JIMMIE wrote:
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.

You don't need a program. The long element is 3/4 wavelength long. The
shorter parallel element is 1/4 wavelength long. You can short the
two elements together at the bottom and attach your feedline at the
50 ohm point on the two parallel elements. Or you can feed the long
element with the center conductor and the short element with the
braid of the coax. 3/4 wavelength on 20m is about 50 ft.

The free demo version of EZNEC from www.eznec.com will probably model
that antenna.
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73, Cecil http://www.qsl.net/w5dxp