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

Don't want to build but rather buy? Get a 2m/440 dual band J Pole from Amateur Radio Supply...click the picture below for more info!

Click picture for more info!
Made in the U.S.A. from solid aluminum! Very heavy duty and built to last!

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

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

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