Discussion in 'Antennas, Feedlines, Towers & Rotors' started by AC3DB, Aug 4, 2013.
It doesn't matter, insulated or uninsulated.
However, why bother using a shovel to bury them? I never do that.
You can just lay them straight out on the ground (in the grass) and "staple" them to the ground using "lawn staples" which cost about ten cents each to hold them down tightly to the thatch.
After 3 months, they bury themselves and you'll never see them again. In the meantime, you can mow the grass right over them, because they're pulled taut to the surface below the grass.
I wouldn't spend ten seconds "burying" radials, when from experience (having done this dozens of times) I know they'll bury themselves.
What I do is pull the radials taut at the surface and terminate each radial with a cheap tent peg hammered into the ground to keep it straight and taut. Then, I use a few "lawn staples" along the length of each wire to pull it right down below the thatch. This all takes about 30 seconds per radial.
Go out in 3 months and see if you can find them.
Insulated radials are perfectly OK and will work fine. The earth is very lossy to RF currents (unless you're in a marsh), and the copper radial is what provides a lower loss path for current. An elevated radial field, although usually less practical, is even better and it is really insulated from the earth.
I agree with WIK; don't bury the radials, just lie on the ground and if you have vegetation it will cover them with a year. Don't pull too tight, you want them to lie slack on the ground. Landscaping staples, used to hold down fabric and available at Menards or HD, work well to keep the wire close to the ground so your mower won't catch.
I did exactly what you're doing with about 64 radials varying from 30'-64' and they work well. Exact length isn't important, and the more the merrier. Although there are diminishing returns past 30-40 radials.
It is important to tie the radials to a common point at the base of the antenna. I used a DX Engineering SS plate designed for this purpose, and it works well. You can homebrew something similar.
the one guy said to sew them in with the grass and it'l cover them. I was paranoid of ripping them up with the lawnmower so I buried them, only an inch. But I'm glad to hear that insulated will work ok. It seems to be working great so far this evening.
A buddy of mine did tear up his radials with a mower, months after having tacked them down. I only used raised radial with my "portable" vertical (though it's up for days at a time) so haven't had that problem.
It doesn't really matter (insulated vs. not). If you use copper, it really doesn't matter. If you used aluminum, I'd recommend "insulated," as the chemicals in the earth can eat that stuff up. Copper seems fairly immune to that.
An inch deep is way more than enough. We keep our lawnmowers set to 3" or 4" and can mow right over radials without even thinking about it.
I live in the country, and my wife was digging out thistles with a spade in my radial field. She managed to cut three (radials), but I was able to splice without much problem. No problem with the mower though. Oh yeah, her blueberry bush gardens share space with my vertical antenna.
73 Rich W9YAC
I just completed the installation of a quarter wave 40 M vertical. My radial field is made up of a mix of copper, both insulated and uninsulated. Some are 14 awg, some 16, and some 22 - whatever I could find in scrap wire that was at least 33 feet long. It has been an interesting experiment, and refreshing to see my data as radials were added agrees nicely with what other have found ( ON4UN & N6LF).
Didn't bury the radials - stapled them. The first set of radials I put down about 3 weeks ago are almost invisible now. I've mowed over them several times with no problem ( I did set my mower deck one notch higher). Yesterday, I found some more wire and am going to call it quits at 73 radials. Probably overkill, but the wire was available and I was interested to see the changes in R,X, and Phase Angle as sets of radials were added.
For DX, this is a fine performing antenna! That's what I was looking for. For "local" stuff, the dipole is much better. Europeans have told me the vertical is 10 to 15 dB stronger than the dipole at 45 feet.
Good luck with your project, and put the shovel back in the garage.
I just used a spade to cut a little slit in the turf, working my way along. Then pushed the wires into the slit with a notched stick. It really doesn't take long.
I've done it both ways - notched the ground with an edger and push the wires in - and stapling to the ground. About 40 altogether, rangin 25 to 65 feet long. Notching and pushing doesn't really take that long and it's not that much work. Where there are tree roots near the surface of course stapling to the surface is the only option.
It's a toss-up whether the little bit of extra work notching and pushing is worth the cost of the staples.
In any case, after several years there's no way to tell which radials were laid by which method. Everything is buried in the roots and thatch now. Except where the radials went over tree roots, they're starting to show where the roots have gotten bigger.