Hi Bill,
Running a test with my Flex 5000A (PSDR ver 2.6.4) on 40 meters I see
pretty consistent results when using the PowerSDR "Tune" function set to
a power level of "100" to produce a steady carrier into a dummy load:
Flex Fwd Pwr meter display = exactly 100 watts
Nye RF Power Monitor (PEP watt meter) = exactly 100 watts
Palstar PM2000AM (PEP watt meter) = a bit over 100 watts (best guess
about 103 watts)
Drake W-4 (AVG watt meter) = 105 watts
Speaking into the station mic while in the SSB mode (with the ALC
bouncing around between -5 dB and -3 dB and now and then reaching -1 dB)
I see the following results:
Flex Fwd Pwr meter display = 57 to 85 watts
Nye RF Power Monitor (PEP watt meter) = 50 to 100 watts (10 to 20 watts
when set to AVG)
Palstar PM2000AM (PEP watt meter) = 65 to 100 watts
Drake W-4 (AVG watt meter) = 15 to 20 watts
Using the "Two Tone Test" in the PowerSDR Tests tab with the Power field
set to 100 and TX EQ switched OFF I see the following results:
Flex Fwd Pwr meter display = 99 watts
Nye RF Power Monitor (PEP watt meter) = 105 watts (90 watts when set to AVG)
Palstar PM2000AM (PEP watt meter) = 110 watts
Drake W-4 (AVG watt meter) = 98 watts
(Note that during the PowerSDR "Two Tone Test" the ALC indicates a
steady 1 dB of ALC compression)
All of my external power meters are analog but they seem to be fairly
trustworthy. Note that I see similar results when looking at the output
of my Kenwood TS-590S. The Kenwood exhibits roughly 30 watts of
overshoot on the initial keying or voice peak and the analog meters
definitely show that. I do not see any indications of overshoot with my
Flex 5000A. The software "Fwd Pwr" meter in PowerSDR seems to be in
close agreement with steady tone signals but is stingy with SSB peak
readings with peak indications about 15% lower than the external meters.
The only conclusion that I've reached from all this is that my wife
should definitely buy me an LP-100A digital watt meter for my birthday.
73,
Rob W1AEX
--
One thing I'm certain of is that there is too much certainty in the world.
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