[time-nuts] FTS4060 C Field Time Constant
John Ackermann N8UR
jra at febo.com
Thu Feb 17 17:12:39 EST 2005
Brooke Clarke wrote:
> Hi John:
> The only reason I saw this was because the plot had a steep positive
> slope, then 24 hours later appeared to be perfect, now a few days after
> that obviously has a negative slope. My initial estimate of the time
> constant, based on the perfect performance, of 1 tau = 3 hours, was way
> off. The real tau is more like 1 day. So I'll wait another day before
> making the next adjustment.
> Do you have plots that cover longer time periods?
I've done lots of short runs while tweaking this thing... I plan to let
the current run go until at least early next week, when I want to do
some equipment reconfiguration that will require shutting the counter
(but not the Cs) off.
I just acquired three HP 5334A counters (great TICs with 2ns resolution,
1U rack height, and no fan -- and in the $125 range on eBay) to use for
long-term monitoring. I plan to monitor the 5061A continuously vs. GPS,
and the 5065A Rb vs. the 5061A. That'll free the 5370B up from one-off
measurements where I can use the better resolution to get results more
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