DBJ-UHF  - Perfect for GMRS - published in CQ - summer 2010 - US patented 8,947,313

This antenna was first presented at Pacificon 2010.  It was based on a grant given to us by AC Daughty Inc.  in 2010.   An article on this antenna was subsequently published in  CQ - Summer Addition 2012.  It has been granted US patent 8,947,313.   This is a unique design which met the requirements of AC Daughty Inc.   Some of the features include 5dB gain, only 3 1/2  ft tall, no radials, up to 150 MPH winds. AC Daughty Inc.  uses over 200 of these antennas in a MESH network in New York.   

Basic  Specifications:

Overall Length: 3 1/2  feet, 50 ohm feed impedance, no ground radials.  Antenna feedpoint is 10 inches above the connector.  Thus U clamps, hose clamps, etc. can be used for mounting up to the first 10 inches of the antenna without affecting performance.  Antenna offers “true” 2 element  ½ wavelength phased radiator  (centered tuned).  
 
UHF   (430-470 MHz)  -  Custom tuned to GMRS specification

Configuration:  two element  ½ wavelength phase collinear separated by 1/2 wavelength
Maximum power: 75 watts
SWR:  less than 1.3 to 1 over a 5 MHz bandwidth and less than 1.5 :1 over 10 MHz bandwidth.
Matching system:  1/4 wave matching stub, ½ wavelength phasing stub
Gain:  5 dB over reference ground plane
Impedance: 50 ohms

REQUIRES 3.5ft of 3/4 inch thinwall pipe (available at Lowes) Orange Tag