[time-nuts] My Racal-Dana 1992

[Ed Palmer]

Antonio,

I suspected something like that.

I realized that I've never done a similar test so I'm correcting that 
now.  Both the oscillator and the counter have been off for some time - 
days for the counter due to equipment rearrangements and months for the 
oscillator.  I replaced the 04E oscillator with the 04A oscillator to 
see if the 04A's lower power drain would help a power problem I'm 
having.  It didn't.

I installed the 04E oscillator and set up my 1992 to measure the 
frequency of my Efratom FRK rubidium which has been running continuously 
for about 3 months.  I'm using a gate time of 10 seconds.

The first reading after turn-on was about 370 Hz (yes, Hertz) low.  
After 20 minutes the initial warm-up was complete and the reading was 
238 counts (e.g.  0.238 Hz) above 10 MHz - well within the 1e-7 
specification.  Now, after about 13 hrs, the reading is 78 counts high.  
It's now dropping at about 1 count per hour, but there was a recent drop 
of 4 counts in one hour as it works out the kinks.

It'll take a while to match the drift rate of your graph.  Then I'll 
check the standby drift again.

Ed


On 12/19/2011 10:49 AM, iovane at inwind.it wrote:
> Hi Ed,
>
> my mistake, the test started from cold, but the curve I've posted starts at a
> certain midnight. For completeness, the very initial warm-up is missing in the
> curve. Checking my archive, I see that the test started the previous day around
> 02:22 pm and the reading was 3 mHz higher, and I might have lost a few minutes
> since turning on the oscillators and the beginning of the record. The test was
> aimed at seeing how many days the Racal takes to stabilize around the 1E-10
> level, and the answer was one week. And this is the overall sense of my curve.
> Hence a few minutes less or more were not important.
> But indeed this test is not a good indication of the very first warm-up
> minutes (intentionally not from stby).
>
> Antonio I8IOV
>
>> Hi Antonio,
>>
>> Between you and Charles, I'm getting the feeling that my 04E oscillator
>> is defective.  Yours only moved 15 counts over a period of days from a
>> cold start.  Mine moved 40 points in two hours from standby.  I think I
>> have some testing to do.
>>
>> Thanks,
>> Ed
>>
>>
>> On 12/18/2011 6:01 PM, iovane at inwind.it wrote:
>>> As a contribution to this discussion, I attach a 17-day trace recorded with one of my 1992s on Feb 2008. The counter was counting a LPRO Rb. The test started from cold for both sets. Gate time was 10 sec.
>>> The 1992 is the 02M/04E military.
>>>
>>> Antonio I8IOV