Perhaps one of the most over looked aspects of setting up a listening post is a ground system.
Any listener with a table top receiver will need a good ground system to operate their unit at its
optimum level. This piece will deal with setting up a simple yet effective ground system that can
be installed in a short period of time with a minimum number of tools.
The first thing you will need four parts. The first is of course a good ground rod. You will also
need a buss bar if you have more than one unit to ground. Next is a Coaxial Surge Protectors. And finally some ground wire to tie
the whole thing together.
Let us look at the ground rod. Not all ground rods are created equally. When I went to put in my
present system, I talked with several people from our local hydro electric company to see what
they were using. They all agreed on one thing: you need a full sized 10 foot ( 3 metre) rod to be
effective. This length will almost guarantee that the rod will stay in contact with moisture in all
but the driest years. The ground can dry out to quite a depth during long hot dry periods, leaving
shorter four to five foot rods useless. The rods must be kept moist to give a good ground, but
more on this later. I also purchased a rod that had a built in connector so I did not have to
purchase one to keep the ground wire attached. These work best and are easily found.
Next was the selection of the wire I was to use. I ended up selecting 10 gauge copper wire that
was covered in a heavy vinyl jacketing. This area of what kind of wire to use is open to all sorts
of opinions. I picked the 10 gauge as it was readily available and although stiff you could work
with it fairly easily. A coated or insulated wire was chosen to make life easier for me. By using a
coated wire it meant I could run the wire easier as I did not have to worry about it touching
objects that are conductive in nature. Your ground wire must never touch anything conductive
as it will ruin the ground. A clear and unrestricted path from the radio(s) to the ground rod is a
must and coated wire gives you more options of how and where to run the wire.
Remember to strip the wire ends to attach to the ground rod and the buss bar or radio.
The buss bar can be installed if you have more than one radio to ground, or if you plan to add to
your listening post with other equipment that may require grounding. The bar is usually made
from copper because of its conductivity. The bar need not be large. Mine is 3/4 of an inch (2 cm)
wide and 10 inches (25cm) long. I can ground five to six pieces of equipment on it with no
problems at all.
Now that all of the parts have been purchased we can start on a simple but effective ground
system that will last for years. You must first of all choose a site for the rod to be put in. One
very important thing to consider is to keep the run of ground wire as short and as straight as
possible. This will insure a better system. Keep the rod as close to the side of the house that your
listening post is located. If your home is like mine and you may have underground hydro,
telephone, and gas lines as well as water and sewer lines, so please call your local utilities to
have them located before you start putting in a ground rod. You do not want to drive your ground
rod into or near these lines. Putting a ten foot metal rod into a hydro or gas line can ruin your
day!
Once you have selected your spot you will have two options. You can pound the rod into the
ground leaving about 8-10 inches (20 cm) of it above ground, or you can for the deluxe option. I
have gone for this latter route as it will over time help you keep the ground rod damp during dry
times. This involves more work but if you live in climate like mine where the weather varies
over a large spectrum or has long dry spells it is worth the extra effort. Also if you have heavy
clay soils during rains the water will have an easier time to soak into the rock pit instead of
running off. You can mark the ground where you wish to put the bar and measure one foot (30
cm) in all directions from this point. Mark the area off and then dig a hole in the area. This will
result in a two foot (60 cm) square or diameter hole depending on how you dig it out. Either is
acceptable. You should dig a hole that is about 2 feet (60 cm) deep, more if you wish. Once the
hole is completed place the tip of your rod in the centre of the hole. You can now pound the rod
into the ground leaving it the 8 inches (20 cm) above ground level (not the bottom of the hole).
Have a friend help hold the rod as it will move around as you pound it in. Be careful not to hit
your friend as this will hurt the relationship!
Once the rod is in place test it to insure it is in tight. Try pulling and wiggling it to see if it
moves. If it is in tight you have been successful. If it is close to a foundation or is in loose or
sandy soil it will move around. This will not produce a good ground so check it out. If you went
the deluxe route you must now fill the hole with rock. Insure it is hard rock that will stay loose.
Rock such as limestone is of no use as it will break up and form a hard packed area. You need
loose rock fill that will not pack over time. You may also want to put is in a small bag of rock salt
before the rock. This salt once wet will start working on the rod to give better conductivity. This is optional and not needed for all situations. This
rock pit is put into place for one important reason-moisture. During dry periods I water the rock
pit to insure moisture is getting down to the lower levels of the rod. The neighbours do kid me
about it so if you embarrass easily do it at night.
The next step is to install your buss bar is in your listening post. If you are going to use one it is
easy to install. You can make one or buy one readymade. To built one just take your flat piece
of copper and drill two holes is in it. One at either end that will act as anchor points to mount it
on the wall near as possible to you equipment. You can now drill as many holes as you have
pieces of equipment plus one more for the common lead into the bar. This will mean if you have
four pieces of equipment to ground you will need:
Two holes to mount the bar. One at either end
Four holes for the equipment between the two anchor holes.
On one hole for the common lead. Also between the anchor holes.
Each of the holes excepting the anchor holes at the top and bottom will be drilled to put in a bolt
and washer to attach the radios etc to. Use whatever you have at hand. Put in the bolts and
washers into the pre-drilled holes. Using the two mounting holes screw the buss bar to the wall
near to your equipment. Try to keep it centrally located to keep leads to the equipment as short
as possible.
Now that the bar is mounted run short straight pieces of heavy wire from each piece of
equipment to the bass bar. You should use coated wire here to insure no wires touch each other
or anything else. This is very important. Attach the other end of the wire to the lowest bolt and
work your way up to the top. Insure the wire is under the washer so it presses the wire onto the
buss bar insuring a tight and solid contact fit. This is a must. You can now attach a run of wire to
the common at the top of the bar and run it to the ground rod outside. Once again insuring a
solid contact . If your rod had no built in clap you can use metal strapping to get a solid tight fit
to the rod.
When you connect any end of the wire to any piece of equipment or the buss bar or ground rod
insure you strip the wire and then using sanding or emery cloth clean the bare wire to insure
there is a clean contact. You should use washers on binding posts to wire up the equipment. This
will insure a solid contact. Loose contacts are of no use so make sure all contacts are good ones.
If you are using coaxial cable to feed your antenna you should mount a Coaxial Surge Protectors
into your ground system. There are many types you can use but they
all work about the same. Attach the feed end of the coax to one end of the
Coaxial Surge Protectors. Then run another coax line from the other end of the Coaxial Surge Protectors
to your receiver. The Coaxial Surge Protectors will have a ground on it and you can attach
a short ground wire to the Coaxial Surge Protectors and run it to the ground bar. This will
help with static build up as well as nearby lightening strikes.
Your ground system is now completed. Maintenance is little if any. You should from time to
time check the connections to insure they are tight and in the case of the ground rod connection
there is no corrosion. It may need to be cleaned once a year. When it is dry water your rock pit to
insure a good ground year round. I flood mine until I can see the water sitting on top.
Tips from readers:
Tip #1. Heavy duty thick wall copper tubing in 3/4 or
inch in diameter is very strong and with a flattened tip can either be driven into
soil or sunk with water pressure. The soil will work back around the rod in no time if water pressure is used. A thick wall copper ground rod will last a
long time, is not expensive and can be soldered. Want to wet the rod area,
just feed some water in to the top of the pipe. (K1DA)
Tip #2 May I make a comment. I used a post hole digger the hard way, and dug down about 4 feet. I drove my copper ground rod down until I had about 18 inches above ground. Couldn`t go any farther because of rocks and what they call hard pan. I inserted a 1" pvc pipe next to the ground rod, taping it in place. Then I used some creek gravel that will last longer than I will live. About 6", then I filled the hole with Bentonite. This is a substance that resembles driveway chat. BUT, when you add water to it, it gets more fluid. This stuff eventually takes on the consistency of playdough, and it will stay moist in the hottest dog days of summer. If in doubt, just pour some water down the 1" pvc. This has worked very good for me in this dry climate. I believe a lot of states require this element in all electrical grounding because it works so good. Bentonite is used by people that work on farm ponds, or water wells to stop them from leaking. A 50# bag ran me I think, $8.00. This stuff last forever, and I still have 3/4 bag left. You couldn`t possibly get a better ground. I should also mention that I use a good silicone seal on all my connections. 3M makes a very good clear calk, spreads nicely, and really seals out the moisture. No moisture, no corrosion. I have taken down antennas that have been up 5 years before a storm got them, and the connections were just as new and shiny as the day I put them up. Everything else was weathered, but not my connections. Just thought I would pass it on for trouble free connections. 73`s, Bob KC0VEA.
That is it you now have a good ground system that will last years.
E-MAIL AMANDX
