On Fri, 15 Aug 2003 07:45:32 GMT, "George, W5YR"
wrote:

About all that anyone needs to know about an amateur radio amplifier
(transmitter) in order to use it properly is the output power level and the
required load resistance.

Hi George,

And us folk need never worry about what is beneath the hood as long as
we don't need a mechanic. Sheesh, haven't you learned to turn the
knob until the meter is full scale? All you have to really remember
to push the button before you talk!

The latter is usually 50 ohms for a variety of
reasons, most of which relate to convenience, availability of coax cables,
test equipment impedance environment, etc.

For which us same folk STILL don't give a fig. Are you some sort of
salesman? Who uses coax when telephone wire is free? You got stock
in this cable stuff? I got satellite and I don't need it.

Beyond those values, there is
nothing about the amplifier design which is used in designing and adjusting
the remainder of the tuner, transmission line and antenna system.

What are you talking about designing? Is your charge card void? Do
the sales clerks ignore you? Have you consider stitching your own
semaphore flags for a hobby instead? At least no one would laugh as
much for all the arm waving.

The power
level is of importance only in telling us how much voltage and current is
involved in various parts of the system.

None of us folk even think of voltage or current, this impotence is
not needed to make a contact. What's the point?


The result is the ultimate in convenience.

Something that us folk take for granted and never give a thought to
because it is exactly that: convenient. Are you writing a magazine
article no one reads? I hope you include lots of pictures. I prefer
Reader's Dogma myself.

We need have no intimate
knowledge of "what is in the black box" in order to use it properly.

Us folk would ask "what is in the black box? What are YOU talking
about?" My boxes are brown like any from the liquor store. The only
black box I've seen was at the cemetery. I don't think I will worry
how to use THAT properly - thank you!

In
fact, even if we had full knowledge of all the particulars of the design, we
would still use only its required load resistance and power levels
associated with it modulation waveforms, etc.

WE? You don't talk like one of us folk!


Our modern amateur transmitters and amplifiers even have a convenient meter
on the front panel that tells us when we have met our obligation to provide
a 50+j0 ohm load. It may be labeled "SWR" and calibrated in an unusual
scale, but the important thing is that when it reads 0 or "1:1 SWR" that
tells us that we have met the load resistance obligation - nothing more or
less.

Who looks at that - are you one of those goggle-eyed professors that
try to 'splain the meaning of life? You missed that by a country mile
and still don't seem to have learned about what knobs are for. Twist
one and push buttons until someone talks back. Your black box
obviously has none of the modern conveniences, is it a telegraph?


I think that a great deal of confusion over this whole issue comes from two
sources:

1. vague efforts to apply the infamous "Maximum Power Transfer Theorem" from
the early days in undergrad EE school; and

Us folk never went to this underground school, nothing to be confused
about at all. Are your problems from being a squinty-eyed miner?
Maybe that's why you can't read these meters. Pull the blinds and
take a load off your peepers.


2. confusing an r-f transmitter output stage with the classical "signal
generator" with a dissipative 50-ohm internal resistance.

What language are you trying to talk?

Forget both of those irritants and concentrate on the required load for the
transmitter, which the designer will provide and insist upon, and then
adjust the antenna system to provide that load and all will be well.

Gawd this is complexity for its own sake, you white coated pencil
necked geeks need to get a life. If you are looking for the good
times, pop the cap off a cold long-neck. I hope you don't need a
glass, you would strangle fun out of TV.


At no point will anyone, including the r-f amp designer in all likelihood,
know or even care what the so-called "internal resistance" of the amplifier
happens to be. He demands only one thing: the specified load resistance.
Given that, his design will deliver the required power, efficiency, heat
load, harmonic content, distortion levels, etc. etc.

Infernal resistance is right. distortion is what I don't want to hear
and what you are spouting on about is rattling the cone on my speaker.


I know of no instance in the design of everything connected to the output
port of the transmitter where there is need to know anything other than the
required load resistance for the amplifier and the power levels (average,
peak, etc.).

Is this bragging or complaining? Talk to your chaplain for relief.


Why do folks make this so complicated, Ian?

73/72, George

Oh! a philosopher hmm? About the only complication is the broken
lever of my Lazy Boy. Do you have a screw driver? Drink it college
boy, but don't ralph on the couch when you pass out.

73's
The mythical lurker.... ;-)