[CQ-Contest] seeking 9band bandpass filter unit,

Bob Henderson bob.5b4agn at gmail.com
Tue Jul 21 17:02:54 EDT 2015

RF amplifiers are not truly linear.  The outboard amplifiers we use in ham
radio are for the most part biased Class AB.  You need to read that part of
my last post in which I discuss the harmonic performance of class AB
'linear' amplifiers.  Hopefully this should help you buy my statement on
the usefulness of BPFs between transceiver and amplifier in attenuation of

Our power amps generate heavy duty harmonics all by themselves.

73 Bob, 5B4AGN

Bob Chudek K0RC wrote:

"While BPFs certainly do attenuate harmonics, this is all to no avail when
the BPF is installed between transceiver and amplifier."/

I have a very hard time "buying" this statement. If a BPF attenuates a
let's say, 30 dB, that would be 30 dB less harmonic energy being fed to the
amplifier. If the amplifier is truly "linear", how does it recoup this 30dB
of harmonic power that is no longer being fed into the input?

73 de Bob - KØRC in MN

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