Farhan;
I switched out the silpads in my DE for Alumina Ceramic insulators. The attached thermal image photos show the stock silpad under the right FET and an Alumina Ceramic insulator under the left FET. The transmitter was key-down at 30 Watts for maybe 5 seconds. I saw a pretty dramatic difference between the two. I had planned to take some better images, as well as make a short movie showing the temperature difference resulting from an insulator change-out, but the FET on the right was having no more of it and shorted out.
No doubt that Aluminum Nitride insulators would work even better. I was able to get a lifetime supply of Alumina Ceramic insulators from Amazon in two days for not a lot of $$, so I'm happy with this solution.
My conclusion is that there is room for improvement from the stock silpads.
I posted a video in the files section a couple months ago - it shows that the FETs stabilize in temperature relatively quickly.
73; Steve, N3SB
