Jimmie D wrote:
Been cleaning out the garage this weekend and came across an old attempt at
build a 432Mhz helix antenna. As I remember I gave up on it because I was
having trouble building the matching section which was a 11/4wl long fin
that attches to the helix as it apprached the feed point. It was proving
difficult for me to fabricate. I was wondering if the fin could not be
attached to the counterpoise instead of the helix, adjusting the space
beteen the fin and the helix to get a match.

I've always had success matching a helix by running the first 1/4 turn
(starting at the feed point) parallel to the reflector and changing the
spacing between the 1/4 turn and the reflector until I get a low SWR.
If the reflector is mesh I put a piece of sheet metal on the mesh under
that 1/4 turn. It's worked every time, no fins, no 1/4 wave sections of
coax, etc. For my 432 MHz helix it ended up with about 1/4 inch
spacing, using #10 solid wire for the helix.

-W8LNA