Mauri says:
"Any indirect measurement, i.e. evaluating RMS power through a voltage,
needs calibration."
Hmmm,
The method I use (a 6AL5 with capacitor input filter at its cathode)
delivers an accurate peak DC voltage representation of the corresponding
RMS power at the dummy load. Ultimately, the final accuracy is only
dependent upon that of the DC voltmeter used. Many good VOMs or VTVMs
and modern equivalents there of, such as FET meters, do attain at least
3 percent accuracy and 1 percent is not uncommon. The Z of the 6AL5
circuit is much lower than that of such meters, so there is no concern
of loading effect.
Seems to me the above method is for practical purposes inherently self
accurate and "self calibrating" with any decent voltmeter.
73, Roy K6XK Iowa Outback
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