plasmas inside your house. True, the radio may still work, if it survives the house fire. Throwing the coax out the window is not a solution, especially if the coax has already entered the house from the antenna or the antenna is roof mounted without a ground path. Grounding switches will not last long with direct hits unless other good ground paths are provided. Grounding the antenna line and not disconnecting the coax shield can still allow strike energy to be shared with the equipment The shield connects to chassis and if a single point ground is not present with power/telephone protectors, the equipment will be damaged.

Full protection for a ham shack must cover not only strikes to your tower, but also hits from down the road to utility lines. By using single point grounding, your ham equipment will survive the hit to your tower. If the outside (tower/perimeter) ground has a low impedance, most of the strike energy will be dispersed into the ground and little energy will enter the shack. This is fine, but what if your ground has deteriorated over time or was never very good because of yard size?

The ground system can absorb only so much energy before it becomes saturated. In 90% of the strikes, a traffic jam of electrons will be coming down your tower. If they can not spread out in a reasonable time frame, the back up pressure (voltage) will find or create another path. The ground system, if too small in area, will cause more energy to traverse the cables and other lines to the shack. The I/0 protectors can keep the voltage levels between the single point ground and the signal line(s) at survivable limits, but the energy is only diverted elsewhere. This could be the house phone lines and power lines.

Other house appliances may be at risk. When the ground system is saturated, the energy is actually coming from the (utility) ground system and can go through your TV, for example, in an effort to leave the area by way of the cable TV drop. Satellite dishes will also have the same problem. The best way to protect the rest of the house is to provide protection at a single point. The easiest single point will be at the power and telephone entrance. The utility ground rod (which should have been already interconnected to your ground system) is used by both the power neutral and the telephone protector installed by the phone company. By placing a power mains protector and a secondary phone line protector at this location, the entire house will be protected.

The cable TV or outside antenna coax should be rerouted and a good coaxial protector installed at this point. The cable company installed protector is usually just a grounding block which will earth only the outside shield and does nothing to the center conductor energy which can have as much energy as the outside shield! As the ground system rises in potential from a strike, the protectors will take the ground system energy and place it on the power, telephone, and cable TV lines while keeping the voltages between earth and the active lines within the limits of equipment survival.

The utility ground rod for the house should have already been interconnected to your ground system. What if this can’ t be done? If this is not done, the energy from the tower strike will traverse the house safety ground wires to this rod, causing problems. The reason to interconnect them in the ground using bare conductors was to reduce the inductance of the interconnecting path. It is true that the house wires are a parallel path and there is nothing we can do about it. If the interconnect path is better (lower inductance and resistance) the majority of the current will bypass the house wiring. The only alternative is to provide a copper strap path through the house. This may not be a sufficiently low inductance path and it will radiate to other wires/equipment inside the house.

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