The AM Forum

Anybody have any idea about how high the voltage would be at the endpoints of a resonant ant? Let stay running at 1KW CW.

Thanks,
-Bill 'GF

Ohm's law will calculate.  P=E(squared) over R or P=.IE

If its at the end half wave dipole, theoretically the RF current is 0, so the voltage is P/I or very high.   Thats a good question, what would it be in reality?   I suppose a few thousand volts RF.

enough to light dry oak leaves in the fall.
They turn brown when they are green.

Thanks, I knew it was high. But I thought that maybe somebody had a computer model or formulas...

-Bill 'GF

Once there was a bunch of guys walking through the back yard and I had an inverted V. I saw them heading for the antenna so keyed up 100 watts just as one of them grabbed the wire. I figure the voltage was pretty high by the yell of RF burn pain.

gud one....   although, I think that Garys "man eating antenna" is a better story.... 

Bill,

I think you are looking for "boundary conditions" as related to discharge of end insulators on antennas, or self supported elements, for that matter.  Much has to do with the dielectric and breakdown voltage of the surrounding air.

The subject is mentioned in the Antenna Handbook but does not go into formulas.


But here is a paper on the general subject that has theory and formulas. Pull out some of the phrases related to "boundary" and do a Google further.

http://prst-ab.aps.org/onecol/PRSTAB/v8/i5/e050401

73,
T

Say you have 1000 volts peak to peak at the feed point of 50 ohms. Say the end Z is 5000 ohms. I suppose an Mr. Ant Vu says it is all in the leakage.