An historical note:
Johnson sold a transmitter rated at 275W, DC power input.
It was called the Valiant or something like that.
I believe this is where the 275W came from (ever wondered
why not 250 or 300?). This transmitter probably had an
output in the neighborhood of 200W. Like my FT1000.
During the heydey of Johnson, you got on AM and had
5 minute transmissions. Thus you can multiply 200W
by a factor of 2 if you are transmitting 50% of the time
for short periods and an additional factor of 2 or more
accounting for peak to average for CW or SSB. Thus
thermally, you should be good for 800W. You are also
good for 800W in terms of voltage breakdown because
200W AM is 800W PEP.
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