Hi
If the OCXO only makes it 6x10^-10 past 10 MHz, that’s not enough for the unit
to lock properly. 40 Hz tune range looks fine so not a shorted tune line. New
best
guess would still be an OCXO problem. Swap it out and see what happens. The
OCXO’s show up on eBay all the time. Who knows what
Hi
If your OCXO tunes to 10 MHz at -3.5V and it used to tune at +0.5V, it sounds
like the tune line is shorted somewhere.
That could be inside the OCXO or outside. If the short is “noisy” (and that is
not unusual) you aren’t going to get it to lock.
You need to figure out where the short is.
It looks like since last Oct the osc jumped frequency and has become less
stable.
This is not unheard of for an ocxo. It may be time to replace with a true
Trimble Thunderbolt. A couple are now on ebay for 2-300$. It is possible to
replace the ocxo, assuming nothing else is wrong with the
Hi All,
Sorry I forgot to attach the freq vs DAC voltage table to the email that
I just sent:
DAC V Freq
+5.0 9.999.961
+0.0 9.999.985
-3.0 9.999.998
-3.5 10.000.000
-3.8 10.000.001
-4.0 10.000.002
-4.5 10.000.004
-5.0 10.000.006
So the oscillator is not
Hi Nigel, and Bob, and Bill!
Thanks for the notes! I very much appreciate your helpful comments. I
will give my responses to all of your helpful posts here. Sorry for the
delay in responses. The reason for the delay is that my Thunderbolt is
at a remote site and I can communicate with it
Hi
The steering on the TBolt comes from code phase measurements on the
incoming GPS signals. The pps is derived directly from the 10 MHz by
division. Since the OCXO is phase locked to the GPS, the PPS follows
along. Indeed they have the usual “reset the counter” stuff when things
are big time
Roger,
Bob's idea is a good one. Your last Oct screen shot shows DAC=+0.475V. Try
setting
DAC=+0.5V. Don't even need a counter since L H shows osc error. Hope that DAC
does
not hit a rail. If this does achieve a steering lock then be sure to set the
DAC initial value
using & >> I. This
necessary you could update LH to version 6
https://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/
Nigel GM8PZR
Date: Tue, 24 Sep 2019 13:32:18 -0400
From: Roger Rehr W3SZ
To: time-nuts@lists.febo.com
Subject: [time-nuts] Am I doing something wrong?
Message-ID: <13a08
Thanks to Bill and Mike for the very helpful info!
Unfortunately, doing warm reset, cold reset, factory reset, multiple
self surveys did not solve the problem.
Forcing Disciplining to Enabled did not help.
Tuning the oscillator did not help.
I can manually control the DAC voltage using
Hi Bill,
Thanks for the note!
I leave the Trimble Thunderbolt powered up all the time because since
the last rollover in April it takes a long time to find the satellites
and it doesn't give 10 MHz output until it has found the satellites for
the first time, so none of my gear that is fed by
How long has unit been powered on?
GPS looks ok but osc is not locked, osc error is high at 500K ppt,
should be below 50ppt. DAC shows no activity.
Give it time (maybe an hour) to see if it goes from 'Power-up' to 'Normal"
On Tue, 24 Sep 2019 13:32:18 -0400, Roger Rehr W3SZ wrote:
>HI All,
HI All,
I am wondering if I have set up my Trimble Thunderbolt wrong.
I have corrected for roll-over and everything looks good in Lady Heather
but the Thunderbolt stays in Power-up mode according to Lady Heather,
and is always "doing fixes" even though I have entered the lat and lon
for a
12 matches
Mail list logo
