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Old September 27th 05, 09:18 PM
Richard Fry
 
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"Reg Edwards"
But I'm afraid you are wrong. The meter correctly indicates
SWR on the feedline when it is located at the antenna end
of the line.

______________

Remove the feedline, and connect the 100 ohm antenna through the SWR meter
calibrated for 50 ohms, directly to the transmitter. The meter has a
reading. The measurement will have the same value as before, neglecting any
adjustment for having no line loss now. But there is no feedline, so how
can there be any SWR on it, you write.

The fact that there is not enough transmission line length in the system for
literal standing wave maxima and minima to develop on it does not mean that
reflections do not exist in the output load system. It is the value of
those reflections that determines the corresponding value of SWR.
Reflections can be measured by appropriate instruments regardless of the
length of line in the measured system, or even the existence of any
transmission line at all.

The convention of the professional engineering community for many decades
has been to convert incident and reflected waveform samples into the
corresponding value of SWR, no matter if there is insufficient line length
in the system for the corresponding maxima and minima to develop fully on
it. It doesn't matter, electrically. Your constant diatribes stating that
it does is a futile exercise.

Disable the SWR protection in your ham tx and key it to full power into an
open or short. There is no transmission line where standing wave maxima and
minima could exist, but your tx will burn up anyway.

Maybe save your response until tomorrow morning, when your Merlot buzz has
worn off

RF

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Old September 27th 05, 09:58 PM
Richard Fry
 
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"Reg Edwards"
But I'm afraid you are wrong. The meter correctly indicates
SWR on the feedline when it is located at the antenna end
of the line.

______________


PS:

In this example the mismatch between the antenna and the line is the source
of the reflection that results in system SWR. Convention is to state that
the SWR belongs to the antenna, not the line -- although the added stress on
components applies only to the line and tx, and not to the antenna.

An ideal SWR meter will read that antenna reflection to have the same value
when installed at either end of the line, or anywhere along its length
(assuming
a perfect 50 ohm line, and neglecting line loss).

RF

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