ORIGINAL MESSAGE:

JJ wrote:

There is a drop in freq for Pierce and Colpitt after 1 min of
startup. Can be 100Hz.
Serious enough.

JJ

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Sounds like you're driving the crystal too hard and it's heating up.
When something heats it expands and a larger crystal has a lower
frequency. If you want best stability, reduce the drive until the
circuit barely oscillates and make up the lower output with a stage of
amplification.

73, Bill W6WRT