"JIMMIE" wrote in message
oups.com...
Plan is to build a J antenna for 20 meters using 1 inch EMT conduit.
Antenna will be supported at the bottom by a 4x4 post in the ground and
at the 30+ foot level with a fiberglass bracket bolted to the eve of
the house. The upper most section will be a fiberglass 1/2 wl antenna
thta used to be used for CB. I am looking for a program that will allow
me to calculate deminsions for a project like this. Feedline will be 50
ohm coax.

Why not build an end fed 1/2 wave antenna and forget about the mechanics of
the 1/4 wave matching section and the problems of its height? IMHO, a simple
L or Pi network in a WX proof box with a 33' vertical would be a lot easier
to construct and adjust than a 50' tall antenna.

Dale