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

[JC]

No problem, Shawn, and thanks to Davem for the complete manual. I don't
know why I didn't download it when it was available.

John



On Sat, Jan 14, 2023 at 10:47 AM paul swed via time-nuts <
time-nuts at lists.febo.com> wrote:

> I did download the manual and good news according to it there are 5 X 10
> MHz outputs on the back.
> Now thats useful. The telco stuff is derived from the 10 MHz. Not useful.
> No schematics. This must have been near the end when they were no longer
> included.
>
> XXX If you do not have the spectracom antenna, measure the center pin to
> ground. Without any antenna.
> Way back when that could be 12-15V. Especially if the antenna had a down
> converter in it. Do not believe these did.
> Modern antennas are 3.3 or 5V. Don't want to let the smoke out.
> XXX
>
> Good luck. Are you going to fire them up?
> Regards
> Paul
> WB8TSL
>
> On Sat, Jan 14, 2023 at 11:31 AM Bob Camp via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
> > 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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> > >>>
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