[Elecraft] Measuring SWR (Long)

[Don Sanders]

Since no one has answered your question. I will venture a
supposition that many know but few will speak out.
And some still remember their CB days and the erroneous
advertising saying the power is lost.
Reflected Power flows back down the feed line and is subjected
to the normal feed line loss. It then is "reflected" back toward the
antenna, again subject to the feed line loss, where some of it is
radiated and some reflected again.
This continues until the power is dissipated. The book "Reflections"
 has a very good but somewhat technical explanation.
Therein also is the reference to forgetting about striving for the
"Holy Grail" of 1:1 SWR.
And concentrating on getting it low enough that the transmitter will
supply full power output. Also using the best low loss feed line and
proper matching when possible of the feed line to the antenna.

Dr. Don W4BWS

God Bless All
Ham Radio does not make the world go round.
Ham Radio is what makes the ride worthwhile.


On Tue, Apr 9, 2019 at 6:43 PM Roy Koeppe <k6xk at ncn.net> wrote:

> "...Let's allow the reflected power to increase all the way to <gasp> 10
> watts! At that point, your SWR would be about 2 to 1. Sounds pretty bad,
> but
> surely if you were stranded in the desert and had to use your KX3 and a
> wire
> to get help, you'd be happy to have a match this good...(etc.)"
>
>
> From memory now, at 2 to 1...feedline voltage nodes and current nodes can
> double -- no small thing when power is 1500 watts; can stress antenna
> system
> components.
>
> 73,   Roy    K6XK
>
>
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