turning the device off sounds like an odd solution for a temperature
Also, usually you’re experiencing frequency drift with temperature,
which can, if your receiver architecture can’t correct, will lead to
Thermal noise will only significantly increase if the temperature shift
is not negligible compared to the effective equiv. noise temperatures of
your system, which /should/ be dominated by the first amplifier stage.
So if I’d suggest anything, it would be just adding a cooler/fan/peltier
element to that, and see if your performance measurably increases, just
to verify it’s a temperature problem at all.