Bart Bailey wrote:
I'm thinking of trying a 5BTV on a 30 foot pole with one good
counterpoise about two thirds way up and a good earth stake ground at
the bottom. I don't have room for an array of radials in all directions
but am hoping the solitary long one at the twenty foot level will allow
the thing to tune. Are the multiple fanned out radials really necessary
to get resonance, or aren't they just to create a more uniform pattern?
The one long counterpoise is several hundred feet long.

At least three symmetrical radials are required for a
close to omnidirectional pattern when the radials are
elevated by an appreciable amount. The horizontal radiation
from symmetrical radials tends to cancel due to destructive
interference thus adding constructive interference to the
vertical radiation pattern. So the gain and efficiency are
also affected. Resonance may not be the only consideration.
--
73, Cecil http://www.qsl.net/w5dxp