[time-nuts] thunderbolts not seeing satellites

[bg at lysator.liu.se]

Hi Jamie,

Your setup looks fine. Is this your Lucent antenna?

    http://picasaweb.google.com/nhbbobb/20091115

It has less gain - some 10dB - than the HP/Agilent/Symmetricom branded
58532A. But the Lucent should work with the good coax and short cables
your setup has.

   http://www.symmetricom.com/media/files/downloads/product-datasheets/ds-58532a.pdf

I have run Tbolts behind 4 and 8-port L1-splitters (58536A and 58517A) as
well as 2 and 4 ports L1/L2 splitters from GPS networking with no problem.

What kind of GPS is the still working receiver you have? What kind of SNR
does it see for high elevation satellites? Is this the same as previously
when the Tbolts were still working?

While its unlikely, good antennas has broken down gradualy in the past.
Sometimes birds "helps" the outside weather gods getting a little crack to
let moisture inside the antenna.

Do you have another antenna to test with?

Good luck!

--

   Björn

> Hello everyone! Hope your new year is going well so far.
>
> I have two Tbolts (one from TAPR and one from another guy), and neither
> one is locking on satellites.
>
> My set up is a Lucent antenna, about 12 feet of LMR400, a Symmetricom 4
> way Active "SmartSplitter",  then about 3 feet of LMR 195 to my non-TAPR
> Tbolt.  I have another GPS (non Tbolt) on the SmartSplitter also (that
> works fine, ie: is RX satellites).  This set up has worked for a couple
> years.
>
> I originally powered my non-TAPR Tbolt with three "wall warts".  When I
> got this GPS, I was told it took non-standard power of +12/+5/-7.
>
> A while ago I noticed my Tbolt stopped working.  I took it offline and
> replaced it with one I bought from TAPR a year previous.  Additionally, I
> powered my "new" Tbolt with an HP 6236B, and everything worked fine.
>
> Now, this morning I noticed my Tbolt is not working again!
>
> It powers up, draws expected current on start up (then backs down after
> oven warms up) and I can monitor it with tboltmon.exe.
>
> I did a factory reset then manually input my position.
>
> No critical alarms are showing (all green) and minor alarms are all green
> except for: Satellite Tracking, Oscillator Disciplining, and Almanac,
> which are yellow.
>
> I have all 0.0 AMUs under Signal Levels.
>
> I think because the other GPS (non-Tbolt) works, my antenna and splitter
> is fine.
>
> I have also tried switching ports on the splitter.
>
> I have tested my jumper cable for shorts and continuity.
>
> Interestingly enough, if I power my original Tbolt (the +12/+5/-7 one)
> from the wall warts, it will "see" 2 satellites, but with very poor signal
> strength.  It will not see anything powered with +12/+5/-12 from the HP
> PS.
>
> Both Tbolts have the same symptoms.
>
> Anyone ever see issues like this?  Or have any suggestions?
>
> Jamie
>
>
>
>
>
>
>
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