius say: journey of a thousand miles begins with single step. But if you want to reach a particular destination then journey of a thousand miles must begin with single step in correct direction. ;-) /tvb From mspencer12345 at yahoo.ca Sat Nov 21 19:32:44 2009 From: mspencer12345 at yahoo.ca (Mark Spencer) Date: Sat, 21 Nov 2009 11:32:44 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B083D79.2020103@comcast.net> Message-ID: <292414.4587.qm@web38803.mail.mud.yahoo.com> Would Time Difference of Arrival techniques combined with an array of four closely spaced antennas work with Gps signals as a means of determing the orentation of the antenna array vs the gps satellites ? (I'm thinking traditional TDOA techniques may not work with gps signals.) Mike Naruta AA8K wrote: > Yes, but it is rather difficult to manufacture an > isotropic antenna. Unless the antenna is oriented > so as to present a normal hemisphere of same gain, > it might be theoretically possible to model the gain > versus direction, coupled with the knowledge of > location of satellites and received strength, to > determine the antenna's orientation with respect > to the world. > Now, there are lots of sources of error and > potential ambiguities for this process. As > you say, it is more straightforward to use a > magnetic field sensor. With position information > it should be easy to correct for true North. > Mike - AA8K > Magnus Danielson wrote: >> >> Yes, but you don't know in what direction from the unidirectional antenna. The antenna has no sense of direction, but the receiver knows very well in what direction relative north each sat is. The NMEA stream even include the coarse directions. >> >> If you has a steerable directional antenna, several antennas or moveable antenna, then you can convert the internal directions of the antenna into a north heading or heading towards anything else. >> >> But a normal unidirectional GPS antenna and associated receiver will be able to know where it is and from it provide very high precision direction relative north, but unless you move it or make any other form of aid, it will not be able to show the heading... but when you move around in with the car, then it can show it relative to the current heading of the car... as that forms a vector for which you can relate an angle... to north or to your intended destination. >> >> Cheers, >> Magnus >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. __________________________________________________________________ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now http://ca.toolbar.yahoo.com. From jfor at quik.com Sat Nov 21 19:32:11 2009 From: jfor at quik.com (J. Forster) Date: Sat, 21 Nov 2009 11:32:11 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B08324F.4070302@rubidium.dyndns.org> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> Message-ID: <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> OK. Sme GPS receivers have magnetic sensors. What do they do with/about magnetic deviation. -John ============== > Tom Van Baak wrote: >>> Does a stationary (not in motion) GPS receiver know where the North is? >> >> No, a stationary object is a point, not a line or a vector. >> The notion of North (or any direction) has no meaning >> to a point, by definition. > > You are mixing things a litte too much here. There is no direction > within a 0-dimensional space, but a point as it is positioned in a > 3-dimensional space has no problem to have an associated vector pointing > either to a location or along some field such as the magnetic field. > > An electron is a point-charge, and reacts to a magnetic field or the > electrostatic field. > > The antenna is certainly not a point, it is a sizeable object and it's > phase centrum isn't a point either, it's just a handy approximation. > > It's just that normal GPS antennas and receivers isn't built for this > purpose. A much smaller object than either the antenna or the receiver > is the SO-8 packaged magnetic sensor you can buy cheaply and sense the > magnetic field. A GPS receiver can be used to compensate for magnetic > deviation if needed. > > Cheers, > Magnus From SAIDJACK at aol.com Sat Nov 21 19:40:40 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sat, 21 Nov 2009 14:40:40 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: Hi guys, some weeks ago we talked about reception problems on Trimble Thunderbolt units. I finally took the time to download the Trimble monitor again, and get my unit locked again. Here is what I found: The unit was running continuously for the last months, but wasn't locked. Using the Trimble monitor, I restarted the unit, now connected directly to my antenna, then after the survey was done let it run from my antenna splitter. This works, but just barely. I use an Agilent 58512A amp, followed by a Mini Circuits ZB4PD1-152-75+ 1-to-4 passive splitter. In the attached plot a JLT FireFly-IIA and the Thunderbolt are both running from the same Mini Circuits splitter. The Antenna sense circuit in the Thunderbolt is happy, but the signal strength is just at the threshold of working. The Sats kick in and out. Please see the attached screen shot. At the same time the FireFly-IIA receiver is tracking 11 Sats with perfect signal strengths (up to 45dB+ C/No), from the same feed. The difference in receiver performance is quite clear. Unfortunately I have only a single antenna, so need to run the Thunderbolt from a splitter. One can also see two more interesting tid-bits in the screen shot: the FireFly-IIA is tracking and using WAAS Sat PRN 48 (PRN 51 goes in and out of lo ck due to a chimney being in the way), and it is showing true MSL rather than just GPS Height. Thanks for the help, bye, Said -------------- next part -------------- A non-text attachment was scrubbed... Name: trimble_sats.gif Type: image/gif Size: 61587 bytes Desc: not available URL: From jfor at quik.com Sat Nov 21 19:38:56 2009 From: jfor at quik.com (J. Forster) Date: Sat, 21 Nov 2009 11:38:56 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <292414.4587.qm@web38803.mail.mud.yahoo.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> Message-ID: <1934.12.6.201.171.1258832336.squirrel@popacctsnew.quik.com> Clearly, two three antennas can tell you everything you need to know. I've seen video of a model helicopter flying itself with three GPS antennas. NASA, I think. -John =========== > Would Time Difference of Arrival techniques combined with an array of four > closely spaced antennas work with Gps signals as a means of determing the > orentation of the antenna array vs the gps satellites ? (I'm thinking > traditional TDOA techniques may not work with gps signals.) From aa8k at comcast.net Sat Nov 21 19:58:04 2009 From: aa8k at comcast.net (Mike Naruta AA8K) Date: Sat, 21 Nov 2009 14:58:04 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <6AB847FA700E4B79AB52060DB9288341@pc52> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost><4B0801C2.1090601@rubidium.dyndns.org> <002c01ca6ad3$f83afea0$3401a8c0@solectron> <6AB847FA700E4B79AB52060DB9288341@pc52> Message-ID: <4B08464C.7040803@comcast.net> Tom, this would be taking advantage of the irregularities of the GPS receive antenna to determine the orientation of the antenna. For example, if the GPS antenna were a Yagi, and it was pointed with the major lobe in an Easterly direction, when you listen to a satellite in the East, you know it's location and you can observe a high signal strength. A satellite in the West might have a low signal strength, or be missing. Now this thought experiment is loaded with issues; for example, external attenuation, multi-path, multiple lobes, small gain differences, etc., but we're just having fun here. Mike - AA8K Tom Van Baak wrote: > > Mike, > > The calculations tell you where on the globe you are. Correct, > from this you can easily calculate angle and distance to either > pole. > > But the receiver cannot "indicate" this angle. Meaning if you > hold a GPS antenna in your hand you may know you have > to aim 75 degrees and walk 5000 km to the North pole but you > still have no idea how to turn around to take that first step. > > A static GPS receiver is a point device, not a pointing device. > On the other hand a magnetic compass is a pointing device, > not a point device. That's why some navigation units combine > both. > > If you just want to travel then as Confucius say: journey of a > thousand miles begins with single step. But if you want to > reach a particular destination then journey of a thousand > miles must begin with single step in correct direction. ;-) > > /tvb > > From djl at montana.com Sat Nov 21 20:39:54 2009 From: djl at montana.com (Don Latham) Date: Sat, 21 Nov 2009 13:39:54 -0700 (MST) Subject: [time-nuts] funky frequency In-Reply-To: <4B06BC9E.6020103@cembreros.jazztel.es> References: <8956c301574010bcac4fdc48f8372d9a.squirrel@webmail.montana.com> <7.0.1.0.1.20091120100545.02002ac8@tapko.de> <4B06BC9E.6020103@cembreros.jazztel.es> Message-ID: Apparently, I was goi9ng in the wrong direction... Don BTW, I do have a pinout for your tcxo, I think, if it is the same as the 5.11etc. Don EB4APL > No, EROS was an oscillator manufacturer named Electronic Research Co, > now INFICON EDC (www.electrodynamics.com). > I have a 10 MHz TCXO which is marked EROS-600-DL-5-730396. It used to > be the reference oscillator from a Dana counter in the 70s, if my memory > doesn't fail. > BTW, I'll appreciate any info on my unit. > > Best regards > Ignacio, EB4APL > ..................................................................... > Predrag Dukic wrote: >> >> >> >> Isn't EROS name of one of the asteroids? There was also some mission >> to it >> >> some time ago.... >> >> part# EROS-750-MA111 might have something with it. :)) >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From warrensjmail-one at yahoo.com Sat Nov 21 21:19:50 2009 From: warrensjmail-one at yahoo.com (WarrenS) Date: Sat, 21 Nov 2009 13:19:50 -0800 Subject: [time-nuts] Thunderbolt reception problems References: Message-ID: <1DCFC07E71B9471AB48EBFDD5CF97EB5@WSOffice> Maybe something too basic many too say, but did you lower the Tbolts "signal level mask AMU" setting? Default is 3, set to 1 or 2 so that it will accept lower level signals ----- Original Message ----- From: To: Sent: Saturday, November 21, 2009 11:40 AM Subject: [time-nuts] Thunderbolt reception problems > Hi guys, > > some weeks ago we talked about reception problems on Trimble Thunderbolt > units. I finally took the time to download the Trimble monitor again, and get > my unit locked again. Here is what I found: > > The unit was running continuously for the last months, but wasn't locked. > Using the Trimble monitor, I restarted the unit, now connected directly to > my antenna, then after the survey was done let it run from my antenna > splitter. > > This works, but just barely. I use an Agilent 58512A amp, followed by a > Mini Circuits ZB4PD1-152-75+ 1-to-4 passive splitter. > > In the attached plot a JLT FireFly-IIA and the Thunderbolt are both running > from the same Mini Circuits splitter. The Antenna sense circuit in the > Thunderbolt is happy, but the signal strength is just at the threshold of > working. The Sats kick in and out. Please see the attached screen shot. > > At the same time the FireFly-IIA receiver is tracking 11 Sats with perfect > signal strengths (up to 45dB+ C/No), from the same feed. > > The difference in receiver performance is quite clear. Unfortunately I > have only a single antenna, so need to run the Thunderbolt from a splitter. > > One can also see two more interesting tid-bits in the screen shot: the > FireFly-IIA is tracking and using WAAS Sat PRN 48 (PRN 51 goes in and out of lo > ck due to a chimney being in the way), and it is showing true MSL rather > than just GPS Height. > > Thanks for the help, > bye, > Said > > From bg at lysator.liu.se Sat Nov 21 22:17:12 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sat, 21 Nov 2009 23:17:12 +0100 (CET) Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: Message-ID: <60741.87.227.52.225.1258841832.squirrel@webmail.lysator.liu.se> Hi Said, As we talked about some weeks ago... your test is unfair to the Tbolt, but that is perhaps intentional. The Tbolt will need more gain to work. You are giving it a signal that is out of spec. -- Bj?rn > Hi guys, > > some weeks ago we talked about reception problems on Trimble Thunderbolt > units. I finally took the time to download the Trimble monitor again, and > get > my unit locked again. Here is what I found: > > The unit was running continuously for the last months, but wasn't locked. > Using the Trimble monitor, I restarted the unit, now connected directly > to > my antenna, then after the survey was done let it run from my antenna > splitter. > > This works, but just barely. I use an Agilent 58512A amp, followed by a > Mini Circuits ZB4PD1-152-75+ 1-to-4 passive splitter. > > In the attached plot a JLT FireFly-IIA and the Thunderbolt are both > running > from the same Mini Circuits splitter. The Antenna sense circuit in the > Thunderbolt is happy, but the signal strength is just at the threshold of > working. The Sats kick in and out. Please see the attached screen shot. > > At the same time the FireFly-IIA receiver is tracking 11 Sats with perfect > signal strengths (up to 45dB+ C/No), from the same feed. > > The difference in receiver performance is quite clear. Unfortunately I > have only a single antenna, so need to run the Thunderbolt from a > splitter. > > One can also see two more interesting tid-bits in the screen shot: the > FireFly-IIA is tracking and using WAAS Sat PRN 48 (PRN 51 goes in and out > of lo > ck due to a chimney being in the way), and it is showing true MSL rather > than just GPS Height. > > Thanks for the help, > bye, > Said > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From gcarlistaa at garychatters.com Sat Nov 21 22:57:15 2009 From: gcarlistaa at garychatters.com (Gary Chatters) Date: Sat, 21 Nov 2009 17:57:15 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <292414.4587.qm@web38803.mail.mud.yahoo.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> Message-ID: <4B08704B.4020707@garychatters.com> Mark Spencer wrote: > Would Time Difference of Arrival techniques combined with an array of four closely spaced antennas work with Gps signals as a means of determing the orentation of the antenna array vs the gps satellites ? (I'm thinking traditional TDOA techniques may not work with gps signals.) > There are commercial products available: http://www.hemispheregps.com/Default.aspx?tabid=379 http://www.hemispheregps.com/Default.aspx?tabid=412 These devices claim less than 1 degree RMS heading accuracy. Here the antennas are integrated and a fixed 0.5 meter apart. They do (or did) make a board that could be used with separate antennas, but I can not find it right now. I have no idea of how the math works for computing heading. Gary From gcarlistaa at garychatters.com Sat Nov 21 23:03:05 2009 From: gcarlistaa at garychatters.com (Gary Chatters) Date: Sat, 21 Nov 2009 18:03:05 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B08704B.4020707@garychatters.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> Message-ID: <4B0871A9.9000606@garychatters.com> Gary Chatters wrote: > Mark Spencer wrote: >> Would Time Difference of Arrival techniques combined with an array of >> four closely spaced antennas work with Gps signals as a means of >> determing the orentation of the antenna array vs the gps satellites ? >> (I'm thinking traditional TDOA techniques may not work with gps >> signals.) >> > > There are commercial products available: > http://www.hemispheregps.com/Default.aspx?tabid=379 > http://www.hemispheregps.com/Default.aspx?tabid=412 > > > These devices claim less than 1 degree RMS heading accuracy. > > Here the antennas are integrated and a fixed 0.5 meter apart. They do > (or did) make a board that could be used with separate antennas, but I > can not find it right now. I think this is the one: http://www.hemispheregps.com/Products/PrecisionProductsGroup/PrecisionProducts/CrescentOEMModules/tabid/136/Default.aspx > > I have no idea of how the math works for computing heading. > From gcarlistaa at garychatters.com Sat Nov 21 23:09:30 2009 From: gcarlistaa at garychatters.com (Gary Chatters) Date: Sat, 21 Nov 2009 18:09:30 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> Message-ID: <4B08732A.8090207@garychatters.com> J. Forster wrote: > OK. Sme GPS receivers have magnetic sensors. What do they do with/about > magnetic deviation. > There is a field in one of the NMEA messages for magnetic deviation which some GPS receivers fill in. I do not know where they get the values. There is a mathematical model available from an appropriate agency (I forget which one right now) that can be used to compute magnetic deviation anywhere on earth. The model is supposed to be good for about five years before the coefficients need to be updated. Gary From iain at g7iii.net Sat Nov 21 23:10:13 2009 From: iain at g7iii.net (Iain Young) Date: Sat, 21 Nov 2009 23:10:13 +0000 Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B08704B.4020707@garychatters.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> Message-ID: <4B087355.5070307@g7iii.net> Gary Chatters wrote: > I have no idea of how the math works for computing heading. Checkout FORWARD and INVERSE (and their 3d equivalents) at http://www.ngs.noaa.gov/TOOLS/Inv_Fwd/Inv_Fwd.html While these are hosted on a NOAA site, I'm sure I've seen it on a NASA site as well. IIRC, there is also a C port somewhere. Iain From bg at lysator.liu.se Sat Nov 21 23:19:48 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 22 Nov 2009 00:19:48 +0100 (CET) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B08704B.4020707@garychatters.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> Message-ID: <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> > Mark Spencer wrote: >> Would Time Difference of Arrival techniques combined with an array of >> four closely spaced antennas work with Gps signals as a means of >> determing the orentation of the antenna array vs the gps satellites ? >> (I'm thinking traditional TDOA techniques may not work with gps >> signals.) >> > > There are commercial products available: > http://www.hemispheregps.com/Default.aspx?tabid=379 > http://www.hemispheregps.com/Default.aspx?tabid=412 > > > These devices claim less than 1 degree RMS heading accuracy. > > Here the antennas are integrated and a fixed 0.5 meter apart. They do > (or did) make a board that could be used with separate antennas, but I > can not find it right now. > > I have no idea of how the math works for computing heading. > > Gary > Any (almost) pair of GPS-receivers with phase measurement outputs can be used to make an attitude GPS receiver - sometimes called a GPS compass. You need decent antennas for good results. This is a special case of a phase ambiguity problem with moving base receiver and extremely short baseline. If the antennas are mounted at a fixed relative position, knowing the baseline gives a simpler problem. I have read papers about using only one receiver and one antenna. The trick is then to use the antenna diagram and SNR from the currently tracked satellites to estimate an orientation. I have seen no commercial product trying this. Accuracy was not spectacular - a few degrees - if I remember correctly. Would need a very stable environment to work. A groundapplication (say car moving in urban environment) will influence the received SNRs to randomly to make a one antenna approach possible. Most GPS manufacturers have attitude GPS receivers. If not dedicated its a special case for their RTK capable versions. -- Bj?rn From bg at lysator.liu.se Sat Nov 21 23:26:22 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 22 Nov 2009 00:26:22 +0100 (CET) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B08732A.8090207@garychatters.com> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <4B08732A.8090207@garychatters.com> Message-ID: <61240.87.227.52.225.1258845982.squirrel@webmail.lysator.liu.se> > J. Forster wrote: >> OK. Sme GPS receivers have magnetic sensors. What do they do with/about >> magnetic deviation. >> > > There is a field in one of the NMEA messages for magnetic deviation > which some GPS receivers fill in. > > I do not know where they get the values. There is a mathematical model > available from an appropriate agency (I forget which one right now) that > can be used to compute magnetic deviation anywhere on earth. The model > is supposed to be good for about five years before the coefficients need > to be updated. > > > Gary > One model is called the World Magnetic Model http://en.wikipedia.org/wiki/World_Magnetic_Model These models are the magnetic equivialent of the gravity models used to determine the geoid. -- Bj?rn From gcarlistaa at garychatters.com Sat Nov 21 23:29:51 2009 From: gcarlistaa at garychatters.com (Gary Chatters) Date: Sat, 21 Nov 2009 18:29:51 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B087355.5070307@g7iii.net> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <4B087355.5070307@g7iii.net> Message-ID: <4B0877EF.4020106@garychatters.com> Iain Young wrote: > Gary Chatters wrote: > >> I have no idea of how the math works for computing heading. > > Checkout FORWARD and INVERSE (and their 3d equivalents) at > http://www.ngs.noaa.gov/TOOLS/Inv_Fwd/Inv_Fwd.html > > While these are hosted on a NOAA site, I'm sure I've seen > it on a NASA site as well. IIRC, there is also a C port > somewhere. > > I am not sure that this would be useful in this application. Getting < 1 degree heading error from two positions would require about 8mm absolute accuracy. I suspect that such accuracy requires something like the phase measurements as mentioned by Bj?rn. Gary From gcarlistaa at garychatters.com Sat Nov 21 23:36:15 2009 From: gcarlistaa at garychatters.com (Gary Chatters) Date: Sat, 21 Nov 2009 18:36:15 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <61240.87.227.52.225.1258845982.squirrel@webmail.lysator.liu.se> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <4B08732A.8090207@garychatters.com> <61240.87.227.52.225.1258845982.squirrel@webmail.lysator.liu.se> Message-ID: <4B08796F.8050902@garychatters.com> bg at lysator.liu.se wrote: >> J. Forster wrote: >>> OK. Sme GPS receivers have magnetic sensors. What do they do with/about >>> magnetic deviation. >>> >> There is a field in one of the NMEA messages for magnetic deviation >> which some GPS receivers fill in. >> >> I do not know where they get the values. There is a mathematical model >> available from an appropriate agency (I forget which one right now) that >> can be used to compute magnetic deviation anywhere on earth. The model >> is supposed to be good for about five years before the coefficients need >> to be updated. >> >> >> Gary >> > > One model is called the World Magnetic Model > > http://en.wikipedia.org/wiki/World_Magnetic_Model > That is the one I was thinking of. Follow the Wikipedia link to the NGDC webpage: http://www.ngdc.noaa.gov/geomag/WMM/ New model due 15 December. Gary From namichie at gmail.com Sat Nov 21 23:38:57 2009 From: namichie at gmail.com (Neville Michie) Date: Sun, 22 Nov 2009 10:38:57 +1100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> Message-ID: When you think of time specifications from GPS, the GPS system is a poor way to find north. Even with a base line of 1000 metres you only have a fraction of a degree. The GPS system may be useful to get accurate time to simplify a star observation, from a known (GPS) position on this planet, but finding north is still a problem because of the accuracy of a small number of observations from a star fix. Gyrocompasses take some time to get a measurement ( one hour) but even their estimate of North cannot match the precision that the GPS system can get us with time. cheers, Neville Michie From mspencer12345 at yahoo.ca Sat Nov 21 23:46:49 2009 From: mspencer12345 at yahoo.ca (Mark Spencer) Date: Sat, 21 Nov 2009 15:46:49 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B08704B.4020707@garychatters.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> Message-ID: <101472.26676.qm@web38806.mail.mud.yahoo.com> Interesting thanks ! ----- Original Message ---- From: Gary Chatters To: Discussion of precise time and frequency measurement Sent: Sat, November 21, 2009 2:57:15 PM Subject: Re: [time-nuts] OT - GPS and North Mark Spencer wrote: > Would Time Difference of Arrival techniques combined with an array of four closely spaced antennas work with Gps signals as a means of determing the orentation of the antenna array vs the gps satellites ? (I'm thinking traditional TDOA techniques may not work with gps signals.) > There are commercial products available: http://www.hemispheregps.com/Default.aspx?tabid=379 http://www.hemispheregps.com/Default.aspx?tabid=412 These devices claim less than 1 degree RMS heading accuracy. Here the antennas are integrated and a fixed 0.5 meter apart.? They do (or did) make a board that could be used with separate antennas, but I can not find it right now. I have no idea of how the math works for computing heading. Gary _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __________________________________________________________________ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now http://ca.toolbar.yahoo.com. From magnus at rubidium.dyndns.org Sat Nov 21 23:59:19 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 22 Nov 2009 00:59:19 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> Message-ID: <4B087ED7.7080100@rubidium.dyndns.org> bg at lysator.liu.se wrote: >> Mark Spencer wrote: >>> Would Time Difference of Arrival techniques combined with an array of >>> four closely spaced antennas work with Gps signals as a means of >>> determing the orentation of the antenna array vs the gps satellites ? >>> (I'm thinking traditional TDOA techniques may not work with gps >>> signals.) >>> >> There are commercial products available: >> http://www.hemispheregps.com/Default.aspx?tabid=379 >> http://www.hemispheregps.com/Default.aspx?tabid=412 >> >> >> These devices claim less than 1 degree RMS heading accuracy. >> >> Here the antennas are integrated and a fixed 0.5 meter apart. They do >> (or did) make a board that could be used with separate antennas, but I >> can not find it right now. >> >> I have no idea of how the math works for computing heading. >> >> Gary >> > > Any (almost) pair of GPS-receivers with phase measurement outputs can be > used to make an attitude GPS receiver - sometimes called a GPS compass. > You need decent antennas for good results. > > This is a special case of a phase ambiguity problem with moving base > receiver and extremely short baseline. If the antennas are mounted at a > fixed relative position, knowing the baseline gives a simpler problem. By having the additional antennas hooked to the same GPS core with multiple frontends, the central antenna can act like a traditional receiver. The carrier and code tracking-loops for additional antennas can then be aided by the central antenna, which will help to reduce ambiguities. After inital ambiguities have been resolved, maintaining tracking should not be too hard. Using multiple receivers does not give the same effect as tight integration. > I have read papers about using only one receiver and one antenna. The > trick is then to use the antenna diagram and SNR from the currently > tracked satellites to estimate an orientation. I have seen no commercial > product trying this. Accuracy was not spectacular - a few degrees - if I > remember correctly. Would need a very stable environment to work. A > groundapplication (say car moving in urban environment) will influence the > received SNRs to randomly to make a one antenna approach possible. Such an approach is indeed possible but fragile. You could also include shift in phase center, in which case a "bad" antenna would be good. Knowing the orientation of the antenna could allow for post-processing to compensate for phase-shift. You would loose precission from position tracking but gain an estimate in heading. Cheers, Magnus From bg at lysator.liu.se Sun Nov 22 00:18:22 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 22 Nov 2009 01:18:22 +0100 (CET) Subject: [time-nuts] OT - GPS and North In-Reply-To: References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> Message-ID: <61403.87.227.52.225.1258849102.squirrel@webmail.lysator.liu.se> Hi Neville > When you think of time specifications from GPS, the GPS system is a > poor way to find north. I do not understand. Please elaborate. A baseline of 10 meter will often give better than 1mrad accuracy. > Even with a base line of 1000 metres you only have a fraction of a > degree. This is just not true. > The GPS system may be useful to get accurate time to simplify a star > observation, from a known (GPS) > position on this planet, but finding north is still a problem because > of the accuracy of a small > number of observations from a star fix. > Gyrocompasses take some time to get a measurement > ( one hour) but even their estimate of North cannot match the > precision that the GPS system can get us with time. While legacy mechanical gyrocompasses on a ship, might take time to converge - it does not take a modern strapdown INS more than about 4 minutes to find north while stationary. But having 4 minutes at hand with some decent GPS-receivers its easy to get a north-measurement that will be much better than the best available intertial systems. > cheers, Neville Michie -- Bj?rn From bruce.griffiths at xtra.co.nz Sun Nov 22 00:37:21 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 22 Nov 2009 13:37:21 +1300 Subject: [time-nuts] OT - GPS and North In-Reply-To: References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> Message-ID: <4B0887C1.8090009@xtra.co.nz> Neville Michie wrote: > > When you think of time specifications from GPS, the GPS system is a > poor way to find north. > Even with a base line of 1000 metres you only have a fraction of a > degree. > The GPS system may be useful to get accurate time to simplify a star > observation, from a known (GPS) > position on this planet, but finding north is still a problem because > of the accuracy of a small > number of observations from a star fix. > Gyrocompasses take some time to get a measurement > ( one hour) but even their estimate of North cannot match the > precision that the GPS system can get us with time. > cheers, Neville Michie If you are taking star shots a stellar compass can easily provide a boresight pointing accuracy of a few arcsec. Bruce From lists at cq.nu Sun Nov 22 00:53:30 2009 From: lists at cq.nu (Bob Camp) Date: Sat, 21 Nov 2009 19:53:30 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B087ED7.7080100@rubidium.dyndns.org> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> <4B087ED7.7080100@rubidium.dyndns.org> Message-ID: Hi If you only have one antenna and one receiver, the answer is fairly simple. Swing it around you head on the end of a long string. Plot the position reading vs time. Correlate the readings to the phase of the rotation. It does indeed work (it's a doppler scanner ...). You could easily argue that it's not exactly a stationary situation any more. Making it work correctly would involve a lot of work figuring out just how much lag the receiver has. You might have to swing it at a 10 rpm rate ... Bob On Nov 21, 2009, at 6:59 PM, Magnus Danielson wrote: > bg at lysator.liu.se wrote: >>> Mark Spencer wrote: >>>> Would Time Difference of Arrival techniques combined with an array of >>>> four closely spaced antennas work with Gps signals as a means of >>>> determing the orentation of the antenna array vs the gps satellites ? >>>> (I'm thinking traditional TDOA techniques may not work with gps >>>> signals.) >>>> >>> There are commercial products available: >>> http://www.hemispheregps.com/Default.aspx?tabid=379 >>> http://www.hemispheregps.com/Default.aspx?tabid=412 >>> >>> >>> These devices claim less than 1 degree RMS heading accuracy. >>> >>> Here the antennas are integrated and a fixed 0.5 meter apart. They do >>> (or did) make a board that could be used with separate antennas, but I >>> can not find it right now. >>> >>> I have no idea of how the math works for computing heading. >>> >>> Gary >>> >> Any (almost) pair of GPS-receivers with phase measurement outputs can be >> used to make an attitude GPS receiver - sometimes called a GPS compass. >> You need decent antennas for good results. >> This is a special case of a phase ambiguity problem with moving base >> receiver and extremely short baseline. If the antennas are mounted at a >> fixed relative position, knowing the baseline gives a simpler problem. > > By having the additional antennas hooked to the same GPS core with multiple frontends, the central antenna can act like a traditional receiver. The carrier and code tracking-loops for additional antennas can then be aided by the central antenna, which will help to reduce ambiguities. After inital ambiguities have been resolved, maintaining tracking should not be too hard. > > Using multiple receivers does not give the same effect as tight integration. > >> I have read papers about using only one receiver and one antenna. The >> trick is then to use the antenna diagram and SNR from the currently >> tracked satellites to estimate an orientation. I have seen no commercial >> product trying this. Accuracy was not spectacular - a few degrees - if I >> remember correctly. Would need a very stable environment to work. A >> groundapplication (say car moving in urban environment) will influence the >> received SNRs to randomly to make a one antenna approach possible. > > Such an approach is indeed possible but fragile. You could also include shift in phase center, in which case a "bad" antenna would be good. Knowing the orientation of the antenna could allow for post-processing to compensate for phase-shift. You would loose precission from position tracking but gain an estimate in heading. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From eb4apl at cembreros.jazztel.es Sun Nov 22 00:57:48 2009 From: eb4apl at cembreros.jazztel.es (EB4APL) Date: Sun, 22 Nov 2009 01:57:48 +0100 Subject: [time-nuts] funky frequency In-Reply-To: References: <8956c301574010bcac4fdc48f8372d9a.squirrel@webmail.montana.com> <7.0.1.0.1.20091120100545.02002ac8@tapko.de> <4B06BC9E.6020103@cembreros.jazztel.es> Message-ID: <4B088C8C.8060907@cembreros.jazztel.es> Don, Send me the pin out, please. TIA Ignacio, EB4APL ....................................................................................... Don Latham wrote: > Apparently, I was goi9ng in the wrong direction... > Don > BTW, I do have a pinout for your tcxo, I think, if it is the same as the > 5.11etc. > Don > > From magnus at rubidium.dyndns.org Sun Nov 22 01:07:39 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 22 Nov 2009 02:07:39 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> <4B087ED7.7080100@rubidium.dyndns.org> Message-ID: <4B088EDB.9@rubidium.dyndns.org> Bob Camp wrote: > Hi > > If you only have one antenna and one receiver, the answer is fairly simple. Swing it around you head on the end of a long string. Plot the position reading vs time. Correlate the readings to the phase of the rotation. > > It does indeed work (it's a doppler scanner ...). You could easily argue that it's not exactly a stationary situation any more. > > Making it work correctly would involve a lot of work figuring out just how much lag the receiver has. You might have to swing it at a 10 rpm rate ... Putting it on a constantly rotating platform would work too. I actually made a comment about moving the antenna as an alternative to the use of multiple antennas. You can use the velocity vector in correlation with the local rotation indication to transform the local reference frame to that of the direction to north. Just swinging it around is pretty useless unless you bring that in correlation to that local reference frame. Also, you would like a fairly stable swingrate so that correlation becomes easier. Also, having a higher rate receiver, such as 10 or 20 Hz would also be nice. The PPS is a suitable reference pulse to correlate angle-measurements with that of the position given. Cheers, Magnus From jfor at quik.com Sun Nov 22 02:13:02 2009 From: jfor at quik.com (J. Forster) Date: Sat, 21 Nov 2009 18:13:02 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B0887C1.8090009@xtra.co.nz> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> <4B0887C1.8090009@xtra.co.nz> Message-ID: <1893.12.6.201.232.1258855982.squirrel@popacctsnew.quik.com> Not so. I'm very familiar with laying in accurate North lines for gyro testing. To get anything close to accurate (1 arc second or better) takes many hours of stellar observation with a Wild T-3 class instrument. -John =============== > Neville Michie wrote: >> >> When you think of time specifications from GPS, the GPS system is a >> poor way to find north. >> Even with a base line of 1000 metres you only have a fraction of a >> degree. >> The GPS system may be useful to get accurate time to simplify a star >> observation, from a known (GPS) >> position on this planet, but finding north is still a problem because >> of the accuracy of a small >> number of observations from a star fix. >> Gyrocompasses take some time to get a measurement >> ( one hour) but even their estimate of North cannot match the >> precision that the GPS system can get us with time. >> cheers, Neville Michie > If you are taking star shots a stellar compass can easily provide a > boresight pointing accuracy of a few arcsec. > > Bruce > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From bruce.griffiths at xtra.co.nz Sun Nov 22 03:14:01 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sun, 22 Nov 2009 16:14:01 +1300 Subject: [time-nuts] OT - GPS and North In-Reply-To: <1893.12.6.201.232.1258855982.squirrel@popacctsnew.quik.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> <4B0887C1.8090009@xtra.co.nz> <1893.12.6.201.232.1258855982.squirrel@popacctsnew.quik.com> Message-ID: <4B08AC79.10207@xtra.co.nz> When a star tracker is used as a stellar compass in effect takes simultaneous fixes on several stars and the better ones are capable of an rms error of a few arc seconds, largely limited by atmospheric instability. These are usually used for determining space vehicle attitude, in which case the instability due to seeing is much smaller than when immersed in the atmosphere. They have been used as relatively inexpensive position encoders for pointing a telescope to within a few arc seconds. Pattern recognition techniques are used to identify stars in a relatively wide field (a few degrees) slightly defocused image (improves centroiding accuracy). Star tracker for Clementine mission: http://www.osti.gov/bridge/servlets/purl/86977-ULkJcR/webviewable/86977.pdf A more accurate version: http://www.newworldt.com/download/DTU/microASC%20Summary.pdf telescope pointing application: http://www.ifa.hawaii.edu/faculty/pickles/AJP/spie3351.07.pdf http://www.ifa.hawaii.edu/users/pickles/AJP/AMOS2003_v4.pdf Measuring the position (altitude + azimuth) of one star at a time using a theodolite is not the most efficient method of determining the direction of the meridian. Its far better to measure the position of several stars at once as in the stellar compass, however a longer focal length camera lens than usually used in a star tracker is desrable for increased accuracy. Bruce J. Forster wrote: > Not so. I'm very familiar with laying in accurate North lines for gyro > testing. To get anything close to accurate (1 arc second or better) takes > many hours of stellar observation with a Wild T-3 class instrument. > > -John > > =============== > > > > >> Neville Michie wrote: >> >>> When you think of time specifications from GPS, the GPS system is a >>> poor way to find north. >>> Even with a base line of 1000 metres you only have a fraction of a >>> degree. >>> The GPS system may be useful to get accurate time to simplify a star >>> observation, from a known (GPS) >>> position on this planet, but finding north is still a problem because >>> of the accuracy of a small >>> number of observations from a star fix. >>> Gyrocompasses take some time to get a measurement >>> ( one hour) but even their estimate of North cannot match the >>> precision that the GPS system can get us with time. >>> cheers, Neville Michie >>> >> If you are taking star shots a stellar compass can easily provide a >> boresight pointing accuracy of a few arcsec. >> >> Bruce >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From namichie at gmail.com Sun Nov 22 03:52:45 2009 From: namichie at gmail.com (Neville Michie) Date: Sun, 22 Nov 2009 14:52:45 +1100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <1893.12.6.201.232.1258855982.squirrel@popacctsnew.quik.com> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> <4B0887C1.8090009@xtra.co.nz> <1893.12.6.201.232.1258855982.squirrel@popacctsnew.quik.com> Message-ID: <1F71AB50-EFA5-4CD2-9583-4518FD2177E8@gmail.com> I once went through the exercise of finding North from a station at home. A gps fix would give me +- - 1metre northing and + - 1 metre easting, another fix 1000m away would be the same, a lousy base for an accurate azimuth. Using an ephemeris for constants, a theodolite fix on a circumpolar star taken at 6 hour intervals starts to get a value with the limits being the usual limits of observing stars but less the refraction errors. I recorded the data with respect to a Referred Object, ( a street light 4 km away) Several times I repeated this exercise ( on other nights) and I was disssapointed by the precision. Now my theodolite is a Wild T1, and the method does not lend itself to getting the maximum precision from the instrument, but I was deeply impressed by the difficulty of getting an accurate measure of true North. cheers, Neville Michie On 22/11/2009, at 1:13 PM, J. Forster wrote: > Not so. I'm very familiar with laying in accurate North lines for gyro > testing. To get anything close to accurate (1 arc second or better) > takes > many hours of stellar observation with a Wild T-3 class instrument. > > -John > > =============== > > > >> Neville Michie wrote: >>> >>> When you think of time specifications from GPS, the GPS system is a >>> poor way to find north. >>> Even with a base line of 1000 metres you only have a fraction of a >>> degree. >>> The GPS system may be useful to get accurate time to simplify a star >>> observation, from a known (GPS) >>> position on this planet, but finding north is still a problem >>> because >>> of the accuracy of a small >>> number of observations from a star fix. >>> Gyrocompasses take some time to get a measurement >>> ( one hour) but even their estimate of North cannot match the >>> precision that the GPS system can get us with time. >>> cheers, Neville Michie >> If you are taking star shots a stellar compass can easily provide a >> boresight pointing accuracy of a few arcsec. >> >> Bruce >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ > time-nuts > and follow the instructions there. From SAIDJACK at aol.com Sun Nov 22 04:03:07 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sat, 21 Nov 2009 23:03:07 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: Hi Bjoern, I respectfully disagree. I measured the loss through the GPS amp and Mini Circuits splitter at only 10.1dB. That's really not a lot. I couldn't find a loss-spec in the Thunderbolts' specification. The Agilent amp has GPS filters in it that improve signal quality by filtering out all non-GPS signals. Someone else had the same problem here (that's how the discussion initially started) thinking his Symmetricom splitter was dead. I think it's safe to say a GPSDO can be expected to work with a name-brand GPS splitter (which it did not either for the other gentleman). So if the M12+, M12M, and all other GPS receivers I have can all handle this signal without a hitch, except the Thunderbolt, then this means the Thunderbolt requires special attention (or in my case possibly it's own GPS antenna). I will try to change the AMU settings as Warren suggested, that makes sense. Maybe this is what we should have tried from the beginning to make our Thunderbolts work? bye, Said In a message dated 11/21/2009 14:18:51 Pacific Standard Time, bg at lysator.liu.se writes: Hi Said, As we talked about some weeks ago... your test is unfair to the Tbolt, but that is perhaps intentional. The Tbolt will need more gain to work. You are giving it a signal that is out of spec. -- Bj?rn From jltran at worldnet.att.net Sun Nov 22 04:20:37 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Sat, 21 Nov 2009 22:20:37 -0600 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: Message-ID: I think I was the one that started this. My problem was the Tbolt did not work when connected to the Symmetricom splitter alone (except for the antenna of course) but worked great when the splitter was also connected to a Z3816A. I think it must have to do with lack of appropriate power from the Tbolt to power the splitter though I have not taken any detailed measurements. If anyone wants a particular measurement, let me know. I contacted Symmetricom to try to get a schematic of the splitter without any luck. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of SAIDJACK at aol.com Sent: Saturday, November 21, 2009 10:03 PM To: time-nuts at febo.com Subject: Re: [time-nuts] Thunderbolt reception problems Hi Bjoern, I respectfully disagree. I measured the loss through the GPS amp and Mini Circuits splitter at only 10.1dB. That's really not a lot. I couldn't find a loss-spec in the Thunderbolts' specification. The Agilent amp has GPS filters in it that improve signal quality by filtering out all non-GPS signals. Someone else had the same problem here (that's how the discussion initially started) thinking his Symmetricom splitter was dead. I think it's safe to say a GPSDO can be expected to work with a name-brand GPS splitter (which it did not either for the other gentleman). From bg at lysator.liu.se Sun Nov 22 04:57:10 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 22 Nov 2009 05:57:10 +0100 (CET) Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: Message-ID: <62133.87.227.52.225.1258865830.squirrel@webmail.lysator.liu.se> Hi Said, With your background, I assumed you would know better... What is your antenna gain? What is your antenna cable loss? Does the Tbolt work correctly connected directly to the GPS antenna? Do you have an inline LNA to add close to the antenna? Do you have a higher gain antenna available? If 10dB is a lot or nost... that DO depend on the circumstances. -- Bj?rn > Hi Bjoern, > > I respectfully disagree. I measured the loss through the GPS amp and Mini > Circuits splitter at only 10.1dB. That's really not a lot. I couldn't > find > a loss-spec in the Thunderbolts' specification. > > The Agilent amp has GPS filters in it that improve signal quality by > filtering out all non-GPS signals. > > Someone else had the same problem here (that's how the discussion > initially started) thinking his Symmetricom splitter was dead. I think > it's safe to > say a GPSDO can be expected to work with a name-brand GPS splitter (which > it did not either for the other gentleman). > > So if the M12+, M12M, and all other GPS receivers I have can all handle > this signal without a hitch, except the Thunderbolt, then this means the > Thunderbolt requires special attention (or in my case possibly it's own > GPS > antenna). > > I will try to change the AMU settings as Warren suggested, that makes > sense. Maybe this is what we should have tried from the beginning to make > our > Thunderbolts work? > > bye, > Said > > > In a message dated 11/21/2009 14:18:51 Pacific Standard Time, > bg at lysator.liu.se writes: > > Hi Said, > > As we talked about some weeks ago... your test is unfair to the Tbolt, > but > that is perhaps intentional. The Tbolt will need more gain to work. You > are giving it a signal that is out of spec. > > -- > > Bj?rn > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From usenet at teply.info Sun Nov 22 07:50:16 2009 From: usenet at teply.info (Florian Teply) Date: Sun, 22 Nov 2009 08:50:16 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> Message-ID: <200911220850.16642.usenet@teply.info> Am Saturday 21 November 2009 20:32:11 schrieb J. Forster: > OK. Sme GPS receivers have magnetic sensors. What do they do with/about > magnetic deviation. > Just a wild guess: The GPS receiver also knows its location, and magnetic deviation is known to some degree in its variation over earth's surface. So, why not introduce a map of magnetic deviation that basically tells you: at location Lat; Long, your magnetic north points at 357 degrees instead of 360. Bingo, you're done. That would be especially useful in the pole region, where deviation becomes large, as the accuracy of magnetic sensors probably is in the order of a couple degrees. Sounds reasonable, doesn't it? HTH, Florian From bg at lysator.liu.se Sun Nov 22 09:43:33 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 22 Nov 2009 10:43:33 +0100 (CET) Subject: [time-nuts] OT - GPS and North In-Reply-To: <200911220850.16642.usenet@teply.info> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <200911220850.16642.usenet@teply.info> Message-ID: <63266.87.227.52.225.1258883013.squirrel@webmail.lysator.liu.se> Hi Florian, That is basicly the way it is done. The "source" is a magnetic model - a "formula" with lots of coefficients, you input your position and the output is an approximation of your magnetic declination at that position. It can be implemented by precomputing a lockup table (map) with the required bin size, or store coefficients and do the calculation in the receiver. This is actually an exact analogy with the computation of Mean Sea Level height. The GPS receiver can only measure ellipsoid height, but many receivers will output a MSL heigt, by computing or search in a precomputed "geoid separation"-map. -- Bj?rn > Am Saturday 21 November 2009 20:32:11 schrieb J. Forster: >> OK. Sme GPS receivers have magnetic sensors. What do they do with/about >> magnetic deviation. >> > Just a wild guess: The GPS receiver also knows its location, and magnetic > deviation is known to some degree in its variation over earth's surface. > So, > why not introduce a map of magnetic deviation that basically tells you: at > location Lat; Long, your magnetic north points at 357 degrees instead of > 360. > Bingo, you're done. That would be especially useful in the pole region, > where > deviation becomes large, as the accuracy of magnetic sensors probably is > in > the order of a couple degrees. > > Sounds reasonable, doesn't it? > > HTH, > Florian > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From magnus at rubidium.dyndns.org Sun Nov 22 15:05:26 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 22 Nov 2009 16:05:26 +0100 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: <62133.87.227.52.225.1258865830.squirrel@webmail.lysator.liu.se> References: <62133.87.227.52.225.1258865830.squirrel@webmail.lysator.liu.se> Message-ID: <4B095336.90403@rubidium.dyndns.org> bg at lysator.liu.se wrote: > Hi Said, > > With your background, I assumed you would know better... > > What is your antenna gain? What is your antenna cable loss? Does the Tbolt > work correctly connected directly to the GPS antenna? Do you have an > inline LNA to add close to the antenna? Do you have a higher gain antenna > available? > > If 10dB is a lot or nost... that DO depend on the circumstances. If you already moved the signal towards the lower end of the input sensitivity range, then adding additional loss is an issue. GPS receivers degrade their performance gracefully with lower input signal to the point where it degrades more and more ungracefully. It's one of the tests that one should do. I have come to realize that my rig suffers severly from cable-loss and the lack of antenna gain to be followed by a passive splitter before it hits an active splitter. I had to build a gain-rig to overcome part of that, but it doesn't feel right to use two LNAs in series. It's just darkness before my eyes but it works. The first fix to this is an inline amplifier to be inserted at the antenna. Another fix would be to use a better antenna cable. Cheers, Magnus From stanley_reynolds at yahoo.com Sun Nov 22 16:28:07 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Sun, 22 Nov 2009 08:28:07 -0800 (PST) Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: <4B095336.90403@rubidium.dyndns.org> References: <62133.87.227.52.225.1258865830.squirrel@webmail.lysator.liu.se> <4B095336.90403@rubidium.dyndns.org> Message-ID: <120742.29114.qm@web30306.mail.mud.yahoo.com> Using two Bullet II, Trimble p/n 4155600, antennas with all my receivers for now. They feed two cheap TV satellite splitters 4 receiver ports each, DC power diode steered to the antenna port from each receiver port. Feed line is RG6 50 to 75 feet in length. Never had less than one less than the max number of sats being tracked most of the time at the max. Receiver list: 3 thunderbolts, Lucent cell site GPSDO with resistor to load antenna detecting circuit, 2 Trak System 8820 type station clock GPSDO one with 8 channel one with?6 channel receiver. In the past have used other receivers like Zyfer with no problems. Stanley From stanley_reynolds at yahoo.com Sun Nov 22 16:44:33 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Sun, 22 Nov 2009 08:44:33 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <200911220850.16642.usenet@teply.info> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <200911220850.16642.usenet@teply.info> Message-ID: <767640.15199.qm@web30305.mail.mud.yahoo.com> Notice several of the eloran/GPS receivers advertise better than one degree heading accuracy even when stationary. Wonder if this the result of the sensor using an array of ferrite bar antennas or just a magnetic compass ? "The eLoran Heading output using Loran-C provides bearing accuracy better than 1?, making the e-LORAN a practical alternative to more expensive heading devices" http://www.si-tex.com/2009description_e-loran.htm http://www.crossrate.com/elgps1110 Stanley From had at to-way.com Sun Nov 22 17:26:47 2009 From: had at to-way.com (Had) Date: Sun, 22 Nov 2009 09:26:47 -0800 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: <120742.29114.qm@web30306.mail.mud.yahoo.com> References: <62133.87.227.52.225.1258865830.squirrel@webmail.lysator.liu.se> <4B095336.90403@rubidium.dyndns.org> <120742.29114.qm@web30306.mail.mud.yahoo.com> Message-ID: The drawing below shows this weeks multipal GPS receiver hook up. I have no problems with the T-Bolt's or any other receiver. Minimum Sats locked up 5, maximum 11. Had, K7MLR >[] A fine is a tax for doing wrong. A tax is a fine for doing well. Peter Cooper, of Fermi Lab, says, "Every experimentalist knows that the apparatus, or at least your understanding of it, is always at fault until demonstrated otherwise." He also says, "Nature is really unmoved by what I, or anyone else, believes." -------------- next part -------------- A non-text attachment was scrubbed... Name: GPS Hook Up.jpg Type: image/jpeg Size: 77687 bytes Desc: not available URL: From magnus at rubidium.dyndns.org Sun Nov 22 17:18:58 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 22 Nov 2009 18:18:58 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <767640.15199.qm@web30305.mail.mud.yahoo.com> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <200911220850.16642.usenet@teply.info> <767640.15199.qm@web30305.mail.mud.yahoo.com> Message-ID: <4B097282.3070606@rubidium.dyndns.org> Stanley Reynolds wrote: > Notice several of the eloran/GPS receivers advertise better than one degree heading accuracy even when stationary. Wonder if this the result of the sensor using an array of ferrite bar antennas or just a magnetic compass ? > > "The eLoran Heading output using Loran-C provides bearing accuracy better than 1?, making the e-LORAN a practical alternative to more expensive heading devices" > http://www.si-tex.com/2009description_e-loran.htm As expected: Antenna Type Active dual-loop eLoran H-field antenna with GPS patch antenna dual-loop H-field Loran antenna is expected. H-field antennas has a zero in the plane of the loop. To compensate another antenna is mounted with 90 degrees difference. Now, this allows the use of the signal from both antennas to measure the heading towards each of the LORAN stations, which together with the position can be converted to heading towards North. If the GPS receiver had two antennas with similar directional characteristics, it would too be able to do similar tricks. Cheers, Magnus From stanley_reynolds at yahoo.com Sun Nov 22 19:33:07 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Sun, 22 Nov 2009 11:33:07 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B097282.3070606@rubidium.dyndns.org> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <200911220850.16642.usenet@teply.info> <767640.15199.qm@web30305.mail.mud.yahoo.com> <4B097282.3070606@rubidium.dyndns.org> Message-ID: <523485.8862.qm@web30301.mail.mud.yahoo.com> Yes, found this patent : http://www.freepatentsonline.com/y2008/0186232.html "A method and radio navigation system compass apparatus for determining true north or azimuth or orientation of a vehicle or the like by the use of integrated Loran and satellite radio navigation receivers employing crossed-loop H-field antennas for the Loran reception, or the use of at least three Loran type transmitter, or two Loran type transmitter and a synchronized clock for determining both position and azimuth. " synergy, the whole is greater than the sum of the individual parts Both GPS and loran depend on the phase/frequency/time accuracy of their source, but I wonder if other signals not as accurate but maybe short-term stable could be used to improve combined stability such as TV and radio transmitters. With such a large source of possible transmitters comparison of them to GPS and loran to pick a few good ones to add both hold-over from gps and or loran loss. For example a CDMA cell site that is dependent on GPS would slowly deteriorate if GPS was lost, but a large number of CDMA cell sites would continue to work if they could be synced to another source. Besides the hold over capability I would be interested in ways to combine as many independent sources to improve accuracy?like the use of more accurate frequency sources to improve GPS accuracy: http://plan.geomatics.ucalgary.ca/papers/ENC06_Paper74_WatsonetAl_v3Web.pdf Or maybe a time-nut antidote would be better ;-) Stanley ----- Original Message ---- From: Magnus Danielson magnus at rubidium.dyndns.org To: Discussion of precise time and frequency measurement Sent: Sun, November 22, 2009 11:18:58 AM Subject: Re: [time-nuts] OT - GPS and North Stanley Reynolds wrote: > Notice several of the eloran/GPS receivers advertise better than one degree heading accuracy even when stationary. Wonder if this the result of the sensor using an array of ferrite bar antennas or just a magnetic compass ? > > "The eLoran Heading output using Loran-C provides bearing accuracy better than 1?, making the e-LORAN a practical alternative to more expensive heading devices" > http://www.si-tex.com/2009description_e-loran.htm As expected: Antenna Type Active dual-loop eLoran H-field antenna with GPS patch antenna dual-loop H-field Loran antenna is expected. H-field antennas has a zero in the plane of the loop. To compensate another antenna is mounted with 90 degrees difference. Now, this allows the use of the signal from both antennas to measure the heading towards each of the LORAN stations, which together with the position can be converted to heading towards North. If the GPS receiver had two antennas with similar directional characteristics, it would too be able to do similar tricks. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From SAIDJACK at aol.com Sun Nov 22 19:44:56 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sun, 22 Nov 2009 14:44:56 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: Hi Guys, changing the AMU thresholds to 2.0 as suggested by Warren fixed the problem, the unit is now working properly, thanks much for the hint. And no, this was not obvious to me. It is always great to get constructive help rather than the "you should know better" type of comments. In the end, it looks like this turned out to be a configuration issue rather than a receiver sensitivity issue. But this also begs the question: how much performance degradation will I get when using 2.0 as the AMU threshold rather than the factory default. There must have been a reason why Trimble set the default so high, they mention something about multipath rejection in the manual. Why do I want to get this unit up and running: this unit has been tested to have very good phase noise performance. I'll use anyone's low noise source anyday. bye, Said In a message dated 11/22/2009 07:06:00 Pacific Standard Time, mag nus at rubidium.dyndns.org writes: If you already moved the signal towards the lower end of the input sensitivity range, then adding additional loss is an issue. GPS receivers degrade their performance gracefully with lower input signal to the point where it degrades more and more ungracefully. It's one of the tests that one should do. I have come to realize that my rig suffers severly from cable-loss and the lack of antenna gain to be followed by a passive splitter before it hits an active splitter. I had to build a gain-rig to overcome part of that, but it doesn't feel right to use two LNAs in series. It's just darkness before my eyes but it works. The first fix to this is an inline amplifier to be inserted at the antenna. Another fix would be to use a better antenna cable. Cheers, Magnus From GandalfG8 at aol.com Sun Nov 22 20:13:21 2009 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Sun, 22 Nov 2009 15:13:21 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: In a message dated 22/11/2009 19:45:35 GMT Standard Time, SAIDJACK at aol.com writes: changing the AMU thresholds to 2.0 as suggested by Warren fixed the problem, the unit is now working properly, thanks much for the hint. And no, this was not obvious to me. Hi Said Just out of interest, what levels of AMU are you seeing reported? According to Trimble's Thunderbolt Monitor version 2.6 the six satellites I'm tracking right now are showing AMU values of over 40 and another stops tracking when its AMU drops to approx 33 but starts tracking again at a reported AMU of approx 36 to 37. My signal level mask is set to 4.0, and I don't seem to have had any problems because of that, but I'm intrigued as to the actual relationship between the quantity described as the signal level mask and the reported AMU levels. I would have assumed the units to be the same but that doesn't seem to be the case. OK, so I've just dropped the threshold to 2.0 and am now tracking eight satellites, with the reported levels for the one mentioned above still varying as before and another just below 30 with neither dropping out, but I'm still non the wiser as to the actual value of the set threshold in terms of the reported AMU levels. regards Nigel GM8PZR From iovane at inwind.it Sun Nov 22 21:08:06 2009 From: iovane at inwind.it (iovane at inwind.it) Date: Sun, 22 Nov 2009 22:08:06 +0100 Subject: [time-nuts] OT - GPS and North Message-ID: Thanks all. The conclusion seems to be that an ordinary and stationary GPS receiver with a single omnidiretional antenna knows very well where satellites are relative to the true North, and where the true North is relative to satellites, but doesn't know (more precisely: can't indicate, as it lacks another reference) where satellites or the North actually are. Eventually this appears quite obvious. Antonio I8IOV From bg at lysator.liu.se Sun Nov 22 21:22:03 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Sun, 22 Nov 2009 22:22:03 +0100 (CET) Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: Message-ID: <54363.87.227.52.225.1258924923.squirrel@webmail.lysator.liu.se> Hi Nigel, AMU and SNR are two different scales. I do not have a translation. A Kepler award recepient once explained Trimbles AMU as "a meaningless unit". That said, SNR or C/N0 values cannot be directly compared between different receivers since the measures might be taken at different points in the receiver. The Trimble monitor program can be made to switch between AMU and SNR in one of the configuration menues. I think you might have switched to SNR. With above uncertanty of specific SNR definitions noted, most receivers are enjoying an excellent signal if the highest elevation receivers have a SNR above 50. If the highest SVs get +45dB that is still decent. -- Bj?rn > > In a message dated 22/11/2009 19:45:35 GMT Standard Time, SAIDJACK at aol.com > writes: > > changing the AMU thresholds to 2.0 as suggested by Warren fixed the > problem, the unit is now working properly, thanks much for the hint. And > no, this > was not obvious to me. > > > Hi Said > > Just out of interest, what levels of AMU are you seeing reported? > > According to Trimble's Thunderbolt Monitor version 2.6 the six satellites > I'm tracking right now are showing AMU values of over 40 and another stops > tracking when its AMU drops to approx 33 but starts tracking again at a > reported AMU of approx 36 to 37. > > My signal level mask is set to 4.0, and I don't seem to have had any > problems because of that, but I'm intrigued as to the actual relationship > between the quantity described as the signal level mask and the reported > AMU > levels. > I would have assumed the units to be the same but that doesn't seem to be > the case. > > OK, so I've just dropped the threshold to 2.0 and am now tracking eight > satellites, with the reported levels for the one mentioned above still > varying > as before and another just below 30 with neither dropping out, but I'm > still non the wiser as to the actual value of the set threshold in terms > of > the reported AMU levels. > > regards > > Nigel > GM8PZR > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From bruce.griffiths at xtra.co.nz Sun Nov 22 21:23:43 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 23 Nov 2009 10:23:43 +1300 Subject: [time-nuts] OT - GPS and North In-Reply-To: References: Message-ID: <4B09ABDF.4050909@xtra.co.nz> iovane at inwind.it wrote: > Thanks all. > > The conclusion seems to be that an ordinary and stationary GPS receiver with a single > omnidiretional antenna knows very well where satellites are relative to the true North, > and where the true North is relative to satellites, but doesn't know (more precisely: > can't indicate, as it lacks another reference) where satellites or the North actually are. > Eventually this appears quite obvious. > > Antonio I8IOV > > > You could (temporarily) install a structure that blocks reception in one direction and then infer the meridian direction from the occultation of SVs by the obstruction. However the accuracy of the determination wont be high. Bruce From iovane at inwind.it Sun Nov 22 21:32:34 2009 From: iovane at inwind.it (iovane at inwind.it) Date: Sun, 22 Nov 2009 22:32:34 +0100 Subject: [time-nuts] OT - GPS and North Message-ID: > iovane at inwind.it wrote: > > Thanks all. > > > > The conclusion seems to be that an ordinary and stationary GPS receiver with a single > > omnidiretional antenna knows very well where satellites are relative to the true North, > > and where the true North is relative to satellites, but doesn't know (more precisely: > > can't indicate, as it lacks another reference) where satellites or the North actually are. > > Eventually this appears quite obvious. > > > > Antonio I8IOV > > > > > > > You could (temporarily) install a structure that blocks reception in one > direction and then infer the meridian direction from the occultation of > SVs by the obstruction. > However the accuracy of the determination wont be high. > > Bruce Anyway, that's an idea. Antonio From hmurray at megapathdsl.net Sun Nov 22 21:36:27 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sun, 22 Nov 2009 13:36:27 -0800 Subject: [time-nuts] OT - GPS and North In-Reply-To: Message from Stanley Reynolds of "Sun, 22 Nov 2009 11:33:07 PST." <523485.8862.qm@web30301.mail.mud.yahoo.com> Message-ID: <20091122213628.4071DBCFC@ip-64-139-1-69.sjc.megapath.net> stanley_reynolds at yahoo.com said: > For example a CDMA cell site that is dependent on GPS would slowly > deteriorate if GPS was lost, but a large number of CDMA cell sites > would continue to work if they could be synced to another source. Unless, of course, that other source was depending on GPS and has the same problem you are having. -- These are my opinions, not necessarily my employer's. I hate spam. From warrensjmail-one at yahoo.com Sun Nov 22 21:46:57 2009 From: warrensjmail-one at yahoo.com (WarrenS) Date: Sun, 22 Nov 2009 13:46:57 -0800 Subject: [time-nuts] Thunderbolt reception problems Message-ID: <902041496E8D42319C6100AB4167E5F7@WSOffice> Said >changing the AMU thresholds to 2.0 fixed the problem, If 3 was not working, you should be able to go lower than 2, likely 1.0 to 1.5 will be better yet. The way I tell is using Lady Heather, if there are satellites signals with levels between 20 and 30 dBc with good ACCUs that are still not being used, I lower the AMU value using Tboltmon.exe. > how much performance degradation will I get when using 2.0 as the AMU threshold rather than the factory default. Here is what I have found, concerning that question. Lowering the AMU will likely improve the noise performance of the typical setup, for some less than oblivious reasons concerning how the Tbolt reacts in holdover mode and when satellites are switched in and out due to their signal level. Much better to use a weak signal than have no signal AND also better not to toggle a satellite in and out that is on the threshold, Better to lower the AMU threshold and rise the elevation mask. Concerning the relation of AMU to dBc, what I've seen is: AMU of 4 is in the high 30, AMU of 3 is in the mid 30, AMU of 2 is in the high 20, AMU of 1 is in the mid 20, A good outdoor antenna will give dBc in the high 40 to 50s and poor indoor antena will give dBc in the mid 30's AND still works fine, and anything above 25 dBc works OK when in the fixed position 'Overdetermined Clock' mode. To the different question of how much will the performance be degraded using a weak antenna signal, Again the not so oblivious answer is typically only a little, and may even help in some cases. Weak signals need the TC to be set higher than the default 100 sec, OR performance will be degraded. The added signal noise needs to be averaged over a longer time period. My experience is that using a standard 'car' antenna indoors, with a properly set TC, Damping and Dac_Gain will out perform a unit on a good view outdoor antenna IF that Tbolt is still set to the default settings, which most seem to be. The difference I see when Both are set up correct is around 25%. The bottom line is that a good signal AND an accurate location, IS required to get the VERY BEST performance from a Tbolt, BUT there are MANY other things that have MUCH more effect that are often overlooked. ws ********** Hi Guys, changing the AMU thresholds to 2.0 as suggested by Warren fixed the problem, the unit is now working properly, thanks much for the hint. And no, this was not obvious to me. It is always great to get constructive help rather than the "you should know better" type of comments. In the end, it looks like this turned out to be a configuration issue rather than a receiver sensitivity issue. But this also begs the question: how much performance degradation will I get when using 2.0 as the AMU threshold rather than the factory default. There must have been a reason why Trimble set the default so high, they mention something about multipath rejection in the manual. Why do I want to get this unit up and running: this unit has been tested to have very good phase noise performance. I'll use anyone's low noise source anyday. bye, Said From magnus at rubidium.dyndns.org Sun Nov 22 21:54:03 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 22 Nov 2009 22:54:03 +0100 Subject: [time-nuts] OT - GPS and North In-Reply-To: <523485.8862.qm@web30301.mail.mud.yahoo.com> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <200911220850.16642.usenet@teply.info> <767640.15199.qm@web30305.mail.mud.yahoo.com> <4B097282.3070606@rubidium.dyndns.org> <523485.8862.qm@web30301.mail.mud.yahoo.com> Message-ID: <4B09B2FB.9060104@rubidium.dyndns.org> Stanley Reynolds wrote: > Yes, found this patent : > > http://www.freepatentsonline.com/y2008/0186232.html > > "A method and radio navigation system compass apparatus for determining true north or azimuth or orientation of a vehicle or the like by the use of integrated Loran and satellite radio navigation receivers employing crossed-loop H-field antennas for the Loran reception, or the use of at least three Loran type transmitter, or two Loran type transmitter and a synchronized clock for determining both position and azimuth. " > > > synergy, the whole is greater than the sum of the individual parts Traditional Directional Finding techniquest combined with positional information from the Loran-C is a good mix. Question is if the invention is that big that a good patent would hold. > Both GPS and loran depend on the phase/frequency/time accuracy of their source, but I wonder if other signals not as accurate but maybe short-term stable could be used to improve combined stability such as TV and radio transmitters. With such a large source of possible transmitters comparison of them to GPS and loran to pick a few good ones to add both hold-over from gps and or loran loss. For example a CDMA cell site that is dependent on GPS would slowly deteriorate if GPS was lost, but a large number of CDMA cell sites would continue to work if they could be synced to another source. You can use either the timing or direction or both from many different sources in combination with that of a number of different satellite systems in a combined pseudo-range and orientation input for a position and heading analysis. You can weigth in timing from several VLF sources in combination with the pseudo-ranges of the sats. The problem with VLF sources is the shift in delay due to shift in atmosphere, so their contribution would be limited unless fairly nearby. > Besides the hold over capability I would be interested in ways to combine as many independent sources to improve accuracy like the use of more accurate frequency sources to improve GPS accuracy: > http://plan.geomatics.ucalgary.ca/papers/ENC06_Paper74_WatsonetAl_v3Web.pdf > > > Or maybe a time-nut antidote would be better ;-) Maybe. :) Cheers, Magnus From jfor at quik.com Sun Nov 22 21:56:24 2009 From: jfor at quik.com (J. Forster) Date: Sun, 22 Nov 2009 13:56:24 -0800 (PST) Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B09B2FB.9060104@rubidium.dyndns.org> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> <4B08324F.4070302@rubidium.dyndns.org> <1924.12.6.201.171.1258831931.squirrel@popacctsnew.quik.com> <200911220850.16642.usenet@teply.info> <767640.15199.qm@web30305.mail.mud.yahoo.com> <4B097282.3070606@rubidium.dyndns.org> <523485.8862.qm@web30301.mail.mud.yahoo.com> <4B09B2FB.9060104@rubidium.dyndns.org> Message-ID: <1932.12.6.201.37.1258926984.squirrel@popacctsnew.quik.com> It's going to be hard to use LORAN C, if the system is shut down. -John ================= > Stanley Reynolds wrote: >> Yes, found this patent : >> >> http://www.freepatentsonline.com/y2008/0186232.html >> >> "A method and radio navigation system compass apparatus for determining >> true north or azimuth or orientation of a vehicle or the like by the use >> of integrated Loran and satellite radio navigation receivers employing >> crossed-loop H-field antennas for the Loran reception, or the use of at >> least three Loran type transmitter, or two Loran type transmitter and a >> synchronized clock for determining both position and azimuth. " >> >> >> synergy, the whole is greater than the sum of the individual parts > > Traditional Directional Finding techniquest combined with positional > information from the Loran-C is a good mix. Question is if the invention > is that big that a good patent would hold. [snip] From stanley_reynolds at yahoo.com Sun Nov 22 22:11:17 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Sun, 22 Nov 2009 14:11:17 -0800 (PST) Subject: [time-nuts] backup to GPS after jan 2010, was: OT - GPS and North In-Reply-To: <20091122213628.4071DBCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091122213628.4071DBCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <433094.88033.qm@web30301.mail.mud.yahoo.com> Yes if the GPS outage is wide spread would need to eliminate the sources in the same situation. Guess another common view atomic clock would be needed. Some of the cesium clocks were used to provide wire-line timing, don't know if these would be still available and how to distribute this accuracy. Think some but not all cell sites would have wire-line connections, just don't know if this is useful. Stanley ----- Original Message ---- From: Hal Murray To: Discussion of precise time and frequency measurement Sent: Sun, November 22, 2009 3:36:27 PM Subject: Re: [time-nuts] OT - GPS and North stanley_reynolds at yahoo.com said: > For example a CDMA cell site that is dependent on GPS would slowly > deteriorate if GPS was lost, but a large number of CDMA cell sites > would continue to work if they could be synced to another source. Unless, of course, that other source was depending on GPS and has the same problem you are having. -- These are my opinions, not necessarily my employer's.? I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From geraldo at decampos.net Sun Nov 22 22:21:02 2009 From: geraldo at decampos.net (Geraldo Lino de Campos) Date: Sun, 22 Nov 2009 20:21:02 -0200 Subject: [time-nuts] Thunderbolt reception problems Message-ID: I am using a Tbolt with a Symmetricom 58432A antenna, half sky view, and a HP 58515A distribution amplifier without any problems, using the default parameters. ------------------------------------ Geraldo Lino de Campos geraldo at decampos.net From hmurray at megapathdsl.net Sun Nov 22 22:39:56 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sun, 22 Nov 2009 14:39:56 -0800 Subject: [time-nuts] Alternate frequency sources - second opinions Message-ID: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> Hockey puck (or mouse) type GPS receivers are available for under $100. What can I get in that price range that doesn't depend on GPS? I'm interested in millisecond accuracy as well as nanosecond. Has anybody built a WWVB-DO? (Time to dust off my WWVB toys.) Is there some good WWV setup? Somebody mentioned TV and radio stations recently. (I think it was part of the North discussion.) What sort of frequency source is at the root of the local TV or radio stations? Is the sync timing for TV stations derived from the same source as the carrier? Or are there two separate clocks to discuss? How about the color-burst frequency? What do radio/TV stations do for backups? If there was a hurricane or earthquake that broke the main transmitter are they likely to switch to a backup with a different timing source? -- These are my opinions, not necessarily my employer's. I hate spam. From stanley_reynolds at yahoo.com Sun Nov 22 22:49:32 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Sun, 22 Nov 2009 14:49:32 -0800 (PST) Subject: [time-nuts] backup to GPS after jan 2010, was: OT - GPS and North In-Reply-To: <433094.88033.qm@web30301.mail.mud.yahoo.com> References: <20091122213628.4071DBCFC@ip-64-139-1-69.sjc.megapath.net> <433094.88033.qm@web30301.mail.mud.yahoo.com> Message-ID: <42030.25546.qm@web30308.mail.mud.yahoo.com> Further if at least one cell site has a accurate clock how far could it be repeated before it lost it's useful accuracy using the CDMA signal as in : http://www.endruntechnologies.com/frequency-standard-rackmount.htm As cdma is not available everywhere: http://www.endruntechnologies.com/gps-cdma2.htm Would assume if you wanted to distribute accurate timing then if not GPS, CDMA, or VLF then some radio signal hopeful for cell sites some method you are allowed to use. They already have control links between sites so it would be the natural choice to distribute this timing info. Stanley From magnus at rubidium.dyndns.org Sun Nov 22 22:50:58 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sun, 22 Nov 2009 23:50:58 +0100 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: Message-ID: <4B09C052.3070002@rubidium.dyndns.org> Dear Said, SAIDJACK at aol.com wrote: > Hi Guys, > > changing the AMU thresholds to 2.0 as suggested by Warren fixed the > problem, the unit is now working properly, thanks much for the hint. And no, this > was not obvious to me. > > It is always great to get constructive help rather than the "you should > know better" type of comments. I certainly understand that one. > In the end, it looks like this turned out to be a configuration issue > rather than a receiver sensitivity issue. But this also begs the question: how > much performance degradation will I get when using 2.0 as the AMU threshold > rather than the factory default. There must have been a reason why Trimble > set the default so high, they mention something about multipath rejection > in the manual. I kindly disagree... sorry for the long rambling motivation. While I have not been able to conclude exactly what the AMU measure really is (Amplitude Measurement Unit), but it is similar at least to C/N measures. When the receiver has a bad C/N measure from a certain source, it may be wise not to rely on it. The signal level from each sat can be configured to be delivered in either AMU or in dB-Hz where the later allows comparision among other GPSes. The best description of AMU I have is from the Lassen iQ manual where it states: Note ? The signal level provided in this packet is a linear measurement of the signal strength after correlation or de-spreading. Units, either AMU or dBHz, are controlled by Packet 0x35. Thus, you can request the 20*log10(AMU)+Const that converts it into dB/sqrt(Hz) measure. The Lassen iQ AMU limit is default at 2 and for extended sensitivity 1.2. The Thunderbolt AMU values may not need to have the same relationship to dB/sqrt(Hz) as the Lassen iQ, but there may be more to it. The Lassen iQ is tailored towards navigation gear (hence the garage startup) where as the Thunderbolt is aimed at timing. Regardless, AMU or C/N measures is an indication of correlation strength and thus a measure of signal quality. It should rightfully contribute to the TDOP measure. The AMU limit is a pre-T-RAIM cleanup protection value. If you needed to lower your AMU limit from 4 to 2, you are feeding the Thunderbolt a signal level below the intended levels. A 6 dB raise and you would not have needed to shift the limit for the same tracking result. Regardless of where the limit is, the lower AMU values will indicate a higher noise level and thus higher uncertainty in time than otherwise obtained. So, the 10 dB loss in the 1-to-4 splitter is significant here. It's just unfortunate that the Thunderbolt is not clearer about it. > Why do I want to get this unit up and running: this unit has been tested > to have very good phase noise performance. I'll use anyone's low noise > source anyday. Which is also why I like to see mine operational, alongside my Z3801, GPS-4 and others. Cheers, Magnus From magnus at rubidium.dyndns.org Sun Nov 22 23:12:44 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 23 Nov 2009 00:12:44 +0100 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: <54363.87.227.52.225.1258924923.squirrel@webmail.lysator.liu.se> References: <54363.87.227.52.225.1258924923.squirrel@webmail.lysator.liu.se> Message-ID: <4B09C56C.1010900@rubidium.dyndns.org> bg at lysator.liu.se wrote: > Hi Nigel, > > AMU and SNR are two different scales. I do not have a translation. A > Kepler award recepient once explained Trimbles AMU as "a meaningless > unit". That said, SNR or C/N0 values cannot be directly compared between > different receivers since the measures might be taken at different points > in the receiver. AMU is just a scaled linear correlation measure. Either this is Ip or the vector sum of Ip and Qp. Ip would suffice onces locked in. C/N measure is a combination of that and that of the pre-correlator noise. Wither this has been done or not is unknown. > The Trimble monitor program can be made to switch between AMU and SNR in > one of the configuration menues. I think you might have switched to SNR. > > With above uncertanty of specific SNR definitions noted, most receivers > are enjoying an excellent signal if the highest elevation receivers have a > SNR above 50. If the highest SVs get +45dB that is still decent. This is where C/N excel over AMU, it's easier to compare to other receivers. Cheers, Magnus From jfor at quik.com Sun Nov 22 23:10:55 2009 From: jfor at quik.com (J. Forster) Date: Sun, 22 Nov 2009 15:10:55 -0800 (PST) Subject: [time-nuts] Alternate frequency sources - second opinions In-Reply-To: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <1972.12.6.201.37.1258931455.squirrel@popacctsnew.quik.com> > Hockey puck (or mouse) type GPS receivers are available for under $100. > > What can I get in that price range that doesn't depend on GPS? I'm > interested in millisecond accuracy as well as nanosecond. > > Has anybody built a WWVB-DO? (Time to dust off my WWVB toys.) > > Is there some good WWV setup? I have an HP 117A and loop. It works much of the time, but has diurnal night/day shifts of a good fraction of a 60 KHz cycle. It really takes continuous monitoring for several days to get good numbers. > Somebody mentioned TV and radio stations recently. (I think it was part > of the North discussion.) > > What sort of frequency source is at the root of the local TV or radio > stations? > > Is the sync timing for TV stations derived from the same source as the > carrier? Or are there two separate clocks to discuss? How about the > color-burst frequency? NTSC is gone w/ analog TV. No color burst any more. > What do radio/TV stations do for backups? If there was a hurricane or > earthquake that broke the main transmitter are they likely to switch to a > backup with a different timing source? I'm not sure, but when satellite links go down, the picture freezes. That implies a frame store which is likely bad news for timing. FWIW, -John =============== From GandalfG8 at aol.com Sun Nov 22 23:14:32 2009 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Sun, 22 Nov 2009 18:14:32 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: In a message dated 22/11/2009 21:23:49 GMT Standard Time, bg at lysator.liu.se writes: AMU and SNR are two different scales. I do not have a translation. A Kepler award recepient once explained Trimbles AMU as "a meaningless unit". That said, SNR or C/N0 values cannot be directly compared between different receivers since the measures might be taken at different points in the receiver. The Trimble monitor program can be made to switch between AMU and SNR in one of the configuration menues. I think you might have switched to SNR. ---------------------- Ah, that explains it, I wasn't aware there were two options but you're quite right. I don't recall switching it, and Thunderbolt Monitor doesn't seem to have the option to switch it anyway, but I found the option in GPSMon 1v05 and 1v6 and it can indeed be toggled. Whereas GPSMon changes the label of the field to suit it doesn't help that Thunderbolt Monitor leaves it described as AMU regardless of the setting:-) regards Nigel GM8PZR From GandalfG8 at aol.com Sun Nov 22 23:18:36 2009 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Sun, 22 Nov 2009 18:18:36 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: In a message dated 22/11/2009 21:48:14 GMT Standard Time, warrensjmail-one at yahoo.com writes: Concerning the relation of AMU to dBc, what I've seen is: AMU of 4 is in the high 30, AMU of 3 is in the mid 30, AMU of 2 is in the high 20, AMU of 1 is in the mid 20, A good outdoor antenna will give dBc in the high 40 to 50s and poor indoor antena will give dBc in the mid 30's AND still works fine, and anything above 25 dBc works OK when in the fixed position 'Overdetermined Clock' mode. -------------- Hi Warren That's just what I was looking for and the rest of your post was very informative too, definitely one I'll save for reference. Many thanks Nigel GM8PZR From hmurray at megapathdsl.net Sun Nov 22 23:24:41 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sun, 22 Nov 2009 15:24:41 -0800 Subject: [time-nuts] backup to GPS after jan 2010, was: OT - GPS and North In-Reply-To: Message from Stanley Reynolds of "Sun, 22 Nov 2009 14:49:32 PST." <42030.25546.qm@web30308.mail.mud.yahoo.com> Message-ID: <20091122232442.37D8EBCFC@ip-64-139-1-69.sjc.megapath.net> stanley_reynolds at yahoo.com said: > Further if at least one cell site has a accurate clock how far could > it be repeated before it lost it's useful accuracy using the CDMA > signal as in : I think there are two cases. The first is if the GPS receiver on a single site breaks, I think it would be reasonable to have that site lock on to it's neighbors. The second case is when GPS dies so that all CMDA sites need to coordinate time without help from GPS. Chains of PLLs are tricky. If they didn't need GPS they probably wouldn't have used it to begin with. I think you could do it if each site had a rubidium or something that was stable enough. I don't know what "enough" means. I think the key idea is something like the time constants for distributing the information have to be much faster than the time constant for tweaking the local clock. That is all the sites have to agree on what to do and understand where they fit into the plan. Early SONET ran into troubles with chains of PLLs. I forget the details if I ever knew them. I think they got the time constants wrong and ended up amplifying noise in a certain band rather than filtering it out. If you told me the stability of the local clock and the round trip times to adjacent cells and how much bandwidth I could use and such, I could probably come up with a stable algorithm and tell you how far and/or how many hops it would work over. -- These are my opinions, not necessarily my employer's. I hate spam. From stanley_reynolds at yahoo.com Sun Nov 22 23:36:27 2009 From: stanley_reynolds at yahoo.com (Stanley Reynolds) Date: Sun, 22 Nov 2009 15:36:27 -0800 (PST) Subject: [time-nuts] Alternate frequency sources - second opinions In-Reply-To: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <535603.37092.qm@web30301.mail.mud.yahoo.com> The lack of low cost options to GPS is the point, loran as a backup is not as good or cheap, it is just the next best. WWVB is good if you are close that is you are in ground wave range. Loran depends on ground wave and can reject skywave some of this is made better via loran pulse nature. Maybe cheap cesium clocks will be on ebay soon, but I would not count on it as it takes a very long time to go from decommissioned loran station to ebay. see table 2: http://tf.nist.gov/timefreq/general/pdf/1305.pdf Would indicate wwvb would be better than wwv for frequency or time. I have been playing with a wwvb?DO but my location is marginal for reception. Stanley ----- Original Message ---- From: Hal Murray To: time-nuts at febo.com Sent: Sun, November 22, 2009 4:39:56 PM Subject: [time-nuts] Alternate frequency sources - second opinions Hockey puck (or mouse) type GPS receivers are available for under $100. What can I get in that price range that doesn't depend on GPS?? I'm interested in millisecond accuracy as well as nanosecond. Has anybody built a WWVB-DO?? (Time to dust off my WWVB toys.) Is there some good WWV setup? Somebody mentioned TV and radio stations recently.? (I think it was part of the North discussion.) What sort of frequency source is at the root of the local TV or radio stations? Is the sync timing for TV stations derived from the same source as the carrier?? Or are there two separate clocks to discuss?? How about the color-burst frequency? What do radio/TV stations do for backups?? If there was a hurricane or earthquake that broke the main transmitter are they likely to switch to a backup with a different timing source? -- These are my opinions, not necessarily my employer's.? I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From magnus at rubidium.dyndns.org Sun Nov 22 23:45:54 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 23 Nov 2009 00:45:54 +0100 Subject: [time-nuts] Alternate frequency sources - second opinions In-Reply-To: <1972.12.6.201.37.1258931455.squirrel@popacctsnew.quik.com> References: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> <1972.12.6.201.37.1258931455.squirrel@popacctsnew.quik.com> Message-ID: <4B09CD32.5070109@rubidium.dyndns.org> J. Forster wrote: >> Somebody mentioned TV and radio stations recently. (I think it was part >> of the North discussion.) >> >> What sort of frequency source is at the root of the local TV or radio >> stations? >> >> Is the sync timing for TV stations derived from the same source as the >> carrier? Or are there two separate clocks to discuss? How about the >> color-burst frequency? > > NTSC is gone w/ analog TV. No color burst any more. There are other forms of pilot-signals in the OFDM spectrum. That is needed to keep the digital receiver frequency locked to the signal. Read the specs of your favorite terrestrial digital network of choice. >> What do radio/TV stations do for backups? If there was a hurricane or >> earthquake that broke the main transmitter are they likely to switch to a >> backup with a different timing source? > > I'm not sure, but when satellite links go down, the picture freezes. That > implies a frame store which is likely bad news for timing. That is what the MPEG-2/4 decode does. It stops updating it's play-out frame-buffer. It's not a frame-store by necessity. Cheers, Magnus From magnus at rubidium.dyndns.org Sun Nov 22 23:57:22 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 23 Nov 2009 00:57:22 +0100 Subject: [time-nuts] backup to GPS after jan 2010, was: OT - GPS and North In-Reply-To: <20091122232442.37D8EBCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091122232442.37D8EBCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <4B09CFE2.2000409@rubidium.dyndns.org> Hal Murray wrote: > stanley_reynolds at yahoo.com said: >> Further if at least one cell site has a accurate clock how far could >> it be repeated before it lost it's useful accuracy using the CDMA >> signal as in : > > I think there are two cases. > > The first is if the GPS receiver on a single site breaks, I think it would be > reasonable to have that site lock on to it's neighbors. > > The second case is when GPS dies so that all CMDA sites need to coordinate > time without help from GPS. Chains of PLLs are tricky. If they didn't need > GPS they probably wouldn't have used it to begin with. > > I think you could do it if each site had a rubidium or something that was > stable enough. I don't know what "enough" means. I think the key idea is > something like the time constants for distributing the information have to be > much faster than the time constant for tweaking the local clock. That is all > the sites have to agree on what to do and understand where they fit into the > plan. > > Early SONET ran into troubles with chains of PLLs. I forget the details if I ever knew them. > I think they got the time constants wrong and ended up amplifying noise in a certain band > rather than filtering it out. Not quite. What happends is that for each stretch and PLL adds some noise. At the same time the PLL also has some resonance at its loop bandwidth, resulting in a little gain. Say that you have 2 dB of gain in each stage and consider that you have 100 such PLLs in series. They have by design the same bandwidth and thus their 2 dB of gain occurs on more or less the same frequency and you have a 200 dB of jitter gain. Simulations done at Bell Labs (using one filter feedbacked throught a long cable) made this point painstakingly obvious. To combat this, a strategy was created where every once in a while a narrower bandwidth was applied, thus allowing to filter out the noise of the looser PLLs. Specs is set such that there is a healthy distance between narrower and broader PLL bandwidths, such that the broader PLLs does not provide jitter peaking too close the the narrower PLLs cut-off, such that enought of damping slope of the narrower PLLs is in use. The simple model provides STRATUM-1 (reference clock), STRATUM-2 (station clock), STRATUM-3 (equipment clock) and STRATUM-4 (line clock). With narrower PLLs comes higher requirements for stability, which also is important for hold-over. I haven't seen a good reference to all aspects of the SONET/SDH timing story, and they are a bit different between SONET and SDH. Cheers, Magnus From hmurray at megapathdsl.net Mon Nov 23 00:00:23 2009 From: hmurray at megapathdsl.net (Hal Murray) Date: Sun, 22 Nov 2009 16:00:23 -0800 Subject: [time-nuts] Alternate frequency sources - second opinions In-Reply-To: Message from "J. Forster" of "Sun, 22 Nov 2009 15:10:55 PST." <1972.12.6.201.37.1258931455.squirrel@popacctsnew.quik.com> Message-ID: <20091123000024.EA60CBCFC@ip-64-139-1-69.sjc.megapath.net> > I'm not sure, but when satellite links go down, the picture freezes. > That implies a frame store which is likely bad news for timing. I'm not sure that "bad news" is the right term. If you have frame buffers (and they were a big breakthrough many years ago), then you get timing from the output side of the frame buffer rather than the input side. The output side is your local TV station. If they have a good clock, you win. If not, oh well, maybe another station will be better. -- These are my opinions, not necessarily my employer's. I hate spam. From magnus at rubidium.dyndns.org Sun Nov 22 23:39:58 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 23 Nov 2009 00:39:58 +0100 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: Message-ID: <4B09CBCE.2010000@rubidium.dyndns.org> GandalfG8 at aol.com wrote: > > In a message dated 22/11/2009 21:23:49 GMT Standard Time, bg at lysator.liu.se > writes: > > AMU and SNR are two different scales. I do not have a translation. A > Kepler award recepient once explained Trimbles AMU as "a meaningless > unit". That said, SNR or C/N0 values cannot be directly compared between > different receivers since the measures might be taken at different points > in the receiver. > > The Trimble monitor program can be made to switch between AMU and SNR in > one of the configuration menues. I think you might have switched to SNR. > > > ---------------------- > Ah, that explains it, I wasn't aware there were two options but you're > quite right. > > I don't recall switching it, and Thunderbolt Monitor doesn't seem to have > the option to switch it anyway, but I found the option in GPSMon 1v05 and > 1v6 and it can indeed be toggled. The Thunderbolt Monitor does have it, I just ticked the box and had my C/N measures instead. In the "Setup" menu, select "Packet Masks and Options..." where you in the "Packer 35 Options" frame, the "Auxiliary (Byte 3)" sub-frame find a tick-box for "Output dBc/Hz". Tick the tick-box and press the "Set Options" button and you get dBc/Hz values rather than AMU values. > Whereas GPSMon changes the label of the field to suit it doesn't help that > Thunderbolt Monitor leaves it described as AMU regardless of the setting:-) A bit confusing indeed, but the values should never really overlap, so values should be a good hint on what to expect. Bottom line, use C/N values whenever you can. Cheers, Magnus From GandalfG8 at aol.com Mon Nov 23 00:21:21 2009 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Sun, 22 Nov 2009 19:21:21 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: In a message dated 23/11/2009 00:06:52 GMT Standard Time, magnus at rubidium.dyndns.org writes: The Thunderbolt Monitor does have it, I just ticked the box and had my C/N measures instead. In the "Setup" menu, select "Packet Masks and Options..." where you in the "Packer 35 Options" frame, the "Auxiliary (Byte 3)" sub-frame find a tick-box for "Output dBc/Hz". Tick the tick-box and press the "Set Options" button and you get dBc/Hz values rather than AMU values. ------------------ Yes, you're quite correct, obviously one of my not very observant days:-) --------------- > Whereas GPSMon changes the label of the field to suit it doesn't help that > Thunderbolt Monitor leaves it described as AMU regardless of the setting:-) A bit confusing indeed, but the values should never really overlap, so values should be a good hint on what to expect. -------------------- Agreed, once you're actually aware there's more than one option:-) regards Nigel GM8PZR From brooke at pacific.net Mon Nov 23 00:22:25 2009 From: brooke at pacific.net (Brooke Clarke) Date: Sun, 22 Nov 2009 16:22:25 -0800 Subject: [time-nuts] OT - GPS and North In-Reply-To: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> References: <12594164.527391258812312296.JavaMail.defaultUser@defaultHost> Message-ID: <4B09D5C1.6070901@pacific.net> Hi Antonio: That's an interesting question. It turns out that one of the key military applications of GPS, in addition to position and time, is to find North to high accuracy. This is needed to be known to better that one grad (1/6400 of a circle). In that past it was done using a theodolite integrated with a gyroscope (AG8 (Kern DKM1) North Finding System). This system was heavy, cost the government about $250k and was very easy to break. http://www.prc68.com/I/Alidade.shtml#AG8 I think starting with the PLGR96 and now the DAGR there are two or more methods of accurately finding North. http://www.prc68.com/I/PLGR.shtml http://www.prc68.com/I/DAGR.shtml#GLS http://www.prc68.com/I/DAGR.shtml#AzD In one method you place the receiver on stake #1, go to stake #2 (while not obstructing the antenna to allow carrier phase tracking sats) then at stake #2 press enter and the GPS gives you the bearing and distance between the stakes. In another method two GPS receivers are used. One at stake #1 and the other first is synchronized to the one at stake #1 then moved to stake #2, press enter, and go back to stake #1 and reconnect the two units. Again you get bearing and distance between the stakes based on carrier phase processing inside the GPS unit. Have Fun, Brooke Clarke http://www.prc68.com iovane at inwind.it wrote: > Does a stationary (not in motion) GPS receiver know where the North is? > > As far > as I can understand, it doesn't, isn't it? > > Antonio I8IOV > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From warrensjmail-one at yahoo.com Mon Nov 23 00:34:03 2009 From: warrensjmail-one at yahoo.com (WarrenS) Date: Sun, 22 Nov 2009 16:34:03 -0800 Subject: [time-nuts] Thunderbolt reception problems Message-ID: <5C5D0692C552490E8FDA7FB1BF0D153E@WSOffice> >If you needed to lower your AMU limit from 4 to 2, you are feeding the >Thunderbolt a signal level below the intended levels. True, You MAY be feeding it a signal that is below what the cell site recommended High gain outdoor antenna will give it. But any conclusion past that sounds like pure speculation. And most of use are not using them in cell sites. I Can not comment on the other units Magnus referred to that don't work if set too low, and I can not say what AMU is in the Tbolt BUT I can say with certainty that setting it to a value of 1 or 2 with 'Tboltmon.exe' version 1.2 works fine and 1 works MUCH BETTER than 4 in some setup. Looks like the Tbolt software is not so dumb as to use sat signals that will screw it up. 'Trimble GPS Monitor V1-2.pdf' instructions on page 13 shows the "signal level mask (AMU) set to 0.6 ws **************** said >> In the end, it looks like this turned out to be a configuration issue >> rather than a receiver sensitivity issue. But this also begs the question: how >> much performance degradation will I get when using 2.0 as the AMU threshold >> rather than the factory default. There must have been a reason why Trimble >> set the default so high, they mention something about multipath rejection >> in the manual. >I kindly disagree... >... snip >If you needed to lower your AMU limit from 4 to 2, you are feeding the >Thunderbolt a signal level below the intended levels. >... >Cheers, >Magnus From brooke at pacific.net Mon Nov 23 00:35:34 2009 From: brooke at pacific.net (Brooke Clarke) Date: Sun, 22 Nov 2009 16:35:34 -0800 Subject: [time-nuts] OT - GPS and North Message-ID: <4B09D8D6.9040708@pacific.net> Hi Antonio: ---------------- That's an interesting question. It turns out that one of the key military applications of GPS, in addition to position and time, is to find North to high accuracy. This is needed to be known to better that one grad (1/6400 of a circle). In that past it was done using a theodolite integrated with a gyroscope (AG8 (Kern DKM1) North Finding System). This system was heavy, cost the government about $250k and was very easy to break. http://www.prc68.com/I/Alidade.shtml#AG8 I think starting with the PLGR96 and now the DAGR there are two or more methods of accurately finding North. http://www.prc68.com/I/PLGR.shtml http://www.prc68.com/I/DAGR.shtml#GLS http://www.prc68.com/I/DAGR.shtml#AzD In one method you place the receiver on stake #1, go to stake #2 (while not obstructing the antenna to allow carrier phase tracking sats) then at stake #2 press enter and the GPS gives you the bearing and distance between the stakes. In another method two GPS receivers are used. One at stake #1 and the other first is synchronized to the one at stake #1 then moved to stake #2, press enter, and go back to stake #1 and reconnect the two units. Again you get bearing and distance between the stakes based on carrier phase processing inside the GPS unit. --------------------- Many GPS receivers have a built in World Magnetic Model. It's just a 12th order polynomial fitted to the magnetic vector by Lon, Lat, Ele, date & time. They're good for 5 years, see: http://www.prc68.com/I/Sensors.shtml#EMF For example the military DAGR has a built in magnetic compass that has the deviation corrected based on the location and date so you can select either true or magnetic bearings. Using the magnetic compass drains the battery so there's an option to turn it off when not in use. There's no tilt correction so the GPS receiver needs to be held level when using the mag compass. Have Fun, Brooke Clarke http://www.prc68.com iovane at inwind.it wrote: > Does a stationary (not in motion) GPS receiver know where the North is? > > As far > as I can understand, it doesn't, isn't it? > > Antonio I8IOV > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From brooke at pacific.net Mon Nov 23 00:44:40 2009 From: brooke at pacific.net (Brooke Clarke) Date: Sun, 22 Nov 2009 16:44:40 -0800 Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B08AC79.10207@xtra.co.nz> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> <4B0887C1.8090009@xtra.co.nz> <1893.12.6.201.232.1258855982.squirrel@popacctsnew.quik.com> <4B08AC79.10207@xtra.co.nz> Message-ID: <4B09DAF8.9060302@pacific.net> Hi Bruce: Do you know where I might find connection information on the MD-1 star tracker used in the B-52? See: http://www.prc68.com/I/MD1.shtml The system was good to 1 arc minute (including temperature, pressure, etc.) and I've heard that the sensor was far better than that (into the arc second range). Have Fun, Brooke Clarke http://www.prc68.com Bruce Griffiths wrote: > When a star tracker is used as a stellar compass in effect takes > simultaneous fixes on several stars and the better ones are capable of > an rms error of a few arc seconds, largely limited by atmospheric > instability. > These are usually used for determining space vehicle attitude, in which > case the instability due to seeing is much smaller than when immersed in > the atmosphere. > They have been used as relatively inexpensive position encoders for > pointing a telescope to within a few arc seconds. > Pattern recognition techniques are used to identify stars in a > relatively wide field (a few degrees) slightly defocused image (improves > centroiding accuracy). > > Star tracker for Clementine mission: > http://www.osti.gov/bridge/servlets/purl/86977-ULkJcR/webviewable/86977.pdf > > A more accurate version: > http://www.newworldt.com/download/DTU/microASC%20Summary.pdf > > telescope pointing application: > http://www.ifa.hawaii.edu/faculty/pickles/AJP/spie3351.07.pdf > http://www.ifa.hawaii.edu/users/pickles/AJP/AMOS2003_v4.pdf > > Measuring the position (altitude + azimuth) of one star at a time using > a theodolite is not the most efficient method of determining the > direction of the meridian. > Its far better to measure the position of several stars at once as in > the stellar compass, however a longer focal length camera lens than > usually used in a star tracker is desrable for increased accuracy. > > Bruce > > J. Forster wrote: >> Not so. I'm very familiar with laying in accurate North lines for gyro >> testing. To get anything close to accurate (1 arc second or better) takes >> many hours of stellar observation with a Wild T-3 class instrument. >> >> -John >> >> =============== >> >> >> >>> Neville Michie wrote: >>>> When you think of time specifications from GPS, the GPS system is a >>>> poor way to find north. >>>> Even with a base line of 1000 metres you only have a fraction of a >>>> degree. >>>> The GPS system may be useful to get accurate time to simplify a star >>>> observation, from a known (GPS) >>>> position on this planet, but finding north is still a problem because >>>> of the accuracy of a small >>>> number of observations from a star fix. >>>> Gyrocompasses take some time to get a measurement >>>> ( one hour) but even their estimate of North cannot match the >>>> precision that the GPS system can get us with time. >>>> cheers, Neville Michie >>> If you are taking star shots a stellar compass can easily provide a >>> boresight pointing accuracy of a few arcsec. >>> >>> Bruce >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts at febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From tvb at LeapSecond.com Mon Nov 23 00:56:54 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Sun, 22 Nov 2009 16:56:54 -0800 Subject: [time-nuts] OT - GPS and North References: Message-ID: >> You could (temporarily) install a structure that blocks reception in one >> direction and then infer the meridian direction from the occultation of >> SVs by the obstruction. >> However the accuracy of the determination wont be high. >> >> Bruce > > Anyway, that's an idea. > > Antonio The other way to find North is to monitor the shadow cast by the "temporary structure". For details, google sundial. /tvb From magnus at rubidium.dyndns.org Mon Nov 23 01:03:41 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 23 Nov 2009 02:03:41 +0100 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: <5C5D0692C552490E8FDA7FB1BF0D153E@WSOffice> References: <5C5D0692C552490E8FDA7FB1BF0D153E@WSOffice> Message-ID: <4B09DF6D.7010107@rubidium.dyndns.org> Warren, WarrenS wrote: >> If you needed to lower your AMU limit from 4 to 2, you are feeding the >> Thunderbolt a signal level below the intended levels. > > True, You MAY be feeding it a signal that is below what the cell site recommended High gain outdoor antenna will give it. > But any conclusion past that sounds like pure speculation. And most of use are not using them in cell sites. True, but lowering this value should be a warning-sign that you may not get the performance of the spec-sheet. There where some debate on wither the signal level was an issue or not. Lowering the AMU limit only lowers the acceptance level of signal strength for a sat in view to be accepted for tracking. Regardless how AMU is cooked up (an issue we could ponder over as a side-track), it remains a signal strength measure. > I Can not comment on the other units Magnus referred to that don't work if set too low, > and I can not say what AMU is in the Tbolt > BUT I can say with certainty that setting it to a value of 1 or 2 with 'Tboltmon.exe' version 1.2 works fine > and 1 works MUCH BETTER than 4 in some setup. > Looks like the Tbolt software is not so dumb as to use sat signals that will screw it up. It uses the AMU limit to select among the available sats. It then uses the T-RAIM to cancel out any outliners among that subset of sats to churn out which sats is being used for positioning/timing solution. The AMU limit is nothing magic, it's only that we don't have a good reference to what the AMU value is in detail, but we do know that high values is good and low values is bad. Lowering the AMU value as you did is good in the sense that you got more sats to actively track. It is bad that the signal levels the Thunderbolt is experience is so low that you need to take that action. Low signal values means more timing noise and thus more timing instabilty. Having a few sats is better than none. So it is an indication that the unit would like some more gain... 10 dB or so. > 'Trimble GPS Monitor V1-2.pdf' instructions on page 13 shows the "signal level mask (AMU) set to 0.6 If the statement that AMU is a linear scale is correct, that would mean that the C/N limit is set 16,5 dB lower than normally, i.e. that C/N being 16,5 dB lower can be accepted. It would be fun to play around with a variable damper to see what relationship to level the AMU value is on the Thunderbolt. Cheers, Magnus From alan.melia at btinternet.com Mon Nov 23 01:04:44 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 23 Nov 2009 01:04:44 -0000 Subject: [time-nuts] Alternate frequency sources - second opinions References: <20091123000024.EA60CBCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <005c01ca6bd8$fe06d8d0$0900a8c0@lark> I cant remember the detail now but my converstaion with a BBC engineer at the NPL meeting a few years back suggested along the lines of "yes there would be a stable frequency available on a digital TV signal but no it would not be related (tracable) to any given standard because it didnt need to be." It may be a case of measure it and see !! TVADEV ?? :-)) Alan G3NYK ----- Original Message ----- From: "Hal Murray" To: "Discussion of precise time and frequency measurement" Sent: Monday, November 23, 2009 12:00 AM Subject: Re: [time-nuts] Alternate frequency sources - second opinions > > > I'm not sure, but when satellite links go down, the picture freezes. > > That implies a frame store which is likely bad news for timing. > > I'm not sure that "bad news" is the right term. > > If you have frame buffers (and they were a big breakthrough many years ago), > then you get timing from the output side of the frame buffer rather than the > input side. The output side is your local TV station. If they have a good > clock, you win. If not, oh well, maybe another station will be better. > > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From bruce.griffiths at xtra.co.nz Mon Nov 23 01:25:05 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 23 Nov 2009 14:25:05 +1300 Subject: [time-nuts] OT - GPS and North In-Reply-To: <4B09DAF8.9060302@pacific.net> References: <292414.4587.qm@web38803.mail.mud.yahoo.com> <4B08704B.4020707@garychatters.com> <61190.87.227.52.225.1258845588.squirrel@webmail.lysator.liu.se> <4B0887C1.8090009@xtra.co.nz> <1893.12.6.201.232.1258855982.squirrel@popacctsnew.quik.com> <4B08AC79.10207@xtra.co.nz> <4B09DAF8.9060302@pacific.net> Message-ID: <4B09E471.2010903@xtra.co.nz> Brooke No idea about MD1 connections source. I can well believe that the photocell plus telescope is capable of arc second accuracy sensitivity. Zeiss used to offer a sun tracker as well as photomultiplier based tridant star sensor/trackers with sub arc second sensitiviy. Bruce Brooke Clarke wrote: > Hi Bruce: > > Do you know where I might find connection information on the MD-1 star > tracker used in the B-52? See: > http://www.prc68.com/I/MD1.shtml > > The system was good to 1 arc minute (including temperature, pressure, > etc.) and I've heard that the sensor was far better than that (into > the arc second range). > > Have Fun, > > Brooke Clarke > http://www.prc68.com > > Bruce Griffiths wrote: From bill at iaxs.net Mon Nov 23 01:32:56 2009 From: bill at iaxs.net (Bill Hawkins) Date: Sun, 22 Nov 2009 19:32:56 -0600 Subject: [time-nuts] Alternate frequency sources - second opinions In-Reply-To: <005c01ca6bd8$fe06d8d0$0900a8c0@lark> References: <20091123000024.EA60CBCFC@ip-64-139-1-69.sjc.megapath.net> <005c01ca6bd8$fe06d8d0$0900a8c0@lark> Message-ID: IIRC, NTP turns a computer clock into a DO with millisecond accuracy. Accuracy is stratified, with a number of Stratum 1 sources available. Don't know if anyone has designed a collection of differentiated silicon and stored programs that hooks to the internet and delivers a disciplined 10 MHz at 50 ohms. Probably not, since even crystal oscillators do better than NTP. Beat one against WWV and you were good to 10-7 or so. Mills was working on microsecond accuracy five years ago. Where does NTP stand now? Bill Hawkins From rmoncur at bigpond.net.au Mon Nov 23 01:39:23 2009 From: rmoncur at bigpond.net.au (Rex Moncur) Date: Mon, 23 Nov 2009 12:39:23 +1100 Subject: [time-nuts] OT - GPS and North In-Reply-To: References: Message-ID: <000601ca6bdd$c8e8e0d0$5abaa270$@net.au> Given that we cannot do it with one GPS in a fixed position I would like to get people's ideas on whether there is a reasonable cost way (say less than $2K) to do it with two GPSs to get within a say half a degree. The application is to find azimuth headings for Amateur radio microwave or lightwave experiments. One cannot normally do star shots due to either day light or clouds. Let us assume that you can run the two GPS's over a baseline of 100 meters. At present I can get to within about plus/minus two degrees by walking an inexpensive handheld GPS over a baseline of 100 meters but I want to do better than that. For the hopefully more accurate measurement I would place one GPS and antenna at the microwave dish or lightwave transmitter and the other would be set up 100 meters away roughly in the direction one needed to beam. When a bearing was found one could either readjust the position of the remote GPS antenna to improve the accuracy or just allow for any error by beaming by this amount to the GPS unit. Let us assume that both GPS antennas are in a fixed location and the results can be averaged over say 30 minutes to improve the accuracy. I assume also that many of the errors due to propagation would cancel over such a short path. The data from both GPSs would be fed to a laptop over say RS232 line which I hope would work for 100 meters (perhaps 50 meters each way if necessary). The Laptop would have software to process that data and provide a bearing between the two antennas. Can anyone comment on: (a) the likely accuracy of such a system (b) whether there is any software out there that can do this. (c) the recommended GPS units for this application. (d) whether there is something one could purchase as a complete package at a reasonable cost (ie less than $2k) 73 Rex VK7MO -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of iovane at inwind.it Sent: Monday, 23 November 2009 8:08 AM To: time-nuts Subject: Re: [time-nuts] OT - GPS and North Thanks all. The conclusion seems to be that an ordinary and stationary GPS receiver with a single omnidiretional antenna knows very well where satellites are relative to the true North, and where the true North is relative to satellites, but doesn't know (more precisely: can't indicate, as it lacks another reference) where satellites or the North actually are. Eventually this appears quite obvious. Antonio I8IOV _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From SAIDJACK at aol.com Mon Nov 23 01:52:14 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Sun, 22 Nov 2009 20:52:14 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: Hi Nigel, et. al., I just changed the setting to C/No with the help of the instructions posted here; learned yet something else. With that I now get between 30 and 36dBc/Hz C/No (at night, which usually results in higher values than during daylight). I am impatient, and expect my equipment to be plug-and-play, this is what cause my frustration and surprise in the first place, since I did not have a problem with this antenna feed in the past. Due to the lack of a "lock" LED, and these issues, I guess I will have to dedicate an RS-232 to constantly monitor the unit, and be content with it's performance when connected to the splitter. That's better than drilling another hole into the wall and mounting another antenna on the roof. Thanks for everyone's help, bye, Said In a message dated 11/22/2009 12:14:01 Pacific Standard Time, GandalfG8 at aol.com writes: Just out of interest, what levels of AMU are you seeing reported? According to Trimble's Thunderbolt Monitor version 2.6 the six satellites I'm tracking right now are showing AMU values of over 40 and another stops tracking when its AMU drops to approx 33 but starts tracking again at a reported AMU of approx 36 to 37. From brooke at pacific.net Mon Nov 23 02:04:04 2009 From: brooke at pacific.net (Brooke Clarke) Date: Sun, 22 Nov 2009 18:04:04 -0800 Subject: [time-nuts] OT - GPS and North In-Reply-To: <000601ca6bdd$c8e8e0d0$5abaa270$@net.au> References: <000601ca6bdd$c8e8e0d0$5abaa270$@net.au> Message-ID: <4B09ED94.9050003@pacific.net> Hi Rex: You can do it with a single GPS (DAGR or PLGR96 or higher) with a 100 meter baseline. See: http://www.prc68.com/I/DAGR.shtml#GLS http://www.prc68.com/I/DAGR.shtml#AzD Have Fun, Brooke Clarke http://www.prc68.com Rex Moncur wrote: > Given that we cannot do it with one GPS in a fixed position I would like to > get people's ideas on whether there is a reasonable cost way (say less than > $2K) to do it with two GPSs to get within a say half a degree. > > > The application is to find azimuth headings for Amateur radio microwave or > lightwave experiments. One cannot normally do star shots due to either day > light or clouds. > > Let us assume that you can run the two GPS's over a baseline of 100 meters. > At present I can get to within about plus/minus two degrees by walking an > inexpensive handheld GPS over a baseline of 100 meters but I want to do > better than that. For the hopefully more accurate measurement I would place > one GPS and antenna at the microwave dish or lightwave transmitter and the > other would be set up 100 meters away roughly in the direction one needed to > beam. When a bearing was found one could either readjust the position of the > remote GPS antenna to improve the accuracy or just allow for any error by > beaming by this amount to the GPS unit. > > Let us assume that both GPS antennas are in a fixed location and the > results can be averaged over say 30 minutes to improve the accuracy. I > assume also that many of the errors due to propagation would cancel over > such a short path. The data from both GPSs would be fed to a laptop over > say RS232 line which I hope would work for 100 meters (perhaps 50 meters > each way if necessary). The Laptop would have software to process that data > and provide a bearing between the two antennas. Can anyone comment on: > > (a) the likely accuracy of such a system > (b) whether there is any software out there that can do this. > (c) the recommended GPS units for this application. > (d) whether there is something one could purchase as a complete package at a > reasonable cost (ie less than $2k) > > 73 Rex VK7MO > > > > > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of iovane at inwind.it > Sent: Monday, 23 November 2009 8:08 AM > To: time-nuts > Subject: Re: [time-nuts] OT - GPS and North > > Thanks all. > > The conclusion seems to be that an ordinary and stationary GPS receiver with > a single > omnidiretional antenna knows very well where satellites are relative to the > true North, > and where the true North is relative to satellites, but doesn't know (more > precisely: > can't indicate, as it lacks another reference) where satellites or the North > actually are. > Eventually this appears quite obvious. > > Antonio I8IOV > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From paulswedb at gmail.com Mon Nov 23 03:02:54 2009 From: paulswedb at gmail.com (paul swed) Date: Sun, 22 Nov 2009 22:02:54 -0500 Subject: [time-nuts] Alternate frequency sources - second opinions In-Reply-To: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091122223957.98AA0BCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: Well we are looking at alternates these days and indeed the tv signal ain't what it used to be. Though even though network blackburst was cesium derived local station butchered it.. But the good news is this the new dtv indeed does contain some pretty good clocks and in theory things like the pcr might be used. I have a dtv stb exactly to explore that possibility. You know the coupon boxes at walmart. But have a bunch of current distractions in line before I hack into that project. Regards On Sun, Nov 22, 2009 at 5:39 PM, Hal Murray wrote: > > Hockey puck (or mouse) type GPS receivers are available for under $100. > > What can I get in that price range that doesn't depend on GPS? I'm > interested in millisecond accuracy as well as nanosecond. > > Has anybody built a WWVB-DO? (Time to dust off my WWVB toys.) > > Is there some good WWV setup? > > > Somebody mentioned TV and radio stations recently. (I think it was part of > the North discussion.) > > What sort of frequency source is at the root of the local TV or radio > stations? > > Is the sync timing for TV stations derived from the same source as the > carrier? Or are there two separate clocks to discuss? How about the > color-burst frequency? > > What do radio/TV stations do for backups? If there was a hurricane or > earthquake that broke the main transmitter are they likely to switch to a > backup with a different timing source? > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From holrum at hotmail.com Mon Nov 23 03:36:04 2009 From: holrum at hotmail.com (Mark Sims) Date: Mon, 23 Nov 2009 03:36:04 +0000 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: Message-ID: I have considerable experience operating Thunderbolts in less than optimum conditions (my house is in an urban jungle, surrounded by Jurassic trees and nasty multipath monsters). Lady Heather defaults to the dBc setting since that seems to be the most understandable and better defined system. Signal levels above 40 are very good. There seems to be little to be gained with signals above 40. Above 35 are OK-ish. From 32-35 are usable, if you are not too picky about your system. Below 32 are just plain craptastic and pretty much unusable. The most problematic and intractable source of Tbolt output errors seem to be the result of satellite constellation changes as the unit constantly switches between satellites in an effort to track the "best" available satellites. If you plot the satellite count and DAC voltage (and along with the PPS error estimate) you will see that the DAC voltage changes with every satellite constellation change. This causes the oscillator to change frequency. The better your signal levels, the less reason the unit has to switch tracked satellites and the better will be your oscillator and PPS outputs. The Tbolt firmware supplies few tools for minimizing its annoying habit of tracking the supposedly "best" satellites of any given instant. At my location, I am doing real good if the tracked satellite constellation stays fixed for over a minute... _________________________________________________________________ Windows 7: I wanted simpler, now it's simpler. I'm a rock star. http://www.microsoft.com/Windows/windows-7/default.aspx?h=myidea?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_myidea:112009 From holrum at hotmail.com Mon Nov 23 05:25:22 2009 From: holrum at hotmail.com (Mark Sims) Date: Mon, 23 Nov 2009 05:25:22 +0000 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: Message-ID: Something in the last post got cut off... Anything you can do to minimize satellite constellation changes is good. If reducing the signal level cutoff threshold or changing the elevation mask angle works for your installation, go for it. It appears that the effects of constellation changes is worse than the effects of low signal levels. _________________________________________________________________ Bing brings you maps, menus, and reviews organized in one place. http://www.bing.com/search?q=restaurants&form=MFESRP&publ=WLHMTAG&crea=TEXT_MFESRP_Local_MapsMenu_Resturants_1x1 From warrensjmail-one at yahoo.com Mon Nov 23 06:08:17 2009 From: warrensjmail-one at yahoo.com (WarrenS) Date: Sun, 22 Nov 2009 22:08:17 -0800 Subject: [time-nuts] Thunderbolt reception problems Message-ID: <219A03EF4544423C8BBA6601054D3118@WSOffice> Mark Sounds like the same problem I had when I had the AMU set TOO high. ( I don't think it can be set with LH, Need Tboltmon to change it) I have not seen the condition that you describe where the Tbolt will switch satellites just because it has found a better one. (I don't think that happens) Mine will hold all eight and will not release any unless the signal level goes below the AMU setting. I do not know of any other way that will causes a satellite to switch out in only a few minutes when tracking under 8. When I had the AMU set too high, and the signal level was right at the bounty, then the satellites would tend to toggle in and out as you described. The solution for me was to set the AMU to one so that the Tbolt did not release a satellite once it got it, and I also raised the elevation mask so that it did not pick up the satellite until the satellite got higher and stronger in the sky. In my location which sounds similar to yours, with Elevation set high and the AMU set low it no longer toggles. As you said the worse thing for noise is when the Tbolt toggles the satellites in and out. This is much worse than holding a low level noisy signal. My unit works fine now with the TC set to 750+ seconds when there is ANY signal at least in the high 20s, which is always the case at my location. The High TC setting of 500+ and a damping setting of 0.7 (and Dac gain set correct) greatly helps in reducing the noise cause by satellites switching. ws ****************** Mark Sims said: I have considerable experience operating Thunderbolts in less than optimum conditions (my house is in an urban jungle, surrounded by Jurassic trees and nasty multipath monsters). Lady Heather defaults to the dBc setting since that seems to be the most understandable and better defined system. Signal levels above 40 are very good. There seems to be little to be gained with signals above 40. Above 35 are OK-ish. From 32-35 are usable, if you are not too picky about your system. Below 32 are just plain craptastic and pretty much unusable. The most problematic and intractable source of Tbolt output errors seem to be the result of satellite constellation changes as the unit constantly switches between satellites in an effort to track the "best" available satellites. If you plot the satellite count and DAC voltage (and along with the PPS error estimate) you will see that the DAC voltage changes with every satellite constellation change. This causes the oscillator to change frequency. The better your signal levels, the less reason the unit has to switch tracked satellites and the better will be your oscillator and PPS outputs. The Tbolt firmware supplies few tools for minimizing its annoying habit of tracking the supposedly "best" satellites of any given instant. At my location, I am doing real good if the tracked satellite constellation stays fixed for over a minute... From warrensjmail-one at yahoo.com Mon Nov 23 07:09:40 2009 From: warrensjmail-one at yahoo.com (WarrenS) Date: Sun, 22 Nov 2009 23:09:40 -0800 Subject: [time-nuts] Thunderbolt reception problems References: <5C5D0692C552490E8FDA7FB1BF0D153E@WSOffice> <4B09DF6D.7010107@rubidium.dyndns.org> Message-ID: Some of the disagreement has to do with the fact that Two similar topics, each with a different answer are being mixed together here. Magnus's point: 1) How to make the Tbolt the best that it can be? Answer: Start with a good strong signal and a quiet environment. Said's situation: 2) How to make the Tbolt work the best that it can with a less than optimized existing setup. Answer: Lower the AMU to 1, rise the elevation to 15or20, increase the TC setting to 500 sec. (It will work better than when the factory defaults are use with the #1 case above) Interesting enough, I have both cases with optimized setting running on my bench now and although the #1 is generally about 25% to 50% quieter, It is not always so. About 25% of the time the #2 case is as quiet or quieter. So the less than perfect #2 case is not really a big deal to most. There are much more important things that can be done if one likes to 'tweak & fiddle'. concerning: > that you may not get the performance of the spec-sheet. Not a problem, cause they seem careful not to include any specs concerning this except for the 1e-12 per day average. ws ******************** ----- Original Message ----- From: "Magnus Danielson" To: "WarrenS" ; "Discussion of precise time and frequency measurement" Sent: Sunday, November 22, 2009 5:03 PM Subject: Re: [time-nuts] Thunderbolt reception problems > Warren, > > WarrenS wrote: >>> If you needed to lower your AMU limit from 4 to 2, you are feeding the >>> Thunderbolt a signal level below the intended levels. >> >> True, You MAY be feeding it a signal that is below what the cell site recommended High gain outdoor antenna will give it. >> But any conclusion past that sounds like pure speculation. And most of use are not using them in cell sites. > > True, but lowering this value should be a warning-sign that you may not > get the performance of the spec-sheet. There where some debate on wither > the signal level was an issue or not. Lowering the AMU limit only lowers > the acceptance level of signal strength for a sat in view to be accepted > for tracking. Regardless how AMU is cooked up (an issue we could ponder > over as a side-track), it remains a signal strength measure. > >> I Can not comment on the other units Magnus referred to that don't work if set too low, >> and I can not say what AMU is in the Tbolt >> BUT I can say with certainty that setting it to a value of 1 or 2 with 'Tboltmon.exe' version 1.2 works fine >> and 1 works MUCH BETTER than 4 in some setup. >> Looks like the Tbolt software is not so dumb as to use sat signals that will screw it up. > > It uses the AMU limit to select among the available sats. It then uses > the T-RAIM to cancel out any outliners among that subset of sats to > churn out which sats is being used for positioning/timing solution. > > The AMU limit is nothing magic, it's only that we don't have a good > reference to what the AMU value is in detail, but we do know that high > values is good and low values is bad. > > Lowering the AMU value as you did is good in the sense that you got more > sats to actively track. It is bad that the signal levels the Thunderbolt > is experience is so low that you need to take that action. Low signal > values means more timing noise and thus more timing instabilty. Having a > few sats is better than none. > > So it is an indication that the unit would like some more gain... 10 dB > or so. > >> 'Trimble GPS Monitor V1-2.pdf' instructions on page 13 shows the "signal level mask (AMU) set to 0.6 > > If the statement that AMU is a linear scale is correct, that would mean > that the C/N limit is set 16,5 dB lower than normally, i.e. that C/N > being 16,5 dB lower can be accepted. > > It would be fun to play around with a variable damper to see what > relationship to level the AMU value is on the Thunderbolt. > > Cheers, > Magnus > > > From vogelchr at vogel.cx Mon Nov 23 08:45:20 2009 From: vogelchr at vogel.cx (Christian Vogel) Date: Mon, 23 Nov 2009 09:45:20 +0100 Subject: [time-nuts] Alternate frequency sources : DVB-T and ISDN? In-Reply-To: <005c01ca6bd8$fe06d8d0$0900a8c0@lark> References: <20091123000024.EA60CBCFC@ip-64-139-1-69.sjc.megapath.net> <005c01ca6bd8$fe06d8d0$0900a8c0@lark> Message-ID: <20091123094520.12942p458v82bag0@webmail.df.eu> Hi Alan, > I cant remember the detail now but my converstaion with a BBC engineer at > the NPL meeting a few years back suggested along the lines of "yes there > would be a stable frequency available on a digital TV signal but no it would > not be related (tracable) to any given standard because it didnt need to > be." at least here in Germany the digital TV transmissions (DVB-T) are using (in some areas) Single Frequency Networks[1]. I live near one of the transmitters and when I visited the facility, they had Meinberg GPS receivers in the racks housing the TV signal generators. Speaking of alternate sources: Has any time-nut considered using the ISDN telephone network [2]? Chris [1] http://en.wikipedia.org/wiki/Single-frequency_network [2] http://openbsc.gnumonks.org/trac/wiki/isdnsync From df6jb at ulrich-bangert.de Mon Nov 23 08:49:33 2009 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Mon, 23 Nov 2009 09:49:33 +0100 Subject: [time-nuts] Help on HP/Agilent 8563E / 83620A needed Message-ID: <44719722E35F4FB1B8E028CAA3780CBF@athlon> Gentlemen, if anyone of you has the circuit diagram of a 8563A's A14 and A15 circuit boards available, this would be of great help to a friend of mine. He is also in search for a 83620A service manual. Best regards Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener From bruce.griffiths at xtra.co.nz Mon Nov 23 09:12:48 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 23 Nov 2009 22:12:48 +1300 Subject: [time-nuts] Help on HP/Agilent 8563E / 83620A needed In-Reply-To: <44719722E35F4FB1B8E028CAA3780CBF@athlon> References: <44719722E35F4FB1B8E028CAA3780CBF@athlon> Message-ID: <4B0A5210.80300@xtra.co.nz> Ulrich Bangert wrote: > Gentlemen, > > if anyone of you has the circuit diagram of a 8563A's A14 and A15 circuit > boards available, this would be of great help to a friend of mine. He is > also in search for a 83620A service manual. > > Best regards > > Ulrich Bangert > www.ulrich-bangert.de > Ortholzer Weg 1 > 27243 Gross Ippener > > > _______________________________________________ > 83620A service manual: ftp://ftp.agilent.com/pub/manuals/08360-90049%2083620A%2022A%2023A%2024A%2030A%2040A%2050A%20Service%20Nov95.pdf Bruce From magnus at rubidium.dyndns.org Mon Nov 23 09:13:15 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 23 Nov 2009 10:13:15 +0100 Subject: [time-nuts] Alternate frequency sources : DVB-T and ISDN? In-Reply-To: <20091123094520.12942p458v82bag0@webmail.df.eu> References: <20091123000024.EA60CBCFC@ip-64-139-1-69.sjc.megapath.net> <005c01ca6bd8$fe06d8d0$0900a8c0@lark> <20091123094520.12942p458v82bag0@webmail.df.eu> Message-ID: <4B0A522B.3080502@rubidium.dyndns.org> Christian Vogel wrote: > Hi Alan, > >> I cant remember the detail now but my converstaion with a BBC engineer at >> the NPL meeting a few years back suggested along the lines of "yes there >> would be a stable frequency available on a digital TV signal but no it >> would >> not be related (tracable) to any given standard because it didnt need to >> be." > > at least here in Germany the digital TV transmissions (DVB-T) are using > (in some areas) Single Frequency Networks[1]. I live near one of the > transmitters > and when I visited the facility, they had Meinberg GPS receivers in the > racks housing the TV signal generators. SFN requires synchronisation of frequency (10 MHz) and phase (PPS). DVB-T transmitters using SFN will broadcast pilot-tones. See ETSI EN 300 744, accessable through: http://www.dvb.org/technology/standards/ > Speaking of alternate sources: Has any time-nut considered using the ISDN > telephone network [2]? I think ISDN is finally dead here in Sweden. I can check if my ISDN connection is out for good. However, I wonder if the modern replacement to ISDN, such as ADSL is actually synchronised. It too uses OFDM/COFDM transmission and provides pilot-tones. > Chris > > [1] http://en.wikipedia.org/wiki/Single-frequency_network > [2] http://openbsc.gnumonks.org/trac/wiki/isdnsync Cheers, Magnus From jmiles at pop.net Mon Nov 23 09:30:25 2009 From: jmiles at pop.net (John Miles) Date: Mon, 23 Nov 2009 01:30:25 -0800 Subject: [time-nuts] Help on HP/Agilent 8563E / 83620A needed In-Reply-To: <44719722E35F4FB1B8E028CAA3780CBF@athlon> Message-ID: http://www.artekmedia.com has scans of the 8560E-series schematics, which may not be too different from the -A suffix if he gets desperate. Also try hp_agilent_equipment on Yahoo Groups. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of Ulrich Bangert > Sent: Monday, November 23, 2009 12:50 AM > To: Time nuts > Subject: [time-nuts] Help on HP/Agilent 8563E / 83620A needed > > > Gentlemen, > > if anyone of you has the circuit diagram of a 8563A's A14 and A15 circuit > boards available, this would be of great help to a friend of mine. He is > also in search for a 83620A service manual. > > Best regards > > Ulrich Bangert > www.ulrich-bangert.de > Ortholzer Weg 1 > 27243 Gross Ippener > > > From iovane at inwind.it Mon Nov 23 10:24:54 2009 From: iovane at inwind.it (iovane at inwind.it) Date: Mon, 23 Nov 2009 11:24:54 +0100 Subject: [time-nuts] OT - GPS and North Message-ID: > >> You could (temporarily) install a structure that blocks reception in one > >> direction and then infer the meridian direction from the occultation of > >> SVs by the obstruction. > >> However the accuracy of the determination wont be high. > >> > >> Bruce > > > > Anyway, that's an idea. > > > > Antonio > > The other way to find North is to monitor the shadow cast > by the "temporary structure". For details, google sundial. > > /tvb Would be more accurate, for sure, but not good at night :-). Antonio From dave at uk-ar.co.uk Mon Nov 23 12:40:34 2009 From: dave at uk-ar.co.uk (Dave Baxter) Date: Mon, 23 Nov 2009 12:40:34 -0000 Subject: [time-nuts] [OT] North In-Reply-To: Message-ID: For that you need a Moondial! ;-) In the old days... Cub Scouts were taught to find a basic direction from the way moss grew on the south facing (in the Northern Hemesphere at least) side of trees. These days, it's easier to tell them to look at Sky TV dish's. (UK satellite TV service) Dave B. > -----Original Message----- > > > > The other way to find North is to monitor the shadow cast by the > > "temporary structure". For details, google sundial. > > > > /tvb > > Would be more accurate, for sure, but not good at night :-). > Antonio From ian.sheffield1 at tesco.net Mon Nov 23 13:00:43 2009 From: ian.sheffield1 at tesco.net (Ian Sheffield) Date: Mon, 23 Nov 2009 13:00:43 -0000 Subject: [time-nuts] [OT] North References: Message-ID: <004101ca6c3c$f8535990$0201a8c0@cookie> Didn't the moss grow on the North facing, cool side? ----- Original Message ----- From: "Dave Baxter" To: Sent: Monday, November 23, 2009 12:40 PM Subject: [time-nuts] [OT] North > For that you need a Moondial! ;-) > > > In the old days... Cub Scouts were taught to find a basic direction > from the way moss grew on the south facing (in the Northern Hemesphere > at least) side of trees. > > These days, it's easier to tell them to look at Sky TV dish's. (UK > satellite TV service) > > > Dave B. > > >> -----Original Message----- >> > >> > The other way to find North is to monitor the shadow cast by the >> > "temporary structure". For details, google sundial. >> > >> > /tvb >> >> Would be more accurate, for sure, but not good at night :-). >> Antonio > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -------------------------------------------------------------------------------- Internal Virus Database is out of date. Checked by AVG - www.avg.com Version: 8.5.425 / Virus Database: 270.14.64/2501 - Release Date: 11/13/09 18:22:00 From didier at cox.net Mon Nov 23 14:17:34 2009 From: didier at cox.net (Didier Juges) Date: Mon, 23 Nov 2009 08:17:34 -0600 Subject: [time-nuts] [OT] North In-Reply-To: References: Message-ID: <44EFE05C5B9540A195BF1C46F646FA93@d400> Dave, That may be why there are not so many Cub Scouts any more... They got lost on the way home. Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Dave Baxter > Sent: Monday, November 23, 2009 6:41 AM > To: time-nuts at febo.com > Subject: [time-nuts] [OT] North > > For that you need a Moondial! ;-) > > > In the old days... Cub Scouts were taught to find a basic > direction from the way moss grew on the south facing (in the > Northern Hemesphere at least) side of trees. > From jltran at worldnet.att.net Mon Nov 23 14:33:28 2009 From: jltran at worldnet.att.net (J. L. Trantham) Date: Mon, 23 Nov 2009 08:33:28 -0600 Subject: [time-nuts] Help on HP/Agilent 8563E / 83620A needed In-Reply-To: <44719722E35F4FB1B8E028CAA3780CBF@athlon> Message-ID: <4310F8D936204AA0A73876DB6DF42F2D@S0028384766> Check our item 270417502435 on e..y. Joe -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Ulrich Bangert Sent: Monday, November 23, 2009 2:50 AM To: Time nuts Subject: [time-nuts] Help on HP/Agilent 8563E / 83620A needed Gentlemen, if anyone of you has the circuit diagram of a 8563A's A14 and A15 circuit boards available, this would be of great help to a friend of mine. He is also in search for a 83620A service manual. Best regards Ulrich Bangert www.ulrich-bangert.de Ortholzer Weg 1 27243 Gross Ippener _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From justin at fuzzythinking.com Mon Nov 23 15:37:52 2009 From: justin at fuzzythinking.com (Justin Pinnix) Date: Mon, 23 Nov 2009 10:37:52 -0500 Subject: [time-nuts] OT - GPS and North In-Reply-To: <000601ca6bdd$c8e8e0d0$5abaa270$@net.au> References: <000601ca6bdd$c8e8e0d0$5abaa270$@net.au> Message-ID: Hi Rex, Sounds like a neat application. 100 meters might be a bit long for RS-232. I was taught that 50 feet is the limit for 9600bps. You may need to use RS-422 (balanced version of 232), low capacitance cable, or a lower baud rate. Since you're a ham, you could also do it wirelessly over UHF packet. You might even be able to use existing APRS hardware, provided it leaves you enough significant digits. 73 de AJ4MJ On Sun, Nov 22, 2009 at 8:39 PM, Rex Moncur wrote: > Given that we cannot do it with one GPS in a fixed position I would like to > get people's ideas on whether there is a reasonable cost way (say less than > $2K) to do it with two GPSs to get within a say half a degree. > > > The application is to find azimuth headings for Amateur radio microwave or > lightwave experiments. One cannot normally do star shots due to either day > light or clouds. > > Let us assume that you can run the two GPS's over a baseline of 100 meters. > At present I can get to within about plus/minus two degrees by walking an > inexpensive handheld GPS over a baseline of 100 meters but I want to do > better than that. For the hopefully more accurate measurement I would place > one GPS and antenna at the microwave dish or lightwave transmitter and the > other would be set up 100 meters away roughly in the direction one needed > to > beam. When a bearing was found one could either readjust the position of > the > remote GPS antenna to improve the accuracy or just allow for any error by > beaming by this amount to the GPS unit. > > Let us assume that both GPS antennas are in a fixed location and the > results can be averaged over say 30 minutes to improve the accuracy. I > assume also that many of the errors due to propagation would cancel over > such a short path. The data from both GPSs would be fed to a laptop over > say RS232 line which I hope would work for 100 meters (perhaps 50 meters > each way if necessary). The Laptop would have software to process that > data > and provide a bearing between the two antennas. Can anyone comment on: > > (a) the likely accuracy of such a system > (b) whether there is any software out there that can do this. > (c) the recommended GPS units for this application. > (d) whether there is something one could purchase as a complete package at > a > reasonable cost (ie less than $2k) > > 73 Rex VK7MO > > > > > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of iovane at inwind.it > Sent: Monday, 23 November 2009 8:08 AM > To: time-nuts > Subject: Re: [time-nuts] OT - GPS and North > > Thanks all. > > The conclusion seems to be that an ordinary and stationary GPS receiver > with > a single > omnidiretional antenna knows very well where satellites are relative to the > true North, > and where the true North is relative to satellites, but doesn't know (more > precisely: > can't indicate, as it lacks another reference) where satellites or the > North > actually are. > Eventually this appears quite obvious. > > Antonio I8IOV > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From djl at montana.com Mon Nov 23 16:23:45 2009 From: djl at montana.com (Don Latham) Date: Mon, 23 Nov 2009 09:23:45 -0700 (MST) Subject: [time-nuts] ocxo pinout Message-ID: <8ac63d7d35e375fe0fc44632267d133c.squirrel@webmail.montana.com> One of the group wanted a pinout for the eros funky frequency ocxo. Unfortunately, I lost the email. Could you email me again? Also, does your unit have a connector or plain pins? Are there two type SMB connectors? I have one of each type. Don -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com From garnere at gmail.com Mon Nov 23 17:12:57 2009 From: garnere at gmail.com (Eric Garner) Date: Mon, 23 Nov 2009 09:12:57 -0800 Subject: [time-nuts] OT - GPS and North In-Reply-To: References: <000601ca6bdd$c8e8e0d0$5abaa270$@net.au> Message-ID: alternately you could use a short-haul modem. I've used the ones from Telebyte running over with good success. you can get up to 115.2 kbps on ~1km of cable on some of them. http://www.telebyteusa.com/shorthaulmodem.htm -eric On Mon, Nov 23, 2009 at 7:37 AM, Justin Pinnix wrote: > Hi Rex, > > Sounds like a neat application. ?100 meters might be a bit long for RS-232. > I was taught that 50 feet is the limit for 9600bps. ?You may need to use > RS-422 (balanced version of 232), low capacitance cable, or a lower baud > rate. ?Since you're a ham, you could also do it wirelessly over UHF packet. > You might even be able to use existing APRS hardware, provided it leaves you > enough significant digits. > > 73 de AJ4MJ > > On Sun, Nov 22, 2009 at 8:39 PM, Rex Moncur wrote: > >> Given that we cannot do it with one GPS in a fixed position I would like to >> get people's ideas on whether there is a reasonable cost way (say less than >> $2K) to do it with two GPSs to get within a say half a degree. >> >> >> The application is to find azimuth headings for Amateur radio microwave or >> lightwave experiments. One cannot normally do star shots due to either day >> light or clouds. >> >> Let us assume that you can run the two GPS's over a baseline of 100 meters. >> At present I can get to within about plus/minus two degrees by walking an >> inexpensive handheld GPS over a baseline of 100 meters but I want to do >> better than that. For the hopefully more accurate measurement I would place >> one GPS and antenna at the microwave dish or lightwave transmitter and the >> other would be set up 100 meters away roughly in the direction one needed >> to >> beam. When a bearing was found one could either readjust the position of >> the >> remote GPS antenna to improve the accuracy or just allow for any error by >> beaming by this amount to the GPS unit. >> >> Let us ?assume that both GPS antennas are in a fixed location and the >> results can be averaged over say 30 minutes to improve the accuracy. ?I >> assume also that many of the errors due to propagation would cancel over >> such a short path. ?The data from both GPSs would be fed to a laptop over >> say RS232 line which I hope would work for 100 meters (perhaps 50 meters >> each way if necessary). ?The Laptop would have software to process that >> data >> and provide a bearing between the two antennas. Can anyone comment on: >> >> (a) the likely accuracy of such a system >> (b) whether there is any software out there that can do this. >> (c) the recommended GPS units for this application. >> (d) whether there is something one could purchase as a complete package at >> a >> reasonable cost (ie less than $2k) >> >> 73 Rex VK7MO >> >> >> >> >> >> -----Original Message----- >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On >> Behalf Of iovane at inwind.it >> Sent: Monday, 23 November 2009 8:08 AM >> To: time-nuts >> Subject: Re: [time-nuts] OT - GPS and North >> >> ?Thanks all. >> >> The conclusion seems to be that an ordinary and stationary GPS receiver >> with >> a single >> omnidiretional antenna knows very well where satellites are relative to the >> true North, >> and where the true North is relative to satellites, but doesn't know (more >> precisely: >> can't indicate, as it lacks another reference) where satellites or the >> North >> actually are. >> Eventually this appears quite obvious. >> >> Antonio I8IOV >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- --Eric _________________________________________ Eric Garner From billj at ieee.org Mon Nov 23 17:39:59 2009 From: billj at ieee.org (Bill Janssen) Date: Mon, 23 Nov 2009 09:39:59 -0800 Subject: [time-nuts] backup to GPS after jan 2010, was: OT - GPS and North In-Reply-To: <20091122232442.37D8EBCFC@ip-64-139-1-69.sjc.megapath.net> References: <20091122232442.37D8EBCFC@ip-64-139-1-69.sjc.megapath.net> Message-ID: <4B0AC8EF.206@ieee.org> Hal Murray wrote: > stanley_reynolds at yahoo.com said: > >> Further if at least one cell site has a accurate clock how far could >> it be repeated before it lost it's useful accuracy using the CDMA >> signal as in : >> > > I think there are two cases. > > The first is if the GPS receiver on a single site breaks, I think it would be > reasonable to have that site lock on to it's neighbors. > > The second case is when GPS dies so that all CMDA sites need to coordinate > time without help from GPS. Chains of PLLs are tricky. If they didn't need > GPS they probably wouldn't have used it to begin with. > > I think you could do it if each site had a rubidium or something that was > stable enough. I don't know what "enough" means. I think the key idea is > something like the time constants for distributing the information have to be > much faster than the time constant for tweaking the local clock. That is all > the sites have to agree on what to do and understand where they fit into the > plan. > > Early SONET ran into troubles with chains of PLLs. I forget the details if I ever knew them. I think they got the time constants wrong and ended up amplifying noise in a certain band rather than filtering it out. > > > If you told me the stability of the local clock and the round trip times to adjacent cells and how much bandwidth I could use and such, I could probably come up with a stable algorithm and tell you how far and/or how many hops it would work over. > > > I think that the site to site communications are via digital systems. All digital systems I know of use buffers on the transmitting end and on the receiving end. So the time delay between sites can vary depending on the buffer fill. The average frequency is controlled to tight limits but the time delay can vary. So time transfer is not feasible without doing a delay measurement which takes cooperation between the sites. Bill K7NOM From mspencer12345 at yahoo.ca Mon Nov 23 17:51:27 2009 From: mspencer12345 at yahoo.ca (Mark Spencer) Date: Mon, 23 Nov 2009 09:51:27 -0800 (PST) Subject: [time-nuts] Alternate frequency sources - second opinions In-Reply-To: References: <20091123000024.EA60CBCFC@ip-64-139-1-69.sjc.megapath.net> <005c01ca6bd8$fe06d8d0$0900a8c0@lark> Message-ID: <111981.87218.qm@web38803.mail.mud.yahoo.com> With regards to using WWV as a frequency source you need to watch out for the?doppler shift of sky wave signals which can be a few hz or so. This doccument has some more info re this. http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA284610&Location=U2&doc=GetTRDoc.pdf ----- Original Message ---- From: Bill Hawkins To: Discussion of precise time and frequency measurement Sent: Sun, November 22, 2009 5:32:56 PM Subject: Re: [time-nuts] Alternate frequency sources - second opinions IIRC, NTP turns a computer clock into a DO with millisecond accuracy. Accuracy is stratified, with a number of Stratum 1 sources available. Don't know if anyone has designed a collection of differentiated silicon and stored programs that hooks to the internet and delivers a disciplined 10 MHz at 50 ohms. Probably not, since even crystal oscillators do better than NTP. Beat one against WWV and you were good to 10-7 or so. Mills was working on microsecond accuracy five years ago. Where does NTP stand now? Bill Hawkins _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __________________________________________________________________ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now http://ca.toolbar.yahoo.com. From geoff at palaemon.demon.co.uk Mon Nov 23 18:21:26 2009 From: geoff at palaemon.demon.co.uk (Geoff Blake) Date: Mon, 23 Nov 2009 18:21:26 +0000 (GMT) Subject: [time-nuts] OT North (Geoff Blake) In-Reply-To: References: Message-ID: > > Didn't the moss grow on the North facing, cool side? Yes, but you only learnt that in Scouts, Sea Scouts had problems with trees, so they used Polaris to determine North. :-) Geoff -- Geoff Blake G8GNZ located near Chelmsford, Essex, U.K. Please reply to: geoff(at)palaemon(dot)demon(dot)co(dot)uk Using Linux on Intel & Linux or NetBSD on Sun Sparc platforms Please avoid sending me Word or PowerPoint attachments. See ----------------------------------------------------------------- This E-mail and any attachment(s) are strictly confidential and is intended solely for the addressee(s). If you are not the intended recipient please notify and the sender by return and permanently delete the message. You may not disclose, forward or copy this E-mail or any of its attachments to any third party without the prior consent of the sender. ---------------------------------------------------------------- From Murray.Greenman at rakon.com Mon Nov 23 18:52:26 2009 From: Murray.Greenman at rakon.com (Murray Greenman) Date: Tue, 24 Nov 2009 07:52:26 +1300 Subject: [time-nuts] EROS Oscillators In-Reply-To: References: Message-ID: EROS is an abbreviation used by the Electronic Research Company. They used to be in Overland Park, KS, USA. They made OCXOs for government and space applications. I have some of their 5MHz devices which were widely used in Transit (pre-GPS) satellite navigation receivers. These OCXOs were fixed (mechanically adjustable) but had very low ageing. The ERC OCXOs typically had "EROS" part numbers. I guess it stands for Electronic Research OScillator? I think the company is now known as Inficon - see http://www.electrodynamics.com/ 73, Murray ZL1BPU From holrum at hotmail.com Mon Nov 23 18:57:13 2009 From: holrum at hotmail.com (Mark Sims) Date: Mon, 23 Nov 2009 18:57:13 +0000 Subject: [time-nuts] AMU vs dBc In-Reply-To: References: Message-ID: A little testing shows: 2 AMU = 33 dBc 4 AMU = 36 dBc 5 AMU = 39 dBc 6 AMU = 41 dBc 9 AMU = 45 dBc 12 AMU = 47 dBc 15 AMU = 49 dBc Numbers are approximate due to shifting values and delays when switching units. _________________________________________________________________ Windows 7: It works the way you want. Learn more. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen:112009v2 From cdelect at juno.com Mon Nov 23 19:10:57 2009 From: cdelect at juno.com (Corby Dawson) Date: Mon, 23 Nov 2009 11:10:57 -0800 Subject: [time-nuts] FTS oscillator on eBay Message-ID: <20091123.111057.4076.1.cdelect@juno.com> Hi, I just posted a very nice FTS oscillator on eBay. 320453093813 It's an FTS 9110/120, take a look. Corby Dawson ____________________________________________________________ Weight Loss Program Best Weight Loss Program - Click Here! http://thirdpartyoffers.juno.com/TGL2141/c?cp=f9ihI0gpMIUCK-wq0sQrvQAAJ1ABLZFyqoH-WnHH1GJ345whAAYAAAAAAAAAAAAAAAAAAADNAAAAAAAAAAAAAAAAAAAEUgAAAAA= From maferra at gmx.com Mon Nov 23 19:18:59 2009 From: maferra at gmx.com (Marco A. Ferra) Date: Mon, 23 Nov 2009 19:18:59 -0000 Subject: [time-nuts] Rubidium standard In-Reply-To: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> References: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> Message-ID: >I was told by a Technical Support Engineer from Symmetricom Global Services >that > "The typical life span is ~10 years for these Rubidium Time Bases". > > This is in response to my request for information on a Ball/Efratom > PTB-100. > > Is this a typical life span of a rubidium standard? We had a guy from Pendulum Instruments in our Laboratory that stated that the life span of Rubidium crystals are between 10 ~ 12 years, so the information seems to be correct. I believe that when the rubidium starts to get older, it loses stability and inversely behaves like the quartz (when older, the more stable). Kind regards, > > Do some standards last longer than others? > > What are the symptoms of a failing rubidium bulb? > > Thanks > 73 > Glenn > WB4UIV From SAIDJACK at aol.com Mon Nov 23 19:21:35 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Mon, 23 Nov 2009 14:21:35 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: Hi Warren, that is correct, I care to make best use of the environment I have, not the one I would like to have (sounds like Rumsfeld, doesn't it?!). It works now with the AMU changes, and I did change the TC to 500 as well. I am comparing against my PRS-10 Rubidium (driven by an M12+ receiver) and phase-measured on my 5370B. Will post a drift plot sometime later today. bye, Said In a message dated 11/22/2009 23:10:53 Pacific Standard Time, warrensjmail-one at yahoo.com writes: Said's situation: 2) How to make the Tbolt work the best that it can with a less than optimized existing setup. Answer: Lower the AMU to 1, rise the elevation to 15or20, increase the TC setting to 500 sec. (It will work better than when the factory defaults are use with the #1 case above) From phk at phk.freebsd.dk Mon Nov 23 20:24:03 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 23 Nov 2009 20:24:03 +0000 Subject: [time-nuts] Rubidium standard In-Reply-To: Your message of "Mon, 23 Nov 2009 19:18:59 GMT." Message-ID: <41456.1259007843@critter.freebsd.dk> In message , "Marco A. Ferra" writes : >We had a guy from Pendulum Instruments in our Laboratory that stated that >the life span of Rubidium crystals are between 10 ~ 12 years, so the >information seems to be correct. I believe that when the rubidium starts to >get older, it loses stability and inversely behaves like the quartz (when >older, the more stable). There are no "rubidium crystals" involved. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From warrensjmail-one at yahoo.com Mon Nov 23 20:33:16 2009 From: warrensjmail-one at yahoo.com (WarrenS) Date: Mon, 23 Nov 2009 12:33:16 -0800 Subject: [time-nuts] Thunderbolt reception problems Message-ID: <1BA588C639BE4B649D8E495CA438DF63@WSOffice> Said I know this is not something that you really want to have to fiddle with, but you may find some of it useful information. More Default changes you may want to consider are: With the default Dac Voltage setting of 0 and the Default Survey setting of DO NOT save position If the power fails, then things have to start all over which can take a ling time. Solution: sorry I do not remember the exact names that tbolt monitor uses, but I think you can get the idea of what is needed from: 1) save the default startup Dac voltage using the current Dac voltage reading. 2) Save the current location (may have to manually copy it, don't remember) OR do a re-survey with the 'save survey location to eeprom' flag set. That and the other default changes you have made Now ALMOST make it a plug and play. Unfortunately still without an sink indicating Led, But With these setting I have never seen mine loose sink or go into holdover unless the power went off or I disconnected the antenna. And then if you really want to make it better, when comparing Phase to your PRS-10, There are other default setting that you can change that will improve it from two to ten times. Without going into the details, the most important are: 1) Let it age a month, 2) ReSet the Dac gain, default is -5Hz/volt mine measured around -3/volt 3) Set the damping, default is 1.2, 0.707 works better , Then set TC to 750 sec 4) Don't let the Temperature change fast (or at all), I'm using an active temperature controller, But a big passive 'brick thing' will help. 5) insure the + 12 power supply is real good and does not change or have noise on it. have fun ws ******************* Hi Warren, that is correct, I care to make best use of the environment I have, not the one I would like to have (sounds like Rumsfeld, doesn't it?!). It works now with the AMU changes, and I did change the TC to 500 as well. I am comparing against my PRS-10 Rubidium (driven by an M12+ receiver) and phase-measured on my 5370B. Will post a drift plot sometime later today. bye, Said *************** In a message dated 11/22/2009 23:10:53 Pacific Standard Time, warrensjmail-one at yahoo.com writes: Said's situation: 2) How to make the Tbolt work the best that it can with a less than optimized existing setup. Answer: Lower the AMU to 1, rise the elevation to 15or20, increase the TC setting to 500 sec. (It will work better than when the factory defaults are use with the #1 case above) From bg at lysator.liu.se Mon Nov 23 21:04:56 2009 From: bg at lysator.liu.se (bg at lysator.liu.se) Date: Mon, 23 Nov 2009 22:04:56 +0100 (CET) Subject: [time-nuts] FTS oscillator on eBay In-Reply-To: <20091123.111057.4076.1.cdelect@juno.com> References: <20091123.111057.4076.1.cdelect@juno.com> Message-ID: <54418.87.227.52.225.1259010296.squirrel@webmail.lysator.liu.se> Hi Corby, That IS a nice looking oscillator. Have not seen actual units with accelerometers before. Do you have more information on the accelerometer-system? is it a single/dual/triple axis system, what brand/model of accelerometer? -- Bj?rn > Hi, > > I just posted a very nice FTS oscillator on eBay. 320453093813 > It's an FTS 9110/120, take a look. > > Corby Dawson > ____________________________________________________________ > Weight Loss Program > Best Weight Loss Program - Click Here! > http://thirdpartyoffers.juno.com/TGL2141/c?cp=f9ihI0gpMIUCK-wq0sQrvQAAJ1ABLZFyqoH-WnHH1GJ345whAAYAAAAAAAAAAAAAAAAAAADNAAAAAAAAAAAAAAAAAAAEUgAAAAA= > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From mikes at flatsurface.com Mon Nov 23 21:10:40 2009 From: mikes at flatsurface.com (Mike S) Date: Mon, 23 Nov 2009 16:10:40 -0500 Subject: [time-nuts] Rubidium standard In-Reply-To: <41456.1259007843@critter.freebsd.dk> References: <41456.1259007843@critter.freebsd.dk> Message-ID: <20091123211128.3DBA11165C1@hamburg.alientech.net> At 03:24 PM 11/23/2009, Poul-Henning Kamp wrote... >There are no "rubidium crystals" involved. Next you'll try and tell us that you can't make a clock run backwards by using dilithium crystals, and making it warp time. My understanding is that the Rb gets absorbed into the glass envelope, so that eventually there isn't enough to provide proper operation. Rb isn't that expensive (you can buy 1 g for $100 at retail - http://elementsales.com/pl_element_grp1.htm ), so I'm not clear on why they don't just put more than ~0.001 g in to begin with. www.spectratime.com/product_downloads/life_mtbf.pdf From magnus at rubidium.dyndns.org Mon Nov 23 21:13:05 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Mon, 23 Nov 2009 22:13:05 +0100 Subject: [time-nuts] AMU vs dBc In-Reply-To: References: Message-ID: <4B0AFAE1.8030704@rubidium.dyndns.org> Mark Sims wrote: > A little testing shows: > 2 AMU = 33 dBc > 4 AMU = 36 dBc > 5 AMU = 39 dBc > 6 AMU = 41 dBc > 9 AMU = 45 dBc > 12 AMU = 47 dBc > 15 AMU = 49 dBc > > Numbers are approximate due to shifting values and delays when switching units. A quick play with Gnumerics gave me the formula dBc = 20*log10(AMU)+25,5 to have the best match, and RMS error of 2,23 where as the dBc = AMU + 33,9 has the RMS error of 4,34. Both offset coefficients is for lowest RMS error. A few more pairs would help to improve the estimate. Cheers, Magnus From tvb at LeapSecond.com Mon Nov 23 22:05:24 2009 From: tvb at LeapSecond.com (Tom Van Baak) Date: Mon, 23 Nov 2009 14:05:24 -0800 Subject: [time-nuts] AMU vs dBc References: <4B0AFAE1.8030704@rubidium.dyndns.org> Message-ID: <884A9EA75A704726A2275CEAFD0B02F0@pc52> > A quick play with Gnumerics gave me the formula dBc = 20*log10(AMU)+25,5 > to have the best match, and RMS error of 2,23 where as the dBc = AMU + > 33,9 has the RMS error of 4,34. AMU Arbitrary Manufacturer Units Antenna Measurement Units Arbitrary Mystery Units See if these help your estimate: http://gauss.gge.unb.ca/papers.pdf/SNR.memo.pdf ftp://goes.gsfc.nasa.gov/pub/chesters/goesref/Moreau_GPS.pdf http://www.wavedigm.com/pdf/UG_smartGPS.pdf /tvb From warrensjmail-one at yahoo.com Mon Nov 23 22:16:57 2009 From: warrensjmail-one at yahoo.com (WarrenS) Date: Mon, 23 Nov 2009 14:16:57 -0800 Subject: [time-nuts] AMU vs dBc References: Message-ID: <34EE356F40074CAE953ED436FB55708A@WSOffice> Mark Great info Can you also see what 0.0, 0.5, 1.0, 1.5, 2.5, 3.0 are equal to. Those are the important ones when setting the AMU lower. AND better estimate what the hysteresis is at each setting, It is about two or three dBc units ws *************** ----- Original Message ----- From: "Mark Sims" To: Sent: Monday, November 23, 2009 10:57 AM Subject: [time-nuts] AMU vs dBc A little testing shows: 2 AMU = 33 dBc 4 AMU = 36 dBc 5 AMU = 39 dBc 6 AMU = 41 dBc 9 AMU = 45 dBc 12 AMU = 47 dBc 15 AMU = 49 dBc Numbers are approximate due to shifting values and delays when switching units. _________________________________________________________________ Windows 7: It works the way you want. Learn more. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen:112009v2 From alan.melia at btinternet.com Mon Nov 23 22:23:36 2009 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 23 Nov 2009 22:23:36 -0000 Subject: [time-nuts] Rubidium standard References: <41456.1259007843@critter.freebsd.dk> <20091123211128.3DBA11165C1@hamburg.alientech.net> Message-ID: <002c01ca6c8c$2461c950$0900a8c0@lark> They probably dont want the little rascals bumping into one-another and broadening the resonance line :-)) Alan G3NYK ----- Original Message ----- From: "Mike S" To: "Discussion of precise time and frequency measurement" Sent: Monday, November 23, 2009 9:10 PM Subject: Re: [time-nuts] Rubidium standard > At 03:24 PM 11/23/2009, Poul-Henning Kamp wrote... > > >There are no "rubidium crystals" involved. > > Next you'll try and tell us that you can't make a clock run backwards > by using dilithium crystals, and making it warp time. > > My understanding is that the Rb gets absorbed into the glass envelope, > so that eventually there isn't enough to provide proper operation. Rb > isn't that expensive (you can buy 1 g for $100 at retail - > http://elementsales.com/pl_element_grp1.htm ), so I'm not clear on why > they don't just put more than ~0.001 g in to begin with. > > www.spectratime.com/product_downloads/life_mtbf.pdf > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From cfharris at erols.com Mon Nov 23 22:34:20 2009 From: cfharris at erols.com (Chuck Harris) Date: Mon, 23 Nov 2009 17:34:20 -0500 Subject: [time-nuts] Rubidium standard In-Reply-To: References: <6.2.3.4.2.20091112004006.059804a0@mail.bellsouth.net> Message-ID: <4B0B0DEC.80301@erols.com> Rubidium crystals?? Do tell! -Chuck Harris Marco A. Ferra wrote: >> I was told by a Technical Support Engineer from Symmetricom Global >> Services that >> "The typical life span is ~10 years for these Rubidium Time Bases". >> >> This is in response to my request for information on a Ball/Efratom >> PTB-100. >> >> Is this a typical life span of a rubidium standard? > > We had a guy from Pendulum Instruments in our Laboratory that stated > that the life span of Rubidium crystals are between 10 ~ 12 years, so > the information seems to be correct. I believe that when the rubidium > starts to get older, it loses stability and inversely behaves like the > quartz (when older, the more stable). > > Kind regards, > >> >> Do some standards last longer than others? >> >> What are the symptoms of a failing rubidium bulb? >> >> Thanks >> 73 >> Glenn >> WB4UIV > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From bruce.griffiths at xtra.co.nz Mon Nov 23 22:38:14 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 24 Nov 2009 11:38:14 +1300 Subject: [time-nuts] Rubidium standard In-Reply-To: <002c01ca6c8c$2461c950$0900a8c0@lark> References: <41456.1259007843@critter.freebsd.dk> <20091123211128.3DBA11165C1@hamburg.alientech.net> <002c01ca6c8c$2461c950$0900a8c0@lark> Message-ID: <4B0B0ED6.3080100@xtra.co.nz> Both the lamp and the absorption cell contain rubidium. The rubidium in the lamp is slowly absorbed by the glass container. The rubidim in the absorption cell is mixed with a buffer gas and presumably has a much lower rate of absorption by the cell walls. The rubidium lamp becomes unusable due to rubidium absorption long before the absorption cell rubidium is depleted. This lamp wear out mechanism is avoided if one uses laser interrogation of the absorption cell. Bruce Alan Melia wrote: > They probably dont want the little rascals bumping into one-another and > broadening > the resonance line :-)) > Alan G3NYK > ----- Original Message ----- > From: "Mike S" > To: "Discussion of precise time and frequency measurement" > > Sent: Monday, November 23, 2009 9:10 PM > Subject: Re: [time-nuts] Rubidium standard > > > >> At 03:24 PM 11/23/2009, Poul-Henning Kamp wrote... >> >> >>> There are no "rubidium crystals" involved. >>> >> Next you'll try and tell us that you can't make a clock run backwards >> by using dilithium crystals, and making it warp time. >> >> My understanding is that the Rb gets absorbed into the glass envelope, >> so that eventually there isn't enough to provide proper operation. Rb >> isn't that expensive (you can buy 1 g for $100 at retail - >> http://elementsales.com/pl_element_grp1.htm ), so I'm not clear on why >> they don't just put more than ~0.001 g in to begin with. >> >> www.spectratime.com/product_downloads/life_mtbf.pdf >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts at febo.com >> To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From phk at phk.freebsd.dk Mon Nov 23 22:47:44 2009 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 23 Nov 2009 22:47:44 +0000 Subject: [time-nuts] Rubidium standard In-Reply-To: Your message of "Tue, 24 Nov 2009 11:38:14 +1300." <4B0B0ED6.3080100@xtra.co.nz> Message-ID: <41936.1259016464@critter.freebsd.dk> In message <4B0B0ED6.3080100 at xtra.co.nz>, Bruce Griffiths writes: >This lamp wear out mechanism is avoided if one uses laser interrogation >of the absorption cell. About that... Isn't that the sort of experiement we should try to lure Tom into doing ? There must be a way to create a DIY conversion of old Rb's to laser... Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk at FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. From didier at cox.net Mon Nov 23 22:58:53 2009 From: didier at cox.net (Didier Juges) Date: Mon, 23 Nov 2009 22:58:53 +0000 Subject: [time-nuts] AMU vs dBc Message-ID: <756909222-1259017128-cardhu_decombobulator_blackberry.rim.net-85689365-@bda224.bisx.prod.on.blackberry> How about Arithmetically Meaningless Units? Didier ------Original Message------ From: Tom Van Baak Sender: time-nuts-bounces at febo.com To: Time-Nuts ReplyTo: Tom Van Baak ReplyTo: Time-Nuts Subject: Re: [time-nuts] AMU vs dBc Sent: Nov 23, 2009 4:05 PM > A quick play with Gnumerics gave me the formula dBc = 20*log10(AMU)+25,5 > to have the best match, and RMS error of 2,23 where as the dBc = AMU + > 33,9 has the RMS error of 4,34. AMU Arbitrary Manufacturer Units Antenna Measurement Units Arbitrary Mystery Units See if these help your estimate: http://gauss.gge.unb.ca/papers.pdf/SNR.memo.pdf ftp://goes.gsfc.nasa.gov/pub/chesters/goesref/Moreau_GPS.pdf http://www.wavedigm.com/pdf/UG_smartGPS.pdf /tvb _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ------------------------ Sent from my BlackBerry Wireless thingy while I do other things... From bruce.griffiths at xtra.co.nz Mon Nov 23 22:59:14 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 24 Nov 2009 11:59:14 +1300 Subject: [time-nuts] Rubidium standard In-Reply-To: <41936.1259016464@critter.freebsd.dk> References: <41936.1259016464@critter.freebsd.dk> Message-ID: <4B0B13C2.1010807@xtra.co.nz> Poul-Henning Kamp wrote: > In message<4B0B0ED6.3080100 at xtra.co.nz>, Bruce Griffiths writes: > > >> This lamp wear out mechanism is avoided if one uses laser interrogation >> of the absorption cell. >> > About that... > > Isn't that the sort of experiement we should try to lure Tom into doing ? > > There must be a way to create a DIY conversion of old Rb's to laser... > > Poul-Henning > > As in: http://tf.nist.gov/timefreq/general/pdf/2232.pdf Which uses injection locking to avoid generating the 6.834...GHz signal directly Bruce From kScally at BYTECAN.com.au Mon Nov 23 23:30:42 2009 From: kScally at BYTECAN.com.au (Kit Scally) Date: Tue, 24 Nov 2009 10:30:42 +1100 Subject: [time-nuts] Alternate frequency sources : DVB-T and ISDN & OT comment In-Reply-To: References: Message-ID: <281090D5003763419A5AC496FF087B2A83F036@msg01nsw.BYTECAN.com.au> Guys, Don't get confused with (a) recovering the transmitter's carrier frequency and (b) recovering the colour burst and/or data stream in a DVB-T signal for use as a "house frequency standard". They're not one of the same ! Most TV carrier frequencies here in Sydney, Aust (analogue & digital - we've got both running at the present time) are bog-standard xtals (possibly ovened). As noted by others, this crude approach isn't good enough for SFN's Attempting to recover any part of a RAW MPEG data stream from a "$49 digital STB" may be doomed to failure. Most STB of this ilk use a single jungle-chip with RF in and various flavours of video out. The data streams you need to access for any clock recovery strategy is unfortunately buried in silicon.... OT - Happy Thanksgiving holiday to all those in the USA & Canada. Kit VK2LL Sydney Christian Vogel wrote: > Hi Alan, > > at least here in Germany the digital TV transmissions (DVB-T) are > using (in some areas) Single Frequency Networks[1]. I live near one of > the transmitters and when I visited the facility, they had Meinberg > GPS receivers in the racks housing the TV signal generators. SFN requires synchronisation of frequency (10 MHz) and phase (PPS). DVB-T transmitters using SFN will broadcast pilot-tones. See ETSI EN 300 744, accessable through: http://www.dvb.org/technology/standards/ >>snip From Arnold.Tibus at gmx.de Mon Nov 23 23:33:52 2009 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Tue, 24 Nov 2009 00:33:52 +0100 Subject: [time-nuts] AMU vs dBc In-Reply-To: <756909222-1259017128-cardhu_decombobulator_blackberry.rim.net-85689365-@bda224.bisx.prod.on.blackberry> Message-ID: Hi everybody, in a document from Trimble (TTM637VME/TTM357VXI GPS Satellite Receiver Addendum, User's Guide) I found: "The signal level (Byte 5) is a linear approximation of C/N0 which is stated in antenna amplitude measurement units (AMUs), a Trimble devised unit. An approximate correlation of AMU levels to C/N0 follows: 5 AMUs -20 dB SNR 16 AMUs -10 dB SNR or AMUs 51 * 26 AMUs -5 dB SNR The C/N0 is affected by five basic parameters: 1. Signal strength from the GPS satellite. 2. Receiver/antenna gain. 3. Pre-amplifier noise figure. 4. Receiver noise bandwidth. 5. Accumulator sample rate and statistics. The approximation is very accurate from 0 to 25 AMUs" In TBoltMon under 'Packet Masks and Options'/ 'Aux Byte (3)'/ 'Output dBc/Hz' you can set what kind of readout you want to see under 'AMU' I have it set always to 'dBc/Hz and most of the Satellites are coming in with up to 45 dBc/Hz. A quick check (not easy because these beasts dont stop moving ;-) ) gives about the following values in AMU / dBc/Hz: 2 / 29 5 / 36 5.5 / 39 6.2 / 40 7 / 41 9 / 43 10 / 44 11 / 45 good luck, cheers Arnold On Mon, 23 Nov 2009 22:58:53 +0000, Didier Juges wrote: >How about Arithmetically Meaningless Units? >Didier >------Original Message------ >From: Tom Van Baak >Sender: time-nuts-bounces at febo.com >To: Time-Nuts >ReplyTo: Tom Van Baak >ReplyTo: Time-Nuts >Subject: Re: [time-nuts] AMU vs dBc >Sent: Nov 23, 2009 4:05 PM >> A quick play with Gnumerics gave me the formula dBc = 20*log10(AMU)+25,5 >> to have the best match, and RMS error of 2,23 where as the dBc = AMU + >> 33,9 has the RMS error of 4,34. >AMU >Arbitrary Manufacturer Units >Antenna Measurement Units >Arbitrary Mystery Units >See if these help your estimate: >http://gauss.gge.unb.ca/papers.pdf/SNR.memo.pdf >ftp://goes.gsfc.nasa.gov/pub/chesters/goesref/Moreau_GPS.pdf >http://www.wavedigm.com/pdf/UG_smartGPS.pdf >/tvb >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. >------------------------ Sent from my BlackBerry Wireless thingy while I do other things... >_______________________________________________ >time-nuts mailing list -- time-nuts at febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. From SAIDJACK at aol.com Mon Nov 23 23:39:16 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Mon, 23 Nov 2009 18:39:16 EST Subject: [time-nuts] Alternate frequency sources : DVB-T and ISDN & OT comment Message-ID: Hi Kit, there is an easy way out: Use a Philips Video Decoder (SAA7113 or similar), it will generate a locked 27MHz output reference pixel clock from the video stream coming out of the STB. Unfortunately most $49 STB's don't do proper PCR synchronization via PLL, they just do dropped frames, or repeated frames... bye, Said In a message dated 11/23/2009 15:32:47 Pacific Standard Time, kScally at BYTECAN.com.au writes: Attempting to recover any part of a RAW MPEG data stream from a "$49 digital STB" may be doomed to failure. Most STB of this ilk use a single jungle-chip with RF in and various flavours of video out. The data streams you need to access for any clock recovery strategy is unfortunately buried in silicon.... From kyrrin at bluefeathertech.com Mon Nov 23 23:39:02 2009 From: kyrrin at bluefeathertech.com (Bruce Lane) Date: Mon, 23 Nov 2009 15:39:02 -0800 Subject: [time-nuts] Rubidium Crystals? Message-ID: <200911231539020031.0188700C@192.168.42.129> "We've secretly replaced the Rubidium Crystals in this physics lab break-room with Folger's Crystals -- let's see if anyone can tell the difference!" (No need to get violent, I'll go quietly...) ;-) Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies (http://www.bluefeathertech.com) Assoc. member, IMATA, AZA & AAZK for many moons. "Salvadore Dali's computer has surreal ports..." From jgray at zianet.com Mon Nov 23 23:55:05 2009 From: jgray at zianet.com (Joseph Gray) Date: Mon, 23 Nov 2009 16:55:05 -0700 Subject: [time-nuts] Rubidium Crystals? In-Reply-To: <200911231539020031.0188700C@192.168.42.129> References: <200911231539020031.0188700C@192.168.42.129> Message-ID: I'll admit - I chuckled. I guess we're all showing our age if we remember that commercial. Joe Gray KA5ZEC On Mon, Nov 23, 2009 at 4:39 PM, Bruce Lane wrote: > ? ? ? ?"We've secretly replaced the Rubidium Crystals in this physics lab > break-room with Folger's Crystals -- let's see if anyone can tell the > difference!" > > ? ? ? ?(No need to get violent, I'll go quietly...) ;-) > > > Bruce Lane, Owner & Head Hardware Heavy, > Blue Feather Technologies > (http://www.bluefeathertech.com) > Assoc. member, IMATA, AZA & AAZK for many moons. > "Salvadore Dali's computer has surreal ports..." > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > From magnus at rubidium.dyndns.org Tue Nov 24 00:06:24 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 24 Nov 2009 01:06:24 +0100 Subject: [time-nuts] Thunderbolt reception problems In-Reply-To: References: <5C5D0692C552490E8FDA7FB1BF0D153E@WSOffice> <4B09DF6D.7010107@rubidium.dyndns.org> Message-ID: <4B0B2380.2090101@rubidium.dyndns.org> WarrenS wrote: > Some of the disagreement has to do with the fact that Two similar topics, each with a different answer are being mixed together here. > > Magnus's point: > 1) How to make the Tbolt the best that it can be? > Answer: Start with a good strong signal and a quiet environment. Actually, that was not my point. My point was that the signal levels is lower than what is the normally recommended level and worse performance may be expected otherwise. > Said's situation: > 2) How to make the Tbolt work the best that it can with a less than optimized existing setup. > Answer: Lower the AMU to 1, rise the elevation to 15or20, increase the TC setting to 500 sec. > (It will work better than when the factory defaults are use with the #1 case above) I rather viewed it as, when things isn't as optimal... lower the level to get more sats to play with and thus a more stable situation. These things isn't really in conflict... one is being aware that you left stable ground and the other is how to best handle that situation. > Interesting enough, I have both cases with optimized setting running on my bench now and although the #1 is generally about 25% to 50% quieter, > It is not always so. About 25% of the time the #2 case is as quiet or quieter. So the less than perfect #2 case is not really a big deal to most. > There are much more important things that can be done if one likes to 'tweak & fiddle'. Lowering the AMU limit would hopefully get sufficient sats in place, but it can be used to find a balance so that the effective constallation doesn't change, so weak potential dropouts can be cleared off while many reliable (altought maybe just a thad weak) remain in the solution. The AMU limit is a two-edged sword... at least. I was trying to warn about the fact that you now accept lower power signals, and is not just a magical twist of knobs that makes everything good again. There is a benefit in lowering that limit given the situation, and I happilly agree with that. > concerning: >> that you may not get the performance of the spec-sheet. > Not a problem, cause they seem careful not to include any specs concerning this except for the 1e-12 per day average. TvBs measurements could be another source... it's just so you know that beyond that point your milage may vary... Cheers, Magnus From magnus at rubidium.dyndns.org Tue Nov 24 00:53:26 2009 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 24 Nov 2009 01:53:26 +0100 Subject: [time-nuts] Rubidium Crystals? In-Reply-To: <200911231539020031.0188700C@192.168.42.129> References: <200911231539020031.0188700C@192.168.42.129> Message-ID: <4B0B2E86.7020705@rubidium.dyndns.org> Bruce Lane wrote: > "We've secretly replaced the Rubidium Crystals in this physics lab > break-room with Folger's Crystals -- let's see if anyone can tell the > difference!" > > (No need to get violent, I'll go quietly...) ;-) I'll badly need some caesium-crystals in my cup of java after that... nothing like that sparkling and fizzing sound as I pop them in... watching them melt... Cheers, Magnus - had to look things up... From SAIDJACK at aol.com Tue Nov 24 01:52:03 2009 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Mon, 23 Nov 2009 20:52:03 EST Subject: [time-nuts] Thunderbolt reception problems Message-ID: Hi Warren, et. al, here is a plot (about 20hrs long) of my PRS-10 (driven by a M12+) compared against my Thunderbolt both running from the same antenna feed. Comparison done on the 10MHz outputs, at maximum sample rate on my 5370B counter. Both units have been running for 6+ months now, the Thunderbolt has only been locked for a day+ though. Standard deviation is 7.6ns, and the mean is 1.5ns. Peak to Peak is ~ -15ns to +19ns. I was hoping for slightly better. Not sure who is the better of the two (yet). Bye, Said In a message dated 11/23/2009 11:22:27 Pacific Standard Time, SAIDJACK at aol.com writes: Will post a drift plot sometime later today. bye, Said -------------- next part -------------- A non-text attachment was scrubbed... Name: PRS-10_Thunderbolt.gif Type: image/gif Size: 37325 bytes Desc: not available URL: From rputz at bnin.net Tue Nov 24 02:09:29 2009 From: rputz at bnin.net (Rich and Marcia Putz) Date: Mon, 23 Nov 2009 21:09:29 -0500 Subject: [time-nuts] T-Bolt MonitorDocumentation Message-ID: <002401ca6cab$2fc30d80$6400a8c0@newiw112a268qp> HI All; Did I see on a post recently that there is a document for the T-Bolt Monitor program? Or was that just a figment of my imagination? Please advise/ Rich From holrum at hotmail.com Tue Nov 24 02:16:47 2009 From: holrum at hotmail.com (Mark Sims) Date: Tue, 24 Nov 2009 02:16:47 +0000 Subject: [time-nuts] AMU vs dBc In-Reply-To: References: Message-ID: Alas, there is no way to get a direct conversion between AMU and dBc. What you have to do is display the signal levels in dBc and then switch the unit to AMU. It takes it a couple of seconds before it switches. By then the signal levels have changed, so that the data is only approximate. The lower signal levels seem to change the most so I have been unable to get any reliable/repeatable readings. Even setting the AMU mask level and watching where sats turn yellow/green does not work well. There appears to be some hysterisis/filtering/delay in the selection/deselection process. ---------------- Can you also see what 0.0, 0.5, 1.0, 1.5, 2.5, 3.0 are equal to. Those are the important ones when setting the AMU lower. _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/177141665/direct/01/ From bruce.griffiths at xtra.co.nz Tue Nov 24 03:03:19 2009 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 24 Nov 2009 16:03:19 +1300 Subject: [time-nuts] Rubidium standard In-Reply-To: <4B0B13C2.1010807@xtra.co.nz> References: <41936.1259016464@critter.freebsd.dk> <4B0B13C2.1010807@xtra.co.nz> Message-ID: <4B0B4CF7.9040904@xtra.co.nz> Bruce Griffiths wrote: > Poul-Henning Kamp wrote: >> In message<4B0B0ED6.3080100 at xtra.co.nz>, Bruce Griffiths writes: >> >>> This lamp wear out mechanism is avoided if one uses laser interrogation >>> of the absorption cell. >> About that... >> >> Isn't that the sort of experiement we should try to lure Tom into >> doing ? >> >> There must be a way to create a DIY conversion of old Rb's to laser... >> >> Poul-Henning >> > As in: > http://tf.nist.gov/timefreq/general/pdf/2232.pdf > > Which uses injection locking to avoid generating the 6.834...GHz > signal directly > > Bruce Another method which may be more directly applicable when attempting to resuse some of the electronics in an rubidium standard whose rubidium lamp has failed: http://physweb.bgu.ac.il/SUBMISSIONS/PROJECTS/Liorne_Benh_2008A.pdf Note that one needs to use 2 rubidium 87 cells, one to lock the laser to the required transition, and the other to lock the microwave source to the Rb87 hyperfine transition. Also one needs to use a tunable laser (ECDL-external cavity laser). Although angle cleaved laser chips are best it is actually possible to construct a satisfactory ECDL with an inexpensive diode laser without anti-reflection coatings or angle cleaved facets. Bruce From paulswedb at gmail.com Tue Nov 24 03:09:27 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 23 Nov 2009 22:09:27 -0500 Subject: [time-nuts] Rubidium standard In-Reply-To: <20091123211128.3DBA11165C1@hamburg.alientech.net> References: <41456.1259007843@critter.freebsd.dk> <20091123211128.3DBA11165C1@hamburg.alientech.net> Message-ID: I might indeed believe the glass absorbs it. That might have been what I had seen when trying to repair some of the lpro type rbs. Thanks On Mon, Nov 23, 2009 at 4:10 PM, Mike S wrote: > At 03:24 PM 11/23/2009, Poul-Henning Kamp wrote... > > There are no "rubidium crystals" involved. >> > > Next you'll try and tell us that you can't make a clock run backwards by > using dilithium crystals, and making it warp time. > > My understanding is that the Rb gets absorbed into the glass envelope, so > that eventually there isn't enough to provide proper operation. Rb isn't > that expensive (you can buy 1 g for $100 at retail - > http://elementsales.com/pl_element_grp1.htm ), so I'm not clear on why > they don't just put more than ~0.001 g in to begin with. > > www.spectratime.com/product_downloads/life_mtbf.pdf > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From paulswedb at gmail.com Tue Nov 24 03:26:14 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 23 Nov 2009 22:26:14 -0500 Subject: [time-nuts] Alternate frequency sources : DVB-T and ISDN & OT comment In-Reply-To: <281090D5003763419A5AC496FF087B2A83F036@msg01nsw.BYTECAN.com.au> References: <281090D5003763419A5AC496FF087B2A83F036@msg01nsw.BYTECAN.com.au> Message-ID: Kit, On Mon, Nov 23, 2009 at 6:30 PM, Kit Scally wrote: > Guys, > > > Don't get confused with (a) recovering the transmitter's carrier > frequency and (b) recovering the colour burst and/or data stream in a > DVB-T signal for use as a "house frequency standard". They're not one > of the same ! > > Most TV carrier frequencies here in Sydney, Aust (analogue & digital - > we've got both running at the present time) are bog-standard xtals > (possibly ovened). As noted by others, this crude approach isn't good > enough for SFN's > > Attempting to recover any part of a RAW MPEG data stream from a "$49 > digital STB" may be doomed to failure. Most STB of this ilk use a single > jungle-chip with RF in and various flavours of video out. The data > streams you need to access for any clock recovery strategy is > unfortunately buried in silicon.... > > > OT - Happy Thanksgiving holiday to all those in the USA & Canada. > > > Kit > > VK2LL > Sydney > > Christian Vogel wrote: > > Hi Alan, > > > > at least here in Germany the digital TV transmissions (DVB-T) are > > using (in some areas) Single Frequency Networks[1]. I live near one of > > > the transmitters and when I visited the facility, they had Meinberg > > GPS receivers in the racks housing the TV signal generators. > > SFN requires synchronisation of frequency (10 MHz) and phase (PPS). > DVB-T transmitters using SFN will broadcast pilot-tones. See ETSI EN 300 > 744, accessable through: > > http://www.dvb.org/technology/standards/ > > >>snip > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > From paulswedb at gmail.com Tue Nov 24 03:30:26 2009 From: paulswedb at gmail.com (paul swed) Date: Mon, 23 Nov 2009 22:30:26 -0500 Subject: [time-nuts] Alternate frequency sources : DVB-T and ISDN & OT comment In-Reply-To: <281090D5003763419A5AC496FF087B2A83F036@msg01nsw.BYTECAN.com.au> References: <281090D5003763419A5AC496FF087B2A83F036@msg01nsw.BYTECAN.com.au> Message-ID: I hate that in google mail you can't use the tab key Lets try again. Thanks for the response. As a broadcast engineer I am familiar with the realities of the signals. Indeed you are right they get moused up pretty well. Just figure after I nail down a few projects I may dig into see what might be in the box. If a reference were available the question becomes how good is it in reality. Thats what this groups about. :-) On Mon, Nov 23, 2009 at 6:30 PM, Kit Scally wrote: > Guys, > > > Don't get confused with (a) recovering the transmitter's carrier > frequency and (b) recovering the colour burst and/or data stream in a > DVB-T signal for use as a "house frequency standard". They're not one > of the same ! > > Most TV carrier frequencies here in Sydney, Aust (analogue & digital - > we've got both running at the present time) are bog-standard xtals > (possibly ovened). As noted by others, this crude approach isn't good > enough for SFN's > > Attempting to recover any part of a RAW MPEG data stream from a "$49 > digital STB" may be doomed to failure. Most STB of this ilk use a single > jungle-chip with RF in and various flavours of video out. The data > streams you need to access for any clock recovery strategy is > unfortunately buried