From jmiles at pop.net Fri Aug 1 00:40:29 2008 From: jmiles at pop.net (John Miles) Date: Thu, 31 Jul 2008 21:40:29 -0700 Subject: [time-nuts] What is a Time-Nut grade Zero Crossing Circuit? In-Reply-To: <22592.192.25.142.225.1217552351.squirrel@webmail.sonic.net> Message-ID: > > Modern ECL parts aren't necessarily that bad compared to the old MECL > > stuff. > > My experience goes all the way back to the MECL 1000 series that was > discontinued 30 years ago. I designed many synthesizers around them > for Zeta Labs. Every newer family of ECL line receivers has been faster > and had worse phase noise, in my experience. Which is odd because the jitter specs have gotten better -- at least, going by the promises and hype in the data sheets. It sounds like the newer ECL parts' wider bandwidth is folding more noise into the output signal. > This is a very tricky topic. When measuring the phase noise of a non > sine wave, there are dependencies on how the measurement is done. > What is the measurement bandwidth? Etc. > > In some cases, the noise is mostly common mode, and therefore will > depend on the common mode rejection ratio (if any) of your measurement > circuit. I'm measuring it with a 3048A, feeding the DBM directly from one of the MC100EL16P's output pins via a 0.1 uF cap. Both output pins are tied to ground with 200 ohms, per Q12 at http://www.pulseresearchlab.com/faqs/ecl_ques/ecl_Q9-Q12.htm . Input-wise, I just tried a T1-1 balun instead of the single-ended termination I was using before, and got exactly the same results (floor at circa -148 to -150 dBc/Hz at 100 MHz, but only -140 dBc/Hz at 10 MHz.) That, I thought was interesting. -148 dBc/Hz was always the 'rule of thumb' for the older ECL families from what I've read, and since it's not sensitive to input configuration or power-supply bypassing, it must be the process floor. There was no LC or other bandpass filtering at the input, but the sources are decent-quality OCXOs in both cases so I don't think I'm feeding it too much broadband noise to begin with. Maybe another T1-1 at the output would help, but I don't see any reason to think so. -- john, KE5FX From richard at karlquist.com Fri Aug 1 01:05:43 2008 From: richard at karlquist.com (Richard (Rick) Karlquist) Date: Thu, 31 Jul 2008 22:05:43 -0700 Subject: [time-nuts] What is a Time-Nut grade Zero Crossing Circuit? In-Reply-To: References: Message-ID: <489299A7.5020903@karlquist.com> John Miles wrote: >>> Modern ECL parts aren't necessarily that bad compared to the old MECL >>> stuff. >> My experience goes all the way back to the MECL 1000 series that was >> discontinued 30 years ago. I designed many synthesizers around them >> for Zeta Labs. Every newer family of ECL line receivers has been faster >> and had worse phase noise, in my experience. > > Which is odd because the jitter specs have gotten better -- at least, going > by the promises and hype in the data sheets. It sounds like the newer ECL > parts' wider bandwidth is folding more noise into the output signal. The older parts had no jitter specs. Jitter specs assume a logic waveform input, not a sine wave input. Many jitter specs refer to pattern jitter of data, which does not apply to clocks. Also, jitter increases at low frequencies in practice, even though in theory it should not. Like I said, this topic is very tricky. Rick Karlquist N6RK > >> This is a very tricky topic. When measuring the phase noise of a non >> sine wave, there are dependencies on how the measurement is done. >> What is the measurement bandwidth? Etc. >> >> In some cases, the noise is mostly common mode, and therefore will >> depend on the common mode rejection ratio (if any) of your measurement >> circuit. > > I'm measuring it with a 3048A, feeding the DBM directly from one of the > MC100EL16P's output pins via a 0.1 uF cap. Both output pins are tied to > ground with 200 ohms, per Q12 at > http://www.pulseresearchlab.com/faqs/ecl_ques/ecl_Q9-Q12.htm . > > Input-wise, I just tried a T1-1 balun instead of the single-ended > termination I was using before, and got exactly the same results (floor at > circa -148 to -150 dBc/Hz at 100 MHz, but only -140 dBc/Hz at 10 MHz.) > That, I thought was interesting. -148 dBc/Hz was always the 'rule of thumb' > for the older ECL families from what I've read, and since it's not sensitive > to input configuration or power-supply bypassing, it must be the process > floor. I measured phase noise on an MC100E131 drop from -145 to -165 by taking the output differentially. This was done in 1992. Others have been unable to repeat this result, even using some old 1992 parts I kept. So who knows? Todd Pearson of Motorola said that they have seen this drop with differential outputs. > > There was no LC or other bandpass filtering at the input, but the sources > are decent-quality OCXOs in both cases so I don't think I'm feeding it too > much broadband noise to begin with. > > Maybe another T1-1 at the output would help, but I don't see any reason to > think so. > > -- john, KE5FX > > > > _______________________________________________ > time-nuts mailing list -- 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.paddock at gmail.com Fri Aug 1 06:32:04 2008 From: bob.paddock at gmail.com (Bob Paddock) Date: Fri, 1 Aug 2008 06:32:04 -0400 Subject: [time-nuts] What is a Time-Nut grade Zero Crossing Circuit? In-Reply-To: <489299A7.5020903@karlquist.com> References: <489299A7.5020903@karlquist.com> Message-ID: > Jitter specs assume a logic > waveform input, not a sine wave input. Many jitter specs refer to > pattern jitter of data, which does not apply to clocks. Also, jitter > increases at low frequencies in practice, even though in theory it > should not. Like I said, this topic is very tricky. How exactly does zero jitter? I understand that the logic detecting the zero voltage point of a sine wave might not be perfect. However if the circuit is truly a Zero Crossing Detector, things like the frequency and amplitude variations of the sine wave are irrelevant, as long as the bandwidth is sufficient to the design of the detector. From bruce.griffiths at xtra.co.nz Fri Aug 1 06:57:50 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 01 Aug 2008 22:57:50 +1200 Subject: [time-nuts] What is a Time-Nut grade Zero Crossing Circuit? In-Reply-To: References: <489299A7.5020903@karlquist.com> Message-ID: <4892EC2E.1040903@xtra.co.nz> Bob Paddock wrote: >> Jitter specs assume a logic >> waveform input, not a sine wave input. Many jitter specs refer to >> pattern jitter of data, which does not apply to clocks. Also, jitter >> increases at low frequencies in practice, even though in theory it >> should not. Like I said, this topic is very tricky. >> > > How exactly does zero jitter? I understand that the logic detecting > the zero voltage point of a sine wave might not be perfect. However > if the circuit is truly a Zero Crossing Detector, things like > the frequency and amplitude variations of the sine wave are irrelevant, > as long as the bandwidth is sufficient to the design of the detector. > > Real circuits have noise. Thus with a signal having a finite slew rate through the zero crossing any noise (internal or external) will cause the switching delay (from the noise free zero crossing) to differ for each zero crossing. The noise increases with circuit bandwidth increasing the noise. There is an optimum bandwidth which minimises the ratio of the noise to zero crossing slew rate and hence the jitter. Smaller or larger bandwidths increase the jitter. Sinewave amplitude variations alter the zero crossing slew rate and hence the jitter. There is a minimum input slew rate required to minimise the jitter at the output of a logic gate. When the zero crossing slew rate is less than this a slope amplifier consisting of a cascade of amplifier limiters each with a filtered output is used to amplify the slope. The gain and filter bandwidth for each stage are optimised to meet the required slope gain whilst minimising the output noise. There is also an optimum number of gain stages for minimum noise. Bruce From frankmarian at optusnet.com.au Sat Aug 2 04:48:07 2008 From: frankmarian at optusnet.com.au (frankmarian) Date: Sat, 2 Aug 2008 18:48:07 +1000 Subject: [time-nuts] PCB for frequency divider Message-ID: Hi Dave If you have any boards still available I would like to purchase one please. I live in Australia. Could you please send circuit diagram please Regards Frank From magnus at rubidium.dyndns.org Sat Aug 2 12:44:57 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 02 Aug 2008 18:44:57 +0200 Subject: [time-nuts] How to get 32.768KHz from 10MHz. In-Reply-To: <00b901c8eccd$b95782b0$7300a8c0@p4253> References: <00b901c8eccd$b95782b0$7300a8c0@p4253> Message-ID: <48948F09.9090803@rubidium.dyndns.org> Max Skop wrote: > How does one get a 32.768KHz signal from our 10MHz reference. > There does not appear to be a nice divide ratio to do this. > With a locked 32.768KHz signal one could lock the oscillator of any of the cheap (low cost) LCD clocks that are available with nice big digits, temperature sensors and calendars, etc. > Any suggestions on how to do it?? I would consider locking a 8,192 MHz crystal to the 10 MHz. The comparator frequency of 16 kHz using a division of 625 from the 10 MHz and a 512 from the 8,192 MHz oscillator. The 32,768 kHz output can be generated by first dividing by 125 and then a division by 2 for propper 50% pulse ratio. Not too complex and the comparator frequency is high enought for a nice filter should be able to do it. I would use a SR flip-flop for phase detector. For this kind of work they work very well IMHO. Cheers, Magnus From not.again at btinternet.com Sat Aug 2 16:38:14 2008 From: not.again at btinternet.com (Angus) Date: Sat, 02 Aug 2008 21:38:14 +0100 Subject: [time-nuts] LPRO 101 ADJUSTMENT In-Reply-To: <1AC9FBE457064A31938866B12D0E56F8@DESKTOP> References: <9835219326F6421AB4A20EA07D3471FD@athlon> <48876375.5060200@tiscali.co.uk> <05B23324048C4866A8B94C37A6E6BDD1@DESKTOP> <488A5E7A.6060602@intt.net> <1AC9FBE457064A31938866B12D0E56F8@DESKTOP> Message-ID: External adjustment makes it very easy to adjust as you have access to the adjustment voltage to measure it, and even a 1K multi-turn wirewound pot would give around 1E-12 setting resolution. The sensitivty of the EFC is only around 1E-12 per mV, so it is much less sensitive to temperature stability than quartz oscillators. A temperature coeff of +/- 20ppm /degC with an EFC voltage of 2.5V would only contribute around +/-5E-14 /degC frequency change. By adding fine adjustment or a DAC, you can get way below 1E-13 setting resolution. The only problem here is that environmental conditions such as variations in temperature and pressure do affect Rb oscillators and the EFC circuit, and can change the frequency by 1E-13 in a matter of minutes. Still, it's useful to be able to do it for disciplining, or if the environmental conditions are being controlled or compensated for. The ADEV of an LPRO can be around 1E-13 or so at a tau of hours, so even a step size of 1E-13 can be rather too coarse, especially if the environmental effects have been minimised. It would be nice to find a relatively simple and inexpensive 10MHz synthesizer that has a resolution of closer to 1E-14 to avoid messing with the EFC at all. Angus. On Fri, 25 Jul 2008 20:33:26 -0400, you wrote: >If I choose to control the frequency via External C-field control I guess it >would take a very precise and stable voltage source. Any thoughts or >suggestions? > >----- Original Message ----- >From: "Scott Mace" >To: "jshank" ; "Discussion of precise time and >frequency measurement" >Sent: Friday, July 25, 2008 7:15 PM >Subject: Re: [time-nuts] LPRO 101 ADJUSTMENT > > >> Both methods work well. Be sure the unit is mounted to some sort of >> heatsink,chassis, etc. >> I'm using a Fury GPS receiver to drive the EFC on an LPRO-101. >> You won't get much range out of either adjustment. Leave it powered >> on for a couple of hours before trying to adjust it. I usually set the >> trim pot in the >> middle of it's range and use the EFC pin. I think it's a 28 or 30 turn >> pot. EFC >> is 0-5v. The unit will self-bias to around 2.5v if the EFC pin is open. >> >> Scott >> >> jshank wrote: >>> Hi, >>> >>> I recently acquired a LPRO 101 Rubidium Oscillator. After reading the >>> manual I see that there are two ways to adjust the frequency 1) using and >>> adjusting screw on the unit and 2) using the External C-field control >>> signal at pin J1-7. Has anyone experimented with either method and if so >>> what method was preferred? >>> >>> Jeff >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- 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 mfeher at eozinc.com Sat Aug 2 18:59:09 2008 From: mfeher at eozinc.com (Mike Feher) Date: Sat, 2 Aug 2008 18:59:09 -0400 Subject: [time-nuts] Antikythera In-Reply-To: References: Message-ID: <013501c8f4f3$609c5eb0$0201a8c0@gsmacdq14es> FYI - Mike http://www.nature.com/nature/videoarchive/antikythera/ Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 From rogburn at warpspeed1.net Sun Aug 3 09:48:19 2008 From: rogburn at warpspeed1.net (Robert Ogburn) Date: Sun, 3 Aug 2008 08:48:19 -0500 Subject: [time-nuts] Trimble Placer GPS400 Message-ID: We have a Trimble Placer GPS400 that reports version as: SVEESIX ver 4.06 (05/18/94) core ver 1.17 (12/21/93). Is this correct? If not, how do we restore? Thanks bob From rk at timing-consultants.com Mon Aug 4 04:03:10 2008 From: rk at timing-consultants.com (Rob Kimberley) Date: Mon, 4 Aug 2008 09:03:10 +0100 Subject: [time-nuts] Trimble Placer GPS400 In-Reply-To: References: Message-ID: Bob, SVEESIX is a Trimble GPS engine. From the report, it is telling you that the model you have uses that engine with those version numbers. What are you looking to restore? Not sure I understand your problem. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Ogburn Sent: 03 August 2008 14:48 To: time-nuts at febo.com Subject: [time-nuts] Trimble Placer GPS400 We have a Trimble Placer GPS400 that reports version as: SVEESIX ver 4.06 (05/18/94) core ver 1.17 (12/21/93). Is this correct? If not, how do we restore? Thanks bob _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. From vilgotch at bigpond.net.au Mon Aug 4 04:48:27 2008 From: vilgotch at bigpond.net.au (Morris Odell) Date: Mon, 4 Aug 2008 18:48:27 +1000 Subject: [time-nuts] Antikythera References: Message-ID: <003c01c8f60e$dd2b0be0$ad00a8c0@Morris1> ----- Original Message ----- > Date: Sat, 2 Aug 2008 18:59:09 -0400 > From: "Mike Feher" > Subject: [time-nuts] Antikythera > To: "'Discussion of precise time and frequency measurement'" > > Message-ID: <013501c8f4f3$609c5eb0$0201a8c0 at gsmacdq14es> > Content-Type: text/plain; charset="US-ASCII" > > FYI - Mike > > http://www.nature.com/nature/videoarchive/antikythera/ > See: http://www.tatjavanvark.nl/antikythera/index.html and take a look at the rest of her website as well! Morris From jim77742 at gmail.com Mon Aug 4 05:47:16 2008 From: jim77742 at gmail.com (Jim Palfreyman) Date: Mon, 4 Aug 2008 19:47:16 +1000 Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser Message-ID: Hi folks, I took my recently acquired Thunderbolt, along with my 5370B, to the observatory on the weekend and plotted its residual against the NR Active Hydrogen Maser. See the attached graph (ignore the "line of best fit" heading - 0.00 was simply the starting point). Note that I didn't let the Thunderbolt do a survey, I simply plugged in the local GPS coordinates which I later verified were about 5m to the east of the actual Thunderbolt antenna. The y axis is residual in nanoseconds and the x axis is Modified Julian Date. I find the residuals fascinating. Note the identical repeating residuals in a 24 hour cycle. Is this due to thermal or constellation issues? The local GPS (not a GPSDO but an early version Totally Accurate Clock) showed a roughly (very roughly) similar pattern when averaged with 5 minute averages to hide the awful 100nsec sawtooth. The observatory is air conditioned (but with poor insulation) and has many devices constantly running. I doubt it is thermal, however the low point is at 6:30am in the morning, just before I arrived. Can anyone provide comment on this pattern? Regards, Jim -------------- next part -------------- A non-text attachment was scrubbed... Name: ThunderboltHM.JPG Type: image/jpeg Size: 61085 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20080804/689bbb91/attachment-0001.jpeg From phk at phk.freebsd.dk Mon Aug 4 06:36:30 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Mon, 04 Aug 2008 10:36:30 +0000 Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser In-Reply-To: Your message of "Mon, 04 Aug 2008 19:47:16 +1000." Message-ID: <1636.1217846190@critter.freebsd.dk> In message , "Jim Palfreyman" writes: >I find the residuals fascinating. Note the identical repeating residuals in >a 24 hour cycle. > >Is this due to thermal or constellation issues? That is almost 100% guaranteed to be constellation issues. Notice that 5m antenna offset is 15 nanolightseconds. -- 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 Mon Aug 4 10:34:48 2008 From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson) Date: Mon, 04 Aug 2008 16:34:48 +0200 Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser In-Reply-To: <1636.1217846190@critter.freebsd.dk> References: <1636.1217846190@critter.freebsd.dk> Message-ID: <1217860488.7397.49.camel@bg-desktop> On Mon, 2008-08-04 at 10:36 +0000, Poul-Henning Kamp wrote: > In message , "Jim > Palfreyman" writes: > > >I find the residuals fascinating. Note the identical repeating residuals in > >a 24 hour cycle. > > > >Is this due to thermal or constellation issues? > > That is almost 100% guaranteed to be constellation issues. My vote is on antenna multipath. -- Bj?rn From tom.k3io at gmail.com Tue Aug 5 01:08:10 2008 From: tom.k3io at gmail.com (Tom Clark, K3IO) Date: Tue, 05 Aug 2008 01:08:10 -0400 Subject: [time-nuts] time-nuts Digest, Vol 49, Issue 4 In-Reply-To: References: Message-ID: <4897E03A.5090508@verizon.net> Jim Palfreyman noted I took my recently acquired Thunderbolt, along with my 5370B, to the observatory on the weekend and plotted its residual against the NR Active Hydrogen Maser. See the attached graph (ignore the "line of best fit" heading - 0.00 was simply the starting point). Note that I didn't let the Thunderbolt do a survey, I simply plugged in the local GPS coordinates which I later verified were about 5m to the east of the actual Thunderbolt antenna. The y axis is residual in nanoseconds and the x axis is Modified Julian Date. I find the residuals fascinating. Note the identical repeating residuals in a 24 hour cycle. Is this due to thermal or constellation issues? The local GPS (not a GPSDO but an early version Totally Accurate Clock) showed a roughly (very roughly) similar pattern when averaged with 5 minute averages to hide the awful 100nsec sawtooth. Not at all unexpected. I recommend you look at 3 papers on our archive at [1]http://gpstime.com/: In "Low-cost, High Accuracy GPS Timing" you will see the state-of-the-art circa 2000. In slide 16 you see the same type of diurnal bumps, which are due to the residual ionosphere. The GPS satellite broadcast message contains a gross ionospheric correction number based on sunspot count and 2.7 GHz solar flux. But the typical single-frequency receiver has ZERO correction for a day-night ionospheric cycle. At the GPS frequency (1575.42 MHz) the total effect of the ionosphere in the zenith is about 5 meters; the effect at lower elevation angles is even more -- say 7 meters or so. And the day-night variation (max late afternoon local time so GPS runs slow, min early morning so GPS is fast) typically is in the range of 5 meters = 15 nsec or so. In "Critical Evaluation of the Motorola M12+ ..." take a look at Figure 7 (in the PDF) or slides 17/18 (in PPT). You will see the diurnal ionosphere causing ~10-20 nsec of variability and even a 50 nsec excursion due to a large solar "incident". The 2007 version of my "Timing for VLBI " tutorial shows some more modern data, including a description of what causes the "awful sawtooth" and how it can be removed in hardware. FYI -- the 100 nsec sawtooth you see was characteristic of the early 6- and 8-channel Motorola Oncore receivers that I used in my original TACs and Rick used in the first generation of CNS Clocks. When Motorola brought out their new M12-series, the magnitude dropped to ~24 nsec. And it could always be removed in software (even with the older receivers); a binary message from the receiver tells the user the size of the error (quantized in 1 nsec steps) of the next 1PPS tick. Rick's TAC32 software can log the corrected 1PPS value from a low-cost (HP53131/132) counter, so the "ugly sawtooth" is never a problem. Of course. averaging over tens of minutes wipes out the effect too -- just look at the 1995 results from Onsala in the papers. Regards, Tom References 1. http://gpstime.com/ From rk at timing-consultants.com Tue Aug 5 03:26:16 2008 From: rk at timing-consultants.com (Rob Kimberley) Date: Tue, 5 Aug 2008 08:26:16 +0100 Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser In-Reply-To: References: Message-ID: <0DF05B40E876451F82670FEE4D99EC8A@Robin> I'm pretty certain that this due to position error. You state that you have a 5m error in position. 5m equates to approximately 15nS. Having seen similar results before from positional errors it would be good idea to let the unit self survey and then run the tests again. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Jim Palfreyman Sent: 04 August 2008 10:47 To: time-nuts at febo.com Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser Hi folks, I took my recently acquired Thunderbolt, along with my 5370B, to the observatory on the weekend and plotted its residual against the NR Active Hydrogen Maser. See the attached graph (ignore the "line of best fit" heading - 0.00 was simply the starting point). Note that I didn't let the Thunderbolt do a survey, I simply plugged in the local GPS coordinates which I later verified were about 5m to the east of the actual Thunderbolt antenna. The y axis is residual in nanoseconds and the x axis is Modified Julian Date. I find the residuals fascinating. Note the identical repeating residuals in a 24 hour cycle. Is this due to thermal or constellation issues? The local GPS (not a GPSDO but an early version Totally Accurate Clock) showed a roughly (very roughly) similar pattern when averaged with 5 minute averages to hide the awful 100nsec sawtooth. The observatory is air conditioned (but with poor insulation) and has many devices constantly running. I doubt it is thermal, however the low point is at 6:30am in the morning, just before I arrived. Can anyone provide comment on this pattern? Regards, Jim From jim77742 at gmail.com Tue Aug 5 05:55:27 2008 From: jim77742 at gmail.com (jim77742 at gmail.com) Date: Tue, 5 Aug 2008 19:55:27 +1000 Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser In-Reply-To: <0DF05B40E876451F82670FEE4D99EC8A@Robin> References: <0DF05B40E876451F82670FEE4D99EC8A@Robin> Message-ID: So why did the Totally Accurate Clock show the same pattern? On 05/08/2008, Rob Kimberley wrote: > I'm pretty certain that this due to position error. You state that you have > a 5m error in position. 5m equates to approximately 15nS. > > Having seen similar results before from positional errors it would be good > idea to let the unit self survey and then run the tests again. > > Rob Kimberley > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On > Behalf Of Jim Palfreyman > Sent: 04 August 2008 10:47 > To: time-nuts at febo.com > Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser > > Hi folks, > > I took my recently acquired Thunderbolt, along with my 5370B, to the > observatory on the weekend and plotted its residual against the NR Active > Hydrogen Maser. See the attached graph (ignore the "line of best fit" > heading - 0.00 was simply the starting point). > > Note that I didn't let the Thunderbolt do a survey, I simply plugged in the > local GPS coordinates which I later verified were about 5m to the east of > the actual Thunderbolt antenna. > > The y axis is residual in nanoseconds and the x axis is Modified Julian > Date. > > I find the residuals fascinating. Note the identical repeating residuals in > a 24 hour cycle. > > Is this due to thermal or constellation issues? > > The local GPS (not a GPSDO but an early version Totally Accurate Clock) > showed a roughly (very roughly) similar pattern when averaged with 5 minute > averages to hide the awful 100nsec sawtooth. > > The observatory is air conditioned (but with poor insulation) and has many > devices constantly running. I doubt it is thermal, however the low point is > at 6:30am in the morning, just before I arrived. > > Can anyone provide comment on this pattern? > > Regards, > > Jim > > > _______________________________________________ > time-nuts mailing list -- 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 Tue Aug 5 06:11:45 2008 From: rk at timing-consultants.com (Rob Kimberley) Date: Tue, 5 Aug 2008 11:11:45 +0100 Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser In-Reply-To: References: <0DF05B40E876451F82670FEE4D99EC8A@Robin> Message-ID: <0951A102E38A4868A146F4C42C30BE0C@Robin> Good point. How was the position of the so called "Totally Accurate Clock" obtained. Strange name though - no such thing as a totally accurate clock... :-) Rob -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of jim77742 at gmail.com Sent: 05 August 2008 10:55 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt v Active Hydrogen Maser So why did the Totally Accurate Clock show the same pattern? On 05/08/2008, Rob Kimberley wrote: > I'm pretty certain that this due to position error. You state that you > have a 5m error in position. 5m equates to approximately 15nS. > > Having seen similar results before from positional errors it would be > good idea to let the unit self survey and then run the tests again. > > Rob Kimberley > > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] > On Behalf Of Jim Palfreyman > Sent: 04 August 2008 10:47 > To: time-nuts at febo.com > Subject: [time-nuts] Thunderbolt v Active Hydrogen Maser > > Hi folks, > > I took my recently acquired Thunderbolt, along with my 5370B, to the > observatory on the weekend and plotted its residual against the NR > Active Hydrogen Maser. See the attached graph (ignore the "line of best fit" > heading - 0.00 was simply the starting point). > > Note that I didn't let the Thunderbolt do a survey, I simply plugged > in the local GPS coordinates which I later verified were about 5m to > the east of the actual Thunderbolt antenna. > > The y axis is residual in nanoseconds and the x axis is Modified > Julian Date. > > I find the residuals fascinating. Note the identical repeating > residuals in a 24 hour cycle. > > Is this due to thermal or constellation issues? > > The local GPS (not a GPSDO but an early version Totally Accurate > Clock) showed a roughly (very roughly) similar pattern when averaged > with 5 minute averages to hide the awful 100nsec sawtooth. > > The observatory is air conditioned (but with poor insulation) and has > many devices constantly running. I doubt it is thermal, however the > low point is at 6:30am in the morning, just before I arrived. > > Can anyone provide comment on this pattern? > > Regards, > > Jim > > > _______________________________________________ > time-nuts mailing list -- 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 mensa999 at aol.com Tue Aug 5 11:30:55 2008 From: mensa999 at aol.com (MENSA999) Date: Tue, 5 Aug 2008 11:30:55 -0400 Subject: [time-nuts] TrueTime XL-DC Problems Message-ID: This is a long shot but I am hoping that someone might be able to give me some Hints as to a problem that I am having with a Used 151-601 XL-DC Receiver that I recently purchased. When I first fired it up it showed a date of 1990 so I updated the Date to the current one and then went through a 24 hour Auto Mode set up. Once the receiver went into Time mode at the end of set up. I pushed the Location button and noted A good Lat, Lon and elevation had been established. The LCD was showing 3D for the most part and 5 or 6 SAT PRN's. Looking at Osc Stats I see Offsets ranging from the 10 -10 to 10 -12, Drift 10-08 to 10-09, Phase 10-08 to 10-10 and DAC ranging very slowly from 15950 up to 16400 or so. Now the bad news after days of operation I am still showing GPS Unlocked, Position, Time Unknown (Even though a Lat, Lon had been established and UTC had been added through a Function command), Time Error and Acquisition Error ; when I do a F73 "Show Faults" . I seem to be acquiring the satellites but not decoding their full message. I am not sure if this is due to a mistake I am making or a receiver failure. Any suggestions that anyone can give would be ever so greatly appreciated for I am at a loss and so far my web searches have been fruitless. Thank you all for your consideration in this..... Herb Belin Mensa999 at aol.com or 413 530 0048 From mensa999 at aol.com Tue Aug 5 11:51:20 2008 From: mensa999 at aol.com (MENSA999) Date: Tue, 5 Aug 2008 11:51:20 -0400 Subject: [time-nuts] Truetime XL-DC Problems "2nd try" Message-ID: <439d0694.7a9c.4958.9667.09bf9906ad9d@aol.com> This is a long shot but I am hoping that someone might be able to give me some Hints as to a problem that I am having with a Used 151-601 XL-DC Receiver that I recently purchased. When I first fired it up it showed a date of 1990 so I updated the Date to the current one and then went through a 24 hour Auto Mode set up. Once the receiver went into Time mode at the end of set up. I pushed the Location button and noted A good Lat, Lon and elevation had been established. The LCD was showing 3D for the most part and 5 or 6 SAT PRN's. Looking at Osc Stats I see Offsets ranging from the 10 -10 to 10 -12, Drift 10-08 to 10-09, Phase 10-08 to 10-10 and DAC ranging very slowly from 15950 up to 16400 or so. Now the bad news after days of operation I am still showing GPS Unlocked, Position, Time Unknown (Even though a Lat, Lon had been established and UTC had been added through a Function command), Time Error and Acquisition Error ; when I do a F73 "Show Faults" . I seem to be acquiring the satellites but not decoding their full message. I am not sure if this is due to a mistake I am making or a receiver failure. Any suggestions that anyone can give would be ever so greatly appreciated for I am at a loss and so far my web searches have been fruitless. Thank you all for your consideration in this..... Herb Belin Mensa999 at aol.com or 413 530 0048 From w4oa at vibroplex.com Tue Aug 5 12:23:46 2008 From: w4oa at vibroplex.com (F Mitchell) Date: Tue, 5 Aug 2008 11:23:46 -0500 Subject: [time-nuts] Power supply for Thunderbolt Message-ID: Anyone have a suggestion for a power supply for the Thunderbolt? Thanks Mitch W4OA From w1ksz at earthlink.net Tue Aug 5 12:29:13 2008 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Tue, 5 Aug 2008 09:29:13 -0700 (GMT-07:00) Subject: [time-nuts] HP 5354A Plug-In Wanted Message-ID: <32332144.1217953754170.JavaMail.root@elwamui-cypress.atl.sa.earthlink.net> I acquired the counter (5345A) from a list member and would loke to get a Plug-In for it. I got sniped on one "over there". Anyone have a working 5354A they will part with ?? Thanks, Dick, W1KSZ From mensa999 at aol.com Tue Aug 5 12:56:37 2008 From: mensa999 at aol.com (MENSA999) Date: Tue, 5 Aug 2008 12:56:37 -0400 Subject: [time-nuts] (no subject) Message-ID: <2bc78ee1.5275.446e.bd29.e6b741ade1de@aol.com> This is a long shot but I am hoping that someone might be able to give me some Hints as to a problem that I am having with a Used 151-601 XL-DC Receiver that I recently purchased. When I first fired it up it showed a date of 1990 so I updated the Date to the current one using an "F" function and then went through a 24 hour Auto Mode set up. Once the receiver went into Time mode at the end of set up. I pushed the Location button and noted A good Lat, Lon and elevation had been established. The LCD was showing 3D for the most part and 5 or 6 SAT PRN's. Looking at Osc Stats I see Offsets ranging from the 10 -10 to 10 -12, Drift 10-08 to 10-09, Phase 10-08 to 10-10 and DAC ranging very slowly from 15950 up to 16400 or so. Now the bad news after days of operation when I run an F73 "Show Faults I am still showing GPS Unlocked, Position, Time Unknown (Even though a Lat, Lon had been established and UTC had been added through a Function command), and lastly a Time Error and Acquisition Error. I seem to be acquiring the satellites but not decoding their full message. I am not sure if this is due to a mistake I am making or a receiver failure. Any suggestions that anyone can give would be ever so greatly appreciated for I am at a loss and so far my web searches have been fruitless. Thank you all for your consideration in this..... Herb Belin Mensa999 at aol.com or 413 530 0048 Sorry for the repeats on this but I guess I have to ad carrige returns manually... From david.partridge at dsl.pipex.com Tue Aug 5 13:02:17 2008 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Tue, 5 Aug 2008 18:02:17 +0100 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: References: Message-ID: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> I'm using the Meanwell T30-B, but Tom van Baak's test on this shows a bit of phase noise at 1Hz offset which is a tad nasty: http://www.leapsecond.com/pages/tbolt/noise.htm I'm wondering if this can be reduced with a bit of extra de-coupling on the 5V supply, but haven't got round to scoping the 5V supply to see what happens every second (presumably as the output is sent to the serial port). Cheers Dave -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of F Mitchell Sent: 05 August 2008 17:24 To: time-nuts at febo.com Subject: [time-nuts] Power supply for Thunderbolt Anyone have a suggestion for a power supply for the Thunderbolt? Thanks Mitch W4OA _______________________________________________ time-nuts mailing list -- 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 gwinn at raytheon.com Tue Aug 5 10:53:24 2008 From: gwinn at raytheon.com (Joseph M Gwinn) Date: Tue, 5 Aug 2008 10:53:24 -0400 Subject: [time-nuts] LPRO 101 ADJUSTMENT In-Reply-To: Message-ID: time-nuts-bounces at febo.com wrote on 08/02/2008 04:38:14 PM: > [snip] > > It would be nice to find a relatively simple and inexpensive 10MHz > synthesizer that has a resolution of closer to 1E-14 to avoid messing > with the EFC at all. A 48-bit-accumulator DDS chip such as the Analog Devices AD9852 will achieve such frequency resolution: 2^-48= 3.6*10^-15, call it 10^-14. The issue with a DDS is handling the various spurs. Arbitrary function generators such as the Agilent 34220A-001 (the -001 option means that an external 10 MHz reference signal is accepted) will also do the job, in a nice albeit expensive ($2.4K new) package. Joe Gwinn From bg at lysator.liu.se Tue Aug 5 13:33:24 2008 From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson) Date: Tue, 05 Aug 2008 19:33:24 +0200 Subject: [time-nuts] TrueTime XL-DC Problems In-Reply-To: References: Message-ID: <1217957604.7397.83.camel@bg-desktop> Hi Herb, I am not familiar with the details of the XL-DC. So if you get more informed suggestions, try them first... However your GPS receiver may be bitten by the GPS week rollower problem. http://www.colorado.edu/geography/gcraft/notes/gps/gpseow.htm http://tycho.usno.navy.mil/gps_week.html It is now GPS WK 1491 (467+1024). The GPS receiver firmware could have been "week-rollover-safe" by adding 1023 to "small" week numbers. Try to identify the GPS receiver model and search information on that particular unit. Can you eavesdrop on the GPS module? (Easier if it uses an ASCII NMEA message, more work if its a binary protocol). Check that it does output a valid date. Your model seems to be current with the manufacturer. Have you checked for the latest firmware? The DAC seem to move in the middle of the range. But have you double checked that the 10MHz output is as good as the unit says? Good Luck! -- Bj?rn On Tue, 2008-08-05 at 11:30 -0400, MENSA999 wrote: > This is a long shot but I am hoping that someone might be able to give > me some Hints as to a problem that I am having with a Used 151-601 > XL-DC Receiver that I recently purchased. When I first fired it up it > showed a date of 1990 so I updated the Date to the current one and > then went through a 24 hour Auto Mode set up. Once the receiver went > into Time mode at the end of set up. I pushed the Location button and > noted A good Lat, Lon and elevation had been established. The LCD was > showing 3D for the most part and 5 or 6 SAT PRN's. Looking at Osc > Stats I see Offsets ranging from the 10 -10 to 10 -12, Drift 10-08 to > 10-09, Phase 10-08 to 10-10 and DAC ranging very slowly from 15950 up > to 16400 or so. Now the bad news after days of operation I am still > showing GPS Unlocked, Position, Time Unknown (Even though a Lat, Lon > had been established and UTC had been added through a Function > command), Time Error and Acquisition Error ; when I do a F73 "Show > Faults" . I seem to be acquiring the satellites but not decoding their > full message. I am not sure if this is due to a mistake I am making or > a receiver failure. > Any suggestions that anyone can give would be ever so greatly > appreciated for I am at a loss and so far my web searches have been > fruitless. Thank you all for your consideration in this..... > > Herb Belin > > Mensa999 at aol.com or 413 530 0048 > _______________________________________________ > time-nuts mailing list -- 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 support at prologix.biz Tue Aug 5 13:38:35 2008 From: support at prologix.biz (Prologix) Date: Tue, 5 Aug 2008 10:38:35 -0700 Subject: [time-nuts] New Prologix GPIB-LAN Controller Message-ID: Hello, Prologix is happy to announce its newest product - GPIB-LAN Controller. Access your GPIB enabled instruments over a network (even over wireless) using the affordable, easy to use, Prologix GPIB-LAN controller! Use this controller to control, and to download screen plots and data from, Oscilloscopes, Logic Analyzers, Spectrum Analyzers and other GPIB enabled instruments. GPIB-LAN controller uses the same command interface as the popular Prologix GPIB-USB controller; the only difference is you connect to a TCP port instead of over USB. Being a network device there are no drivers to install. * No drivers required * Support for multiple devices * No GPIB cable needed; controller plugs on to instrument * All software configuration. No switches * Standard RJ-45 and IEEE 488 (Male) connectors Thanks to John Miles for adapting KE5FX GPIB toolkit to support Prologix GPIB-LAN controller. Now you can use the popular 7470, SSM and PN utilities over the net. Thanks to Ulrich Bangert for adapting EZGPIB to support Prologix GPIB-LAN controller http://store.prologix.biz/gpiblan-controller.html Regards, Abdul support at prologix.biz From boyscout at gmail.com Tue Aug 5 13:47:17 2008 From: boyscout at gmail.com (Matt Ettus) Date: Tue, 5 Aug 2008 10:47:17 -0700 Subject: [time-nuts] New Prologix GPIB-LAN Controller In-Reply-To: References: Message-ID: On Tue, Aug 5, 2008 at 10:38 AM, Prologix wrote: > Hello, > > > > Prologix is happy to announce its newest product - GPIB-LAN Controller. Will there be VXI-11 support? The ICS 8065 and Agilent E5810A both support it, along with most of the new test equipment that talks ethernet. It would be nice not to have to rewrite apps. Matt From GDowd at symmetricom.com Tue Aug 5 14:31:00 2008 From: GDowd at symmetricom.com (Greg Dowd) Date: Tue, 5 Aug 2008 11:31:00 -0700 Subject: [time-nuts] TrueTime XL-DC Problems In-Reply-To: References: Message-ID: Have you tried Symmetricom tech support? Truetime is now part of Symm's Timing, Test and Measurement division. Greg Dowd gdowd at symmetricom dot com (antispam format) Symmetricom, Inc. www.symmetricom.com "Everything should be made as simple as possible, but no simpler" Albert Einstein -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of MENSA999 Sent: Tuesday, August 05, 2008 8:31 AM To: time-nuts at febo.com Subject: [time-nuts] TrueTime XL-DC Problems This is a long shot but I am hoping that someone might be able to give me some Hints as to a problem that I am having with a Used 151-601 XL-DC Receiver that I recently purchased. When I first fired it up it showed a date of 1990 so I updated the Date to the current one and then went through a 24 hour Auto Mode set up. Once the receiver went into Time mode at the end of set up. I pushed the Location button and noted A good Lat, Lon and elevation had been established. The LCD was showing 3D for the most part and 5 or 6 SAT PRN's. Looking at Osc Stats I see Offsets ranging from the 10 -10 to 10 -12, Drift 10-08 to 10-09, Phase 10-08 to 10-10 and DAC ranging very slowly from 15950 up to 16400 or so. Now the bad news after days of operation I am still showing GPS Unlocked, Position, Time Unknown (Even though a Lat, Lon had been established and UTC had been added through a Function command), Time Error and Acquisition Error ; when I do a F73 "Show Faults" . I seem to be acquirin g the satellites but not decoding their full message. I am not sure if this is due to a mistake I am making or a receiver failure. Any suggestions that anyone can give would be ever so greatly appreciated for I am at a loss and so far my web searches have been fruitless. Thank you all for your consideration in this..... Herb Belin Mensa999 at aol.com or 413 530 0048 _______________________________________________ time-nuts mailing list -- 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 N3IZN at aol.com Tue Aug 5 16:07:55 2008 From: N3IZN at aol.com (N3IZN at aol.com) Date: Tue, 5 Aug 2008 16:07:55 EDT Subject: [time-nuts] Trimble GPSDO unit for sale - SOLD Message-ID: Sorry for not getting back to every one who inquired about the GPS unit I had for sale. I answered the emails in the order I got them and after a couple of no goes, I finally found a new home for it. There were a lot of emails and thought a group reply would be easier. Sorry for the bandwidth. Chris **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 ) From tom.k3io at gmail.com Tue Aug 5 17:10:15 2008 From: tom.k3io at gmail.com (Tom Clark, K3IO) Date: Tue, 05 Aug 2008 17:10:15 -0400 Subject: [time-nuts] The name "Totally Accurate Clock" Message-ID: <4898C1B7.4050004@verizon.net> Rob noted: Good point. How was the position of the so called "Totally Accurate Clock" obtained. Strange name though - no such thing as a totally accurate clock... :-) Rob Here is the story -- and some of the details are in my contributions on [1]http://gpstime.com: For many, many moons, I headed up NASA's program that developed Very Long Baseline Interferometry (VLBI) as a tool to make various geophysical measurements. The measurements yielded up * Accurate vector determination of the motions of the earth's tectonic plates ("continental drift", now known to ~20 microns/yr). * Very accurate measures of the rotation of the earth with respect to the celestial reference frame, aka UT1 (in effect "sundial time"), now observed at levels of a few tens of usec on a daily basis. VLBI is the "official" BIPM and USNO source of UT1, including the info on which we have a leap-second pending. * Accurate positions of the earth's rotation pole (polar motion, nutation & precession) and of a few hundred extragalactic radio sources at the sub-milliarcsecond level. * And some nifty astronomy too! Each VLBI station around the world has a Hydrogen Maser as its local clock (Jim Palfreyman's note concerned the VLBI station near Hobart, Tasmania) serving as both the stable short-term phase reference for microwave observations, as the timing clocks for data bits written onto tape (now replaced with disk arrays), and as the still longer term reference to tie between UT1 and UTC. If you look at my VLBI timing tutorials on [2]http://gpstime.com you will see info on VLBI's timing requirements. In the good old days (thru the mid-80s) we used some combination of Loran and traveling clocks to keep the network tied together. In the mid-80s we started using GPS for the task. The original GPS receivers were large, clunky devices. In the mid-90s I decided to come up with low-cost GPS timing receiver for the VLBI stations and I needed a short catchy name. At that time, Heathkit was selling a WWV receiver which could produce timing at levels of a few msec (on a good day) & Heath called it "The Most Accurate Clock". Also around that time, Hammacher-Schlemer was selling a WWVB wall clock that they also called "The Most Accurate Clock". My simple timing receiver was already producing sub-usec results using Motorola's PVT-6 "Six-Pack" 6-channel receiver, even in the face of Selective Availability (SA). Since I was achieving several orders-of-magnitude better results than the commercial "Most" receivers and since we could trace its ACCURACY all the way back to the USNO master clock, I needed a word much stronger than "Most" and thus was born the "Totally Accurate Clock" name; I modestly note the coincidence that TAC happen to be my initials! I began a campaign of replacing the timing systems at various stations with the first batch of 25 TACs using the PVT-6 receivers; I think that the unit Jim used for his GPSDO was an original 6-channel unit. You can judge the performance back then by the 6-week span of Maser/TAC data from Onsala Sweden plotted in my tutorials. Joe Taylor (Nobel Prize for his Pulsar work) verified that the original TAC was able to transfer time to Arecibo at levels of accuracy comparable to NIST's common view time transfer system (the service and equipment rental cost ~$5k/yr). Motorola then came out with their ONCORE series with 6 and then 8 channel receivers and I updated the design to the TAC-2. Because there was a lot of interest outside the VLBI community, I worked with TAPR to make a kit-form TAC-2 available to anyone. My friend Rick Hambly ([3]http://www.cnssys.com) saw a need for this receiver in a turn-key form, so he put the TAC-2 into his CNS Clock. He also transformed my crude "SHOWTIME" TAC support software into a full Windoze-based application which he called TAC32. He rolled into TAC32 the ability to automatically correct the timing results for the annoying 100 nsec sawtooth dither by providing a way to read a low-cost HP 53131 (or 132) counter, correcting its reading, and generating corrected logs. All told, between TAPR and CNS, something like 1000 of my TAC-2s found their way into the world. Rick has also adapted the newer Motorola (now iLotus) M12+ 12 channel receivers and has now rolled out is CNS Clock 2 which includes hardware sawtooth removal, IRIG time codes, a GPSDO and a bunch of other widgets. See his web site for more details. In the meantime, I retired from NASA in 2001 but I still stay involved with the VLBI and timing communities as the resident curmudgeon and referee of mis-spoken factoids. So that's where the name came from and how it evolved. Tom Clark References 1. http://gpstime.com/ 2. http://gpstime.com/ 3. http://www.cnssys.com/ From magnus at rubidium.dyndns.org Tue Aug 5 17:51:51 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Tue, 05 Aug 2008 23:51:51 +0200 Subject: [time-nuts] The name "Totally Accurate Clock" In-Reply-To: <4898C1B7.4050004@verizon.net> References: <4898C1B7.4050004@verizon.net> Message-ID: <4898CB77.9020608@rubidium.dyndns.org> Tom, Thanks for a fashinating little story! Cheers, Magnus From bruce.griffiths at xtra.co.nz Tue Aug 5 18:43:03 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 06 Aug 2008 10:43:03 +1200 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> Message-ID: <4898D777.1030909@xtra.co.nz> David C. Partridge wrote: > I'm using the Meanwell T30-B, but Tom van Baak's test on this shows a bit of > phase noise at 1Hz offset which is a tad nasty: > > http://www.leapsecond.com/pages/tbolt/noise.htm > > I'm wondering if this can be reduced with a bit of extra de-coupling on the > 5V supply, but haven't got round to scoping the 5V supply to see what > happens every second (presumably as the output is sent to the serial port). > > Cheers > Dave > > Dave If phase noise at 1Hz offset is a problem you will probably need a power supply filter with cutoff frequency well below 1Hz to make any discernable difference. Since the an RC filter will produce a voltage drop in the 5V supply the resistor value will have to be kept small and the capacitor value correspondingly large (several farads). It may be possible to stack 3 low ESR super capacitors in series (maximum voltage rating is around 2v -2.5V those with higher ratings are actually series connected stacks) to do this but this is a relatively expensive proposition. Alternatively a modified version of the Wenzel active power supply filter could be used if a series stack of 2 low ESR supercaps were substituted for the capacitor connected from the supply to the transistor base. The modified circuit stabilises the transistor's effective emitter resistance and keeps the active filter dc current low. It may also be possible to use a variation of Wenzel's opamp augmented active filter scheme, however the filter low frequency cutoff will have to be well below 1Hz for it to be effective. Bruce From James.P.Lux at jpl.nasa.gov Tue Aug 5 19:12:35 2008 From: James.P.Lux at jpl.nasa.gov (Jim Lux) Date: Tue, 05 Aug 2008 16:12:35 -0700 Subject: [time-nuts] The name "Totally Accurate Clock" In-Reply-To: <4898C1B7.4050004@verizon.net> References: <4898C1B7.4050004@verizon.net> Message-ID: <6.2.5.6.2.20080805155819.02da7f60@jpl.nasa.gov> At 02:10 PM 8/5/2008, Tom Clark, K3IO wrote: > Rob noted: > >Good point. How was the position of the so called "Totally Accurate Clock" >obtained. Strange name though - no such thing as a totally accurate clock... > > :-) > >Rob > > Here is the story -- and some of the details are in my contributions on > [1]http://gpstime.com: > For many, many moons, I headed up NASA's program that developed Very > Long Baseline Interferometry (VLBI) as a tool to make various > geophysical measurements. The measurements yielded up > * Accurate vector determination of the motions of the earth's > tectonic plates ("continental drift", now known to ~20 microns/yr). > * Very accurate measures of the rotation of the earth with respect to > the celestial reference frame, aka UT1 (in effect "sundial time"), > now observed at levels of a few tens of usec on a daily basis. VLBI > is the "official" BIPM and USNO source of UT1, including the info > on which we have a leap-second pending. > * Accurate positions of the earth's rotation pole (polar motion, > nutation & precession) and of a few hundred extragalactic radio > sources at the sub-milliarcsecond level. > * And some nifty astronomy too! And, such things as one way DeltaDOR measurements for navigation of deep space probes, and straight interferometry for measuring the position of the Lunar Rover. (the paper after yours at the 1972 PTTI conference) Other nifty applications at: http://www.sciencemag.org/cgi/reprint/sci;178/4061/607.pdf by Counselman, et al. Also used to do stuff like measure the winds on Titan and Venus. (but that's the astronomy Tom referred to) > Each VLBI station around the world has a Hydrogen Maser as its local > clock (Jim Palfreyman's note concerned the VLBI station near Hobart, > Tasmania) serving as both the stable short-term phase reference for > microwave observations, as the timing clocks for data bits written onto > tape (now replaced with disk arrays), and as the still longer term > reference to tie between UT1 and UTC. If you look at my VLBI timing > tutorials on [2]http://gpstime.com you will see info on VLBI's timing > requirements. For DeltaDOR they use a quasar as the (almost)simultaneous reference. I would have thought there would be a easy to find JPL reference on this (since we actually do it here, on the recent Phoenix landing, for instance), but it would appear that ESA has the nice description. http://www.esa.int/esapub/bulletin/bulletin128/bul128i_madde.pdf Here's a very simple description http://www2.jpl.nasa.gov/basics/bsf13-1.html Jim From GandalfG8 at aol.com Tue Aug 5 19:21:04 2008 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Tue, 5 Aug 2008 19:21:04 EDT Subject: [time-nuts] The name "Totally Accurate Clock" Message-ID: In a message dated 06/08/2008 00:15:08 GMT Daylight Time, James.P.Lux at jpl.nasa.gov writes: Also used to do stuff like measure the winds on Titan and Venus ------------------------ I did that once, but it's a pig of a job and was glad to get back!! From James.P.Lux at jpl.nasa.gov Tue Aug 5 19:37:07 2008 From: James.P.Lux at jpl.nasa.gov (Jim Lux) Date: Tue, 05 Aug 2008 16:37:07 -0700 Subject: [time-nuts] The name "Totally Accurate Clock" In-Reply-To: References: Message-ID: <6.2.5.6.2.20080805163616.02dfa130@jpl.nasa.gov> At 04:21 PM 8/5/2008, you wrote: >In a message dated 06/08/2008 00:15:08 GMT Daylight Time, >James.P.Lux at jpl.nasa.gov writes: > > >Also used to do stuff like measure the winds on Titan and Venus >------------------------ > > >I did that once, but it's a pig of a job and was glad to get back!! Yeah.. either your wet finger freezes or the acid burns are painful. From quenbob5 at pacbell.net Tue Aug 5 19:58:20 2008 From: quenbob5 at pacbell.net (Bob Q) Date: Tue, 5 Aug 2008 16:58:20 -0700 Subject: [time-nuts] Power supply for Thunderbolt References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> <4898D777.1030909@xtra.co.nz> Message-ID: <000a01c8f757$2402ae30$1801a8c0@BOBCEL1R7> I had a similar problem with my home-brew design. I found a "blip" with 1 second period on the output of the error amplifier. I couldn't eliminate it with extra power supply filtering. The high gain of the error amplifier picked up a very small voltage that developed on "ground". I solved it by supplying the phase detector and error amplifier with a separate 5 V supply. I tied the ground pin of the new 5 V regulator very close to the phase detector ground pin. Bob Q. ----- Original Message ----- From: "Bruce Griffiths" To: "Discussion of precise time and frequency measurement" Sent: Tuesday, August 05, 2008 3:43 PM Subject: Re: [time-nuts] Power supply for Thunderbolt > David C. Partridge wrote: >> I'm using the Meanwell T30-B, but Tom van Baak's test on this shows a bit >> of >> phase noise at 1Hz offset which is a tad nasty: >> >> http://www.leapsecond.com/pages/tbolt/noise.htm >> >> I'm wondering if this can be reduced with a bit of extra de-coupling on >> the >> 5V supply, but haven't got round to scoping the 5V supply to see what >> happens every second (presumably as the output is sent to the serial >> port). >> >> Cheers >> Dave >> >> > Dave > > If phase noise at 1Hz offset is a problem you will probably need a > power supply filter with cutoff frequency well below 1Hz to make any > discernable difference. > Since the an RC filter will produce a voltage drop in the 5V supply the > resistor value will have to be kept small and the capacitor value > correspondingly large (several farads). > It may be possible to stack 3 low ESR super capacitors in series > (maximum voltage rating is around 2v -2.5V those with higher ratings are > actually series connected stacks) to do this but this is a relatively > expensive proposition. > > Alternatively a modified version of the Wenzel active power supply > filter could be used if a series stack of 2 low ESR supercaps were > substituted for the capacitor connected from the supply to the > transistor base. The modified circuit stabilises the transistor's > effective emitter resistance and keeps the active filter dc current low. > > It may also be possible to use a variation of Wenzel's opamp augmented > active filter scheme, however the filter low frequency cutoff will have > to be well below 1Hz for it to be effective. > > 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 Tue Aug 5 20:46:44 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 06 Aug 2008 12:46:44 +1200 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: <000a01c8f757$2402ae30$1801a8c0@BOBCEL1R7> References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> <4898D777.1030909@xtra.co.nz> <000a01c8f757$2402ae30$1801a8c0@BOBCEL1R7> Message-ID: <4898F474.1010402@xtra.co.nz> Bob Q wrote: > I had a similar problem with my home-brew design. I found a "blip" with 1 > second period on the output of the error amplifier. I couldn't eliminate > it with extra power supply filtering. The high gain of the error amplifier > picked up a very small voltage that developed on "ground". I solved it by > supplying the phase detector and error amplifier with a separate 5 V supply. > I tied the ground pin of the new 5 V regulator very close to the phase > detector ground pin. > Bob Q. > > Bob That involves an internal modification to the Thunderbolt which isnt really necessary as the problem is known to vanish when the power supply is quiet enough. For performance with other power supplies see: http://www.leapsecond.com/pages/tbolt/noise.htm The only real question are: Is possible to filter the given power supply sufficiently well. Which power supply rails need to be filtered? Bruce From bruce.griffiths at xtra.co.nz Tue Aug 5 21:14:03 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 06 Aug 2008 13:14:03 +1200 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> Message-ID: <4898FADB.8070308@xtra.co.nz> David C. Partridge wrote: > I'm using the Meanwell T30-B, but Tom van Baak's test on this shows a bit of > phase noise at 1Hz offset which is a tad nasty: > > http://www.leapsecond.com/pages/tbolt/noise.htm > > I'm wondering if this can be reduced with a bit of extra de-coupling on the > 5V supply, but haven't got round to scoping the 5V supply to see what > happens every second (presumably as the output is sent to the serial port). > > Cheers > Dave > > Dave Interaction between the power supply switching noise components and internal frequencies in the thunderbolt could produce the 1Hz spur. It would be useful to know the noise spectrum of the power supply outputs both at high and low frequencies. Careful filtering of the HF components of the power supply noise may be effective in reducing such interactions. Alternatively the supply could have a low level 1Hz oscillation superimposed on its output. It may well be easier and more cost effective to just use a lower noise supply rather than adding the complexity and cost of low and high frequency filtering. Bruce From rogburn at warpspeed1.net Tue Aug 5 21:22:22 2008 From: rogburn at warpspeed1.net (Robert Ogburn) Date: Tue, 5 Aug 2008 20:22:22 -0500 Subject: [time-nuts] Trimble Placer GPS400 In-Reply-To: Message-ID: On Monday, 8/4/08 Rob Wrote: -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of Rob Kimberley Sent: Monday, August 04, 2008 3:03 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Trimble Placer GPS400 Bob, SVEESIX is a Trimble GPS engine. From the report, it is telling you that the model you have uses that engine with those version numbers. What are you looking to restore? Not sure I understand your problem. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Ogburn Sent: 03 August 2008 14:48 To: time-nuts at febo.com Subject: [time-nuts] Trimble Placer GPS400 We have a Trimble Placer GPS400 that reports version as: SVEESIX ver 4.06 (05/18/94) core ver 1.17 (12/21/93). Is this correct? If not, how do we restore? Thanks bob ========================================== From optomatic at rogers.com Tue Aug 5 21:46:54 2008 From: optomatic at rogers.com (Patrick) Date: Tue, 05 Aug 2008 21:46:54 -0400 Subject: [time-nuts] New Prologix GPIB-LAN Controller In-Reply-To: References: Message-ID: <4899028E.3080802@rogers.com> Hey Abdul Your new controller is on my shopping list, I just need to wait for some checks to arrive. Good work! -Patrick Prologix wrote: > Hello, > > > > Prologix is happy to announce its newest product - GPIB-LAN Controller. > > > > Access your GPIB enabled instruments over a network (even over wireless) > using the affordable, easy to use, Prologix GPIB-LAN controller! > > > > Use this controller to control, and to download screen plots and data from, > Oscilloscopes, Logic Analyzers, Spectrum Analyzers and other GPIB enabled > instruments. > > > > GPIB-LAN controller uses the same command interface as the popular Prologix > GPIB-USB controller; the only difference is you connect to a TCP port > instead of over USB. Being a network device there are no drivers to install. > > > > * No drivers required > > * Support for multiple devices > > * No GPIB cable needed; controller plugs on to instrument > > * All software configuration. No switches > > * Standard RJ-45 and IEEE 488 (Male) connectors > > > > Thanks to John Miles for adapting KE5FX GPIB toolkit to support Prologix > GPIB-LAN controller. Now you can use the popular 7470, SSM and PN utilities > over the net. > > > > Thanks to Ulrich Bangert for adapting EZGPIB to support Prologix GPIB-LAN > controller > > > > http://store.prologix.biz/gpiblan-controller.html > > > > Regards, > > Abdul > > support at prologix.biz > > > > _______________________________________________ > time-nuts mailing list -- 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 Tue Aug 5 21:55:56 2008 From: tvb at LeapSecond.com (Tom Van Baak) Date: Tue, 5 Aug 2008 18:55:56 -0700 Subject: [time-nuts] TrueTime XL-DC Problems References: Message-ID: <001901c8f767$96e94020$0200a8c0@pc52> > When I first fired it up it showed a date of 1990 so I updated > the Date to the current one and then went through a 24 hour ... I would rather be able give you a solid answer; perhaps someone in the group will step forward with their own XL-DC story. It is possible when an unmodified surplus GPSDO powers up with a default date as old as 1990 and sort-of, partially works, that the cause of the problem is that the firmware is missing the upgrade for either WNRO (21-Aug-1999) or Y2K (31-Dec-1999). Anyone on the list have a working XL-DC? /tvb From n5en at wt.net Tue Aug 5 22:38:07 2008 From: n5en at wt.net (Steve Niles) Date: Tue, 05 Aug 2008 21:38:07 -0500 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: References: Message-ID: <48990E8F.9030303@wt.net> I use this one: http://www.mouser.com/Search/ProductDetail.aspx?qs=RCLU9o6%252bptzs793RA%252bLWWg%3d%3d Mouser p/n 826-LPT43 Seems to work OK. Steve N5EN > Message: 1 > Date: Tue, 5 Aug 2008 11:23:46 -0500 > From: "F Mitchell" > Subject: [time-nuts] Power supply for Thunderbolt > To: > > Anyone have a suggestion for a power supply for the > > Thunderbolt? > > > > Thanks > > Mitch W4OA From w1ksz at earthlink.net Wed Aug 6 00:20:57 2008 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Tue, 5 Aug 2008 21:20:57 -0700 (GMT-07:00) Subject: [time-nuts] TrueTime XL-DC Problems Message-ID: <31837396.1217996458253.JavaMail.root@mswamui-andean.atl.sa.earthlink.net> Not sure what the differences are, but I have two of the XL-AK GPS Receivers, both work. 73, Dick, W1KSZ -----Original Message----- >From: Tom Van Baak >Sent: Aug 5, 2008 6:55 PM >To: Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] TrueTime XL-DC Problems > >> When I first fired it up it showed a date of 1990 so I updated >> the Date to the current one and then went through a 24 hour >... > >I would rather be able give you a solid answer; perhaps someone >in the group will step forward with their own XL-DC story. > >It is possible when an unmodified surplus GPSDO powers up with >a default date as old as 1990 and sort-of, partially works, that the >cause of the problem is that the firmware is missing the upgrade >for either WNRO (21-Aug-1999) or Y2K (31-Dec-1999). > >Anyone on the list have a working XL-DC? > >/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 df6jb at ulrich-bangert.de Wed Aug 6 00:46:35 2008 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Wed, 6 Aug 2008 06:46:35 +0200 Subject: [time-nuts] LPRO 101 ADJUSTMENT In-Reply-To: Message-ID: Jim, > A 48-bit-accumulator DDS chip such as the Analog Devices AD9852 will > achieve such frequency resolution: 2^-48= 3.6*10^-15, call > it 10^-14. The issue with a DDS is handling the various spurs. To be even more precise: It achieves this resolution in terms of the CLOCK frequency and not in terms of the OUTPUT frequency which may be consirable less resolution. Best regards Ulrich Bangert > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Joseph M Gwinn > Gesendet: Dienstag, 5. August 2008 16:53 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] LPRO 101 ADJUSTMENT > > > time-nuts-bounces at febo.com wrote on 08/02/2008 04:38:14 PM: > > > > [snip] > > > > It would be nice to find a relatively simple and > inexpensive 10MHz > > synthesizer that has a resolution of closer to 1E-14 to > avoid messing > > with the EFC at all. > > A 48-bit-accumulator DDS chip such as the Analog Devices AD9852 will > achieve such frequency resolution: 2^-48= 3.6*10^-15, call > it 10^-14. The > issue with a DDS is handling the various spurs. > > Arbitrary function generators such as the Agilent 34220A-001 > (the -001 > option means that an external 10 MHz reference signal is > accepted) will > also do the job, in a nice albeit expensive ($2.4K new) package. > > Joe Gwinn > > _______________________________________________ > time-nuts mailing list -- 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 VK3FGJM at commtelns.com Wed Aug 6 01:01:27 2008 From: VK3FGJM at commtelns.com (VK3FGJM) Date: Wed, 6 Aug 2008 15:01:27 +1000 Subject: [time-nuts] Thunderbolt GPSDO coupled to a Rubidium Message-ID: Hi All, Has anybody integrated a Rubibium 10 MHz clock to their thunderbolt in place of the onboard oven? The reason for the question, I have a perfect working home made Rubidium source and distribution amp that I use in the stack. I have considered integrating it to the Thunderbolt, thus providing better long term accuracy. Maybe it's a waist of time! Regards Gerald Molenkamp VK3FGJM From james.p.lux at jpl.nasa.gov Wed Aug 6 01:16:10 2008 From: james.p.lux at jpl.nasa.gov (Jim Lux) Date: Tue, 05 Aug 2008 22:16:10 -0700 Subject: [time-nuts] LPRO 101 ADJUSTMENT In-Reply-To: References: Message-ID: <20080805221610.t33x9e3msw4ggwso@webmail.jpl.nasa.gov> Quoting Ulrich Bangert , on Tue 05 Aug 2008 09:46:35 PM PDT: > Jim, > >> A 48-bit-accumulator DDS chip such as the Analog Devices AD9852 will >> achieve such frequency resolution: 2^-48= 3.6*10^-15, call >> it 10^-14. The issue with a DDS is handling the various spurs. > > To be even more precise: It achieves this resolution in terms of the > CLOCK frequency and not in terms of the OUTPUT frequency which may be > consirable less resolution. > > Best regards > Ulrich Bangert And the 9852 is the older generation of DDSes from AD. The newer 99xx series is generally better (spur reduction built in, faster clocks, longer registers, more bits in the built in DAC) AND, there's all sorts of schemes combining a DDS and a PLL (granted, this rolls in a whole other set of problems) > >> -----Ursprungliche Nachricht----- >> Von: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Joseph M Gwinn >> Gesendet: Dienstag, 5. August 2008 16:53 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] LPRO 101 ADJUSTMENT >> >> >> time-nuts-bounces at febo.com wrote on 08/02/2008 04:38:14 PM: >> >> > >> [snip] >> > >> > It would be nice to find a relatively simple and >> inexpensive 10MHz >> > synthesizer that has a resolution of closer to 1E-14 to >> avoid messing >> > with the EFC at all. >> >> A 48-bit-accumulator DDS chip such as the Analog Devices AD9852 will >> achieve such frequency resolution: 2^-48= 3.6*10^-15, call >> it 10^-14. The >> issue with a DDS is handling the various spurs. >> >> Arbitrary function generators such as the Agilent 34220A-001 >> (the -001 >> option means that an external 10 MHz reference signal is >> accepted) will >> also do the job, in a nice albeit expensive ($2.4K new) package. >> >> Joe Gwinn >> >> _______________________________________________ >> time-nuts mailing list -- 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 support at prologix.biz Wed Aug 6 09:11:44 2008 From: support at prologix.biz (Prologix) Date: Wed, 6 Aug 2008 06:11:44 -0700 Subject: [time-nuts] New Prologix GPIB-LAN Controller In-Reply-To: Message-ID: Prologix GPIB-LAN provides the same command interface as the popular Prologix GPIB-USB controller, making it easy to adapt existing programs. VXI-11 support may be emulated by developing a host side library. None is planned for now. But that could change depending on customer interest. Regards, Abdul www.prologix.biz -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Matt Ettus Sent: Tuesday, August 05, 2008 10:47 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] New Prologix GPIB-LAN Controller On Tue, Aug 5, 2008 at 10:38 AM, Prologix wrote: > Hello, > > > > Prologix is happy to announce its newest product - GPIB-LAN Controller. Will there be VXI-11 support? The ICS 8065 and Agilent E5810A both support it, along with most of the new test equipment that talks ethernet. It would be nice not to have to rewrite apps. Matt _______________________________________________ time-nuts mailing list -- 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 Wed Aug 6 13:36:07 2008 From: ed_palmer at sasktel.net (Ed Palmer) Date: Wed, 06 Aug 2008 11:36:07 -0600 Subject: [time-nuts] NavSync CW12 and CW25 In-Reply-To: References: Message-ID: <4899E107.7060401@sasktel.net> Has anyone worked with the NavSync CW12 GPS board or the CW25 module that its based on? It's been mentioned a few times on this mailing list, but not really evaluated or discussed to death. :-) I'm looking for a new GPS board and this one looks quite interesting. It's main feature is a programmable 10 Hz to 10 MHz oscillator that's phase-locked to the 1 PPS output. They're both available at the same time (on different pins). The user manual isn't online, but I asked them via email and got a copy with no problem. The datasheets and product briefs are available at: Datasheets http://www.navsync.com/docs/CW12-TIM_DS_V1.pdf http://www.navsync.com/docs/CW25-TIM_DS_Rev_1.pdf Product Briefs http://www.navsync.com/docs/CW12_TIM.pdf http://www.navsync.com/docs/CW25_TIM.pdf I see that they're not suggesting that this little module is a full-blown GPSDO. This app note talks about it. http://www.navsync.com/docs/AN03_GPS_Timing.pdf The prices are CW12 - $89, CW25 - $64 I have no relationship to Navsync or any reseller. I'm just a potential customer. Thanks, Ed From pvince at theiet.org Thu Aug 7 05:59:09 2008 From: pvince at theiet.org (Peter Vince) Date: Thu, 7 Aug 2008 10:59:09 +0100 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: <4898D777.1030909@xtra.co.nz> References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> <4898D777.1030909@xtra.co.nz> Message-ID: Bruce wrote: >... >It may be possible to stack 3 low ESR super capacitors in series >(maximum voltage rating is around 2v -2.5V those with higher ratings are >actually series connected stacks) to do this but this is a relatively >expensive proposition. >... Presumably you would need parallel resistors to ensure an even voltage split? And if so, are we talking about kilohms or megohms? Peter From bob.paddock at gmail.com Thu Aug 7 06:28:51 2008 From: bob.paddock at gmail.com (Bob Paddock) Date: Thu, 7 Aug 2008 06:28:51 -0400 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> <4898D777.1030909@xtra.co.nz> Message-ID: On Thu, Aug 7, 2008 at 5:59 AM, Peter Vince wrote: >>It may be possible to stack 3 low ESR super capacitors in series >>(maximum voltage rating is around 2v -2.5V those with higher ratings are >>actually series connected stacks) to do this but this is a relatively >>expensive proposition. > Presumably you would need parallel resistors to ensure an even > voltage split? And if so, are we talking about kilohms or megohms? Current is probably to low for this application, but it is worth noting: LTC3225 - 150mA Supercapacitor Charger Features * Low Noise Constant Frequency Charging of Two Series Supercapacitors * Automatic Cell Balancing Prevents Capacitor Overvoltage During Charging http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1042,C1098,P84365 The part has been tested up to 400 Farads. Anyone ever look at using the LT1533 - Ultralow Noise 1A Switching Regulator as the basis of a power supply design? http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1042,C1032,P1126 -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ From bruce.griffiths at xtra.co.nz Thu Aug 7 07:25:26 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 07 Aug 2008 23:25:26 +1200 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> <4898D777.1030909@xtra.co.nz> Message-ID: <489ADBA6.3010607@xtra.co.nz> Peter Vince wrote: > Bruce wrote: > >> ... >> It may be possible to stack 3 low ESR super capacitors in series >> (maximum voltage rating is around 2v -2.5V those with higher ratings are >> actually series connected stacks) to do this but this is a relatively >> expensive proposition. >> ... >> > > Presumably you would need parallel resistors to ensure an even > voltage split? And if so, are we talking about kilohms or megohms? > > Peter > > Peter The leakage of super caps is relatively low (at least the carbon aerogell foam variety) so around 10k or so should be OK. Bruce From tractorb at ihug.co.nz Thu Aug 7 08:21:44 2008 From: tractorb at ihug.co.nz (Dave Brown) Date: Fri, 8 Aug 2008 00:21:44 +1200 Subject: [time-nuts] Power supply for Thunderbolt References: <1E16BEC392C04989AE56CFBA90971A61@APOLLO> <4898D777.1030909@xtra.co.nz> Message-ID: <098601c8f888$292461b0$7900a8c0@athlon1200> ----- Original Message ----- From: "Bruce Griffiths" To: "Discussion of precise time and frequency measurement" Sent: Wednesday, August 06, 2008 10:43 AM Subject: Re: [time-nuts] Power supply for Thunderbolt > David C. Partridge wrote: >> I'm using the Meanwell T30-B, but Tom van Baak's test on this shows >> a bit of >> phase noise at 1Hz offset which is a tad nasty: >> >> http://www.leapsecond.com/pages/tbolt/noise.htm >> >> I'm wondering if this can be reduced with a bit of extra >> de-coupling on the >> 5V supply, but haven't got round to scoping the 5V supply to see >> what >> happens every second (presumably as the output is sent to the >> serial port). >> >> Cheers >> Dave >> >> > Dave > > If phase noise at 1Hz offset is a problem you will probably need a > power supply filter with cutoff frequency well below 1Hz to make any > discernable difference. > Since the an RC filter will produce a voltage drop in the 5V supply > the > resistor value will have to be kept small and the capacitor value > correspondingly large (several farads). > It may be possible to stack 3 low ESR super capacitors in series > (maximum voltage rating is around 2v -2.5V those with higher ratings > are > actually series connected stacks) to do this but this is a > relatively > expensive proposition. > > Alternatively a modified version of the Wenzel active power supply > filter could be used if a series stack of 2 low ESR supercaps were > substituted for the capacitor connected from the supply to the > transistor base. The modified circuit stabilises the transistor's > effective emitter resistance and keeps the active filter dc current > low. > > It may also be possible to use a variation of Wenzel's opamp > augmented > active filter scheme, however the filter low frequency cutoff will > have > to be well below 1Hz for it to be effective. > > Bruce It would be interesting to see how the 'red panel' Thunderbolts (the packaged type that run from an included switching supply fed from 24 VDC) perform under a test regime such as that TVB used to compare various three rail power supplies. In 'distant past' posts, maybe 18 months back, it was suggested that this supply is a particularly good performer, but IIRC no data was supplied to support this statement. Anyone able to oblige? DaveB, NZ From jmiles at pop.net Thu Aug 7 09:21:25 2008 From: jmiles at pop.net (John Miles) Date: Thu, 7 Aug 2008 06:21:25 -0700 Subject: [time-nuts] Power supply for Thunderbolt In-Reply-To: <098601c8f888$292461b0$7900a8c0@athlon1200> Message-ID: > > It would be interesting to see how the 'red panel' Thunderbolts (the > packaged type that run from an included switching supply fed from 24 > VDC) perform under a test regime such as that TVB used to compare > various three rail power supplies. In 'distant past' posts, maybe 18 > months back, it was suggested that this supply is a particularly good > performer, but IIRC no data was supplied to support this statement. > Anyone able to oblige? This (cluttered) graph is indicative of the results I've seen. The Lucent supply used in the older red-and-black labelled Thunderbolts was not very clean, and its proximity and orientation adjacent to the Thunderbolt's PCB didn't help. Red = the new ("TAPR") Thunderbolt with my old Thunderbolt's Lucent supply Blue = the old Thunderbolt with its Lucent supply Orange = the new Thunderbolt with the supply Tom chose Purple = the old Thunderbolt with Tom's supply The reference for the red trace was somewhat noisier below 100 Hz than the one used for the others. You should assume that the red trace coincides with the orange one below 100 Hz. -- john, KE5FX -------------- next part -------------- A non-text attachment was scrubbed... Name: tbolts.gif Type: image/gif Size: 61262 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20080807/72e00701/attachment-0001.gif From w1ksz at earthlink.net Thu Aug 7 13:30:29 2008 From: w1ksz at earthlink.net (Richard W. Solomon) Date: Thu, 7 Aug 2008 10:30:29 -0700 (GMT-07:00) Subject: [time-nuts] Symmetricom Schematics Message-ID: <5271864.1218130229796.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> I have two of the TrueTime XL-AK GPS Receivers. Both came with manuals that did not include schematics. I thought I would ask Symmetricom (the now owners of TrueTime) if they would supply me with schematics. Foolish me ... They flat out refused to supply them with no explanation and no reply to any further e-Mail. We are not talking about Nuclear Weapon design here, only a GPS Receiver that is 15 (?) years old. Someone in their Corporate Office (so far unreachable) should re-think this position as it does not present them in very good light. (not to mention bad Marketing and poor press). -EOR- 73, Dick, W1KSZ From postmaster Thu Aug 7 13:36:26 2008 From: postmaster (postmaster) Date: 7 Aug 2008 18:36:26 +0100 Subject: [time-nuts] ***Your message was blocked*** Message-ID: WHAT HAPPENED ? =============== Your message "[time-nuts] Symmetricom Schematics" was not delivered. 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INTERNET HEADERS ================ X-SPF-Guess:pass (Exclaimer Mail Utilities: domain of febo.com designates 24.123.66.139 as permitted sender) client-ip=24.123.66.139; envelope-from=time-nuts-bounces+dgeoghegan=conwin.ie at febo.com; helo=febo.com; X-SPF-Result:3 X-ExAntiSpamFlags:SMTP_FROM_NOT_EQUAL_822_FROM DNSRHSBL_LISTED SPF_PASS SPF_GUESS X-ExSpamID:str=0001.0A0B0207.489B31DC.009B,ss=1,fgs=0 X-OriginalArrivalTime:07 Aug 2008 17:36:19.0984 (UTC) FILETIME=[1A581100:01C8F8B4] Return-Path:time-nuts-bounces+dgeoghegan=conwin.ie at febo.com Errors-To:time-nuts-bounces+dgeoghegan=conwin.ie at febo.com RETRY X-SA-Exim-Scanned:No (on febo.com); SAEximRunCond expanded to false X-SA-Exim-Mail-From:time-nuts-bounces at febo.com X-SA-Exim-Connect-IP:127.0.0.1 Sender:time-nuts-bounces at febo.com Content-Transfer-Encoding:7bit Content-Type:text/plain; charset="us-ascii" List-Subscribe:, List-Help: List-Post: List-Archive: List-Unsubscribe:, List-Id:Discussion of precise time and frequency measurement Reply-To:"Richard W. Solomon" , Discussion of precise time and frequency measurement Precedence:list X-Mailman-Version:2.1.9 X-BeenThere:time-nuts at febo.com Subject:[time-nuts] Symmetricom Schematics X-Spam-Level:X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00 autolearn=ham version=3.2.3 X-Spam-Checker-Version:SpamAssassin 3.2.3 (2007-08-08) on meow.febo.com X-Originating-IP:209.86.224.33 X-ELNK-Trace:a3c96698008b82d674bf435c0eb9d47857917ca117f2a1a39f4549106b00c0ae9efe4054c37f43aa350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Mailer:EarthLink Zoo Mail 1.0 Mime-Version:1.0 To:time-nuts at febo.com From:"Richard W. Solomon" Date:Thu, 7 Aug 2008 10:30:29 -0700 (GMT-07:00) PrevMsg-ID:<5271864.1218130229796.JavaMail.root at elwamui-darkeyed.atl.sa.earthlink.net> Received:from 75.164.64.103 by webmail.earthlink.net with HTTP; Thu, 7 Aug 2008 13:30:29 -0400 Received:from [209.86.224.33] (helo=elwamui-darkeyed.atl.sa.earthlink.net) by elasmtp-kukur.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1KR9Jl-0000vq-Qk for time-nuts at febo.com; Thu, 07 Aug 2008 13:30:29 -0400 Received:from elasmtp-kukur.atl.sa.earthlink.net ([209.86.89.65]) by febo.com with esmtp (Exim 4.68) (envelope-from ) id 1KR9K1-0007hm-GD for time-nuts at febo.com; Thu, 07 Aug 2008 13:30:54 -0400 Received:from localhost ([127.0.0.1] helo=febo.com ident=foobar) by febo.com with esmtp (Exim 4.68) (envelope-from ) id 1KR9KD-0007i6-QO; Thu, 07 Aug 2008 13:30:57 -0400 Received:from febo.com ([24.123.66.139]) by conwin.ie with Microsoft SMTPSVC(6.0.3790.3959); Thu, 7 Aug 2008 18:36:19 +0100 ============== END OF MESSAGE From time-nuts at kasperkp.dk Thu Aug 7 13:58:14 2008 From: time-nuts at kasperkp.dk (Kasper Pedersen) Date: Thu, 07 Aug 2008 19:58:14 +0200 Subject: [time-nuts] bounce - apologies In-Reply-To: <5271864.1218130229796.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> References: <5271864.1218130229796.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> Message-ID: <489B37B6.7080403@kasperkp.dk> I must apologize for screwing up the mail server configuration. I do not believe in generating replies to usually falsified addresses. And I'm also rather confused as to why it happened now, and not a lot earlier. To make it short, it is supposedly fixed. /Kasper Pedersen From t_list_1_only at braw.co.uk Thu Aug 7 16:50:02 2008 From: t_list_1_only at braw.co.uk (David ) Date: Thu, 7 Aug 2008 21:50:02 +0100 Subject: [time-nuts] NavSync CW12 and CW25 In-Reply-To: Message-ID: <000501c8f8cf$2b114550$0200a8c0@hp6110> Ed, I've been playing with a CW12, it basically appears to do what they say but I will not confirm any numbers for the moment, it certainly compares to my VLF derived 10MHz signals. I was looking to build a GPSDO and 10MHz from the GPS Rx seemed a better starting point than 1PPS. I'm only now near to completing part two of the exercise, phase locking a 10MHz double oven XO to the CW12 10MHz, the phase noise on the CW12 output is rather significant and needs cleaning for most applications. The ssb numbers I see from the CW12 (using an HP8560E) relative to the 10MHz carrier are : 1kHz -80 dBc/Hz 10kHz -102 dBc/Hz 100kHz -109 dBc/Hz 1MHz -126 dBc/Hz The signal is far from a pure line, close in there is a set of sidebands based on harmonics of 132 with the fundamental at -22dBc, there are various synthesis artefacts. This unit clearly needs filtering. The PLL I've built to clean it up is essentially a simple 2nd/3rd order loop with the phase comparison at 78kHz (sigs divided by 128), my model claims the 3dB closed bandwidth will be 0.3 Hz and sideband suppression about 127dB at 1kHz offset in principle. In reality I'll need to play with it to look at the real world limitations of acquisition, loop BW, analogue offsets etc . The OCXO I'm locking is a Temex part, a 'Doc1478-D" which seems to be from their S110 series. It claims to manage -145dBc at 1kHz offset. There were on ebay at low cost a while ago, everything else has largely been built from scrap which has biased the design ever so slightly, the less it costs the more amusing the project if you are not doing it for a customer. The slight disappointment has been the lack of support information about the CW12 on the web, when I spoke to them in March they said their site was going to be updated by the end of that month, clearly they have dropped the ball somewhere but the email support seems responsive. I think I've seen the CW25 appear in a recent GPSDO from Quartzlock, have a look at : http://www.quartzlock.com/cgi-bin/servepage.cgi?usr=61390&page=tech_DS_E8-X. pdf This appears to use a DDS/PLL to clean the reference clock rather than a large and expensive OCXO. Starting afresh I may have gone for the CW25 but I've got the CW12 so not thought much more about it. Regards David Mackenzie (GM4HJQ) From wje at quackers.net Thu Aug 7 21:20:47 2008 From: wje at quackers.net (wje) Date: Thu, 07 Aug 2008 21:20:47 -0400 Subject: [time-nuts] HP 5371A problem Message-ID: <489B9F6F.7020402@quackers.net> The cpu card in my 5371A seems to have died. It's asserting reset constantly, with lights 1 and 6 on. Unfortunately, my service manual doesn't include any schematics for that card. Does anyone have any suggestions? (other than doing a lot of tedious tracing) -- Bill Ezell ---------- They said 'Windows or better' so I used Linux. From vk2ihl at gmail.com Fri Aug 8 00:18:06 2008 From: vk2ihl at gmail.com (Pascal Nguyen) Date: Fri, 8 Aug 2008 14:18:06 +1000 Subject: [time-nuts] NavSync CW12 and CW25 In-Reply-To: <4899E107.7060401@sasktel.net> References: <4899E107.7060401@sasktel.net> Message-ID: <22ddffe10808072118i142373c5m2e26767deb2df3c@mail.gmail.com> Hi Ed I build a 432.424MHz and 144.424MHz beacons for radio amateur application based on CW25-TIM modules ($150 ea july-07). I cannot provide any further details than the spec published by Navsync, due to lack of measurement facility, my set up is simply a Rb standard and two RT662 HF receivers driven with 5MHz source from Rb 10MHz/2) . Audio outputs are directed to PC soundcard and water falls are visually compared, an entry level for amateur like myself. I etched the PC board for 3V3 SM power supply, backup battery, RS 232 converter (3v level) and 1PPS, NCO output, NMEA output, status LED indicators. My first board was populated with CW25 NAV, the only module available at that time, max freq 10MHz NCO. My second with CW25 TIM, max freq 30 MHz NCO Control the NCO is quite simple, via simple protocols, ie 10MHz output is such as " $PRTHS,FRQD,10.000.000 ". The CW25 TIM, factory default NCO output is 10 MHz, since startup and will lock to 1pps when status fixed, the module is running warm to touch at, I suppose an ovenised crystal is inside. I do not have the CW12, if the module is CW25TIM, it is worthy to get the CW12 to save the pain of etching a PCB. Pascal Nguyen On 8/7/08, Ed Palmer wrote: > Has anyone worked with the NavSync CW12 GPS board or the CW25 module > that its based on? It's been mentioned a few times on this mailing > list, but not really evaluated or discussed to death. :-) > > I'm looking for a new GPS board and this one looks quite interesting. > It's main feature is a programmable 10 Hz to 10 MHz oscillator that's > phase-locked to the 1 PPS output. They're both available at the same > time (on different pins). > > The user manual isn't online, but I asked them via email and got a copy > with no problem. The datasheets and product briefs are available at: > > Datasheets > http://www.navsync.com/docs/CW12-TIM_DS_V1.pdf > http://www.navsync.com/docs/CW25-TIM_DS_Rev_1.pdf > > Product Briefs > http://www.navsync.com/docs/CW12_TIM.pdf > http://www.navsync.com/docs/CW25_TIM.pdf > > I see that they're not suggesting that this little module is a > full-blown GPSDO. This app note talks about it. > > http://www.navsync.com/docs/AN03_GPS_Timing.pdf > > The prices are CW12 - $89, CW25 - $64 > > I have no relationship to Navsync or any reseller. I'm just a potential > customer. > > Thanks, > Ed > > > _______________________________________________ > time-nuts mailing list -- 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 Fri Aug 8 00:31:48 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 8 Aug 2008 06:31:48 +0200 (CEST) Subject: [time-nuts] Symmetricom Schematics In-Reply-To: <5271864.1218130229796.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink .net> References: <5271864.1218130229796.JavaMail.root@elwamui-darkeyed.atl.sa.earthlink.net> Message-ID: > I have two of the TrueTime XL-AK GPS Receivers. Both came with manuals > that did not include schematics. > I thought I would ask Symmetricom (the now owners of TrueTime) if they > would > supply me with schematics. Foolish me ... > > They flat out refused to supply them with no explanation and no reply to > any > further e-Mail. We are not talking about Nuclear Weapon design here, only > a > GPS Receiver that is 15 (?) years old. > > Someone in their Corporate Office (so far unreachable) should re-think > this > position as it does not present them in very good light. (not to mention > bad > Marketing and poor press). As a reference I have received assistance from HP/Agilent, Oscilloquartz and Pendulum when "walking in the front door" through official channels. For Symmetricom individual engineers have reached out. Last experience was Oscilloquartz that happilly scanned relevant pages on the old OSA 3210 manual to aid me in having the PSU repaired. Now that one needs trimming to lock in again. I was also given a replacement thermos for my 8600 within days, but that was maybe more of a friendly gesture, but shows the attitude. However, such friendly gestures make me feel comfortable with the company and shapes my total experience with them. HP/Agilents backlog effort on providing manuals and service manuals have been of great use and also a great source of reference. Supporting the night time hobby projects can aid in sales in the daytime activities. But if only looking at next sale, the soft issues like these gets lost. Cheers, Magnus From bruce.griffiths at xtra.co.nz Fri Aug 8 01:33:08 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 08 Aug 2008 17:33:08 +1200 Subject: [time-nuts] HP 5371A problem In-Reply-To: <489B9F6F.7020402@quackers.net> References: <489B9F6F.7020402@quackers.net> Message-ID: <489BDA94.6020506@xtra.co.nz> wje wrote: > The cpu card in my 5371A seems to have died. It's asserting reset > constantly, with lights 1 and 6 on. > > Unfortunately, my service manual doesn't include any schematics for that > card. Does anyone have any suggestions? (other than doing a lot of > tedious tracing) > > Try fig 7G8 in part 2 of the 5371A manual available on the Agilent website. Bruce From bruce.griffiths at xtra.co.nz Fri Aug 8 01:34:37 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 08 Aug 2008 17:34:37 +1200 Subject: [time-nuts] HP 5371A problem In-Reply-To: <489B9F6F.7020402@quackers.net> References: <489B9F6F.7020402@quackers.net> Message-ID: <489BDAED.3020501@xtra.co.nz> wje wrote: > The cpu card in my 5371A seems to have died. It's asserting reset > constantly, with lights 1 and 6 on. > > Unfortunately, my service manual doesn't include any schematics for that > card. Does anyone have any suggestions? (other than doing a lot of > tedious tracing) > > Correction: Figure 7G8 on page 7G17 for the processor board schematic. Bruce From j.koegel5 at gmail.com Fri Aug 8 05:06:49 2008 From: j.koegel5 at gmail.com (=?ISO-8859-1?Q?J=FCrg_K=F6gel?=) Date: Fri, 8 Aug 2008 11:06:49 +0200 Subject: [time-nuts] HP 5371A problem In-Reply-To: <489B9F6F.7020402@quackers.net> References: <489B9F6F.7020402@quackers.net> Message-ID: <390229150808080206s6262ddddw884479312a165582@mail.gmail.com> My 5372A had the same problems. Error: Contact problems in IC sockets and jumpers Remove IC and jumpers and put those back. This solved my problems Juerg From wje at quackers.net Fri Aug 8 07:03:28 2008 From: wje at quackers.net (wje) Date: Fri, 08 Aug 2008 07:03:28 -0400 Subject: [time-nuts] HP 5371A problem In-Reply-To: <489BDAED.3020501@xtra.co.nz> References: <489B9F6F.7020402@quackers.net> <489BDAED.3020501@xtra.co.nz> Message-ID: <489C2800.6050900@quackers.net> Thanks. I don't know how I missed those manuals on the Agilent site; I had looked there a while ago. Bill Ezell ---------- They said 'Windows or better' so I used Linux. Bruce Griffiths wrote: wje wrote: The cpu card in my 5371A seems to have died. It's asserting reset constantly, with lights 1 and 6 on. Unfortunately, my service manual doesn't include any schematics for that card. Does anyone have any suggestions? (other than doing a lot of tedious tracing) Correction: Figure 7G8 on page 7G17 for the processor board schematic. Bruce _______________________________________________ time-nuts mailing list -- [1]time-nuts at febo.com To unsubscribe, go to [2]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. References 1. mailto:time-nuts at febo.com 2. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts From didier at cox.net Fri Aug 8 07:53:10 2008 From: didier at cox.net (Didier Juges) Date: Fri, 8 Aug 2008 06:53:10 -0500 Subject: [time-nuts] HP 5371A problem In-Reply-To: <390229150808080206s6262ddddw884479312a165582@mail.gmail.com> References: <489B9F6F.7020402@quackers.net> <390229150808080206s6262ddddw884479312a165582@mail.gmail.com> Message-ID: <00fe01c8f94d$55369e60$04000100@didierhp> On both of my 5370As, the only way to permanently fix socket problems of that type was to replace all the sockets with gold plated, machined pin sockets. On the 5370, that was easy because the boards have relatively large holes compared to the socket pins, and there is no ground plane, so it was easy to unsolder the pins with the good desoldering tool I have access to at work. Prior to that, I had removed all chips and sprayed the sockets with DeOxIt Gold several times, but the problem always came back pretty quickly. I think it was tin wiskers. Didier > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of J?rg K?gel > Sent: Friday, August 08, 2008 4:07 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] HP 5371A problem > > My 5372A had the same problems. > Error: Contact problems in IC sockets and jumpers Remove IC > and jumpers and put those back. > This solved my problems > > Juerg > > _______________________________________________ > time-nuts mailing list -- 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 Fri Aug 8 12:08:40 2008 From: ed_palmer at sasktel.net (Ed Palmer) Date: Fri, 08 Aug 2008 10:08:40 -0600 Subject: [time-nuts] time-nuts Digest, Vol 49, Issue 12 In-Reply-To: References: Message-ID: <489C6F88.4020600@sasktel.net> > Date: Thu, 7 Aug 2008 21:50:02 +0100 > From: "David " > Subject: Re: [time-nuts] NavSync CW12 and CW25 > To: > Message-ID: <000501c8f8cf$2b114550$0200a8c0 at hp6110> > Content-Type: text/plain; charset="us-ascii" > > Ed, > > I've been playing with a CW12, it basically appears to do what they say but > I will not confirm any numbers for the moment, it certainly compares to my > VLF derived 10MHz signals. I was looking to build a GPSDO and 10MHz from the > GPS Rx seemed a better starting point than 1PPS. > My thoughts exactly. I've been playing with a Jupiter GPS board which has a 10 KHz output, but it died on me so I'm that's why I'm looking for a replacement. > I'm only now near to completing part two of the exercise, phase locking a > 10MHz double oven XO to the CW12 10MHz, the phase noise on the CW12 output > is rather significant and needs cleaning for most applications. The ssb > numbers I see from the CW12 (using an HP8560E) relative to the 10MHz carrier > are : > > 1kHz -80 dBc/Hz > 10kHz -102 dBc/Hz > 100kHz -109 dBc/Hz > 1MHz -126 dBc/Hz > > The signal is far from a pure line, close in there is a set of sidebands > based on harmonics of 132 with the fundamental at -22dBc, there are various > synthesis artefacts. This unit clearly needs filtering. > I thought it was good of Navsync to admit in the app note that their signal isn't particularly clean. I'm a rank amateur in this area, but if you changed the output frequency of the CW25 is it possible that you might find a 'sweet spot' that would give you a cleaner signal - either by matching or avoiding various harmonics of the internal clock(s)? I noticed in the datasheet that they spec the processor as 'up to 120 MHz'. If they're saying that the clock speed varies while operating then forget my question. > The PLL I've built to clean it up is essentially a simple 2nd/3rd order loop > with the phase comparison at 78kHz (sigs divided by 128), my model claims > the 3dB closed bandwidth will be 0.3 Hz and sideband suppression about 127dB > at 1kHz offset in principle. In reality I'll need to play with it to look at > the real world limitations of acquisition, loop BW, analogue offsets etc . > Did you divide down the output from the CW12? I see that you can set this frequency, but I wondered if this setting was non-volatile or if the frequency would return to 10 MHz after a loss of power. I'm assuming that the on-board battery would keep it as long as possible. > The OCXO I'm locking is a Temex part, a 'Doc1478-D" which seems to be from > their S110 series. It claims to manage -145dBc at 1kHz offset. There were on > ebay at low cost a while ago, everything else has largely been built from > scrap which has biased the design ever so slightly, the less it costs the > more amusing the project if you are not doing it for a customer. > Yeah, it's no fun to just go buy a bunch of parts. Some of my stuff looks like it came out of Dr. Frankenstein's lab. Of course, sometimes you have to dig out your wallet. I picked up a couple of those 'naked' HP Z3801a oscillators (basically HP 10811 oscillators with an second oven) that showed up on Ebay a month or so ago. I'm planning on using that for my OCXO. The 'Frankenstein' aspect will be fulfilled because I'll have to fabricate an outer casing for the oscillator and build a controller for the outer oven. > The slight disappointment has been the lack of support information about the > CW12 on the web, when I spoke to them in March they said their site was > going to be updated by the end of that month, clearly they have dropped the > ball somewhere but the email support seems responsive. I asked for the user manual in June and they responded quickly, but didn't mention anything about a website update. > I think I've seen the > CW25 appear in a recent GPSDO from Quartzlock, have a look at : > > http://www.quartzlock.com/cgi-bin/servepage.cgi?usr=61390&page=tech_DS_E8-X. > pdf > Yeah, that little module looks familiar doesn't it? The picture's not very clear, but you can just make out the Hirose connector in the corner of the module near the TNC connector. > This appears to use a DDS/PLL to clean the reference clock rather than a > large and expensive OCXO. > > Starting afresh I may have gone for the CW25 but I've got the CW12 so not > thought much more about it. > > Regards > David Mackenzie (GM4HJQ) > Thanks very much for the info, David. Ed From ed_palmer at sasktel.net Fri Aug 8 12:45:56 2008 From: ed_palmer at sasktel.net (Ed Palmer) Date: Fri, 08 Aug 2008 10:45:56 -0600 Subject: [time-nuts] NavSync CW12 and CW25 In-Reply-To: References: Message-ID: <489C7844.8010006@sasktel.net> > Date: Fri, 8 Aug 2008 14:18:06 +1000 > From: "Pascal Nguyen" > Subject: Re: [time-nuts] NavSync CW12 and CW25 > To: "Discussion of precise time and frequency measurement" > Message-ID: <22ddffe10808072118i142373c5m2e26767deb2df3c at mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > Hi Ed > I build a 432.424MHz and 144.424MHz beacons for radio amateur application > based on CW25-TIM modules ($150 ea july-07). > I cannot provide any further details than the spec published by Navsync, due > to lack of measurement facility, my set up is simply a Rb standard and two > RT662 HF receivers driven with 5MHz source from Rb 10MHz/2) . Audio outputs > are directed to PC soundcard and water falls are visually compared, an entry > level for amateur like myself. > I etched the PC board for 3V3 SM power supply, backup battery, RS 232 > converter (3v level) and 1PPS, NCO output, NMEA output, status LED > indicators. > My first board was populated with CW25 NAV, the only module available at > that time, max freq 10MHz NCO. > My second with CW25 TIM, max freq 30 MHz NCO It looks like they've dropped the CW25-NAV. It doesn't seem to be mentioned on their site. They've also reduced the output frequency on the CW25-TIM to 10 MHz. In fact, yours must be a very early model because even digging through old web pages, I can't find any mention of a 30 MHz output. Don't lose that one, you'll never find another like it! > Control the NCO is quite simple, via simple protocols, ie 10MHz output is > such as " $PRTHS,FRQD,10.000.000 ". > The CW25 TIM, factory default NCO output is 10 MHz, since startup and will > lock to 1pps when status fixed, the module is running warm to touch at, I > suppose an ovenised crystal is inside. > I do not have the CW12, if the module is CW25TIM, it is worthy to get the > CW12 to save the pain of etching a PCB. > Pascal Nguyen Thanks for the info, Ed From wje at quackers.net Fri Aug 8 13:40:37 2008 From: wje at quackers.net (wje) Date: Fri, 08 Aug 2008 13:40:37 -0400 Subject: [time-nuts] HP 5371A problem In-Reply-To: <390229150808080206s6262ddddw884479312a165582@mail.gmail.com> References: <489B9F6F.7020402@quackers.net> <390229150808080206s6262ddddw884479312a165582@mail.gmail.com> Message-ID: <489C8515.1050807@quackers.net> Thanks, all. In this case, it was a 74ALS1035 OC hex buffer that gave up the ghost. I've temporarily replaced it with 6 diodes, which works like a charm. After all, what's an OC buffer but a diode plus a little 1x gain? Bill Ezell ---------- They said 'Windows or better' so I used Linux. J?rg K?gel wrote: > My 5372A had the same problems. > Error: Contact problems in IC sockets and jumpers > Remove IC and jumpers and put those back. > This solved my problems > > Juerg > > _______________________________________________ > time-nuts mailing list -- 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 TheInfamousFlavio at hotmail.com Fri Aug 8 17:24:42 2008 From: TheInfamousFlavio at hotmail.com (TheInfamousFlavio at hotmail.com) Date: Fri, 8 Aug 2008 17:24:42 -0400 Subject: [time-nuts] Double-Oven Thunderbolt on Ebay Message-ID: Does anyone have a double-oven thunderbolt like the one that's now listed on ebay? If so, do you have any phase-noise or other performance data on it? -Flavio From jmiles at pop.net Fri Aug 8 18:23:27 2008 From: jmiles at pop.net (John Miles) Date: Fri, 8 Aug 2008 15:23:27 -0700 Subject: [time-nuts] Double-Oven Thunderbolt on Ebay In-Reply-To: Message-ID: I don't have any of the 10811-60158s, but I did buy two of the 10811-60168s that were up for auction recently. The -60168s seem to be really good performers (from memory, -106 dBc/Hz at 1 Hz, -139 at 10, -155 at 100, -164 at 1000, when I measured them against each other.) I have never seen any specs for them, or anything else about them. If someone wants to lend one of the -60158s to me, I'll benchmark it against one of the -60268s. Tom or JohnA, have either of you run any Allan plots on a 10811-60268? I'd be curious to see how they do. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of TheInfamousFlavio at hotmail.com > Sent: Friday, August 08, 2008 2:25 PM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Double-Oven Thunderbolt on Ebay > > > Does anyone have a double-oven thunderbolt like the one that's > now listed on ebay? If so, do you have any phase-noise or other > performance data on it? > > -Flavio > _______________________________________________ > time-nuts mailing list -- 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 Fri Aug 8 18:29:45 2008 From: jmiles at pop.net (John Miles) Date: Fri, 8 Aug 2008 15:29:45 -0700 Subject: [time-nuts] Double-Oven Thunderbolt on Ebay In-Reply-To: Message-ID: > Tom or JohnA, have either of you run any Allan plots on a > 10811-60268? I'd > be curious to see how they do. Er, -60168, that is. -- john, KE5FX From jra at febo.com Fri Aug 8 18:30:52 2008 From: jra at febo.com (John Ackermann N8UR) Date: Fri, 08 Aug 2008 18:30:52 -0400 Subject: [time-nuts] Double-Oven Thunderbolt on Ebay In-Reply-To: References: Message-ID: <489CC91C.3060604@febo.com> I'm measuring my pair of eBay -60158s right now and will post some results probably after the weekend. I've never seen the -60268s. One thing to note -- good phase noise and good ADEV don't necessarily go together. Case in point is the -60158s are spec'd at 1x10e-12 at 1 second, which is better than most of the 10811A variants, but the phase noise isn't as good as other versions (like the -60258 you have). John ----- John Miles said the following on 08/08/2008 06:23 PM: > I don't have any of the 10811-60158s, but I did buy two of the 10811-60168s > that were up for auction recently. The -60168s seem to be really good > performers (from memory, -106 dBc/Hz at 1 Hz, -139 at 10, -155 at 100, -164 > at 1000, when I measured them against each other.) I have never seen any > specs for them, or anything else about them. > > If someone wants to lend one of the -60158s to me, I'll benchmark it against > one of the -60268s. > > Tom or JohnA, have either of you run any Allan plots on a 10811-60268? I'd > be curious to see how they do. From richard at karlquist.com Fri Aug 8 19:02:19 2008 From: richard at karlquist.com (Rick Karlquist) Date: Fri, 8 Aug 2008 16:02:19 -0700 (PDT) Subject: [time-nuts] Double-Oven Thunderbolt on Ebay In-Reply-To: <489CC91C.3060604@febo.com> References: <489CC91C.3060604@febo.com> Message-ID: <21579.192.25.142.225.1218236539.squirrel@webmail.sonic.net> John Ackermann N8UR wrote: > > One thing to note -- good phase noise and good ADEV don't necessarily go > together. Case in point is the -60158s are spec'd at 1x10e-12 at 1 > second, which is better than most of the 10811A variants, but the phase > noise isn't as good as other versions (like the -60258 you have). > > John Yes, in fact, they have almost nothing to do with each other. Short term stability at 1 second is determined entirely by the crystal and phase noise at 1 kHz is determined almost entirely by the circuit. This is in the 10811 or any decent oscillator. Of course it is possible to use a poorly designed circuit that degrades the 1 s stability (or a really bad oven). And a crystal of much lower Q or higher intrinisic phase noise might affect phase noise. But in practice in the 10811, absent pathological corner cases, what I originally said is accuracy AFAIK. Rick Karlquist N6RK From TheInfamousFlavio at hotmail.com Fri Aug 8 19:17:11 2008 From: TheInfamousFlavio at hotmail.com (TheInfamousFlavio at hotmail.com) Date: Fri, 8 Aug 2008 19:17:11 -0400 Subject: [time-nuts] Double-Oven Thunderbolt on Ebay References: Message-ID: I was actually talking about this one... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200243779655 not the the HP double ovens. -Flavio From jmiles at pop.net Fri Aug 8 20:29:26 2008 From: jmiles at pop.net (John Miles) Date: Fri, 8 Aug 2008 17:29:26 -0700 Subject: [time-nuts] Double-Oven Thunderbolt on Ebay In-Reply-To: Message-ID: > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of TheInfamousFlavio at hotmail.com > Sent: Friday, August 08, 2008 4:17 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Double-Oven Thunderbolt on Ebay > > > I was actually talking about this one... > > http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200243779655 > > > not the the HP double ovens. Ah, sorry, my mistake; I was still thinking about those HP oscillators sold by the guy in China. I don't know about these double-oven units, but I will say that the OCXO in the TAPR Thunderbolts is extremely good, about 20 dB quieter at the 1-Hz timescale than the one in my (several-year-old) original Thunderbolt. -- john, KE5FX From louie at transsys.com Sat Aug 9 13:43:21 2008 From: louie at transsys.com (Louis Mamakos) Date: Sat, 9 Aug 2008 13:43:21 -0400 Subject: [time-nuts] The name "Totally Accurate Clock" In-Reply-To: <4898C1B7.4050004@verizon.net> References: <4898C1B7.4050004@verizon.net> Message-ID: <6C103FB8-6FE4-4EC8-9A83-2871C6D217CC@transsys.com> On Aug 5, 2008, at 5:10 PM, Tom Clark, K3IO wrote: > > My simple timing receiver was already producing sub-usec results > using > Motorola's PVT-6 "Six-Pack" 6-channel receiver, even in the face of > Selective Availability (SA). I think it was the "Six-Gun" receiver; I recall at the time while I was at U of MD, and we were doing some early NTP work, we bought a couple of PVT-6 receivers and "Six Gun" seems to ring a bell.. louie wa3ymh From jra at febo.com Sat Aug 9 16:27:59 2008 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 09 Aug 2008 16:27:59 -0400 Subject: [time-nuts] TBolt and Z3801A performance data Message-ID: <489DFDCF.8060408@febo.com> I just put the results of some tests of 2 "Time-Nuts Special" Thunderbolts, as well as 2 Z3801As, at http://www.febo.com/pages/gpsdo_comparison/ I learned an interesting (and important) lesson in doing these measurement. I initially measured the pairs of GPSDO against each other (e.g., one TBolt as "reference" and the other TBolt as "DUT"). In theory, if the two oscillators are identical, and if their noise is uncorrelated, the results of the pair can be used to deduce the results of the individual units. However, in this case doing so gave a very optimistic view -- the TBolts were better than the pair of Z3801As! Another set of measurements comparing the GPSDOs against an independent reference revealed that the first measurement was a lie. I guess you can think of it like this. Picture two OCXOs that both age at the same rate and in the same direction. Because they drift together, measuring their relative phase hides their actual drift and makes them look better than they are. On the other hand, if they were drifting in opposite directions, they would look worse than they are. An identical aging trend is a "correlation" even though it's external to the things we usually think of. John From alan.melia at btinternet.com Sat Aug 9 17:15:55 2008 From: alan.melia at btinternet.com (Alan Melia) Date: Sat, 9 Aug 2008 22:15:55 +0100 Subject: [time-nuts] GPS shielding by power lines? Message-ID: <001601c8fa65$1fc4ef20$0900a8c0@AM> Hi all, in the process of setting up a GPS time standard for a Radio Astronomy facility (amateur) we installed a GPS receiver in a small cabin with a translucent roof, thinking that would not impede the GPS signal. After a lot of head scratching as to why we were not getting the performane we got at another site, we realised that the "convenient position" for the cabin was directly below a three phase 11kV power distribution line ( common UK rural electricity distribution system). We extended the cable and moved the antenna about 20 - 30 feet to the side of the line run, which was mounted on wooden poles at about 25 feet. In this position we immediately got a reliable fix. The fix and number of usable satellites degrades as we move nearer the lines. The thought was that there as interference arcing or corona noise from the line insulators, and a receiver (AM) was deployed to listen for what was expected to be a substantial wide band noise signal....we didnt hear one! We are now confused about what the effect is. The signal could not be "screened" by the wires which are about 3 feet apart, but they definite provide a cone of interference directly under the run. The experiment was later repeated with two further different GPS receivers and produced the same result. Has anyone seen this before? have you any idea of what level noise we should be looking for? I believe this is a wide signal so maybe an AM receiver is not the best choice The area is a rural, horticultural area (called market garden in the UK) We are obviouslt concerned to trace any noise sources in the vicinity of the Hydrogen line frequency at 1420MHz. Alan G3NYK From magnus at rubidium.dyndns.org Sat Aug 9 17:28:15 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 09 Aug 2008 23:28:15 +0200 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <001601c8fa65$1fc4ef20$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM> Message-ID: <489E0BEF.3070205@rubidium.dyndns.org> Alan Melia wrote: > Hi all, in the process of setting up a GPS time standard for a Radio > Astronomy facility (amateur) we installed a GPS receiver in a small cabin > with a translucent roof, thinking that would not impede the GPS signal. > After a lot of head scratching as to why we were not getting the performane > we got at another site, we realised that the "convenient position" for the > cabin was directly below a three phase 11kV power distribution line ( common > UK rural electricity distribution system). We extended the cable and moved > the antenna about 20 - 30 feet to the side of the line run, which was > mounted on wooden poles at about 25 feet. In this position we immediately > got a reliable fix. The fix and number of usable satellites degrades as we > move nearer the lines. > > The thought was that there as interference arcing or corona noise from the > line insulators, and a receiver (AM) was deployed to listen for what was > expected to be a substantial wide band noise signal....we didnt hear one! We > are now confused about what the effect is. The signal could not be > "screened" by the wires which are about 3 feet apart, but they definite > provide a cone of interference directly under the run. The experiment was > later repeated with two further different GPS receivers and produced the > same result. > > Has anyone seen this before? have you any idea of what level noise we should > be looking for? I believe this is a wide signal so maybe an AM receiver is > not the best choice The area is a rural, horticultural area (called market > garden in the UK) We are obviouslt concerned to trace any noise sources in > the vicinity of the Hydrogen line frequency at 1420MHz. It can also be a very simple case of strong multipath causing cancelation reflections strong enought to obscure the signal. Be sure to plot signal strength and if possible delta distance from solution for each satellite along with elevation and azimuth. See if a clear pattern emerges such that certain angles is problematic. Just to make you look in another direction. Cheers, Magnus From jmiles at pop.net Sat Aug 9 17:41:45 2008 From: jmiles at pop.net (John Miles) Date: Sat, 9 Aug 2008 14:41:45 -0700 Subject: [time-nuts] TBolt and Z3801A performance data In-Reply-To: <489DFDCF.8060408@febo.com> Message-ID: These tests were made with the GPS antenna connected? At t >> 100 seconds, they should all look about the same, because that's where GPS disciplining comes in, no? They should not be uncorrelated in the long run. To the extent one Z3801 looks worse than the other at large values of tau, I'd expect there to be a good reason, like better GPS reception on one of them, or a much-worse OCXO. Measuring phase noise by comparing the two against each other should be fine, though, since their short-term drift isn't being corrected at that timescale. Your noise floor is a couple dB worse than the one I tested, but they're otherwise about the same. - john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of John Ackermann N8UR > Sent: Saturday, August 09, 2008 1:28 PM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] TBolt and Z3801A performance data > > > I just put the results of some tests of 2 "Time-Nuts Special" > Thunderbolts, as well as 2 Z3801As, at > http://www.febo.com/pages/gpsdo_comparison/ > > I learned an interesting (and important) lesson in doing these > measurement. I initially measured the pairs of GPSDO against each other > (e.g., one TBolt as "reference" and the other TBolt as "DUT"). In > theory, if the two oscillators are identical, and if their noise is > uncorrelated, the results of the pair can be used to deduce the results > of the individual units. > > However, in this case doing so gave a very optimistic view -- the TBolts > were better than the pair of Z3801As! Another set of measurements > comparing the GPSDOs against an independent reference revealed that the > first measurement was a lie. > > I guess you can think of it like this. Picture two OCXOs that both age > at the same rate and in the same direction. Because they drift > together, measuring their relative phase hides their actual drift and > makes them look better than they are. On the other hand, if they were > drifting in opposite directions, they would look worse than they are. > An identical aging trend is a "correlation" even though it's external to > the things we usually think of. > > John From pieter.ibelings at gmail.com Sat Aug 9 17:47:35 2008 From: pieter.ibelings at gmail.com (Pieter Ibelings) Date: Sat, 9 Aug 2008 17:47:35 -0400 Subject: [time-nuts] TBolt References: <489DFDCF.8060408@febo.com> Message-ID: <2CAF98B5F7044BACB9F9F317E029AEDE@xps> Hi, Where can I purchase one or two of the time-nuts Tbolt specials? Thanks, Pieter ----- Original Message ----- From: "John Ackermann N8UR" To: "Discussion of precise time and frequency measurement" Sent: Saturday, August 09, 2008 4:27 PM Subject: [time-nuts] TBolt and Z3801A performance data >I just put the results of some tests of 2 "Time-Nuts Special" > Thunderbolts, as well as 2 Z3801As, at > http://www.febo.com/pages/gpsdo_comparison/ > > I learned an interesting (and important) lesson in doing these > measurement. I initially measured the pairs of GPSDO against each other > (e.g., one TBolt as "reference" and the other TBolt as "DUT"). In > theory, if the two oscillators are identical, and if their noise is > uncorrelated, the results of the pair can be used to deduce the results > of the individual units. > > However, in this case doing so gave a very optimistic view -- the TBolts > were better than the pair of Z3801As! Another set of measurements > comparing the GPSDOs against an independent reference revealed that the > first measurement was a lie. > > I guess you can think of it like this. Picture two OCXOs that both age > at the same rate and in the same direction. Because they drift > together, measuring their relative phase hides their actual drift and > makes them look better than they are. On the other hand, if they were > drifting in opposite directions, they would look worse than they are. > An identical aging trend is a "correlation" even though it's external to > the things we usually think of. > > 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 jra at febo.com Sat Aug 9 17:48:37 2008 From: jra at febo.com (John Ackermann N8UR) Date: Sat, 09 Aug 2008 17:48:37 -0400 Subject: [time-nuts] TBolt and Z3801A performance data In-Reply-To: References: Message-ID: <489E10B5.5040104@febo.com> Yes, all were made with GPS antenna connected (and running from the same antenna via an 8-port splitter). What I was mainly commenting on is the TBolt's pronounced "hump" that shows up in the measurements against the FTS-1050A but largely disappears in the pairwise measurement. The longer tau readings are interesting mainly to see how the GPS loop kicks in; tau below about 1000 seconds seem related to OCXO performance on the TBolts, while the Z3801A seems to have a longer time constant, and somewhat more gradual attack. (By the way -- the TBolts were running with the loop parameters they were set to when I got them). John ---- John Miles said the following on 08/09/2008 05:41 PM: > These tests were made with the GPS antenna connected? At t >> 100 seconds, > they should all look about the same, because that's where GPS disciplining > comes in, no? They should not be uncorrelated in the long run. > > To the extent one Z3801 looks worse than the other at large values of tau, > I'd expect there to be a good reason, like better GPS reception on one of > them, or a much-worse OCXO. > > Measuring phase noise by comparing the two against each other should be > fine, though, since their short-term drift isn't being corrected at that > timescale. Your noise floor is a couple dB worse than the one I tested, but > they're otherwise about the same. > > - john, KE5FX > > >> -----Original Message----- >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On >> Behalf Of John Ackermann N8UR >> Sent: Saturday, August 09, 2008 1:28 PM >> To: Discussion of precise time and frequency measurement >> Subject: [time-nuts] TBolt and Z3801A performance data >> >> >> I just put the results of some tests of 2 "Time-Nuts Special" >> Thunderbolts, as well as 2 Z3801As, at >> http://www.febo.com/pages/gpsdo_comparison/ >> >> I learned an interesting (and important) lesson in doing these >> measurement. I initially measured the pairs of GPSDO against each other >> (e.g., one TBolt as "reference" and the other TBolt as "DUT"). In >> theory, if the two oscillators are identical, and if their noise is >> uncorrelated, the results of the pair can be used to deduce the results >> of the individual units. >> >> However, in this case doing so gave a very optimistic view -- the TBolts >> were better than the pair of Z3801As! Another set of measurements >> comparing the GPSDOs against an independent reference revealed that the >> first measurement was a lie. >> >> I guess you can think of it like this. Picture two OCXOs that both age >> at the same rate and in the same direction. Because they drift >> together, measuring their relative phase hides their actual drift and >> makes them look better than they are. On the other hand, if they were >> drifting in opposite directions, they would look worse than they are. >> An identical aging trend is a "correlation" even though it's external to >> the things we usually think of. >> >> 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 bg at lysator.liu.se Sat Aug 9 17:59:05 2008 From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson) Date: Sat, 09 Aug 2008 23:59:05 +0200 Subject: [time-nuts] TBolt and Z3801A performance data In-Reply-To: <489E10B5.5040104@febo.com> References: <489E10B5.5040104@febo.com> Message-ID: <1218319145.7397.114.camel@bg-desktop> Hi John, On Sat, 2008-08-09 at 17:48 -0400, John Ackermann N8UR wrote: > The longer tau readings are interesting mainly to see how the GPS loop > kicks in; tau below about 1000 seconds seem related to OCXO performance > on the TBolts, while the Z3801A seems to have a longer time constant, > and somewhat more gradual attack. (By the way -- the TBolts were > running with the loop parameters they were set to when I got them). > > John Would the fact that the bump is that "big" indicate that a more "aggressive" loop parameter setup would improve those two individual units performance? -- Bj?rn From jmiles at pop.net Sat Aug 9 18:10:56 2008 From: jmiles at pop.net (John Miles) Date: Sat, 9 Aug 2008 15:10:56 -0700 Subject: [time-nuts] TBolt and Z3801A performance data In-Reply-To: <1218319145.7397.114.camel@bg-desktop> Message-ID: > Hi John, > > On Sat, 2008-08-09 at 17:48 -0400, John Ackermann N8UR wrote: > > > The longer tau readings are interesting mainly to see how the GPS loop > > kicks in; tau below about 1000 seconds seem related to OCXO performance > > on the TBolts, while the Z3801A seems to have a longer time constant, > > and somewhat more gradual attack. (By the way -- the TBolts were > > running with the loop parameters they were set to when I got them). > > > > John > > Would the fact that the bump is that "big" indicate that a more > "aggressive" loop parameter setup would improve those two individual > units performance? It would be an interesting thing to try. The default loop bandwidth is 0.01 Hz, but since the peak of the hump is right there too, I'm not sure if GPS or the OCXO is responsible for it. The OCXO could be relatively stable at a 100-second scale but dragged around inappropriately by the GPS receiver, or the OCXO could be relatively unstable and corrected too slowly by the GPS receiver. It looks like HP uses a much lower loop bandwidth. Even so, it's interesting that we see no hint of convergence between the two GPS-locked HP oscillators at longer timescales. It's unfortunate that this kind of test takes so long to run, because it's the sort of thing you need to repeat several times to make sure you're getting at the truth of the matter. -- john, KE5FX From smace at intt.net Sat Aug 9 18:40:37 2008 From: smace at intt.net (Scott Mace) Date: Sat, 09 Aug 2008 17:40:37 -0500 Subject: [time-nuts] Thunderbolt PPS output Message-ID: <489E1CE5.3050904@intt.net> Has anyone used the thunderbolt PPS output with a N8UR FatPPS? I'm seeing a large (+-100-300us) amount of jitter on the output of the FatPPS. This same setup works fine with the input from z3801a (using a PECL/TTL converter) or the Fury (even though the Fury's pulse is wide enough to begin with). Is there something special about the thunderbolt PPS output? I noticed it seemed to require 50ohm termination to get a clean signal when I connected it to a counter (5334a) with a 3 foot cable. I'm using the FatPPS in conjunction with a soekris 4501 with the tmrin mod. Scott From didier at cox.net Sat Aug 9 19:14:59 2008 From: didier at cox.net (Didier Juges) Date: Sat, 9 Aug 2008 18:14:59 -0500 Subject: [time-nuts] Thunderbolt PPS output In-Reply-To: <489E1CE5.3050904@intt.net> References: <489E1CE5.3050904@intt.net> Message-ID: <01d001c8fa75$bf708880$04000100@didierhp> The TB's PPS output has something like 5 ohm output impedance. It is very desirable to terminate the coax cable with 50 ohm at the other end, otherwise you will get endless ringing The following web page uses the PPS output of the Thunderbolt to illustrate ringing in a non-matched cable: http://www.ko4bb.com/Test_Equipment/CoaxCableMatching.php And this page shows a minimum, energy efficient pulse stretcher: http://www.ko4bb.com/Test_Equipment/Thunderbolt/PulseStretching/ Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Scott Mace > Sent: Saturday, August 09, 2008 5:41 PM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Thunderbolt PPS output > > Has anyone used the thunderbolt PPS output with a N8UR > FatPPS? I'm seeing a large (+-100-300us) amount of jitter on > the output of the FatPPS. This same setup works fine with > the input from z3801a (using a PECL/TTL converter) or the > Fury (even though the Fury's pulse is wide enough to begin with). > Is there something special about the thunderbolt PPS output? > I noticed it seemed to require 50ohm termination to get a > clean signal when I connected it to a counter (5334a) with a > 3 foot cable. > > I'm using the FatPPS in conjunction with a soekris 4501 with > the tmrin mod. > > Scott > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. From pieter.ibelings at gmail.com Sat Aug 9 23:49:12 2008 From: pieter.ibelings at gmail.com (Pieter Ibelings) Date: Sat, 9 Aug 2008 23:49:12 -0400 Subject: [time-nuts] Z3801A References: <489E1CE5.3050904@intt.net> <01d001c8fa75$bf708880$04000100@didierhp> Message-ID: <6BAC7B1B0681496C9E011C6B43E50FE9@xps> Hi all, I am reviving an old Z3801A that was stored for 5 years. I did the RS232 header mod and I can communicate with the unit. The power LED does not come on, but I can control the enabled and active LED. I am not able to enter a date after 2007 to speed up the adquisition process. Is there a new firmware that I can load? Anyone heard of LED problems? There are no alarms in the status window. Regards, Pieter, N4IP From tractorb at ihug.co.nz Sun Aug 10 01:30:34 2008 From: tractorb at ihug.co.nz (Dave Brown) Date: Sun, 10 Aug 2008 17:30:34 +1200 Subject: [time-nuts] Power supply for Thunderbolt References: Message-ID: <014201c8faaa$387ed680$7900a8c0@athlon1200> ----- Original Message ----- From: "John Miles" To: "Discussion of precise time and frequency measurement" Sent: Friday, August 08, 2008 1:21 AM Subject: Re: [time-nuts] Power supply for Thunderbolt > >> >> It would be interesting to see how the 'red panel' Thunderbolts >> (the >> packaged type that run from an included switching supply fed from >> 24 >> VDC) perform under a test regime such as that TVB used to compare >> various three rail power supplies. In 'distant past' posts, maybe >> 18 >> months back, it was suggested that this supply is a particularly >> good >> performer, but IIRC no data was supplied to support this statement. >> Anyone able to oblige? > > This (cluttered) graph is indicative of the results I've seen. The > Lucent > supply used in the older red-and-black labelled Thunderbolts was not > very > clean, and its proximity and orientation adjacent to the > Thunderbolt's PCB > didn't help. > > Red = the new ("TAPR") Thunderbolt with my old Thunderbolt's Lucent > supply > Blue = the old Thunderbolt with its Lucent supply > Orange = the new Thunderbolt with the supply Tom chose > Purple = the old Thunderbolt with Tom's supply > > The reference for the red trace was somewhat noisier below 100 Hz > than the > one used for the others. You should assume that the red trace > coincides > with the orange one below 100 Hz. > > -- john, KE5FX Tnx John-looks like the included power supply was not a great performer in this regard. DaveB, NZ From ka2cdk at cox.net Sun Aug 10 01:38:20 2008 From: ka2cdk at cox.net (Thomas A. Frank) Date: Sun, 10 Aug 2008 01:38:20 -0400 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <001601c8fa65$1fc4ef20$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM> Message-ID: > The thought was that there as interference arcing or corona noise > from the > line insulators, and a receiver (AM) was deployed to listen for > what was > expected to be a substantial wide band noise signal....we didnt > hear one! We > are now confused about what the effect is. The signal could not be > "screened" by the wires which are about 3 feet apart, but they > definite > provide a cone of interference directly under the run. The > experiment was > later repeated with two further different GPS receivers and > produced the > same result. > > Has anyone seen this before? have you any idea of what level noise > we should > be looking for? I believe this is a wide signal so maybe an AM > receiver is > not the best choice The area is a rural, horticultural area (called > market > garden in the UK) We are obviouslt concerned to trace any noise > sources in > the vicinity of the Hydrogen line frequency at 1420MHz. > > Alan G3NYK Alan; I have no idea if this is a cause of your problem, but in some work I have done, I found that the high field strengths (electrostatic and magnetic) found under power lines can adversely effect electronic equipment that should otherwise be unaffected by the presence of power lines and their low frequency signals. I would imagine that the fields could desensitize receivers by overloading the front end amplifiers, and no amount of filtering is going to help because it is virtually impossible to shield against 50/60 Hz signals. A solid steel conduit several mm thick is only good for about 27 dB attenuation at power line frequencies. Fortunately, distance makes things better, so you may just have to move everything a bit away from the power lines. Our solution was to digitize our signals several hundred meters from the power lines and send the results digitally past them. Try getting a field strength meter (gaussmeter) and see what levels you have under the lines. Tom Frank, KA2CDK From dave.g0dja at tiscali.co.uk Sun Aug 10 03:30:11 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Sun, 10 Aug 2008 08:30:11 +0100 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <001601c8fa65$1fc4ef20$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM> Message-ID: <489E9903.90901@tiscali.co.uk> Alan Melia wrote: > Hi all, in the process of setting up a GPS time standard for a Radio > Astronomy facility (amateur) we installed a GPS receiver in a small cabin > with a translucent roof, thinking that would not impede the GPS signal. > After a lot of head scratching as to why we were not getting the performane > we got at another site, we realised that the "convenient position" for the > cabin was directly below a three phase 11kV power distribution line ( common > UK rural electricity distribution system). Since the satellite signals are in the high UHF range, arround 1575MHz, the AM receiver test is not going to tell you alot about the noise at the frequency that the GPS receiver is using. So, even if you had detected any noise from the overhead lines, it might not have been proof that this was the cause of the problems. I find that the positioning of the antenna for a GPS receiver can be very touchy. You really need a good view to the horizon and, despite what you might see on simple presentations of the satellite positions, they do tend to be mainly in the southern sky when viewed from the UK. See http://www.guralp.com/articles/20060405-howto-gps-troubleshooting/print for details. The other effect that you may notice is that your 'good' position for the antenna isn't so good all of the time as the satellites appear to move round the sky and the signal strengths from each alters. Dave (G0DJA) From alan.melia at btinternet.com Sun Aug 10 05:12:09 2008 From: alan.melia at btinternet.com (Alan Melia) Date: Sun, 10 Aug 2008 10:12:09 +0100 Subject: [time-nuts] GPS shielding by power lines? References: <001601c8fa65$1fc4ef20$0900a8c0@AM> <489E9903.90901@tiscali.co.uk> Message-ID: <003101c8facb$82f29460$0900a8c0@AM> Hi Dave, Ah I meant a 1600Mhz AM RX not a MW job the resuly is quite dramatic from seeing no usable satelites to seeing 10 to 12. The software we are running plots the tracks of the those sats seen so we can see that when seen even close to trees, foliage shielding is not a problem. I could post this plot over a number of hours it is "very pretty", and shows clearly the northerly extent of the orbits very clearly. Thanks Magnus for thoughts on further tests. We are logging the NMEA sentences so most of that detail could be available. A job for a laptop I think. Alan G3NYK ----- Original Message ----- From: "David Ackrill" To: "Discussion of precise time and frequency measurement" Sent: Sunday, August 10, 2008 8:30 AM Subject: Re: [time-nuts] GPS shielding by power lines? > Alan Melia wrote: > > Hi all, in the process of setting up a GPS time standard for a Radio > > Astronomy facility (amateur) we installed a GPS receiver in a small cabin > > with a translucent roof, thinking that would not impede the GPS signal. > > After a lot of head scratching as to why we were not getting the performane > > we got at another site, we realised that the "convenient position" for the > > cabin was directly below a three phase 11kV power distribution line ( common > > UK rural electricity distribution system). > > Since the satellite signals are in the high UHF range, arround 1575MHz, > the AM receiver test is not going to tell you alot about the noise at > the frequency that the GPS receiver is using. So, even if you had > detected any noise from the overhead lines, it might not have been proof > that this was the cause of the problems. > > I find that the positioning of the antenna for a GPS receiver can be > very touchy. You really need a good view to the horizon and, despite > what you might see on simple presentations of the satellite positions, > they do tend to be mainly in the southern sky when viewed from the UK. > > See > http://www.guralp.com/articles/20060405-howto-gps-troubleshooting/print > for details. > > The other effect that you may notice is that your 'good' position for > the antenna isn't so good all of the time as the satellites appear to > move round the sky and the signal strengths from each alters. > > Dave (G0DJA) > > _______________________________________________ > time-nuts mailing list -- 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 Sun Aug 10 05:27:31 2008 From: alan.melia at btinternet.com (Alan Melia) Date: Sun, 10 Aug 2008 10:27:31 +0100 Subject: [time-nuts] GPS shielding by power lines? References: <001601c8fa65$1fc4ef20$0900a8c0@AM> Message-ID: <003301c8facb$847319e0$0900a8c0@AM> Hi Tom Brilliant I hadnt thought of the fields actually affecting the operation of the electronics! that is certainly something that might be interesting to check. I note there lines have three "phase" feeds but no neutral wire so they must use ground as the return path to any unbalance currents.(?) Thanks Alan G3NYK ----- Original Message ----- From: "Thomas A. Frank" To: "Discussion of precise time and frequency measurement" Sent: Sunday, August 10, 2008 6:38 AM Subject: Re: [time-nuts] GPS shielding by power lines? > Alan; > > I have no idea if this is a cause of your problem, but in some work I > have done, I found that the high field strengths (electrostatic and > magnetic) found under power lines can adversely effect electronic > equipment that should otherwise be unaffected by the presence of > power lines and their low frequency signals. there. ----------snip From didier at cox.net Sun Aug 10 07:52:55 2008 From: didier at cox.net (Didier Juges) Date: Sun, 10 Aug 2008 06:52:55 -0500 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <003301c8facb$847319e0$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM> <003301c8facb$847319e0$0900a8c0@AM> Message-ID: <01f201c8fadf$a0f57130$04000100@didierhp> Alan, I don't believe you have said what type of antenna you are using. If you are using a true timing antenna (Symmetricom, Trimble Bullet) I would expect little or no direct effect from the power lines, but if you are using a puck or other inexpensive commercial antenna (which have little or no filtering or shielding), you may well be affected directly by the field from the power line on the antenna itself. The Thunderbolt itself should have enough filtering to protect you from a direct effect, the Thunderbolt has been designed to be co-located with other equipment, particularly cell transmitters, so I would expect it to be fairly immune to stray fields. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Alan Melia > Sent: Sunday, August 10, 2008 4:28 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] GPS shielding by power lines? > > Hi Tom Brilliant I hadnt thought of the fields actually > affecting the operation of the electronics! that is certainly > something that might be interesting to check. I note there > lines have three "phase" feeds but no neutral wire so they > must use ground as the return path to any unbalance > currents.(?) > > Thanks Alan G3NYK > ----- Original Message ----- > From: "Thomas A. Frank" > To: "Discussion of precise time and frequency measurement" > > Sent: Sunday, August 10, 2008 6:38 AM > Subject: Re: [time-nuts] GPS shielding by power lines? > > > > Alan; > > > > I have no idea if this is a cause of your problem, but in > some work I > > have done, I found that the high field strengths (electrostatic and > > magnetic) found under power lines can adversely effect electronic > > equipment that should otherwise be unaffected by the > presence of power > > lines and their low frequency signals. > there. > ----------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 Arnold.Tibus at gmx.de Sun Aug 10 07:53:40 2008 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Sun, 10 Aug 2008 13:53:40 +0200 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <003301c8facb$847319e0$0900a8c0@AM> Message-ID: On Sun, 10 Aug 2008 10:27:31 +0100, Alan Melia wrote: >.... I note there lines have three "phase" feeds but no >neutral wire so they must use ground as the return path to any unbalance >currents.(?) As long as the system is kept balanced a 3 phase energy transport system does not need a 4th wire as the sum of all the currents in the 3 wires (phase shift 120deg between the wires) is zero! regards Arnold, DK2WT From dave.g0dja at tiscali.co.uk Sun Aug 10 08:01:48 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Sun, 10 Aug 2008 13:01:48 +0100 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <003301c8facb$847319e0$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM> <003301c8facb$847319e0$0900a8c0@AM> Message-ID: <489ED8AC.5000903@tiscali.co.uk> Alan Melia wrote: > Hi Tom Brilliant I hadnt thought of the fields actually affecting the > operation of the electronics! that is certainly something that might be > interesting to check. I note there lines have three "phase" feeds but no > neutral wire so they must use ground as the return path to any unbalance > currents.(?) On the UK 11kV overhead network the phases are all distributed without a neutral. At the 11kV/415V transformer the HV side is delta wound and the LV is star wound, so the neutral/earth for the supply is taken from that point, not from the HV side. So, you are correct, the connection to "the general mass of earth" at the transformers is used as the return path. Which is why there are regulations about the acceptable earthing impedances at HV/LV transformers on an overhead supply. Tales of Linesmen watering earth rods to get away without having to drive in more earth rods and connect up to the transformers, and so avoid having to drive rods into hard ground, are legion in the ESI... In fact, if you look at most of the overhead high voltage distribution systems, they are all phase only, no neutral... Dave (G0DJA) From dave.g0dja at tiscali.co.uk Sun Aug 10 08:05:47 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Sun, 10 Aug 2008 13:05:47 +0100 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: References: Message-ID: <489ED99B.5020803@tiscali.co.uk> Arnold Tibus wrote: > As long as the system is kept balanced a 3 phase energy transport > system does not need a 4th wire as the sum of all the currents in the 3 wires > (phase shift 120deg between the wires) is zero! > regards > Arnold, DK2WT That is true Arnold, but in the UK (and in some other countries) we don't always have a completely balanced load. There are cases where two phase 11kV lines are run out to farms and other rural houses and, often the equipment connected at the farm/rural supplies isn't properly balanced either. The unbalanced current is connected to earth at the HV/LV transformer, as described previously. :-) Probably getting a bit OT now... Dave (G0DJA) From phk at phk.freebsd.dk Sun Aug 10 08:20:05 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 10 Aug 2008 12:20:05 +0000 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: Your message of "Sun, 10 Aug 2008 06:52:55 EST." <01f201c8fadf$a0f57130$04000100@didierhp> Message-ID: <3824.1218370805@critter.freebsd.dk> Around all high voltage lines the air is somewhat ionized and this may result in sufficient free electrons to seriously mess up the GPS signal, although I wouldn't expect much trouble from a 11kV line. The fact that the navigation message is 50Hz in the GPS signal and the power-grid in the UK is "close to 50Hz" is not a good thing in any case. -- 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 dave.g0dja at tiscali.co.uk Sun Aug 10 08:33:03 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Sun, 10 Aug 2008 13:33:03 +0100 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <3824.1218370805@critter.freebsd.dk> References: <3824.1218370805@critter.freebsd.dk> Message-ID: <489EDFFF.1050508@tiscali.co.uk> Poul-Henning Kamp wrote: > The fact that the navigation message is 50Hz in the GPS signal and > the power-grid in the UK is "close to 50Hz" is not a good thing > in any case. By UK law, it must be within +/- 1% of 50Hz. :-) Dave (G0DJA) From alan.melia at btinternet.com Sun Aug 10 09:16:31 2008 From: alan.melia at btinternet.com (Alan Melia) Date: Sun, 10 Aug 2008 14:16:31 +0100 Subject: [time-nuts] GPS shielding by power lines? References: <001601c8fa65$1fc4ef20$0900a8c0@AM><003301c8facb$847319e0$0900a8c0@AM> <01f201c8fadf$a0f57130$04000100@didierhp> Message-ID: <007f01c8faec$55aebd00$0900a8c0@AM> Hi Didier, thanks for that idea, yes they were all "pucks" all Garmin two intended for marine use and one was a old Garmin GPSIIplus with a mag "puck". I have a Trimble Palisade that I have not got round to working on yet, but I understand that there are problems putting this version into NMEA mode...so will have to be careful. Thanks Alan G3NYK ----- Original Message ----- From: "Didier Juges" To: "'Discussion of precise time and frequency measurement'" Sent: Sunday, August 10, 2008 12:52 PM Subject: Re: [time-nuts] GPS shielding by power lines? > Alan, > > I don't believe you have said what type of antenna you are using. If you are > using a true timing antenna (Symmetricom, Trimble Bullet) I would expect > little or no direct effect from the power lines, but if you are using a puck > or other inexpensive commercial antenna (which have little or no filtering > or shielding), you may well be affected directly by the field from the power > line on the antenna itself. The Thunderbolt itself should have enough > filtering to protect you from a direct effect, the Thunderbolt has been > designed to be co-located with other equipment, particularly cell > transmitters, so I would expect it to be fairly immune to stray fields. > > Didier KO4BB From dave.g0dja at tiscali.co.uk Sun Aug 10 09:37:32 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Sun, 10 Aug 2008 14:37:32 +0100 Subject: [time-nuts] Trimble Palisade (Was - GPS shielding by power lines?) In-Reply-To: <007f01c8faec$55aebd00$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM><003301c8facb$847319e0$0900a8c0@AM> <01f201c8fadf$a0f57130$04000100@didierhp> <007f01c8faec$55aebd00$0900a8c0@AM> Message-ID: <489EEF1C.10002@tiscali.co.uk> Alan Melia wrote: > Hi Didier, thanks for that idea, yes they were all "pucks" all Garmin two > intended for marine use and one was a old Garmin GPSIIplus with a mag > "puck". I have a Trimble Palisade that I have not got round to working on > yet, but I understand that there are problems putting this version into NMEA > mode...so will have to be careful. > The advice I was given when I got mine was *not* to try to put the unit into NMEA mode, as it changes the communication settings and you cannot change them back, nor can you communicate with the unit after you have done it! See http://www.dc2light.pwp.blueyonder.co.uk/Webpage/ The advice seems to be to build an additional circuit to take the output from the Palisade and convert that to NMEA. Dave (G0DJA) From phk at phk.freebsd.dk Sun Aug 10 09:46:45 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sun, 10 Aug 2008 13:46:45 +0000 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: Your message of "Sun, 10 Aug 2008 13:33:03 +0100." <489EDFFF.1050508@tiscali.co.uk> Message-ID: <4413.1218376005@critter.freebsd.dk> In message <489EDFFF.1050508 at tiscali.co.uk>, David Ackrill writes: >Poul-Henning Kamp wrote: > >> The fact that the navigation message is 50Hz in the GPS signal and >> the power-grid in the UK is "close to 50Hz" is not a good thing >> in any case. > >By UK law, it must be within +/- 1% of 50Hz. :-) Yeah, but the fact that it wanders in short time would make it an excellent frustration for GPS signal locking. -- 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 Aug 10 09:51:50 2008 From: didier at cox.net (Didier Juges) Date: Sun, 10 Aug 2008 08:51:50 -0500 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <007f01c8faec$55aebd00$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM><003301c8facb$847319e0$0900a8c0@AM><01f201c8fadf$a0f57130$04000100@didierhp> <007f01c8faec$55aebd00$0900a8c0@AM> Message-ID: <020d01c8faf0$3d979b20$04000100@didierhp> Alan, I recommend you look for an HP 58532A. I bought a brand new one on eBay for $50 BIN, sometimes you can do better. This is a good timing-grade antenna, and intended to stay outside for a long time. They have good filtering and the LNA is shielded. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Alan Melia > Sent: Sunday, August 10, 2008 8:17 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] GPS shielding by power lines? > > Hi Didier, thanks for that idea, yes they were all "pucks" > all Garmin two intended for marine use and one was a old > Garmin GPSIIplus with a mag "puck". I have a Trimble > Palisade that I have not got round to working on yet, but I > understand that there are problems putting this version into > NMEA mode...so will have to be careful. > > Thanks Alan G3NYK > > ----- Original Message ----- > From: "Didier Juges" > To: "'Discussion of precise time and frequency measurement'" > > Sent: Sunday, August 10, 2008 12:52 PM > Subject: Re: [time-nuts] GPS shielding by power lines? > > > > Alan, > > > > I don't believe you have said what type of antenna you are > using. If > > you > are > > using a true timing antenna (Symmetricom, Trimble Bullet) I would > > expect little or no direct effect from the power lines, but > if you are > > using a > puck > > or other inexpensive commercial antenna (which have little or no > > filtering or shielding), you may well be affected directly by the > > field from the > power > > line on the antenna itself. The Thunderbolt itself should > have enough > > filtering to protect you from a direct effect, the Thunderbolt has > > been designed to be co-located with other equipment, > particularly cell > > transmitters, so I would expect it to be fairly immune to > stray fields. > > > > Didier KO4BB > > > > _______________________________________________ > time-nuts mailing list -- 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 henk at deriesp.demon.nl Sun Aug 10 10:11:25 2008 From: henk at deriesp.demon.nl (Henk ten Pierick) Date: Sun, 10 Aug 2008 16:11:25 +0200 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <007f01c8faec$55aebd00$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM><003301c8facb$847319e0$0900a8c0@AM> <01f201c8fadf$a0f57130$04000100@didierhp> <007f01c8faec$55aebd00$0900a8c0@AM> Message-ID: <368A916B-C609-4BA9-99D6-10FF07152E07@deriesp.demon.nl> Hi, In car radio capacitive antennas are used. The required LNA rejection for the power line frequency is in the order of 100dB. henk On Aug 10, 2008, at 15:16, Alan Melia wrote: > Hi Didier, thanks for that idea, yes they were all "pucks" all > Garmin two > intended for marine use and one was a old Garmin GPSIIplus with a mag > "puck". I have a Trimble Palisade that I have not got round to > working on > yet, but I understand that there are problems putting this version > into NMEA > mode...so will have to be careful. > > Thanks Alan G3NYK > > ----- Original Message ----- > From: "Didier Juges" > To: "'Discussion of precise time and frequency measurement'" > > Sent: Sunday, August 10, 2008 12:52 PM > Subject: Re: [time-nuts] GPS shielding by power lines? > > >> Alan, >> >> I don't believe you have said what type of antenna you are using. >> If you > are >> using a true timing antenna (Symmetricom, Trimble Bullet) I would >> expect >> little or no direct effect from the power lines, but if you are >> using a > puck >> or other inexpensive commercial antenna (which have little or no >> filtering >> or shielding), you may well be affected directly by the field from >> the > power >> line on the antenna itself. The Thunderbolt itself should have enough >> filtering to protect you from a direct effect, the Thunderbolt has >> been >> designed to be co-located with other equipment, particularly cell >> transmitters, so I would expect it to be fairly immune to stray >> fields. >> >> Didier KO4BB > > > > _______________________________________________ > time-nuts mailing list -- 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 Sun Aug 10 14:05:22 2008 From: smace at intt.net (Scott Mace) Date: Sun, 10 Aug 2008 13:05:22 -0500 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <001601c8fa65$1fc4ef20$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM> Message-ID: <489F2DE2.6070504@intt.net> Around here they place cell antennas on a monopole down the center of power transmission line towers. The GPS antennas are invariably directly below the 100-200kv lines. The GPS signal must be reliable enough or the cell sites wouldn't be there. Scott Alan Melia wrote: > Hi all, in the process of setting up a GPS time standard for a Radio > Astronomy facility (amateur) we installed a GPS receiver in a small cabin > with a translucent roof, thinking that would not impede the GPS signal. > After a lot of head scratching as to why we were not getting the performane > we got at another site, we realised that the "convenient position" for the > cabin was directly below a three phase 11kV power distribution line ( common > UK rural electricity distribution system). We extended the cable and moved > the antenna about 20 - 30 feet to the side of the line run, which was > mounted on wooden poles at about 25 feet. In this position we immediately > got a reliable fix. The fix and number of usable satellites degrades as we > move nearer the lines. > > The thought was that there as interference arcing or corona noise from the > line insulators, and a receiver (AM) was deployed to listen for what was > expected to be a substantial wide band noise signal....we didnt hear one! We > are now confused about what the effect is. The signal could not be > "screened" by the wires which are about 3 feet apart, but they definite > provide a cone of interference directly under the run. The experiment was > later repeated with two further different GPS receivers and produced the > same result. > > Has anyone seen this before? have you any idea of what level noise we should > be looking for? I believe this is a wide signal so maybe an AM receiver is > not the best choice The area is a rural, horticultural area (called market > garden in the UK) We are obviouslt concerned to trace any noise sources in > the vicinity of the Hydrogen line frequency at 1420MHz. > > 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 Arnold.Tibus at gmx.de Sun Aug 10 16:00:57 2008 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Sun, 10 Aug 2008 22:00:57 +0200 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <489ED99B.5020803@tiscali.co.uk> Message-ID: On Sun, 10 Aug 2008 13:05:47 +0100, David Ackrill wrote: >Arnold Tibus wrote: >> As long as the system is kept balanced a 3 phase energy transport >> system does not need a 4th wire as the sum of all the currents in the 3 wires >> (phase shift 120deg between the wires) is zero! >> regards >> Arnold, DK2WT >That is true Arnold, but in the UK (and in some other countries) we >don't always have a completely balanced load. >There are cases where two phase 11kV lines are run out to farms and >other rural houses and, often the equipment connected at the farm/rural >supplies isn't properly balanced either. >The unbalanced current is connected to earth at the HV/LV transformer, >as described previously. :-) David, I agree with the a.m. unbalance, but the current should not be routed via the ground! As you say, there is a connection to ground on the Y circuit of the secondary side towards the load. From this point on there are then 4 wires in use (L1, L2, L3, N). I repeat, the return current shall not be run via ground! (At the entry of a building the neutral or return wire will be grounded to avoid voltage differences. At this point the PE will be connected as well for protection purposes.) Ground currents are in general very problematic because the resulting severe corrosion effects and noise. As I am informed, the connections of hundreds of loads will (statistically) appear more or less as balanced at the end. Eventual still existing unsymmetries are to be compensated at the medium (10 to 20 kV) to end voltage (eg. 230/400V) using distribution transformers via tricky Z-winding connections. To avoid overvoltage due to unbalance and the floating of the HV-lines, the star point of the Y transformer at one end may be grounded for ground reference, on the other side of the line a overvoltage protector will be used instead of direct grounding. Ground currents are not possible this way. To eliminate such unbalances on the HV-lines there are possibilities to compensate with special symmetry compensator devices (a kind of transformers). Sorry, this was in effect somewhat off topic, but I didn't want to leave this point uncomplete... Now to the main concern and question: I believe the problem with the 'blind' GPS system may have other reasons. 1. Due to very fast changing loads and pulse like loads (switcher etc.) there are indeed some rf on the lines. Driving partly the hv-transformers into saturation does as well result in higher frequencies (fourier). The long lines do act as antennas... 2. The high and very high voltage lines do create very strong fields up to several kV/m and some ?T! To bring this fieldstrength significantly down one shall position the antenna at least 30 to 50m away from the center line. (35 years ago I did stop with my car directly below a 380 kV line. My feet on ground standing in the open door I put my hand on top the roof of the car - wow what a strong feeling touching that big capacitor plane 1.5 m above ground! ) I am sure, the strong fields below the power lines do create some distribution current in the soil. Perhaps specially patch antennas are very susceptable to such strong fields which may upset the amplfier shifting levels...? How strong are the rf fields from these lines being perhaps a factor of several thousands below the 50 Hz field strength? regards Arnold, DK2WT From smace at intt.net Sun Aug 10 16:42:02 2008 From: smace at intt.net (Scott Mace) Date: Sun, 10 Aug 2008 15:42:02 -0500 Subject: [time-nuts] thunderbolt for ntpd or gpsd In-Reply-To: <200806151159.45824.w.knowles@xtra.co.nz> References: <200806151159.45824.w.knowles@xtra.co.nz> Message-ID: <489F529A.1030700@intt.net> ntpshm_put() needs to be called in the 0xab case as well for ntp to work. Scott --- gpsd/trunk/tsip.c 2008-08-08 23:38:27.000000000 -0500 +++ ../gpsd/trunk/tsip.c 2008-08-09 04:14:09.000000000 -0500 @@ -65,7 +65,7 @@ /* XXX clever heuristic to decide if the parity change is required. */ session->driver.tsip.parity = session->gpsdata.parity; session->driver.tsip.stopbits = session->gpsdata.stopbits; - gpsd_set_speed(session, session->gpsdata.baudrate, 'O', 1); + gpsd_set_speed(session, session->gpsdata.baudrate, 'N', 1); break; case 1: @@ -674,6 +674,10 @@ session->gpsdata.fix.time = session->gpsdata.sentence_time = gpstime_to_unix((int)s1, f1) - (double)u1; +#ifdef NTPSHM_ENABLE + if (session->context->enable_ntpshm) + (void)ntpshm_put(session,session->gpsdata.sentence_time+0.075); +#endif mask |= TIME_SET; } Wayne Knowles wrote: > Tim, Chris, > > Over a month ago I experimented with getting GPSD and the Tunderbolt working > together. > I quickly added support for the missing TSIP packet types, and was able to get > xgps to display lat, long, time and constellation status. I did manage to > get NTP to work, have not invested the time into getting the 1PPS signal > working under FreeBSD yet. > > I have attached my patches against the gpsd source repository. Note that I > did not invest much time understanding the internals of gpsd beforehand so > some aspects may not be fully implemented. > > -- > Wayne ZL2BKC > > > On Fri, Jun 13, 2008 at 8:58 AM, Christian Vogel wrote: >> gpsd: GPS Time 485697.250000 1483 14.000000 > that's encouraging > >> gpsd: Sat info: mode 1, satellites used 5: 18 9 28 15 26 > As is this. > >> gpsd: Unhandled TSIP superpacket type 0xab > > "thar's yer problem"... kinda. > > yes, we don't handle 0xAB, but that's just timing information. I see > no indication that the receiver is outputting position reports. I > should have this sorted a few hours after my Thunderbolt arrives. > Guess I need to prod the receiver into telling me where it thinks it > is. > >> Unfortunately, it does not show any information about time or position on >> a connected cgps/xgps client. >> >> Chris >> >> _______________________________________________ >> time-nuts mailing list -- 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 chris.kuethe at gmail.com Sun Aug 10 16:53:59 2008 From: chris.kuethe at gmail.com (Chris Kuethe) Date: Sun, 10 Aug 2008 13:53:59 -0700 Subject: [time-nuts] thunderbolt for ntpd or gpsd In-Reply-To: <489F529A.1030700@intt.net> References: <200806151159.45824.w.knowles@xtra.co.nz> <489F529A.1030700@intt.net> Message-ID: <91981b3e0808101353n2b6706acq61f341b2c8e23de8@mail.gmail.com> On Sun, Aug 10, 2008 at 1:42 PM, Scott Mace wrote: > ntpshm_put() needs to be called in the 0xab case as well for ntp to work. done. > --- gpsd/trunk/tsip.c 2008-08-08 23:38:27.000000000 -0500 > +++ ../gpsd/trunk/tsip.c 2008-08-09 04:14:09.000000000 -0500 > @@ -65,7 +65,7 @@ > /* XXX clever heuristic to decide if the parity change is required. > */ > session->driver.tsip.parity = session->gpsdata.parity; > session->driver.tsip.stopbits = session->gpsdata.stopbits; > - gpsd_set_speed(session, session->gpsdata.baudrate, 'O', 1); > + gpsd_set_speed(session, session->gpsdata.baudrate, 'N', 1); > break; > > case 1: not committing this - i'd prefer a heuristic to autodetect the parity. i'm open to suggestions on how to do that. > @@ -674,6 +674,10 @@ > > session->gpsdata.fix.time = session->gpsdata.sentence_time = > gpstime_to_unix((int)s1, f1) - (double)u1; > +#ifdef NTPSHM_ENABLE > + if (session->context->enable_ntpshm) > + > (void)ntpshm_put(session,session->gpsdata.sentence_time+0.075); > +#endif > mask |= TIME_SET; > } just committed this part... From lists at philpem.me.uk Sun Aug 10 17:45:13 2008 From: lists at philpem.me.uk (Philip Pemberton) Date: Sun, 10 Aug 2008 22:45:13 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO Message-ID: <489F6169.30301@philpem.me.uk> Hi folks, I've been following the mailing list for a few weeks using Pipermail (the web-based archive) and I figured now was a good time to jump in (so to speak). I'm working on a GPS-disciplined oscillator, based on a Trimble SVeeSix GPS receiver, and a homebrew OCXO. I've got a pair of 10MHz 50-degree-C oven crystals, and have a pretty good idea how to handle the temperature regulation. What I'm planning to do is mount the crystal on a copper plate with two power transistors, using heatsink compound between the copper and transistors/crystal case, and fit a temperature sensor to the top side of the crystal case. I'm planning to use a copper bracket to hold the sensor onto the crystal, and in turn mount the crystal to the copper base. As far as temperature regulation goes, I'm going to use a PIC microcontroller (one of the 8-pin chips with an A/D converter) to monitor the temperature of the crystal, and use a PID loop to control the two power transistors to maintain a temperature of 50C +/- 2 Celsius (the accuracy spec of the temperature sensor). I also have other higher-accuracy sensors (Dallas DS18S20 and DS18B20) that I can calibrate with; these are accurate to around half a degree Celsius with a resolution of 0.5C. The whole thing is going to be mounted in a metal box lined with 1/2in thick polystyrene, with all external connections made via Molex KK connectors and standard hookup wire. If there's any advantage to doing so, I might use RG174 cable for the oscillator output, but otherwise I'll stick to the KKs and maybe twist the OUT/GND wires together. What I'm stuck on is the oscillator itself. The crystals are standard parallel-resonant parts, with a load capacitance of 30 picofarads. I've got a few varicap diodes (varactors) that I'm planning to use to allow external trimming of the frequency, on top of what the ~20pf "coarse" preset will allow. So on one side of the crystal I'll have a 33pf capacitor, and on the other a 20pf load capacitor, the varicap and a low-value DC-blocking capacitor for said varicap. The standard oscillator circuit for TTL seems to be a pair of 74HC04 inverters and a few passives, or a transistor version that outputs a sine-wave. Are there any particular types of oscillator that are more suitable for high-accuracy timing? What I'd like to do is use this oscillator to calibrate frequency counters and check the calibration on oscilloscopes and similar. Being able to lock function generators (a mix of custom DDS sine generators based on Analog Devices DDS chips and FPGA-based complex-signal DDSes) against the oscillator would be very useful as well. Should I be going for a 1V sine output and then convert this to TTL in the generators (which are easy to retrofit with adapter boards) or output TTL from the reference and leave it at that? What design parameters should I be optimising for, and how? Given that a standard crystal is good to roughly 100ppm, and most commercial OCXOs are specified to be within 1x10^-9 or better, I'm aiming for around 1ppm to start with. Is even this realistic for a homebrew device? There seems to be quite a bit of difference between just building a 4MHz oscillator to run a PIC MCU to building an accurate frequency reference source... As far as parts are concerned, I'm planning to use either a BB153 or BB148 varicap, a Microchip TC1047AVNBTR temperature sensor, a National Semiconductor LM4040CIM3-4.1 voltage reference for the PIC's A/D, two BD139 power transistors and a PIC12F683 microcontroller. Thanks, -- Phil. lists at philpem.me.uk http://www.philpem.me.uk/ From bruce.griffiths at xtra.co.nz Sun Aug 10 19:35:15 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 11 Aug 2008 11:35:15 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F6169.30301@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> Message-ID: <489F7B33.9010009@xtra.co.nz> Philip Pemberton wrote: > Hi folks, > I've been following the mailing list for a few weeks using Pipermail (the > web-based archive) and I figured now was a good time to jump in (so to speak). > > I'm working on a GPS-disciplined oscillator, based on a Trimble SVeeSix GPS > receiver, and a homebrew OCXO. I've got a pair of 10MHz 50-degree-C oven > crystals, and have a pretty good idea how to handle the temperature regulation. > > What I'm planning to do is mount the crystal on a copper plate with two > power transistors, using heatsink compound between the copper and > transistors/crystal case, and fit a temperature sensor to the top side of the > crystal case. I'm planning to use a copper bracket to hold the sensor onto the > crystal, and in turn mount the crystal to the copper base. > > As far as temperature regulation goes, I'm going to use a PIC > microcontroller (one of the 8-pin chips with an A/D converter) to monitor the > temperature of the crystal, and use a PID loop to control the two power > transistors to maintain a temperature of 50C +/- 2 Celsius (the accuracy spec > of the temperature sensor). I also have other higher-accuracy sensors (Dallas > DS18S20 and DS18B20) that I can calibrate with; these are accurate to around > half a degree Celsius with a resolution of 0.5C. > > The whole thing is going to be mounted in a metal box lined with 1/2in > thick polystyrene, with all external connections made via Molex KK connectors > and standard hookup wire. If there's any advantage to doing so, I might use > RG174 cable for the oscillator output, but otherwise I'll stick to the KKs and > maybe twist the OUT/GND wires together. > > What I'm stuck on is the oscillator itself. The crystals are standard > parallel-resonant parts, with a load capacitance of 30 picofarads. I've got a > few varicap diodes (varactors) that I'm planning to use to allow external > trimming of the frequency, on top of what the ~20pf "coarse" preset will > allow. So on one side of the crystal I'll have a 33pf capacitor, and on the > other a 20pf load capacitor, the varicap and a low-value DC-blocking capacitor > for said varicap. > > The standard oscillator circuit for TTL seems to be a pair of 74HC04 > inverters and a few passives, or a transistor version that outputs a > sine-wave. Are there any particular types of oscillator that are more suitable > for high-accuracy timing? > > What I'd like to do is use this oscillator to calibrate frequency counters > and check the calibration on oscilloscopes and similar. Being able to lock > function generators (a mix of custom DDS sine generators based on Analog > Devices DDS chips and FPGA-based complex-signal DDSes) against the oscillator > would be very useful as well. Should I be going for a 1V sine output and then > convert this to TTL in the generators (which are easy to retrofit with adapter > boards) or output TTL from the reference and leave it at that? > > What design parameters should I be optimising for, and how? > > Given that a standard crystal is good to roughly 100ppm, and most > commercial OCXOs are specified to be within 1x10^-9 or better, I'm aiming for > around 1ppm to start with. Is even this realistic for a homebrew device? > > There seems to be quite a bit of difference between just building a 4MHz > oscillator to run a PIC MCU to building an accurate frequency reference source... > > As far as parts are concerned, I'm planning to use either a BB153 or BB148 > varicap, a Microchip TC1047AVNBTR temperature sensor, a National Semiconductor > LM4040CIM3-4.1 voltage reference for the PIC's A/D, two BD139 power > transistors and a PIC12F683 microcontroller. > > Thanks, > Philip If you are serious forget the fancy digital or semiconductor temperature sensors they aren't good enough. However with your crude oven structure using higher performance sensors may perhaps be unwarranted. For the best performance, unless you use a bridge oscillator circuit of some type, you will need to control the temperature of all the oscillator components as well. Its best to bond the sensor into a well drilled in the oven using non electrically conductive thermal epoxy. An analog bridge using an RTD or an NTC thermistor can have much better stability. If you use an appropriate high resolution sigma delta ADC it can reverse the bridge excitation polarity as part of the measurement sequence and give you most of the benefits of an AC bridge with fewer devices and lower cost. The next step up from the gate oscillator for fundamental crystals is perhaps Wenzel's circuit: http://www.wenzel.com/pdffiles1/pdfs/xtalosc.pdf This circuit needs a little optimisation to improve its performance. A higher base collector voltage on the oscillator transistor is desirable. This can be done using a pnp transistor to sense the oscillator transistor dc collector current and regulate it by adjusting the dc base current. Replacing the Source follower buffer with a common base transistor (allow the crystal current to flow into the emitter rather than Wenzel's shunt C) will provide higher reverse isolation. Cascade a few transformer coupled CB stages to provide gain and increased isolation. With a reverse terminated transformer coupled load in the collector of the output CB stage any load from open to short circuit can be driven without adverse effects. The inductor shown in Wenzel's circuit wont be required with your crystal either with or without a CB output stage. The limiting action occurs by cutting off the oscillator transistor during part of the cycle. The dc collector current of the oscillator transistor sets the crystal current. I would build a room temperature version first for debugging. To minimise the phase noise contributed by the varicap the EFC range should be as small as is practical. A very low noise power supply is also required for good performance. A modified version (uses 2 transistors and larger capacitors) of Wenzels active supply filter can be used to reduce the power supply noise by 30-40dB for frequencies above 1Hz or so. http://www.wenzel.com/documents/finesse.html I can provide circuit schematics if you are interested. Bruce From bruce.griffiths at xtra.co.nz Sun Aug 10 20:51:18 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Mon, 11 Aug 2008 12:51:18 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F6169.30301@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> Message-ID: <489F8D06.2020604@xtra.co.nz> Philip When using a crystal in an oven you should use a crystal specified for oven operation at a specific temperature. The crystal frequency should be specified for the desired oven temperature. For example for an AT cut crystal the crystal frequency can be approximated by as a cubic function of temperature. There are usually a couple of stationary points on the curve where the slope of frequency versus temperature is zero. The crystal should be cut so that one of these points coincides with the oven temperature as this minimises the effect of small errors in the oven temperature set point on the frequency stability. A crystal specified for non oven operation is usually cut to minimise the frequency variation over the specified range of operating temperaures. The frequency of such a crystal at one of the turning points may be several tens of ppm away from the nominal frequency. The upper turning point may not even be suitable as it may be too high or even within the expected ambient temperature range. It is also possible to cut the crystal so that the stationary points coincide at a point of inflection. In this case the frequency change corresponding to small deviations from this temperature are much smaller than those at the turning points of a conventional oven crystal. However this inflection point will lie close to room temperature for an AT cut crystal so that the "oven" will have to be cooled when the ambient temperature is above this point and heated when it is below this point. Bruce From wb6bnq at cox.net Sun Aug 10 23:26:48 2008 From: wb6bnq at cox.net (WB6BNQ) Date: Sun, 10 Aug 2008 20:26:48 -0700 Subject: [time-nuts] Designing and building an OCXO and GPSDO References: <489F6169.30301@philpem.me.uk> Message-ID: <489FB178.78A9653A@cox.net> Hello Philip, I agree with Bruce about the digital stuff and semiconductor temperature sensors, etc. From your commentary I think you should do some reading before proceeding. Here are some suggestions; The first is a series of Application notes from Agilent (old hp test div) called AN-200. A total of 5 App notes comprise the AN-200 series. If you go to the following Web page and enter AN-200 at the top of the page in the search box, you will get a return of all the AN-200 booklets in PDF that can be downloaded. The BIG one is AN-200-2, but it would be to your advantage to collect all of them. You need to paste in the entire link below if your browser doesnt see the whole thing when clicking on it. [1]http://www.home.agilent.com/agilent/facet.jspx?t=80030.k.1&cc=US&lc= eng&sm=g&pageMode=TM Next is the AN-52 series, also at the above site. The original, produced in the 1960's is AN-52. Later, in the 1970's, they rewrote and split this App note into two titled AN-52-1 & AN-52-2. There is also AN-52-4, but that does not cover your interests at the moment. I would suggest downloading ALL of them, including the original AN-52. An-52 does have historical perspective and a few things not included in the later rewrites. That should keep you busy for a while. A lot of stuff on the WEB, some good and some not so good, just take it with a grain of salt ! NIST (the old NBS) has several things worth reading, however, most of that deals with the measurement process or is a rigorous mathematical analysis of one thing or another. In my experience, an inexpensive metal can crystal and a decent oscillator circuit will hang in there under 10ppm in a regular room with a stable ambient temperature. HP used such a crystal in their 60KHz receiver because it was controlled in a loop from the 60KHz, thus approaching the accuracy and stability of the transmitted signal. Second it does not take much to get parts in 10^-7 range. Temperature compensated crystal oscillators easily handle that level. With care, a crystal oscillator in a well designed circuit can reach parts in 10^-8 with a bit-bang oven control. HP did that in the late 1950's. From that point the difficulty is logarithmic. Bill....WB6BNQ Philip Pemberton wrote: Hi folks, I've been following the mailing list for a few weeks using Pipermail (the web-based archive) and I figured now was a good time to jump in (so to speak). I'm working on a GPS-disciplined oscillator, based on a Trimble SVeeSix GPS receiver, and a homebrew OCXO. I've got a pair of 10MHz 50-degree-C oven crystals, and have a pretty good idea how to handle the temperature regulation. What I'm planning to do is mount the crystal on a copper plate with two power transistors, using heatsink compound between the copper and transistors/crystal case, and fit a temperature sensor to the top side of the crystal case. I'm planning to use a copper bracket to hold the sensor onto the crystal, and in turn mount the crystal to the copper base. As far as temperature regulation goes, I'm going to use a PIC microcontroller (one of the 8-pin chips with an A/D converter) to monitor the temperature of the crystal, and use a PID loop to control the two power transistors to maintain a temperature of 50C +/- 2 Celsius (the accuracy spec of the temperature sensor). I also have other higher-accuracy sensors (Dallas DS18S20 and DS18B20) that I can calibrate with; these are accurate to around half a degree Celsius with a resolution of 0.5C. The whole thing is going to be mounted in a metal box lined with 1/2in thick polystyrene, with all external connections made via Molex KK connectors and standard hookup wire. If there's any advantage to doing so, I might use RG174 cable for the oscillator output, but otherwise I'll stick to the KKs and maybe twist the OUT/GND wires together. What I'm stuck on is the oscillator itself. The crystals are standard parallel-resonant parts, with a load capacitance of 30 picofarads. I've got a few varicap diodes (varactors) that I'm planning to use to allow external trimming of the frequency, on top of what the ~20pf "coarse" preset will allow. So on one side of the crystal I'll have a 33pf capacitor, and on the other a 20pf load capacitor, the varicap and a low-value DC-blocking capacitor for said varicap. The standard oscillator circuit for TTL seems to be a pair of 74HC04 inverters and a few passives, or a transistor version that outputs a sine-wave. Are there any particular types of oscillator that are more suitable for high-accuracy timing? What I'd like to do is use this oscillator to calibrate frequency counters and check the calibration on oscilloscopes and similar. Being able to lock function generators (a mix of custom DDS sine generators based on Analog Devices DDS chips and FPGA-based complex-signal DDSes) against the oscillator would be very useful as well. Should I be going for a 1V sine output and then convert this to TTL in the generators (which are easy to retrofit with adapter boards) or output TTL from the reference and leave it at that? What design parameters should I be optimising for, and how? Given that a standard crystal is good to roughly 100ppm, and most commercial OCXOs are specified to be within 1x10^-9 or better, I'm aiming for around 1ppm to start with. Is even this realistic for a homebrew device? There seems to be quite a bit of difference between just building a 4MHz oscillator to run a PIC MCU to building an accurate frequency reference source... As far as parts are concerned, I'm planning to use either a BB153 or BB148 varicap, a Microchip TC1047AVNBTR temperature sensor, a National Semiconductor LM4040CIM3-4.1 voltage reference for the PIC's A/D, two BD139 power transistors and a PIC12F683 microcontroller. Thanks, -- Phil. lists at philpem.me.uk [2]http://www.philpem.me.uk/ _______________________________________________ time-nuts mailing list -- 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. http://www.home.agilent.com/agilent/facet.jspx?t=80030.k.1&cc=US&lc=eng&sm=g&pageMode=TM 2. http://www.philpem.me.uk/ 3. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts From david at endor.com Mon Aug 11 00:12:35 2008 From: david at endor.com (David McGaw) Date: Mon, 11 Aug 2008 00:12:35 -0400 Subject: [time-nuts] GPS shielding by power lines? In-Reply-To: <001601c8fa65$1fc4ef20$0900a8c0@AM> References: <001601c8fa65$1fc4ef20$0900a8c0@AM> Message-ID: <200808110414.m7B4EAIX008124@mailhub2.dartmouth.edu> You didn't say if you tried the antenna under the power lines but outside the cabin. What is translucent to light may not be to microwaves. David N1HAC At 05:15 PM 8/9/2008, you wrote: >Hi all, in the process of setting up a GPS time standard for a Radio >Astronomy facility (amateur) we installed a GPS receiver in a small cabin >with a translucent roof, thinking that would not impede the GPS signal. >After a lot of head scratching as to why we were not getting the performane >we got at another site, we realised that the "convenient position" for the >cabin was directly below a three phase 11kV power distribution line ( common >UK rural electricity distribution system). We extended the cable and moved >the antenna about 20 - 30 feet to the side of the line run, which was >mounted on wooden poles at about 25 feet. In this position we immediately >got a reliable fix. The fix and number of usable satellites degrades as we >move nearer the lines. > >The thought was that there as interference arcing or corona noise from the >line insulators, and a receiver (AM) was deployed to listen for what was >expected to be a substantial wide band noise signal....we didnt hear one! We >are now confused about what the effect is. The signal could not be >"screened" by the wires which are about 3 feet apart, but they definite >provide a cone of interference directly under the run. The experiment was >later repeated with two further different GPS receivers and produced the >same result. > >Has anyone seen this before? have you any idea of what level noise we should >be looking for? I believe this is a wide signal so maybe an AM receiver is >not the best choice The area is a rural, horticultural area (called market >garden in the UK) We are obviouslt concerned to trace any noise sources in >the vicinity of the Hydrogen line frequency at 1420MHz. > >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 bill at iaxs.net Mon Aug 11 03:11:08 2008 From: bill at iaxs.net (Bill Hawkins) Date: Mon, 11 Aug 2008 02:11:08 -0500 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F6169.30301@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> Message-ID: <001801c8fb81$6da3e670$021ba8c0@cyrus> Phil, Good on ya. When I have the time, I'll try going back to first principles. I've spent 40 years working with PID controllers and their sensors and actuators. Rule of thumb: If the transport delay (dead time between changing the heater and sensing the change) is 10% of the system time constant, you have to reduce the PID gain by about half to maintain stability (of the phase margin in a feedback loop). In your case, do NOT mount the sensor on the crystal. Mount it halfway between your heaters and expect the copper plate to come to a steady-state temperature inside the insulated cavity. Do not mount it with any form of insulating adhesive which will increase the delay. Maybe hold it down with a copper strip, like the crystal. As Bruce Griffiths suggests, use an analog sensor and a resistance bridge. Then the null signal can be digitized with low accuracy requirements, compared to digitizing the temperature to 10E-9. Mount the analog stuff in the controlled enclosure. Use fixed resistors to balance the bridge at 50C so there are no adjustments in the oven. Plan on putting the oscillator in there, too. Never mind being dead on 50C because where you want to be is on a flat spot on the temperature curve, so maybe you don't have to hold 10E-9. Your digital PID is looking at the digitized bridge error as its measurement. A setpoint can vary that error to find the flat spot. Don't forget that components and solder joints age at 50C, so plan on making adjustments once a week until the frequency stabilizes. The accuracy of the sensor is not important. What you want is precision and stability. You want the highest gain you can get in the PID, which means doing the stuff for delay as well as determining the time constant of your oven at 50C so you can set the integral term. Bill Hawkins -----Original Message----- From: Philip Pemberton Sent: Sunday, August 10, 2008 4:45 PM What I'm planning to do is mount the crystal on a copper plate with two power transistors, using heatsink compound between the copper and transistors/crystal case, and fit a temperature sensor to the top side of the crystal case. I'm planning to use a copper bracket to hold the sensor onto the crystal, and in turn mount the crystal to the copper base. As far as temperature regulation goes, I'm going to use a PIC microcontroller (one of the 8-pin chips with an A/D converter) to monitor the temperature of the crystal, and use a PID loop to control the two power transistors to maintain a temperature of 50C +/- 2 Celsius (the accuracy spec of the temperature sensor). I also have other higher-accuracy sensors (Dallas DS18S20 and DS18B20) that I can calibrate with; these are accurate to around half a degree Celsius with a resolution of 0.5C. From alan.melia at btinternet.com Mon Aug 11 06:00:03 2008 From: alan.melia at btinternet.com (Alan Melia) Date: Mon, 11 Aug 2008 11:00:03 +0100 Subject: [time-nuts] GPS shielding by power lines? References: <001601c8fa65$1fc4ef20$0900a8c0@AM> <200808110414.m7B4EAIX008124@mailhub2.dartmouth.edu> Message-ID: <004b01c8fb99$6b635860$0900a8c0@AM> Hi David yes indeed and the qualify of the fix imporves as we move away at right angles to the line....despite some trees and a tall hedge on one side. Dramatic and quite repeatable. Alan G3NYK ----- Original Message ----- From: "David McGaw" To: "Discussion of precise time and frequency measurement" Sent: Monday, August 11, 2008 5:12 AM Subject: Re: [time-nuts] GPS shielding by power lines? > You didn't say if you tried the antenna under the power lines but > outside the cabin. What is translucent to light may not be to microwaves. > > David N1HAC . From lists at philpem.me.uk Mon Aug 11 07:35:16 2008 From: lists at philpem.me.uk (Philip Pemberton) Date: Mon, 11 Aug 2008 12:35:16 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F7B33.9010009@xtra.co.nz> References: <489F6169.30301@philpem.me.uk> <489F7B33.9010009@xtra.co.nz> Message-ID: <48A023F4.10807@philpem.me.uk> Bruce Griffiths wrote: > If you are serious forget the fancy digital or semiconductor > temperature sensors they aren't good enough. I was intending to use the slow Dallas chips as a calibration reference (out-of-box they're usually quite accurate) and for testing. Is there any particular reason the analog-output (Microchip TC1047A) sensors are no good? > For the best performance, unless you use a bridge oscillator circuit > of some type, you will need to control the temperature of all the > oscillator components as well. I did have a "plan B" -- a hollow metal box with a metal sheet soldered inside at the half-way point. The crystal and oscillator circuitry would be mounted in the bottom half, and the temperature control in the top half. The temperature sensor is a three-pin SOT23 (about the size of a grain of rice) and the ground is a single pin on one side. I was thinking about mounting the sensor directly on the copper, using a small piece of Kapton tape to stop the sensor's Vout or Vcc shorting against the grounded copper sheet. That would leave two hollow air-filled cavities for the control circuitry and hold the temperature of that reasonably close to that of that of the crystal (minus a few degrees). > An analog bridge using an RTD or an NTC thermistor can have much > better stability. That sounds about right.. I was going to use a Pt100 or Pt1000 RTD, but couldn't find any decent information on them other than the resistance being 100R or 1kR at 25C -- even the manufacturer's datasheets were somewhat thin on information. > If you use an appropriate high resolution sigma delta ADC it can > reverse the bridge excitation polarity as part of the measurement > sequence and give you most of the benefits of an AC bridge with fewer > devices and lower cost. IIRC the A/D on the PIC is a 10-bit successive-approximation type with a built-in sample-and-hold (though other types have 12-bit converters). That's a measurement range of 1024 counts, which with the 4.096V reference provides a resolution of 4mV, or 1/2.5 of a degree C per count. 4V is actually the minimum reference voltage the A/D can accept. Sensor output is ((degrees_c * 10) + 500) mV. > I would build a room temperature version first for debugging. I'm planning to do that anyway. I've got a few 10MHz room-temp crystals of a similar spec to the oven crystals that I can use, and I can probably use the same parts in the prototype oven for testing. > To minimise the phase noise contributed by the varicap the EFC range > should be as small as is practical. That's the part that's going to need "a bit" of experimentation I think :) > A very low noise power supply is also required for good performance. > A modified version (uses 2 transistors and larger capacitors) of > Wenzels active supply filter can be used to reduce the power supply > noise by 30-40dB for frequencies above 1Hz or so. > http://www.wenzel.com/documents/finesse.html > > I can provide circuit schematics if you are interested. That would be great, if it's not too much trouble. Thanks, Phil. From lists at philpem.me.uk Mon Aug 11 07:38:50 2008 From: lists at philpem.me.uk (Philip Pemberton) Date: Mon, 11 Aug 2008 12:38:50 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F8D06.2020604@xtra.co.nz> References: <489F6169.30301@philpem.me.uk> <489F8D06.2020604@xtra.co.nz> Message-ID: <48A024CA.9090001@philpem.me.uk> Bruce Griffiths wrote: > When using a crystal in an oven you should use a crystal specified for > oven operation at a specific temperature. Which is what my crystal is -- a 10MHz oven crystal, specified for a 30pF load capacitance and operation at 50 degrees Celsius. I'm intending to use the oscillator at an ambient temperature of up to 35 Celsius (if it's warmer than that, then I'll likely have other things to worry about!). That's on the border of what the Agilent appnotes suggest as reasonable (15 to 20 Celsius), but still within range. In real terms, it's probably not going to see an ambient temperature higher than 25C. Well, not in this country anyway. Thanks, Phil. From bruce.griffiths at xtra.co.nz Mon Aug 11 10:09:46 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 12 Aug 2008 02:09:46 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A023F4.10807@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> <489F7B33.9010009@xtra.co.nz> <48A023F4.10807@philpem.me.uk> Message-ID: <48A0482A.40508@xtra.co.nz> Philip Pemberton wrote: > Bruce Griffiths wrote: > > If you are serious forget the fancy digital or semiconductor > > temperature sensors they aren't good enough. > > I was intending to use the slow Dallas chips as a calibration reference > (out-of-box they're usually quite accurate) and for testing. Is there > any particular reason the analog-output (Microchip TC1047A) sensors are > no good? > > You need millidegree sensistivity and stability, no sensor of this type has the required stability. Only good thermistors and RTDs approach this. > > For the best performance, unless you use a bridge oscillator circuit > > of some type, you will need to control the temperature of all the > > oscillator components as well. > > I did have a "plan B" -- a hollow metal box with a metal sheet soldered > inside at the half-way point. The crystal and oscillator circuitry would > be mounted in the bottom half, and the temperature control in the top > half. The temperature sensor is a three-pin SOT23 (about the size of a > grain of rice) and the ground is a single pin on one side. I was > thinking about mounting the sensor directly on the copper, using a small > piece of Kapton tape to stop the sensor's Vout or Vcc shorting against > the grounded copper sheet. > > That would leave two hollow air-filled cavities for the control > circuitry and hold the temperature of that reasonably close to that of > that of the crystal (minus a few degrees). > > The tempco contribution of oscillator components is such that there temperature should be stable to far better than a few degrees. Thermal gradients within the oven need to be minimised. > > An analog bridge using an RTD or an NTC thermistor can have much > > better stability. > > That sounds about right.. I was going to use a Pt100 or Pt1000 RTD, but > couldn't find any decent information on them other than the resistance > being 100R or 1kR at 25C -- even the manufacturer's datasheets were > somewhat thin on information. > > These sensors like most platinum resistance thermometers elements have a tempco of about 3900 ppm/K or so. Copper resistors have also be used for this purpose and have a similar tempco. Thermistors are much more sensitive to temperature and high quality ones are almost as stable. The output from a bridge using RTDs is relatively low and precautions have to be taken to eliminate thermocouple effects as well as amplifier offsets. An AC bridge excitation technique or periodically reversing the bridge excitation polarity can help. > > If you use an appropriate high resolution sigma delta ADC it can > > reverse the bridge excitation polarity as part of the measurement > > sequence and give you most of the benefits of an AC bridge with fewer > > devices and lower cost. > > IIRC the A/D on the PIC is a 10-bit successive-approximation type with a > built-in sample-and-hold (though other types have 12-bit converters). > > That's a measurement range of 1024 counts, which with the 4.096V > reference provides a resolution of 4mV, or 1/2.5 of a degree C per > count. 4V is actually the minimum reference voltage the A/D can accept. > > Insufficient resolution you need a least count below 0.001C. If you use that ADC it will need a suitable preamp. However a linear range of a little less than 1C is sufficient. A high resolution sigma delta ADC is probably a better choice as a low drift preamp isnt required. The output DAC (of whatever type) needs to be monotonic and have high resolution (18 bits or more) to allow the temperature to be controlled to better than 0.001C. There are several techniques for achieving more resolution from a low resolution DAC. > Sensor output is ((degrees_c * 10) + 500) mV. > > > I would build a room temperature version first for debugging. > > I'm planning to do that anyway. I've got a few 10MHz room-temp crystals > of a similar spec to the oven crystals that I can use, and I can > probably use the same parts in the prototype oven for testing. > > > To minimise the phase noise contributed by the varicap the EFC range > > should be as small as is practical. > > That's the part that's going to need "a bit" of experimentation I think :) > > If you use a manual trimmer as well then a range of 1E-7 or so is usually sufficient. If all frequency adjustment is via EFC then you need to accommodate at least 10 years worth of aging. > > A very low noise power supply is also required for good performance. > > A modified version (uses 2 transistors and larger capacitors) of > > Wenzels active supply filter can be used to reduce the power supply > > noise by 30-40dB for frequencies above 1Hz or so. > > http://www.wenzel.com/documents/finesse.html > > > > I can provide circuit schematics if you are interested. > > That would be great, if it's not too much trouble. > > Thanks, > Phil. > What are the crystal parameters: Q? ESR? L? Cshunt? Cseries? What crystal cut is used AT?, BT?, SC? Is it a fundamental crystal? Will post the modified P/S filter in a few hours together with the modified Wenzel low noise oscillator circuit. If you are using an overtone crystal or an SC crystal then provisions need to be made to suppress unwanted modes. In this case a somewhat different oscillator configuration is perhaps advisable. Something like one of the Driscoll type oscillators which have a tuned tank for mode suppression can be used. Otherwise a somewhat more complex oscillator with AGC may be necessary. Bruce From holrum at hotmail.com Mon Aug 11 12:56:43 2008 From: holrum at hotmail.com (Mark Sims) Date: Mon, 11 Aug 2008 16:56:43 +0000 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: For your temperature sensor and/or ADC consider the Analog Devices AD537 voltage to frequency converter chip. It has an onboard temperature sensor or could be interfaced to a thermistor, etc. The on chip sensor has a fairly large thermal mass. If you need instantaneous response to temperature use a very small thermistor. Since the output is frequency, any time nut worth his/her/its salt should be able to come up with a suitable counter circuit. One system that I did had the V/F freq set around 200 Hz. Counting a 16 MHz clock over 256 cycles of V/F waveform yielded microdegree resolution. ---------------------------------------- _________________________________________________________________ Get more from your digital life. Find out how. http://www.windowslive.com/default.html?ocid=TXT_TAGLM_WL_Home2_082008 From david.partridge at dsl.pipex.com Mon Aug 11 13:42:59 2008 From: david.partridge at dsl.pipex.com (David C. Partridge) Date: Mon, 11 Aug 2008 18:42:59 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F6169.30301@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> Message-ID: <93BED0F385694691BE930F8A55EAB705@APOLLO> Stupid question - why build your own OCXO when you can buy a pretty good Oscilloquartz OCXO from eBay item number 300247357254 for almost a song? Yes I know - it's fun! Dave From lists at philpem.me.uk Mon Aug 11 16:25:29 2008 From: lists at philpem.me.uk (Philip Pemberton) Date: Mon, 11 Aug 2008 21:25:29 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <93BED0F385694691BE930F8A55EAB705@APOLLO> References: <489F6169.30301@philpem.me.uk> <93BED0F385694691BE930F8A55EAB705@APOLLO> Message-ID: <48A0A039.8080503@philpem.me.uk> David C. Partridge wrote: > Stupid question - why build your own OCXO when you can buy a pretty good > Oscilloquartz OCXO from eBay item number 300247357254 for almost a song? I can think of a couple of reasons: 1) If it breaks, I can rip it open, poke and probe it, figure out what's wrong and then hopefully fix it. I've got loads of T&M gear that sadly never sees the use it should -- a very nice Tek TDS2024B DSO that's been used maybe a dozen times, a HP 1651B logic analyser that's been used about as much (but bought second-hand with severe screen burn), the list goes on. 2) It's nice to know how things work - I have a severe case of blackboxophobia. I hate little black boxes that do magic things, and have zero parts availability. This has gotten to the point where I've built a model logic analyser to learn how they work, and most of my complex signal generators are homebrew too. I've got a nice DDS signal generator that I'm working on at the moment, which should by virtue of the ADI DDS chip be able to do AM, FM, BPSK, QPSK, (maybe) 8PSK and a few other modulation modes. I'm building it for... testing a Radio 4 timecode receiver. Bonus points if I can make it produce DVB-S compliant streams at 70MHz IF and upconvert to 1.x GHz L-band to test satellite receivers. That's quite far down on the projects list though :) 3) I try and avoid ebay where possible. I've had pretty good luck with UK and US sellers, but the few I've dealt with from other countries have been horrendous, especially those in the vicinity of China and Hong Kong. Six months for one parcel to arrive... Anyone here listen to the "SolderSmoke" podcast? #72 pretty much sums it up. I like to know what things do, and I can't stand to buy something if I can build it from parts I've got in my junk box. In my weird world, if I've already bought the parts, then effectively my cost is zero.. I've got the bits, I might as well use them. Plus I was actually looking at new OCXOs -- at the time I decided to do this, there weren't any on eBay. The lowest quote I got was ?132 +VAT (rounded up from the quote I just dug out...) for a 12V, fairly low-tech OCXO. The shiny new high-tech one with the TTL status output and other stuff was about ?240 and some change. In effect, it's cost me ?37 for the crystals, and ~?10 for a dozen each of the temperature sensors and voltage references. I'm still below half the cost of a brand-new commercial OCXO. > Yes I know - it's fun! And it's fun. That too. :) Thanks, -- Phil. lists at philpem.me.uk http://www.philpem.me.uk/ From lists at philpem.me.uk Mon Aug 11 16:28:28 2008 From: lists at philpem.me.uk (Philip Pemberton) Date: Mon, 11 Aug 2008 21:28:28 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489FB178.78A9653A@cox.net> References: <489F6169.30301@philpem.me.uk> <489FB178.78A9653A@cox.net> Message-ID: <48A0A0EC.8080003@philpem.me.uk> WB6BNQ wrote: > The first is a series of Application notes from Agilent (old hp test > div) called AN-200. A total of 5 App notes comprise the AN-200 series. > If you go to the following Web page and enter AN-200 at the top of the > page in the search box, you will get a return of all the AN-200 booklets > in PDF that can be downloaded. The BIG one is AN-200-2, but it would be > to your advantage to collect all of them. You need to paste in the > entire link below if your browser doesn't see the whole thing when > clicking on it. Hm, nothing found on Agilent's site, but Google found it (search term: "agilent.com AN-200"). Lots of interesting stuff there, from quartz oscillator basics through microwave signal generation and measurement... > That should keep you busy for a while. A lot of stuff on the WEB, some > good and some not so good, just take it with a grain of salt ! NIST > (the old NBS) has several things worth reading, however, most of that > deals with the measurement process or is a rigorous mathematical > analysis of one thing or another. Well I was looking at the manual for the ELV OCXO400 (http://www.elv-downloads.de/service/manuals/OCXO400/OCXO400_KM_G_010502.pdf) as a partial reference, and the disassembly photos for one of the HP dual-oven oscillators (can't find the link at the moment). I dismissed the ELV's mechanical design based on the fact that it was two BC337 (read: low power) transistors mounted on each side of the crystal, with a cheap thermistor on top. No real thermal load at all -- as soon as the transistors turn on, the temperature is likely to shoot WAY, WAY up, then drop FAST when the transistors are turned off. The comparator-based thermostat-type temperature control isn't likely to make that much easier either. Apparently the oscillator circuit is quite badly designed too (based on information at http://glowbug.nl/projects/M51.html). Badly biased output transistors and mismatched xtal load capacitance mainly. > Second it does not take much to get parts in 10^-7 range. Temperature > compensated crystal oscillators easily handle that level. With care, a > crystal oscillator in a well designed circuit can reach parts in 10^-8 > with a bit-bang oven control. HP did that in the late 1950's. From > that point the difficulty is logarithmic. It certainly seems that way... Nice to know it's not quite as hard as it looks. The ELV is specced at 2x10^-8 stability and uses an AT-cut HC49U fundamental-mode parallel-resonant crystal. I don't have the specs for the crystal cut used for my 10MHz xtals, but I do know the base specifications are almost identical to the ELV unit's crystal. I should probably mention the main reason I wanted to use the PIC control -- so I can adjust the oven parameters (desired temperature, PID variables, and so on) in real time, and read off the oven status at the same time (current temperature, target temperature, last warmup time, hours run since last power cycle, total crystal age, starting temperature, crystal oscillator state, and so on). Obviously the turning point for each crystal isn't going to be exactly 50.0000000... Celsius, so being able to hook up a high-resolution counter and figure out what the exact turning point is and program the thermal management kit with that would be useful. In truth this is more a research and learning exercise. It'd just be nice to end up with something that compares reasonably well to a commercial OCXO, that I can use as a basic frequency reference. Then later on I'll decide if I really need anything better. Thanks, -- Phil. lists at philpem.me.uk http://www.philpem.me.uk/ From connie.marshall at suddenlink.net Mon Aug 11 18:08:30 2008 From: connie.marshall at suddenlink.net (Connie Marshall) Date: Mon, 11 Aug 2008 17:08:30 -0500 Subject: [time-nuts] TBolt and Z3801A performance data In-Reply-To: <489DFDCF.8060408@febo.com> Message-ID: Thanks John... good report! 73 Connie -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On Behalf Of John Ackermann N8UR Sent: Saturday, August 09, 2008 3:28 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] TBolt and Z3801A performance data I just put the results of some tests of 2 "Time-Nuts Special" Thunderbolts, as well as 2 Z3801As, at http://www.febo.com/pages/gpsdo_comparison/ I learned an interesting (and important) lesson in doing these measurement. I initially measured the pairs of GPSDO against each other (e.g., one TBolt as "reference" and the other TBolt as "DUT"). In theory, if the two oscillators are identical, and if their noise is uncorrelated, the results of the pair can be used to deduce the results of the individual units. However, in this case doing so gave a very optimistic view -- the TBolts were better than the pair of Z3801As! Another set of measurements comparing the GPSDOs against an independent reference revealed that the first measurement was a lie. I guess you can think of it like this. Picture two OCXOs that both age at the same rate and in the same direction. Because they drift together, measuring their relative phase hides their actual drift and makes them look better than they are. On the other hand, if they were drifting in opposite directions, they would look worse than they are. An identical aging trend is a "correlation" even though it's external to the things we usually think of. 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 bruce.griffiths at xtra.co.nz Mon Aug 11 19:28:48 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 12 Aug 2008 11:28:48 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A0A0EC.8080003@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> <489FB178.78A9653A@cox.net> <48A0A0EC.8080003@philpem.me.uk> Message-ID: <48A0CB30.5010002@xtra.co.nz> Philip > I dismissed the ELV's mechanical design based on the fact that it was two > BC337 (read: low power) transistors mounted on each side of the crystal, with > a cheap thermistor on top. No real thermal load at all -- as soon as the > transistors turn on, the temperature is likely to shoot WAY, WAY up, then > drop FAST when the transistors are turned off. The comparator-based > thermostat-type temperature control isn't likely to make that much easier > either. > > Thermal gradients in the vicinity of the crystal will be quite high. > Apparently the oscillator circuit is quite badly designed too (based on > information at http://glowbug.nl/projects/M51.html). Badly biased output > transistors and mismatched xtal load capacitance mainly. > Not to mention the low isolation buffer amplifier with relatively high phase noise. Extracting the signal through the crystal is a good method for ensuring a low phase noise floor. Ignore the misguided comments in the literature and on the web that say otherwise. Their calculations indicate a phase noise floor 20dB or more higher than that achieved in practice. This is the result of applying an standard equation to a situation where the assumptions implicit in its derivation don't hold. > > Second it does not take much to get parts in 10^-7 range. Temperature > > compensated crystal oscillators easily handle that level. With care, a > > crystal oscillator in a well designed circuit can reach parts in 10^-8 > > with a bit-bang oven control. HP did that in the late 1950's. From > > that point the difficulty is logarithmic. > > It certainly seems that way... > Nice to know it's not quite as hard as it looks. The ELV is specced at > 2x10^-8 stability and uses an AT-cut HC49U fundamental-mode parallel-resonant > crystal. I don't have the specs for the crystal cut used for my 10MHz xtals, > but I do know the base specifications are almost identical to the ELV unit's > crystal. > > I should probably mention the main reason I wanted to use the PIC control -- > so I can adjust the oven parameters (desired temperature, PID variables, and > so on) in real time, and read off the oven status at the same time (current > temperature, target temperature, last warmup time, hours run since last power > cycle, total crystal age, starting temperature, crystal oscillator state, and > so on). Obviously the turning point for each crystal isn't going to be > exactly 50.0000000... Celsius, so being able to hook up a high-resolution > counter and figure out what the exact turning point is and program the > thermal management kit with that would be useful. > > You'll need a really stable reference for the counter to get close to the turning point. Don't ramp the temperature too quickly as AT crystals are also sensitive to thermal transients. > In truth this is more a research and learning exercise. It'd just be nice to > end up with something that compares reasonably well to a commercial OCXO, > that I can use as a basic frequency reference. Then later on I'll decide if I > really need anything better. > > Thanks, > Bruce From bruce.griffiths at xtra.co.nz Mon Aug 11 19:33:28 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 12 Aug 2008 11:33:28 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: <48A0CC48.1000100@xtra.co.nz> Mark Sims wrote: > For your temperature sensor and/or ADC consider the Analog Devices AD537 voltage to frequency converter chip. It has an onboard temperature sensor or could be interfaced to a thermistor, etc. The on chip sensor has a fairly large thermal mass. If you need instantaneous response to temperature use a very small thermistor. > > Since the output is frequency, any time nut worth his/her/its salt should be able to come up with a suitable counter circuit. One system that I did had the V/F freq set around 200 Hz. Counting a 16 MHz clock over 256 cycles of V/F waveform yielded microdegree resolution. > ---------------------------------------- > > Mark The AD537 has too much drift and too little sensitivity to reliably maintain the oven temperature (at the sensor) to within a few millidegrees. The internal dissipation of other circuitry within the chip will increase the sensor temperature offset from the temperature being measured. A thermistor bridge is a better idea as it can have high stability and sensitivity (about 10x that of an RTD). Bruce From holrum at hotmail.com Mon Aug 11 20:40:13 2008 From: holrum at hotmail.com (Mark Sims) Date: Tue, 12 Aug 2008 00:40:13 +0000 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: What you can do is calibrate the AD537/sensor(if used)/freq counter as a unit. Things like temperature offsets, chip dissipations, oscillator shifts, component tempcos, widget wiggles, etc. get compensated for. Ideally in an ocxo you would want the sensor and freq counter in the oven (or at least the freq counter reference oscillator). Hmmm, could get wickedly interesting if you clocked the freq counter with the OCXO output you were controlling. In one system we used a 20th order polynomial to do the conversion from reading to temperature. After a couple of years in the field (actually under the field) they retrieved, the data was dumped, and a new calibrations were done. The calibrations had typically shifted less than 100 microdegrees... and that was with a crappy oscillator in the freq counter. As far as sensitivity... a lower res unit (around 0.01 degree resolution) could easily detect the body heat from people in the lab. From temperature gradients you could reliably count people entering and leaving (a couple of particularly ample people counted as two bodies). ---------------------------------------- The AD537 has too much drift and too little sensitivity to reliably maintain the oven temperature (at the sensor) to within a few millidegrees. The internal dissipation of other circuitry within the chip will increase the sensor temperature offset from the temperature being measured. A thermistor bridge is a better idea as it can have high stability and sensitivity (about 10x that of an RTD). _________________________________________________________________ Get more from your digital life. Find out how. http://www.windowslive.com/default.html?ocid=TXT_TAGLM_WL_Home2_082008 From dforbes at dakotacom.net Mon Aug 11 22:06:00 2008 From: dforbes at dakotacom.net (David Forbes) Date: Mon, 11 Aug 2008 19:06:00 -0700 Subject: [time-nuts] Seriously vintage time nut Message-ID: Here's a fellow using a BIG tuning fork frequency standard in 1929 for some industrial data acquisition system using 16mm movie film as the medium... http://www.shorpy.com/node/4218?size=_original Then feel free to look at all the photos on the site - they're fascinating. -- --David Forbes, Tucson, AZ http://www.cathodecorner.com/ From bill at iaxs.net Tue Aug 12 00:42:16 2008 From: bill at iaxs.net (Bill Hawkins) Date: Mon, 11 Aug 2008 23:42:16 -0500 Subject: [time-nuts] Seriously vintage time nut In-Reply-To: References: Message-ID: <002201c8fc35$cbef1a10$021ba8c0@cyrus> Looks like a straight 8 gas engine on the stand. Hard to tell scaling from the hand. The hand looks graceful, like a woman's hand. So, why is the big vibrating apparatus not level? Looks like it has a granite block supported by four flat springs inside the box. Sure is nice to be reminded of the early days of technology when most of this list is about bleeding edge stuff. Bill Hawkins -----Original Message----- From: David Forbes Sent: Monday, August 11, 2008 9:06 PM Here's a fellow using a BIG tuning fork frequency standard in 1929 for some industrial data acquisition system using 16mm movie film as the medium... http://www.shorpy.com/node/4218?size=_original Then feel free to look at all the photos on the site - they're fascinating. -- From bruce.griffiths at xtra.co.nz Tue Aug 12 02:06:58 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Tue, 12 Aug 2008 18:06:58 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F6169.30301@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> Message-ID: <48A12882.3000205@xtra.co.nz> Philip The attached circuit schematic is for a 10MHz oscillator using a fundamental mode AT cut crystal. The problem with using a common base buffer with a fundamental mode crystal is that the crystal ESR is rather low so that the real component of the CB stage input impedance is not much less than that of the crystal. This reduces the crystal loaded Q significantly unless the common base stage is run at a high collector current which increases the CB stage output current noise. The crystal buffer shown here (Q103+Q104) reduces the real part of the input buffer stage input impedance to a value much less than the ESR of the crystal without using a large collector current. The oscillator transistor is in a Colpitts configuration. The transistor is only on for part of the cycle. The resistor (R102) connected between the emitter and C101+C102 junction reduces the phase noise of Q101 when it is on. The crystal current is determined by the dc collector current of Q101 and can be varied by adjusting R103. R103 is adjusted to set the crystal current to about 1.8mA (+13dBm output in a 50 ohm load.) The output stage uses an 18V supply so that it can drive an open circuit load without saturating the output transistor. This supply voltage can be reduced if a differential CB output stage is used OR 1) The output device is allowed to saturate when driving a high impedance load 2) The output transformer turns ratio is reduced 3) A lower output than +13dBm is acceptable. Since the phase noise floor is determined by the phase noise floor of the buffer amplifier some care has been taken to ensure that the buffer amplifier phase noise floor is low. Power supply noise will increase the phase noise of the amplifier and oscillator so a low noise power supply is essential. At low offset frequencies the crystal and the oscillator stage start to contribute to the phase noise. Thus the oscillator phase noise also needs to be low for low phase noise close to the carrier. It can be advantageous to use transistors with low collector base capacitances as their PM and AM noise can be made very low with RF feedback. The major source of flicker PM and flicker AM noise in an amplifier is modulation of the various device capacitances by low frequency noise currents or voltages. Thus low noise power supplies and low noise components should be used. Only use metal film or thin film resistors. No thick film, carbon resistor, metal oxide resistor should be used as they have significant flicker noise when a dc current is flowing through them. All coupling caps should be NP0/C0G or equivalent. Bruce -------------- next part -------------- A non-text attachment was scrubbed... Name: OCXO.gif Type: image/gif Size: 48363 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20080812/7fa8dc71/attachment-0001.gif From hmurray at megapathdsl.net Tue Aug 12 14:36:57 2008 From: hmurray at megapathdsl.net (Hal Murray) Date: Tue, 12 Aug 2008 11:36:57 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge Message-ID: <20080812183658.C1D36BCCB@ip-64-139-1-69.sjc.megapath.net> I've got a couple of GPS units that use the SiRF chips feeding NTP. I was looking for low cost units for time keeping. They don't work very well. The time offset of the NMEA message wanders/jitters by about 100 ms. I can easily correct for a constant offset, but I can't dance around an offset that won't hold still. (Oh, well. I tried.) But I still have a couple of them collecting data. They seem to get confused by leap seconds. At least that's the only thing I can think of that changed recently. Here is a graph: http://www.megapathdsl.net/~hmurray/ntp/leap-gps3.gif It started, midnight, July 31. Does anybody know when the leap second announcement hit the satellites? I assume it's a software bug. Looks like it repeats on a weekly pattern. The red line on the top is a sane unit used as a reference to show that the time on the local system time isn't bouncing around. Here is a longer time span that shows a hanging bridge type pattern on the offset: http://www.megapathdsl.net/~hmurray/ntp/leap-gps2.gif If you were (un)lucky, you could get fooled into thinking that the offset was reasonably stable. This graph includes a few more units: http://www.megapathdsl.net/~hmurray/ntp/leap-gps.gif The spikes on the blue Garmin GPS 18 LVC usually happen when it is recovering from not-enough satellites. (I haven't checked these particular samples. That's what I found the last time I investigated.) -- These are my opinions, not necessarily my employer's. I hate spam. From chris.kuethe at gmail.com Tue Aug 12 15:03:47 2008 From: chris.kuethe at gmail.com (Chris Kuethe) Date: Tue, 12 Aug 2008 12:03:47 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: <20080812183658.C1D36BCCB@ip-64-139-1-69.sjc.megapath.net> References: <20080812183658.C1D36BCCB@ip-64-139-1-69.sjc.megapath.net> Message-ID: <91981b3e0808121203m5a7da16y70988f4eb31a4e5d@mail.gmail.com> On Tue, Aug 12, 2008 at 11:36 AM, Hal Murray wrote: > > I've got a couple of GPS units that use the SiRF chips feeding NTP. I was > looking for low cost units for time keeping. They don't work very well. The > time offset of the NMEA message wanders/jitters by about 100 ms. I can > easily correct for a constant offset, but I can't dance around an offset that > won't hold still. (Oh, well. I tried.) Yep, that's to be expected, given the iterative solver they're using. Try turning on the ZDA message, apparently the $ sign is aligned to the start of the second ... if its implemented in your version of firmware. Since you're running a BU-353 you could have all kinds of broken things in your firmware (not impressed by Globalsat). > But I still have a couple of them collecting data. As an aside, how and what are you collecting? I'm starting to think about setting up different loggers to catch the leap second... > They seem to get confused by leap seconds. At least that's the only thing I > can think of that changed recently. Here is a graph: > http://www.megapathdsl.net/~hmurray/ntp/leap-gps3.gif > > It started, midnight, July 31. Does anybody know when the leap second > announcement hit the satellites? first notice of this in the archives is on the 28th... so probably 0000h UTC on the 29th. > I assume it's a software bug. Looks like it repeats on a weekly pattern. > > The red line on the top is a sane unit used as a reference to show that the > time on the local system time isn't bouncing around. I've used the LVC w/ PPS as the reference clock... not sure that I trust the delay/jitter characteristics of USB enough to give me better time than a wrist-watch. > Here is a longer time span that shows a hanging bridge type pattern on the > offset: > http://www.megapathdsl.net/~hmurray/ntp/leap-gps2.gif > If you were (un)lucky, you could get fooled into thinking that the offset was > reasonably stable. > > This graph includes a few more units: > http://www.megapathdsl.net/~hmurray/ntp/leap-gps.gif > The spikes on the blue Garmin GPS 18 LVC usually happen when it is recovering > from not-enough satellites. (I haven't checked these particular samples. > That's what I found the last time I investigated.) it's "nice" to see all 3 SiRF receivers failing in the same way. that does make me think it's firmware rather than busted hardware. -- GDB has a 'break' feature; why doesn't it have 'fix' too? From bg at lysator.liu.se Tue Aug 12 16:08:28 2008 From: bg at lysator.liu.se (=?ISO-8859-1?Q?Bj=F6rn?= Gabrielsson) Date: Tue, 12 Aug 2008 22:08:28 +0200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <489F6169.30301@philpem.me.uk> References: <489F6169.30301@philpem.me.uk> Message-ID: <1218571709.2113.5.camel@bg-desktop> Hi Philip, On Sun, 2008-08-10 at 22:45 +0100, Philip Pemberton wrote: > As far as temperature regulation goes, I'm going to use a PIC > microcontroller (one of the 8-pin chips with an A/D converter) to monitor the > temperature of the crystal, and use a PID loop to control the two power > transistors to maintain a temperature of 50C +/- 2 Celsius (the accuracy spec > of the temperature sensor). I also have other higher-accuracy sensors (Dallas > DS18S20 and DS18B20) that I can calibrate with; these are accurate to around > half a degree Celsius with a resolution of 0.5C. Here is an example of a kind of synthetic TCXO using Dallas temp sensors. http://www.ijs.si/time/temp-compensation/ The resolution of the DS18x20-sensors are better than 0.5C. -- Bj?rn From dforbes at dakotacom.net Tue Aug 12 16:22:52 2008 From: dforbes at dakotacom.net (David Forbes) Date: Tue, 12 Aug 2008 13:22:52 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: <20080812183658.C1D36BCCB@ip-64-139-1-69.sjc.megapath.net> References: <20080812183658.C1D36BCCB@ip-64-139-1-69.sjc.megapath.net> Message-ID: <48A1F11C.5030108@dakotacom.net> Hal Murray wrote: > I've got a couple of GPS units that use the SiRF chips feeding NTP. I was > looking for low cost units for time keeping. They don't work very well. The > time offset of the NMEA message wanders/jitters by about 100 ms. I can > easily correct for a constant offset, but I can't dance around an offset that > won't hold still. (Oh, well. I tried.) > I looked into using some US GlobalSat units for my scope clock instead of the higher-priced GPS 18 LVC. The one I tried has an RS-232 serial port. The manual refers obliquely to a 1PPS capability, but unfortunately they didn't pin out the 1PPS signal to the board connector. I guess that their market is automotive navigation or logging, so they didn't consider it worth their while to add the 1PPS signal. I got the impression that the extra $50 you pay for the Garmin receiver is money well spent on a well-engineered device. From chris.kuethe at gmail.com Tue Aug 12 16:43:17 2008 From: chris.kuethe at gmail.com (Chris Kuethe) Date: Tue, 12 Aug 2008 13:43:17 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: <48A1F11C.5030108@dakotacom.net> References: <20080812183658.C1D36BCCB@ip-64-139-1-69.sjc.megapath.net> <48A1F11C.5030108@dakotacom.net> Message-ID: <91981b3e0808121343v257442d5r33a5117efcbcee16@mail.gmail.com> On Tue, Aug 12, 2008 at 1:22 PM, David Forbes wrote: > I looked into using some US GlobalSat units for my scope clock instead of the > higher-priced GPS 18 LVC. The one I tried has an RS-232 serial port. The manual > refers obliquely to a 1PPS capability, but unfortunately they didn't pin out the > 1PPS signal to the board connector. I guess that their market is automotive > navigation or logging, so they didn't consider it worth their while to add the > 1PPS signal. i've noticed that quite a number of globalsat modules at least hook up the 1PPS output from the chip to a test point - TP10. If you don't mind soldering, you could probably tap that output yourself.... not that you should have to. > I got the impression that the extra $50 you pay for the Garmin receiver is money > well spent on a well-engineered device. or a ublox, or a trimble, or... always check the datasheet -- GDB has a 'break' feature; why doesn't it have 'fix' too? From pico.2008 at sbcglobal.net Tue Aug 12 17:27:06 2008 From: pico.2008 at sbcglobal.net (Peter Putnam) Date: Tue, 12 Aug 2008 14:27:06 -0700 Subject: [time-nuts] Crystal Drive Level Message-ID: <48A2002A.1000507@sbcglobal.net> Greetings... I have a well-specified quartz crystal: Bliley BG71A (vintage mid 70's ?) 3.000 000 MHz parallel resonant, 100 pF 80 deg C tempco of <1.5/10e7/deg C over range 79 to 81 deg C in a glass enclosure with 9-pin miniature tube base that I would like to utilize in an oscillator circuit such as the one proposed by Bruce Griffith in his note to this list on 8/11/2008. How can I determine the crystal drive level and be certain that the drive level specified as "10 microwatts into10 ohms" will not be exceeded? Regards, Peter From bruce.griffiths at xtra.co.nz Tue Aug 12 18:37:46 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 13 Aug 2008 10:37:46 +1200 Subject: [time-nuts] Crystal Drive Level In-Reply-To: <48A2002A.1000507@sbcglobal.net> References: <48A2002A.1000507@sbcglobal.net> Message-ID: <48A210BA.4040107@xtra.co.nz> Peter Putnam wrote: > Greetings... > > I have a well-specified quartz crystal: > > Bliley BG71A > (vintage mid 70's ?) > 3.000 000 MHz > parallel resonant, 100 pF > 80 deg C > tempco of <1.5/10e7/deg C over range 79 to 81 deg C > in a glass enclosure with 9-pin miniature tube base > > that I would like to utilize in an oscillator circuit such as the one > proposed by Bruce Griffith in his note to this list on 8/11/2008. > > How can I determine the crystal drive level and be certain that the > drive level specified as "10 microwatts into10 ohms" will not be exceeded? > > Regards, > Peter > Peter 10 microwatts in 10 ohms corresponds to a crystal current of 1 mA. The question is is this an absolute limit or a recommended drive level? If it is a maximum then you should operate with a crystal current somewhat below this. Thus all you have to do is ensure that the crystal current is 1mA or less. It would be helpful to know the crystal ESR and if it is a fundamental or an overtone crystal. If its an AT cut fundamental crystal the ESR may be as high as 40 ohms or more. In which case the first stage of the oscillator buffer can be simplified to a common base stage. An AGC loop sensing the crystal current and comparing it with a reference voltage can easily be added. Another CB stage could be driven by the other end of T101's secondary and a 1K impedance load used at its collector output. An emitter follower could then be used to drive an RF detector for the AGC loop. Alternatively one could use a configuration with a high input impedance buffer as in Wenzel's circuit and drive the AGC (or monitor the level) from the buffer output. Its not too difficult to arrange for such a buffer to drive a cascade of common base stages to achieve a very high reverse isolation with relatively low distortion. However a few RF transformers are required. Using a buffer amplifier transistor with a resistive collector load is a bad idea (unless the resistor is shunted by an inductor or the primary of a transformer) as it significantly increases the phase noise of the amplifier over that which is possible with an optimised buffer amplifier design. I'll post another version of the crystal oscillator circuit in a day or so that utilises the alternative high impedance buffer circuit driving a CB cascade. It will also include AGC. Another possibility is to use the Driscoll two stage oscillator where the crystal current is limited by setting the collector current of the second stage. The second stage is driven into cutoff limiting the RF collector current of the first stage which is equal to the crystal current. However this circuit will significantly degrade the crystal Q unless the crystal ESR is relatively high (~40 ohms or more). Variants of this circuit which use AGC instead of cutoff to limit the crystal current are also possible. Another technique is to use diodes to clamp the oscillator output stage collector RF voltage peaks thus limiting the crystal current. For some variants of such Driscoll oscillators see: http://www.ko4bb.com/~bruce/XTALOSC.html NB using a LED in an oven may be somewhat problematic, so a different low noise method of biasing the various transistors may be required. Bruce From peterawson at earthlink.net Tue Aug 12 18:44:05 2008 From: peterawson at earthlink.net (Pete) Date: Tue, 12 Aug 2008 16:44:05 -0600 Subject: [time-nuts] Crystal Drive Level References: <48A2002A.1000507@sbcglobal.net> Message-ID: <001601c8fccc$f10454e0$0200a8c0@BASE1> Peter, Bruce's text explains that R103 sets the crystal current to about 1.8mA. This setting would result in operating a 10 ohm crystal at about 32uW. You would have to adjust R103 to yield about 1mA through your 10 ohm crystal. Pete Rawson From bruce.griffiths at xtra.co.nz Tue Aug 12 18:53:43 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 13 Aug 2008 10:53:43 +1200 Subject: [time-nuts] Crystal Drive Level In-Reply-To: <001601c8fccc$f10454e0$0200a8c0@BASE1> References: <48A2002A.1000507@sbcglobal.net> <001601c8fccc$f10454e0$0200a8c0@BASE1> Message-ID: <48A21477.6090802@xtra.co.nz> Pete wrote: > Peter, > > Bruce's text explains that R103 sets the crystal current to > about 1.8mA. This setting would result in operating a 10 ohm > crystal at about 32uW. You would have to adjust R103 to > yield about 1mA through your 10 ohm crystal. > > Pete Rawson > > Pete 1) The 3 MHz crystal ESR almost certainly isn't 10 ohms. The specification is actually for no more than 10 microwatts dissipated in a 10 ohm resistor connected in series with the crystal. This is a convenient way of monitoring the crystal current but the 10 ohm resistor shouldn't be permanently connected in series with the crystal as it degrades the Q. 2) The value of R103 needs to be adjusted to achieve the required output. The value required depends on the values of C101 and C102. Start with a high value for R103 (use a pot) and adjust the value until the required output is achieved. Measure the resistance of the pot and replace it with a fixed value resistor. Alternatively an AGC circuit could be used to regulate the crystal current by adjusting the base current of the oscillator transistor. Bruce From hmurray at megapathdsl.net Tue Aug 12 19:11:24 2008 From: hmurray at megapathdsl.net (Hal Murray) Date: Tue, 12 Aug 2008 16:11:24 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: Message from "Chris Kuethe" of "Tue, 12 Aug 2008 13:43:17 PDT." <91981b3e0808121343v257442d5r33a5117efcbcee16@mail.gmail.com> Message-ID: <20080812231125.4C6E7BCCB@ip-64-139-1-69.sjc.megapath.net> >> I got the impression that the extra $50 you pay for the Garmin receiver is money >> well spent on a well-engineered device. > or a ublox, or a trimble, or... always check the datasheet Does anybody have suggestions for low cost GPS units to use for timekeeping? No wiring preferred. The Garmin GPS 18 is the best candidate I know of. The LVC version includes PPS but requires minor soldering. The USB version doesn't have a PPS but it works reasonably well without any soldering. It's not supported by the officiall ntpd distributions, but I have a driver. It's not microsecond quality, but low milliseconds. The SiRF chipset is used in many low cost brands. Their latest version, III, is much more sensitive than the Garmin GPS 18. Most units I've seen are USB. Unfortunately, the NMEA output isn't well synchronized so it isn't very good for timekeeping. I took the cover off a BU-353. There is a PPS signal on the chip set, but no extra wire in the cable. It might be possible to free up the power return wire by using the shield. I haven't tried it. The Globalsat MR-350 is a RS-232 version with PPS. It comes with a funny connector and is slightly more expensive. It's easy to replace their connector. I haven't done detailed tests on the PPS. The NMEA signals are as crappy as all the other SiRF units. -- These are my opinions, not necessarily my employer's. I hate spam. From hmurray at megapathdsl.net Tue Aug 12 19:29:05 2008 From: hmurray at megapathdsl.net (Hal Murray) Date: Tue, 12 Aug 2008 16:29:05 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: Message from "Chris Kuethe" of "Tue, 12 Aug 2008 12:03:47 PDT." <91981b3e0808121203m5a7da16y70988f4eb31a4e5d@mail.gmail.com> Message-ID: <20080812232906.F1DFFBCCB@ip-64-139-1-69.sjc.megapath.net> > Yep, that's to be expected, given the iterative solver they're using. > Try turning on the ZDA message, apparently the $ sign is aligned to > the start of the second ... if its implemented in your version of > firmware. Since you're running a BU-353 you could have all kinds of > broken things in your firmware (not impressed by Globalsat). Do you expect the ZDA message to be better synchronized than any of the others? Is the BU-353 any better or worse than any of the other units using the SiRF chips? I've tried several different brands. I can't tell them apart unless I look at the physical package. > As an aside, how and what are you collecting? I'm starting to think > about setting up different loggers to catch the leap second... I just plug them into ntpd, use the noselect option on the server line, and turn on ntpd's statistics. > I've used the LVC w/ PPS as the reference clock... not sure that I > trust the delay/jitter characteristics of USB enough to give me better > time than a wrist-watch. USB isn't fundamentally evil. It's polled, so you won't get great response to something like a PPS interrupt. But the polling is handled automagically with modern hardware so It's not much worse (maybe better) than the typically interrupt batching that RS-232 chips do. I think USB will be good enough if your target is a few milliseconds rather than a few microseconds. -- These are my opinions, not necessarily my employer's. I hate spam. From newell at cei.net Tue Aug 12 20:18:27 2008 From: newell at cei.net (Scott Newell) Date: Tue, 12 Aug 2008 19:18:27 -0500 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: <20080812232906.F1DFFBCCB@ip-64-139-1-69.sjc.megapath.net> References: <20080812232906.F1DFFBCCB@ip-64-139-1-69.sjc.megapath.net> Message-ID: <200808130018.m7D0IWSg011151@host22.the-web-host.com> At 06:29 PM 8/12/2008, Hal Murray wrote: >USB isn't fundamentally evil. It's polled, so you won't get great response >to something like a PPS interrupt. But the polling is handled automagically >with modern hardware so It's not much worse (maybe better) than the typically >interrupt batching that RS-232 chips do. I wonder if using isochronous USB transfers would result in more consistent latency. -- newell N5TNL From chris.kuethe at gmail.com Tue Aug 12 20:25:28 2008 From: chris.kuethe at gmail.com (Chris Kuethe) Date: Tue, 12 Aug 2008 17:25:28 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: <200808130018.m7D0IWSg011151@host22.the-web-host.com> References: <20080812232906.F1DFFBCCB@ip-64-139-1-69.sjc.megapath.net> <200808130018.m7D0IWSg011151@host22.the-web-host.com> Message-ID: <91981b3e0808121725x7c895c2ep5a839a9c5a997f23@mail.gmail.com> On Tue, Aug 12, 2008 at 5:18 PM, Scott Newell wrote: > At 06:29 PM 8/12/2008, Hal Murray wrote: > >>USB isn't fundamentally evil. It's polled, so you won't get great response >>to something like a PPS interrupt. But the polling is handled automagically >>with modern hardware so It's not much worse (maybe better) than the typically >>interrupt batching that RS-232 chips do. Unless you configure your RS-232 chip to not batch interrupts... > I wonder if using isochronous USB transfers would result in more > consistent latency. It'd probably suck less, but you still have a trip up and down the usb protocol stack. And I haven't seen any usb-serial converters that do control lines properly... -- GDB has a 'break' feature; why doesn't it have 'fix' too? From chris.kuethe at gmail.com Tue Aug 12 20:38:07 2008 From: chris.kuethe at gmail.com (Chris Kuethe) Date: Tue, 12 Aug 2008 17:38:07 -0700 Subject: [time-nuts] Leap Second quirk, Another hanging bridge In-Reply-To: <20080812232906.F1DFFBCCB@ip-64-139-1-69.sjc.megapath.net> References: <91981b3e0808121203m5a7da16y70988f4eb31a4e5d@mail.gmail.com> <20080812232906.F1DFFBCCB@ip-64-139-1-69.sjc.megapath.net> Message-ID: <91981b3e0808121738q2931a9fbg239774f7f466662c@mail.gmail.com> On Tue, Aug 12, 2008 at 4:29 PM, Hal Murray wrote: >> Yep, that's to be expected, given the iterative solver they're using. >> Try turning on the ZDA message, apparently the $ sign is aligned to >> the start of the second ... if its implemented in your version of >> firmware. Since you're running a BU-353 you could have all kinds of >> broken things in your firmware (not impressed by Globalsat). > > Do you expect the ZDA message to be better synchronized than any of the > others? Yes. In SiRF receivers ZDA is specifically aligned to the second. I just checked my copy of the manual I got with my BU-353, and Table 1-1 NMEA Output Messages says "ZDA PPS timing message (synchronized to PPS)." RMC is produced after the navigation solution is computed and that does not happen in constant time. I found another little gem in my old email: the XTrac (High Sensitivity) version of the software does not support PPS. XTrac is often designated by "ES" in the version string. I also found that the PPS line is just a GPIO. Perhaps in the XTrac build they cut out the GPIO control code, but left in the scheduling of ZDA... *shrug* > Is the BU-353 any better or worse than any of the other units using the SiRF > chips? I've tried several different brands. I can't tell them apart unless > I look at the physical package. The hardware is about the same, but I don't trust Globalsat to not load some customized broken firmware... >> I've used the LVC w/ PPS as the reference clock... not sure that I >> trust the delay/jitter characteristics of USB enough to give me better >> time than a wrist-watch. > > USB isn't fundamentally evil. It's polled, so you won't get great response > to something like a PPS interrupt. But the polling is handled automagically > with modern hardware so It's not much worse (maybe better) than the typically > interrupt batching that RS-232 chips do. I know it's quick enough... usb ethernet, webcams, sound devices all work. But I don't think the usb implementation in most GPS receivers was designed to support timing applications. > I think USB will be good enough if your target is a few milliseconds rather > than a few microseconds. Yes, I've found that with a BU-303 (sirf2), using just NMEA timestamps, I can sync to about 5ms. Good enough for kerberos and nfs :) CK -- GDB has a 'break' feature; why doesn't it have 'fix' too? From bruce.griffiths at xtra.co.nz Tue Aug 12 21:51:45 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 13 Aug 2008 13:51:45 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <1218571709.2113.5.camel@bg-desktop> References: <489F6169.30301@philpem.me.uk> <1218571709.2113.5.camel@bg-desktop> Message-ID: <48A23E31.2000600@xtra.co.nz> Attached schematic is for a variant of the Wenzel circuit using a JFET high input impedance buffer to drive a cascaded pair of CB stages. L104 is approximately resonant with C111 at 3MHz so that either an RF choke and series resistor or a relative;y low value resistor (10K) can be used to set the JFET gate voltage. The impedance of C104 at 3MHz is about 530 ohms so a 1mA crystal current will result in about 530 mV rms across C104. An additional inductor can be used in series with the crystal to resonate out the input capacitance of the oscillator stage if required, this will allow a greater tuning range to be achieved. Inductor L104 needs to have a reasonably high Q ( > 100 @ 3MHz) to avoid degrading the loaded Q significantly. The drain current of JFET Q103 is determined by the collector current of Q104 this minimises the effect of JFET parameter variations from part to part on its drain current. The RF voltage at the source of Q103 can be amplified (a widebandwidth opamp could be used) and used to drive a detector diode for AGC purposes. Alternatively a common base stage connected to the other end of the secondary of T101 could be used an RF current source to drive a full wave diode detector with a low load resistance. This will largely eliminate the effect of the detector diode forward voltage drops on the detected output. This detector dc load current can than be compared with a reference current and the dc collector current of Q101 adjusted to regulate the crystal current. Bruce -------------- next part -------------- A non-text attachment was scrubbed... Name: OCXO_2.gif Type: image/gif Size: 44691 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20080813/70229078/attachment-0001.gif From SAIDJACK at aol.com Tue Aug 12 23:16:48 2008 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Tue, 12 Aug 2008 23:16:48 EDT Subject: [time-nuts] Designing and building an OCXO and GPSDO Message-ID: Hi Bruce, do you have any phase noise/stability measurements for these circuits? thanks, Said In a message dated 8/12/2008 18:53:38 Pacific Daylight Time, bruce.griffiths at xtra.co.nz writes: Attached schematic is for a variant of the Wenzel circuit using a JFET high input impedance buffer to drive a cascaded pair of CB stages. L104 is approximately resonant with C111 at 3MHz so that either an RF choke and series resistor or a relative;y low value resistor (10K) can be used to set the JFET gate voltage. The impedance of C104 at 3MHz is about 530 ohms so a 1mA crystal current will result in about 530 mV rms across C104. An additional inductor can be used in series with the crystal to resonate out the input capacitance of the oscillator stage if required, this will allow a greater tuning range to be achieved. Inductor L104 needs to have a reasonably high Q ( > 100 @ 3MHz) to avoid degrading the loaded Q significantly. The drain current of JFET Q103 is determined by the collector current of Q104 this minimises the effect of JFET parameter variations from part to part on its drain current. The RF voltage at the source of Q103 can be amplified (a widebandwidth opamp could be used) and used to drive a detector diode for AGC purposes. Alternatively a common base stage connected to the other end of the secondary of T101 could be used an RF current source to drive a full wave diode detector with a low load resistance. This will largely eliminate the effect of the detector diode forward voltage drops on the detected output. This detector dc load current can than be compared with a reference current and the dc collector current of Q101 adjusted to regulate the crystal current. 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. **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 ) -------------- next part -------------- Hi Bruce, do you have any phase noise/stability measurements for these circuits? thanks, Said In a message dated 8/12/2008 18:53:38 Pacific Daylight Time, bruce.griffiths at xtra.co.nz writes: Attached schematic is for a variant of the Wenzel circuit using a JFET high input impedance buffer to drive a cascaded pair of CB stages. L104 is approximately resonant with C111 at 3MHz so that either an RF choke and series resistor or a relative;y low value resistor (10K) can be used to set the JFET gate voltage. The impedance of C104 at 3MHz is about 530 ohms so a 1mA crystal current will result in about 530 mV rms across C104. An additional inductor can be used in series with the crystal to resonate out the input capacitance of the oscillator stage if required, this will allow a greater tuning range to be achieved. Inductor L104 needs to have a reasonably high Q ( > 100 @ 3MHz) to avoid degrading the loaded Q significantly. The drain current of JFET Q103 is determined by the collector current of Q104 this minimises the effect of JFET parameter variations from part to part on its drain current. The RF voltage at the source of Q103 can be amplified (a widebandwidth opamp could be used) and used to drive a detector diode for AGC purposes. Alternatively a common base stage connected to the other end of the secondary of T101 could be used an RF current source to drive a full wave diode detector with a low load resistance. This will largely eliminate the effect of the detector diode forward voltage drops on the detected output. This detector dc load current can than be compared with a reference current and the dc collector current of Q101 adjusted to regulate the crystal current. Bruce [cid:X.MA1.1218597403 at aol.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. __________________________________________________________________ Looking for a car that's sporty, fun and fits in your budget? [1]Read reviews on AOL Autos. References 1. http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/gif Size: 44691 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20080812/b7cff4c1/attachment-0001.gif From bruce.griffiths at xtra.co.nz Wed Aug 13 00:01:42 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 13 Aug 2008 16:01:42 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: <48A25CA6.3040609@xtra.co.nz> SAIDJACK at aol.com wrote: > Hi Bruce, > > > > do you have any phase noise/stability measurements for these circuits? > > > > thanks, > Said > No, I have no way of measuring phase noise at present. Nor can I yet measure ADEV with adequate sensitivity and stability. However the phase noise floor can be estimated to within a few dB. Its even possible with some effort to estimate the phase noise of the buffer amplifiers in the flicker region. If low phase noise buffer designs are used the phase noise floor depends (for a CB input stage) on the buffer equivalent input current noise and the crystal current. With sufficient crystal current the phase noise floor can be very low (<-170dBc/Hz). A phase noise measurement system would be useful for optimising the close in phase noise. The circuits are intended to be somewhat better than a gate oscillator but without the complexity involved when AGC is used. The original request design was intended for a fundamental mode oven crystal the drift of which is unlikely to be very low. Nor will the Q of such a crystal be particularly high. With an overtone crystal a means of suppressing oscillation at unwanted overtones is required. Bruce From jim77742 at gmail.com Wed Aug 13 00:49:13 2008 From: jim77742 at gmail.com (Jim Palfreyman) Date: Wed, 13 Aug 2008 14:49:13 +1000 Subject: [time-nuts] I want a good micro-controller Message-ID: Hi Folks, Well I have a nice idea in my head for a lunar occultation timer. Basically it's a normal clock that accepts a push button click and records the UTC of the events. Multiple events can be recorded and displayed back. The time must be settable and could also accept an external 1 PPS for accurate time setting. It also needs to be portable and battery powered. When it does get 1 PPS time setting it could work out how good its oscillator is an adjust for it. etc. etc. and etc. I have lots of other ideas in my head too and it's about time I settled down and thoroughly learned a decent micro controller. I want to pick one, get the stuff I need and commit to it. I've had experience with Atmel AT90S2313 but really want something with more memory, a decent number of io pins and I'd like to avoid assembler. It needs to drive a display of some form (standard LCD is fine but other options would be good) and since nearly all my references are based on 10MHz it would be nice if it could be clocked at that speed. I used to program the Acorn Achimedes and so ARM would be nice and since I'm a 20 year experienced C programmer (not C++) then that is what I'd like to program it in. Thoughts, ideas, comments would be appreciated! Oh and cheap! :-) Regards, Jim From bruce.griffiths at xtra.co.nz Wed Aug 13 01:57:34 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Wed, 13 Aug 2008 17:57:34 +1200 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: <48A277CE.3020400@xtra.co.nz> Jim Palfreyman wrote: > Hi Folks, > > Well I have a nice idea in my head for a lunar occultation timer. Basically > it's a normal clock that accepts a push button click and records the UTC of > the events. Multiple events can be recorded and displayed back. The time > must be settable and could also accept an external 1 PPS for accurate time > setting. It also needs to be portable and battery powered. When it does get > 1 PPS time setting it could work out how good its oscillator is an adjust > for it. etc. etc. and etc. > > I have lots of other ideas in my head too and it's about time I settled down > and thoroughly learned a decent micro controller. I want to pick one, get > the stuff I need and commit to it. I've had experience with Atmel AT90S2313 > but really want something with more memory, a decent number of io pins and > I'd like to avoid assembler. > > It needs to drive a display of some form (standard LCD is fine but other > options would be good) and since nearly all my references are based on 10MHz > it would be nice if it could be clocked at that speed. I used to program the > Acorn Achimedes and so ARM would be nice and since I'm a 20 year experienced > C programmer (not C++) then that is what I'd like to program it in. > > Thoughts, ideas, comments would be appreciated! > > Oh and cheap! > > :-) > > Regards, > > Jim > Jim Is this intended for field use? If so, one has to remember that it will not always be easy or practical to set up a GPS receiver on site. Provision for using the timer as an interpolation device to interpolate between timestamps obtained before and after the event from a fixed location reliable GPS receiver would greatly enhance its usefulness. Sometimes its hard enough to setup and acquire the star or other object of interest without having to worry about a GPS receiver as well. Bruce Bruce From jim77742 at gmail.com Wed Aug 13 02:05:31 2008 From: jim77742 at gmail.com (Jim Palfreyman) Date: Wed, 13 Aug 2008 16:05:31 +1000 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A277CE.3020400@xtra.co.nz> References: <48A277CE.3020400@xtra.co.nz> Message-ID: Bruce, Yes that's exactly my plan. No GPS and designed for field use. A halfway decent crystal with interpolation from 1 PPS timestamps should provide decent results. And anything else I can dream up. Bottom line is I need to know which micro-controller to embrace. Thanks Didier for your suggestion. Any others? Jim 2008/8/13 Bruce Griffiths > Jim Palfreyman wrote: > > Hi Folks, > > > > Well I have a nice idea in my head for a lunar occultation timer. > Basically > > it's a normal clock that accepts a push button click and records the UTC > of > > the events. Multiple events can be recorded and displayed back. The time > > must be settable and could also accept an external 1 PPS for accurate > time > > setting. It also needs to be portable and battery powered. When it does > get > > 1 PPS time setting it could work out how good its oscillator is an adjust > > for it. etc. etc. and etc. > > > > I have lots of other ideas in my head too and it's about time I settled > down > > and thoroughly learned a decent micro controller. I want to pick one, get > > the stuff I need and commit to it. I've had experience with Atmel > AT90S2313 > > but really want something with more memory, a decent number of io pins > and > > I'd like to avoid assembler. > > > > It needs to drive a display of some form (standard LCD is fine but other > > options would be good) and since nearly all my references are based on > 10MHz > > it would be nice if it could be clocked at that speed. I used to program > the > > Acorn Achimedes and so ARM would be nice and since I'm a 20 year > experienced > > C programmer (not C++) then that is what I'd like to program it in. > > > > Thoughts, ideas, comments would be appreciated! > > > > Oh and cheap! > > > > :-) > > > > Regards, > > > > Jim > > > Jim > > Is this intended for field use? > If so, one has to remember that it will not always be easy or practical > to set up a GPS receiver on site. > Provision for using the timer as an interpolation device to interpolate > between timestamps obtained before and after the event from a fixed > location reliable GPS receiver would greatly enhance its usefulness. > Sometimes its hard enough to setup and acquire the star or other object > of interest without having to worry about a GPS receiver as well. > > Bruce > > > 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 jmiles at pop.net Wed Aug 13 04:23:33 2008 From: jmiles at pop.net (John Miles) Date: Wed, 13 Aug 2008 01:23:33 -0700 Subject: [time-nuts] I want a good micro-controller In-Reply-To: Message-ID: It's sort of a religious matter, but if you are looking for an easy-to-use part with great, free C/C++ support, you'd most likely be happy with the AtMEGA series. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of Jim Palfreyman > Sent: Tuesday, August 12, 2008 11:06 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] I want a good micro-controller > > > Bruce, > > Yes that's exactly my plan. No GPS and designed for field use. A halfway > decent crystal with interpolation from 1 PPS timestamps should provide > decent results. And anything else I can dream up. > > Bottom line is I need to know which micro-controller to embrace. > > Thanks Didier for your suggestion. Any others? > > Jim > > From wje at quackers.net Wed Aug 13 07:00:16 2008 From: wje at quackers.net (wje) Date: Wed, 13 Aug 2008 07:00:16 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: <48A2BEC0.50004@quackers.net> My favorite for many uses is the Freescale MC68HC908QT4, or others in that series. Freescale provides a complete C development environment for free. The QT4 is an 8-pin package, with up to 6 I/O pins. I've used it for everything from a 555 timer replacement to the controller for an RPM meter, to the controller for a GPS/Rb/xtal freqency standard. Of course, for many purposes it doesn't particularly matter whose chip you use, as long as the tools are adequate. There are any number of choices, including the PIC line, which everyone but me seems to love. Bill Ezell ---------- They said 'Windows or better' so I used Linux. John Miles wrote: It's sort of a religious matter, but if you are looking for an easy-to-use part with great, free C/C++ support, you'd most likely be happy with the AtMEGA series. -- john, KE5FX -----Original Message----- From: [1]time-nuts-bounces at febo.com [[2]mailto:time-nuts-bounces at febo.com]On Behalf Of Jim Palfreyman Sent: Tuesday, August 12, 2008 11:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] I want a good micro-controller Bruce, Yes that's exactly my plan. No GPS and designed for field use. A halfway decent crystal with interpolation from 1 PPS timestamps should provide decent results. And anything else I can dream up. Bottom line is I need to know which micro-controller to embrace. Thanks Didier for your suggestion. Any others? Jim _______________________________________________ time-nuts mailing list -- [3]time-nuts at febo.com To unsubscribe, go to [4]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. References 1. mailto:time-nuts-bounces at febo.com 2. mailto:time-nuts-bounces at febo.com 3. mailto:time-nuts at febo.com 4. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts From cupido at mail.ua.pt Wed Aug 13 07:23:41 2008 From: cupido at mail.ua.pt (Luis Cupido) Date: Wed, 13 Aug 2008 12:23:41 +0100 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A2BEC0.50004@quackers.net> References: <48A2BEC0.50004@quackers.net> Message-ID: <48A2C43D.8080800@mail.ua.pt> >There are any number of >choices, including the PIC line, which everyone but me seems to love. Bill, You're not alone ;-) Luis Cupido. ct1dmk. wje wrote: > My favorite for many uses is the Freescale MC68HC908QT4, or others in > that series. Freescale provides a complete C development environment > for free. The QT4 is an 8-pin package, with up to 6 I/O pins. I've used > it for everything from a 555 timer replacement to the controller for an > RPM meter, to the controller for a GPS/Rb/xtal freqency standard. Of > course, for many purposes it doesn't particularly matter whose chip you > use, as long as the tools are adequate. There are any number of > choices, including the PIC line, which everyone but me seems to love. > Bill Ezell > ---------- > They said 'Windows or better' > so I used Linux. > > John Miles wrote: > > It's sort of a religious matter, but if you are looking for an easy-to-use > part with great, free C/C++ support, you'd most likely be happy with the > AtMEGA series. > > -- john, KE5FX > > > > -----Original Message----- > From: [1]time-nuts-bounces at febo.com [[2]mailto:time-nuts-bounces at febo.com]On > Behalf Of Jim Palfreyman > Sent: Tuesday, August 12, 2008 11:06 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] I want a good micro-controller > > > Bruce, > > Yes that's exactly my plan. No GPS and designed for field use. A halfway > decent crystal with interpolation from 1 PPS timestamps should provide > decent results. And anything else I can dream up. > > Bottom line is I need to know which micro-controller to embrace. > > Thanks Didier for your suggestion. Any others? > > Jim > > > > > _______________________________________________ > time-nuts mailing list -- [3]time-nuts at febo.com > To unsubscribe, go to [4]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > References > > 1. mailto:time-nuts-bounces at febo.com > 2. mailto:time-nuts-bounces at febo.com > 3. mailto:time-nuts at febo.com > 4. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > _______________________________________________ > time-nuts mailing list -- 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 jherrero at hvsistemas.es Wed Aug 13 08:52:52 2008 From: jherrero at hvsistemas.es (Javier Herrero) Date: Wed, 13 Aug 2008 14:52:52 +0200 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A2C43D.8080800@mail.ua.pt> References: <48A2BEC0.50004@quackers.net> <48A2C43D.8080800@mail.ua.pt> Message-ID: <48A2D924.3040809@hvsistemas.es> Luis Cupido escribi?: > >There are any number of > >choices, including the PIC line, which everyone but me seems to love. > > Bill, > You're not alone ;-) > > Luis Cupido. > ct1dmk. > I'm with both of yours... This is a recurrent discussion here, and there are some deep PIC lovers... but once I've used an ATtiny... I would never use a PIC again for a new design. And for those larger needs, any ARM7 outperforms the best PIC in price and performance :) 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 holrum at hotmail.com Wed Aug 13 10:19:45 2008 From: holrum at hotmail.com (Mark Sims) Date: Wed, 13 Aug 2008 14:19:45 +0000 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: Well, I'm particularly fond of the MegaDonkey from mega-donkey.com It does everything I want a microcontroller to do (it should, I designed it). Atmel ATMEGA2561, 256K flash, 8K RAM, LCD 160x80 graphics touchscreen display, two serial ports, IIC ports, A/D ports, lots of I/O pins, beeper, prototyping area, wonderful open-source software, makes Julianne fries, gives a fair backrub. The softwware is in avr-gcc so you have a full blown C compiler. There is also a version with a Mega128 chip (128K flash,4K RAM, 128x64 LCD, mediocre backrubs) and one without the LCD. The software has a software time-of-day clock with crystal freq calibration capability. Has demo routines for digital and analog clock displays. Internally it runs off a 10 KHz interrupt so you can get that level of resolution. You could add a battery backed IIC clock chip (we have a couple of circuit boards floating around, haven't written the software yet). Also there is a 8 pin SOIC chip pad area in the prototyping area where a clock chip could be added). ---------------------------------------- _________________________________________________________________ Reveal your inner athlete and share it with friends on Windows Live. http://revealyourinnerathlete.windowslive.com?locale=en-us&ocid=TXT_TAGLM_WLYIA_whichathlete_us From jra at febo.com Wed Aug 13 10:27:28 2008 From: jra at febo.com (John Ackermann N8UR) Date: Wed, 13 Aug 2008 10:27:28 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: <48A2EF50.8050205@febo.com> Mark Sims wrote: > Well, I'm particularly fond of the MegaDonkey from mega-donkey.com It does everything I want a microcontroller to do (it should, I designed it). Atmel ATMEGA2561, 256K flash, 8K RAM, LCD 160x80 graphics touchscreen display, two serial ports, IIC ports, A/D ports, lots of I/O pins, beeper, prototyping area, wonderful open-source software, makes Julianne fries, gives a fair backrub. The softwware is in avr-gcc so you have a full blown C compiler. There is also a version with a Mega128 chip (128K flash,4K RAM, 128x64 LCD, mediocre backrubs) and one without the LCD. > > The software has a software time-of-day clock with crystal freq calibration capability. Has demo routines for digital and analog clock displays. Internally it runs off a 10 KHz interrupt so you can get that level of resolution. You could add a battery backed IIC clock chip (we have a couple of circuit boards floating around, haven't written the software yet). Also there is a 8 pin SOIC chip pad area in the prototyping area where a clock chip could be added). Mark, sounds very cool but www.mega-donkey.com or mega-donkey.com don't resolve... John From peterawson at earthlink.net Wed Aug 13 11:33:03 2008 From: peterawson at earthlink.net (Pete) Date: Wed, 13 Aug 2008 09:33:03 -0600 Subject: [time-nuts] I want a good micro-controller References: <48A2EF50.8050205@febo.com> Message-ID: <002301c8fd59$e2bea240$0200a8c0@BASE1> The URL works fine from here. Pete From SAIDJACK at aol.com Wed Aug 13 12:24:46 2008 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Wed, 13 Aug 2008 12:24:46 EDT Subject: [time-nuts] Designing and building an OCXO and GPSDO Message-ID: Thanks Bruce, it would be interesting to see how the different topologies affect phase noise and stability etc, and what kind of performance can be achieved. bye, Said In a message dated 8/12/2008 20:19:03 Pacific Daylight Time, SAIDJACK@ aol.com writes: Hi Bruce, do you have any phase noise/stability measurements for these circuits? thanks, Said In a message dated 8/12/2008 18:53:38 Pacific Daylight Time, bruce.griffiths at xtra.co.nz writes: Attached schematic is for a variant of the Wenzel circuit using a JFET high input impedance buffer to drive a cascaded pair of CB stages. L104 is approximately resonant with C111 at 3MHz so that either an RF choke and series resistor or a relative;y low value resistor (10K) can be used to set the JFET gate voltage. The impedance of C104 at 3MHz is about 530 ohms so a 1mA crystal current will result in about 530 mV rms across C104. An additional inductor can be used in series with the crystal to resonate out the input capacitance of the oscillator stage if required, this will allow a greater tuning range to be achieved. Inductor L104 needs to have a reasonably high Q ( > 100 @ 3MHz) to avoid degrading the loaded Q significantly. The drain current of JFET Q103 is determined by the collector current of Q104 this minimises the effect of JFET parameter variations from part to part on its drain current. The RF voltage at the source of Q103 can be amplified (a widebandwidth opamp could be used) and used to drive a detector diode for AGC purposes. Alternatively a common base stage connected to the other end of the secondary of T101 could be used an RF current source to drive a full wave diode detector with a low load resistance. This will largely eliminate the effect of the detector diode forward voltage drops on the detected output. This detector dc load current can than be compared with a reference current and the dc collector current of Q101 adjusted to regulate the crystal current. 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. **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut0005000000001 7 ) Hi Bruce, do you have any phase noise/stability measurements for these circuits? thanks, Said In a message dated 8/12/2008 18:53:38 Pacific Daylight Time, bruce.griffiths at xtra.co.nz writes: Attached schematic is for a variant of the Wenzel circuit using a JFET high input impedance buffer to drive a cascaded pair of CB stages. L104 is approximately resonant with C111 at 3MHz so that either an RF choke and series resistor or a relative;y low value resistor (10K) can be used to set the JFET gate voltage. The impedance of C104 at 3MHz is about 530 ohms so a 1mA crystal current will result in about 530 mV rms across C104. An additional inductor can be used in series with the crystal to resonate out the input capacitance of the oscillator stage if required, this will allow a greater tuning range to be achieved. Inductor L104 needs to have a reasonably high Q ( > 100 @ 3MHz) to avoid degrading the loaded Q significantly. The drain current of JFET Q103 is determined by the collector current of Q104 this minimises the effect of JFET parameter variations from part to part on its drain current. The RF voltage at the source of Q103 can be amplified (a widebandwidth opamp could be used) and used to drive a detector diode for AGC purposes. Alternatively a common base stage connected to the other end of the secondary of T101 could be used an RF current source to drive a full wave diode detector with a low load resistance. This will largely eliminate the effect of the detector diode forward voltage drops on the detected output. This detector dc load current can than be compared with a reference current and the dc collector current of Q101 adjusted to regulate the crystal current. Bruce [cid:X.MA1.1218597403 at aol.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. __________________________________________________________________ Looking for a car that's sporty, fun and fits in your budget? [1]Read reviews on AOL Autos. References 1. http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 _______________________________________________ time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 ) -------------- next part -------------- Thanks Bruce, it would be interesting to see how the different topologies affect phase noise and stability etc, and what kind of performance can be achieved. bye, Said In a message dated 8/12/2008 20:19:03 Pacific Daylight Time, SAIDJACK at aol.com writes: Hi Bruce, do you have any phase noise/stability measurements for these circuits? thanks, Said In a message dated 8/12/2008 18:53:38 Pacific Daylight Time, bruce.griffiths at xtra.co.nz writes: Attached schematic is for a variant of the Wenzel circuit using a JFET high input impedance buffer to drive a cascaded pair of CB stages. L104 is approximately resonant with C111 at 3MHz so that either an RF choke and series resistor or a relative;y low value resistor (10K) can be used to set the JFET gate voltage. The impedance of C104 at 3MHz is about 530 ohms so a 1mA crystal current will result in about 530 mV rms across C104. An additional inductor can be used in series with the crystal to resonate out the input capacitance of the oscillator stage if required, this will allow a greater tuning range to be achieved. Inductor L104 needs to have a reasonably high Q ( > 100 @ 3MHz) to avoid degrading the loaded Q significantly. The drain current of JFET Q103 is determined by the collector current of Q104 this minimises the effect of JFET parameter variations from part to part on its drain current. The RF voltage at the source of Q103 can be amplified (a widebandwidth opamp could be used) and used to drive a detector diode for AGC purposes. Alternatively a common base stage connected to the other end of the secondary of T101 could be used an RF current source to drive a full wave diode detector with a low load resistance. This will largely eliminate the effect of the detector diode forward voltage drops on the detected output. This detector dc load current can than be compared with a reference current and the dc collector current of Q101 adjusted to regulate the crystal current. 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. **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut000 50000000017 ) Hi Bruce, do you have any phase noise/stability measurements for these circuits? thanks, Said In a message dated 8/12/2008 18:53:38 Pacific Daylight Time, bruce.griffiths at xtra.co.nz writes: Attached schematic is for a variant of the Wenzel circuit using a JFET high input impedance buffer to drive a cascaded pair of CB stages. L104 is approximately resonant with C111 at 3MHz so that either an RF choke and series resistor or a relative;y low value resistor (10K) can be used to set the JFET gate voltage. The impedance of C104 at 3MHz is about 530 ohms so a 1mA crystal current will result in about 530 mV rms across C104. An additional inductor can be used in series with the crystal to resonate out the input capacitance of the oscillator stage if required, this will allow a greater tuning range to be achieved. Inductor L104 needs to have a reasonably high Q ( > 100 @ 3MHz) to avoid degrading the loaded Q significantly. The drain current of JFET Q103 is determined by the collector current of Q104 this minimises the effect of JFET parameter variations from part to part on its drain current. The RF voltage at the source of Q103 can be amplified (a widebandwidth opamp could be used) and used to drive a detector diode for AGC purposes. Alternatively a common base stage connected to the other end of the secondary of T101 could be used an RF current source to drive a full wave diode detector with a low load resistance. This will largely eliminate the effect of the detector diode forward voltage drops on the detected output. This detector dc load current can than be compared with a reference current and the dc collector current of Q101 adjusted to regulate the crystal current. Bruce [cid:X.MA1.1218597403 at aol.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. __________________________________________________________________ Looking for a car that's sporty, fun and fits in your budget? [1]Read reviews on AOL Autos. References 1. http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut0005 0000000017 [cid:X.MA1.1218644679 at aol.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. __________________________________________________________________ Looking for a car that's sporty, fun and fits in your budget? [1]Read reviews on AOL Autos. References 1. http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/gif Size: 44691 bytes Desc: not available Url : http://www.febo.com/pipermail/time-nuts/attachments/20080813/3d96282f/attachment-0001.gif From hmurray at megapathdsl.net Wed Aug 13 13:08:47 2008 From: hmurray at megapathdsl.net (Hal Murray) Date: Wed, 13 Aug 2008 10:08:47 -0700 Subject: [time-nuts] I want a good micro-controller In-Reply-To: Message from wje of "Wed, 13 Aug 2008 07:00:16 EDT." <48A2BEC0.50004@quackers.net> Message-ID: <20080813170848.942D5BCCB@ip-64-139-1-69.sjc.megapath.net> > There are any number of choices, including the PIC line, which > everyone but me seems to love. Many years ago, Microchip was friendly to hobbyists so they collected a big fan club. -- These are my opinions, not necessarily my employer's. I hate spam. From hmurray at megapathdsl.net Wed Aug 13 14:50:53 2008 From: hmurray at megapathdsl.net (Hal Murray) Date: Wed, 13 Aug 2008 11:50:53 -0700 Subject: [time-nuts] I want a good micro-controller In-Reply-To: Message from "Jim Palfreyman" of "Wed, 13 Aug 2008 14:49:13 +1000." Message-ID: <20080813185054.3A974BCCB@ip-64-139-1-69.sjc.megapath.net> > It needs to drive a display of some form (standard LCD is fine but > other options would be good) and since nearly all my references are > based on 10MHz it would be nice if it could be clocked at that speed. > I used to program the Acorn Achimedes and so ARM would be nice and > since I'm a 20 year experienced C programmer (not C++) then that is > what I'd like to program it in. > Thoughts, ideas, comments would be appreciated! Are you looking for a chip to use in a board you are going to design, or an existing board that will do your job, possibly with some hacking? I'm not up to date on boards. The mega-donkey looks like a good straw man. (I think you need something else to program it.) Vendors often have inexpensive low end development kits. (Some of the high end boards are quite pricey for a hobby project.) Here is a sample: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=ATAVRDB101- ND (It needs a programmer too.) Have you considered using a laptop? Older (real old?) ones had printer ports so you could get a PPS in. Assuming you are looking for a chip: I know of 3 families of 8 bit chips: AVR from Atmel, PIC from Microchip, and 8051s from several vendors. It's a cut-throat market area. I think they all make chips that are roughly equivalent. If you need something more powerful, the ARM chips are probably the way to go. I like the Atmel chips, both ARM and AVR. Their I/O units are generally not too quirky and the documentation is pretty good. Digikey carries them. They usually have a one page sheet that compares all of their chips. Here is a sample, but it doesn't show the I/O stuff. http://www.atmel.com/products/AVR/default_picopower.asp > Oh and cheap! I don't think the price of the CPU chip will be a big deal for a low volume project. Things get interesting if you want to buy a million of them. Often, a vendor will make several versions of a chip with the same I/O but different sizes of RAM/Flash. For a hobby project, I'd get the biggest one, just in case. Odds and ends: If you have a PPS, you probably have 10 MHz too. If you can use that for your CPU clock, then you don't have to worry about calibration. Running off batteries won't be a problem. All your power will go into the backlight for the LCD. :) -- These are my opinions, not necessarily my employer's. I hate spam. From holrum at hotmail.com Wed Aug 13 16:04:21 2008 From: holrum at hotmail.com (Mark Sims) Date: Wed, 13 Aug 2008 20:04:21 +0000 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: Hello Hal, The MegaDonkey can be programmed in one of three ways: 1) the on board bootloader via either of the onboard RS-232 ports (or use a USB-RS232 dongle). The bootloader is VERY fast (over 10Kb/sec... about as fast as the chip can write it's flash memory). One neat feature of the system is the ability to echo all the screen drawing commands/touchscreen to a host PC. You can remotely control the unit via a wireless dongle or not use an on-board LCD screen. The serial ports match standard PC ports. You use a null modem cable to connect it to a PC. 2) via the Atmel standard ISP (10 pin) connector. Any standard ATMEL programmer can be used. 3) via the Atmel standard JTAG port. You can use the ATMEL JTAG-ICE device for programming and debugging (but it is always best not to put bugs in your program to start with ;-) ) Although Atmel's programmers and JTAG ICE are nice, I MUCH prefer the bootloader approach. Atmel's programmers can be a bit cumbersome and finicky about establishing connections to their processors. If you are developing commercial applications we have a high-grade crypto bootloader available (DES, 3DES, AES256, XTEA). The software is all written in C. We deliberately try to use as little of the language as possible... makes it easier for non-gurus to understand. We used the avg-gcc compiler in the popular free, open source WIN-AVR package. This compiler integrates very well with Atmel's free AVR Studio development environment (if you like developing in an IDE environment). ---------------------------------------- >I'm not up to date on boards. The mega-donkey looks like a good straw man. >(I think you need something else to program it.) ---------------------------------------- _________________________________________________________________ Get Windows Live and get whatever you need, wherever you are. Start here. http://www.windowslive.com/default.html?ocid=TXT_TAGLM_WL_Home_082008 From newell at cei.net Wed Aug 13 16:10:50 2008 From: newell at cei.net (Scott Newell) Date: Wed, 13 Aug 2008 15:10:50 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: <200808132011.m7DKB3RE000814@mail960c35.nsolutionszone.com> At 03:04 PM 8/13/2008 , Mark Sims wrote: >approach. Atmel's programmers can be a bit cumbersome and finicky about establishing connections to their processors. No kidding! I'm hacking on the new HP 20B financial calculator (think of it as a $40 AT91SAM7L128 demo board), and that SAMBA program takes 15 minutes (!) to dump or program 128k flash through the serial port. When it decides to connect, that is. My hacked up OpenOCD script does it in less than 30s through JTAG. -- newell N5TNL From bruce.griffiths at xtra.co.nz Wed Aug 13 18:13:32 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 14 Aug 2008 10:13:32 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: <48A35C8C.3020201@xtra.co.nz> SAIDJACK at aol.com wrote: > Thanks Bruce, > > > > it would be interesting to see how the different topologies affect > phase noise and stability etc, and what kind of performance can be > achieved. > > > > bye, > > Said > Said When the output signal is filtered by the crystal, the phase noise floor is independent of the particular oscillator design. The phase noise floor only depends on the phase noise of the buffer amplifier. Techniques for designing low phase noise buffer amplifiers are well established. Basically the idea is to keep the dc and low frequency noise at the buffer amplifier output low and use RF negative feedback to stabilise the buffer amplifier gain (reduces flicker phase noise). Thus low power supply noise is required (it modulates amplifier phase shift and thus contributes to phase noise). For offsets within the crystal bandwidth, intrinsic crystal flicker noise contributes to the phase noise as does the phase noise of the oscillator active components. The oscillator can be run in class A if AGC is used, RF negative feedback can then be used to reduce the sustaining circuit phase noise. A Colpitts crystal oscillator typically operates in Class C with a small duty cycle, the transistor should never saturate. Thus with carefully optimised buffer amplifiers and a fixed crystal current and the same crystal, the various circuits should only differ substantially in their flicker phase noise characteristics. In a well designed circuit the stability will be largely determined by component quality, amplitude stability and residual temperature fluctuations. Without some stabilising RF negative feedback the flicker phase noise will be relatively high, however the transistor is on for part of the cycle which tends to reduce the phase noise. Using a 100k resistor from the FET gate to ground isnt exactly conducive to a low phase noise floor unless the amplitude of the signal at the gate is large. It would certainly be useful to evaluate the phase noise of the various oscillator circuits particularly in the flicker phase noise region as well as ADEV as a function of time. Bruce From bruce.griffiths at xtra.co.nz Wed Aug 13 19:01:23 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 14 Aug 2008 11:01:23 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: <48A367C3.3010405@xtra.co.nz> SAIDJACK at aol.com wrote: > Thanks Bruce, > > > > it would be interesting to see how the different topologies affect > phase noise and stability etc, and what kind of performance can be > achieved. > > > > bye, > > Said > > > Said One way to evaluate the merits of various oscillator circuits would be to build an example of each and then measure their phase noise and ADEV. To keep the number of variables and costs down all oscillators should use the same 10MHz fundamental crystal. The oscillators should not be enclosed in their own oven, however an enclosure with a long thermal time constant can be used. The oscillator output should be +7dBm into 50 ohms. No EFC and probably no trimmer cap (however this requires that a TSC5120A or similar be used to measure the ADEVand phase noise). Power supply should be standardised at +12V. Bruce From cupido at mail.ua.pt Wed Aug 13 19:22:54 2008 From: cupido at mail.ua.pt (Luis Cupido) Date: Thu, 14 Aug 2008 00:22:54 +0100 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <200808132011.m7DKB3RE000814@mail960c35.nsolutionszone.com> References: <200808132011.m7DKB3RE000814@mail960c35.nsolutionszone.com> Message-ID: <48A36CCE.9070203@mail.ua.pt> Another view ! I found myself going in another direction recently... PC104 :-) ... Designing a board for a really small think, one's favorite either PIC 51's ATmel freescale or whatever seems to be fine. A small demo board or existing PCB from some vendors seems fine to me also. but when it comes to a medium to high power thing lets say in the ARM category and above, it becomes a lot easier to use a PC104 board. Specially because those pop-up on ebay at less than most of the kits and demo boards for uC that have 1/100 of the processing power. Not to mention the tools available that are the same as any for the PC architecture... Compilers assemblers etc... sky is the limit. ROM can be a compactFlash-ide disk, a few bucks you get 1Gb if you want, plus Ethernet, LCD/VGA USB LPT, 2xRS232 etc (depending on the specific model). For more complex things it just doesn't pay to make a specific PCB (unless for big qty business production)... Last year I got on ebay a few 233MHz Pentium PC104 with eth10/100 + 2xRS232 + lpt + 2xusb + Kb for 30euro each!!! What else could we do with that money ?! ;-) Ok fine they eat 5V at 800mA... not exactely low power... but there are better ones... my 2 cents ;-) Luis Cupido. ct1dmk. From SAIDJACK at aol.com Wed Aug 13 19:39:47 2008 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Wed, 13 Aug 2008 19:39:47 EDT Subject: [time-nuts] Designing and building an OCXO and GPSDO Message-ID: Yup, I agree. I wish I did have one of those TSC5120A's! Or "at least" an E5052A/B. bye, Said In a message dated 8/13/2008 16:03:00 Pacific Daylight Time, bruce.griffiths at xtra.co.nz writes: SAIDJACK at aol.com wrote: > Thanks Bruce, > > > > it would be interesting to see how the different topologies affect > phase noise and stability etc, and what kind of performance can be > achieved. > > > > bye, > > Said > > > Said One way to evaluate the merits of various oscillator circuits would be to build an example of each and then measure their phase noise and ADEV. To keep the number of variables and costs down all oscillators should use the same 10MHz fundamental crystal. The oscillators should not be enclosed in their own oven, however an enclosure with a long thermal time constant can be used. The oscillator output should be +7dBm into 50 ohms. No EFC and probably no trimmer cap (however this requires that a TSC5120A or similar be used to measure the ADEVand phase noise). Power supply should be standardised at +12V. 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. **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 ) From bruce.griffiths at xtra.co.nz Wed Aug 13 19:54:28 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 14 Aug 2008 11:54:28 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: <48A37434.10702@xtra.co.nz> SAIDJACK at aol.com wrote: > Yup, I agree. > > I wish I did have one of those TSC5120A's! > > Or "at least" an E5052A/B. > > bye, > Said > > > Said Maybe a "competition" between various designs is in order? Restricting the designs to those reputed to have low phase noise and/or high stability is perhaps in order. We don't want endless slight variations on the same theme, significant design variations only would be useful in evaluating relative performance. Examples using general purpose and high ft transistors as well as modular amplifiers (perhaps only useful for 80MHz and above)? Bruce From jmiles at pop.net Wed Aug 13 19:57:16 2008 From: jmiles at pop.net (John Miles) Date: Wed, 13 Aug 2008 16:57:16 -0700 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: Message-ID: If you don't want pushbutton convenience, you can measure the close-in phase noise with not much more than a $5 mixer and $2 opamp. It will take a lot of "sweat equity," and you will need to build two of whatever you're measuring, or buy/borrow a known-cleaner source at the same frequency. TSC analyzers are great but they are not the only way to go. Actually their biggest advantages lie in their size/weight and the fact that the reference doesn't have to be at the same frequency as the DUT. Other than that, their performance is not necessarily better than a homebrew single-mixer quadrature PLL or an 11848A. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of SAIDJACK at aol.com > Sent: Wednesday, August 13, 2008 4:40 PM > To: time-nuts at febo.com > Subject: Re: [time-nuts] Designing and building an OCXO and GPSDO > > > Yup, I agree. > > I wish I did have one of those TSC5120A's! > > Or "at least" an E5052A/B. > > bye, > Said > > > In a message dated 8/13/2008 16:03:00 Pacific Daylight Time, > bruce.griffiths at xtra.co.nz writes: > > SAIDJACK at aol.com wrote: > > Thanks Bruce, > > > > > > > > it would be interesting to see how the different topologies affect > > phase noise and stability etc, and what kind of performance can be > > achieved. > > > > > > > > bye, > > > > Said > > > > > > > Said > > One way to evaluate the merits of various oscillator circuits would be > to build an example of each and then measure their phase noise and ADEV. > > To keep the number of variables and costs down all oscillators should > use the same 10MHz fundamental crystal. > The oscillators should not be enclosed in their own oven, however an > enclosure with a long thermal time constant can be used. > The oscillator output should be +7dBm into 50 ohms. > No EFC and probably no trimmer cap (however this requires that a > TSC5120A or similar be used to measure the ADEVand phase noise). > Power supply should be standardised at +12V. > > > 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. **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000 017 ) _______________________________________________ time-nuts mailing list -- 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.paddock at gmail.com Wed Aug 13 20:06:47 2008 From: bob.paddock at gmail.com (Bob Paddock) Date: Wed, 13 Aug 2008 20:06:47 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A2D924.3040809@hvsistemas.es> References: <48A2BEC0.50004@quackers.net> <48A2C43D.8080800@mail.ua.pt> <48A2D924.3040809@hvsistemas.es> Message-ID: > any ARM7 outperforms the best PIC in price and performance :) http://beagleboard.org/ Get them from DigiKey, $149. http://dkc1.digikey.com/us/mkt/beagleboard.html "The USB-powered Beagle Board is a low-cost, fan-less single board computer utilizing Texas Instruments' OMAP3530 [ARM] application processor that unleashes laptop-like performance and expansion without the bulk, expense, or noise of typical desktop machines. Beagle Board is based on an OMAP3530 application processor featuring an ARM(R) Cortex?-A8 running at up to 600MHz and delivering over 1,200 Dhrystone MIPS of performance via superscalar operation with highly accurate branch prediction and 256KB of L2 cache. Focal to Beagle Board experience is the high-speed USB 2.0 on-the-go (OTG) port that can be utilized to provide power to the board or to deliver highly flexible expansion. Standard PC peripherals can be connected to Beagle Board using the USB with a mini-A to standard-A cable adapter, DVI-D using an HDMI to DVI-D adapter, or through the MMC/SD/SDIO connector enabling a complete desktop experience." -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ From bruce.griffiths at xtra.co.nz Wed Aug 13 21:12:39 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 14 Aug 2008 13:12:39 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: <48A38687.9060100@xtra.co.nz> John Miles wrote: > If you don't want pushbutton convenience, you can measure the close-in phase > noise with not much more than a $5 mixer and $2 opamp. It will take a lot > of "sweat equity," and you will need to build two of whatever you're > measuring, or buy/borrow a known-cleaner source at the same frequency. > > TSC analyzers are great but they are not the only way to go. Actually their > biggest advantages lie in their size/weight and the fact that the reference > doesn't have to be at the same frequency as the DUT. Other than that, their > performance is not necessarily better than a homebrew single-mixer > quadrature PLL or an 11848A. > > -- john, KE5FX > John For compatibility with the PLL technique a trimmer and EFC is required. Using back to back varicaps is supposed to minimise the effect of varicap noise on the oscillator phase noise. The next step below using a cross correlation technique is to use a low phase noise frequency multiplier to decrease the system phase noise floor. A good multiplier can have a significantly lower phase noise floor than a mixer in the flicker phase noise region. Another candidate for evaluation would be an oscillator using a low phase noise modular amplifier with 50 ohm input and output impedance. A splitter is used on the amplifier output to extract a useful signal. Lumped component 1/4 wave lines are used on the input of the modular amplifier and the feedback output of the splitter to achieve a match to Rs/2, where Rs is the crystal series resistance. A full wave diode clamp can be incorporated to limit the crystal dissipation. A phase noise of -156dBc/Hz @100Hz offset has been achieved with such an oscillator. Bruce From cupido at mail.ua.pt Thu Aug 14 06:55:24 2008 From: cupido at mail.ua.pt (Luis Cupido) Date: Thu, 14 Aug 2008 11:55:24 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: References: Message-ID: <48A40F1C.4020800@mail.ua.pt> Related to this, I have a question in my mind for sometime. How close to a decent phase-noise setup are we if we down convert and use a low frequency spectrum analyzer ? (downconverting with the best XTAL LO we can imagine). My target is microwaves and millimeter waves so I have to down convert anyway, Or then I have to live with what my spectrum analyzer show me (a tek 492, in my case). --- Rephrasing the question, how much better are the low frequency spectrum analyzers comparing to the microwave spectrum analysers (in phase noise I mean)? Any comments ? Luis Cupido. ct1dmk. P.S.(I know that I'm limites to 100Hz RBW with my 492... and I would like also to measure closer than that ) John Miles wrote: > If you don't want pushbutton convenience, you can measure the close-in phase > noise with not much more than a $5 mixer and $2 opamp. It will take a lot > of "sweat equity," and you will need to build two of whatever you're > measuring, or buy/borrow a known-cleaner source at the same frequency. > > TSC analyzers are great but they are not the only way to go. Actually their > biggest advantages lie in their size/weight and the fact that the reference > doesn't have to be at the same frequency as the DUT. Other than that, their > performance is not necessarily better than a homebrew single-mixer > quadrature PLL or an 11848A. > > -- john, KE5FX > > >> -----Original Message----- >> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On >> Behalf Of SAIDJACK at aol.com >> Sent: Wednesday, August 13, 2008 4:40 PM >> To: time-nuts at febo.com >> Subject: Re: [time-nuts] Designing and building an OCXO and GPSDO >> >> >> Yup, I agree. >> >> I wish I did have one of those TSC5120A's! >> >> Or "at least" an E5052A/B. >> >> bye, >> Said >> From bruce.griffiths at xtra.co.nz Thu Aug 14 07:40:12 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Thu, 14 Aug 2008 23:40:12 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A40F1C.4020800@mail.ua.pt> References: <48A40F1C.4020800@mail.ua.pt> Message-ID: <48A4199C.5010109@xtra.co.nz> Luis Cupido wrote: > Related to this, I have a question in my mind for sometime. > > How close to a decent phase-noise setup are we if > we down convert and use a low frequency spectrum analyzer ? > (downconverting with the best XTAL LO we can imagine). > > My target is microwaves and millimeter waves so I have to > down convert anyway, Or then I have to live with what my > spectrum analyzer show me (a tek 492, in my case). > > --- > > Rephrasing the question, how much better are the low frequency > spectrum analyzers comparing to the microwave spectrum > analysers (in phase noise I mean)? > > > Any comments ? > > Luis Cupido. > ct1dmk. > > P.S.(I know that I'm limites to 100Hz RBW with my 492... and > I would like also to measure closer than that ) > > Luis The latest spectrum analyser offerings from Agilent have similar phase noise floors for both the millimeter wave and low frequency spectrum analysers. However the low frequency analysers have a lower "flicker" noise corner. The noise floor of a good double balanced mixer is still 30-40dB lower than that a spectrum analyser. Thus you are stuck with using a low bandwidth phase lock loop to get down to the mixer noise floor. Alternatively a dual (first conversion uses analog mixers, 2nd conversion uses DSP techniques) conversion Costas receiver using 4 mixers and 4 ADCs should go down to -170dBc @ offsets of 100Hz or so when correlation techniques are employed. Its a pity the TSC5120A doesnt allow independent access to all 4 of its ADC inputs so a quad of external mixers can be employed to extend the technique to the millimeter wave region. All you need is 4 high resolution ADCs and an offset generator or 2. A couple of high end sound cards may be suitable at least for testing the concepts. Bruce From dougnhelen at moonlink.net Thu Aug 14 13:26:01 2008 From: dougnhelen at moonlink.net (Doug Millar) Date: Thu, 14 Aug 2008 10:26:01 -0700 Subject: [time-nuts] New 10mhz Distribution Amplifier Message-ID: <0K5L00L28PRHNVZ4@vms173005.mailsrvcs.net> Hi, A new 10mhz distribution amplifier is available at amateur prices. Jerry N7EME is producing them. His website is at http://jwmeng.com/model_RDA-6.html Doug K6JEY From bruce.griffiths at xtra.co.nz Thu Aug 14 17:52:29 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 15 Aug 2008 09:52:29 +1200 Subject: [time-nuts] New 10mhz Distribution Amplifier In-Reply-To: <0K5L00L28PRHNVZ4@vms173005.mailsrvcs.net> References: <0K5L00L28PRHNVZ4@vms173005.mailsrvcs.net> Message-ID: <48A4A91D.3050806@xtra.co.nz> Doug Millar wrote: > Hi, > A new 10mhz distribution amplifier is available at amateur prices. > Jerry N7EME is producing them. His website is at > http://jwmeng.com/model_RDA-6.html > Doug K6JEY > > > There's a few specifications missing: 1) input impedance and return loss. 2) output impedance and return loss 3) phase noise These are essential if one is to make a rational decision on the suitability of the distribution amplifier. The outputs and inputs appear to share a common ground. This would preclude its use in some setups without external means of providing the required isolation. The other question is does the device use AGC to set the output level? If it does the phase noise floor will almost inevitably be relatively high compared to the state of the art. Bruce From pe1rks at xs4all.nl Thu Aug 14 18:24:55 2008 From: pe1rks at xs4all.nl (S. Nestra) Date: Fri, 15 Aug 2008 00:24:55 +0200 Subject: [time-nuts] Datum FTS-4040A Cesium standard Message-ID: <48A4B0B7.8050206@xs4all.nl> Hi, I have a problem with a FTS-4040A standard, the LED major fault stays on forever. When I use the monitor program from Symmetricom I see that my OCXO stays cold and I have no Cesium oven voltage. The OCXO does feel warm so this one is warming up, I don't know if the cesium oven is warming up since I can't feel any heat from the CBT. I also don't see any current from the ION pump. After opening the unit I found a burnt resistor R1 on one board, I don't know what it's function is but I would like to know the value of this resistor so I can replace it. So here is my question: does anybody have any technical documentation for this unit and is it possible for someone to lookup this resistor in his standard so I know the value( pictures included for position). I think I have a power supply problem. I welcome all suggestions. Greets, Stijn Nestra Link for the pictures and the list of faults: http://82.95.123.226/fts4040a/ From richard at karlquist.com Thu Aug 14 18:37:11 2008 From: richard at karlquist.com (Rick Karlquist) Date: Thu, 14 Aug 2008 15:37:11 -0700 (PDT) Subject: [time-nuts] New 10mhz Distribution Amplifier In-Reply-To: <48A4A91D.3050806@xtra.co.nz> References: <0K5L00L28PRHNVZ4@vms173005.mailsrvcs.net> <48A4A91D.3050806@xtra.co.nz> Message-ID: <16702.192.25.142.225.1218753431.squirrel@webmail.sonic.net> Additional specs to consider: The return loss should be low for 10 MHz and the first 8 harmonics. The harmonic distortion should be low. The isolation between outputs should be high. The phase drift vs temperature should be low. The short term stability at 1 second should be good. The magnetic field susceptibility should be low. Line sidebands should be low. Compare, for example, the HP5087, a so-so design, to the output amplifier design in the 5071A cesium, as documented in my FCS paper in 1992. Huge difference in specs. The 5071A has 120 dB isolation between outputs. Rick Karlquist N6RK Bruce Griffiths wrote: > Doug Millar wrote: >> Hi, >> A new 10mhz distribution amplifier is available at amateur prices. >> Jerry N7EME is producing them. His website is at >> http://jwmeng.com/model_RDA-6.html >> Doug K6JEY >> >> >> > There's a few specifications missing: > > 1) input impedance and return loss. > > 2) output impedance and return loss > > 3) phase noise > > These are essential if one is to make a rational decision on the > suitability of the distribution amplifier. > > The outputs and inputs appear to share a common ground. > This would preclude its use in some setups without external means of > providing the required isolation. > > The other question is does the device use AGC to set the output level? > If it does the phase noise floor will almost inevitably be relatively > high compared to the state of the art. > > 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 Thu Aug 14 18:46:07 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 15 Aug 2008 10:46:07 +1200 Subject: [time-nuts] New 10mhz Distribution Amplifier In-Reply-To: <16702.192.25.142.225.1218753431.squirrel@webmail.sonic.net> References: <0K5L00L28PRHNVZ4@vms173005.mailsrvcs.net> <48A4A91D.3050806@xtra.co.nz> <16702.192.25.142.225.1218753431.squirrel@webmail.sonic.net> Message-ID: <48A4B5AF.4030707@xtra.co.nz> Rick Karlquist wrote: > Additional specs to consider: > > The return loss should be low for 10 MHz and the first 8 harmonics. > The harmonic distortion should be low. > The isolation between outputs should be high. > The phase drift vs temperature should be low. > The short term stability at 1 second should be good. > The magnetic field susceptibility should be low. > Line sidebands should be low. > > Compare, for example, the HP5087, a so-so design, to the > output amplifier design in the 5071A cesium, as documented > in my FCS paper in 1992. Huge difference in specs. The > 5071A has 120 dB isolation between outputs. > > Rick Karlquist N6RK > > > Rick Did you mean a high return loss or equivalently low reflection coefficient? The layout of the board in the picture is perhaps preliminary the input signal track to 3 of the output sections is a little too close to another track. Its hard to tell from the low res image but have thick film resistors been used? These can have excessive flicker noise thus increasing the close in phase noise above that possible with thin film resistors. Bruce From richard at karlquist.com Thu Aug 14 19:13:58 2008 From: richard at karlquist.com (Rick Karlquist) Date: Thu, 14 Aug 2008 16:13:58 -0700 (PDT) Subject: [time-nuts] New 10mhz Distribution Amplifier In-Reply-To: <48A4B5AF.4030707@xtra.co.nz> References: <0K5L00L28PRHNVZ4@vms173005.mailsrvcs.net> <48A4A91D.3050806@xtra.co.nz> <16702.192.25.142.225.1218753431.squirrel@webmail.sonic.net> <48A4B5AF.4030707@xtra.co.nz> Message-ID: <7609.192.25.142.225.1218755638.squirrel@webmail.sonic.net> I should have said the return loss should be "high" or "good" :-) Bruce Griffiths wrote: > Rick Karlquist wrote: >> Additional specs to consider: >> >> The return loss should be low for 10 MHz and the first 8 harmonics. >> The harmonic distortion should be low. >> The isolation between outputs should be high. >> The phase drift vs temperature should be low. >> The short term stability at 1 second should be good. >> The magnetic field susceptibility should be low. >> Line sidebands should be low. >> >> Compare, for example, the HP5087, a so-so design, to the >> output amplifier design in the 5071A cesium, as documented >> in my FCS paper in 1992. Huge difference in specs. The >> 5071A has 120 dB isolation between outputs. >> >> Rick Karlquist N6RK >> >> >> > Rick > > Did you mean a high return loss or equivalently low reflection > coefficient? > > The layout of the board in the picture is perhaps preliminary the input > signal track to 3 of the output sections is a little too close to > another track. > > Its hard to tell from the low res image but have thick film resistors > been used? > These can have excessive flicker noise thus increasing the close in > phase noise above that possible with thin film resistors. > > Bruce > > From rvassar at rob-vassar.com Thu Aug 14 19:24:46 2008 From: rvassar at rob-vassar.com (Robert Vassar) Date: Thu, 14 Aug 2008 18:24:46 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: <48A2BEC0.50004@quackers.net> <48A2C43D.8080800@mail.ua.pt> <48A2D924.3040809@hvsistemas.es> Message-ID: Good grief! That's not a microcontroller! :-) I like the MCS-51 family, but they're kind of goofy to program in C, and 8-bit. Upside, lots of vendors & variants, including the really nice SiLabs mixed signal chips made here in Austin. AVR is much nicer to code in C, and has great tool support, but they're single source, and I have read that Atmel is not always completely forthcoming in their errata. Arm... If you need something that can run Linux.... But why not just go for a Soekris board at that point? :-) Rob KC6OOM/5 On Aug 13, 2008, at 7:06 PM, Bob Paddock wrote: >> any ARM7 outperforms the best PIC in price and performance :) > > http://beagleboard.org/ > > Get them from DigiKey, $149. > > http://dkc1.digikey.com/us/mkt/beagleboard.html > > "The USB-powered Beagle Board is a low-cost, fan-less single board > > computer utilizing Texas Instruments' OMAP3530 [ARM] application > processor > > that unleashes laptop-like performance and > > expansion without the bulk, expense, or noise of typical desktop > machines. > > Beagle Board is based on an OMAP3530 application processor featuring > an ARM(R) Cortex?-A8 running at up to 600MHz and delivering over 1,200 > Dhrystone MIPS of performance via superscalar operation with highly > accurate branch prediction and 256KB of L2 cache. Focal to Beagle > Board experience is the high-speed USB 2.0 on-the-go (OTG) port that > can be utilized to provide power to the board or to deliver highly > flexible expansion. Standard PC peripherals can be connected to > Beagle Board using the USB with a mini-A to standard-A cable adapter, > DVI-D using an HDMI to DVI-D adapter, or through the MMC/SD/SDIO > connector enabling a complete desktop experience." > > > -- > http://www.wearablesmartsensors.com/ > http://www.softwaresafety.net/ > http://www.designer-iii.com/ > http://www.unusualresearch.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 bruce.griffiths at xtra.co.nz Thu Aug 14 19:44:50 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 15 Aug 2008 11:44:50 +1200 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: <48A2BEC0.50004@quackers.net> <48A2C43D.8080800@mail.ua.pt> <48A2D924.3040809@hvsistemas.es> Message-ID: <48A4C372.7090104@xtra.co.nz> Robert Vassar wrote: > > Good grief! That's not a microcontroller! :-) > > > > I like the MCS-51 family, but they're kind of goofy to program in C, > and 8-bit. Upside, lots of vendors & variants, including the really > nice SiLabs mixed signal chips made here in Austin. AVR is much > nicer to code in C, and has great tool support, but they're single > source, and I have read that Atmel is not always completely > forthcoming in their errata. > > > Arm... If you need something that can run Linux.... But why not just > go for a Soekris board at that point? :-) > > > Rob > KC6OOM/5 > > You can do substantially better by using a suitable FPGA board. One can create a hardware timestamp counter with multiple capture registers that wont wrap around in less than a week or more together with whatever simple processors required for decoding GPS receiver data. A simple 16 x2 character LCD display or similar is easily added for field readout. Keyboards and pushbuttons together with serial ports USB ports etc are often provided so communications with A PC for data retrieval /storage is readily possible. Bruce From magnus at rubidium.dyndns.org Thu Aug 14 20:17:21 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 15 Aug 2008 02:17:21 +0200 Subject: [time-nuts] New 10mhz Distribution Amplifier In-Reply-To: <7609.192.25.142.225.1218755638.squirrel@webmail.sonic.net> References: <0K5L00L28PRHNVZ4@vms173005.mailsrvcs.net> <48A4A91D.3050806@xtra.co.nz> <16702.192.25.142.225.1218753431.squirrel@webmail.sonic.net> <48A4B5AF.4030707@xtra.co.nz> <7609.192.25.142.225.1218755638.squirrel@webmail.sonic.net> Message-ID: <48A4CB11.3080004@rubidium.dyndns.org> Rick Karlquist wrote: > I should have said the return loss should be "high" or "good" :-) "high" works, "good" depends on the application. :-) I would look at the return loss curve in general. Cheers, Magnus From cupido at mail.ua.pt Thu Aug 14 20:55:13 2008 From: cupido at mail.ua.pt (Luis Cupido) Date: Fri, 15 Aug 2008 01:55:13 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A4199C.5010109@xtra.co.nz> References: <48A40F1C.4020800@mail.ua.pt> <48A4199C.5010109@xtra.co.nz> Message-ID: <48A4D3F1.3050007@mail.ua.pt> Bruce, tks for your reply. > The latest spectrum analyser offerings from Agilent have similar phase > noise floors for both the millimeter wave and low frequency spectrum > analysers. Yes, but kind of puzzles me a bit since I would be expecting phase noises more than 10x worst on a SA covering DC to 1GHz (+/-) (since the LO for this is an YIG oscillator circa 3GHz locked to a reference) comparing with an FFT analyzer that uses a few tens MHz sample rate. Assuming similar 10MHz reference oscillator the SA gets it multiplied by 300 while a low freq SA (preferably FFT) gets it multiplied by 10 maximum. How can they claim similar performance ?! --- Ok on the rest, tks. Luis Cupido. Bruce Griffiths wrote: > Luis > > The latest spectrum analyser offerings from Agilent have similar phase > noise floors for both the millimeter wave and low frequency spectrum > analysers. > However the low frequency analysers have a lower "flicker" noise corner. > > The noise floor of a good double balanced mixer is still 30-40dB lower > than that a spectrum analyser. > > Thus you are stuck with using a low bandwidth phase lock loop to get > down to the mixer noise floor. > > Alternatively a dual (first conversion uses analog mixers, 2nd > conversion uses DSP techniques) conversion Costas receiver using 4 > mixers and 4 ADCs should go down to -170dBc @ offsets of 100Hz or so > when correlation techniques are employed. Its a pity the TSC5120A doesnt > allow independent access to all 4 of its ADC inputs so a quad of > external mixers can be employed to extend the technique to the > millimeter wave region. > > All you need is 4 high resolution ADCs and an offset generator or 2. > A couple of high end sound cards may be suitable at least for testing > the concepts. > > 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 Thu Aug 14 21:47:37 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 15 Aug 2008 13:47:37 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A4D3F1.3050007@mail.ua.pt> References: <48A40F1C.4020800@mail.ua.pt> <48A4199C.5010109@xtra.co.nz> <48A4D3F1.3050007@mail.ua.pt> Message-ID: <48A4E039.1070900@xtra.co.nz> Luis Cupido wrote: > Bruce, tks for your reply. > > > The latest spectrum analyser offerings from Agilent have similar phase > > noise floors for both the millimeter wave and low frequency spectrum > > analysers. > > Yes, but kind of puzzles me a bit since I would > be expecting phase noises more than 10x worst on a > SA covering DC to 1GHz (+/-) > (since the LO for this is an YIG oscillator circa 3GHz locked to a > reference) > comparing with an FFT analyzer that uses a few tens MHz sample rate. > > Assuming similar 10MHz reference oscillator the SA > gets it multiplied by 300 while a low freq SA (preferably FFT) > gets it multiplied by 10 maximum. > How can they claim similar performance ?! > --- > > Ok on the rest, tks. > > > Luis Cupido. > > > Luis Perhaps the local oscillator isn't the limiting factor for the low frequency analysers. The claimed noise floor is in the vicinity (within 10dB) of -120dBc/Hz for the analysers for which I checked the specs. If the 10MHz reference has a phase noise floor of around -160dBc/Hz this is only degraded by 50dB or so to -110dBc/Hz when multiplied by 300. The YIG oscillator phase noise floor may perhaps be a little better than this. However, since state of the art ADCs have a phase noise floor of around -150dBc/Hz one would expect a lower phase noise floor from the lower frequency spectrum analysers. Surely there's an FFT based spectrum analyser out there wit this level of performance. Bruce From jmiles at pop.net Thu Aug 14 21:59:25 2008 From: jmiles at pop.net (John Miles) Date: Thu, 14 Aug 2008 18:59:25 -0700 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A4D3F1.3050007@mail.ua.pt> Message-ID: > Yes, but kind of puzzles me a bit since I would > be expecting phase noises more than 10x worst on a > SA covering DC to 1GHz (+/-) > (since the LO for this is an YIG oscillator circa 3GHz locked to a > reference) > comparing with an FFT analyzer that uses a few tens MHz sample rate. Phase noise is slightly better on the FFT-based analyzers. The RF signal still has to be downconverted to baseband in the FFT analyzers, and they still use YTO synthesizers to do that as far as I'm aware. The difference, with an FFT-based analyzer, is that the synthesizer does not have to be designed with compromises like 1 Hz tuning resolution. It's easier and cheaper to build a clean microwave LO if its tuning resolution is 10 MHz or so. But there are still no free lunches to be had. > Assuming similar 10MHz reference oscillator the SA > gets it multiplied by 300 while a low freq SA (preferably FFT) > gets it multiplied by 10 maximum. > How can they claim similar performance ?! Typically there is an intermediate synthesis stage in the first LO, where the 10 MHz reference is multiplied to a few hundred MHz in a very clean loop. The first LO itself tunes from 2 GHz to (whatever), using a relatively-small 'N' factor. Again this is still true of FFT-based designs; it's just that the 1st LO's intermediate synthesizer can be designed without compromises like noisy subloops or spur-prone DDSs, or a tunable 2nd LO. Looking at figure 1 in the PSA brochure: http://cp.literature.agilent.com/litweb/pdf/5980-1284E.pdf ... it looks like they are still using a high first IF, at 2 GHz or so, because the LO noise profile still looks like a conventional spectrum analyzer. They don't show a second conversion in their PSA series block diagram here: http://cp.literature.agilent.com/litweb/pdf/5980-1283E.pdf (page 15) ... but you can tell it's still there, because there's a 321.4 MHz IF output on the back panel, just like their older analog models. They are either using a traditional multiconversion receiver or an undersampling ADC. My bet would be on the former topology because it still offers the best digitizing performance. -- john, KE5FX From smace at intt.net Thu Aug 14 22:00:46 2008 From: smace at intt.net (Scott Mace) Date: Thu, 14 Aug 2008 21:00:46 -0500 Subject: [time-nuts] thunderbolt for ntpd or gpsd In-Reply-To: <48559045.4080703@stnhbr.com> References: <200806151145.58089.w.knowles@xtra.co.nz> <48559045.4080703@stnhbr.com> Message-ID: <48A4E34E.5080700@intt.net> I found that on the two FatPPS units I have, pin 2 on the female DE-9 connector is tied to the DC-IN. This was causing noise from the thunderbolt RS-232 TX to get into the PPS output. It basically made it totally unusable. I removed R4 since I use DTR for power and it works perfectly. Scott Tim Cwik wrote: > Wayne Knowles wrote: >> Tim, Chris, >> >> Over a month ago I experimented with getting GPSD and the Tunderbolt working >> together. >> I quickly added support for the missing TSIP packet types, and was able to get >> xgps to display lat, long, time and constellation status. I did manage to >> get NTP to work, have not invested the time into getting the 1PPS signal >> working under FreeBSD yet. >> >> I have attached my patches against the gpsd source repository. Note that I >> did not invest much time understanding the internals of gpsd beforehand so >> some aspects may not be fully implemented. >> >> > Thanks Wayne and Chris and Chris. > > I have discovered the even though cgps does not report position or time > using the Thunderbolt, the stock gpsd is getting enough timing data to > update ntp. Gpsd is selected as the sys.peer with a jitter of about .8. > It looks like the PPS pulse is too narrow to be detected on DCD, I am > going to investigate a pulse stretcher available from TAPR > http://tapr.org/kits_fatpps.html and will see if that helps. FWIW, > Centos 5.1 selinux allows gpsd to update the ntp shared memory segment > out of the box. > > > 73, > > > _______________________________________________ > time-nuts mailing list -- 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 Aug 14 22:05:42 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Fri, 15 Aug 2008 14:05:42 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A4E039.1070900@xtra.co.nz> References: <48A40F1C.4020800@mail.ua.pt> <48A4199C.5010109@xtra.co.nz> <48A4D3F1.3050007@mail.ua.pt> <48A4E039.1070900@xtra.co.nz> Message-ID: <48A4E476.1060508@xtra.co.nz> Bruce Griffiths wrote: > Luis Cupido wrote: > >> Bruce, tks for your reply. >> >> > The latest spectrum analyser offerings from Agilent have similar phase >> > noise floors for both the millimeter wave and low frequency spectrum >> > analysers. >> >> Yes, but kind of puzzles me a bit since I would >> be expecting phase noises more than 10x worst on a >> SA covering DC to 1GHz (+/-) >> (since the LO for this is an YIG oscillator circa 3GHz locked to a >> reference) >> comparing with an FFT analyzer that uses a few tens MHz sample rate. >> >> Assuming similar 10MHz reference oscillator the SA >> gets it multiplied by 300 while a low freq SA (preferably FFT) >> gets it multiplied by 10 maximum. >> How can they claim similar performance ?! >> --- >> >> Ok on the rest, tks. >> >> >> Luis Cupido. >> >> >> >> Luis The R+S FMU36 has a phase noise floor of around -143dBc/Hz (offset > 10kHz) with a 10MHz input. Whereas the R+S FSU67 has a phase noise floor of around -133dBcdBc/Hz (offset = 10kHz) with a 640Mhz input. There is a definite improvement at lower frequencies but not quite as much as one might have expected. Bruce From jmiles at pop.net Thu Aug 14 22:17:27 2008 From: jmiles at pop.net (John Miles) Date: Thu, 14 Aug 2008 19:17:27 -0700 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A4E039.1070900@xtra.co.nz> Message-ID: > Perhaps the local oscillator isn't the limiting factor for the low > frequency analysers. > The claimed noise floor is in the vicinity (within 10dB) of -120dBc/Hz > for the analysers for which I checked the specs. > > If the 10MHz reference has a phase noise floor of around -160dBc/Hz > this is only degraded by 50dB or so to -110dBc/Hz when multiplied by 300. > The YIG oscillator phase noise floor may perhaps be a little better than > this. > > However, since state of the art ADCs have a phase noise floor of around > -150dBc/Hz one would expect a lower phase noise floor from the lower > frequency spectrum analysers. > Surely there's an FFT based spectrum analyser out there wit this level > of performance. In the 80s-era analyzers like the 8566, the sampler used in the YTO loop is what hoses you in the end. You can make substantial improvements in the noise performance of both the reference and the intermediate ("M/N") synthesizer, but you hit the sampler's noise floor at around -105 to -110 dBc/Hz. It would be interesting to learn if Agilent's high-end PSA series FFT analyzers still use a sampler-based YTO loop, or if they are now using traditional dividers and phase detectors. Something tells me the service manuals no longer contain schematics and dissertations. :) It is true that 10 MHz @ -160 dBc/Hz * 300 = 3000 MHz @ -110 dBc/Hz, but the devil's in the details. The broadband floor of a 100 MHz reference is no worse than that of a 10 MHz reference, so an obvious optimization is to lock a 100 MHz oscillator to the 10 MHz reference and use *that* as the reference. This gives you more like -130 dBc/Hz in theory. But then you have to tune the reference, so there has to be a synthesizer to drive the final YTO loop. That, assuming you're not limited by sampler/PD noise, is where the majority of the noise comes from. Most synthesizers regardless of technology still end up with broadband floors in the -150 dBc/Hz neighborhood, so now you're back to circa -120 dBc/Hz inband... which is what the PSA-series spec sheets show. It's an interesting business. I spent a lot of time redesigning my 8566B's LO synthesizer, until I realized two things: 1) the YTO sampler noise floor was the real problem, and I didn't feel up to redesigning *that* loop; and 2) lowering the PN floor would probably reveal spurs that the original designers never knew/cared about, which would lead to even more hair-pulling. It would certainly be possible to design a cleaner analyzer LO than the PSA has, but it would cost more, the effort would go unappreciated by most users, and worse, Agilent would sell fewer E5500 outfits! -- john, KE5FX From jmiles at pop.net Thu Aug 14 22:25:22 2008 From: jmiles at pop.net (John Miles) Date: Thu, 14 Aug 2008 19:25:22 -0700 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A4E476.1060508@xtra.co.nz> Message-ID: > The R+S FMU36 has a phase noise floor of around -143dBc/Hz (offset > > 10kHz) with a 10MHz input. > Whereas the R+S FSU67 has a phase noise floor of around -133dBcdBc/Hz > (offset = 10kHz) with a 640Mhz input. > > There is a definite improvement at lower frequencies but not quite as > much as one might have expected. The *floor* of a YTO loop is not very dependent on the carrier frequency, as the loop bandwidth usually ends up less than 100 kHz. It's more interesting to look at the inband noise at 1 - 10 kHz offsets. The FSU67 looks great in that department: http://www.testbuyer.com/pdf/specs.cfm?pdf_id=56025C0EC7 Looks like it spanks the Agilent by a good 10 dBc/Hz. I want one. :) -- john, KE5FX From jmiles at pop.net Thu Aug 14 22:29:48 2008 From: jmiles at pop.net (John Miles) Date: Thu, 14 Aug 2008 19:29:48 -0700 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: Message-ID: > Most synthesizers regardless of technology still end up with broadband > floors in the -150 dBc/Hz neighborhood, so now you're back to circa -120 > dBc/Hz inband... which is what the PSA-series spec sheets show. I didn't phrase that very well; I meant to say that the broadband floor of your phase detector/dividers/other components is what keeps you from being able to drive the final YTO loop at -160 dBc/Hz even though the reference may be even cleaner than that. -- john, KE5FX From didier at cox.net Thu Aug 14 22:51:34 2008 From: didier at cox.net (Didier Juges) Date: Thu, 14 Aug 2008 21:51:34 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: <48A2BEC0.50004@quackers.net> <48A2C43D.8080800@mail.ua.pt><48A2D924.3040809@hvsistemas.es> Message-ID: <038e01c8fe81$d4a99920$04000100@didierhp> I am not sure what you mean about the 8051 being goofy to program in C. Aside from the bit variable type, the Special Function Register declarations and the memory types (data, idata and xdata), which you only deal with one time (when declaring variables) and which you can even ignore in many applications (the compiler can take care of it, as long as you are not pushing the limits of the chip's capabilities), the code itself is pure C. The 8051 is considerably easier to program in C than in assembly, and there are several very mature C compilers for the 8051. On the other hand, the ACR being supported by gcc certainly gives it an edge in that area. I use SDCC with the 8051, and it does a very good job. It is actively developped and maintained as a sourceforge project. I routinely compile and run my 8051 C code under gcc on the pc because it's easier to have multiple test cases to make sure the functions do what I think they do... All I need is a few declarations to resolve bit, data, idata and xdata and bingo. Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Vassar > Sent: Thursday, August 14, 2008 6:25 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] I want a good micro-controller > > > > > Good grief! That's not a microcontroller! :-) > > > > I like the MCS-51 family, but they're kind of goofy to > program in C, and 8-bit. Upside, lots of vendors & variants, > including the really nice SiLabs mixed signal chips made here > in Austin. AVR is much nicer to code in C, and has great > tool support, but they're single source, and I have read that > Atmel is not always completely forthcoming in their errata. > > > Arm... If you need something that can run Linux.... But why > not just go for a Soekris board at that point? :-) > > > Rob > KC6OOM/5 > > > On Aug 13, 2008, at 7:06 PM, Bob Paddock wrote: > > >> any ARM7 outperforms the best PIC in price and performance :) > > > > http://beagleboard.org/ > > > > Get them from DigiKey, $149. > > > > http://dkc1.digikey.com/us/mkt/beagleboard.html > > > > "The USB-powered Beagle Board is a low-cost, fan-less single board > > > > computer utilizing Texas Instruments' OMAP3530 [ARM] application > > processor > > > > that unleashes laptop-like performance and > > > > expansion without the bulk, expense, or noise of typical desktop > > machines. > > > > Beagle Board is based on an OMAP3530 application processor > featuring > > an ARM(R) CortexT-A8 running at up to 600MHz and delivering > over 1,200 > > Dhrystone MIPS of performance via superscalar operation with highly > > accurate branch prediction and 256KB of L2 cache. Focal to Beagle > > Board experience is the high-speed USB 2.0 on-the-go (OTG) > port that > > can be utilized to provide power to the board or to deliver highly > > flexible expansion. Standard PC peripherals can be connected to > > Beagle Board using the USB with a mini-A to standard-A > cable adapter, > > DVI-D using an HDMI to DVI-D adapter, or through the MMC/SD/SDIO > > connector enabling a complete desktop experience." > > > > > > -- > > http://www.wearablesmartsensors.com/ > > http://www.softwaresafety.net/ > > http://www.designer-iii.com/ > > http://www.unusualresearch.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. > From w4oa at vibroplex.com Thu Aug 14 23:30:13 2008 From: w4oa at vibroplex.com (F Mitchell) Date: Thu, 14 Aug 2008 22:30:13 -0500 Subject: [time-nuts] Olympic time standard? Message-ID: Is there a common time standard that all of the timed Olympic events are referenced to? I know that Omega provides the timing, their logo is on every computer that you see. If there is a common reference, how is it distributed to all of the events? Mitch From magnus at rubidium.dyndns.org Fri Aug 15 04:39:05 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 15 Aug 2008 10:39:05 +0200 Subject: [time-nuts] Olympic time standard? In-Reply-To: References: Message-ID: <48A540A9.1060204@rubidium.dyndns.org> F Mitchell wrote: > > > Is there a common time standard that all of the timed > > Olympic events are referenced to? I know that Omega > > provides the timing, their logo is on every computer > > that you see. If there is a common reference, how is > > it distributed to all of the events? The Omega site discloses very little detail, rather statistics on how much gear and staff there is. I could hand them a 2.048 MHz on each venue, but I doubt that they would need it. They could have got more timing-oriented time if they would have asked for it, but they haven't. I rather suspect that for most venues they have local clocks and they have TV generators so the clocks of the screen come from there anyway. They mostly need relative timing anyway, so I don't suspect a distribution network. The only distribution they need is the TV pictures and it's there. Cheers, Magnus From martyn at ptsyst.com Fri Aug 15 04:31:18 2008 From: martyn at ptsyst.com (Martyn Smith) Date: Fri, 15 Aug 2008 09:31:18 +0100 Subject: [time-nuts] New 10 MHz Distribution Amplifier In-Reply-To: References: Message-ID: <14E529E1B4BD4A9AB10351EE477743A3@MartynDesktop> I read with interest about the new 10 MHz distribution amplifier. But I agree with everyone, it's the specs that are missing that are important. But I wanted to take one comment up about AGC. My company makes a nice distribution amplifier and we do have AGC. The nice thing here is that a +7 dBm input (e.g PRS10 output) will give you up to +13 dBm output. Despite the AGC we still achieve good phase noise (-135 dBc/Hz @ 1 Hz with a -168 dBc noise floor) together with 130 dB isolation and 10 ps/C phase stability. I suspect this low cost unit has a -140 or -150 dBc noise floor. But our unit costs a lot more than this low cost design, so maybe I'm not being fair in comparing. www.ptsyst.com/DA1-100-10-B.pdf has all our specifications. I could probably talk our sales manager in a once off big discount for time nuts readers, but I suspect it would still be out of the range of amateurs. Send me an email if you are interested (martyn at ptsyst.com) Martyn From martyn at ptsyst.com Fri Aug 15 04:44:58 2008 From: martyn at ptsyst.com (Martyn Smith) Date: Fri, 15 Aug 2008 09:44:58 +0100 Subject: [time-nuts] Importing into EEC In-Reply-To: References: Message-ID: <63593424D48240B7ADB6FAED64ECD187@MartynDesktop> Just wanted to remind everyone it's illegal to import any electronic devices into Europe without them having a CE mark. I see there have been many projects like the Jackson Labs unit that have been imported into Europe. This is illegal. I don't mean to knick pick, but it costs our company about $10000 to CE mark a product. And if we add one small option, it must be CE marked again. To the small manufacturer, this kills us and doesn't allow us to offer low prices. Steve Best Regards Martyn This Email is from: Martyn Smith Precision Test Systems LTD Tel: +44 (0) 1245 329608 Email: martyn at ptsyst.com Web: www.ptsyst.com NOTICE - This message contains legally privileged and confidential information intended only for the use of the addressee named above. If you are not the intended recipient of this message, you are hereby notified that you must not disseminate, distribute, copy or take any action in reliance on it. If you have received this message in error, please notify Precision Test Systems LTD. This communication represents the originator's personal views and opinions, which do not necessarily reflect those of Precision Test Systems Ltd. from whom it emanates. Further, Precision Test Systems Ltd. will not be held responsible for its contents and/or attachments, if the communication contravenes the rules of Precision Test Systems Ltd's email policy. ----- Original Message ----- From: To: Sent: Friday, August 15, 2008 1:17 AM Subject: time-nuts Digest, Vol 49, Issue 32 > Send time-nuts mailing list submissions to > time-nuts at febo.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > or, via email, send a message with subject or body 'help' to > time-nuts-request at febo.com > > You can reach the person managing the list at > time-nuts-owner at febo.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > > Today's Topics: > > 1. New 10mhz Distribution Amplifier (Doug Millar) > 2. Re: New 10mhz Distribution Amplifier (Bruce Griffiths) > 3. Datum FTS-4040A Cesium standard (S. Nestra) > 4. Re: New 10mhz Distribution Amplifier (Rick Karlquist) > 5. Re: New 10mhz Distribution Amplifier (Bruce Griffiths) > 6. Re: New 10mhz Distribution Amplifier (Rick Karlquist) > 7. Re: I want a good micro-controller (Robert Vassar) > 8. Re: I want a good micro-controller (Bruce Griffiths) > 9. Re: New 10mhz Distribution Amplifier (Magnus Danielson) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 14 Aug 2008 10:26:01 -0700 > From: Doug Millar > Subject: [time-nuts] New 10mhz Distribution Amplifier > To: > Message-ID: <0K5L00L28PRHNVZ4 at vms173005.mailsrvcs.net> > Content-Type: text/plain; charset=us-ascii; format=flowed > > > Hi, > A new 10mhz distribution amplifier is available at amateur prices. > Jerry N7EME is producing them. His website is at > http://jwmeng.com/model_RDA-6.html > Doug K6JEY > > > > > ------------------------------ > > Message: 2 > Date: Fri, 15 Aug 2008 09:52:29 +1200 > From: Bruce Griffiths > Subject: Re: [time-nuts] New 10mhz Distribution Amplifier > To: Discussion of precise time and frequency measurement > > Message-ID: <48A4A91D.3050806 at xtra.co.nz> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Doug Millar wrote: >> Hi, >> A new 10mhz distribution amplifier is available at amateur prices. >> Jerry N7EME is producing them. His website is at >> http://jwmeng.com/model_RDA-6.html >> Doug K6JEY >> >> >> > There's a few specifications missing: > > 1) input impedance and return loss. > > 2) output impedance and return loss > > 3) phase noise > > These are essential if one is to make a rational decision on the > suitability of the distribution amplifier. > > The outputs and inputs appear to share a common ground. > This would preclude its use in some setups without external means of > providing the required isolation. > > The other question is does the device use AGC to set the output level? > If it does the phase noise floor will almost inevitably be relatively > high compared to the state of the art. > > Bruce > > > > ------------------------------ > > Message: 3 > Date: Fri, 15 Aug 2008 00:24:55 +0200 > From: "S. Nestra" > Subject: [time-nuts] Datum FTS-4040A Cesium standard > To: time-nuts at febo.com > Message-ID: <48A4B0B7.8050206 at xs4all.nl> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi, > > I have a problem with a FTS-4040A standard, the LED major fault stays on > forever. > When I use the monitor program from Symmetricom I see that my OCXO stays > cold and I have no Cesium oven voltage. The OCXO does feel warm so this > one is warming up, I don't know if the cesium oven is warming up since I > can't feel any heat from the CBT. > I also don't see any current from the ION pump. > After opening the unit I found a burnt resistor R1 on one board, I don't > know what it's function is but I would like to know the value of this > resistor so I can replace it. > So here is my question: does anybody have any technical documentation > for this unit and is it possible for someone to lookup this resistor in > his standard so I know the value( pictures included for position). > I think I have a power supply problem. > I welcome all suggestions. > > Greets, > > Stijn Nestra > > Link for the pictures and the list of > faults: http://82.95.123.226/fts4040a/ > > > > > ------------------------------ > > Message: 4 > Date: Thu, 14 Aug 2008 15:37:11 -0700 (PDT) > From: "Rick Karlquist" > Subject: Re: [time-nuts] New 10mhz Distribution Amplifier > To: "Discussion of precise time and frequency measurement" > > Message-ID: > <16702.192.25.142.225.1218753431.squirrel at webmail.sonic.net> > Content-Type: text/plain;charset=iso-8859-1 > > Additional specs to consider: > > The return loss should be low for 10 MHz and the first 8 harmonics. > The harmonic distortion should be low. > The isolation between outputs should be high. > The phase drift vs temperature should be low. > The short term stability at 1 second should be good. > The magnetic field susceptibility should be low. > Line sidebands should be low. > > Compare, for example, the HP5087, a so-so design, to the > output amplifier design in the 5071A cesium, as documented > in my FCS paper in 1992. Huge difference in specs. The > 5071A has 120 dB isolation between outputs. > > Rick Karlquist N6RK > > > Bruce Griffiths wrote: >> Doug Millar wrote: >>> Hi, >>> A new 10mhz distribution amplifier is available at amateur prices. >>> Jerry N7EME is producing them. His website is at >>> http://jwmeng.com/model_RDA-6.html >>> Doug K6JEY >>> >>> >>> >> There's a few specifications missing: >> >> 1) input impedance and return loss. >> >> 2) output impedance and return loss >> >> 3) phase noise >> >> These are essential if one is to make a rational decision on the >> suitability of the distribution amplifier. >> >> The outputs and inputs appear to share a common ground. >> This would preclude its use in some setups without external means of >> providing the required isolation. >> >> The other question is does the device use AGC to set the output level? >> If it does the phase noise floor will almost inevitably be relatively >> high compared to the state of the art. >> >> 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. >> >> > > > > > > ------------------------------ > > Message: 5 > Date: Fri, 15 Aug 2008 10:46:07 +1200 > From: Bruce Griffiths > Subject: Re: [time-nuts] New 10mhz Distribution Amplifier > To: richard at karlquist.com, Discussion of precise time and frequency > measurement > Message-ID: <48A4B5AF.4030707 at xtra.co.nz> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Rick Karlquist wrote: >> Additional specs to consider: >> >> The return loss should be low for 10 MHz and the first 8 harmonics. >> The harmonic distortion should be low. >> The isolation between outputs should be high. >> The phase drift vs temperature should be low. >> The short term stability at 1 second should be good. >> The magnetic field susceptibility should be low. >> Line sidebands should be low. >> >> Compare, for example, the HP5087, a so-so design, to the >> output amplifier design in the 5071A cesium, as documented >> in my FCS paper in 1992. Huge difference in specs. The >> 5071A has 120 dB isolation between outputs. >> >> Rick Karlquist N6RK >> >> >> > Rick > > Did you mean a high return loss or equivalently low reflection > coefficient? > > The layout of the board in the picture is perhaps preliminary the input > signal track to 3 of the output sections is a little too close to > another track. > > Its hard to tell from the low res image but have thick film resistors > been used? > These can have excessive flicker noise thus increasing the close in > phase noise above that possible with thin film resistors. > > Bruce > > > > ------------------------------ > > Message: 6 > Date: Thu, 14 Aug 2008 16:13:58 -0700 (PDT) > From: "Rick Karlquist" > Subject: Re: [time-nuts] New 10mhz Distribution Amplifier > To: "Bruce Griffiths" > Cc: Discussion of precise time and frequency measurement > > Message-ID: > <7609.192.25.142.225.1218755638.squirrel at webmail.sonic.net> >Content-Type: text/plain;charset=iso-8859-1 > > I should have said the return loss should be "high" or "good" :-) > > Bruce Griffiths wrote: >> Rick Karlquist wrote: >>> Additional specs to consider: >>> >>> The return loss should be low for 10 MHz and the first 8 harmonics. >>> The harmonic distortion should be low. >>> The isolation between outputs should be high. >>> The phase drift vs temperature should be low. >>> The short term stability at 1 second should be good. >>> The magnetic field susceptibility should be low. >>> Line sidebands should be low. >>> >>> Compare, for example, the HP5087, a so-so design, to the >>> output amplifier design in the 5071A cesium, as documented >>> in my FCS paper in 1992. Huge difference in specs. The >>> 5071A has 120 dB isolation between outputs. >>> >>> Rick Karlquist N6RK >>> >>> >>> >> Rick >> >> Did you mean a high return loss or equivalently low reflection >> coefficient? >> >> The layout of the board in the picture is perhaps preliminary the input >> signal track to 3 of the output sections is a little too close to >> another track. >> >> Its hard to tell from the low res image but have thick film resistors >> been used? >> These can have excessive flicker noise thus increasing the close in >> phase noise above that possible with thin film resistors. >> >> Bruce >> >> > > > > > > ------------------------------ > > Message: 7 > Date: Thu, 14 Aug 2008 18:24:46 -0500 > From: Robert Vassar > Subject: Re: [time-nuts] I want a good micro-controller > To: Discussion of precise time and frequency measurement > > Message-ID: > Content-Type: text/plain; charset=WINDOWS-1252; delsp=yes; > format=flowed > > > > > Good grief! That's not a microcontroller! :-) > > > > I like the MCS-51 family, but they're kind of goofy to program in C, > and 8-bit. Upside, lots of vendors & variants, including the really > nice SiLabs mixed signal chips made here in Austin. AVR is much > nicer to code in C, and has great tool support, but they're single > source, and I have read that Atmel is not always completely > forthcoming in their errata. > > > Arm... If you need something that can run Linux.... But why not just > go for a Soekris board at that point? :-) > > > Rob > KC6OOM/5 > > > On Aug 13, 2008, at 7:06 PM, Bob Paddock wrote: > >>> any ARM7 outperforms the best PIC in price and performance :) >> >> http://beagleboard.org/ >> >> Get them from DigiKey, $149. >> >> http://dkc1.digikey.com/us/mkt/beagleboard.html >> >> "The USB-powered Beagle Board is a low-cost, fan-less single board >> >> computer utilizing Texas Instruments' OMAP3530 [ARM] application >> processor >> >> that unleashes laptop-like performance and >> >> expansion without the bulk, expense, or noise of typical desktop >> machines. >> >> Beagle Board is based on an OMAP3530 application processor featuring >> an ARM(R) Cortex?-A8 running at up to 600MHz and delivering over 1,200 >> Dhrystone MIPS of performance via superscalar operation with highly >> accurate branch prediction and 256KB of L2 cache. Focal to Beagle >> Board experience is the high-speed USB 2.0 on-the-go (OTG) port that >> can be utilized to provide power to the board or to deliver highly >> flexible expansion. Standard PC peripherals can be connected to >> Beagle Board using the USB with a mini-A to standard-A cable adapter, >> DVI-D using an HDMI to DVI-D adapter, or through the MMC/SD/SDIO >> connector enabling a complete desktop experience." >> >> >> -- >> http://www.wearablesmartsensors.com/ >> http://www.softwaresafety.net/ >> http://www.designer-iii.com/ >> http://www.unusualresearch.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. > > > > > ------------------------------ > > Message: 8 > Date: Fri, 15 Aug 2008 11:44:50 +1200 > From: Bruce Griffiths > Subject: Re: [time-nuts] I want a good micro-controller > To: Discussion of precise time and frequency measurement > > Message-ID: <48A4C372.7090104 at xtra.co.nz> > Content-Type: text/plain; charset=windows-1252; format=flowed > > Robert Vassar wrote: >> >> Good grief! That's not a microcontroller! :-) >> >> >> >> I like the MCS-51 family, but they're kind of goofy to program in C, >> and 8-bit. Upside, lots of vendors & variants, including the really >> nice SiLabs mixed signal chips made here in Austin. AVR is much >> nicer to code in C, and has great tool support, but they're single >> source, and I have read that Atmel is not always completely >> forthcoming in their errata. >> >> >> Arm... If you need something that can run Linux.... But why not just >> go for a Soekris board at that point? :-) >> >> >> Rob >> KC6OOM/5 >> >> > You can do substantially better by using a suitable FPGA board. > One can create a hardware timestamp counter with multiple capture > registers that wont wrap around in less than a week or more together > with whatever simple processors required for decoding GPS receiver data. > A simple 16 x2 character LCD display or similar is easily added for > field readout. Keyboards and pushbuttons together with serial ports USB > ports etc are often provided so communications with A PC for data > retrieval /storage is readily possible. > > Bruce > > > > ------------------------------ > > Message: 9 > Date: Fri, 15 Aug 2008 02:17:21 +0200 > From: Magnus Danielson > Subject: Re: [time-nuts] New 10mhz Distribution Amplifier > To: richard at karlquist.com, Discussion of precise time and frequency > measurement > Message-ID: <48A4CB11.3080004 at rubidium.dyndns.org> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Rick Karlquist wrote: >> I should have said the return loss should be "high" or "good" :-) > > "high" works, "good" depends on the application. :-) > > I would look at the return loss curve in general. > > Cheers, > Magnus > > > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > time-nuts at febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 49, Issue 32 > ***************************************** > From phk at phk.freebsd.dk Fri Aug 15 04:46:26 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 08:46:26 +0000 Subject: [time-nuts] Olympic time standard? In-Reply-To: Your message of "Fri, 15 Aug 2008 10:39:05 +0200." <48A540A9.1060204@rubidium.dyndns.org> Message-ID: <2098.1218789986@critter.freebsd.dk> In message <48A540A9.1060204 at rubidium.dyndns.org>, Magnus Danielson writes: >F Mitchell wrote: >> Is there a common time standard that all of the timed >> Olympic events are referenced to? I belive it is a requirement that there be no external inputs (including power!) to the timing equipment, and therefore I would expect local OCXO's. 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 Fri Aug 15 04:49:19 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 08:49:19 +0000 Subject: [time-nuts] Importing into EEC In-Reply-To: Your message of "Fri, 15 Aug 2008 09:44:58 +0100." <63593424D48240B7ADB6FAED64ECD187@MartynDesktop> Message-ID: <2121.1218790159@critter.freebsd.dk> In message <63593424D48240B7ADB6FAED64ECD187 at MartynDesktop>, "Martyn Smith" wri tes: >Just wanted to remind everyone it's illegal to import any electronic devices >into Europe without them having a CE mark. That is not true. It is illegal to *sell* things without CE marks to the unwashed public, but you are allowed to import for personal use. In addition there are a vast array of exemptions, including professional test & measurement equipment. Furthermore, anything constructed before the CE mark requirement came into force in their local country are OK. >I see there have been many projects like the Jackson Labs unit that have >been imported into Europe. This is illegal. No, it is not, stop spreading FUD. 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 Fri Aug 15 05:12:55 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Fri, 15 Aug 2008 11:12:55 +0200 (CEST) Subject: [time-nuts] Olympic time standard? In-Reply-To: <2098.1218789986@critter.freebsd.dk> References: <2098.1218789986@critter.freebsd.dk> Message-ID: <80838a2edf28da2fb176d5f10273ccd3.squirrel@rubidium.dyndns.org> > In message <48A540A9.1060204 at rubidium.dyndns.org>, Magnus Danielson > writes: >>F Mitchell wrote: > >>> Is there a common time standard that all of the timed >>> Olympic events are referenced to? > > I belive it is a requirement that there be no external inputs > (including power!) to the timing equipment, and therefore I would > expect local OCXO's. Haven't heard about that requirement, but local OCXO's should be good enought. I suspect local power with UPS would be a working deal these days for the power. Cheers, Magnus From rexa at sonic.net Fri Aug 15 05:39:34 2008 From: rexa at sonic.net (Rex) Date: Fri, 15 Aug 2008 02:39:34 -0700 Subject: [time-nuts] Importing into EEC In-Reply-To: <63593424D48240B7ADB6FAED64ECD187@MartynDesktop> References: <63593424D48240B7ADB6FAED64ECD187@MartynDesktop> Message-ID: <48A54ED6.2050602@sonic.net> Martyn Smith wrote: > I don't mean to knick pick, but ... > I assume you didn't mean to nitpick either. Sorry. Not really important. I know it's bad form to criticize grammar on the internet but it caught my attention. Don't get me started on there, their and they're. From df6jb at ulrich-bangert.de Fri Aug 15 05:43:40 2008 From: df6jb at ulrich-bangert.de (Ulrich Bangert) Date: Fri, 15 Aug 2008 11:43:40 +0200 Subject: [time-nuts] New 10mhz Distribution Amplifier In-Reply-To: <16702.192.25.142.225.1218753431.squirrel@webmail.sonic.net> Message-ID: Rick, > Compare, for example, the HP5087, a so-so design, to the > output amplifier design in the 5071A cesium, as documented > in my FCS paper in 1992. Huge difference in specs. The > 5071A has 120 dB isolation between outputs. If I look at your FCS92 paper and specially to figures 5 and 6: Do I understand you correct in the sense that you are proposing a less analogue and more digital styled distribution amplifier with a near-sine construction from an digital clock and analogue output filtering for every output or are you just refering alone to the triangle amplifier building blocks to be seen in figure 5? 73s Ulrich, DF6JB > -----Ursprungliche Nachricht----- > Von: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] Im Auftrag von Rick Karlquist > Gesendet: Freitag, 15. August 2008 00:37 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] New 10mhz Distribution Amplifier > > > Additional specs to consider: > > The return loss should be low for 10 MHz and the first 8 > harmonics. The harmonic distortion should be low. The > isolation between outputs should be high. The phase drift vs > temperature should be low. The short term stability at 1 > second should be good. The magnetic field susceptibility > should be low. Line sidebands should be low. > > Compare, for example, the HP5087, a so-so design, to the > output amplifier design in the 5071A cesium, as documented > in my FCS paper in 1992. Huge difference in specs. The > 5071A has 120 dB isolation between outputs. > > Rick Karlquist N6RK > > > Bruce Griffiths wrote: > > Doug Millar wrote: > >> Hi, > >> A new 10mhz distribution amplifier is available at > amateur prices. > >> Jerry N7EME is producing them. His website is at > >> http://jwmeng.com/model_RDA-6.html > >> Doug K6JEY > >> > >> > >> > > There's a few specifications missing: > > > > 1) input impedance and return loss. > > > > 2) output impedance and return loss > > > > 3) phase noise > > > > These are essential if one is to make a rational decision on the > > suitability of the distribution amplifier. > > > > The outputs and inputs appear to share a common ground. > > This would preclude its use in some setups without external > means of > > providing the required isolation. > > > > The other question is does the device use AGC to set the > output level? > > If it does the phase noise floor will almost inevitably be > relatively > > high compared to the state of the art. > > > > 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 BNeubig at t-online.de Fri Aug 15 06:56:07 2008 From: BNeubig at t-online.de (BNeubig at t-online.de) Date: Fri, 15 Aug 2008 12:56:07 +0200 Subject: [time-nuts] =?iso-8859-15?q?New_10_MHz_Distribution_Amplifier?= In-Reply-To: <14E529E1B4BD4A9AB10351EE477743A3@MartynDesktop> References: <14E529E1B4BD4A9AB10351EE477743A3@MartynDesktop> Message-ID: <1KTwyV-21qtnM0@fwd33.aul.t-online.de> Hello Martyn, Martyn Smith wrote: Despite the AGC we still achieve good phase noise (-135 dBc/Hz @ 1 Hz with a -168 dBc noise floor) together with 130 dB isolation and 10 ps/C phase stability. I have problems to understand, how your amplifier can achieve phase noise of -135 dBc/Hz @ 1 Hz. Such a dBc/Hz measure is related to a carrier, but where does the carrier in your amp come from? The same applies to the graph in your data sheet. This obviously shows the phase noise of an oscillator, which feeds your distribution amplifier, not the inherent noise of the amplifier. It needs a different measurement technique to characterize the inherent noise of an amplifier, and there are different numbers to come out of that. At this point I am not able to argue about the -135 dBc/Hz @ 1 Hz for your OCXO, as you do not specify, what model and brand that is. Regards Bernd Neubig DK1AG __________________ AXTAL GmbH & Co.KG www.axtal.com From cupido at mail.ua.pt Fri Aug 15 07:33:47 2008 From: cupido at mail.ua.pt (Luis Cupido) Date: Fri, 15 Aug 2008 12:33:47 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A4E476.1060508@xtra.co.nz> References: <48A40F1C.4020800@mail.ua.pt> <48A4199C.5010109@xtra.co.nz> <48A4D3F1.3050007@mail.ua.pt> <48A4E039.1070900@xtra.co.nz> <48A4E476.1060508@xtra.co.nz> Message-ID: <48A5699B.4070303@mail.ua.pt> Bruce, John, ... And at smaller offsets like 100Hz and less ? Shouldn't the improvement be even bigger ? Closer to the carrier we are dealing with bigger signals so the ADC issues like resolution should be less important, and the limiting factor should really be the the phase noise of the LO's and etc. Am I right ? Luis Cupido. ct1dmk. Bruce Griffiths wrote: > Luis > > The R+S FMU36 has a phase noise floor of around -143dBc/Hz (offset > > 10kHz) with a 10MHz input. > Whereas the R+S FSU67 has a phase noise floor of around -133dBcdBc/Hz > (offset = 10kHz) with a 640Mhz input. > > There is a definite improvement at lower frequencies but not quite as > much as one might have expected. > > 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 jra at febo.com Fri Aug 15 08:17:40 2008 From: jra at febo.com (John Ackermann N8UR) Date: Fri, 15 Aug 2008 08:17:40 -0400 Subject: [time-nuts] thunderbolt for ntpd or gpsd In-Reply-To: <48A4E34E.5080700@intt.net> References: <200806151145.58089.w.knowles@xtra.co.nz> <48559045.4080703@stnhbr.com> <48A4E34E.5080700@intt.net> Message-ID: <48A573E4.4060101@febo.com> Yes, sadly this was a layout error that didn't get caught until too late (I'm still not sure why the rules check in the board layout software didn't catch it). Removing R4 if you're using DTR for power is the correct answer. John ---- Scott Mace wrote: > I found that on the two FatPPS units I have, pin 2 on the female DE-9 connector > is tied to the DC-IN. This was causing noise from the thunderbolt RS-232 > TX to get into the PPS output. It basically made it totally unusable. > I removed R4 since I use DTR for power and it works perfectly. > > Scott > > Tim Cwik wrote: >> Wayne Knowles wrote: >>> Tim, Chris, >>> >>> Over a month ago I experimented with getting GPSD and the Tunderbolt working >>> together. >>> I quickly added support for the missing TSIP packet types, and was able to get >>> xgps to display lat, long, time and constellation status. I did manage to >>> get NTP to work, have not invested the time into getting the 1PPS signal >>> working under FreeBSD yet. >>> >>> I have attached my patches against the gpsd source repository. Note that I >>> did not invest much time understanding the internals of gpsd beforehand so >>> some aspects may not be fully implemented. >>> >>> >> Thanks Wayne and Chris and Chris. >> >> I have discovered the even though cgps does not report position or time >> using the Thunderbolt, the stock gpsd is getting enough timing data to >> update ntp. Gpsd is selected as the sys.peer with a jitter of about .8. >> It looks like the PPS pulse is too narrow to be detected on DCD, I am >> going to investigate a pulse stretcher available from TAPR >> http://tapr.org/kits_fatpps.html and will see if that helps. FWIW, >> Centos 5.1 selinux allows gpsd to update the ntp shared memory segment >> out of the box. >> >> >> 73, >> >> >> _______________________________________________ >> time-nuts mailing list -- 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 Fri Aug 15 09:03:39 2008 From: jmiles at pop.net (John Miles) Date: Fri, 15 Aug 2008 06:03:39 -0700 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A5699B.4070303@mail.ua.pt> Message-ID: LO phase noise is almost always what limits the noise floor at close-in offsets, because of the narrow RBW (either analog or digital) typically used at those offsets to keep the carrier out of the measurement. Occasionally a high degree of RF attenuation might raise the equivalent front-end noise floor high enough to dominate the LO's inband noise, but that's not usually what happens. Certainly not if you're using a strong carrier to characterize the analyzer's PN floor. Phase noise at 100 Hz would likely be dominated by the reference, either the original 10 MHz reference or a higher-frequency crystal oscillator locked with a very low bandwidth. As in Bruce's example, if the first IF is 2 GHz and the LO is tuned to 3 GHz to receive a 1-GHz signal, there's a 50 dB penalty on a 10 MHz reference (20*log(3000/10)). A decent 10 MHz OCXO is good for about -150 dBc/Hz at 100 Hz from the carrier, so you would expect to see about -100 dBc/Hz at 100 Hz from the carrier on an analyzer built with this sort of architecture. That's a good match for what you see in the PSA data sheet, as well as the FSU67's. The 8560E portables are about 5 dBc/Hz worse. -- john, KE5FX > -----Original Message----- > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On > Behalf Of Luis Cupido > Sent: Friday, August 15, 2008 4:34 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Designing and building an OCXO and GPSDO > > > Bruce, > John, > .... > > And at smaller offsets like 100Hz and less ? > Shouldn't the improvement be even bigger ? > Closer to the carrier we are dealing with bigger signals > so the ADC issues like resolution should be less important, > and the limiting factor should really be the the > phase noise of the LO's and etc. > Am I right ? > > > Luis Cupido. > ct1dmk. > > > > Bruce Griffiths wrote: > > > Luis > > > > The R+S FMU36 has a phase noise floor of around -143dBc/Hz (offset > > > 10kHz) with a 10MHz input. > > Whereas the R+S FSU67 has a phase noise floor of around -133dBcdBc/Hz > > (offset = 10kHz) with a 640Mhz input. > > > > There is a definite improvement at lower frequencies but not quite as > > much as one might have expected. > > > > 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 bruce.griffiths at xtra.co.nz Fri Aug 15 09:28:44 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 16 Aug 2008 01:28:44 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A5699B.4070303@mail.ua.pt> References: <48A40F1C.4020800@mail.ua.pt> <48A4199C.5010109@xtra.co.nz> <48A4D3F1.3050007@mail.ua.pt> <48A4E039.1070900@xtra.co.nz> <48A4E476.1060508@xtra.co.nz> <48A5699B.4070303@mail.ua.pt> Message-ID: <48A5848C.80901@xtra.co.nz> Luis Cupido wrote: > Bruce, > John, > ... > > And at smaller offsets like 100Hz and less ? > Shouldn't the improvement be even bigger ? > Closer to the carrier we are dealing with bigger signals > so the ADC issues like resolution should be less important, > and the limiting factor should really be the the > phase noise of the LO's and etc. > Am I right ? > > > Luis Cupido. > ct1dmk. > Luis The R&S FSU67 has a phase noise of around -104dBc/Hz at 100Hz offset with a 640MHz input The R&S FMU36 has phase noise of around -115dBc/Hz at 100Hz offset with a 10MHz input. The limiting factor at low offsets is almost certainly due to local oscillator phase noise. Bruce From bruce.griffiths at xtra.co.nz Fri Aug 15 09:35:19 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 16 Aug 2008 01:35:19 +1200 Subject: [time-nuts] New 10 MHz Distribution Amplifier In-Reply-To: <14E529E1B4BD4A9AB10351EE477743A3@MartynDesktop> References: <14E529E1B4BD4A9AB10351EE477743A3@MartynDesktop> Message-ID: <48A58617.3050604@xtra.co.nz> Martyn Smith wrote: > I read with interest about the new 10 MHz distribution amplifier. > > But I agree with everyone, it's the specs that are missing that are > important. > > But I wanted to take one comment up about AGC. > > It depends how the AGC is done, there are some really poor examples for sale. > My company makes a nice distribution amplifier and we do have AGC. The nice > thing here is that a +7 dBm input (e.g PRS10 output) will give you up to +13 > dBm output. > > Despite the AGC we still achieve good phase noise (-135 dBc/Hz @ 1 Hz with > a -168 dBc noise floor) together with 130 dB isolation and 10 ps/C phase > stability. > > The phase noise at 1Hz offset is about 15dB or so higher than the state of the art. The effect of AGC should be most noticeable at low offsets. A phase tempco of 10ps/C is a bit for high precision work. > I suspect this low cost unit has a -140 or -150 dBc noise floor. > > But our unit costs a lot more than this low cost design, so maybe I'm not > being fair in comparing. > > www.ptsyst.com/DA1-100-10-B.pdf has all our specifications. > > I could probably talk our sales manager in a once off big discount for time > nuts readers, but I suspect it would still be out of the range of amateurs. > > Send me an email if you are interested (martyn at ptsyst.com) > > Martyn > Bruce From jim77742 at gmail.com Fri Aug 15 09:46:43 2008 From: jim77742 at gmail.com (Jim Palfreyman) Date: Fri, 15 Aug 2008 23:46:43 +1000 Subject: [time-nuts] Importing into EEC In-Reply-To: <48A54ED6.2050602@sonic.net> References: <63593424D48240B7ADB6FAED64ECD187@MartynDesktop> <48A54ED6.2050602@sonic.net> Message-ID: My pet hate is loose and lose. And there are many sufferers on this forum too... But no names! :-) Jim 2008/8/15 Rex > Martyn Smith wrote: > > I don't mean to knick pick, but ... > > > > I assume you didn't mean to nitpick either. > > Sorry. Not really important. I know it's bad form to criticize grammar > on the internet but it caught my attention. Don't get me started on > there, their and they're. > > > > _______________________________________________ > time-nuts mailing list -- 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 martyn at ptsyst.com Fri Aug 15 10:12:56 2008 From: martyn at ptsyst.com (Martyn Smith) Date: Fri, 15 Aug 2008 15:12:56 +0100 Subject: [time-nuts] CE Mark In-Reply-To: References: Message-ID: Sorry you are wrong. There is no exemtion for CE marking. Nothing is excempt. All test equipment, all electronic equipment, even "toothpaste" must be CE marked. There is no exemtion for personal use. You maybe are getting confused with RoHS where test equipment is exempt. Martyn From martyn at ptsyst.com Fri Aug 15 10:21:26 2008 From: martyn at ptsyst.com (Martyn Smith) Date: Fri, 15 Aug 2008 15:21:26 +0100 Subject: [time-nuts] Distribution Amplifier Phase Noise In-Reply-To: References: Message-ID: <9DAB23E903A947EA9F7F995879BC680B@MartynDesktop> Bernd, We in fact often make -140 dBc @ 1 Hz. However, our plots are of the amplifier only, not of any reference oscillator used. The measurement technique we use cancels out the inherent phase noise of the source used. The measurement technique takes a 10 MHz oscillator, splits it into two legs, phase shift one leg 90 degrees (quadature) and then measures the phase noise of the two legs. The phase noise of the source is cancelled out in this measurement technique. But remember, you do get oscillators that make -130 dBc/Hz at 1 Hz. Obviously it is essential for any distribution amplifier to be lower than the reference used. 10 dB is really the minimum margin that is needed. This can be very hard to achieve at times. We can achieve a floor noise of -172 dBc/Hz if we work hard at it. Regards Martyn From martyn at ptsyst.com Fri Aug 15 10:28:13 2008 From: martyn at ptsyst.com (Martyn Smith) Date: Fri, 15 Aug 2008 15:28:13 +0100 Subject: [time-nuts] Spellimng Mistakes In-Reply-To: References: Message-ID: Hi All, Yes I can't spell. I've just realised my spell checker isn't working. Not only can't I spell, I can't type!!! I did mean exemption if my previous email. Best Regards Martyn Best Regards From dave.g0dja at tiscali.co.uk Fri Aug 15 10:37:51 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Fri, 15 Aug 2008 15:37:51 +0100 Subject: [time-nuts] Importing into EEC In-Reply-To: References: <63593424D48240B7ADB6FAED64ECD187@MartynDesktop> <48A54ED6.2050602@sonic.net> Message-ID: <48A594BF.7060008@tiscali.co.uk> Jim Palfreyman wrote: > My pet hate is loose and lose. > Perhaps we could form a chapter of the AAAA? http://www.worldwidewords.org/articles/apostrophe.htm Dave (G0DJA) From rk at timing-consultants.com Fri Aug 15 11:45:24 2008 From: rk at timing-consultants.com (Rob Kimberley) Date: Fri, 15 Aug 2008 16:45:24 +0100 Subject: [time-nuts] Importing into EEC In-Reply-To: <2121.1218790159@critter.freebsd.dk> References: Your message of "Fri, 15 Aug 2008 09:44:58 +0100."<63593424D48240B7ADB6FAED64ECD187@MartynDesktop> <2121.1218790159@critter.freebsd.dk> Message-ID: <37C195870F1247CA91138B8A0326521E@Robin> It depends on local interpretations of the CE rules. UK as usual in all things emanating from the EU does it all to the letter, so yes, it is illegal here (may be a bit more relaxed up your way Poul, as common sense and EU don't seem to mix down here!). One can get exceptions in a few cases, especially if military customers are involved. But, the general rule is that if it hasn't got a CE mark in the UK you can't sell it. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Poul-Henning Kamp Sent: 15 August 2008 09:49 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Importing into EEC In message <63593424D48240B7ADB6FAED64ECD187 at MartynDesktop>, "Martyn Smith" wri tes: >Just wanted to remind everyone it's illegal to import any electronic >devices into Europe without them having a CE mark. That is not true. It is illegal to *sell* things without CE marks to the unwashed public, but you are allowed to import for personal use. In addition there are a vast array of exemptions, including professional test & measurement equipment. Furthermore, anything constructed before the CE mark requirement came into force in their local country are OK. >I see there have been many projects like the Jackson Labs unit that >have been imported into Europe. This is illegal. No, it is not, stop spreading FUD. 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. _______________________________________________ time-nuts mailing list -- 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 rexa at sonic.net Fri Aug 15 11:59:40 2008 From: rexa at sonic.net (Rex) Date: Fri, 15 Aug 2008 08:59:40 -0700 Subject: [time-nuts] Importing into EEC In-Reply-To: <48A594BF.7060008@tiscali.co.uk> References: <63593424D48240B7ADB6FAED64ECD187@MartynDesktop> <48A54ED6.2050602@sonic.net> <48A594BF.7060008@tiscali.co.uk> Message-ID: <48A5A7EC.1070803@sonic.net> Avian branch of the Apostrophe Police: http://www.xertech.net/pub/puncbird2.jpg -Rex David Ackrill wrote: > Jim Palfreyman wrote: > >> My pet hate is loose and lose. >> >> > > Perhaps we could form a chapter of the AAAA? > > http://www.worldwidewords.org/articles/apostrophe.htm > > Dave (G0DJA) > > _______________________________________________ > time-nuts mailing list -- 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 Fri Aug 15 12:16:34 2008 From: SAIDJACK at aol.com (SAIDJACK at aol.com) Date: Fri, 15 Aug 2008 12:16:34 EDT Subject: [time-nuts] CE Mark Message-ID: Hello Martyn, please keep in mind that CE marking is a self-certified mark. Not like the FCC marking, that has to be "officially" tested and certified by a big lab. I am sure a lot of products from Asia just have a label affixed to them, and never underwent any real testing. Also, most of the Jackson Labs products underwent CE testing and certification by several of our European resellers, and are so marked when sold under their private label, so they are electrically CE compliant. Bye, Said In a message dated 8/15/2008 07:14:01 Pacific Daylight Time, martyn at ptsyst.com writes: Sorry you are wrong. There is no exemtion for CE marking. Nothing is excempt. All test equipment, all electronic equipment, even "toothpaste" must be CE marked. There is no exemtion for personal use. You maybe are getting confused with RoHS where test equipment is exempt. Martyn **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-Volkswagen-Jetta-2009/expert-review?ncid=aolaut00030000000007 ) From mark.amos at toast.net Fri Aug 15 13:07:36 2008 From: mark.amos at toast.net (Mark Amos) Date: Fri, 15 Aug 2008 13:07:36 -0400 Subject: [time-nuts] Frequency distribution amp in Europe Message-ID: I'm not expert, but I suspect that this additional cost for electronic equipment could be one of the major contributing reasons that the time in some European countries can be up to 6 or even 8 hours off compared to "standard" North American time (EST.) I'm just sayin... Mark Message: 4 Date: Fri, 15 Aug 2008 09:44:58 +0100 From: "Martyn Smith" Subject: [time-nuts] Importing into EEC To: Message-ID: <63593424D48240B7ADB6FAED64ECD187 at MartynDesktop> Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Just wanted to remind everyone it's illegal to import any electronic devices into Europe without them having a CE mark. I see there have been many projects like the Jackson Labs unit that have been imported into Europe. This is illegal. I don't mean to knick pick, but it costs our company about $10000 to CE mark a product. And if we add one small option, it must be CE marked again. To the small manufacturer, this kills us and doesn't allow us to offer low prices. Steve Best Regards Martyn This Email is from: Martyn Smith Precision Test Systems LTD Tel: +44 (0) 1245 329608 Email: martyn at ptsyst.com Web: www.ptsyst.com NOTICE - This message contains legally privileged and confidential information intended only for the use of the addressee named above. If you are not the intended recipient of this message, you are hereby notified that you must not disseminate, distribute, copy or take any action in reliance on it. If you have received this message in error, please notify Precision Test Systems LTD. This communication represents the originator's personal views and opinions, which do not necessarily reflect those of Precision Test Systems Ltd. from whom it emanates. Further, Precision Test Systems Ltd. will not be held responsible for its contents and/or attachments, if the communication contravenes the rules of Precision Test Systems Ltd's email policy. From rk at timing-consultants.com Fri Aug 15 13:10:51 2008 From: rk at timing-consultants.com (Rob Kimberley) Date: Fri, 15 Aug 2008 18:10:51 +0100 Subject: [time-nuts] CE Mark In-Reply-To: References: Message-ID: CE testing/marking is a mine field. Not as simple a statement as self certifying! You need to tie in the CE certification with declarations of conformity (safety, EMC etc etc), all of which need testing. It's an expensive business. Rob Kimberley -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of SAIDJACK at aol.com Sent: 15 August 2008 17:17 To: time-nuts at febo.com Subject: Re: [time-nuts] CE Mark Hello Martyn, please keep in mind that CE marking is a self-certified mark. Not like the FCC marking, that has to be "officially" tested and certified by a big lab. I am sure a lot of products from Asia just have a label affixed to them, and never underwent any real testing. Also, most of the Jackson Labs products underwent CE testing and certification by several of our European resellers, and are so marked when sold under their private label, so they are electrically CE compliant. Bye, Said In a message dated 8/15/2008 07:14:01 Pacific Daylight Time, martyn at ptsyst.com writes: Sorry you are wrong. There is no exemtion for CE marking. Nothing is excempt. All test equipment, all electronic equipment, even "toothpaste" must be CE marked. There is no exemtion for personal use. You maybe are getting confused with RoHS where test equipment is exempt. Martyn **************Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos. (http://autos.aol.com/cars-Volkswagen-Jetta-2009/expert-review?ncid=aolaut00 030000000007 ) _______________________________________________ time-nuts mailing list -- 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 Fri Aug 15 14:12:16 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 18:12:16 +0000 Subject: [time-nuts] CE Mark In-Reply-To: Your message of "Fri, 15 Aug 2008 15:12:56 +0100." Message-ID: <1635.1218823936@critter.freebsd.dk> In message , "Martyn Smith" wri tes: >Sorry you are wrong. > >There is no exemtion for CE marking. Nothing is excempt. All test >equipment, all electronic equipment, even "toothpaste" must be CE marked. The CE rules only cover retail sale, it does not cover personal imports from non-CE countries, that would have been against WTO rules and caused an instant trade-war with both asia and USA. -- 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 Fri Aug 15 14:14:53 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 18:14:53 +0000 Subject: [time-nuts] CE Mark In-Reply-To: Your message of "Fri, 15 Aug 2008 18:10:51 +0100." Message-ID: <1689.1218824093@critter.freebsd.dk> In message , "Rob Kimberley" writes: >CE testing/marking is a mine field. Not as simple a statement as self >certifying! You need to tie in the CE certification with declarations of >conformity (safety, EMC etc etc), all of which need testing. No, you only need to tie them to measurements if you don't want to personally shoulder the blame if they are found to be non-conforming. -- 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 Arnold.Tibus at gmx.de Fri Aug 15 15:53:56 2008 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Fri, 15 Aug 2008 21:53:56 +0200 Subject: [time-nuts] CE Mark In-Reply-To: Message-ID: Hi to all, indeed, the CE-marking is quite complicated and sometimes a 'pain in the neck', but obviously necessary as well. I believe that all industrial manufactured products are affected, but I am not anymore in touch with these regulations. I found some pages with explanations and extracted some sentences for rough info, see yourself: from the European Parliament: http://www.europarl.europa.eu/news/expert/infopress_page/063-21952-049-02-08-911-20080221IPR21949-18-02-2008-2008-true/default_en.htm CE marking means a marking which materializes the declaration of the manufacturer that the product is in conformity with the applicable requirements set out in Community harmonization legislation providing for its affixing" says the committee in the agreement with the Council. Burden on importers In the agreement with the Council, the European Parliament underlines that importers must place only compliant products on the Community market. Before placing a product on the market importers must ensure that the appropriate conformity assessment procedure has been carried out by the manufacturer. They must ensure that the manufacturer has drawn up the technical documentation, that the product bears the required conformity marking(s), is accompanied by the required documents and that the manufacturer has respected the requirements set out in the directive. ... http://www.ce-marking.org/what-product.html Does my product need CE Marking? ... CE Marking is most probably required if you export to the 27 European Union (EU) and 3 European Free Trade Association (EFTA) member states the following 20 groups of products 3. # Low Voltage Electrical Equipment The "Electrical Equipment" means any equipment designed for use with a voltage rating of between 50 and 1000 V for alternating current (A.C.) and between 75 and 1500 V for direct current (D.C.). Therefore, it is called often "Low Voltage Electrical Equipment" which includes the vast majority of electrical equipment in everyday use. more >> 10. Measuring Instruments the "measuring instrument" means: any device or system with a measurement function that is covered by Articles 1 and 3; 15. Radio Equipment & Telecommunications Terminal Equipment (R&TTE) A "radio equipment" means a product, or relevant component thereof, capable of communication by means of the emission and/or reception of radio waves utilising the spectrum allocated to terrestrial/space radiocommunication. etc. http://www.ce-marking.org/93465eec+conformity+assessment+procedures+ce+marking+rules.html Annex, I. GENERAL GUIDELINES A. The principal guidelines for the use of conformity assessment procedures in technical harmonization directives are the following: (a) the essential objective of a conformity assessment procedure is to enable the public authorities to ensure that products placed on the market conform to the requirements as expressed in the provisions of the directives, in particular with regard to the health and safety of users and consumers; B. (b) The CE marking affixed to industrial products symbolizes the fact that the natural or legal person having affixed or been responsible for the affixing of the said marking has verified that the product conforms to all the Community total harmonization provisions which apply to it and has been the subject of the appropriate conformity evaluation procedures. 4. The CE marking must be affixed visibly, legibly and indelibly. (e) Any industrial product covered by the technical harmonization directives based on the principles of the global approach must bear the CE marking, save where the specific directives provide otherwise; such exceptions constitute derogations not from the marking requirement but from the administrative procedures for conformity evaluation, which may in certain cases be considered too cumbersome. Appropriate grounds must accordingly be given for any exception to or derogation from the marking requirement. The CE marking is the only marking which certifies that the industrial products conform to the directives based on the principles of the global approach. So far the not complete excerpts, good luck! Arnold, DK2WT ++++++++++++++++++++++++++++++++++++++++++++++++++++++ On Fri, 15 Aug 2008 18:10:51 +0100, Rob Kimberley wrote: >CE testing/marking is a mine field. Not as simple a statement as self >certifying! You need to tie in the CE certification with declarations of >conformity (safety, EMC etc etc), all of which need testing. >It's an expensive business. >Rob Kimberley >-----Original Message----- >From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On >Behalf Of SAIDJACK at aol.com >Sent: 15 August 2008 17:17 >To: time-nuts at febo.com >Subject: Re: [time-nuts] CE Mark >Hello Martyn, > >please keep in mind that CE marking is a self-certified mark. Not like the >FCC marking, that has to be "officially" tested and certified by a big lab. >I am sure a lot of products from Asia just have a label affixed to them, >and never underwent any real testing. > >Also, most of the Jackson Labs products underwent CE testing and >certification by several of our European resellers, and are so marked when >sold under their private label, so they are electrically CE compliant. > >Bye, >Said > > >In a message dated 8/15/2008 07:14:01 Pacific Daylight Time, >martyn at ptsyst.com writes: >Sorry you are wrong. >There is no exemtion for CE marking. Nothing is excempt. All test >equipment, all electronic equipment, even "toothpaste" must be CE marked. >There is no exemtion for personal use. >You maybe are getting confused with RoHS where test equipment is exempt. >Martyn >**************Looking for a car that's sporty, fun and fits in your budget? >Read reviews on AOL Autos. >(http://autos.aol.com/cars-Volkswagen-Jetta-2009/expert-review?ncid=aolaut00 >030000000007 ) _______________________________________________ >time-nuts mailing list -- 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 Fri Aug 15 16:06:21 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 20:06:21 +0000 Subject: [time-nuts] CE Mark In-Reply-To: Your message of "Fri, 15 Aug 2008 21:53:56 +0200." Message-ID: <2356.1218830781@critter.freebsd.dk> In message , "Arnold Tibus" writes: >I found some pages with explanations and extracted some sentences for rough >info, see yourself: And you caught the most important part: >Burden on importers > >In the agreement with the Council, the European Parliament underlines >that importers must place only compliant products on the Community >market. Before placing a product on the market importers must ensure >that [...] The important thing in this clause is "placing a product on the market". As long as you import things directly into EU, and never sell them again, there is no requirement for CE marking. 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 Arnold.Tibus at gmx.de Fri Aug 15 16:10:03 2008 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Fri, 15 Aug 2008 22:10:03 +0200 Subject: [time-nuts] CE Mark In-Reply-To: <1689.1218824093@critter.freebsd.dk> Message-ID: A summary somewhat easier to read you can find here: CE Marking: Your Passport to the European Union http://www.i-b-t.net/anm/templates/trade_article.asp?articleid=262&zoneid=3 perhaps it can bring some more light into the darkness of the worldtrade and the european market. regards Arnold, DK2WT From dforbes at dakotacom.net Fri Aug 15 16:10:52 2008 From: dforbes at dakotacom.net (David Forbes) Date: Fri, 15 Aug 2008 13:10:52 -0700 Subject: [time-nuts] CE Mark In-Reply-To: <2356.1218830781@critter.freebsd.dk> References: <2356.1218830781@critter.freebsd.dk> Message-ID: <48A5E2CC.9020602@dakotacom.net> Poul-Henning Kamp wrote: >> >> In the agreement with the Council, the European Parliament underlines >> that importers must place only compliant products on the Community >> market. Before placing a product on the market importers must ensure >> that [...] > > The important thing in this clause is "placing a product on the market". > > As long as you import things directly into EU, and never sell them > again, there is no requirement for CE marking. > Poul, This is interesting. It means that I, as an American exporter selling directly to end customers in the EU, do NOT need to CE mark my American made products. -- David Forbes, Tucson AZ, Estados Unidos Americanos From phk at phk.freebsd.dk Fri Aug 15 16:20:11 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 20:20:11 +0000 Subject: [time-nuts] CE Mark In-Reply-To: Your message of "Fri, 15 Aug 2008 13:10:52 MST." <48A5E2CC.9020602@dakotacom.net> Message-ID: <2688.1218831611@critter.freebsd.dk> In message <48A5E2CC.9020602 at dakotacom.net>, David Forbes writes: >Poul-Henning Kamp wrote: >>> >>> In the agreement with the Council, the European Parliament underlines >>> that importers must place only compliant products on the Community >>> market. Before placing a product on the market importers must ensure >>> that [...] >> >> The important thing in this clause is "placing a product on the market". >> >> As long as you import things directly into EU, and never sell them >> again, there is no requirement for CE marking. >> > >Poul, > >This is interesting. It means that I, as an American exporter selling directly >to end customers in the EU, do NOT need to CE mark my American made products. Correct, provided if you don't otherwise end up "placing the product on the market", ie: by advertising directly in the EU or in global media targeting EU audiences (ie: in native language). -- 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 dave.g0dja at tiscali.co.uk Fri Aug 15 16:32:50 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Fri, 15 Aug 2008 21:32:50 +0100 Subject: [time-nuts] CE Mark In-Reply-To: <48A5E2CC.9020602@dakotacom.net> References: <2356.1218830781@critter.freebsd.dk> <48A5E2CC.9020602@dakotacom.net> Message-ID: <48A5E7F2.50708@tiscali.co.uk> David Forbes wrote: > This is interesting. It means that I, as an American exporter selling directly > to end customers in the EU, do NOT need to CE mark my American made products. > I have bought several items from the US for personal use, and not for resale, I don't remember any of them having a CE mark and no one stopped me doing this. Now, this might be because the trade for persoan imports of small electronic items is not worth bothering about, or it could be that there's no legal obligation on me to ensure that what I buy has a CE mark... I also have a couple of Amateur bands handheld radios, bought second hand in the UK, that are from China and widely available to import through eBay. However, the UK Government is always keen to make sure I pay the various taxes levied on my purchases, so they must know that it is happening. Dave (G0DJA) From phk at phk.freebsd.dk Fri Aug 15 16:34:36 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 20:34:36 +0000 Subject: [time-nuts] CE Mark In-Reply-To: Your message of "Fri, 15 Aug 2008 22:10:03 +0200." Message-ID: <2770.1218832476@critter.freebsd.dk> In message , "Arnold Tibus" writes: >A summary somewhat easier to read you can find here: > >CE Marking: Your Passport to the European Union >http://www.i-b-t.net/anm/templates/trade_article.asp?articleid=262&zoneid=3 > >perhaps it can bring some more light into the darkness of the >worldtrade and the european market. HA! It doesn't even scratch the surface. First of all, that article incorporates, tacitly, US corporate legal liability thinking. Mostly, there are only two steps in the generic CE process: Sign a piece of paper that says that you put the CE mark there. Put the CE mark there. If your product does not live up to CE requirement, you have just made yourself the bulls-eye of the lawsuit or regulatory action. Obviously, anybody in a sane frame of mind would check that the requirements are met before doing that, but the law doesn't demand that you do so, it just assigns the liability. In select areas, where the danger to life and limb is greater than normal, cars, airbags and similar, there is a positive documentation requirement. As far as I know, no plain electrical gadget is under that regime, until voltages above 500V are exposed or radio transmission is involved. Once you get beyond electrical gadgets, it gets weirder. Take building materials: if they are CE marked, they can be sold anywhere in the EU, but that doesn't mean that you are actually allowed to build with them where you live. A window that complies with building codes in Greece fail northern energy-concious building codes. What Denmark consider a sound structual wall material would crumble in the first minor tremblor in Greece. You buy insulation materials from the northern end, and fumigate your house in the southern end ? You'd better not plan on moving back into the house because it will take years for the poison gas to be released again. They're talking about putting CE marks on foodstuffs also, but that is even more fraught with peril, because the "sell before date" is climate variant on a lot of foodstuffs. 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 dave.g0dja at tiscali.co.uk Fri Aug 15 16:38:21 2008 From: dave.g0dja at tiscali.co.uk (David Ackrill) Date: Fri, 15 Aug 2008 21:38:21 +0100 Subject: [time-nuts] CE Mark In-Reply-To: <2688.1218831611@critter.freebsd.dk> References: <2688.1218831611@critter.freebsd.dk> Message-ID: <48A5E93D.5030606@tiscali.co.uk> Poul-Henning Kamp wrote: > Correct, provided if you don't otherwise end up "placing the product > on the market", ie: by advertising directly in the EU or in global > media targeting EU audiences (ie: in native language). > That's interesting, given that it is often said that the UK and the US are two countries separated by a common language. What about if a non-EU company sponsors a website, hosted in Europe, and has their logo and products shown on the website, must their products be CE marked even if the end users import the units from the non-EU supplier? If so, that could impact on a lot of Amateur Radio, and other specialist interest, forums... Dave (G0DJA) From Arnold.Tibus at gmx.de Fri Aug 15 16:38:55 2008 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Fri, 15 Aug 2008 22:38:55 +0200 Subject: [time-nuts] CE Mark In-Reply-To: <2356.1218830781@critter.freebsd.dk> Message-ID: Poul-Henning, you are propably fully right! >And you caught the most important part: >>Burden on importers >> >>In the agreement with the Council, the European Parliament underlines >>that importers must place only compliant products on the Community >>market. Before placing a product on the market importers must ensure >>that [...] >The important thing in this clause is "placing a product on the market". >As long as you import things directly into EU, and never sell them >again, there is no requirement for CE marking. >Poul-Henning when reading this: [...] "For the purpose of law  all importers are treated as producers. (Ref article 3 council directive (85/374/EEC) [!!!] This is the reason that Importers in Europe are so much worried about CE Marking on the product they import because one failure of product in the market can ruin earnings of many years. " To safeguard their interest the importer needs CE marking from a notified body.Without CE Mark- complainant is awarded the damage and manufacturer is liable without limit. With CE Mark- the injured person shall be required to prove the damage, the defect and the causal relationship between defect and damage "[...] If I do import and not sell to others, I should have no problems, I am responsible for - myself (!), I am as importer the 'producer' (a.m.) for my own needs if I see it right. Nobody will ask (in case of single items or very small quantities for my own needs), but I may have problems to claim for something in case of trouble when the product is not safe... [...) "CONCLUSION: It is the sole responsibility of the Manufacturer/ Seller to identify the applicable Directives[...] http://ce-marking.blogspot.com/2008/07/your-liability-when-you-ce-mark-your.html regards, Arnold, DK2WT From phk at phk.freebsd.dk Fri Aug 15 16:51:10 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 20:51:10 +0000 Subject: [time-nuts] CE Mark In-Reply-To: Your message of "Fri, 15 Aug 2008 22:38:55 +0200." Message-ID: <2952.1218833470@critter.freebsd.dk> In message , "Arnold Tibus" writes: >Poul-Henning, >[...] "For the purpose of law all importers are treated as >producers. (Ref article 3 council directive (85/374/EEC) [!!!] > >This is the reason that Importers in Europe are so much worried >about CE Marking on the product they import because one failure of >product in the market can ruin earnings of many years. The point here is to get a local entity to sue, rather than some random chinese factory which have never existed once the mail arrives. Rumours have it, that the CE mark went through like lightning after a delegation from the EP/PE was taken through a Wall-Mart in the USA, and subsequently shown what the products contained and how they were constructed. I have not been able to verify this rumour. If you don't sell crap, you've got nothing to worry about. >If I do import and not sell to others, I should have no problems, I am >responsible for - myself (!), Exactly, as a group europeans are not known for suing themselves :-) But you could be held liable if your neighbor, child or spouse gets electrocuted, although they would probably use penal code rather than lack of CE mark in that case. 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 Fri Aug 15 16:57:18 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Fri, 15 Aug 2008 20:57:18 +0000 Subject: [time-nuts] CE Mark In-Reply-To: Your message of "Fri, 15 Aug 2008 21:38:21 +0100." <48A5E93D.5030606@tiscali.co.uk> Message-ID: <2982.1218833838@critter.freebsd.dk> In message <48A5E93D.5030606 at tiscali.co.uk>, David Ackrill writes: >Poul-Henning Kamp wrote: >> Correct, provided if you don't otherwise end up "placing the product >> on the market", ie: by advertising directly in the EU or in global >> media targeting EU audiences (ie: in native language). > >That's interesting, given that it is often said that the UK and the US >are two countries separated by a common language. I can warmly recommend "The midatlantic companion" by David Frost. >What about if a non-EU company sponsors a website, hosted in Europe, and >has their logo and products shown on the website, must their products be >CE marked even if the end users import the units from the non-EU supplier? Well, this is where you get to ask yourself if your lawyers are better than their laywers. As long as your product cannot kill anybody, the amount of liability you can have if you just slap a CE mark onto your product is limited, and that's all the testing what a lot of battery/low-voltage products go through. >If so, that could impact on a lot of Amateur Radio, and other specialist >interest, forums... I doubt it, proving that something is _not_ CE compliant is a pretty expensive process, and you can't sue somebody without evidence of wrongdoing. Just "supecting it is not CE compliant" will get you thrown out of a european court with a fine. So before anybody gets in trouble, somebody has to get hurt enough that tests are carried out. Most of the enforcement cases I have heard about have been form jealous competitors, which as I read it, also started this thread. 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 dibene at usa.net Fri Aug 15 16:59:19 2008 From: dibene at usa.net (Alberto di Bene) Date: Fri, 15 Aug 2008 22:59:19 +0200 Subject: [time-nuts] CE Mark In-Reply-To: References: Message-ID: <48A5EE27.6070503@usa.net> And beware from the CE Mark on goods coming from China.... What it does mean is just "China Export", and I am not kidding... 73 Alberto I2PHD From holrum at hotmail.com Fri Aug 15 17:06:34 2008 From: holrum at hotmail.com (Mark Sims) Date: Fri, 15 Aug 2008 21:06:34 +0000 Subject: [time-nuts] FTS-4060M/S24 finally says LOCKed In-Reply-To: References: Message-ID: Well, after a couple of months of continuous operation my 4060M cesium beam unit, it finally decided to say that it was LOCKed. It had been operating happily, but never said it was LOCKed. It appeared that the auto-ALIGN subroutine in the EPROM was corrupted because it would never do the control voltage sweep to find the correct resonance peak. It would turn of the MOD signal, then just sit there. You could align the unit manually and it was obviously locked (tracked GPSDO to within a few nanoseconds/day). Today, I walked in and found the green LOCK led had lit up. I checked all the monitor voltages and found that my quartz oven monitor level was now 3.6V like the manual says it should be. Previously it showed 5.0V (which I attributed to the fact that the OCXO was a FTS unit and not the usual Datum unit). I wonder what made it decide to start showing the proper OCXO oven monitor level? ---------------------------------------- _________________________________________________________________ Be the filmmaker you always wanted to be?learn how to burn a DVD with Windows?. http://clk.atdmt.com/MRT/go/108588797/direct/01/ From bruce.griffiths at xtra.co.nz Fri Aug 15 17:07:58 2008 From: bruce.griffiths at xtra.co.nz (Bruce Griffiths) Date: Sat, 16 Aug 2008 09:07:58 +1200 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A5699B.4070303@mail.ua.pt> References: <48A40F1C.4020800@mail.ua.pt> <48A4199C.5010109@xtra.co.nz> <48A4D3F1.3050007@mail.ua.pt> <48A4E039.1070900@xtra.co.nz> <48A4E476.1060508@xtra.co.nz> <48A5699B.4070303@mail.ua.pt> Message-ID: <48A5F02E.9090902@xtra.co.nz> Luis Cupido wrote: > Bruce, > John, > ... > > And at smaller offsets like 100Hz and less ? > Shouldn't the improvement be even bigger ? > Closer to the carrier we are dealing with bigger signals > so the ADC issues like resolution should be less important, > and the limiting factor should really be the the > phase noise of the LO's and etc. > Am I right ? > > > Luis Cupido. > ct1dmk. > > > > Luis The R&S FMU 36 is a baseband analyser employing a pair of 80MSPS ADCs so only the preamp, ADC, and 80MHz oscillator phase noise should be significant (assuming the calculation roundoff noise isnt a factor). Bruce From Arnold.Tibus at gmx.de Fri Aug 15 17:12:50 2008 From: Arnold.Tibus at gmx.de (Arnold Tibus) Date: Fri, 15 Aug 2008 23:12:50 +0200 Subject: [time-nuts] CE Mark In-Reply-To: <2952.1218833470@critter.freebsd.dk> Message-ID: On Fri, 15 Aug 2008 20:51:10 +0000, Poul-Henning Kamp wrote: >But you could be held liable if your neighbor, child or spouse gets >electrocuted, although they would probably use penal code rather >than lack of CE mark in that case. >Poul-Henning I am thinking exactly the same, perhaps this point was not expressed clear enough. I am always responsible affecting others somehow . Therefore specially radio amateurs have to pay attention when importing industrial manufactured rf-devices, radios etc. Because the 'long arm' of em-waves, neighbours and others are always somehow affected. That is why the EMC-regulations are more strict and without any 'humor', they must be fulfilled and what must be demonstrated in this case always by the producer/ importer! Therefore all products eg. from the well known transceiver manufacturer in Asia must have passed the necessary tests and show the CE mark as I am informed. regards Arnold, DK2WT From holrum at hotmail.com Fri Aug 15 17:36:18 2008 From: holrum at hotmail.com (Mark Sims) Date: Fri, 15 Aug 2008 21:36:18 +0000 Subject: [time-nuts] LPRO-101 internals In-Reply-To: References: Message-ID: Recently one of my LPRO-101 rubidium oscillators start acting flakey. First it started to not lock if it was powered up hot (like if switched off for a few seconds then switched back on). Next it started dropping out of lock while running. I replaced it with one of those $100 units from China (60 bucks if you by them by the bucket) which works just fine. So I decided to open up the flakey one and see if there was anything tweakable inside... well there is another pot, two variable caps, three variable inductors, and two select-to-test resistors. Oh yeah, not to mention 21 (yep, count 'em... 21) different two-pin jumper headers. And an 8 pin header mounted so it is accessible from the outisde world. And two other internal conenctor headers. Does anybody out there know what any of these goodies do? Does anybody know what tweakage might bring the flakey unit back to life if it starts acting up again? It saw that I was going to outsource its job to a cheap Chinese import and started working properly... ---------------------------------------- _________________________________________________________________ See what people are saying about Windows Live. Check out featured posts. http://www.windowslive.com/connect?ocid=TXT_TAGLM_WL_connect2_082008 From rvassar at rob-vassar.com Fri Aug 15 20:08:26 2008 From: rvassar at rob-vassar.com (Robert Vassar) Date: Fri, 15 Aug 2008 19:08:26 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <038e01c8fe81$d4a99920$04000100@didierhp> References: <48A2BEC0.50004@quackers.net> <48A2C43D.8080800@mail.ua.pt><48A2D924.3040809@hvsistemas.es> <038e01c8fe81$d4a99920$04000100@didierhp> Message-ID: Didier, "Goofy" is certainly an inappropriate engineering term. As I see it, the MCS-51 is ill suited to programming with a C compiler because of the small stack size and segmented RAM map. This makes writing an efficient code generator more difficult, and you have to keep certain limitations in mind while coding. These things don't make it impossible though, and I agree it's easier with SDCC than in pure ASM. Keil C is the benchmark by which all others are judged, but it costs several hundred $USD. The AVR has a nice flat memory map, plenty of registers, etc... It's just easier to write a compiler for. That isn't necessarily a benefit, as most of us are never going to write a compiler. The PIC... I have no nice words for the PIC. It's a CPU architecture kept alive by Donald Rumsfeld himself (He was the CEO of G.I. back in the '70's), and surely he must have made a deal with the Devil to make it as successful as it is. How's that for a religious argument? :-) Having said all that... Looking thru my parts box, I have ~20 MCS-51 variants, ranging from the original i80C31 that I learned on back in the mid-80's to a couple 89C450's and a AT89C51ED2 in 40 pdip that I wish I had a few more of. I have a couple Z80's, an 8085, 68000, 68020, none of which are particularly useful anymore. Then there's that one lone 16F84 PIC and it's programmer, which I think I used once. Cheers, Rob KC6OOM/5 On Aug 14, 2008, at 9:51 PM, Didier Juges wrote: > I am not sure what you mean about the 8051 being goofy to program > in C. > > Aside from the bit variable type, the Special Function Register > declarations > and the memory types (data, idata and xdata), which you only deal > with one > time (when declaring variables) and which you can even ignore in many > applications (the compiler can take care of it, as long as you are not > pushing the limits of the chip's capabilities), the code itself is > pure C. > > The 8051 is considerably easier to program in C than in assembly, > and there > are several very mature C compilers for the 8051. On the other > hand, the ACR > being supported by gcc certainly gives it an edge in that area. I > use SDCC > with the 8051, and it does a very good job. It is actively > developped and > maintained as a sourceforge project. > > I routinely compile and run my 8051 C code under gcc on the pc > because it's > easier to have multiple test cases to make sure the functions do > what I > think they do... All I need is a few declarations to resolve bit, > data, > idata and xdata and bingo. > > Didier KO4BB > >> -----Original Message----- >> From: time-nuts-bounces at febo.com >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Vassar >> Sent: Thursday, August 14, 2008 6:25 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] I want a good micro-controller >> >> >> >> >> Good grief! That's not a microcontroller! :-) >> >> >> >> I like the MCS-51 family, but they're kind of goofy to >> program in C, and 8-bit. Upside, lots of vendors & variants, >> including the really nice SiLabs mixed signal chips made here >> in Austin. AVR is much nicer to code in C, and has great >> tool support, but they're single source, and I have read that >> Atmel is not always completely forthcoming in their errata. >> >> >> Arm... If you need something that can run Linux.... But why >> not just go for a Soekris board at that point? :-) >> >> >> Rob >> KC6OOM/5 >> >> >> On Aug 13, 2008, at 7:06 PM, Bob Paddock wrote: >> >>>> any ARM7 outperforms the best PIC in price and performance :) >>> >>> http://beagleboard.org/ >>> >>> Get them from DigiKey, $149. >>> >>> http://dkc1.digikey.com/us/mkt/beagleboard.html >>> >>> "The USB-powered Beagle Board is a low-cost, fan-less single board >>> >>> computer utilizing Texas Instruments' OMAP3530 [ARM] application >>> processor >>> >>> that unleashes laptop-like performance and >>> >>> expansion without the bulk, expense, or noise of typical desktop >>> machines. >>> >>> Beagle Board is based on an OMAP3530 application processor >> featuring >>> an ARM(R) CortexT-A8 running at up to 600MHz and delivering >> over 1,200 >>> Dhrystone MIPS of performance via superscalar operation with highly >>> accurate branch prediction and 256KB of L2 cache. Focal to Beagle >>> Board experience is the high-speed USB 2.0 on-the-go (OTG) >> port that >>> can be utilized to provide power to the board or to deliver highly >>> flexible expansion. Standard PC peripherals can be connected to >>> Beagle Board using the USB with a mini-A to standard-A >> cable adapter, >>> DVI-D using an HDMI to DVI-D adapter, or through the MMC/SD/SDIO >>> connector enabling a complete desktop experience." >>> >>> >>> -- >>> http://www.wearablesmartsensors.com/ >>> http://www.softwaresafety.net/ >>> http://www.designer-iii.com/ >>> http://www.unusualresearch.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. >> > > > _______________________________________________ > time-nuts mailing list -- 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 Aug 15 21:30:25 2008 From: didier at cox.net (Didier Juges) Date: Fri, 15 Aug 2008 20:30:25 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: <48A2BEC0.50004@quackers.net><48A2C43D.8080800@mail.ua.pt><48A2D924.3040809@hvsistemas.es><038e01c8fe81$d4a99920$04000100@didierhp> Message-ID: <004601c8ff3f$a92fbe00$0a01a8c0@didierhp> Rob, I have been using the Keil compiler for work and home for about 15 years and only recently started using SDCC for home. They both do a fine job, even though SDCC still goes through some growing pains. I agree that having to keep track of data, idata and xdata is not a desirable feature by any stretch of the imagination, but with a little bit of discipline (and experience certainly does not hurt) you know what's critical and what's not, and unless you are trying to get the last microounce of performance or you are using a very small device, use the large memory model and fuget about it :-) Of course, if you take C code written for the PC (or for a multitasking OS) and try to run it as is on an 8051, you will quickly get out of stack and other resources, but no responsible coder would do that. One could argue that the lack of code migration to a 16 or 32 bit platform hurt the architecture, but it's only since we have started to put an ethernet interface and a TCP/IP stack that we have come close to the 64k limit (without code banking, which I would rather not have to do). I am debating at the moment if my next TCP/IP project will use the 8051 or if we will go to a 32 bit chip directly, and if so, the field is wide open. Code performance has not been an issue for me, and I suspect that with the 100 MIPs of the Silabs C8051F120, I won't get close to the limit any time soon. I started on the 8051 with the 87C552 15 years ago, but recently I kinda standardized on the Silabs familly. They have a good range, with excellent performance, good tools and good support, so at the moment (aside from the TCP/IP applications) I have no plan to switch. 73, Didier KO4BB > -----Original Message----- > From: time-nuts-bounces at febo.com > [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Vassar > Sent: Friday, August 15, 2008 7:08 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] I want a good micro-controller > > Didier, > > > "Goofy" is certainly an inappropriate engineering term. As I > see it, the MCS-51 is ill suited to programming with a C > compiler because of the small stack size and segmented RAM > map. This makes writing an efficient code generator more > difficult, and you have to keep certain limitations in mind > while coding. These things don't make it impossible though, > and I agree it's easier with SDCC than in pure ASM. Keil C > is the benchmark by which all others are judged, but it costs > several hundred $USD. > > The AVR has a nice flat memory map, plenty of registers, > etc... It's just easier to write a compiler for. That isn't > necessarily a benefit, as most of us are never going to write > a compiler. > > > The PIC... I have no nice words for the PIC. It's a CPU > architecture kept alive by Donald Rumsfeld himself (He was > the CEO of G.I. back in the '70's), and surely he must have > made a deal with the Devil to make it as successful as it is. > How's that for a religious argument? :-) > > > Having said all that... Looking thru my parts box, I have ~20 > MCS-51 variants, ranging from the original i80C31 that I > learned on back in the mid-80's to a couple 89C450's and a > AT89C51ED2 in 40 pdip that I wish I had a few more of. I > have a couple Z80's, an 8085, 68000, 68020, none of which are > particularly useful anymore. Then there's that one lone > 16F84 PIC and it's programmer, which I think I used once. > > > Cheers, > > Rob > KC6OOM/5 > > > On Aug 14, 2008, at 9:51 PM, Didier Juges wrote: > > > I am not sure what you mean about the 8051 being goofy to > program in > > C. > > > > Aside from the bit variable type, the Special Function Register > > declarations and the memory types (data, idata and xdata), > which you > > only deal with one time (when declaring variables) and > which you can > > even ignore in many applications (the compiler can take > care of it, as > > long as you are not pushing the limits of the chip's capabilities), > > the code itself is pure C. > > > > The 8051 is considerably easier to program in C than in > assembly, and > > there are several very mature C compilers for the 8051. On > the other > > hand, the ACR being supported by gcc certainly gives it an edge in > > that area. I use SDCC with the 8051, and it does a very > good job. It > > is actively developped and maintained as a sourceforge project. > > > > I routinely compile and run my 8051 C code under gcc on the > pc because > > it's easier to have multiple test cases to make sure the > functions do > > what I think they do... All I need is a few declarations to resolve > > bit, data, idata and xdata and bingo. > > > > Didier KO4BB > > > >> -----Original Message----- > >> From: time-nuts-bounces at febo.com > >> [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Vassar > >> Sent: Thursday, August 14, 2008 6:25 PM > >> To: Discussion of precise time and frequency measurement > >> Subject: Re: [time-nuts] I want a good micro-controller > >> > >> > >> > >> > >> Good grief! That's not a microcontroller! :-) > >> > >> > >> > >> I like the MCS-51 family, but they're kind of goofy to > program in C, > >> and 8-bit. Upside, lots of vendors & variants, including > the really > >> nice SiLabs mixed signal chips made here in Austin. AVR is much > >> nicer to code in C, and has great tool support, but they're single > >> source, and I have read that Atmel is not always completely > >> forthcoming in their errata. > >> > >> > >> Arm... If you need something that can run Linux.... But > why not just > >> go for a Soekris board at that point? :-) > >> > >> > >> Rob > >> KC6OOM/5 > >> > >> > >> On Aug 13, 2008, at 7:06 PM, Bob Paddock wrote: > >> > >>>> any ARM7 outperforms the best PIC in price and performance :) > >>> > >>> http://beagleboard.org/ > >>> > >>> Get them from DigiKey, $149. > >>> > >>> http://dkc1.digikey.com/us/mkt/beagleboard.html > >>> > >>> "The USB-powered Beagle Board is a low-cost, fan-less single board > >>> > >>> computer utilizing Texas Instruments' OMAP3530 [ARM] application > >>> processor > >>> > >>> that unleashes laptop-like performance and > >>> > >>> expansion without the bulk, expense, or noise of typical desktop > >>> machines. > >>> > >>> Beagle Board is based on an OMAP3530 application processor > >> featuring > >>> an ARM(R) CortexT-A8 running at up to 600MHz and delivering > >> over 1,200 > >>> Dhrystone MIPS of performance via superscalar operation > with highly > >>> accurate branch prediction and 256KB of L2 cache. Focal > to Beagle > >>> Board experience is the high-speed USB 2.0 on-the-go (OTG) > >> port that > >>> can be utilized to provide power to the board or to > deliver highly > >>> flexible expansion. Standard PC peripherals can be connected to > >>> Beagle Board using the USB with a mini-A to standard-A > >> cable adapter, > >>> DVI-D using an HDMI to DVI-D adapter, or through the MMC/SD/SDIO > >>> connector enabling a complete desktop experience." > >>> > >>> > >>> -- > >>> http://www.wearablesmartsensors.com/ > >>> http://www.softwaresafety.net/ > >>> http://www.designer-iii.com/ > >>> http://www.unusualresearch.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. > >> > > > > > > _______________________________________________ > > time-nuts mailing list -- 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 cfharris at erols.com Fri Aug 15 22:12:40 2008 From: cfharris at erols.com (Chuck Harris) Date: Fri, 15 Aug 2008 22:12:40 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: <48A2BEC0.50004@quackers.net> <48A2C43D.8080800@mail.ua.pt><48A2D924.3040809@hvsistemas.es> <038e01c8fe81$d4a99920$04000100@didierhp> Message-ID: <48A63798.50908@erols.com> Robert Vassar wrote: > > > The PIC... I have no nice words for the PIC. It's a CPU architecture > kept alive by Donald Rumsfeld himself (He was the CEO of G.I. back in > the '70's), and surely he must have made a deal with the Devil to > make it as successful as it is. How's that for a religious > argument? :-) > > > Having said all that... Looking thru my parts box, I have ~20 MCS-51 > variants, ranging from the original i80C31 that I learned on back in > the mid-80's to a couple 89C450's and a AT89C51ED2 in 40 pdip that I > wish I had a few more of. I have a couple Z80's, an 8085, 68000, > 68020, none of which are particularly useful anymore. Then there's > that one lone 16F84 PIC and it's programmer, which I think I used once. Oh good, they we can take your opinion on PIC's as that of an expert. -Chuck Harris From GandalfG8 at aol.com Sat Aug 16 06:28:58 2008 From: GandalfG8 at aol.com (GandalfG8 at aol.com) Date: Sat, 16 Aug 2008 06:28:58 EDT Subject: [time-nuts] I want a good micro-controller Message-ID: In a message dated 16/08/2008 01:11:09 GMT Daylight Time, rvassar at rob-vassar.com writes: The PIC... I have no nice words for the PIC. It's a CPU architecture kept alive by Donald Rumsfeld himself (He was the CEO of G.I. back in the '70's), and surely he must have made a deal with the Devil to make it as successful as it is. How's that for a religious argument? :-) ------------- LOL Keeping it secular, what's with the PIC bashing? Surely it's a case of horses for courses, and there's been enough successful commercial, as well as hobby, products based on PICs to suggest you might be just a wee bit out of touch with some parts of the real world:-) regards Nigel GM8PZR From iovane at inwind.it Sat Aug 16 07:15:08 2008 From: iovane at inwind.it (iovane at inwind.it) Date: Sat, 16 Aug 2008 13:15:08 +0200 Subject: [time-nuts] LPRO-101 internals Message-ID: I suggest not touching any of the adjustment points. Check the rb light. If it gets too reddish, then probably the lamp gets too hot. There is a resistor in the heater circuitry that may be faulty. I'm away at the moment, and don't have my notes on hand, but the resistor is on the bottom side of the board and has a value of 61900 Ohm (6192). Good luck. Antonio I8IOV > > Recently one of my LPRO-101 rubidium oscillators start acting flakey. First it started to not lock if it was powered up hot (like if switched off for a few seconds then switched back on). Next it started dropping out of lock while running. I replaced it with one of those $100 units from China (60 bucks if you by them by the bucket) which works just fine. > > So I decided to open up the flakey one and see if there was anything tweakable inside... well there is another pot, two variable caps, three variable inductors, and two select-to-test resistors. Oh yeah, not to mention 21 (yep, count 'em... 21) different two-pin jumper headers. And an 8 pin header mounted so it is accessible from the outisde world. And two other internal conenctor headers. > > Does anybody out there know what any of these goodies do? Does anybody know what tweakage might bring the flakey unit back to life if it starts acting up again? It saw that I was going to outsource its job to a cheap Chinese import and started working properly... > ---------------------------------------- > > _________________________________________________________________ > See what people are saying about Windows Live. Check out featured posts. > http://www.windowslive.com/connect?ocid=TXT_TAGLM_WL_connect2_082008 > _______________________________________________ > time-nuts mailing list -- 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 Aug 16 07:55:26 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 16 Aug 2008 13:55:26 +0200 Subject: [time-nuts] CE Mark In-Reply-To: <48A5E7F2.50708@tiscali.co.uk> References: <2356.1218830781@critter.freebsd.dk> <48A5E2CC.9020602@dakotacom.net> <48A5E7F2.50708@tiscali.co.uk> Message-ID: <48A6C02E.6000406@rubidium.dyndns.org> David Ackrill wrote: > David Forbes wrote: > >> This is interesting. It means that I, as an American exporter selling directly >> to end customers in the EU, do NOT need to CE mark my American made products. >> > > I have bought several items from the US for personal use, and not for > resale, I don't remember any of them having a CE mark and no one stopped > me doing this. > > Now, this might be because the trade for persoan imports of small > electronic items is not worth bothering about, or it could be that > there's no legal obligation on me to ensure that what I buy has a CE mark... > > I also have a couple of Amateur bands handheld radios, bought second > hand in the UK, that are from China and widely available to import > through eBay. > > However, the UK Government is always keen to make sure I pay the various > taxes levied on my purchases, so they must know that it is happening. The thing is, when you buy a non CE-marked product and things get out of hand. Like electrical safety or apparent violation of EMC rules or something, you and not the manufacture takes the blame. So you are interested in it even as a buyer. If it is reasnoble to assume it would conform, the risc is lower. For radio equipment, it needs to conform to the ETSI ENs as applicable, which are part of a CE mark. There has also surfaced a missconception about the testing aspect. For some equpment testing is required before putting the product on the market. For most others it is a thing which is wise to do before putting the product on the market. You really need to check the details for each product. For most of the equipment we discuss here, it is not required, but if you don't have it you don't know if you comply and you can be in big trouble, such as pulling the product of the market and stuff like that. Cheers, Magnus From magnus at rubidium.dyndns.org Sat Aug 16 08:02:49 2008 From: magnus at rubidium.dyndns.org (Magnus Danielson) Date: Sat, 16 Aug 2008 14:02:49 +0200 Subject: [time-nuts] CE Mark In-Reply-To: <48A5E93D.5030606@tiscali.co.uk> References: <2688.1218831611@critter.freebsd.dk> <48A5E93D.5030606@tiscali.co.uk> Message-ID: <48A6C1E9.70706@rubidium.dyndns.org> David Ackrill wrote: > Poul-Henning Kamp wrote: > >> Correct, provided if you don't otherwise end up "placing the product >> on the market", ie: by advertising directly in the EU or in global >> media targeting EU audiences (ie: in native language). >> > > That's interesting, given that it is often said that the UK and the US > are two countries separated by a common language. > > What about if a non-EU company sponsors a website, hosted in Europe, and > has their logo and products shown on the website, must their products be > CE marked even if the end users import the units from the non-EU supplier? > > If so, that could impact on a lot of Amateur Radio, and other specialist > interest, forums... It's part of marketing to EU customers, so... they are certainly in for CE marketing. Infact, one of their competitors could get them caugt in serious pain. So, yes. Cheers, Magnus From wje at quackers.net Sat Aug 16 08:36:05 2008 From: wje at quackers.net (wje) Date: Sat, 16 Aug 2008 08:36:05 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: <48A6C9B5.8040607@quackers.net> As the one who made the first comment about not liking the PIC, I'll give you my reasons. Yes, they are philosophical, even religious. I'm also distinguishing between microprocessors (this discussion) and other variants, such as DSPs, FPLDs, etc. First, I've used a very large number of different micros over the years for both 'real' work and my own purposes, starting with the Intel 8008 before it was commercially released. I've used Intel, TI, Motorola, Zilog, MOS Tech processors of multiple families, and yes, even PICs, all with wildly varying architectures. These days, given modern development tools, the architecture of a general-purpose micro really isn't particularly relevant. It's functionality and support tools that are important. Without a doubt, PIC made it possible for many hobbyists to put together nice projects that they would not necessarily have been able to do otherwise. My deep-seated revulsion comes from one source, and it's not the architecture, the company, or the capabilities of the chips. It's Basic, the language. Until relatively recently, PIC and Basic were almost synonymous, at least for the masses. I have both EE and CS degrees, and I work in both worlds. In my humble (but completely accurate and stable) opinion, Basic is not a programming language. It's a tool of Satan designed to convince people that they are programmers when they really should stick to their janitorial duties. This is a subset of the general problem that everyone thinks they are programmers, and usually think their code is perfect. But, that's a rant for a different audience. So, for me, given that there are some very good C development tools for mainstream processors, and frequently they are free, I just don't use PICs. As I mentioned earlier, I currently like the Motorola (I mean, Freescale; these silly name changes are yet another rant) MC68HCxx line; there's a wide choice of features and they can be flashed easily without a complicated programmer. The 8-pin xx908QT4 is a buck and does a fine job for many purposes, and most importantly, you can get a nice C development environment for the line, which was originally from CodeWarrior, for free. It also supports the entire line, from 8-bit to 32-bit, and with builtin support for all of the various on-chip 'peripherals'. Even now, I don't think Microchip provides a compiler that supports the low-end chips, but I haven't checked lately. But, when you get right down to it, you really need to pick the proper solution for your problem. If there was something the PICs provided that I couldn't get elsewhere, I'd use them. Religion is fine, but getting the job done is more important. BTW, for those that think you can't do anything with an 8-pin 8-bit micro, I did one design that supports an LCD, a rotary encoder, a Hall-effect sensor, and a button. At home, I use the same chip in every light switch in my house to implement a self-tuning capacitance sense switch. I even use a couple for a more time-nuts related tasks. One provides loop control for my GPS/Rb/Quartz standard, and one is used as a 555 timer replacement in my SmartClock->PC interface. (Ok, I was in a hurry, needed a pulse stretcher, and I didn't have any 555's lying around) Bill Ezell ---------- They said 'Windows or better' so I used Linux. GandalfG8 at aol.com wrote: > > In a message dated 16/08/2008 01:11:09 GMT Daylight Time, > rvassar at rob-vassar.com writes: > > The PIC... I have no nice words for the PIC. It's a CPU architecture > kept alive by Donald Rumsfeld himself (He was the CEO of G.I. back in > the '70's), and surely he must have made a deal with the Devil to > make it as successful as it is. How's that for a religious > argument? :-) > > > ------------- > LOL > > Keeping it secular, what's with the PIC bashing? > > Surely it's a case of horses for courses, and there's been enough successful > commercial, as well as hobby, products based on PICs to suggest you might be > just a wee bit out of touch with some parts of the real world:-) > > 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 rvassar at rob-vassar.com Sat Aug 16 09:44:50 2008 From: rvassar at rob-vassar.com (Robert Vassar) Date: Sat, 16 Aug 2008 08:44:50 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: <72894FB3-2532-4596-B050-869E8B872E41@rob-vassar.com> On Aug 16, 2008, at 5:28 AM, GandalfG8 at aol.com wrote: > > > Keeping it secular, what's with the PIC bashing? > > Surely it's a case of horses for courses, and there's been enough > successful > commercial, as well as hobby, products based on PICs to suggest > you might be > just a wee bit out of touch with some parts of the real world:-) > > regards > > Nigel > GM8PZR > > And: > Oh good, they we can take your opinion on PIC's as that of an expert. > > -Chuck Harris > Gentlemen, I could not have made that more tongue-in-cheek! It's a good thing this isn't about Python, the Amiga, or the obvious superiority of "vi", or I would have seen some real flames! My opinion on PIC's is no more valid than my opinion on brands of car. I can make some observations drawn from 20+ years of computing/ electronics hobby, and 15 years as a software professional. But I am not a professional embedded systems engineer. I can have entirely valid, well thought out reasons, but at the end of the day it's not much different than "I like VW, and I don't like Dodge". I can go fetch groceries with either one. To a professional, perhaps nothing of interest. To someone contemplating buying one of the "PIC'n" books or building any kind of programmer that involves two 9 volt batteries, perhaps they will find my comments a useful warning. As a member of the "brain damaged by Basic" generation, I mostly agree with Bill's comments regarding it's use. Yet I still keep the public domain 8052AH-BASIC image in my '51 code directory, and have fond memories of it's use. The PIC is not alone in propagating that mistake, though they seem to be the last. Cheers, Rob From jim77742 at gmail.com Sat Aug 16 10:03:44 2008 From: jim77742 at gmail.com (Jim Palfreyman) Date: Sun, 17 Aug 2008 00:03:44 +1000 Subject: [time-nuts] CE Mark In-Reply-To: <48A6C1E9.70706@rubidium.dyndns.org> References: <2688.1218831611@critter.freebsd.dk> <48A5E93D.5030606@tiscali.co.uk> <48A6C1E9.70706@rubidium.dyndns.org> Message-ID: Geez folks, You've all been caught by a Troll. What's this really got to do with time??? Someone in all the above said an importer is a producer. A producer can produce. It's when they sell, things get interesting. Likewise an importer can import. It's when they sell, things get interesting. As time-nuts with a weird hobby we can import or produce. It's when we sell, things get interesting. End of story. For those of you who are professionals and selling your product, I'm sure you've spoken to your lawyer. Can we drop it now? Please. The troll is laughing at us. Jim 2008/8/16 Magnus Danielson > David Ackrill wrote: > > Poul-Henning Kamp wrote: > > > >> Correct, provided if you don't otherwise end up "placing the product > >> on the market", ie: by advertising directly in the EU or in global > >> media targeting EU audiences (ie: in native language). > >> > > > > That's interesting, given that it is often said that the UK and the US > > are two countries separated by a common language. > > > > What about if a non-EU company sponsors a website, hosted in Europe, and > > has their logo and products shown on the website, must their products be > > CE marked even if the end users import the units from the non-EU > supplier? > > > > If so, that could impact on a lot of Amateur Radio, and other specialist > > interest, forums... > > It's part of marketing to EU customers, so... they are certainly in for > CE marketing. Infact, one of their competitors could get them caugt in > serious pain. > > So, yes. > > 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 phk at phk.freebsd.dk Sat Aug 16 10:20:36 2008 From: phk at phk.freebsd.dk (Poul-Henning Kamp) Date: Sat, 16 Aug 2008 14:20:36 +0000 Subject: [time-nuts] I want a good micro-controller In-Reply-To: Your message of "Sat, 16 Aug 2008 08:36:05 -0400." <48A6C9B5.8040607@quackers.net> Message-ID: <64367.1218896436@critter.freebsd.dk> Having spent 30 years programming things, let me just add this: The original PIC chips have a strange software architecture, but it uses very little silicon real-estate, which is why we suddenly could program things in DIP-8 format. If that is your business, they're not bad for the job. A good example of this kind of application is TVB's PPS divider in a PIC16F84 Once you get to program your stuff in 'C' or other high level languages you shouldn't need to bother with the software architecture, instead concentrate on what I/O, bootloading and what else is important. The fact that people program PIC's in BASIC is fine with me, in fact I think it has gotten a lot of people hooked on programming who would otherwise never have tried. If I started a project today, I would seriously consider ARM chips, which come from very small (LPC2103) and all the way up to what runs the iPhone and GCC has good arm support. Olimex.com (resold by sparkfun) has tons of different prototyping cards with all sorts of chips, browse around and find something you like. -- 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 newell at cei.net Sat Aug 16 10:37:21 2008 From: newell at cei.net (Scott Newell) Date: Sat, 16 Aug 2008 09:37:21 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A6C9B5.8040607@quackers.net> References: <48A6C9B5.8040607@quackers.net> Message-ID: <200808161437.m7GEbRaG006043@host22.the-web-host.com> At 07:36 AM 8/16/2008, wje wrote: >I have both EE and CS degrees, and I work in both worlds. In my humble >(but completely accurate and stable) opinion, Basic is not a programming >language. It's a tool of Satan designed to convince people that they are >programmers when they really should stick to their janitorial duties. >This is a subset of the general problem that everyone thinks they are >programmers, and usually think their code is perfect. But, that's a rant >for a different audience. So, how do you tell if you're not a programmer, but pretending to be one? My code is far from perfect, but it can usually be made to get the job done. I try not to cut too many corners, and the ones that I do cut bother me. But when you're the lone programmer on projects, it's hard to know if you're crummy or decent, since there's no one to measure against. (Of course, there's the metric of 'product shipped, product works, bossman happy, paycheck cashed', but that doesn't distinguish between good and bad programmers, just programmers that can fool others along with themselves.) -- newell N5TNL From t_list_1_only at braw.co.uk Sat Aug 16 10:46:42 2008 From: t_list_1_only at braw.co.uk (David ) Date: Sat, 16 Aug 2008 15:46:42 +0100 Subject: [time-nuts] NavSync CW12 and CW25 In-Reply-To: Message-ID: <000a01c8ffae$ea724990$0200a8c0@hp6110> (time-nuts Digest, Vol 49, Issue 14) Ed, a couple of rather delayed answers to your CW25 thoughts: > but if you changed the output frequency of the CW25 is it >possible that you might find a 'sweet spot' that would give > you a cleaner signal I've not experimented with that, it affects the simplicity of the synthesis design and it may not be that important. The PLL that locks the OCXO to the 'GPS' reference will have a very narrow bandwidth and operates a little like a LPF to minimize the transfer of 'GPS' phase noise sidebands & spurs to the OCXO. Finding a useful "sweet spot" frequency needs an appropriate way of dividing the OCXO down so the frequencies match in the PSD. In my system the initial loop is a 0.3 Hz bandwith, this is rather loose to get things going. It's now working and given some free time (Ha!) the loop bandwidth can probably come down by about a factor of 10, this may further clean the output signal. The most important consideration is what is happening very close to the carrier rather than noise and spurs much beyond 1kHz from carrier which will be heavily attenuated by the PLL. > Did you divide down the output from the CW12? Yes. I initially thought about a discrete system and did not quickly find the phase / frequency PSD I wanted (MC4044). I looked at modern monolithic synthesizers and was put off many due to the need for some form of controller to load and control them. I do have a bag of (long obsolete) PICs which I use for this sort of thing but additionally many of the modern monolithic synthesisers are not specified for frequencies as low as 10MHz although they may work well. About this time my raking through the recycling buckets found a few MC145152FN2 parts which are parallel load so just needed some hard wire links to set the signal and reference divider ratios, easy. The limitation in this application is that the reference divider is limited to ratios of 2^N, so in my toy N=7, the division is 128 in both paths. Contact me off list if you want one posted to you, I suspect they have been off the market for years. At the moment the OCXO is happily locking down and vastly cleaner than the CW25 output, given time I want to modify my 60kHz (MSF) time signal receiver before I review the PLL in the GPS. Regards David From holrum at hotmail.com Sat Aug 16 11:32:52 2008 From: holrum at hotmail.com (Mark Sims) Date: Sat, 16 Aug 2008 15:32:52 +0000 Subject: [time-nuts] LPRO-101 internals In-Reply-To: References: Message-ID: The rubidium lamp is glowing a nice violet color... does not seem to be any red. I need to compare it to one of the other units. If I start tweaking turny things, I would record the position of the device, turn it say 1/2 a turn and see if it made things better or worse. If better, we are done. If no change, return it to its original setting. If worse then turn it 1/2 turn the other direction. Those 21 internal jumpers seem to indicate that the unit is infinitely (OK, 2 millionly) configurable. It would be nice to know what those jumpers do. There has to be something useful there... One thing that I did not see was some kind of crystal... I assume it is either on the back of the board or in the lamp assembly (which gets rather hot for an OCXO oven). ---------------------------------------- _________________________________________________________________ Be the filmmaker you always wanted to be?learn how to burn a DVD with Windows?. http://clk.atdmt.com/MRT/go/108588797/direct/01/ From wje at quackers.net Sat Aug 16 12:10:18 2008 From: wje at quackers.net (wje) Date: Sat, 16 Aug 2008 12:10:18 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <200808161437.m7GEbRaG006043@host22.the-web-host.com> References: <48A6C9B5.8040607@quackers.net> <200808161437.m7GEbRaG006043@host22.the-web-host.com> Message-ID: <48A6FBEA.80907@quackers.net> You certainly don't need formal training to be a good programmer; I've seen plenty of code from CS grads that's terrible, and very nice code from art majors. In my book, a good program is one one that's organized logically, well documented, and performs the job it was designed to do. A god programmer is someone that produces such programs. That's it. The problem is that, with the advent PCs and easily-accessible programming tools, everyone thinks they can write code, and many can't. Then what you end up with is a tangled mess that's unmaintainable and indecipherable. It's interesting that any number of EE's will take great care in circuit design, but then throw together some poorly-designed code to run their beautiful circuit. But, this has been endemic in the hardware industry for as long as I've been around. Hardware companies frequently have the attitude that it's the hardware that's important and the software is just one of those minor bits that has to get tacked on. This was true even for some companies that should have known better; there were plenty of HW engineers I ran into back in the old Digital days that, even though they were building minicomputers, really considered software an unfortunate requirement that had to be shipped with their beautiful hardware. Ah well, this is really wandering off-topic and my blood pressure's going up. I think I'll go write some C code for an 8-bit micro to calm down. And yes, I use vi. :) Bill Ezell ---------- They said 'Windows or better' so I used Linux. Scott Newell wrote: At 07:36 AM 8/16/2008, wje wrote: I have both EE and CS degrees, and I work in both worlds. In my humble (but completely accurate and stable) opinion, Basic is not a programming language. It's a tool of Satan designed to convince people that they are programmers when they really should stick to their janitorial duties. This is a subset of the general problem that everyone thinks they are programmers, and usually think their code is perfect. But, that's a rant for a different audience. So, how do you tell if you're not a programmer, but pretending to be one? My code is far from perfect, but it can usually be made to get the job done. I try not to cut too many corners, and the ones that I do cut bother me. But when you're the lone programmer on projects, it's hard to know if you're crummy or decent, since there's no one to measure against. (Of course, there's the metric of 'product shipped, product works, bossman happy, paycheck cashed', but that doesn't distinguish between good and bad programmers, just programmers that can fool others along with themselves.) From bill at iaxs.net Sat Aug 16 14:06:26 2008 From: bill at iaxs.net (Bill Hawkins) Date: Sat, 16 Aug 2008 13:06:26 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A6FBEA.80907@quackers.net> References: <48A6C9B5.8040607@quackers.net><200808161437.m7GEbRaG006043@host22.the-web-host.com> <48A6FBEA.80907@quackers.net> Message-ID: <000001c8ffca$cd217de0$021ba8c0@cyrus> As long as we're off topic, but interesting - I was born in 1938. MIT had a 704 and punch cards and maybe FORTRAN in the fifties. A classmate wrote FORTH as a portable program for big telescopes. Programming tools have run off in different directions since then, just as today's tool section in a Big Box is very different from before the baby boom hit the market. Everybody that needs a tool has a good chance of finding what they're looking for, but they'll look for what they've used before or maybe a little better. Y'see, the human brain only weighs three pounds. It hasn't been possible to fit the sum of human knowledge into one brain for one or two hundred years, depending on the capability of the brain. So we have to specialize, and the specialties keep getting narrower. I helped design an industrial process control system in the eighties. One architect couldn't do it - it took one for hardware (Motorola 68K), one for programming (Unix), and one for process control (me, with 20 years of industrial control experience). It was a grand educational experience. So when someone says that this or that tool is absolutely useless, I take that as a sign of narrow specialization, in the dark about the rest of the world but egocentrically sure the rest of the world must be like them. It's a law of human nature, like "The prospect of wealth motivates deceit." Today's politicians seem unable to suppress that motivation. Veering back towards the list topic, I found this in "Four Laws that Drive the Universe" by Peter Atkins (it's about thermodynamics): "Energy is conserved because time is uniform: time flows steadily, it does not bunch up and run faster then spread out and run slowly. ... If time were to bunch up and spread out, then energy would not be conserved." But maybe uniform time is only a local effect, on the scale of the Universe. As far as we know, conservation of energy is not violated, so we have to find the causes of observed time variations in the hardware we've built or the programs we've written. Wait, what about Einstein's relativity? The flow of time is still uniform in a manner that can be predicted from the equations. Bill Hawkins -----Original Message----- From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of wje Sent: Saturday, August 16, 2008 11:10 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] I want a good micro-controller You certainly don't need formal training to be a good programmer; I've seen plenty of code from CS grads that's terrible, and very nice code from art majors. In my book, a good program is one one that's organized logically, well documented, and performs the job it was designed to do. A good programmer is someone that produces such programs. That's it. The problem is that, with the advent PCs and easily-accessible programming tools, everyone thinks they can write code, and many can't. Then what you end up with is a tangled mess that's unmaintainable and indecipherable. It's interesting that any number of EE's will take great care in circuit design, but then throw together some poorly-designed code to run their beautiful circuit. But, this has been endemic in the hardware industry for as long as I've been around. Hardware companies frequently have the attitude that it's the hardware that's important and the software is just one of those minor bits that has to get tacked on. This was true even for some companies that should have known better; there were plenty of HW engineers I ran into back in the old Digital days that, even though they were building minicomputers, really considered software an unfortunate requirement that had to be shipped with their beautiful hardware. Ah well, this is really wandering off-topic and my blood pressure's going up. I think I'll go write some C code for an 8-bit micro to calm down. And yes, I use vi. :) Bill Ezell ---------- They said 'Windows or better' so I used Linux. Scott Newell wrote: At 07:36 AM 8/16/2008, wje wrote: I have both EE and CS degrees, and I work in both worlds. In my humble (but completely accurate and stable) opinion, Basic is not a programming language. It's a tool of Satan designed to convince people that they are programmers when they really should stick to their janitorial duties. This is a subset of the general problem that everyone thinks they are programmers, and usually think their code is perfect. But, that's a rant for a different audience. So, how do you tell if you're not a programmer, but pretending to be one? My code is far from perfect, but it can usually be made to get the job done. I try not to cut too many corners, and the ones that I do cut bother me. But when you're the lone programmer on projects, it's hard to know if you're crummy or decent, since there's no one to measure against. (Of course, there's the metric of 'product shipped, product works, bossman happy, paycheck cashed', but that doesn't distinguish between good and bad programmers, just programmers that can fool others along with themselves.) _______________________________________________ time-nuts mailing list -- 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 Sat Aug 16 14:18:32 2008 From: rfnuts at arcor.de (Adrian) Date: Sat, 16 Aug 2008 20:18:32 +0200 Subject: [time-nuts] LPRO-101 internals In-Reply-To: References: Message-ID: <48A719F8.8050901@arcor.de> Mark, things wont get better by fooling around with the trimpots, IMO. Chances are some of the pots are quite sesitive, thus impossible to bring back to proper settings w/o detailed knowledge about the alignment procedure. I would refer to the LPRO manual that, unfortunately, doesn't contain detailed circuit and alignment information, but at least some basic functional diagrams. Then, put a manual from a well documented Rb (like the FRS) aside and try to re-engineer a detailed block diagram. This will show you how much it differs from the FRS, and what parts of the FRS manual are or aren't useful for your task. It should also show most of the functionality of the trim pots. That way, without having turned any pots, you'll have learned a lot about how the unit works, and that should be quite helpful for troubleshooting. Adrian Mark Sims schrieb: > The rubidium lamp is glowing a nice violet color... does not seem to be any red. I need to compare it to one of the other units. > > If I start tweaking turny things, I would record the position of the device, turn it say 1/2 a turn and see if it made things better or worse. If better, we are done. If no change, return it to its original setting. If worse then turn it 1/2 turn the other direction. > > Those 21 internal jumpers seem to indicate that the unit is infinitely (OK, 2 millionly) configurable. It would be nice to know what those jumpers do. There has to be something useful there... > > One thing that I did not see was some kind of crystal... I assume it is either on the back of the board or in the lamp assembly (which gets rather hot for an OCXO oven). > ---------------------------------------- > > _________________________________________________________________ > Be the filmmaker you always wanted to be?learn how to burn a DVD with Windows?. > http://clk.atdmt.com/MRT/go/108588797/direct/01/ > _______________________________________________ > time-nuts mailing list -- 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 Sat Aug 16 16:28:12 2008 From: cdelect at juno.com (corby d dawson) Date: Sat, 16 Aug 2008 13:28:12 -0700 Subject: [time-nuts] Oscillators on eBay Message-ID: <20080816.132813.-651453.3.cdelect@juno.com> Hi, I listed some frequency standard related items on eBay and will be listing some more in the next week or so. search items by seller corbymite Cheers! Corby Dawson ____________________________________________________________ Get credit card help today. Safe, fast, and easy. Click Now. http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3m2DVEnCitPqF2XZrte7CfOtBRWnkHUz5bpTMlZ9Gh8ofDPr/ From holrum at hotmail.com Sat Aug 16 17:12:18 2008 From: holrum at hotmail.com (Mark Sims) Date: Sat, 16 Aug 2008 21:12:18 +0000 Subject: [time-nuts] LPRO-101 internals In-Reply-To: References: Message-ID: I am already rather familiar with the workings of rubidium oscillators... I have built my own before (just for fun, using a salvaged physics package). The LPRO only has one adjustmnent pot (besides the frequency trim pot). All the other adjustments are trimmer caps and inductors. The first thing to try is that select-to-test resistor. Then the trim pot. If neither of those makes things better, I suspect that the inductors and capacitors will not help either. It is not worth spending more than a couple millichrons trying to reverse engineer the LPRO design when you can buy them for less than $100. I'd much rather just break out the diddle stick and start diddling the heck out of it... goes well my philosophy of "If it jams, force it. It it breaks, it needed fixing anyway." Only thing is the darn thing is working now. I guess the sight of my collection of diddle sticks and that 5 pound sledgehammer in the corner convinced it that it had better start behaving. ---------------------------------------- things wont get better by fooling around with the trimpots, IMO. Chances are some of the pots are quite sesitive, thus impossible to bring back to proper settings w/o detailed knowledge about the alignment procedure. I would refer to the LPRO manual that, unfortunately, doesn't contain detailed circuit and alignment information, but at least some basic functional diagrams. Then, put a manual from a well documented Rb (like the FRS) aside and try to re-engineer a detailed block diagram. This will show you how much it differs from the FRS, and what parts of the FRS manual are or aren't useful for your task. It should also show most of the functionality of the trim pots. That way, without having turned any pots, you'll have learned a lot about how the unit works, and that should be quite helpful for troubleshooting. _________________________________________________________________ Get ideas on sharing photos from people like you. Find new ways to share. http://www.windowslive.com/explore/photogallery/posts?ocid=TXT_TAGLM_WL_Photo_Gallery_082008 From didier at cox.net Sat Aug 16 19:00:17 2008 From: didier at cox.net (Didier Juges) Date: Sat, 16 Aug 2008 18:00:17 -0500 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A6FBEA.80907@quackers.net> References: <48A6C9B5.8040607@quackers.net><200808161437.m7GEbRaG006043@host22.the-web-host.com> <48A6FBEA.80907@quackers.net> Message-ID: <003401c8fff3$da43a060$0a01a8c0@didierhp> That is an interesting thread. So I feel like I have to add my $0.02 I am a casual programmer. I got into programming when I had to, because it was, at one time, the path of least resistance for something I wanted to do. I am otherwise an EE. Today, I spend my time 50/50 doing hardware design and software design. Most my software is embedded software, with a few exceptions. I am in the interesting position of having written (and re-written) essentially the same desktop application under 4 different environments: QuickBasic 4.5 (I can hear teeth clinching...), Microsoft QuickC 2.5 (MS-DOS), gcc under Linux and Visual Basic 6.0, so I think I can compare the environments and the results pretty well. While the visual appeal (eye candy) of the VB 6.0 version is undeniable, by far the easiest to maintain (and with fewest bugs) is the gcc version. Feature-wise, it matches the VB 6.0 version, but in different ways. It is not as pretty (ncurses on an 80x24 terminal is NOT eye-candy) but it does things that I have not even contemplated doing under VB. Basic (and Visual Basic) go out of their way to make things easy, and as a result allow way too many bugs (I call them undocumented features). They are great to quickly simulate a user interface, or for a quick tool, but you do not want to write large programs with it. Even though I know people who have done it successfully, I myself have not been successful with it. It is just too hard to do the right thing with Basic, it encourages slopiness. Other than the PC, I write a fair amount of code for the 8051 and it's variants, in C, using either the Keil compiler, or more recently the SDCC. I have done a good bit of assembly for the Motorola 68HC05 way back (and the 8008 even farther back), and I am very glad this is over. The Motorola architectures are usually pretty well done, but assembly? Pleeeeaaase... (actually not quite over yet, I have my version of the 10 MHz-PPS divider originally by TVB, mine runs on an 8051 and is written in assembly too) In general, I find C programs easy to write and easy to maintain, and C matches well with my hardware background. Didier KO4BB From dave.mallery at gmail.com Sat Aug 16 19:26:14 2008 From: dave.mallery at gmail.com (Dave Mallery) Date: Sat, 16 Aug 2008 17:26:14 -0600 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A6FBEA.80907@quackers.net> References: <48A6C9B5.8040607@quackers.net> <200808161437.m7GEbRaG006043@host22.the-web-host.com> <48A6FBEA.80907@quackers.net> Message-ID: <3010c9470808161626q389d5e24m4e933a66c83a6734@mail.gmail.com> bill but wasn't that hardware beautiful??? (gazes at 11/70 backplane on wall...) dave On Sat, Aug 16, 2008 at 10:10 AM, wje wrote: > You certainly don't need formal training to be a good programmer; I've > seen plenty of code from CS grads that's terrible, and very nice code > from art majors. > In my book, a good program is one one that's organized logically, well > documented, and performs the job it was designed to do. A god > programmer is someone that produces such programs. That's it. The > problem is that, with the advent PCs and easily-accessible programming > tools, everyone thinks they can write code, and many can't. Then what > you end up with is a tangled mess that's unmaintainable and > indecipherable. > It's interesting that any number of EE's will take great care in > circuit design, but then throw together some poorly-designed code to > run their beautiful circuit. But, this has been endemic in the hardware > industry for as long as I've been around. Hardware companies frequently > have the attitude that it's the hardware that's important and the > software is just one of those minor bits that has to get tacked on. > This was true even for some companies that should have known better; > there were plenty of HW engineers I ran into back in the old Digital > days that, even though they were building minicomputers, really > considered software an unfortunate requirement that had to be shipped > with their beautiful hardware. > Ah well, this is really wandering off-topic and my blood pressure's > going up. I think I'll go write some C code for an 8-bit micro to calm > down. And yes, I use vi. :) > Bill Ezell > ---------- > They said 'Windows or better' > so I used Linux. > > Scott Newell wrote: > > At 07:36 AM 8/16/2008, wje wrote: > > > > I have both EE and CS degrees, and I work in both worlds. In my humble > (but completely accurate and stable) opinion, Basic is not a programming > language. It's a tool of Satan designed to convince people that they are > programmers when they really should stick to their janitorial duties. > This is a subset of the general problem that everyone thinks they are > programmers, and usually think their code is perfect. But, that's a rant > for a different audience. > > > So, how do you tell if you're not a programmer, but pretending to be > one? My code is far from perfect, but it can usually be made to get > the job done. I try not to cut too many corners, and the ones that I > do cut bother me. But when you're the lone programmer on projects, > it's hard to know if you're crummy or decent, since there's no one to > measure against. (Of course, there's the metric of 'product shipped, > product works, bossman happy, paycheck cashed', but that doesn't > distinguish between good and bad programmers, just programmers that > can fool others along with themselves.) > > > > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Dave Mallery, K5EN (ubuntu linux 8.04) PO Box 3519; T or C, NM 87901 no gates... no windows! free at last! linux counter #64628 (since 1997) "People aren't as dumb as Microsoft needs them to be." --PJ, May 2007 From bruceraymond at ameritech.net Sat Aug 16 19:38:11 2008 From: bruceraymond at ameritech.net (Bruce Raymond) Date: Sat, 16 Aug 2008 19:38:11 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <003401c8fff3$da43a060$0a01a8c0@didierhp> References: <48A6C9B5.8040607@quackers.net><200808161437.m7GEbRaG006043@host22.the-web-host.com> <48A6FBEA.80907@quackers.net> <003401c8fff3$da43a060$0a01a8c0@didierhp> Message-ID: <48A764E3.9000801@ameritech.net> Hi all, I'm a lurker and decided to stick my neck out a little. I, too started out as a hardware engineer. In this case real hardware - I did structural analysis of nuclear components. That was a few lifetimes ago. I'm doing software now. I'm in agreement with the comments about Basic being conducive to sloppy programming. I want my compiler to do as much checking as possible, and that's not in line with Basic. I'm partial to C for embedded applications. The PIC architecture is truly atrocious. However, I've been using PICs for years and am familiar with the development environment. I'm not in a hurry to learn something else for casual use. The C compilers for PICs play games with creating a pseudo stack by reallocating memory. I'd hate to have to do that manually, but it seems to work alright when implemented by compiler. My actual contribution to the thread is a link to a free C compiler for PICs that works pretty well. I have been using the CCS compiler and switched to this one. www.sourceboost.com/ Bruce Raymond/ND8I Didier Juges wrote: > That is an interesting thread. So I feel like I have to add my $0.02 > > I am a casual programmer. I got into programming when I had to, because it > was, at one time, the path of least resistance for something I wanted to do. > I am otherwise an EE. Today, I spend my time 50/50 doing hardware design and > software design. Most my software is embedded software, with a few > exceptions. > > I am in the interesting position of having written (and re-written) > essentially the same desktop application under 4 different environments: > QuickBasic 4.5 (I can hear teeth clinching...), Microsoft QuickC 2.5 > (MS-DOS), gcc under Linux and Visual Basic 6.0, so I think I can compare the > environments and the results pretty well. > > While the visual appeal (eye candy) of the VB 6.0 version is undeniable, by > far the easiest to maintain (and with fewest bugs) is the gcc version. > Feature-wise, it matches the VB 6.0 version, but in different ways. It is > not as pretty (ncurses on an 80x24 terminal is NOT eye-candy) but it does > things that I have not even contemplated doing under VB. > > Basic (and Visual Basic) go out of their way to make things easy, and as a > result allow way too many bugs (I call them undocumented features). They are > great to quickly simulate a user interface, or for a quick tool, but you do > not want to write large programs with it. Even though I know people who have > done it successfully, I myself have not been successful with it. It is just > too hard to do the right thing with Basic, it encourages slopiness. > > Other than the PC, I write a fair amount of code for the 8051 and it's > variants, in C, using either the Keil compiler, or more recently the SDCC. I > have done a good bit of assembly for the Motorola 68HC05 way back (and the > 8008 even farther back), and I am very glad this is over. The Motorola > architectures are usually pretty well done, but assembly? Pleeeeaaase... > (actually not quite over yet, I have my version of the 10 MHz-PPS divider > originally by TVB, mine runs on an 8051 and is written in assembly too) > > In general, I find C programs easy to write and easy to maintain, and C > matches well with my hardware background. > > Didier KO4BB > > > _______________________________________________ > time-nuts mailing list -- 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 Sat Aug 16 21:15:38 2008 From: holrum at hotmail.com (Mark Sims) Date: Sun, 17 Aug 2008 01:15:38 +0000 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: Begin rant { I have been programming stuff since 1970 (IBM1130 in high school). I have programmed well over 100 different machines in far more than that many languages. You would be hard pressed to find a machine architecture/real lanuage that I have not used. I also have an EE degree and have designed several commercially available computers (and a couple of successful ones at that). I have done some pretty incredible things with PIC chips. I used them mainly because of their very predictable execution time per instruction. Apps included generating eight simultaneous channels of real time video syncs/time code overlays, a 3DES encrypted full duplex audio radio with 32 channels of PWM I/O and telemetry, the complete flight control system for an autonomous aircraft, etc. One application replaced over 100 TTL/PAL packages with a single 18 pin PIC. The TVB clock divider is a perfect application of a PIC progammed in assembly language (use the Parallax syntax, not that horrid Microchip babel). That said, PICs are a sorry, miserable excuse for a microprocessor. Paged memory is just so last millenium. It should have died an unlamented death in the 60's. Compilers and programmers waste a huge amount of time and CPU cycles fiddling with pages, etc. Same goes for the 8051's and their demon spawn. You can gussy up a toad with all the lipstick in the world, and it's still a toad. If you are going to program a micro in C, go with an AVR. They are not perfect, but at least they don't croak. End rant } ---------------------------------------- _________________________________________________________________ Get thousands of games on your PC, your mobile phone, and the web with Windows?. http://clk.atdmt.com/MRT/go/108588800/direct/01/ From cupido at mail.ua.pt Sat Aug 16 22:00:56 2008 From: cupido at mail.ua.pt (Luis Cupido) Date: Sun, 17 Aug 2008 03:00:56 +0100 Subject: [time-nuts] Designing and building an OCXO and GPSDO In-Reply-To: <48A5F02E.9090902@xtra.co.nz> References: <48A40F1C.4020800@mail.ua.pt> <48A4199C.5010109@xtra.co.nz> <48A4D3F1.3050007@mail.ua.pt> <48A4E039.1070900@xtra.co.nz> <48A4E476.1060508@xtra.co.nz> <48A5699B.4070303@mail.ua.pt> <48A5F02E.9090902@xtra.co.nz> Message-ID: <48A78658.8040704@mail.ua.pt> Bruce, John, Tks for all your comments about that topic. really interesting. Luis Cupido. ct1dmk. Bruce Griffiths wrote: > Luis Cupido wrote: >> Bruce, >> John, >> ... >> >> And at smaller offsets like 100Hz and less ? >> Shouldn't the improvement be even bigger ? >> Closer to the carrier we are dealing with bigger signals >> so the ADC issues like resolution should be less important, >> and the limiting factor should really be the the >> phase noise of the LO's and etc. >> Am I right ? >> >> >> Luis Cupido. >> ct1dmk. >> >> >> >> > Luis > > The R&S FMU 36 is a baseband analyser employing a pair of 80MSPS ADCs so > only the preamp, ADC, and 80MHz oscillator phase noise should be > significant (assuming the calculation roundoff noise isnt a factor). > > 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 wje at quackers.net Sat Aug 16 22:49:35 2008 From: wje at quackers.net (wje) Date: Sat, 16 Aug 2008 22:49:35 -0400 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <3010c9470808161626q389d5e24m4e933a66c83a6734@mail.gmail.com> References: <48A6C9B5.8040607@quackers.net> <200808161437.m7GEbRaG006043@host22.the-web-host.com> <48A6FBEA.80907@quackers.net> <3010c9470808161626q389d5e24m4e933a66c83a6734@mail.gmail.com> Message-ID: <48A791BF.6020004@quackers.net> Well, yes, it was. The first computer I actually owned was a PDP-8, essentially stolen in pieces from the DEC scrapyard. Core memory, who would have imagined that it would actually work? I mean, you could actually see the bits. And it had blinking lights, too. I still insist a computer isn't a real computer without blinking lights. Which leads to yet another little side diversion... there was some really fantastic hardware done back in the '70s and '80s, without the benefit of DSPs, FPGAs, or microprocessors that had more power than a modern wristwatch. I love reconditioning equipment from that era, and it's remarkable what could be done with a handful of discrete components that today is done with a million transistors worth of ICs. My oldest working device is a 5061A from '68, not counting useless things like my saturated-cell voltage standard; my favorite is a tie between my HP 5370A and my Solartron 7081 laboratory dvm. Another little gem (in my opinion at least) is the Polarad 632 spectrum analyzer. They're not exceptional by any modern measure, but they're dirt-cheap and do manage better than 120 db noise floor and a 10 Khz to 2 Ghz range. Plus, they have a nifty discrete IC digital video capture board that does scan storage, scan averaging, and peak detection, all without a single microprocessor in sight. Which reminds me, what happened to all that wonderful European engineering from companies like Datron and Solartron? Their equipment frequently beat the pants off of anything we were doing at that time (as I gaze lovingly at my pair of Datron 4910's). Bill Ezell ---------- They said 'Windows or better' so I used Linux. Dave Mallery wrote: bill but wasn't that hardware beautiful??? (gazes at 11/70 backplane on wall...) dave On Sat, Aug 16, 2008 at 10:10 AM, wje [1] wrote: You certainly don't need formal training to be a good programmer; I've seen plenty of code from CS grads that's terrible, and very nice code from art majors. In my book, a good program is one one that's organized logically, well documented, and performs the job it was designed to do. A god programmer is someone that produces such programs. That's it. The problem is that, with the advent PCs and easily-accessible programming tools, everyone thinks they can write code, and many can't. Then what you end up with is a tangled mess that's unmaintainable and indecipherable. It's interesting that any number of EE's will take great care in circuit design, but then throw together some poorly-designed code to run their beautiful circuit. But, this has been endemic in the hardware industry for as long as I've been around. Hardware companies frequently have the attitude that it's the hardware that's important and the software is just one of those minor bits that has to get tacked on. This was true even for some companies that should have known better; there were plenty of HW engineers I ran into back in the old Digital days that, even though they were building minicomputers, really considered software an unfortunate requirement that had to be shipped with their beautiful hardware. Ah well, this is really wandering off-topic and my blood pressure's going up. I think I'll go write some C code for an 8-bit micro to calm down. And yes, I use vi. :) Bill Ezell ---------- They said 'Windows or better' so I used Linux. Scott Newell wrote: At 07:36 AM 8/16/2008, wje wrote: I have both EE and CS degrees, and I work in both worlds. In my humble (but completely accurate and stable) opinion, Basic is not a programming language. It's a tool of Satan designed to convince people that they are programmers when they really should stick to their janitorial duties. This is a subset of the general problem that everyone thinks they are programmers, and usually think their code is perfect. But, that's a rant for a different audience. So, how do you tell if you're not a programmer, but pretending to be one? My code is far from perfect, but it can usually be made to get the job done. I try not to cut too many corners, and the ones that I do cut bother me. But when you're the lone programmer on projects, it's hard to know if you're crummy or decent, since there's no one to measure against. (Of course, there's the metric of 'product shipped, product works, bossman happy, paycheck cashed', but that doesn't distinguish between good and bad programmers, just programmers that can fool others along with themselves.) _______________________________________________ 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:wje at quackers.net 2. mailto:time-nuts at febo.com 3. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts From kg7tnt at msn.com Sat Aug 16 16:04:27 2008 From: kg7tnt at msn.com (Timothy Parham Sr) Date: Sat, 16 Aug 2008 20:04:27 -0000 Subject: [time-nuts] Nixie - tube clock - 16 Digit Readout ! Message-ID: Greetings to all , ! Happy to be added to the group : ) My finding a few nixies in a box that was given to me a few months ago has lead me to " here " * I have been on a quest to find the " RIGHT " nixie clock kit , whatever that really is --> I have done some thinking & now find myself wanting to colaborate with someone willing to tackle this project with me , In spite of my being an " EXTRA - CLASS - Opperator " = Ham call sign KG7TNT.... I have a limited ability to feel comfortable with reading scematics & translating that image to a PCB. I know that I can solder & recognise a power supply when I see it , I guess I'm just a bit overwhelmed with " where does it go to make it all work " ...... I'm mostly wanting to make a clock that shows the display as : 2008 * 12 * 31 * 59 * 59 *59 * 59 year * Month * Day * Hour * Minute * Second * 1/10 seconds .... And ! I found it only - fitting to have the background of this clock ; A movie poster of : THE - TIME - MACHINE ! I thank you all in advance for any &nd all help , I absolutely do appreciate it ; ) All for now , Tim From fortime at bellsouth.net Sun Aug 17 00:17:52 2008 From: fortime at bellsouth.net (phil) Date: Sun, 17 Aug 2008 00:17:52 -0400 Subject: [time-nuts] SatStat talk to 58534A ? Message-ID: <001301c90020$3814a3c0$a101a8c0@officemail> Does anyone know if the Symmetricom SatStat software (Version 5) will talk to a HP/Symmetricom 58534A I've been trying to no avail to get anything out of the 58534A I've been using a B&B Electronics RS422 to RS232 Converter. It locks, I have data on various pairs but trying to figure how to talk to it. I'm not 100 percent on pinouts but tried enough combinations that I should have hit on it ! Any help would be appreciated Thanks, Phil From holrum at hotmail.com Sun Aug 17 08:23:26 2008 From: holrum at hotmail.com (Mark Sims) Date: Sun, 17 Aug 2008 12:23:26 +0000 Subject: [time-nuts] I want a good micro-controller In-Reply-To: References: Message-ID: If you want beautiful hardware, there is absolutely nothing more beautiful than the HP9100A and HP-9100B calculators. Not an IC in them (OK a couple of op amps in the card reader), and VERY few transistors, very fast. Stroke CRT display, mag card reader, external data bus, core memory. Microcode was a 16 layer PCB where intersecting traces on different layers were the bits. Micro sequencer was a braid of memory cores. All the internal execution state was stored in mag cores. You could turn the thing off in mid cycle, throw in down a raging flooded river, retreive a year later, hose it off, turn it back on, and it would resume execution where it left off (this actually happened). See http://www.hpmuseum.org/hp9100.htm ---------------------------------------- _________________________________________________________________ Be the filmmaker you always wanted to be?learn how to burn a DVD with Windows?. http://clk.atdmt.com/MRT/go/108588797/direct/01/ From jherrero at hvsistemas.es Sun Aug 17 09:23:29 2008 From: jherrero at hvsistemas.es (Javier Herrero) Date: Sun, 17 Aug 2008 15:23:29 +0200 Subject: [time-nuts] I want a good micro-controller In-Reply-To: <48A791BF.6020004@quackers.net> References: <48A6C9B5.8040607@quackers.net> <200808161437.m7GEbRaG006043@host22.the-web-host.com> <48A6FBEA.80907@quackers.net> <3010c9470808161626q389d5e24m4e933a66c83a6734@mail.gmail.com> <48A791BF.6020004@quackers.net> Message-ID: <48A82651.40603@hvsistemas.es> > I still insist > a computer isn't a real computer without blinking lights. > So you will love the Thinking Machines CM computers... ;) 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 jherrero at hvsistemas.es Sun Aug 17 09:26:09 2008 From: jherrero at hvsistemas.es (Javier Herrero) Date: Sun, 17 Aug 2008 15:26:09 +0200 Subject: [time-nuts] Nixie - tube clock - 16 Digit Readout ! In-Reply-To: References: Message-ID: <48A826F1.8060206@hvsistemas.es> Ummm... I did not make it 2000-yr compliant... only 12 digits (yy mm dd hh mm ss) but GPS driven... http://www.hvsistemas.es/Imagenes/reloj.jpg Regards, Javier, EA1CRB Timothy Parham Sr escribi?: > Greetings to all , ! > > Happy to be added to the group : ) > > My finding a few nixies in a box that was given to me a few months ago has lead me to " here " * > > I have been on a quest to find the " RIGHT " nixie clock kit , whatever that really is --> > > I have done some thinking & now find myself wanting to colaborate with someone willing to > tackle this project with me , > In spite of my being an " EXTRA - CLASS - Opperator " = Ham call sign KG7TNT.... > I have a limited ability to feel comfortable with reading scematics & translating that image to a PCB. > I know that I can solder & recognise a power supply when I see it , > I guess I'm just a bit overwhelmed with " where does it go to make it all work " ...... > > I'm mostly wanting to make a clock that shows the display as : > > 2008 * 12 * 31 * 59 * 59 *59 * 59 > year * Month * Day * Hour * Minute * Second * 1/10 seconds > > .... And ! I found it only - fitting to have the background of this clock ; A movie poster of : > > THE - TIME - MACHINE ! > > I thank you all in advance for any &nd all help , I absolutely do appreciate it ; ) > > All for now , > Tim > _______________________________________________ > time-nuts mailing list -- time-nuts at febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ti