DBJ-UHF $50 - 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.
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)