#1 Mistake Hams Make During Thunderstorms—Fix It Before It's Too Late

Lightning Protection for Ham Radio: Grounding, Bonding, and Disconnecting Done Right

Every summer, radio forums fill with the same stories: damaged transceivers, burned coax switches, failed tuners, and operators wondering why their “lightning protection” did not work.

Lightning protection is one of those topics where amateur radio folklore can become dangerous. Disconnecting coax, putting a plug in a glass jar, adding a random ground rod, or relying on a single surge protector may feel reassuring, but none of these are complete protection systems.

The uncomfortable truth is simple: no amateur station can be guaranteed safe from a direct lightning strike. The goal is risk reduction. A good installation gives surge energy a better path than through your radio, your shack, or your house wiring.

The Glass Jar Myth

Let’s start with the classic one: disconnecting your coax and placing the connector in a glass jar.

This may prevent the connector from touching your desk, but it is not lightning protection. A lightning surge can jump through air, flash over surfaces, arc to nearby wiring, damage equipment through other connected cables, or enter through the shield if the feedline is not properly bonded before it enters the building.

Disconnecting antennas can still be a good habit, but it should be treated as an extra precaution, not the main protection method.

The better approach is to stop surge energy at the station entrance, bond it to a proper grounding system, and keep it outside as much as possible.

Grounding Alone Is Not Enough

Many operators think lightning protection means “install a ground rod.” That is only part of the story.

A ground rod by itself does not make a station safe. In fact, a separate unbonded ground rod can make things worse by creating a large voltage difference between your radio ground, antenna ground, and household electrical ground during a surge.

A useful lightning protection system is based on three things:

• Bonding: all grounds and metal paths must be connected together so they rise and fall together during a surge.
• Low-impedance paths: conductors should be short, straight, wide where practical, and free of sharp bends.
• Surge control at the entrance: coax, rotor cables, control lines, Ethernet, and other incoming cables should be protected and bonded before they enter the shack.

For lightning, the word “impedance” matters more than simple DC resistance. A long, thin, coiled, or sharply bent wire may measure low resistance with an ohmmeter, but still present a poor path to a fast lightning impulse.

RF Ground Is Not Lightning Ground

This point is important: an RF ground and a lightning protection ground are not the same thing.

An RF ground, radial field, counterpoise, or antenna return system is designed to improve antenna behaviour. It may help with feedpoint impedance, return current, common-mode current, or radiation efficiency.

A lightning protection system has a different job. It must reduce dangerous voltage differences and provide a controlled path for surge current. That means bonding the antenna system, mast, coax shields, entry panel, equipment ground, and building grounding electrode system together according to local electrical rules.

A radial system under a vertical may be excellent for RF performance, but it should not be assumed to be a complete lightning protection system.

Use a Single-Point Entry Panel

One of the best station practices is to bring all antenna and control cables to a single entry point before they enter the building.

At that entry point, install a grounded metal panel or bulkhead. This is where coax shields, lightning arrestors, grounding blocks, rotor cables, and control-line protectors are bonded to the external grounding system.

The idea is simple: if surge energy arrives on a cable, it should be diverted to the grounding system at the wall, not after it has already travelled across the shack desk.

A good entrance system usually includes:

• coaxial lightning arrestors or surge protectors mounted directly on the entry panel
• bonding of coax shields to the panel
• protection for rotor, relay, remote tuner, amplifier keying, Ethernet, and control lines
• a short, straight bonding conductor from the entry panel to the grounding electrode system
• bonding to the building electrical grounding system to avoid dangerous voltage differences

Do not protect only the coax and forget the rest. Lightning energy can enter through any conductor connected to outdoor equipment.

Ground Rods, Conductors, and Materials

Ground electrodes should follow local electrical code. Depending on your region and installation, this may involve copper-bonded ground rods, ground rings, foundation earth electrodes, buried conductors, or other approved electrodes.

For a ham station, the exact details depend on soil, building layout, local regulations, tower or mast height, cable routing, and whether the station is inside the house, garage, shed, or outbuilding.

As general principles:

• use conductors that are physically robust and suitable for outdoor bonding
• keep lightning bonding conductors short and straight
• avoid coils, loops, sharp bends, and long indoor ground wires
• use wide copper strap or heavy bonding conductor where appropriate
• use proper clamps and corrosion-resistant connections
• bond all grounding electrodes together; do not create isolated ground rods

Copper and copper-bonded steel are commonly used because they combine good conductivity with practical mechanical strength. Stainless steel has higher electrical resistance than copper, so it should not be chosen casually as a lightning conductor just because it survives weather well. Use materials that are approved for the job and compatible with the rest of the grounding system.

Lightning Arrestors Are Not Magic

Gas discharge tubes, coaxial arrestors, and surge protectors are useful, but they are not magic parts that absorb lightning and make it disappear.

A surge protector only works properly when it has a short, low-impedance path to the grounding system. A coax arrestor screwed into the back of the radio, with no proper ground connection, is not real lightning protection.

The correct place for surge protection is usually at the cable entry point, bonded directly to the station entrance ground panel.

What About DC-Open Antennas?

Many common antennas are DC-open at the feedpoint. Examples include some centre-fed dipoles, fan dipoles, end-fed arrangements, loops with capacitive coupling, and antennas using certain matching networks.

A DC-open antenna can accumulate static charge from wind, rain, snow, nearby thunderstorms, or charged particles in the air. This can cause static crashes, small arcs, receiver noise, or damage to sensitive front-end components.

A static bleed path can help with this. Depending on the antenna type, this may be done with a high-value resistor, RF choke, transformer winding, static drain, or suitable surge component.

However, this must be designed carefully. A random resistor across a feedpoint is not always harmless. At high-impedance points, such as some end-fed antennas, RF voltage can be very high. The bleed component must have suitable voltage rating, power rating, weather protection, and RF behaviour.

A static bleed resistor is not lightning protection. It helps with static buildup, not direct strike energy.

Disconnecting Still Has Value

Disconnecting antennas before a storm is still a good habit, but it should be done correctly and before the storm arrives.

Do not handle antenna cables during active lightning. If thunder is nearby, it is already too late to safely work on outdoor cables or grounding switches.

A better station setup uses a grounded coax switch, grounding bar, or external entry panel so feedlines can be bonded to ground when the station is not in use. Ideally, disconnected feedlines should be grounded at the entry point, not left loose inside the shack.

Disconnecting the radio from coax is helpful. Disconnecting the radio from power, control cables, computer interfaces, audio cables, Ethernet, rotator lines, and amplifier lines may also matter. Surge energy often finds the forgotten cable.

A Practical Station Checklist

For a safer amateur radio station, think in terms of a complete system:

• bond the mast, tower, antenna support, and coax shield
• bring all feedlines and control cables to a single entry point
• install coaxial surge protectors at the entry panel
• protect rotor, relay, tuner, Ethernet, and control lines too
• use short, straight, low-impedance bonding conductors
• bond the station ground to the building electrical grounding system
• avoid isolated ground rods
• use static bleed paths where appropriate, especially for DC-open antennas
• disconnect equipment before storms when practical and safe
• follow local electrical code and consult a qualified professional for towers, rooftop antennas, or complex installations

Bottom Line

Lightning protection is not about rituals. It is about controlling where surge current flows and reducing dangerous voltage differences.

A glass jar does not do that. A random ground rod does not do that. A coax arrestor with no real bond does not do that.

A good system uses bonding, a proper grounding electrode system, a single-point cable entry, surge protection at the entrance, static bleed where appropriate, and safe disconnection habits.

Grounding matters. Bonding matters more. And nothing replaces a well-planned station entrance.

Interested in more technical content? Subscribe to our updates for deep-dive RF articles and lab notes.

Questions or experiences to share? Feel free to contact RF.Guru for practical RF and antenna support.