Ham Radio antenna design

On most of the J Pole designs out there, a choke should be used as close to the feedpoint of the antenna as possible to help prevent rf on the feedline and creating difficulty with SWR readings. For 2 meters, the coil is 4 turns of coax at 5 inches in diameter. You should get good results with the choke within 3 or 4 inches of the feedpoint on 2 meters.

Hint:
Use the last part of your feedline as the choke before attaching to the feedpoint!

Hints from builders:

"Iv'e built my j-poles out of 10ft sticks of 1/2" emt conduit. Drill a 1/4" hole at the place where the "J" goes. Make the "j"out of 1/4" soft copper, Solder it in place thru the hole and add the cable. Cost about $6 using new parts.
If you need a "super" j, use a piece of 3/4" pvc as the insulator and add the stub and another 38 or so inches of conduit. still really cheap".
Dave, WB5HDS

Convert a J Pole to a Slim Jim
More Antenna Projects!

DANGER!
Do not install ANY antenna over, under or near power lines!
HAVE FUN...NOT A FUNERAL!

J Pole Calculator and drawing used on this page are
Copyrighted by
K4ABT G. E. "Buck" Rogers Sr
k4abt@packetradio.com
www.buxcomm.com
www.PacketRadio.com
See his articles in back copies of CQ Magazine
(The Packet Users Notebook)
Copyright 1996
All rights reserved

Portions of this page copyright Hamuniverse.com

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