[time-nuts] KS-24361 REF-0 standalone

D W watsondaniel3 at gmail.com
Sun Aug 9 11:26:24 EDT 2015


A quick update for everyone. I have successfully gotten a REF-0 to run standalone. I am using an AVR, an inexpensive GPS module and very minimal circuitry. The 'NO GPS' light is off, and SatStat shows it is locked and disciplining to the 1PPS.

The stability of this needs to be assessed for a day or two. But things are looking very good.

I plan to write up a complete procedure with code and pictures. I will post that here when I am done.

Thanks for all of your help Bob, and to the others that worked on the project.

Regards

Dan

> On Aug 8, 2015, at 7:40 PM, Bob Camp <kb8tq at n1k.org> wrote:
> 
> Hi
> 
> While the newer Oncore’s are technically backwards compatible 
> with the old units, in practice (as you have noted) that’s not a 100%
> sort of thing. If you work with a new(er) Oncore, you would pick different
> strings to use for this sort of thing. In order to have a “drop in” with an
> Oncore, you do indeed need a part made before (roughly) 2001. 
> 
> That kicks you back to  20 year old technology (the early Oncore silicon 
> came out in the mid 90’s) . A *lot* has happened in Moore’s Law terms since then. 
> A lot has also happened in “aggregate volume” (what ever you want to call 
> volume doubling) terms. Both of those things directly impact GPS receivers. 
> Top that off with SA going away after the early Oncore came out and you 
> have a LOT of changes. 
> 
> Is that all bad? Of course not. It’s what makes me focus more on the REF-0, with 
> a modern GPS than on the REF-1 with an old Oncore. You have the high stability /
> long loop stuff from the SA era. You have a high speed, high sensitivity GPS to
> go with it. In many ways, that’s the best of both worlds. 
> 
> ============
> 
> Hopefully somebody will pop up and take the gear off of your hands !!
> 
> Bob
> 
>> On Aug 8, 2015, at 1:59 PM, Bill Hawkins <bill at iaxs.net> wrote:
>> 
>> Bob Camp has done a fine job of explaining the recent Lucent hardware.
>> 
>> I have two of the old pairs with Rb oscillators and poor early Oncore
>> receivers. 
>> Then I got a new pair with crystals and better GPS. I got the idea to
>> use a new
>> crystal unit to pair with an old RB unit, so I did some research on the
>> messages
>> required to do that.
>> 
>> The data was acquired with a Pico Scope set to display the bytes as
>> ASCII
>> characters. The displays can be saved as text files, which can be edited
>> with
>> explanations of the data. I have no skills with microcomputers, and
>> after many
>> years working with computers have no desire to acquire them.
>> 
>> The messages decoded easily enough with the 1996 Oncore manual. The
>> problem
>> with mixing old and new units is that the old Oncore had six channels
>> while
>> the new one has eight. The messages don't match. The only difference is
>> two
>> more groups of satellite data.
>> 
>> I have text files (MS Word 2003) with the contents of the messages.
>> Considering
>> the low level of interest in this subject, please write to bill at iaxs.net
>> for 
>> further details. If you'd like to experiment with the hardware, please
>> make a
>> reasonable offer for any of it. The new units have been assembled with a
>> 28 volt
>> 3 amp supply into a mini-rack using aluminum angle. My time lab is being
>> downsized due to a move to senior living apartments. There's other
>> stuff.
>> 
>> Bill Hawkins
>> Bloomington, MN 55438
>> 
>> 
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob
>> Camp
>> Sent: Saturday, August 08, 2015 6:33 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] KS-24361 REF-0 standalone
>> 
>> Hi
>> 
>> As far as I know, the Symmetricom / HP designs that were done in the SA
>> era
>> (this is one of them) did not use the sawtooth correction information.
>> The signal
>> spreading (at the time they were designed) was just to great to make it
>> worth 
>> playing with. I have no authoritative source for that, but it does sound
>> reasonable. 
>> 
>> As with any “absolute” statement, there are sure to be exceptions 
>> ..
>> 
>> ======
>> 
>> For the strings, you need the right status bits in the right locations.
>> The KS
>> does not care that it always sees the same sat’s at the same locations
>> directly
>> over it’s own north pole location. It just wants data in the field. 
>> 
>> It does care about the TRAIM status and probably a few other bits here
>> and there.
>> None of them appear to be hard to guess. All of the specs for the Oncore
>> strings
>> are something Mr Google knows a lot about. 
>> 
>> If you do try to synthesize *real* strings off something like a uBlox,
>> remember that 
>> each of these guys had a slightly different idea about when the PPS
>> fired relative to 
>> things like correction data and the time label on that PPS. Getting the
>> time label wrong
>> is pretty easy to fix. I (unfortunately) have more than ample empirical
>> evidence of
>> what getting the sawtooth correction off one second does. It’s far
>> harder to track down
>> when only looking at the “outside” of the device.
>> 
>> Bob
>> 
>>> On Aug 7, 2015, at 8:18 PM, paul swed <paulswedb at gmail.com> wrote:
>>> 
>>> Dan exactly my thinking.
>>> I will guess it wants the string that says I have a 3d position lock.
>>> Something like @@ and 30-40 characters that would be fixed.I think
>> there is
>>> a CRC at the end. But all of the message can be copied from a real
>> oncore
>>> or simply monitor what comes out of the KS GPS unit. Hard to say whats
>>> needed but a good discussion. Be it any number of uProcs they can all
>>> easily do a fixed string.
>>> Regards
>>> Paul
>>> WB8TSL
>>> 
>>>> On Fri, Aug 7, 2015 at 5:13 PM, D W <watsondaniel3 at gmail.com> wrote:
>>>> 
>>>> Yes, I'm hoping that it just wants a dummy string to say GPS is ok,
>> and
>>>> doesn't actually use any information in it. If that's the case, code
>> can be
>>>> developed for PIC and AVR that will work for just about anyone, using
>> a ~$1
>>>> chip.
>>>> 
>>>> Even if the string does need to contain real GPS info, it should
>> still be
>>>> quite easy to do.
>>>> 
>>>> A while back I wrote some code to parse the serial string from a
>> Jupiter-T
>>>> and display the information on a 4 line LCD display. It worked very
>> nicely
>>>> but I never did anything useful with it. I think I'll take Bob's
>> notes and
>>>> incorporate the REF-0. That would make for a very compact setup.
>>>> 
>>>> Dan
>>>> 
>>>>> On Aug 7, 2015, at 2:06 PM, paul swed <paulswedb at gmail.com> wrote:
>>>>> 
>>>>> Looking forward to the notes.
>>>>> Yes it could be fairly simple if what ref 0 wants is a string that
>>>>> essentially says the system is fixed with 3 d accuracy. Perhaps
>> after
>>>> that
>>>>> the ref 0 makes no checks other then the string keeps coming with
>> the
>>>>> correct quality. Not to push a particular proc but any of the low
>> end
>>>> ones
>>>>> will do that stunt very easily.
>>>>> That would be pretty sweet.
>>>>> Paul
>>>>> WB8TSL
>>>>> 
>>>>>> On Fri, Aug 7, 2015 at 10:13 AM, Bob Camp <kb8tq at n1k.org> wrote:
>>>>>> 
>>>>>> Hi
>>>>>> 
>>>>>> Ok, I will write something up and post it here. It will probably
>> take a
>>>>>> few days
>>>>>> to get it all into a form that answers most of the questions.
>>>>>> 
>>>>>> What you will need:
>>>>>> 
>>>>>> 1) A working REF-0
>>>>>> 2) A PIC or other micro to get things going
>>>>>> 3) A GPS with a PPS output (any will do)
>>>>>> 4) Code specific to your GPS and the needs of the REF-0
>>>>>> 
>>>>>> Since the Oncore needs to be set up each time it’s booted, there is
>> no
>>>> real
>>>>>> advantage to using one. You still need an MCU in the mix.
>>>>>> 
>>>>>> More to follow.
>>>>>> 
>>>>>> Bob
>>>>>> 
>>>>>>> On Aug 7, 2015, at 5:24 AM, Graham <planophore at aei.ca> wrote:
>>>>>>> 
>>>>>>> Bob,
>>>>>>> 
>>>>>>> I would like that information too please and thank you.
>>>>>>> 
>>>>>>> I have a pair that is working quite well and I also have a second
>> REF-0
>>>>>> that I want to start testing but just haven't got round to it yet
>> to
>>>> figure
>>>>>> out what is needed.
>>>>>>> 
>>>>>>> cheers, Graham ve3gtc
>>>>>>> 
>>>>>>> 
>>>>>>>> On 2015-08-07 02:39, Bob Camp wrote:
>>>>>>>> Hi
>>>>>>>> 
>>>>>>>> You need to get the Oncore running with the correct position
>> locked in
>>>>>> and spitting out the right strings.
>>>>>>>> That’s all done by the CPU in the REF-1 unit. The REF-0 simply
>> grabs
>>>>>> the data off of the string
>>>>>>>> as it comes by.
>>>>>>>> 
>>>>>>>> I’ll see if I can dig out the information and send it to you off
>> list.
>>>>>> It’s buried around here somewhere.
>>>>>>>> 
>>>>>>>> Bob
>>>>>>>> 
>>>>>>>>> On Aug 6, 2015, at 10:02 PM, Edesio Costa e Silva <
>>>>>> time-nuts at tardis.net.br> wrote:
>>>>>>>>> 
>>>>>>>>> Thanks.
>>>>>>>>> 
>>>>>>>>> I have some Motorola Oncore available.
>>>>>>>>> 
>>>>>>>>> Can you detail this "fairly simple manipulation of the signal
>> lines"?
>>>>>>>>> 
>>>>>>>>> Regards,
>>>>>>>>> 
>>>>>>>>> Edésio
>>>>>>>>> 
>>>>>>>>>> On Thu, Aug 06, 2015 at 09:57:20PM -0400, Bob Camp wrote:
>>>>>>>>>> Hi
>>>>>>>>>> 
>>>>>>>>>> People got a bit ???excited??? about the level of KS box
>>>> discussions.
>>>>>> All of the work decoding
>>>>>>>>>> the 15 pin connector and how to drive the REF-0 was taken off
>> list.
>>>>>>>>>> 
>>>>>>>>>> Simple answer:
>>>>>>>>>> 
>>>>>>>>>> Yes you can run a REF-0 by it???s self. It needs a dummy string
>> that
>>>>>> looks like the output
>>>>>>>>>> of a Motorola Oncore to feed it and some fairly simple
>> manipulation
>>>>>> of the signal lines.
>>>>>>>>>> It will then quite happily discipline to the pps you feed it.
>>>>>>>>>> 
>>>>>>>>>> Bob
>>>>>>>>>> 
>>>>>>>>>>> On Aug 6, 2015, at 7:27 PM, Edesio Costa e Silva <
>>>>>> time-nuts at tardis.net.br> wrote:
>>>>>>>>>>> 
>>>>>>>>>>> Hello Fellows!
>>>>>>>>>>> 
>>>>>>>>>>> Had anyone managed to run the KS-24361 REF-0, the one without
>> GPS,
>>>>>> as a
>>>>>>>>>>> standalone unit? If so, can you provide some links on how to
>>>>>> configure it?
>>>>>>>>>>> 
>>>>>>>>>>> The reason to try this is cost. The REF-0 unit costs USD 25 +
>> USD
>>>>>> 52.30
>>>>>>>>>>> (shipping to Brazil) and I have to pay the same amount as
>> custom
>>>>>> taxes.
>>>>>>>>>>> 
>>>>>>>>>>> Right now the REF-0/REF-1 pair would be too expensive.
>>>>>>>>>>> 
>>>>>>>>>>> Regards,
>>>>>>>>>>> 
>>>>>>>>>>> Edésio
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