J-Pole Antenna Length Calculator

Enter your target frequency: MHz  

The calculated J-Pole measurements for 146 MHz are:

Long Side Short Side Feed Point Spacing
A B C D
4.829 ft 1.603 ft 0.158 ft 0.151 ft
57.945 in 19.233 in 1.89 in 1.808 in
1.472 M 0.489 M 0.048 M 0.046 M
1471.8 mm 488.5 mm 48 mm 45.9 mm

12 thoughts on “J Pole Antenna Length Calculator”

  1. Could I use a copper strap with 1/2 clamps on both sides that can be loosened to tweek up an down j pole. I would mount the SO-239 to the strap an braze a pcs of copper from the SO-239 to the copper strap.

    1. If I’m following you correctly, I believe your idea should work well. Be sure to braze it permanently in place once you find your “sweet spot”, otherwise you may have corrosion problems in the future. Good luck!

  2. Thanks for this very helpful material. I have a question: Where should be the center of the Coax be installed? Longside or Shortside.

    1. Depending on who you ask or where you look, some say it doesn’t matter. But I attach the coax center to the long side – it’s always worked very well for me.

  3. I want to make a Jpole antenna for the 222MHz band! There are lots of antennas for all the bands but have not seen anything for this band. There must be some but not found them. I am disabled retired living off SS. That makes Ham radio hard to use. I am hoping to be able to make an antenna for the 222MHz band to use with my new Anytone D578 radio. Thank you for any help you can give me.

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