LF: MF: CQ stopped, problems

[N1BUG <paul@n1bug.com>]

I was forced to stop calling CQ on JT9 at 2320 UT when my PA again 
became unstable.
This is the same dual band PA I am having so much trouble with on LF.

On MF it will make about twice as much power into the antenna before 
it has problems.
On MF it is much more efficient with the FET running almost cold 
compared to very warm at half the power level on LF.
On MF it takes less power to drive it. In fact with the bias at zero 
volts I have too much drive.
It is OK at first but after several minutes it becomes unstable. 
Nothing is warm to the touch so I don't know why. I think it is time 
to give up on this PA and wait until I can try something else.
73,
Paul N1BUG FN55mf