[Elecraft] K4D - KPA500 Fault Question + wish

[Andy Durbin]

"Is there data showing more dissipated heat with lower output in solid state amplifiers? "

I have test data for my KPA500 and it's very obvious that this amplifier has higher PA heat dissipation at half power than at full power.  Not just less efficient as a percentage of power output but the absolute dissipation is higher.

At low power the absolute dissipation is lower than at full power but the efficiency is still lower.  The worse place to run a KPA500 is in the 200-300 W output region.  Note also that KPA500 PA dissipation is very dependent on load matching.

I've posted this before but some of my test data can be seen here - https://tinyurl.com/2kdrjmt3

73,
Andy, k3wyc