"Reg Edwards" wrote in message
...

"I assume you measure SWR only to estimate antenna bandwidth. At the
other end of 55 feet of coax anything can happen to SWR. But if
bandwidth decreases as the number of radials increases then at least
it is going in the right direction. I don't think you will squeeze any
other information out of it."

Boy, Reg, that last sentence describes EXACTLY what I have been attempting
to do, squeeze the last bit of information or inference that I can make of
the data collected. Your formula works perfectly for me, giving the same
results on this fancy new calculator. It is formula based (which I am not
used to), so the data entry is backwards from what I'm used to (RPN). Once I
entered your formula into the calculator just as you show it, left to right,
it produced the expected 25.4 ohms. That is one handy formula indeed! Who
knows the boundary limits for its accuracy, (only the creator would know
that), but in the case of my particular antenna, it is right on the money
and agrees with the "book" based graph that gave me the original value of 25
ohms for a 0.16 wavelength high quarter wave inverted L. It's nice to have
convergence!

....hasan, N0AN