[Elecraft] K2 drift problems?

[Brian Machesney]

There is a difference between TCXO and OCXO which seems to have gotten
lost in this thread. A TCXO is a temperature COMPENSATED crystal
oscillator; an OCXO is an OVEN CONTROLLED crystal oscillator. The
temperature of a TCXO is compensated, not controlled, so it draws less
power than the OCXO's oven. 

Both contain actual oscillator circuits, so they might not directly
replace the crystal in a given design (e.g., K2). Both oscillators have
very good phase noise performance. A TCXO also contains a memory into
which the manufacturer places values that, when converted by an ADC,
push on a varactor diode to compensate the crystal oscillator's
frequency according to the crystal temperature measured by yet another
on-chip circuit.

Brian K1LI