[Amps] peak reading with AM signals tspa

kenw2dtc kenw2dtc at comcast.net
Mon Mar 28 19:00:02 EST 2005


"I am not an expert on Bird 43 wattmeters..............I was curious as to 
why it was typically 3X and not 4X as modulation theory would predict, for 
100% sinewave modulation"

John,
Using an audio generator at 1 kHz, a scope and the peak reading bird I am 
able to get the 4X peak from my AM transmitter.  I will also mention that as 
soon as the audio generator goes above 1.8 kHz the peak reading bird starts 
to go down.  By the time the audio generator gets to 5 kHz the peak bird is 
reading the same as the non-peak bird, while at the same time the scope is 
showing that the transmitter is still doing 100% modulation with an 
undistorted sine wave.
73,
Ken W2DTC




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