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Old March 20th 06, 12:56 AM posted to rec.radio.amateur.antenna
Yuri Blanarovich
 
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Default Current through coils


I've been trying to tell Yuri (and others) that for three years now.


73 Tom

Tom.
You tell that to the RF ammeters installed on the vertical, W9UCW's pictures
on my page!
You can mumbo-jumbo all the theory, you can dream of, but reality shows that
in the say, quarter wave vertical, with loading coil the current at both
ends of the coil is different. Cecil explained the various situation
depending where the coil is placed within the radiator and at overall
antenna curve.

Try this test, no meters necessary (perhaps the aquarium strip thermometer):
Take your 80m Hustler antenna with Hustler loading coil and whip. At the
resonant frequency put about 600 Watts to it for a while. Stop transmitting
and go feel (or read the temperature on the strips) the coil, bottom end and
the top end. Same temperature? Temperature is proportional to the current
flow (same diameter wire) - warmer end - more current.

Then test two: Keep the RF flowing until heat shrink tubing on the coil
starts melting. Where does it melt first? Bottom of the coil or nicely
uniformly as you claim it should?

Then answer Cecil question about his demonstration of different currents at
the ends!
The rest is on my web page as I mentioned, with pictures.

73 Yuri, www.K3BU.us