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Old April 3rd 06, 02:11 AM posted to rec.radio.amateur.antenna
Richard Harrison
 
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Default Current through coils

Ian, GM3SEK wrote:
'There are several methods of finding current distribution."

"I may be a fool, but I`n not the fool to be pitied because I disagreed
with Terman. On page 893 of the 1955 edition of "Electronic and Radio
Engineering" Terman writes:
"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)."

This is not news to many thread participants. Fig. 4-7 on page 96 shows
an open-circuited transmission line. At the open circuit there is
maximum voltage and zero current. Except for radiation and loss to heat,
the typical standing-wave antenna would behave much the same as this
ideal transmission line.

Not only does Terman give voltage and current diagrams, he gives a phase
diagram. It shows that whenever the voltage or current crosses the zero
axis (changes sign) the phase angle changes abruptly by 180-degrees.
Phase is unchanging between these inflection points. This agrees with
what Cecil has said all along in this discussion.

Best regards, Richard Harrison, KB5WZI