RadioBanter - View Single Post

March 20th 06, 12:35 AM posted to rec.radio.amateur.antenna

Cecil Moore wrote:

wrote:

The loading coil, if well-designed and of compact size, doesn't have to
have any significant current taper.

The current taper depends upon where the coil is installed in
the standing wave environment. There is no doubt that the coil
distorts the current away from the ideal thin-wire dipole case.
But that coil does have to have a significant delay, in the tens
of degrees according to Dr. Corum. Since you and Roy mistakenly
used standing wave current phase to try to measure the delay
through a coil, the following posting resulted:

Gene Fuller, W4SZ wrote:

In a standing wave antenna problem, such as the one you describe,
there is no remaining phase information. Any specific phase
characteristics of the traveling waves died out when the startup
transients died out.

Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen
again.

The only "phase" remaining is the cos (kz) term, which is really an
amplitude description, not a phase.

Gene is 100% correct and we all should be grateful for that posting.

Neither you nor Roy have ever made a valid measurement of the
delay through a coil. It is admittedly a difficult measurement
to make directly. Ramo and Whinnery say it "is usually of
prohibitive difficulty".

I think that if Gene believes that, he should redo his math.
73,
Tom Donaly, KA6RUH