[time-nuts] Re: Spectracom 8143 GPS Disciplined Osc

[Bob Camp]

Hi

The 8195 dates back more than 20 years. That’s not to say the ones you have are > 20
years old, only that it is a possibility. The GPS system week roll over stuff is likely to impact
a device like this ( or has already ). It may manifest as the date simply being 1024 weeks off.
That may not matter at all in this application. I don’t know if the end user expects accurate
date information from the system.  If they do expect accurate date, the GPS module would 
need to be replaced with a newer one that has an identical command structure. 

Even if the end user isn’t running time and date from the unit, you likely will run into it as 
you fire them up and run through all the “does it lock ok” sort of tests. If it’s off, that’s expected. 
You just move on. 

Next up on a device like this is the OCXO. Again, it only *may* be 20+ years old. Regardless,
it’s worth checking the EFC voltage to make sure it’s still reasonably centered. If it’s off within 
20% of either limit, that should be addressed. The OCXO *might* have a mechanical tune ( I
doubt it) or it would need to be replaced. 

Final steps might involve checking the offset accuracy ( = are the internal synthesizers still
working ok? ) and the phase noise on the outputs.

Bob



> On Jan 13, 2023, at 6:47 PM, Shawn via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Hi Paul,
> 
> Yes, my mistake, It was the 8195 Oscillator with the 8143 switch.  I
> should've referred to the Oscillator number.
> 
> I'd like to re-ask the same re. the 8195.  These units have 10MHz with
> 1.544 and 1pps outputs.
> 
> -- 
> Sincerely,
> 
> Shawn Tayler
> 
> On Fri, 2023-01-13 at 10:43 -0500, paul swed via time-nuts wrote:
>> Shawn I don't think the 8143 is an oscillator or pair.
>> Its a master/backup switch and distribution amplifier.
>> Nice unit. One on the auction site with good pix.
>> Believe you should be able to find a manual on it.
>> Spectracom manuals had been available online. Maybe not anymore.
>> Good luck
>> Paul
>> WB8TSL
>> 
>> On Fri, Jan 13, 2023 at 10:05 AM Shawn via time-nuts <
>> time-nuts at lists.febo.com> wrote:
>> 
>>> Hey Guys,
>>> 
>>> I may have do a cleanup and refurb on some fairly old Spectracom
>>> 8143
>>> Disciplined Oscillators.  Are there some good resources and/or
>>> places
>>> to look for proper Care and Feeding type information?
>>> 
>>> They are being used in a communications system to synchronize
>>> Simulcast
>>> Communications as well as an older TDM style voice switch.  There
>>> are
>>> two in an A/B backup configuration.
>>> --
>>> Sincerely,
>>> 
>>> Shawn Tayler
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