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Old November 22nd 08, 07:14 PM posted to rec.radio.amateur.antenna
Richard Harrison Richard Harrison is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 588
Default Displacement current

Art wrote:
"So now one must determine where the reflection occurs and science
puports that it is not at the end of the antenna!"

Check your 1955 Terman opus. On page 887 is Fig. 23-24 showing current
on a 1/4-wave antenna. Current discontinues at the tip.

On page 893 Terman says:
"An antenna can therefore be regarded as a resonant system with
distributed constants. As a result, the impedance of an antenna behaves
in much the same manner as does the impedance of a transmission line
(see Sec. 4-7)."

Sec. (4-7) says on page 99:
"Similarly, with an open-circuited receiver, or with a resistance load
greater than the characteristic impedance so that the voltage
distribution of the open-circuit type (Fig.4-5),
the power factor is capacitive for lengths less than the distance to the
first minimum. Thereafter, the power factor alternates between
capacitive and inductive at intervals of a quarter wavelength, exactly
as in the short-circuited case.

If Cecil were asked where a reflection occurs on an antenna or a
transmission line, I`d wager he would reply, at the same place the
impedance discontinuity occurs.

Art has asked similar questions several times. Art should answer some
questions. What has his examination of Gauss` work produced that allows
quicker, more precise or easier answers to the problems readily solved
using Maxwell`s equations? What mistake has Art found in Maxwell`s
equations?

Best regards, Richard Harrison, KB5WZI