No one has mentioned amplifier efficiency at differing power levels.
-John NI0K
Andy Durbin wrote:
"They bias the LDMOS devices at 1 amp each. That is minimal in overall heat when you
are pulling over 40 amps at high power."
You beat me to it. My KPA500, keyed but with no RF input, showed 0.5 A at
76.7 V. That's only 38 W which is a small part of the 400 W plus PA
dissipation seen in some operating conditions.
All my measurements of PA dissipation take PA DC input and subtract RF output
so my data include dissipation in the LPF. It would be interesting to separate
the dissipation in the finals from the dissipation in the LPF but I don't know
how to do that without modifying the amplifier.
73,
Andy, k3wyc
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