Success! I disassembled the oven and adjusted the OCXO frequency up about 5 Hz. Lady Heather reported the DAC changed from +99.99% with no lock to -90% with lock to GPS. Hopefully I did not increase the frequency too much. The long term aging/drift direction has been down - which caused the loss of lock. At this time the DAC has increased slightly to -90.5 as the system settles.
Paul, I also thought about adding an offset voltage to the DAC, but I was concerned about stability. Adrian, I thought about an access hole, but when I disassembled the oven, a piece of the outer heater was partially covering the adjustment access cover and adjustment. That required careful moving to access the oscillator adjustment. Disassembling (ripping is more descriptive) the oven was not difficult. Putting everything back together was more tedious. A huge thanks for all the replies, links to pictures, encouragement, etc. Joe, W7LUX _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
