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Old April 11th 06, 05:00 AM posted to rec.radio.amateur.antenna
Richard Harrison
 
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Default Current across the antenna loading coil - from scratch

Tom, W8JI wrote:
"Wave theory is just fine, but it has to be understood it is just a
modeling shortcut and the results cannot conflict with the basic laws of
physics,"

The Quantum theory may replace the wave theory some day, but the wave
theory has always satisfied my needs.

Terman writes on page 84 of his 1955 edition:
"The quantity aq. rt. of ZY is called the propagation constant of the
line. It is a complex quantity, having a real part alpha called the
attenuation constant and an imaginary part beta termed the phase
constant."

On the next page 85, Terrman has diagrams showing behavior of the
voltages of the incident and reflected waves on a transmission line. It
is the same as that on antennas. That`s why the antenna section of
Terman`s book tells the reader to refer to the transmission line chapter
for the behavior of antennas. It`s identical.

I`ve erected and operated countless rhombics in the international
broadcasting service. I`ve underloaded them and overloaded them and in
the process melted plenty of dissipation lines. I can attest that Terman
has it right. Sometimes you have to do what you`ve got to do even when
you know better.

When the dissipation line went away we would cover outh America as well
as Central Europe and get lots of fan mail for our troubles. We
shouldn`t have been getting fan mail from South America but lots of
Central Europeans were living there as refugees from the Axis and from
the Allies. When we covered South America, some broadcaster with a valid
claim on the frequency at that hour and place was being clobbered by
us.. We couldn`t help it. Our job was to save the world and we did it
while sometimes stepping on others in the process.

I guarantee we never put anything even close to 100KW into a dissipation
line. Problem was the Signal Corps rhombic kits were maxed out at 5 KW
and it took time to get bigger resistance wire. 100 KW in a dissipation
line would have melted it in days if not sooner. As it was, standard
G.I. lines lasted weeks while glowing a cheerful red and did not erupt
in a blinding flash.

The wave travels along both wires simultaneously. The wires in the
dissipation line melt at the input end not at the far end where the wire
is smaller. Current does not travel through the line like the utility
power frequency through a string of Christmas tree lights.

Tom needs to get with the reality of the program. His idea is seriously
flawed.

Best regards, Richard Harrison, KB5WZI

 
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