Don, welcome in the boat. You describe with other words what I am fighting against. There must be a logic behind which we did not find yet. I want to understand what is hidden behind all the setting parameters and find a way to get the 10811 running without degradation but just disciplining the OCXO drift away. But without knowing the logic behind and without a known reference a bit difficult...
Regards Arnold On Mon, 13 Jul 2009 13:15:29 -0700 (PDT), Don @ True-Cal wrote: >Arnold, >I have the same question as well as observations as yours. I have been working >with both the TBolt and Fury connected to two different 10811s. With either >the TBolt or Fury, I can't get the TC large enough to only provide a nudge to >the EFC every few minutes. Both receivers get real unstable and cause large >Freq and PPS swings with large TC numbers. It seems the EFC is providing many >corrections per minute even with the TBOLT set to 300 secs. Anything larger >than 300-500 sec. on the TBolt and EFCD=150 (don't know what the equates to in >secs.) on the Fury will cause instability. I have better luck disabling >desciplining on the TBolt or disconnecting the antenna on the Fury (no command >to disable that I have found) when I need to do a Tau 0.1-10 sec. low jitter >measurement. > Regards... >Don >________________________________ >From: Arnold Tibus <[email protected]> >To: Discussion of precise time and frequency measurement <[email protected]>; >Tom Van Baak <[email protected]> >Sent: Monday, July 13, 2009 1:56:56 PM >Subject: Re: [time-nuts] Trimble Thunderbolt setup optimization and adding >a10811 OCXO >Tom,: >>> Astonishing for me, >>> I found that the 10811 does behave better in undisciplined >>> mode for a limited time: >>This is to be expected. An undisciplined high-quality OCXO >>like a 10811 will be hundreds or thousands of times better >>than the raw output of a GPS receiver at short averaging >>times. This is why a GPSDO exists; it allows the OCXO to >>run almost free for minutes to hours but allows GPS to rule >>for long-term. >yes that is what I thought, but if I do observe correct, TB's >OCXO does not run at all free for minutes. With a time >constant of 360s the EFC and thePPS is surfing up and >down, why, I do not see the need to shift this OCXO within >2 minutes 80ppbs up and pps15ns as well - with this stable >oscillator....what is the driver, the SATs (I think not so)! >Arnold _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
