[Elecraft] Does the KPA500 put out 500 watts in all modes?

[Lyle Johnson]

In the KPA500 manual the duty cycle is indicated as 10 minutes on, 5 
minutes off at 500 watts output.  This could be RTTY, FM, Olivia 500/8, ...

This is limited by the ability of the amplifier to get rid of the heat 
created by the transistors.  That's why I indicated it is a thermal 
issue.  If you have cold enough air, in sufficient quantity, and flowing 
toward the KPA500 intake area, you can probably run for hours key down 
with 500W out...

73,

Lyle KK7P