At 23.31 07/09/2006, you wrote: >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 >1e-9. > >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?
David, drill an hole, turn the trimmer and zero it. It's a perfectly legitimate offset, and since you see a straight line it's working well. Only it needs to be zeroed. Do it after a few hours of warm up, then check it for a week and zero again. It will stay in the usual +/- 1E-11 per day. If it has the EFC option, may be that the external voltage was used to correct the drift, so it may have had even a smaller drift over it's life. Marco IK1ODO _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
