> True enough, but don't forget the power from the
modulator. In rough
> terms, you could put as much power into the modulator as
you could in the
> carrier (the modulation power averages out in the "DC
Power to the final
> stage"), so you could roughly double the DC output in RF
terms.. about 1.5
> kW or so RF power.
It takes 500 watts of sinusoidal power to 100% modulate a
1KW plate input transmitter, not 1KW! The highest
requirement for average modulator power occurs with sine
wave modulation.
And, of course, that's average power, not peak
> envelope, so, with the right modulation (heh, heh)... say
300% positive and
> 100% negative, you could actually get a pretty darn high
PEP.
At about 130%-150% positive modulation distortion becomes
objectionable, very few amateurs ever ran more than 100%
positive peaks intentionally and most rigs barely handled
100% without flat topping on peaks.
Aside from the longer duty cycle and average power, the only
real difference in an antenna component or matching system
would be the peak power is roughly 4X the average or carrier
power. A full gallon input on "old days AM" would be like a
3KW or less SSB PEP output signal, and not as much short
term average power as a legal limit output CW or RTTY
transmitter has today. Heating is greater now (on carrier
modes like FM, CW, RTTY) and voltage peaks are a bit less
now. Peak voltage is perhaps 70% of what it was with AM, and
average power is actually more now on CW and RTTY than it
was with old AM.
The fact is enameled wire baluns suck big time. Most old
baluns are very poor compared to most new current baluns.
73 Tom
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