Station grounding guide
RF grounding, safety grounding, and lightning protection for amateur radio stations. What to ground, how to ground it, and why.
Station grounding for RF performance, electrical safety, and lightning protection.
Three types of grounding
Amateur radio stations deal with three distinct grounding needs. Confusing them causes problems.
1. Electrical safety ground (NEC / building code)
This is the green wire in your outlet. It protects you from electrocution if equipment develops a fault. Your radio equipment must be connected to the building's electrical safety ground through properly grounded outlets. This is code, not optional.
What to do: Plug your equipment into properly grounded outlets. If your shack uses extension cords (it should not), ensure the ground pin is connected. If your building has old two-wire wiring, hire an electrician.
2. RF ground
RF grounding provides a low-impedance path for stray RF currents that would otherwise flow through equipment chassis, computer cables, and your body. RF grounding is why operators who run amplifiers without a good ground get RF burns from their microphone.
What to do: Connect a short, wide copper strap (not wire — strap) from your station ground bus to an external ground rod or cold water pipe. Short means under 10 feet. Wide means 2-3 inches of copper strap, not a thin wire. At HF frequencies, inductance matters more than resistance, and a wide strap has lower inductance than a thin wire.
The ground bus: A copper bar or strip mounted behind the operating position. Every piece of equipment connects to the ground bus with short copper straps. The ground bus connects to the external ground with a single wide strap.
3. Lightning protection
Lightning protection prevents a strike on the antenna from entering the shack. This is separate from RF grounding and electrical safety grounding.
What to do: Install a single-point ground panel at the point where coax cables enter the building. Every coax cable passes through a lightning arrestor (PolyPhaser, Alpha Delta, ICE) mounted on the ground panel. The ground panel connects to a dedicated ground rod with the shortest possible heavy copper conductor (4 AWG or larger). The antenna system ground rod bonds to the building electrical ground rod with a bonding conductor (6 AWG minimum).
Critical: All ground rods must be bonded together. Separate, unbonded ground rods create a voltage difference during a lightning event that is more dangerous than no grounding at all.
Common mistakes
Using a thin wire instead of a wide strap for RF ground. A 20-foot piece of #12 wire has enough inductance to be useless as an RF ground on 20 meters. Use wide copper strap, keep it short, and avoid sharp bends.
Separate unbonded ground rods. The shack ground rod and the electrical service ground rod MUST be bonded together. NEC code requires this. Unbonded grounds create a potential difference during lightning events.
Relying on the electrical safety ground as an RF ground. The green wire in your outlet is not an RF ground. It may be adequate for safety but it is not low-impedance at RF frequencies.
No lightning protection. If your antenna is the highest point on the property, it will eventually take a lightning hit. The question is not if but when. Lightning arrestors on every coax line entering the building are the minimum protection.