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New to Ham and POTA - How Many Counterpoise Radials?


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I am new to Ham Radio and have activated 15 Parks on the Air locations in NJ. My question is what is the correct number of counterpoise radials to use with a temporary .4 wave or 1/2 wave vertical antenna? I typically only use 4 radials to keep the set up time down. You can see an example of my last POTA activation here.

Thanks for the Help

Scott AA2SD

Edited by K3MRI
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Hi Scott and welcome to Ham Community.

Asking advice on radials is almost like asking Santa for a gift... you never know what you get. Kidding aside, the discussion on radials is over a Century in the making and the opinions differ wildly, which one would think is bizarre considering it's physics and there should only be a right or wrong.

Also, if I may correct you, there is technically a difference between a counterpoise and a ground radial. One is intended to create a 'ground' the other is intended to lengthen the electrical length of the antenna. For now, let's talk about radials.

Also, we're talking POTA which also means portability and ease-of-setup.

First I'll tell you my theory/approach. Too few radials are useless, too many interfere with eachothers' electrical fields reducing each other's usefulness/effect. My personal choice, if I do use a radial in the field, is to create a circle that is then connected to the antenna ground with just four radial wires. I have my own copper 'ring' that I set to one-quarter wavelength of the band I'm on. Oh, right, did I mention that the radial is in proportion to the band, not the antenna length. You're grounding a wave of a given length, not a stick, per se. That also means that you have to, in theory, have different rings. Same applies with traditional radials, btw. If you're setting up an AM commercial radio antenna tower it's easy... always the same frequency. If you're a ham, you're all over the place.

If you look at what Alpha Antenna does, and they sell a great vertical that I use - the FMJ - they just provide a single ground wire. I have made a 7000 miles DX contact with 5 watts!

You'll notice that so far I have not really delved into the physics. I could, but I won't because I think you're better off finding a perfect location, ideally one that has soil with good conductivity, and yes, maybe using four ¼ wavelength radials. Trust me, that soil is what will make the most difference. We've done tests in one location while on the asphalt and another 20 yards away on a salty, marshy soil and the difference was insane.

Not sure if I rambled too much and if I was even helpful, but there you have it, don't ask Santa for a gift 🎅

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  • K3MRI changed the title to New to Ham and POTA - How Many Counterpoise Radials?

Thank you so much for this explanation I have been using 4 matched to the antenna length with very good success.  I have been told 24 or more which is not practical for a quick POTA set up.


I won't ask Santa for the radial gift 🎁!








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  • 4 weeks later...
  • Elmer

There was a series of articles in QEX exploring the practical advantages of increasing the number of radials for a vertical antenna. In fact, more is better given a properly erected vertical antenna above ground. The interesting result is that your propagation is best along the lines of the radials. For example, 4 radials N, S, E and W will maximize performance in those cardinal directions. NW, SE, SW and SE will suffer a little. Curiously, if barriers prevent you from a radial in one direction, only that direction will be at a disadvantage. Perhaps the largest problem with using a vertical at many frequencies is the impedance of the feedpoint. If I recall correctly, a 1/4 wave vertical tends to have a low Z. I assume the grounding system impacts the impedance. 

A vertical antenna can have some disadvantages for POTA. It has a low take-off angle, so nearby (taller) mountains can be more of a problem. Also, trees in wooded areas are more of an attenuator for ground-mounted (vertically polarized) antennas, compared to something like a dipole. An advantage of a vertical antenna over a dipole is that a dipole on a low band (e.g., 40m or 80m) will become a NVIS antenna if too close to the ground. NVIS is good for local communications but is lousy for long distance skip.


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