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Old August 12th 03, 10:32 PM
Roy Lewallen
 
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Sorry, it's not clear from what you've said just what you're trying to
match to what.

Truly, if you connect a 50 ohm load (be it a resistor, or some impedance
transformed by a transmission line, tuner, or other means -- makes no
difference) to a transmitter, and the transmitter's output impedance
isn't 50 ohms, there will be a mismatch at the transmitter output.

But who cares? Most transmitters are designed to work properly when
terminated with 50 ohms, but that doesn't at all mean that their output
impedances are 50 ohms. And it certainly doesn't affect the SWR on any
transmission line connected to the transmitter. If you were to discover
that your transmitter's output impedance were, say, 10 ohms and you
connected it to a 10 ohm load, you'd have a very unhappy transmitter.
All you have to worry about is presenting the transmitter with the load
it was designed to work into, not what the internal impedance of the
transmitter is.

Roy Lewallen, W7EL

Dr. Slick wrote:
Roy Lewallen wrote in message ...

Almost correct.

The transmitter output impedance has no effect whatsoever on the line's SWR.

Roy Lewallen, W7EL




My point is that if the output impedance really was at a perfect
50 Ohms, then using a perfect 50 ohms transmission line, you can never
match to anything other than 50 ohms.

If the S22 is something other than 50 Ohms (usual case), then a
transformation via 50 ohm coax about a constant VSWR is possible, for
the purposes of matching to a not-quite-perfectly-50 ohms antenna.


Slick


 
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