John Sandin wrote:

Here's the link to my project website..

http://www.kcnet.com/~oyster/transmi...ansmitter.html


Your heatsink (at least, I think it's the heatsink) is
inefficient (finless), and you mentioned using lots of
heat sink grease. You *can* have too much grease.
Putting in a bigger sink with fins and a small amount
of heatsink compound won't fix your problem - but it may
be a good idea, once you have fixed it.

The fact that the xsistor is heating up at least means that
the rig is "making power". If we assume that the power
it's making is RF at the right frequency, then suspect the
output circuit from the collector outwards up to and
including the antenna. And, with your antenna at 7 feet,
and fed by a questionable mix of coax, it may be the source
of the trouble.

Try feeding the rig into a good 50 ohm dummy load and see if
that allows the transistor to run cooler.