hi fred, thanks for your input, if i read you correctly this is cut for 2mtr
and the one i'm working on is actually a marine vhf, (usually I think cut
for 156.8mHz), i realise this is a ham group but hoped it would be ok to ask
here.

i have found some online calculators, maybe i can use the information from
them to recut this design.

thanks fred

kevin

"Fred McKenzie" wrote in message
...
In article , "kevin"
wrote:

hi there, i'm looking for some help with a j pole antenna, it's actually
a
vhf marine antenna so i hope it will be ok to ask here.

Kevin-

One version of the J-Pole antenna has the cable connected an inch or two
above the connection between the two vertical rods. The following article
from my archives, shows how it could be connected, except it is based on
Television Twin Lead instead of the two rods yours has. If you use a
mono-spaced font like Courier, it should be clear. The conductor above
the 1/4" gap is not essential, it just comes with the twinlead!

Fred

---------------
2M Jpole with 300 ohm twin lead
From: (Andrew A. Kinsman)
Newsgroups: rec.ham-radio
Organization: Eastman Kodak, Dept. 47, Rochester NY

The following is a description of a J-Pole antenna made from 300 ohm
TV twin-lead. Quite a few of the hams in the area have successfully
built one or more of these antennas. They have quite a few advantages
which include improved performance for 2-meter HTs, portability, and
last, but never least, they are inexpensive.

| | do not short this end.
| |
| |
| |
| |
| |
54" | |
| |
| |
| |
| 1/4" gap
| |
| |
| | 16 3/4"
coax ctr conductor=* *= coax shield
| |
1 1/4" | |
-*-
solder the twin leads together at bottom

1. Start with 54 1/2" of TV twin lead (foam core does not work as well)
2. Strip 1/2" of insulation at bottom and solder wires together.
3. Measure 1 1/4" from soldered wires and strip insulation on both
sides. This is the solder point for a coax feedline.
4. Measure 16 3/4" from bottom and cut out 1/4" notch on one side.
5. Feed with a length of RG58U coax. Tape coax at feedpoint to the
twin lead for strength and weather protection.

I have also attached an alligator clip to the plastic on the top of
the antenna in order to conveniently hang it. I am successfully using
one in my attic to avoid any CCNR problems. I have another that I can
take with me camping, sailing, etc.

This design has appeared on many BBSs and in club newsletters; the
earliest reference that I know of is a Jan. 1984 D.A.R.C. antenna
article by James Burks, KA5QYV.

Enjoy,
N6UBM
------------------