[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.


73,Jim K9YC

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