If you ever experiment with these types of transistors, there are 3 things to pay close attention to.
1) Do not skimp on the copper heat spreader. It is required because there is no other way to sink over 1kw of heat dissipation through a single package device without it. The best aluminum heatsink still needs copper otherwise the surface area of the transistor alone, is too small for proper heat transfer.
2) Do not over bias the transistor. Apply just enough bias to produce a clean signal. Pass it by a few hundred millivolts and you could easily pop the gate. For that reason, regulation is critical.
3) Do not overdrive them. Some of these transistor are capable of operating at 23db gain! One watt can produce full output in many cases. Do not think the typical radio can be turned down to safely meet this requirement. The simple 3 resistor, 50 ohm attenuator is usually required to insure peaks do not over drive the input.