[time-nuts] FRK-L OK or too tired?

David Forbes dforbes at dakotacom.net
Thu Sep 7 17:31:24 EDT 2006

James and Brooke,

Thanks for the informative replies. I have done pretty much what you 
suggested. The result is a nice sloped line in the positive direction, 
indicating that the FRK-L Rb source is running fast at a rate of about 

I checked the lamp and crystal osc monitors and both are within spec. 
The crystal mon was 5V (2-16V is the suggested range), so I adjusted it 
up to 10V with the range adjust trimmer.

I don't know if an FRK-L running for 13 years is expected to be 1E-9 
high in frequency or if the unit could use some maintenance. The 
suggested drift of 1e-11 per month would add up to 1.5 e-9 over 13 
years, so it may well be within spec and need some C-field adjustment.

Unfortunately, when it was mounted in its box, the C-field adjust hole 
was covered up. I'll need to power it down and do some disassembly and 
drilling to make that adjustment accessible.

Suggestions? Comments?

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