[time-nuts] Thunderbolt test results
kilodelta4foxmike at gmail.com
Fri Jun 11 21:54:12 UTC 2010
I changed the disciplining time constant on my Thunderbolts and you can
improve it (over the 100 second default). I changed it to 200 sec, then
ran a day, the 300 sec, ran another day, etc.
One unit was best at 400 seconds, the other unit at 600 seconds. What
you should see is less movement in the frequency as you increase the
time constant, and then at some point, it will overshoot and take longer
to recover - then you back up.
In the Thunderbird Monitor program, Setup drop down, Then Disciplining,
then change constant in Loop Dynamics box. AFter changing it, press Set
Dynamics in the Loop Dynamics box, then Save Segment on the very bottom.
You can exit and come back to confirm it took the change.
Peter Vince wrote:
> HI Bob,
> 10 nanoseconds at the bottom, up to 10 microseconds at the top,
> in three logarithmic sections.
> Donal: Is the time-constant at its default of 100 seconds, and was the
> above plot taken shortly after turning it on? There has been lots of
> talk on here about tweaking the performance. Increasing the
> time-constant to between 500 and 1000 seconds should help, as will
> stabilising the environmental temperature. Let it run for a few
> weeks, and the oscillator will settle down, and you should get some
> better results.
> On 11 June 2010 14:20, Bob Camp <lists at rtty.us> wrote:
>> The vertical axis on the plot is pretty tough to read. What is the scale?
>> On Jun 11, 2010, at 8:43 AM, Donal G wrote:
>>> Hi Guys,
>>> I bought a Thunderbolt device recently. I have done some
>>> 10Mhz frequency tests in comparison to a Cesium reference.
>>> Attached is MTIE plot. Have any of you done similar tests? any comment on
>>> my results?, is this normal operation when locked to the GPS? I was
>>> expecting better results that this!
>>> <TBOLT -MTIE-small.JPG>_______________________________________________
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