[Amps] Alpha 87 (not 87A)
Jim Brown
jim at audiosystemsgroup.com
Tue Nov 7 13:00:12 EST 2017
On 11/7/2017 9:44 AM, Steve Wright wrote:
> People seem to visualise all this heinous crap coming out of their
> antenna and taking away everyones' rights, but I challenge any person
> to furnish any sort of valid complaint regarding any harmonic. And I
> mean a COMPLAINT, not someone three doors down being able to detect
> your 3F.
It is a serious mistake to view harmonics as the only product of
distortion. Any mechanism that produces harmonics will also produce
intermodulation, which shows up as clicks on CW and splatter on SSB.
They are two heads of the same snake. We can kill harmonics by filtering
them, but we can't do that with IMD.
K6XX, an engineer who works for Elecraft, mostly on their power amps,
gave an excellent talk on this topic to our contest club several years
ago. In it, he noted that the distortion increases a LOT in a power amp
that is not properly tuned. For solid state amps, this tuning is
accomplished by giving it a matched load, either the antenna itself, or
with an antenna tuner. Bob is my neighbor, and we're both serious
contesters (and also good friends). When I moved in 11 years ago, one of
the first things he did was make sure that I knew how to tune my amps,
and the importance of doing so.
http://k9yc.com/K6XXAmpTalk.pdf
73,Jim K9YC
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