Looks perfectly reasonable to me, Jim. Another perfectly reasonable thing to
ask is "what is the electric field strength near the antenna elements?" because
if the field strength is too great, you can get corona. And EZNEC (NEC2, etc)
will give you at least an estimate of that value. As you say, it can be
interesting to know if an insulator will be adequate, and that's a question
well worth asking.

Cheers,
Tom


Jim, K7JEB, wrote:

Well, I chose one particular configuration
and one particular integration path because
I was curious about the original question -
something about how much voltage would the
end insulator have to handle for 100 watts
of radiated power.

I chose a vertical, half-wave monopole fed
against perfect ground and looked at the
driving source data with EZNEC. The feed-
point impedance was 2188 +j66 ohms and a
driving current of .213 amps produced a
radiated power of 100 watts and a feedpoint
voltage of 466 volts. 1500 watts scales
that up to 1805 volts. Symmetry about the
ground would increase that to 3600 volts
for the free-space case. That is what I
would adopt as my design-to target for
end insulators.

I know it's crude, but I was just looking
for a ballpark figure.