[Amps] FCC Denies Expert Linears' Request for Waiver of 15 dB Rule

[Manfred Mornhinweg]

Bill,

I have experienced several such cases of fellow hams blowing crud all 
over a band, and "not hearing" those who report the problem. But most of 
the offenders I have heard are operating factory-made equipment! Very 
often they use a 100W radio to drive an amp that needs 50W or less of 
drive, and don't connect the ALC line. Radios with slow-acting ALC are 
also famous for causing IMD blasts and key clicks without even needing 
an amp, and there are many. But the most usual way of producing lousy 
signals is by intentionally defeating the ALC of the transceivers. In my 
environment they call it "liberating" the radio, because the poor radio 
was tied down to just 100W by the evil manufacturer, and by defeating 
that "brake" it can produce 150W or so, when turning the mic gain to 
full and then screaming into the mike, right?

I try to gently educate such fellows whenever I have an opportunity, but 
many simply don't want to listen.

Sometimes radios develop faults that make the transmission dirty. I 
remember a case of one station running a factory-made radio with a bad 
PLL. It had an extremely high phase noise, and would transmit modulated 
noise over a wide part of the band. That guy did reply to my report, and 
told me that he had the same very high noise on RX, so he thought that I 
was hearing what he thought was his local noise floor! I tried to 
explain to him that probably his radio was faulty, and I went on to 
explain about phase noise in frequency synthesizers and how that can 
affect both TX and RX, but he totally rejected my suggestion that his 
radio was faulty. He replied that his radio was putting out "the full 
100 watts and some more", and thus couldn't possibly be faulty...

There is a ham a few hundred km from my place who runs a homebrew PWM AM 
transmitter, with the pulse width modulator running at 20kHz. Apparently 
his transmitter doesn't have enough filtering after the PWM stage, and 
the result is that I can hear him loud and clear every 20kHz, all across 
the band and beyond...  And he has never replied to any of my reports 
about it.

Lids are everywhere, and also new hams who try to do things right but 
just do beginner's mistakes. Personally I'm very apt to forgive someone 
who is testing a homebrew rig that turned out to be dirty, while I have 
some trouble forgiving those who defeat the ALC of their radios. But of 
course any ham who gets a report of causing interference should listen 
to it, acknowledge, and do his best to fix the problem.

Manfred

> This privilege is a double edged sword. About ten years ago I was
> operating during a RTTY contest on 40 meters when I noticed a fairly
> strong blast of white noise all across the band. The noise came and
> went with a rhythm that suggested someone calling CQ. Long story
> short, it turned out to be a fellow on the east coast of the US who
> was using a homebrew class E amplifier. He would not answer me on the
> air so I sent him an email after the contest was over. Never heard him
> again. 
> 
> Such transgressions are rare but they do happen. 
> 
> 73, Bill W6WRT
> 
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