KB9VBR J-pole Antennas

Please go to www.jpole-antenna.com to purchase my antennas.

I can start to say what a J-Pole antenna is not. Its not fancy antenna with lots of radials, stubs, or traps. Its also not a magic ’super gainer’ antenna that will let the world hear you with 5 watts of power. The J-Pole is quite simply an antenna that works marvelously.

The modern J-Pole is dervied from an antenna called the end-fed Zep. It is similar in design to the end-fed antennas of the 1930’s; most notably the antennas used on the Zeppelin dirigibles. Of course the Zeps used on dirigibles where long wire HF antennas that trailed out the rear of the cabin. The J-Pole is much shorter and optimized for VHF and UHF communication.

The J-Pole antenna can be best described as a ½ wave over a ¼wave vertical with a ¼ wave matching stub. The 2 quarter wave sections run parallel to each other. The current in the one section will be out of phase of the other, keeping that section of the antenna from radiating. The remaining half wave section will radiate extremely well since there is no counteracting field to keep it from radiating.

As a half wave antenna, the J-Pole doesn’t need any radials or a ground plane to work. Average gain with a 2 meter J-Pole is about 3 db. Many like to compare the gain and antenna pattern to that of a Ringo Ranger. The biggest advantage of the J-Pole is that it is at DC ground, so it can be mounted just about anywhere and still work.

You can build your own J-Pole, construction is straightforward. All you need for tools is a pipe cutter or hacksaw and a propane torch. I have detailed construction plansin this Adobe Acrobat document.

I also have a full line of J-Pole antennas for sale. I sell models ranging in frequency from 50MHz up to 470MHz. Check out my products page for full details and price.