"Bob D." wrote in message
...
I decided to install a 2m FM rig in my garage to stay in touch with the
local repeaters while working on the car. I want a quick and dirty
homebrew
antenna at the roof line. I know the J-pole is a popular 2m antenna, but
why??? The J-pole is basically a half wave antenna fed at the end, right?
At
2m you are only 19 inches away from the 50 ohm feed point (a classic
dipole), so why not just loop the coax into the middle and forget the
matching stub? Am I missing something?

If I do this, would a clip on ferrite at the feed point make a good
choke-balun?

--
Bob D. ND9B

The coax must depart perpendicular from the 75 ohm feed point by .2 to .5
wavelength or greater for the Vertical dipole you describe. This makes it a
great tower side mount antenna with gain like a 2 element beam. When
mounted this way, the coax gets dressed down the tower leg and all is well
without ferrites.

J-pole is simple to build with 300 ohm TV twinnlead that was once cheap and
available anywhere. Also the J-pole includes a matching section to 50 ohms
.. Hang up one by a string, and roll it up for travel. Light weight and
slick. Vertical dipole needs something like a gamma match to get to 50
ohms, but 75 ohms isn't far off and the antenna is fairly broad too. A
variation is the coaxial dipole, that feeds the coax up a 1/2 wave mounting
pipe to the feedpoint and a 1/4 wave whip and larger 1/4 wave ground skirt.