JIMMIE wrote:
I have heard there is a process where coax cable is baked in an oven
to lessen the effects of temperature change of the cable on phase
shift. I havent been able to find any information on this process.
Direction to any information on the subject would be greatly
appreciated.

Jimmie
mostly it's done by empirical methods..

The idea is to relieve internal stresses by several temperature cycles,
reducing at least one source of phase change.

In reality, what you want is "consistent and repeatable phase change vs
temperature without hysteresis"... hysteresis or randomness is usually
due to mechanical effects (stick/slip, etc.), so temperature cycling
fixes it.

google for phase-stable coaxial cable and you'll probably find
manufacturer sites that discuss it.

BTW, there's "low phase change cable" and "repeatable phase change
cable", and sometimes one is better than the other in a particular
application.