Grounding and Lightning Protection
Setup & Programming
Grounding your antenna system serves three purposes: protecting your equipment from lightning damage, reducing electrical noise, and improving antenna performance. A proper ground isn't optional if you have an outdoor antenna — it's essential.
Why grounding matters
- Lightning protection: an outdoor antenna is the highest point on most homes. Even a nearby lightning strike can induce thousands of volts on your coax and power lines. A good ground gives that energy a safe path to earth instead of through your radio
- Noise reduction: electrical noise from appliances, motors, and power lines can interfere with reception. A solid ground reference helps your radio reject this noise
- Antenna performance: many vertical antennas rely on a ground plane to work efficiently. A proper ground improves the antenna's radiation pattern
Ground rod installation
The foundation of your station ground is a copper-clad ground rod driven into the earth near where the coax enters your building.
- Use an 8-foot copper-clad ground rod (5/8" diameter minimum). Available at hardware stores
- Drive it into the earth as close to the antenna feedline entry point as practical
- The National Electrical Code (NEC) requires that your antenna ground rod be bonded to the building's electrical service ground. This is critical — two separate ground systems at different potentials can actually be more dangerous than no ground at all
- Use #6 AWG copper wire or larger for bonding between ground rods
Important: Your antenna ground rod must be bonded to your home's main electrical ground. If they are not connected, a lightning strike could create a voltage difference between the two ground points, sending current through your house wiring and equipment. A short run of heavy copper wire between the two ground rods satisfies this requirement.
Lightning arrestor (polyphaser)
A coaxial lightning arrestor installs inline with your coax cable at the point where it enters the building. It passes normal RF signals through but shunts high-voltage surges to ground. Install it on the outside wall, connected directly to the ground rod with a short, straight run of heavy copper strap or wire.
- Choose an arrestor rated for UHF/GMRS frequencies (462-467 MHz)
- Mount it at the building entry point — before the cable comes inside
- Use the shortest possible ground wire from the arrestor to the ground rod. Long ground wires have inductance that reduces their effectiveness
- Keep the ground wire straight — no sharp bends or coils
Station grounding
Inside the shack, connect the chassis of your radio and power supply to the ground system. Many radios have a ground lug on the back panel for this purpose. Use heavy copper braid or strap to connect the radio and power supply chassis to a common ground bus bar, which then runs to your external ground rod.
Grounding checklist
- 8-foot ground rod driven near the antenna feedline entry point
- Antenna ground rod bonded to the building electrical service ground with #6 AWG or heavier
- Coaxial lightning arrestor at the building entry, grounded to the rod with short, straight copper
- Radio and power supply chassis connected to the ground system
- All ground connections clean, tight, and corrosion-free