[AMPS] Conjugate Matching and Efficiency

[Jon Ogden]

on 5/28/01 5:16 PM, Tom Rauch at w8ji@contesting.com wrote:

> The reason this argument continues is because many like to think
> the model we use to "black-box" the source is actually what the
> source looks like inside.

I discovered a very apparent reason why this is so.

I was cruising through my 1987 ARRL handbook the other day (yes, I have a
newer one, but I am more familiar with the old one).  In the PA section, it
does the VERY thing Tom says you can't do.  It talks about efficiency based
on the resistance of the source.  It goes inside the source model and acts
like there is a dissipative resistance inside.  They even show this nice
graph of efficiency vs. match vs. power transfer to buttress this "fact."

Most hams have not gotten a 4 or 5 year degree in Electrical Engineering.
Of those that have, many took few if any RF classes.  So we have a ham
populace that reads a supposedly authoritative text (after all, it IS
published by the League) and believes it as gospel truth.

I should look in my 1999 handbook to see if this error still exists.  If it
does, then the next person to re-write that section should remove it!

A lie, if told often enough, becomes believed as truth.

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."


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