There are several ways to install your ground radials. Best wire to use is copper, of course because of its conductivity and resistance to corrosion. Typical 14 gage or 12 gauge house wire with the insulation left on his perfectly satisfactory. Any wire gauge 20 and above will be satisfactory. Some say enamel covered “magnet wire” also is excellent for burial. Copper clad steel wire is probably the next best. Aluminum definitely should not be used because it will deteriorate quickly in typical soil. Also, stranded wire with its increased surface area will quickly deteriorate; do not use stranded wire.
Radials can be rather small diameter wire since so many of them exist to share the return currents and they are in parallel with the ground currents in the earth as well. Each radial is going to carry very little RF current. Ground radials need not be resonant. This is a misconception based on elevated or ground plane type elements. True ground laid radials designed to supplement ground return currents in the earth need not be resonant. Varying lengths up to 1/4 wavelength (or your property line!) are very adequate.
Following we will show with several methods for laying down radial wires: one involves digging a trench, another one is just laying the radio wire on the lawn, while others suggest a elevated radial system. These will be discussed following:
Using an electric edger/trimmer to cut small trenches
An edger will do the hard part of cutting a slot in the turf for a radial wire: How to bury radials NØRQ.
Laying radials in the grass
We will assume that you have a normal city lot with a lawn for your backyard. Here we will lay down radials in the grass and the grass will quickly grow over the radial wires.
An Easy Way to Install Ground Radials
by Brian, W9HLQ
In the past, I never seriously considered installing an extensive array of ground wires for my HF system due to the daunting task of making trenches to bury the wires. Having an array of ground radial wires has been a known need for this station, but the labor kept me from doing anything. I tried to address the problem by driving lots of ground rods around the tower base. This certainly is inadequate!
I have a typical city lot 70 feet wide and 110 feet deep with the house plopped in the middle. Getting a large number of long runs of wire for a radial “farm”, will be a compromise at best. (See diagram at the bottom of this page). However, any wire that you can get down will immensely increase the efficiency of your 160 meter antenna system. Plan in running the wires where you can; making turns if you must to avoid trees, shrubs, and swing sets.
As mentioned in other articles, you will want to tie this radial system into your other grounds, such as the ground rods, water pipes (assuming they are copper or galvanized pipe), and the house electrical ground. This is referred to as the single point ground.
I use an electrical ground block used in electrical service boxes. See picture below. Mine was too big and I sawed about 6 inches off to give me about 24 screw attachment points for the radials. This block is attached to the tower with stainless steel straps. This becomes the central ground point mentioned above. Click here to see DX Engineering’s radial mounting plate. Once things were wired in place I used water resistant spray Lithium Grease to seal out the weather. The grease looks messy and it is; but it is very easy to use and seems to do the job.
|Long grounding block is cut down to size and strapped to the tower to serve as a common grounding point.||
Block bolted to tower leg provides attachment points for the ground radials. Wide strap ties tower base to inside bulkhead grounding plate
If your lawn’s grass is rather long, it might be worth while to mow the lawn fairly short. This will allow the wire radials to lie nearer the ground initially. Notice that within a few weeks that the grass will grow up over the wire and the wire will disappear! It is amazing and so simple to do. Suggestion: place the wires down in the late fall after your last mow. Then you have all winter for the wires to settle into the grass…and when the spring rapid grass growing occurs, the wires will be ready to be grown over. Works like a charm! Otherwise, get those wires down before the spring growth spurt.
Lay out your wire in the directions you wish to run the radials. It will help to remove the natural tendency for the wire to curl and kink up by attaching one end to a fence post or tree. Then pull the length of wire very hard to stretch and straighten the wire. This works best with #12, #14 or #16 gauge copper house wire. (You can use wire as thin as #20; see footnote). You can leave the insulation on. Start at the ground point and work out to the end of the radial wire. Consider using garden tools to bury the wires around your tower if appropriate. Continue by using the staples described below along the radial wire. Ground rods along the radials do no good for RF, however they will help with lightning protection.
Make the staples for the wire out of old coat hangers, #10 or #12 copper house wire, or I use #18 gauge galvanized steel wire. This steel wire is available in 110 foot spools from Ace Hardware in a handy dispenser pack. I cut 6 inches of wire and then bend it into a “U” which is used as a “staple”. The two legs of the staple grab the earth well enough that the wire does not pull out. Place the staples about every 2 feet or more often if the wire fails to lay flat. Having damp soil will make the staple insertion much easier. Of course, you will need a lot of staples. I find making them while watching a long foot ball game is a good use of your time during the endless commercials.
Insert staples to hold wire down. Can carefully mow over wires after about a week’s growth.
Use your free time and bend a supply of staples
Regarding the routing of the wires, they should radiate out from the common ground point in a fairly straight line. Don’t meander around too much; as this will add little to the effectiveness. Run some longer wires around the house each way, if possible to obtain a longer length. For 160 meters some runs of 160 feet is desirable. According to the QST article (ref. footnote below), plan on about 50 radials, ideally. Since my ranch house rambles over much of my lot, I was able to only get about 10 unique runs from the base of my tower. Still, I am able to put out a respectable signal on 160 from my 50 foot tower system. All of the wires I put down have long disappeared into the soil.
The connections are over sprayed with white lithium waterproof grease.
This has kept my connections corrosion free (and messy looking) for years.
The copper grounding block is separated from the aluminum tower by a stainless steel plate for corrision control. Stainless steel hose clamps binds the “sandwich” together.
Now you are well grounded…..congratulations.
Radial System at QTH of W9HLQ
See how well this ground system works. See Case Study based on this arrangement.
Here is another way to install ground wires. Drag the sled and the wire is buried cleanly leaving the sod intact.
Sled not available at Walmart – you must make it youself. If you are serious about ground radials this is the way to go!
Grounding System at W9HLQ
Two copper straps tie the tower to the inside bulkhead plate. Copper block from power distribution panel is used to terminate my radial farm. Stainless steel is used to separate the copper terminal block from the aluminum tower; this prevents dissimilar metal electrolysis corrosion. Stainless steel straps provide bonding forces. Everything is sprayed with water resistant lithium grease to reduce corrosion. It looks messy, but it works well.
Cables on the left go to the
radio gear, the cables on the right side of the bulkhead go up and outside to the tower common ground point (see tower base photo above). It looks messy, but hopefully the lightning will not care.
Cables are removed from bulkhead
when storms threaten. The bulkhead is grounded by heavy copper straps to outside tower common ground point, local water lines, and the electric power ground. Lightning surges may well travel down the feedlines and into the house. The bulkhead hopefully will then direct those surges to ground. Simple feed through coax fittings are used. A better system
would include the use of gas discharge protectors.