Unfortunately, the exams are going the other way with very little
required in the was of technology ans theory. They have dumbed down the
exams to where, I think my Novice test had more theory than any of the
present exams. Now the ARRL thinks we need an even easier, entrance
level class. Well, the East and West coasts are liberal havens.
We don't need an easier class! As Manfred said, we need one that
requires some technical knowledge. Ain't gonna happen in today's social
climate.
As for ALC, I only know of one manufacturer that has the output power
controlled by ALC with the overshoot.
My transceiver runs 200 out and backed off to drive a high gain tetrode
has no overshoot. I've received a lot of compliments on the signal quality.
Referring to the clean commercial rigs and the ham rigs that let the
user tailor the signal into pure trash. There seems to be a number of
hams that like to add 100 Hz on the bottom of the audio for a more
"natural" sound, then complain when calling stations are off their
frequency by 100 Hz. I ran an experiment with one such station with him
randomly adding and removing the 100 Hz. Even then, he couldn't
understand why I was moving 100 Hz with each change and this was an old
timer.
I like to look inside, but touch nothing. Many of today's rigs require
some sophisticated equipment to properly align. They even require a set
sequence for setting up the audio, that if not followed in order, can
leave the transmitted signal really bad. The companies didn't do ham
radio any favors by making so many parameters accessible to the user!
I've worked with digital for years and know enough that I realize, there
is no way I can repair one of the top end rigs with the possible
exception of the displays, or possibly final module.
73
Roger (K8RI)
On 4/25/2017 4:37 PM, Manfred Mornhinweg wrote:
Some hams go another step further, take the cover off their radios and
defeat the ALC. That goes a good way toward deflecting the needles
even further. And toward splattering all over the band and then some,
of course.
Hams should be asked to pass a test, both about technical knowledge
and mental sanity, before being allowed to operate radios that have
external controls for mic gain and compression level. Those who
haven't passed that test should only operate radios that don't have
these controls, and only operate them with the stock mikes. And the
covers of their radios should be welded shut, just in case! :-)
Joe,
just a small correction:
> The PA must be over driven in order to produce any ALC!
That depends on how it's implemented. An ALC that requires overdriving
is a badly designed ALC. In solid state transceivers the ALC signal is
usually derived from a comparator that starts giving an output when
either the power output reaches a certain level, or the reflected
power does so. If this comparator is properly adjusted so that it
starts giving an output a little before the PA is overdriven, then the
ALC prevents overdriving. Of course if a monkey with a screwdriver
fiddles with that internal adjustment and sets it above the overload
level, the ALC can no longer do its job of preventing overdrive.
---
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