"Henry Kolesnik" wrote in message
gy.com...
QST March 2004 page 34, upper left hand corner mentions that at 100 watts
the voltage at the base of an 8 foot mobile whip could exceed 1000 volts
and
arc over a CB-ball. Can anyone plase show me the math?
tnx
Hank WD5JFR

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At what frequency ?

At a frequency of 10 KHz and 100 watts, an 8-foot vertical will have a
voltage across the feedpoint of many thousands of volts.

Calculation is easy. All you need to know is feedpoint reactance and
radiation resistance at the operating frequency. From then on its all Ohms
Law. Calculate the current which will generate 100 watts in the radiation
resistance. Multiply the current by the input reactance to give you the
volts.

The lower the frequency, the smaller the radiation resistance, the higher
the reactance and the higher the volts.
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Reg, G4FGQ