Hi Everyone,
I built this little 2m amp a couple of years ago, it works perfectly in every way..... except for the thermal drift.
Tuned up with key down, 300W out with 12W drive, within a few seconds it droops to under 150W.
Keeping the power up requires *constant* re-tuning of the plate.
The drift is so fast I think it must be within the tube or close to it, there just isn't time for the tank circuit to heat up.
I don't know if I made a mistake in the engineering of the tank circuit, or if the tube is faulty
Open to all ideas about how to fix it.
Thanks
Tim G4LOH
