Station Grounding

by N4TB 10/2007

Having a good ground system is always important for any ham station. When running SO2R and having two 1500 watt stations within inches of each other plus a computer interfaced with both radios the grounding system becomes one of the most important parts of the station. Even a small amount of RF on a computer line can render your station unusable for contest operation.

N4TB W4JA Station with two Omni VI+ transceivers and 1500 Watt Amplifiers for each radio.

Over the years I have tried a number of grounding systems with various degrees of success. Having a computer on the operating table brings a new set of challenges in keeping RF out of the computer as well as keeping interference from the computer our of the receiver.

What I have found to work exceedingly well is not new and I take no credit for coming up with the idea.

The station grounding system consists of two parts: the outside system of ground rods and the grounding of equipment on the operating table. Both are equally important.

At the rear of my operating desk I mounted a piece of ½ inch copper water pipe that runs the entire length of the desk. EVERY piece of equipment is grounded to this copper pipe with as short a lead as possible. Everything on my operating table has a ground wire going to the copper pipe. Keyers, SWR meters, Rotor control boxes, low pass filters, etc. This includes the computer and the computer monitor.

It is a bit of an inconvenience to have to remove a ground wire every time you want to move a piece of equipment and make a new ground wire of the proper length but being able to operate without RF floating around the shack makes the extra effort well worth while.

Here in central Florida our soil is mostly sand with very poor conductivity. The outside ground system consists of four 8 foot ground rods spaced four feet apart and connected together with ¼ inch soft copper tubing that is silver soldered to the copper clad ground rods. The ground rods are placed so the center of the four rods is directly below the window at the rear of my operating desk.

1/2 inch copper pipe mounted at rear of operating desk the two inch copper strap can be seen in the center.

The copper clad ground rods are about a foot away from the foundation of the house. They are hidden by the bushes/flowers and covered with cyprus mulch. The yard irrigation system keeps the ground around the ground rods fairly moist. I don't know if this helps but it makes me feel better about the ground system!

The area between our QTH (Avon Park, Florida) and Tampa, Florida is known as the “Lightening Capital of the World” . During our rainy season, approx June through October, the Atlantic and Gulf sea breezes collide over central Florida. The storms are usually small but intense and are accompanied by a tremendous amount of cloud to ground lightening. It is not uncommon for lightening to strike as much as ten miles away from the thunderstorm. The local saying is “if you can hear the thunder, take cover”.

Within a five mile radius of our house there are four tall structures, our two towers, a water tower and a VHF tower on the local volunteer fire station. During afternoon thunder storms I have sat out on our back porch and watched numerous lightening strikes in the citrus groves around our house. So far, knock on wood, our towers have not taken a lightening hit. I believe it is not all luck but due to the grounding system in place on both towers.

My policy during the rainy season is that if I am not sitting at the operating desk all coax and control cables are unplugged and the AC supply to the radios/computer is unplugged from the wall outlet. We have lost several comuter modems due to close by lightening strikes but so far have never had any damage to the radio equipment.

In addition to the station ground I have grounded both of our towers. Three eight foot copper clad ground rods are placed at each tower about 24 inches from each leg. A # 2 copper wire is attached to the tower three (3) feet above ground level and run down to the ground rod. The ground wires run at an angle to the ground rods eliminating sharp angles.

Tower base with ground rods and sloping ground wires

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