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Old February 26th 07, 11:00 PM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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First recorded activity by RadioBanter: Dec 2006
Posts: 1,169
Default tuner - feedline - antenna question ?

Cecil Moore wrote in news:QeJEh.2909$8x.1740
@newssvr14.news.prodigy.net:

Owen Duffy wrote:
Cecil, it seems that between the two of you, you are constructing a
picture that (in a lossless line for simplicity) if the Bird 43 reads
100W forward and 50 watts reflected, the power radiated (ignoring
antenna ohmic losses) is 100W, but 50W is reflected toward the
transmitter... but that's allright because the 50W will be reflected

by
a Zo matched PA, and energy is conserved on the line.


Please don't insult our intelligence. If the Bird reads


Of course it is nonsense, but it is a logical development based on Jeff's
words "What you are describing could be called 'transmitted' power or
power delivered into a mismatched load, but that it different from
forward power, or the power delivered by the source" and your words "For
systems
Z0-matched by an antenna tuner, the situation becomes trivial to
understand. The reflected energy is re-reflected by the Z0-match provided
by the properly tuned antenna tuner".

The steady state solution of the ratio of V/I at the input to a real
transmission line section (ie lossy) that has a load of some arbitrary
impedance is solved using equations that do not include forward and
reflected power terms. The power at any point is the real part of
V*conjugate(I) at that point, no matter whether it is at the source,
load, line input, output or anywhere along the line.

Owen