[time-nuts] Austron 2010B possibilities?
cfharris at erols.com
Sun Feb 11 17:13:15 EST 2007
John Ackermann N8UR wrote:
> Hal Murray said the following on 02/11/2007 01:32 PM:
>>> I had a thought, though -- would it be a worthwhile exercise to use
>>> the 2010B as a cleanup oscillator following my HP 5061A cesium?
>>> By the way, the 2010B has three loops, presumably phase, frequency,
>>> and aging. The first loop has selectable time constants of 5, 250, or
>>> 5000 seconds; the second loop is 50,000 seconds, and the third loop is
>>> 200,000 seconds.
>> What sort of crystal is in the 2010B and how does it compare to the one in
>> the 5061A?
>> Is the cleanup coming from a better chunk of quartz or better software/PLL?
> The 2010B has an Austron 1150 oscillator, the same one used in the 1250A
> standard and the 1210D portable clock. It has very respectable
> specifications (similar to 10811).
> I think the interesting question is whether the short-constant loop is
> clean enough to give an improvement over the Cs oscillator with its 1 or
> 2 second loop to the Cesium beam. I suspect that maybe the 250 second
> first loop might be the optimum for this situation; the 5000 second
> probably makes more sense when hooked to a noisier LORAN-derived signal.
I used to use a 2010B as a disciplined standard to a loran receiver. It
really didn't help much. The problem is it's crystal was a good one, but
the step size of the servo loop that controlled the crystal's VCO input was
way too coarse. I recall it was as bad as a few parts in 10E10 per step...
So, on average, you were right there with the USNO's C-Beam standards, but
on the short term, you were dithering about some point with a few hundred
second period on the dither.
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