Ham Radio Help Desk

Type “J-Pole” into any search engine and you will see dozens of not hundreds plans to build your very own J-Pole antenna. Many are variations on the tried and true 1/2 wave design with the 1/4 wave stub at the bottom. Be it a plumber’s delight with copper pipe or ladder line heaven using a trimmed up 450 ohm feed line, many folks have successfully created their own J-Pole antenna with a surprising variety of materials.

However, there appears to be some kind of mystical attraction to the 5/8 wave radiator. Several of the J-Pole designs attempt to make the radiator 5/8 wave in length and adjust the phasing stub to make for a good match.

Let’s compare the two approaches using the models available from the late Larry Cebik’s NEC collection. Here are the contenders each using 3/8 inch diameter copper pipe…
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While planning for a ham radio hike into the mountains to support the Appalachian Trail Golden Packet exercise, I asked my club members for ideas about a good portable 2 meter antenna.

One response included a link to this web page showcasing a collinear J-Pole antenna using two 5/8ths wave antenna elements.
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A friend of mine is preparing for the upcoming Virginia QSO Party in March 2009. Part of the preparations include a focus on some good VHF antennas to support the heavy use of VHF mobile operations in this party. Vertical polarization is key to success. He spoke of a 5/4 Wave Antenna.

Unfortunately, one web site promoting a 5/4 wave antenna solution failed to realize you can’t make an antenna longer without eventually hitting a limit.
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