Tune Around!

CQ-Calling All Hams!
About Hamuniverse
Antenna Design
Antenna Safety!
Ask Elmer

About Batteries
Code Practice
Computer Help
FCC Information
Ham Hints 
Ham Radio News!
Post Reviews 
Product Reviews
Ham Radio Videos!
HF & Shortwave

License Study
Midi Music
Reading Room
Repeater Basics
Repeater Builders
RFI Tips and Tricks
Ham Satellites
Shortwave Listening
Support The Site
Vhf and Up
Site Map
Privacy Policy
Legal Stuff

Advertising Info

 The CB-whip 2/440 HAM "J" Antenna

by N6JSX June, 2012

Here is my very successful 2m/440 dual-band single-feed "J" mobile antenna made with a 102" CB whip.

I've been using this J for more than 25yrs on my mobiles. Over the years through trial-n-error I've modified my basic design making the J more effective and very durable.

In general a VHF/UHF "J" :

has a low, almost flat angle of radiation, for maximum distance,

no ground-plane or radials required,

relatively easy to make and durable!


The "J" is the BEST antenna for flat-lander's giving them the longest transmitted signal distance possible. This is due to the exceptional low main lobe, nearly flat, angle of radiation of about 1-3 degrees.

The more common antennas have much higher radiation angles that may be good for mountain top repeaters but will significantly shorten flat-land distances. The 5/8 wave has ~3-6 degree radiation angle with the highest angle of ~4-9 degrees is from a ¼ wave. These ¼ wave & 5/8 wave antennas require a good counterpoise for optimal omini-directional performance.

The "J" has approximately 3dB of gain over a 1/4 wave ground plane. Technically, the "J" antenna is an end-fed 1/2 wave antenna using a 1/4 wave matching stub. In years past it was referred to as an "end-fed Zepp". The matching section acts as a matching transformer, the 1/2 wave radiator sees the 1/4 wave matching section as an image of a false ground. In best terms, the "J" is a balanced 1/4 wave matching stub feeding an unbalanced 1/2 wave load. The long element is 3/4 wave with a 1/4 wave matching element creating a tuned 1/2 wave active radiator that needs no counterpoise (ground plane/radials).

Download and save the entire construction details here to see how I built it.
Pdf file. Adobe Reader required!

If you had rather buy than build, see the Arrow 2/440 J Pole here!







Hamuniverse.com uses Green Geeks Web Hosting!