Ground Radial Cutting Tool
Mike J Roda (N0KFC)
on
December 9, 2003
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I came across a tool for getting ground radials buried into the sod. I needed to get some radials placed into my back yard and the frost was beginning to already set into the ground. I had tried several different methods to do this in the past and nothing was working very well.
Then I came across this yard tool used for manually edging along sidewalks. It is called a Steppin’ Edger and a company called Hound Dog, web site
hound-dog.com, manufactures it.
They have some pictures of this tool on their web site. It basically will cut a groove about 1/4 inch wide and 4 inches deep & about 10 inches long in one cut. After the radials have been placed into the grooves the 1/4 inch line will just disappear in a couple of days. A person can place many radials with this in a very short amount of time with very little effort.
Mike Roda
N0KFC
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Ground Radial Cutting Tool
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by RFSOAKED on December 9, 2003
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Thanks for the heads up on that tool. That looks like just the ticket for installing some radials when the cold hard ground here in the Midwest thaws this spring. I have been thinking about going with a new vertical and planting as many radials as necessary for good performance according the manufacturers specs, and maybe even going with a few more for good measure.
The last time i installed a vertical and ground radials i must have spent a week just digging them all in, a couple a night after work until they were all done. That tool looks like it would make a lot quicker job of it, not to mention that it doesnt do much damage to lawn so it will heal up nice and fast.
Its about time something useful gets posted on this site, i was starting to give up on finding any use for it!
73
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Ground Radial Cutting Tool
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by W8OB on December 9, 2003
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I purchased something like this about 15 years ago from the "Frank's Nursery" store for $9. Its worked great to edge around the sidewalk as well as bury the mother lode of radial wires in my back yard. Over the years I have buried believe it or not 10,000 feet of wire back there with several tie points rising out of the ground in out of the way places. After a few days the dig marks are gone and all you have is outstanding vertical performance.
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Ground Radial Cutting Tool
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by KR1ST on December 9, 2003
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Thanks for the great tip on this tool, Mike! It sells a heck of a lot easier to the wife that I'm buying a gardening tool rather than some ham tool to raise the copper level in my yard. :) Of course, it may have its drawbacks, too...
I just checked Home Depot online and they sell 'em for $24.69. Just do a search on their website for "hound dog".
I love these short quick tip articles.
73,
--Alex KR1ST
http://www.kr1st.com
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RE: Ground Radial Cutting Tool
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by K5DVW on December 9, 2003
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Interesting idea and use for that tool. I guess I am lazy tho, I just laid my radials out on the ground and used U shaped pieces of coathanger wire to pin them down every meter or so. The grass grew right over them in about a week or two. Did the same with my coax.
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Ground Radial Cutting Tool
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by W5WJP on December 9, 2003
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Using a chicken wire mat of about 12'x12' for radials works quite well too. In a couple of weeks the grass grows up through it and the lawn mower goes right over the top. No digging unless, of course, you are a no coder or are using a fan dipole. hihihi.
73
W5WJP
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Ground Radial Cutting Tool
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by K8DXX on December 9, 2003
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Also, thanks for the heads up on this new alternative.
I have tried many ways of burying radials and like the last comment, find that stretching out my radials on the sod and tieing them down with wire coathanger "staples" is both easy and effective. The grass covers radials installed this way so fast that if you ever wanted to remove them (as in 4 weeks later) they would already be an integral part of the lawn. Question... I don't know how these wire staples would penetrate frosty/frozen ground?
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RE: Ground Radial Cutting Tool
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by KC7MM on December 9, 2003
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This is a wonderful idea and I am going to zip down to the local Home Depot and pick one of these up. I need the excercise!
There is an easier method, however, if you physically can't, or don't want to do all the manual labor involved with this tool. Fifteen years ago, I borrowed my Elmer's (NR7B's) elctric lawn edger. I first laid the 40+ radials on the ground where I wanted them buried, then ran the edger next to them. It created a 3"deep 1/4" wide trench. I used a thin wooden dowel to push the radials into the ground. It took me all day, but I was able to bury 3,700' of radials in one day that way.
Dale KC7MM
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by K0BG on December 9, 2003
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The last time I needed to bury radial I tried to use a similar tool. After about 30 minutes my hands and legs got tired. I had an old B&D hand power saw with a bad bearing which caused the blade to wobble a bit. Unsuitable for wood, but by replacing the blade with an abrasive cutting blade, I laid 50 radials in less than 3 hours. Nowadays, I use a commercial power edger and I'm sure it would easily cut the requisite grooves. You can rent these at any rental center.
Alan, KØBG
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by N3ZKP on December 9, 2003
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<< No digging unless, of course, you are a no coder or are using a fan dipole.>>
I understand a fan dipole makes and excellent radial system if buried six feet under. <g>
Lon
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Ground Radial Cutting Tool
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by WB2JKM on December 9, 2003
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I tried using a similar tool and about wore out my feet, back, and hands before I decided there had to be a better way.
A powered lawn edger makes the job a whole lot easier if you really want to put the radials under the sod in a hurry. A gas powered edger, common in the South, will make a 6" deep (or shallower if you prefer) slit trench about as fast as you can walk behind it. You push the radial wire into the slit trench and then stomp the narrow trench shut. I found that 14 or 12 gauge wire went in easier due to the added stiffness of the wire.
I put down about 1000' of radials in under 4 hours using this method. Coax goes in really fast too. The lawn damage was pretty minimal and healed up within a couple of weeks. You can rent one of these powered edgers for under $20 a day in most places.
One point of caution -- the telephone and CATV drops are usually not buried very deep so be careful you don't cut both of these in the process ... no matter what tool you use.
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RE: Ground Radial Cutting Tool
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by W0FM on December 9, 2003
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The local cable guy turned me onto this device some time ago. I agree that I soon looked for a quicker (read: less physical) approach.
So I cut a 12" circle of 1/8" aluminum and sharpened the outer edge with a grinder. I ran a bolt through the center of the aluminum disk and through a retired mop handle. This created sort of a giant pizza cutter. It worked quite well on damp or soft soil. Radials went down in no time at all.
After reading about those who used pieces of coat hangers to tack the radials to the ground, leaving them to be grown over by the turf, I began using my industrial grade staple gun with the largest cable staples it would hold. I laid the radials out on the ground after mowing the grass very short. Then I simply stapled the radial to the ground every 2-3 feet. This was quick and much easier than making staples out of coat hanger wire. And, the staples only had to hold for a couple of weeks before the turf took over. I later scanned the area with a 15lb magnet to retrieve any loose staples before they found my bare foot.
But I still think that someone should manufacture and market my "giant pizza cutter" for radial wire installation.
73,
Terry, WØFM
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by W4VR on December 9, 2003
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It's nice to see someone posting an article of some utility for a change. I have been using a square blade shovel for years, but I think your gadget would be easier on the foot. Another technique I've also used in grassy areas is to lay down the wire and clamp it to ground with cut-up pieces of coat hanger (U-shape)...in time the grass will grow over the radials and the coat hanger pieces will rust away.
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by KD2E on December 9, 2003
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I think this method is making more work than the job requires. The staple method some folks mentioned works great....Until I found myself fresh out of wire coathangers!!!
At the local fleamarket, I found the same exact thing...only manufactured! Bags of metal V shaped staples. Used for routing low voltage lighting wires, or some other gardening task. A bit stronger and longer than my coat hanger staples. I also use them for arranging 'seeper' hose around flower beds.
For your vertical, just hook a wire to the antenna, walk it out to the end, hold it on the grass, bang a staple on it with a rubber mallet, then walk toward the antenna 15 feet or so and bang another in.
In two weeks, the whole thing is covered.
Couldn't be easier!!
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RE: Ground Radial Cutting Tool
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by KC8VWM on December 9, 2003
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Here's an idea. Find an old coffee can with a 6" diameter lid and remove it using a standard issue military grade can opener.
Secondly, drill a hole in the center of the stiff round metal disc using a small drill bit. What no drill!? Try driving a nail through it then! Any other excuses? let's move along...
Attach it to your weed whacker and hold it horizontal and evenly to the ground as it spins.
Remember to walk backwards while the weed whacker is spinning and always ignore that water pail and other similar objects you left laying around in your backyard since the last NFL season. These are the usual things that your wife keeps nagging you about leaving in the backyard for the past 6 months.
It is always more effective that if, and when you do trip or fall over such objects, that the cutting blade is still spinning at rate of 7200 RPM. Remember, the cleaner the cut to your arm, the easier it will be to reattach during surgery. However keep in mind that you are drawing a line in the ground today, you are not performing experimental surgery today. Try to remained focused on the task at hand. You will become an accomplished ARES/RACES surgeon another day, for now we will just put radials in the ground.
This action will usually be met with the usual stares and finger pointing coming from your neighbors as it kicks up sod. They will be thinking the usual barrage of thoughts like, "What is that crackpot doing now?" or "I just know that guy screwed around with my wife" or "When is that idiot going to wash his car?" etc.(you know, the same stares received when you put up your antennas)
It would be a good idea to leave Fido in the house unless you are looking forward to saving you wife valuable time by offering to prepare exquisitely delicious Fido culinary cutlets on the BBQ for dinner that night.
Don't worry about ruining the cutting wheel. These high tech metal wafers (as seen on T.V.)can be combined together to provide for additional ground cutting power. This technological scientific marvel as developed by advanced NASA technical engineers is easily replaced and can be thrown away after use, or even during use for that matter. They are really quite versatile in this respect.
Do this at your own risk. The author assumes no responsibility or liability associated with this suggestion.
Lastly, if you can't chew gum, send CW and tie your shoelaces all at the same time, make no attempt at this.
:)
Charles - KC8VWM
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Ground Radial Cutting Tool
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by N0TONE on December 10, 2003
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Only one problem with this - ABOVE GROUND radials work better. I've done the experiments with AM BCB transmit antennas. The benefits of the radials diminishes very sharply when they hit the ground, then it gets worse the deeper they go.
I STRONGLY recommend, for ham installations, to string the radials 10 feet off the ground. At that height, people can walk comfortably underneath them. At 10 feet off the ground, my experiments and modelling show that four radials (nominally 1/8 to 3/8 wavelength long) for 20 meters outperforms 120 of them buried 1" deep. The closer to the ground, the more of them you need. The higher the frequency, the closer to the ground they can be. But, figure four of them is as good as you can measure, if you can have them 1/20th wavelength off the ground.
If, however, you absolutely can NOT elevate them (community rules, desire to avoid visual clutter), then IF AT ALL POSSIBLE, lay them on the ground without burying them. I have been in that situation, and have successfully used the idea of stapling them to the earth (after a very short grass cut and thorough raking) and then just letting the grass grow up around them. Do NOT bury them!!!
A comprehensive explanation of why this works out this way is found in the book "Low Band DX Handbook" by ON4UN.
AM
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RE: Ground Radial Cutting Tool
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by K9KJM on December 10, 2003
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I have buried as many (Or more) copper radial wires
than most over the past 35 years...... Many good ideas presented here. My observations agree with most:
If you are going to bury, Do it while the sod is as
WET as possible. After a heavy rain period, Soak with a garden soaker hose, whatever. I have mostly just used a plain shovel to "lay the sod back" from left to
right, putting the copper wire in the shallow trench, then "flipping" the sod (Which is still "hinged" to
itself) Back over the wire. Most any old used, cheap
copper wire will work. But I try to use as heavy a gauge as possible near the tower/antenna, As it is also
adding to the lightning ground system. And add ground rods (space twice the distance apart as the depth) for the first 75 or so feet from the tower. True "hard" silver solder (Silfoss) as used by the refrigeration trade) is the cheapest high quality way to bond connections. (MAPP gas in a small hand held torch provides enough heat to flow)
I agree that the "elevated" tuned radials are much more effective than buried. BUT everyone reaches a point where there are more than enough wires overhead..... (And the elevated wires do not help safety or lightning grounds) Forget trying to "tune"
radials when getting on the ground or buried. Just install as many, and as long as possible. (soil moisture and chemical changes will "detune" all of your efforts to "tune" radials anywhere near the ground. Try to get them longer than a quarter wavelength if possible. They do not need to run in a straight line.
The depth really does not make all that much difference, But as mentioned, The closer to the surface, the better...... I think that the "staple"
method is really about the easiest, best way to do it.
For good information on lightning protection, See the tech notes on the Polyphaser site:
http://www.polyphaser.com/ppc_pen_home.asp
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RE: Ground Radial Cutting Tool
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by K9KJM on December 10, 2003
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I failed to mention in my last post that to help with lightning/safety protection grounding, Radials need to be BARE copper. Never use insulated wire thinking that you can "tune" them...... Changing soil moisture and chemical composition will "detune" them in short order!
An ideal installation would be similar to commercial
AM broadcast stations: Flat copper strap run out from the tower and silver soldered to copper strap that surrounds the tower a number of feet out, To which the ground radial wires are silver soldered.
(Flat copper strap material can sometimes be gotten from "upscale" roofing companies at a reasonable cost.)
The narrow 2-4" wide that is ideal for grounding is
too narrow for most roofing applications)
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Ground Radial Cutting Tool
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by W4VR on December 10, 2003
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Some people have good luck with elevated radials. Soil conductivity appears to play a major role in the efficiency of these systems..especially in areas where the soil is mostly clay (Northern Virginia). I tried 8 elevated radials with a 160 meter top-loaded vertical (T-antenna) and the antenna worked much better when I lowered the radials to ground level...go figure.
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RE: Ground Radial Cutting Tool
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by N0TONE on December 10, 2003
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No, you do not have to tune elevated radials.
Try doing the modelling (you need NEC4, not available for Windows, so you'll have to run under Linux) or just build model verticals for two meters and try sitting them over your back yard at scaled elevations.
With only four elevated radials (visually only a little more cluttered than a single dipole), the efficiency is better than a LOT of on-ground radials.
As long as the elevated radials are at least 1/8 wavelength long, they will establish the antenna efficiency. Longer is better, but not dramatically. If you "tune" them, you will adjust the antennas VSWR - that's all. I think we've all grown out of the mistaken belief the VSWR indicates the "goodness" of an antenna, so we all know that time spent optimizing VSWR doen't yield much return on DX.
I did the NEC modelling, then did experimentation with a 100MHz scaled model (FM broadcast), then did the real thing with AM broadcast, over good and poor soil.
It works - elevate them. Above the ground, you need a LOT fewer of them, and it's not visual clutter for that reason.
You are right, elevated radials don't help a lot for lightning protection. But if lightning protection is the goal, then you don't do "radials" per se. You do a perimeter wire first, then start filling in the mesh. A very different structure, geometrically, than "radials".
Making one set of on-ground or under-ground wires serve as both RF counterpoise and lightning drain compromises both functions in serious ways, and should not be done unless you have no choice. By combining them, you've made a lightning drain with an increased risk of single-point-of-failure, AND you have coupled the lightning's energy very directly into your station. And, as I said before, the on-ground radials are a LOT less effective than above ground.
Per modelling and measurements, just as an example, 30 on-ground radials are about 15dB less effective than four elevated radials. Put those 30 on-ground radials two inches underneath and you lose another 3-10dB, depending on soil. Once you're two inches deep, you can keep on going - the first two inches are the killer anyway.
I've heard a lot of guys claim that "verticals radiate equally poorly in all directions". Some of those guys have monstrous radial fields. Here was the tell-tale story:
One fellow was exasperated at how poorly his vertical worked. He had 120 radials buried about 4-6 inches. He pretty much stuck with using his dipole at 35 feet.
One storm season, he got spooked about lightning protection. He drove four ground rods in the yard, separated by a lot of distance, then ran #8 wire on top of the soil to connect them, and also ran a wire to the contact point for all the radials. His vertical suddenly came to life. The four on-the-surface #8 wires were acting like radials-and were far more effective than his 120 buried radials. He at first blamed it on the ground rods. As an experiment, I had him disconnect the wires from the ground rods, but leave the wires connected to the "radial" tie point - no reduction in effectiveness (we measured field strength two miles away. For the final experiment, I had him drive simple little 1X2 furring strips into the ground to elevate the #8 wires for the ground rods. They rose from where they contacted his "radials" (right next to the base of the vertical) to the 8 foot height level, about 4 feet from the antenna (about a 45 degree upslope) then stayed about 8 feet, on a series of furring strips, out to the end of the #8 copper. The length was a bit less than 1/8 wavelength. He got another 10dB of signal strength.
So, he re-connected his bare copper to the ground rods for the lightning protection, then added four elevated gull-winged radials. He took the dipoles down within months.
AM
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RE: Ground Radial Cutting Tool
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by NI0C on December 10, 2003
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Since I have over half a mile of radials in my back yard, I thought should weigh in with a comment on this most interesting thread. This is one area where laziness pays off-- most of my radials are laying on top of the ground, on top of the swimming pool (covered for the winter), encroaching on vegetable and flower garden areas (unused during the winter) and even on the driveway. Of course, the down side of this is that I have to take up most of my radials in the Spring. However, my radials are primarily for low-band DX'ing-- which is mostly a winter sport anyway.
Some day I might use one or more of the tips provided by this discussion to bury a few more of my radials-- to get them out of the way and to have a more effective antenna during the Summer months. By the way, I always use insulated wire to retard corrosion of the wire and to blend in with the environment. I've been purchasing No. 14 gage insulated wire in 500 foot spools at Home Depot at a very reasonable price.
73 de Chuck NI0C
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by N3ZKP on December 10, 2003
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My vertical (HF-6V) has no radials, per se.
It is bolted to the frame of a 30-ton a/c unit almost in the middle of a 23k sq ft corrugated steel roof on top of a two-story building in downtown Baltimore. :)
Lon
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RE: Ground Radial Cutting Tool
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by NI0C on December 10, 2003
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NOTONE:
Thanks for reporting the results of the experiment with (slightly) elevated untuned radials! I can elevate at least a couple of mine to six feet at the ends by tying them to the top of my wood fence. I'll try it soon! Thanks again.
73 de Chuck NI0C
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by KA4KOE on December 10, 2003
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VWM:
Your humor is disturbingly similar to mine!!!!
I LIKE IT!!!
OH, be sure the metal disk has a nice coating of iron oxide on it prior to energization of the trimmer motor.
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by NI0C on December 10, 2003
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N3ZKP:
I'll bet your antenna plays well with all that metal for a ground. About 15 years ago, I had good results on a much smaller scale operating from an apartment. I used a magmount to secure a "hamstick" mobile HF antenna to an outdoor utility box that I assumed contained a transformer. The box was approximately a cube, about two and a half feet per side, and it formed my ground system! It played amazingly well on all bands from 40m to 10m with just 100 watts. I used no other radials or counterpoise wires at all.
73 de Chuck NI0C
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by N0TONE on December 10, 2003
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ZKP, I bet that antenna played well.
Years ago (in the 60s), one of the schools where I taught had a ham club. The club didn't have enough money to buy a tower, yagi and rotor, so we "compromised" and bought a multi-band vertical - 14AVQ comes to mind. We mounted it on top of the building. It seemed too simple. The building had a metal roof, and was about 600 feet by 600 feet...we were mounted about 1/4 of the way in from one edge...it was a single story building.
Boy, did that antenna play. The kids had DXCC under the club callsign in less than a year, without entering ANY contests.
I did not understand grounding and radials then like I do today. I was then a math instructor, electronics was a hobby. If I had such a building available today, I would immediately plant a vertical and not even think about a tower!
AM
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RE: Ground Radial Cutting Tool
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by KC8VWM on December 10, 2003
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<<<<Your humor is disturbingly similar to mine!!!!
I LIKE IT!!! <<<<
Philip,
We are just a couple of sick SOB's that have been exposed to way too much RF over the years. I like your profile information here and enjoyed your webpage. Especially the photo of you operating ATV equipment at such an early age...
All the best to you, Shari (KG4KTW) and the little cracker snachers Sarah and Jordon during the holiday season.
Warmest Regards,
Charles - KC8VWM
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by W4EF on December 11, 2003
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NOTONE wrote <<Per modelling and measurements, just as an example, 30 on-ground radials are about 15dB less effective than four elevated radials. Put those 30 on-ground radials two inches underneath and you lose another 3-10dB, depending on soil. Once you're two inches deep, you can keep on going - the first two inches are the killer anyway.>>
I had the opposite experience with my 160 meter marconi when I was in Florida. Initially I had a counterpoise of 4 elevated radials up around 8 to 10 feet with no ground radials. Performance was medicore at best. I then layed about 3000' of radials on the ground (80 to 100' each). Although I didn't do any rigorous field strength measurements, it was clear (at least to me) from on-the-air experience that performance improved greatly when I added the large on-ground radial field. YMMV.
73 de Mike, W4EF.................................
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RE: Ground Radial Cutting Tool
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by N0TONE on December 11, 2003
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Mike, not surprised about your luck on 160. At that low frequency, you need more elevation, or more radials. My own 160 meter vertical required the elevated radials to be about 25 feet high. One advantage of that is that they become less visible.
The way the broadcast towers do the elevated radials is to plant the tower right on the ground, in concrete. Then, at some height above ground, they insulate every tower leg, and then the active portion of the tower is the portion above that. The elevated radials are mechanically attached to the tower at that point. Some installations DC connect the radials to the bottom section, and some don't, but ALL installations DC connect the upper and lower halves of the tower (by way of a large inductor) for lightning protection.
An 830kHz BC installation I did a few years ago has the elevated radials at 90 feet!
On my 160 meter vertical, I don't "gull wing" the radials as I have often described. Instead, I created a "cage" of wire that rises up around the tubing that is the vertical. I selected the cage diameter to create, in effect, a 25 ohm Zo transmission line out of it. This "cage" rises up to the 25 foot mark, where there's a non-conducting structure mechanically affixing it to the pole. At that level, I have my radials attached. Mine head outward from there and are about 100 feet long. I tried sloped and straight, and straight gave stronger FS measurements. You DO have to get them high enough for the frequency in use. When I sloped them downward, they were getting too close to the ground.
As I said before, 1/20th wavelength off the ground really is the minimum - and for 160 metees, 1/20th wavelength calculates to be 27 feet. I would expect radials elevated only 10 feet on 160 to be very disappointing. You can overcome the problem by using more of them. Somewhat speculatively, if you could only elevate them 1/50th wavelength, as you did, probably you'd want to use at least 16 of them. I think the number required, for a given performance, tends to rise inversely as the cube of height above ground. That's not a mathematically derived relationship, just about what the curve looks like when models are compared with each other.
If you do as I did, and run the radials upward very steeply (in my case, straight up), the effective height of the antenna is reduced by the elevation of the radials. So, my 90 feet of aluminum tubing is effectively only 65 feet high - it's a 1/8 wave vertical. I use a top hat (more alumunum tubing) to get it resonant, then the base impedance is about 13 ohms, which is partly tuned by the 25 ohm synthetic t-line, and more components in a housing at the base.
In my case, though, there's my house and neighbor's houses, and I would not have been able to plant enough radials to be effective. With the radials at 25 feet high, the neighbors accept them running into their trees, and one of them travels across the street. I am deeply indebted to the one neighbor who allows me to use a tree in her yard as an attachment point for some of my guy ropes!
For 40 meters and higher, 10 feet elevation is great. It's a "magic" height not because it's a minimum for RF effectiveness, but because it's a minimum for people walking underneath. On 80 meters, 15 feet up would probably be a better choice, and on 160, twice that ought be the minimum.
Most dimensions in antennas are inversely proportional to frequency, and the required elevation of the radials is no exception.
My elevated radials are made of 18 gauge magnet wire, and are quite literally invisible at 25 feet high. No visual clutter at all.
If you've got a 160 meter vertical, your visual clutter comes from all the guy ropes holding it up, anyway!
AM
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RE: Ground Radial Cutting Tool
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by K2WH on December 11, 2003
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Well, #1, buried radials are not as efficient as radials on the ground or elevated for that matter. If you happen to be single, have no kids and no neighbors that walk across your property, DON'T BURY THOSE RADIALS.
I just stake them every so often with those green plastic garden stakes. I walk along with a rubber mallet and a load of the green plastic stakes and just one blow and the radial and stake are flush with the ground. Holds them real tight too. After a while, they are overgrown with the grass or weeds, depending on your gardening skills.
No staples, no machines, unique inventions or, excuses. Just lay them on the ground and use the plastic garden stakes. Put those radials down and enjoy fantastic DX with that vertical.
K2WH
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RE: Ground Radial Cutting Tool
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by WB2TPS on December 12, 2003
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I use "SOD STAPLES" available at Home Depot. They are "U" shaped and about 7 inches long. A box of 100 or so is about $7.
They are good for radials, coax, low voltage lighting.
I whack 'em in with a hammer and in a few weeks you can't find the wires. Check the WEB for "biodigradable" sod staples if rusty metal in the lawn is a concern.
This was a lot less work than using a motorized lawn edger and the lawn heals faster.
Jim
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RE: Ground Radial Cutting Tool
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by W4EF on December 12, 2003
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NOTONE Wrote:<<
If you do as I did, and run the radials upward very steeply (in my case, straight up), the effective height of the antenna is reduced by the elevation of the radials. So, my 90 feet of aluminum tubing is effectively only 65 feet high - it's a 1/8 wave vertical. I use a top hat (more alumunum tubing) to get it resonant, then the base impedance is about 13 ohms, which is partly tuned by the 25 ohm synthetic t-line, and more components in a housing at the base.>>
Interesting. In my case I was using a Palm Tree for the vertical support. The antenna was a 40/80 meter parallel dipole. On 160 I shorted the center conductor and shield of the coax together and fed it as a "Marconi". I probably could have got the elevated radials higher, but my overall height was limited and I am not sure how the increased radial height would have traded off against the comensurate shortening of the vertical radiating section. That would be interesting to study.
73 de Mike, W4EF.......
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Ground Radial Cutting Tool
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by KE4ZHN on December 12, 2003
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This is a good idea. If you already own a power edger, you could probably use one of these to accomplish the same thing alot easier and faster though. They are not that expensive, and the little 3 horse Briggs can cut grooves in the dirt much faster then you can by hand. There are also electric models available, although they are not quite as powerful so they may bog down in thick lawns. Still this sure beats digging the radial wire trenches by hand thats for darn sure!
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RE: Ground Radial Cutting Tool
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by N3ZKP on December 15, 2003
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Chuck and AM:
It plays VERY well!
When I was putting it up, I talked to Bencher and described the mounting situation, only mentioning that I wanted to bolt it to the A/C unit. The fellow I talked to said that should work but suggested that, If possible I lay a few radials on the roof just for good measure.
I asked him if they would interract adversly with the metal roof if I just laid them across the rubber membrane covering the roof. He asked how big the roof was and was the A/C unit connected to it? I told him it was 23K sq ft and the A/C unit was welded to the underlying steel roof beams and bonded to the roof itself.
For several seconds there was dead silence on the other end. He finally said, "if it doesn't work beyond your wildest dreams, call me back." and he hung up.
I've never had reason to call him back. :)
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Ground Radial Cutting Tool....?
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by N8YV on December 18, 2003
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I just don't understand it all! I use a cheap, old pair of 6" diagonal cutters to cut MY ground radials!
That device you posted a picture of is WAY too big for ordinary #14 wire....why all this fuss?
HI
Happy Holidays (or whatever else you celebrate)!
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RE: Ground Radial Cutting Tool
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by AA5CK on December 19, 2003
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Hey NOTONE
You are right on! But I am not supprised that more hams haven't realized this.
You can also get by with as few as couple of radials if they are elaveted.
You bet, check out ON4UN's book, "in some cases a vertical with one radial will perform as well as one with 120".
And also check out Ralpf Holland, VK1BRH's site and links, "in some cases a vertical with one radial will OUT PERFORM one with 120".
But then maybe it wouldn't be called a vertical??
Still a lot of room for experimenting!!
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Ground Radial Cutting Tool
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by AC7CW on October 10, 2004
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A couple words of caution regarding radials. Using chicken wire can be disastrous because corrosion can occur at the unsoldered junctions. The corrosion will form diodes which will rectify your RF and produce re-radiated harmonics which can cause interference.
The other thing is pets: Dogs will take off after something and run right into wires that they know are there. One of my dogs ruined one of his eyes by running into an elevated radial, pretty sad day for us, I can tell you that. You should put some flags or something there so the dogs can get a visual on the wire no matter how excited they are.
Elevated radials work great, I had a multi band vertical from Cush Craft and I followed the instructions that came with it. I put it up on a push-up about 10 feet and ran the radials sloping downward, all elevated. I worked the world with no problem. I never got signal reports like a beam would have probably, but I got out for sure.
Max
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