I recently purchased the Gabil GRA-7350T antenna and the GRA-GNT Antenna Mount. However, this didn’t include ground radials with it. So, I set out to make my own. I quickly came up with a few questions. in addition to how long should they be.

  1. What gauge should they be.
  2. Do I need heavier gauge when using more power
  3. What type of insulation is best.
  4. how many radials do I need.

So, the video below did answer a few of those questions.

  1. The video below explains how to calculate the gauge wire you need. In his example. Dave was figuring transmitting at 800W and based on the number of radials. Dave determined the wire would need to handle about 4 amps at 800w.which led him to choose 14-16 gauge would fit his purpose.
  2. Yes, according to Dave you do need thicker wire (lower gauge number) to handle more power.

Dave also has some tricks for laying the ground radial if you are doing a more permanent install. He actually recommends using a pizza cutter. To install them in your lawn. (Watch the video)

So, on to what I decided I need to do for my specific use case. Which I guess I should explain that before we go any further. I intend to use my setup while doing POTA (Parks on the Air). This means i want my setup light wight and very portable and durable. Which should be evident from my choice of the antenna and mount I’m using. I do a lot of camping and hiking. Eventually i would like to get into some SOTA (Summits on the air). This goal obviously plays a role in my choice of gear.

My objective was to keep the radial system as light weight and compact as possible. Since I was at most going to be transmitting at only 100w I didn’t need the larger gauge wire. What I went with was a 24-gauge silicone insulated wire. This should be fine got my needs. I’m planning 4 radials cut for 20 meters. (NOTE: I didn’t do the math. I hate math) I will probably cut additional sets in a different colors for 10 and 40 meters. But first I will try seeing how radials set for 20 meters work for 10 and 40 meters. I also believe you can fold the radial over to shorten them for say 10 meters.

I choose the silicone insulated wire because it its usually more flexible than other types. This hopefully will make it easier to spool up when done.

As for how many radials needed. I don’t have an answer many usually just use one. but that can make the antenna directional. So, i will be starting with 4. Will see how that works.

Make sure you watch David Casler’s video above as he does a great job of covering this material.

PS: I did have Copilot do the calculations. It calculated 1.41 amps. 

Basic Calculation
Assuming a perfectly matched system (50-ohm impedance):
Power (P) = 100 watts
Impedance (Z) = 50 ohms
Current (I) = √(P / Z) = √(100 / 50) = √2 ≈ 1.41 amps RMS

Across 4 radials it's down to .35 amps.

Found this out in my conversation with copilot. thinner gauges might increase the resistance. Copilot actually specified 18 awg wire. But when prompted explaining weight of the wire was a factor in the choice it recommended 20 AWG. And without my mentioning SOTA or POTA this was it’s reply

If you’re going portable (like for POTA or SOTA), go with 20 AWG stranded copper or even lightweight speaker wire—easy to pack, deploy, and replace if needed. For home installations, 18 AWG gives you peace of mind without adding much weight.

So next time before I order something I’m going to consult Copilot. I’ll let you know how my 24 awg wire works out. Incidentally fellow hams recommended 20 awg. (But I always have to be different)

Special thanks to Dave Casler for creating a great video. Please check out his other videos.

Discover more from KC2ZQO

Subscribe to get the latest posts sent to your email.