Choke balun 1:1 to 40m with RG-174 coax.

I read about ugly and choke baluns on the Internet, but could not find the solution to my case. I have an dipole antenna for 40m (10.10m awg 26 wire to each side) and would like to try a choke balun for that using the RG174 coax.
Anybody has the formula I should use to find the right size of coax should be wrapped on a 1" pvc tube?
Tks and 73, PY1II

See the detailed description here:

Probably lighter and more efficient than an “ugly” one.

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Hi Douglas,
Firstly, why do you need a balun? If the feedline is deployed close to a right angle to the antenna then common mode currents should not be a problem.

You will need something like 25 uH for reasonable choking impedance . On a small former like the one you propose I think you will need 70 turns. That should fix any common mode problem.

Most air baluns used on HF have a bigger diameter. 300 mm or so with 6 to 10 turns held by cable ties.


To tame a problem I had on a 30m dipole I use a 5 or 6 turn 13cm diameter coil “perfect wound” and held in shape with insulating tape. This is mounted just below the feed point.

See: Do I need a balun?