[CQ-Contest] CQ-Contest Digest, Vol 151, Issue 20

Jim Brown k9yc at audiosystemsgroup.com
Tue Jul 21 16:11:18 EDT 2015


On Tue,7/21/2015 11:59 AM, Robert Chudek - K0RC wrote:
> I have a very hard time "buying" this statement. If a BPF attenuates a 
> harmonic, 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?

Bob,

Both solid-state and hollow-state devices produce a second harmonic only 
a few dB below the fundamental. The primary function of the output 
network is to suppress that and higher order harmonics. The tunable 
output networks provide the additional function of impedance matching.

Here's a web version of a piece I wrote for the current issue of NCJ. 
k9yc.com/LocatingStubs.pdf

73, Jim K9YC




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