KB9VBR 2 meter J-Pole Antenna
Welcome, I’m glad you found my site. A full line of J-Pole antennas for VHF and UHF communications are available for sale here.
I can start to say what a J-Pole antenna is not. It’s not a 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 marvellously.
The modern J-Pole is derived from an antenna called the end-fed Zep. It’s 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 modern J-Pole antenna is much shorter and optimized for VHF and UHF communication.
The J-Pole antenna can be best described as a ½ wave section over a ¼ wave vertical with a ¼ wave matching stub. The 2 quarter wave sections at the base of the antenna 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. No special grounding or a groundplane is necessary for operation.
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 plans in 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.
Sincerely,
Michael Martens
KB9VBR
The antenna I’m holding was featured in the January, 2006 issue of Popular Communications Magazine!
Page 53, here’s an excerpt from the article:
Connecting the coax to my Yaesu VX-6R, I tuned around and found an active repeater. During a lull, I put my callsign out and received an immediate reply. Imagine my surprise when I was told that the repeater was on Catalina Island- 69 miles away from my location. Not bad!
-Laura Q – KI6AOK
