[time-nuts] Tbolt temperature sensitivity.

[Bob kb8tq]

Hi

Back a while, I ran a fleet of TBolt’s and other GPSDO’s for quite a while. 
They all ran into HP counters to monitor the PPS outputs. I never saw
any of them hit or slip at the 100 ns level. Indeed different GPSDO 
firmware does the time / frequency tradeoff differently.  I’ve also run them
against various Cs standards. The results there were pretty much the same. 

None of the environments I was running in were very crazy. They all held a 
couple degrees C and the cycles were in the one hour-ish range. 

Bob

> On Apr 8, 2018, at 8:30 AM, John Green <wpxs472 at gmail.com> wrote:
> 
> I don't use what LH says about temperature. I compare the 10 MHz output to
> something else. With two Tbolts sitting about 2 feet apart on my bench,
> both fed from the same antenna, both with factory settings, when the heat
> kicks on, I see a change in the difference between the two. Comparing a
> Tbolt to another, different GPSDO, the effect is even greater. Next step is
> to compare the Tbolt to a rubidium source that has been adjusted to match
> the Tbolt as closely as possible at a stable temperature. I suppose you
> could say the the Tbolt stays *locked* to GPS since the difference never
> gets to 100 nS, meaning they are always within 1 Hz. What I usually see
> when comparing the Tbolt to another, different model GPSDO is that the time
> difference between the two 10 MHz signals slips at a fairly constant rate,
> going from zero past 100 nS, and then through zero, over and over. I also
> tried comparing the 1 PPS and the time jumped around quite a bit. Since I
> plan to actually use 10 MHz instead of 1 PPS, I decided to quit looking at
> 1 PPS.
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