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Running Radials the Easy Way -- Sew What?

Created by Ron Bean, KJ5XX on 2023-04-10

"Editor's Note: Due to the popularity of some of eHam's older articles, many of which you may not have read, the eHam.net team has decided to rerun some of the best articles that we have received since eHam's inception. These articles will be reprinted to add to the quality of eHam's content and in a show of appreciation to the authors of these articles." This article was originally published on: 11/02/2009

 

Running Radials the Easy Way -- Sew What?

In the process of building a stealthy vertical antenna system recently, I was thinking about how best to install an efficient radial system on my city-sized lot.

It occurred to me that other than not wanting to run over the radials with the lawnmower, that there really wasn't a real need to "bury" the radials at all.

I came up with the idea of "sewing" the radials just below the surface of the grass. The next question was finding a suitable sewing needle that was up to the task.

The solution I came up with was to use a stainless steel whip from an old Bugcatcher antenna that I was no longer using. The whip was about 4' in length and provided a nice flexible, yet thin and sturdy platform that turned out to be just perfect for threading my radial system.

Of course a longer whip would be even better, and would prevent having to pull the needle through and reinsert it again.

To use this method, I did the following:

1. Cut your radials. My antenna was designed to operate on 40, 20, 15 and 10 meters, so I cut sets of radials for each of these bands. It helps to have one wire color for each band you plan to operate on. This isn't a requirement, but makes running the wires easier as we'll see in a moment, if you plan on laying your radials in "sets".

2. Using "marking paint" (found in local hardware stores in bright orange or red, but any can of spray in a color that is easily seen will work), I marked the distance from my antenna to the place in the grass that each length of radial would terminate at, so measuring out from the radial, I made spray marks in my lawn at the termination point for a 40m, 20m, 15m, and 10m radials, and I repeated this process for each "set" of radials that I ran.

3. Drive a stake in the ground at the point where your radial system will attach to your antenna base. Leave an inch or so extra on the end of each radial to be sure that you have what you need for your solder lugs or whatever you are planning to use to attach the radials to the base of your antenna. Attach your radials to the stake. This will serve as a temporary anchor point while you run the radials.

4. Using electrical tape (duct tape will also work well), tape the other end of your radial set to your needle. There is no need to wrap multiple layers of tape. Just tape the radials to your needle so that they are secure, but not too tight.

5. Keeping the needle parallel to your lawn and close to the surface, thread the tip of the needle just beneath the surface of the grass. You'll be able to feel when you are going too deep - just pull the needle back out an inch or so and re-thread. You'll also be able to "see" your needle as it makes progress, as it will cause the grass to sort of push up as it tunnels its way through. If you run out of "needle" before you reach your spraypaint mark, simply re-insert it near its point of exit and go again, just as if you were sewing.

6. When you approach your first spraypaint mark, push the end of the needle up close to that mark, then feel for the needle and extract the tip. Then pull the rest of the needle through and out of the grass. Pull until the needle just comes out of the grass. If you measured correctly, your shortest radial should be taught and line up with your paint mark.

7. Having identified your shortest radial, pull it free from the needle. If you used a different colored wire for each band, this will be very easy to identify.

8. Now, take the portion of the radial you just pulled free from the needle and push it underneath your grass. If you need to, you can use a box cutter to make a slit in the grass and re-insert the radial end.

9. Now, this next part can be a little tricky. Pull the slack from the remaining radials until you feel tension on the shortest radial. Now, re-insert the needle, as close to the point where it exits the grass as possible, and start threading again. This is where the flex in your stainless whip will come in handy, because you may have to use this flex to give you some extra room to allow you to re-insert the tip. Work with it, if you don't get it on the first try - like I said, this is the tricky part.

10. Repeat this process until you have all of your radials laid.

As an alternative, you can lay the radials one at a time as opposed to laying them in sets. You may find this faster depending on what bands you plan on using (and therefore, how close the radials are in length to one another - this is kind of hard to explain, but if the lengths are close and you lay them in sets, it can make it hard to extract the needle and re-insert it).

That's it!

I'd be interested in hearing from other hams that have tried this method, and have any suggestions for improving it (or the instructions I've laid out here).

 

N5XJT2023-04-15
Re: Running Radials the Easy Way -- Sew What?
For my vertical I ran 27 radials varying in length from 12 ft. to 55 ft. due to a narrow lot. I simply mowed the grass low, using metal landscape staples starting 3-4 inches from the radial plate and about every 7-8 ft. thereafter stapled them over the grass. Withing two weeks the grass had covered all. That was 6 yrs. ago and still working fine with no issues.
Reply to a comment by : KL7CW on 2023-04-11

I have about 40 90 foot long radials for my 80/160 vertical. That is over a half mile of wire !. Many of these wires are mostly in the woods with trees and much brush. With all the roots and rocks, I did not want to bury it the whole way, but I used a similar method with various probes between 6 and 8 feet in length. In some areas this method worked great, and even sometimes I used a bent needle to go under shallow roots. Probably well over 1000 feet buried this way. Moose, and occasionally other animals or humans walk in the woods, so the radials are somewhat protected. Rick KL7CW
KL7CW2023-04-12
Re: Running Radials the Easy Way -- Sew What?
The Battle Creek 160/80 meter antenna used by many DXpeditions in the past was well researched. Their radial field was something like 40 seventy foot radials laying on the ground. It also was a compromise, but the predicted and realized performance was probably very close to a much larger radial field. This is one reason why I chose the new radial field I put in. It also used up the wire I had and I did not want to spend all of our short summer crawling around on the ground for possibly a very small gain. If 80 was my main interest, then shorter radials would be just fine. Rick KL7CW
Reply to a comment by : KL7CW on 2023-04-11

I have about 40 90 foot long radials for my 80/160 vertical. That is over a half mile of wire !. Many of these wires are mostly in the woods with trees and much brush. With all the roots and rocks, I did not want to bury it the whole way, but I used a similar method with various probes between 6 and 8 feet in length. In some areas this method worked great, and even sometimes I used a bent needle to go under shallow roots. Probably well over 1000 feet buried this way. Moose, and occasionally other animals or humans walk in the woods, so the radials are somewhat protected. Rick KL7CW
KD6VXI2023-04-12
Running Radials the Easy Way -- Sew What?
A couple things in this article. Some matter, some not so much.

Cutting radials for each band is a waste of wire when using buried radials. When you have a raised radial system (ground plane anyone), the radials are tuned to give return currents a path. Tuned radials = more current = more better.

Untuned radials are needed when putting them in or on ground.... Or just above ground a non appreciable wavelength (I believe Severn's said you need to be at least .1 or .15 wavelength above ground to be considered "appreciable"). When putting radials down for a ground mounted vertical the radials are there to screen the RF currents from the lossy ground. You want Rground to be as low as possible to minimize losses to heating worms.

Someone else said that only X amount of radials is needed, and anything more was a waste of wire.

That is also incorrect.

Severn's as well as others have found that for a given amount of wire, it is best to have more radials on the ground rather than longer radials on the ground.

If you have 1000 feet of wire, it's better to have 36 x 27 foot radials rather than 4 x 250 foot radials. This is to act like a screen and shield the antenna near field from coupling to the earth.

Otherwise, great idea. Too bad I live on a rock now. When I lived in the states, this would have been a great idea!!!


--Shane
WP2ASS / ex KD6VXI
KL7CW2023-04-12
Re: Running Radials the Easy Way -- Sew What?
My previous radial field for 40 years was probably something like 20 radials perhaps 45 feet long. It worked fine on 80 and 160, even though through the years some radials were snagged by snowplows, backhoes used for construction and a new septic system. I saw a big reel of wire at a box store for fire sale prices, so bought the thing, which supplied most of the wire for my big radial field about 5 years ago. When I did modeling decades ago the software could not do a good job with buried radials. However for sure the radials do not need to be a quarter wave long since on ground or buried radials are not resonant. One rule of thumb (which could be wrong) is that ideally the radials should be at least as long as the tower is high. I put in a radial about each 10 degrees, since I thought that through the years I might lose a few. A quarter wave on 160 meters is about 130 feet, thus I thought a 90 foot radial would be adequate for my 60 foot high tower. Since I had the wire and have the energy, I thought my radial field would be fine with my energy level and budget. For sure, probably half of my new radial field could have been left out with only a very small additional loss of probably less than or much less than one dB. If I were doing it again, would probably just use an elevated radial field away from the house a few hundred feet away. I think for buried radials, the original author could have just used radials all the same length, perhaps somewhat shorter than a quarter wave on the lowest frequency band. Rick KL7CW
Reply to a comment by : K4LIX on 2023-04-11

I've seen this stated before so I am NOT the originator, but I will repeat it here: Any wire underground radials longer than about 20 feet is a waste of wire. About 16 - 20 foot radials, spaced about 20 degrees apart will make a fine radial system for just about any vertical. NOW, if you're going to elevate the radials ABOVE ground, that's a different story - you have to go by formula calculated lengths. So...
Reply to a comment by : KL7CW on 2023-04-11

I have about 40 90 foot long radials for my 80/160 vertical. That is over a half mile of wire !. Many of these wires are mostly in the woods with trees and much brush. With all the roots and rocks, I did not want to bury it the whole way, but I used a similar method with various probes between 6 and 8 feet in length. In some areas this method worked great, and even sometimes I used a bent needle to go under shallow roots. Probably well over 1000 feet buried this way. Moose, and occasionally other animals or humans walk in the woods, so the radials are somewhat protected. Rick KL7CW
K4LIX2023-04-11
Re: Running Radials the Easy Way -- Sew What?
I've seen this stated before so I am NOT the originator, but I will repeat it here: Any wire underground radials longer than about 20 feet is a waste of wire. About 16 - 20 foot radials, spaced about 20 degrees apart will make a fine radial system for just about any vertical. NOW, if you're going to elevate the radials ABOVE ground, that's a different story - you have to go by formula calculated lengths. So...
Reply to a comment by : KL7CW on 2023-04-11

I have about 40 90 foot long radials for my 80/160 vertical. That is over a half mile of wire !. Many of these wires are mostly in the woods with trees and much brush. With all the roots and rocks, I did not want to bury it the whole way, but I used a similar method with various probes between 6 and 8 feet in length. In some areas this method worked great, and even sometimes I used a bent needle to go under shallow roots. Probably well over 1000 feet buried this way. Moose, and occasionally other animals or humans walk in the woods, so the radials are somewhat protected. Rick KL7CW
KL7CW2023-04-11
Running Radials the Easy Way -- Sew What?
I have about 40 90 foot long radials for my 80/160 vertical. That is over a half mile of wire !. Many of these wires are mostly in the woods with trees and much brush. With all the roots and rocks, I did not want to bury it the whole way, but I used a similar method with various probes between 6 and 8 feet in length. In some areas this method worked great, and even sometimes I used a bent needle to go under shallow roots. Probably well over 1000 feet buried this way. Moose, and occasionally other animals or humans walk in the woods, so the radials are somewhat protected. Rick KL7CW