LIGHTNING PROTECTION

First of all there is no such thing as complete lighting protection. All a Ham can do is provide the highest level of protection as possible. Depending on your location, lighting may be a very common occurrence (especially in summer) or a very infrequent occurrence. For example, the Mid West and East Coast have frequent thunder storms during the summer months while California has very few throughout the year. But all areas have thunder storm now and then. Not all thunder storms have rainfall but that is not what we are interested in anyway. We are concerned with the damage potential of either an indirect or a direct lighting strike.

An indirect strike is simply a strike, for example, that hits a nearby power line and then feeds into your equipment. A direct strike, for example, might directly hit your tower, come down the feedline and destroy equipment. Fires can start from both indirect and direct strikes. The chance of major damage and/or a fire is a little less with indirect strikes. But none-the-less, we all have to be vigilant about lighting.

The first and foremost method of reducing the risk of lightning damage is proper grounding. A good ground should be as short as possible between the equipment and ground. On the other hand, the buried ground wire and/or pipe should be a good conductor in itself and as long or deep as possible. The ideal ground would use a copper pipe driven 10 feet or more into the ground. This is not always practical. If you live in a area where the soil is very rocky then driving a copper pipe more then a foot or two into the ground may be nearly impossible. An alternative to this might be 4 or more shorter copper pipes driven into the ground a few feet apart. You could then tie the pipes together with heavy gauge copper wire. If you are able to dig a trench, say 24" deep and 100 feet long you could also bury heavy gauge copper wire in it for either a ground or to supplement copper pipes driven as deep as possible, The key here is to get a much copper in the ground as possible and as close to moisture (for improved conductivity) as you possibly can.

Now when we talk heavy gauge, what do we mean? Some might consider 14 gauge copper wire heavy duty. Others might think it take at least 2 gauge or more. The rule to follow is to buy the largest copper wire you can afford. Keep in mind that if lighting strikes, you may not be able to only afford 10 gauge wire. It would be best to use at least 8 gauge wire but 6, 4 or even 2 gauge would be better.  As for the size of copper tubing, again purchase the largest diameter you can afford, up to a point. For example, even if you could afford a 12 foot piece of 6" copper pipe, you might not be able to get it into the ground with damaging it.

What about lightning arrestors?

These are very good ideas, but only if they are installed properly and are of a high quality. My choice is those with gas discharge tubes in them. I also prefer the type that use type N connectors and not UHF connectors. Actually, I dislike UHF connectors anyway. For one, they are not waterproof like an N connector. These also introduce a mismatch since they are not 50 ohms. This is not much of a problem on HF though.

One suggestion with lightning arrestors; don't buy them used. If they have actually been "used" they may offer no protection at all. Other things that need to be considered before purchase is their ability to handle the power of your station. If you run 1500 watts on 2 meters and your lightning arrestor is only rated for 100 watts at 30 MHz, you have a problem. Also look at the different choices and check the loss numbers. No use giving up half your received and transmitted signal in a lightning arrestor. The better quality products offer a couple tenths of a dB loss at their design frequency.

Place the lightning arrestor as close to the point where the cable either enters the ground, or the shack, whichever comes first. For example, if you use direct burial cable, you might place the arrestor near the antenna, or at the base of the tower. On the other hand, if you have a run of coax laying on the ground that runs, say 50 feet, and then enters the shack, I would place the device near the point of entry.

As I discussed above, low impedance grounds are a must here. A 24 gauge wire that runs 20 feet to a 3 foot ground rod will offer nearly zero protection. Go back to the top and read the section on ground rods and wires again. Everything I said there applies here. DON'T SKIMP on your ground rods and connections. Big, many, heavy, are good words to apply. Even in areas that do not get frequent thunder and lightning storms. All it takes is one strike.

You can obtain additional information from the National Lighting Safety Institute from their web site. To go there Click Here Now.

For even more information go to this National Weather Service web site.

WHEN LIGHTNING STRIKES

Find shelter immediately! If you're unable to find shelter consider the following:

Indoors

Stay away from windows, doors and electrical appliances and plumbing fixtures

Unplug appliances before a storm approaches; not during the storm

Do not use the telephone except for emergency

Outdoors

Go to a shelter equipped with a lightning protection system such as found at golf courses, in some public parks and swimming pools

If you're caught outside and are unable to get inside a building then:

Sit in a car

Stay away from trees and other tall objects by a distance of at least twice their height

Avoid areas that are higher than anything else around

Stay far away from metal objects

Immediately get out of water if you are swimming or boating

Spread out - don't stand in a large group of people

If you feel a tingling sensation and/or your hair stands on end, a lightning may be immanent! Immediately crouch down on the ground and cover your ears. Don't lay on the ground or put your hands on the it

If after taking all possible precautions and lightning does strike nearby, or even directly, make certain that any injured people receive first aid assistance including CPR if necessary. Then seek medical attention immediately.

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