[time-nuts] Fine frequency adjustment in 5370B

David Kirkby david.kirkby at onetel.net
Sun May 15 15:43:21 EDT 2005

The frequency of the oscillator in my 5370B seems to be a little off - 
at least according to my Standford PRS10 rubidium. Although the latter 
has not been calibrated recently, I suspect the rubidium is more 
accurate than the 10811-60111 in the 5370B, so was intending changing 
the latter to that of the rubidium.

Although when one removes the top cover of the 5370B, the 10811-60111 
can be seen with its adjustment control, I believe this is a course 
adjustment (18 turns is supposed to move it +/- 10Hz, at least on the 

I know you can trim these oscillators with a fine control, using the EFC 
voltage. Is anyone aware of whether this is possible on the 5370B or not?

I have the service manual, and so no mention of it. Neither can I see 
any control, so I guess the answer is probably no. But the PCB the 
oscillator plugs into hidden beneath some shielding, so I am not 100% 
sure there is no pot.
David Kirkby,

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/

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