Statement A:
> increases. If matched feedline loss is very low, the SWR can be very high
> and feedline and antenna efficiency nearly 100% even in a mismatched
> condition.
>
> I operate lines with SWR exceeding 20 to one, and don't even give up a
> fraction of a dB doing so."
>
Statement B:
> The above statements are perhaps the biggest misconception in the
> amateur hobby regarding antennas. Antenna VSWR does reduce antenna
> gain. No question. If you feed an antenna with a 20:1 VSWR you will
> give up 7.41 dB of radiated power. VSWR results in a mismatch loss
> regardless of cable attenuation.
I don't think A & B are using terms with the same definitions.
A) seems to construe the word "gain" as an independent concept relating
to the antenna only which assumes that power can be gotten to the
feedpoint at whatever impedance. SWR is a concept which relates the
antenna's feedpoint impedance to a 50 ohm resistive reference source.
B) seems to construe the word "gain" as a systemic term and construes
SWR at the transmitter output. Losses occur in the *SYSTEM* predictably
due to the interaction of mismatched components.
Both seem right if taken in the sense of their implied definition of
"gain". I do have a question for B), however. In the statement "VSWR
results in a mismatch loss regardless of cable attenuation". My
understanding of "loss" is power dissipation. If the 7.41 db is
dissipated, and not in the feedline, where is it dissipated? Or do you
intend "loss" as some ratio concept that does not actually dissipate
power?
73, Guy.
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