By Frank Ross
“Properly grounded” is a term that gets tossed around a lot in electronics conversations, but assumptions on the part of both parties in these discussions can contribute to costly mistakes. For most, the need for a detailed explanation eventually becomes obvious. Ham radio enthusiasts often raise the question of grounding, perhaps prompted by the knowledge that they are often holding onto a microphone cord that is ultimately connected to an electrically charged system and a very tall metal antenna.
The questions most often asked are:
Just what does it mean to be properly grounded?
What makes one ground proper and another improper?
And the most critical question is; what components need to be grounded properly?
For many ham radio enthusiasts, a complete understanding of the proper grounding procedures of a radio station was the last thing on their mind when they un-boxed their new receiver/transmitter and started to set up a ham station. Although it doesn’t have to be a complicated process, there are two critical steps to grounding a ham radio station that will insure your personal safety, the safety of your equipment as well as your home and improved performance of your radio. Maintaining your personal safety and that of your equipment should be a high priority when dealing in ham radio installations. The other aspect of grounding relates to performance, since grounding can affect signal efficiency as well as the clarity of messages that you send and receive.
Types of Radio Grounding
There are two aspects of safety and grounding to consider; RF Grounding and Surge Protection. Although there is no total protection against a direct lightning strike, a grounded system is always best.
Radio Frequency (RF) Grounding is a completely different concept in grounding, compared to surge grounding. A radio frequency is an Alternating Current (AC) signal and it has impedance. An RF ground wire is nothing more than a short antenna. An effective RF ground needs to be no less than a quarter wave-length at the highest frequency used. Ham Radio connections should be made with as few strands as possible and preferably a bare solid wire. This is very important, RF performs best on smooth surfaces, therefore, it is not recommended to use braided cable for RF connections.
Storm's Ham Radio grounding kit w/call letter engraving.
All radios, tuners, meters, etc in a radio system should be grounded in a star ground configuration. The common point should be located at the tuner, if one is used, otherwise use a copper ground bus bar and make all connections on the bar. All Connections to radios should be with either insulated or bare wire with as few strands as possible. Now you need to connect your internal ground run directly to the ground outside where you should have a ground rod driven into the soil for the connection point. This rod will in turn be connected to all your other ground rods if you set up a system of grounding rods. Using numerous ground rod connections with solid, smooth wire or copper sheeting will provide the best grounding. Although copper is the best choice, aluminum can be used above ground; however, you should never use it below ground because aluminum is very susceptible to corrosive elements in the dirt. A ground wire can vary in size from (#4 up to 4/0). Run bare copper between the separate ground rods to form a ground system. Bare copper wire provides added surface contact area for the ground system. It should be laid underground between connecting rods.
Tip: Draw a detailed map of the buried cable runs to avoid hitting or digging up the system in the future. For maximum affect this run must be less than nine feet. Be sure to properly research what size material you need based on your equipment grounding needs.
Surge Grounding protects against an unexpected surge in electricity. This is often times caused by a lightning strike. When lightning strikes a power line some distance away, the massive jolt of electricity will cause a surge or electronic shock wave to travel down the wires to your home and potentially all electrical components inside its walls. Since lightning strikes cannot be predicted, it is imperative that you ground your equipment properly when you first install your equipment. If you take the “install now, ground later” approach, an untimely storm could take your ham radio ambitions back to the starting line.
Storm's Ham Radio grounding kit
An additional benefit to a proper surge ground is protection from static build-up, which can sometimes zap the user or harm equipment. A surge, or safety ground, should have enough surface area contacting the earth to dissipate the surges safely.
Lightning can be a frequent and unwelcome visitor to tall towers. The height of these structures often require a large-area ground with low impedance in addition to a wide, smooth copper flashing or heavy gauge solid wire surrounding critical areas. These critical areas would include a work area or equipment area near the base of the tower. Tall towers need a ground which will spread an electrical charge out over a wide area, rapidly and evenly. The goal is to prevent the voltage in objects near a structure from rising significantly faster than other objects located near the tower. When lightning strikes, very high currents can flow between objects near a tower, therefore, it is important to provide a low-impedance path for these currents.
Lightning grounds should always provide a common low impedance path between everything conductive entering a building. This means power lines, telephone lines, TV antennas, and metallic conduits or pipes should all share a common ground connection buss that has very low impedance. Normally the lowest impedance connection is provided by a wide smooth surface copper flashing, although very heavy round copper can be used. Round copper has lower RF resistance per unit length for a given surface area, but flat wide copper has less reactance and lower overall impedance. This is because fewer magnetic flux lines encircle any given area of wide strip than enclose the surface area of a compact conductor. In effect the magnetic field is “spread out”, reducing inductance.
You can order the Ham Radio Grounding Kit, or the Ham Radio Grounding Kit with Call Letters engraving online at Stormcopperstore.com, or contact our customer service staff at 888-334-2177.