Topband: Gamma matching crank-up tower

George & Marijke Guerin
Fri, 25 Oct 2002 06:19:31 -0400

Dear Jim et al,
    As many have commented, the cables that hang down on stand-offs make
shuntfeeding a tower difficult at best.
    Rather than sweat the details or argue about cable dressing along tower
legs please consider an inverted-L hung off the top of the tower when it is
cranked up.  A wire 80+ feet up and 80- feet out makes a nice 160 ft
inverted-L that is easily matched with a series vacuum variable capacitor of
about  450 pfd.
    One can set the feed point a few feet from the base of the crank-up
tower and use about 10 ft of rope with a sliding insulator to support the
center of the wire.  That way, no work is needed on the tower and isolating
or reworking a dipole or inverted-V antenna can be avoided.
    Good luck,    73,    George    K8GG