Hey guys,
I am having quite a debate with a group of hams and cb'ers about the subject
of RMS power. I have been a Ham for almost 44 years and have never had
anyone deny that there is such a thing as RMS Power. I am aware that there
are other amplifier manufacturers on this reflector and I would like some
input on how to calculate RMS Power of a linear amplifier. I have heard or
seen in a book somewhere that Average power is equal to the RMS voltage
times the RMS current. It seems to me that if one is measuring RMS voltage
and RMS current, the product would be RMS power but it also seems that the
reference that I read that said otherwise was one of the main respectable
ARRL OR Orr handbooks.
One of the gang that I have had the discussion with says that when you
measure a modulation envelope peak to peak symetrically modulated signal
across a dummy load with a calibrated scope and calculate the power using
Esquared/R = P, that the Bird 43 will show 1/3 of that value when looking at
the dead key instead of 1/4. He therefore thinks that the Bird is a POS. I
happen to like the Bird 43 and have a lot of respect for it. Has anyone here
got a comment on that?
It has been years since I had everything set up on the bench to make these
measurements accurately but I would swear that when I used to frequently
make these type of tests that I came up with carriers that were 1/4 the
modulated peaks. I know that the modulation envelope is double the size
during 100% modulation and that calls for 4 times the power of the dead key
value. I also am aware that the carrier does not actually change in size
and that the modulation is a mixing process.
Billy
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