[time-nuts] Brand new OCXO/TCXO reccomenations

[Mark Goldberg]

Note that many (maybe all) TCXOs exhibit a hysteresis effect when the
temperature cycles. The stability reported on the datasheets is only
tested with a temperature change in one direction. Cycling temperature
up and down will result in more variation.  I've seen two or three
times the datasheet variation when cycling some TCXOs between 0 and 50
C and have had to super select for this. I've also seen non monotonic
jumps. Aging is also very significant in the first few months after
soldering.

Mark
W7MLG