> this was a regulatory issue. Until sometime in the 1980's the
> FCC specified that the DC Power Input to the Final Amplifier stage was
> the Power of record. In other words, the actual output power was never
> considered for purposes of testing a station's compliance with the
> rules.
In the days of link coupled outputs and open wire feeders, rather than
standard impedance coaxial cables, it was easier to measure it this way.
Another detail was that you could run up to 900 watts input without full
metering, and above 900 watts you were required to have both the plate
voltage and current metered.
>
> The ones who lost out on this rule change were the AM operators. They
> had been allowed to run 1000 Watts DC input power, netting perhaps 500
> Watts out.
Only the final PA input power was included, not the modulator power.
With a push-pull class C final RF PA and 1000 watts DC input you could
perhaps have 75% efficiency, resulting in 750 watts of unmodulated
carrier output, and at 100% modulation that could be 3000 watts output
on the modulation peaks.
> was to be measured as the Actual Output Power, they set the maximum
> Amateur Output Power as 1500 Watts PEP. This meant that the AM operators
> had to Reduce their Carrier Power to 250 Watts to comply with the new rule.
>
I think you can have a 100% modulated 375 watt carrier and just hit 1500
watt peaks.
With some many OTs accustomed to the final PA input power as the way to
express a rigs power rating, what company would want to start using the
output power in their advertising when it is only half as impressive.
DE N6KB
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