I agree with Clark. Increase the size of your heat-sink,
especially if you are primarily using digital modes
It is easy to do. Use a computer cpu sink, or go to some place
like Tractor Supply and buy a strip of 3 in x 1/4 in aluminum
and cut your own.
Sometimes you can find them surplus; the best ones I have found
were originally designed for voltage power converters. They have a lot
of dissipation area in a small footprint. Another good place to look is
in linear power supplies, especially the strips used for the amperage
bypass transistors. Sometimes one can also find good ones in old
stereo amplifiers as well (less so in old TV sets).
Always remember to isolate the IRF510 as the tab is "hot".
john
AD5YE
