[Lowfer] PA transistor getting hot - need advise

[John Andrews]

Andy,

That circuit is intended to produce a nice square wave, with one 
transistor turned on and the other turned off at any time. If there is 
an overlap, heating will result, and the amplifier's efficiency will go 
down. If you have a scope, particularly a dual-trace model, you may want 
to poke around. With a 50 ohm resistive load, any deviation from a 50% 
duty cycle square wave should be obvious.

If you look at the schematic at:
http://www.w1tag.com/tagtx.htm
you will notice two extra diodes at the transistor bases. These were 
suggested by Bill Ashlock, and may be worth a try.

Another approach would be to use an MPS6652 for the PNP transistor, and 
an MPS6602 for the NPN. Despite what my schematic shows, that's what I 
have been using for the last several years, again at Bill's suggestion. 
The current gains of both parts are higher, and better matched, as Mike 
mentioned.

John Andrews, W1TAG