Hi David,
> So, are we agreeing to conclude that reflected power that is resolved by
> the final tuned circuit of an amp, rig, or antenna tuner is meaningless
and
> to be ignored as irrelevant at HF frequencies?
Not totally in every case. Increased SWR can increase feedline loss, mostly
by increasing current on the line (I^2 R loss).
> I am using "resolved" to mean that the amp or rig is protected from
> troublesome voltage, current and/or impedance's. I am also using it to
> mean that essentially all reflected is re-reflected back to the antenna
and
> directed to its intended destination.
One trip out and back is enough to solve our applications.
Maxwell's book "Reflections" is the best treatment of this and other
problems for amateurs.
> One question: If one adds a group of toroid beads to the coax
immediately
> exiting the amp or rig (some say this helps with impedance stability and
> eliminating rf in the shack), what is the actual result?
Probably not much of anything. The problem usually starts at the antenna
end. By the time you bring the unwanted garbage in the house, most of the
harm has been done. Most antennas, even verticals (because they have less
than perfect grounds), have common mode feedline currents.
I like to stop the unwanted current on the outside of the cable before it
leaves the area of the antenna, not Band-Aid it way back down stream in the
house.
> Is any
> significant loss injected into the system design?
Not a bit. Correcting the problem will add signal. DON'T use a fancy-pants
muti-winding dream balun. Use a regular choke (current) balun. Even coiling
up the coax is often good enough. Roy Lewallen made some common mode
impedance measurements of various scramble wound chokes.
Anyone know where he published the results?? I forgot.
73 Tom
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