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Large wire-wound resistors are used for static discharge drains on tall towers. Unless you have winds exceeding 20-30 miles per hour and humidity below 20 percent on a consistent basis, adding a static discharge resistor is a waste.
To use the same component for lightning protection is also a waste of time and money. Lightning is super high frequency energy seeking a path to earth. Anything, and I mean anything, in the way will be destroyed. The resistor becomes a fuse. After it burns apart, what happens to the follow strike?
A high current, high inductance choke (several millihenry) would help the most with static discharge. However, the reality is, the Part 15 AM antenna is a “sky-needle” by its very construction. And as such, the higher the antenna in relationship with surrounding terrain, buildings and trees makes more of a difference than anything else.
Equalizing charges would be impossible to accomplish. One potential is in the cloud, the other is on the ground. The build up of a charge in the thunder cloud actually develops the charge on the ground. When the potential on the ground is great enough, the lightning begins on the ground, tree, building, antenna or whatever, and begins to discharge from ground to cloud. The cloud follows by discharging causing the visible lightning bolt.
Here is the smart thing to do. Drive four or five 8 foot ground rods into the ground approx. 8-12 feet apart, covering as much ground as possible. The tops of the rods should be 4-6 inches below ground level. The ground rods should be the copper coated variety, not the galvanized (zinc coated) variety. Connect the ground rods with 3-4 inch wide copper strap (available from a variety of vendors online) using heavy duty bolts or clamps. Use enough strap to connect all the rods and at least two of the tower legs together electrically. This system helps to dissipate and spread the discharge out (it has to handle a HUGE amount of electrical current). Then, you can connect your transmitter ground to the system. Your AM transmitter will still probably turn into a briquet after a strike, but at least you have a chance of not having the house burn down.
Please understand, when it comes to the destructive potential of lightning, there is nothing you humanly can DO to discourage or stop it. Even follow strikes and finger strikes in your vicinity are potentially very dangerous.
Marshall Johnson, Sr.
Rhema Radio – The Word In Worship