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Should I (electrically) ground my TV antenna?

I've heard both: "you must always ground your antenna" and "you don't need to".

I haven't grounded it (at all) yet.

Under what circumstances is it useful or necessary?

I imagine a TV antenna could theoretically be struck by lightning, but I don't know if that's the only reason to ground.

My home is single storey. All 4 of my neighbours within 50m or so have taller antennas. Some have trees twice that tall. A few houses down, there are double storey homes too. My street is lower than surrounding streets and is in a low lying area (does this remove all chance of lightning strikes to my home?).

Grounding is not required by law (where I live).

In my case, would grounding it simply increase the (unlikely) possibility of a lightning strike?

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Having tall structures nearby means absolutely nothing. Lighting will find what it wants and ground through it. Any other suggestions on your part are just wishful thinking. A teenager was killed near here by direct lightning strike while standing in his front yard. The lightning failed to strike the 70 foot trees on the property perimeter, the antenna on the chimney, the chain link fence or any other structure taller than 5.5ft. It also missed the nearby mountainside that rises behind the property. There are a lot of things lightning will miss in its mile or more distance of travel. –  Fiasco Labs Aug 18 '13 at 3:46

5 Answers 5

up vote 8 down vote accepted

Yes, you should have a grounding block wired to a ground rod before the antenna wire enters your home. It won't necessarily prevent all damage from a direct lightning strike, but it will help.

NEC in the States (NFPA 70) says that if you don't ground the grounding box to the same ground rod that is connected to your breaker box, you need a #6 wire between the ground rods. Obviously, that doesn't apply in your locale, but it's still a good idea.

YMMV, but I get excellent digital TV reception from an antenna mounted in my attic. Removes all the worries about grounding, wind, etc.

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Grounding is always important. It won't help much with a direct lightning hit, but you don't need a direct hit to induce damaging energy. –  shirlock homes Mar 9 '11 at 10:59
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Definitely YMMV on the reception. With analog, simple rabbit ears were fine. After the digital switch they weren't anymore. Tried the big antenna in the above garage space first, was only marginally better. Had to give up and install a 30 foot tower, and the signal still flakes out on really windy days. Don't skimp, get the biggest antenna and tower you can, even if you live in the city (like I do)! –  Brian Knoblauch Mar 10 '11 at 14:27
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Thanks. I asked this somewhere else too and was told that not grounding the antenna could result in static charge buildup and actually increase the likelihood of a strike - this was what actually convinced me to do it in the end. –  MGOwen Apr 18 '11 at 23:51

The exact path lightning takes is going to generally be the one of least resistance, so if I follow your logic, you're thinking that by grounding it, you're lowering the resistance and thus increasing the likely-hood of a lightning strike.

I think the reality is, if lightning is going to hit your house, it is going to hit your house. By grounding your antenna, you're not going to divert a strike that would have otherwise gone to your neighbour's house, and likewise, the fact that they have a grounded antenna and you don't doesn't mean they're protecting you from a strike. Now, if it was a 300' antenna, that might be a different story, but on the scales we're talking about, I just don't see it.

Now what grounding it WILL do is make it more likely if your property does get hit, it will hit the antenna and follow the ground wire down to ground. Lightning is still looking for the best path to ground. If that happens to be by hitting your TV antenna, following it to the roof, going across some flashing on your roof to an attic-mounted fan, and then through your electrical wiring, that's how it will go. It could be down the side of a rain gutter, across the telephone wiring and down the utility pole. Point is, you are much better to have it go through the path you created than to have it find its own way.

Keep in mind, though for normal wiring/electrical purposes we would consider materials like asphalt shingles, wood, and plastic to be insulators, when you're talking about the 10 to hundreds of megavolts that lighting has, all those materials are conductive (metal is just a better conductor).

I think you're safer to have it grounded. Just be sure to install decent surge protection on the cables coming in (make sure the coaxial line from the antenna goes through a surge protector).

Frankly, it's a good idea to have surge protection on any sensitive electronics anyways. Even if lighting strikes your neighbour's house or a utility pole, there's a good chance you will at least have voltage spikes on your power/phone/etc lines that can damage anything plugged into them.

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Wrong! (Wish I could down vote) Grounding is meant to prevent strikes. If there are pointy bits on the antenna, electrons get crowded at the points and "boil off" creating a negatively charged field that lightening will avoid. Making a path of "of least resistance" has less to do with guiding the strike (good luck - the lightening will make plasma of most heavy wires), than it does to carry as much current from the ground to the top of your antenna to maintain the negative field. There is such a small potential difference between the ground and top that heavy wire is needed. V=IR! –  Jamie Jul 12 at 1:48

Grounding the antenna will actually help prevent lightning from striking it. During a Thunderstorm, anything conductive that is not grounded, will collect a static charge... as the charge builds up, it'll attract lightning to it. So grounding the antenna, drains off any charge that might build up attracting a strike.

Also an ungrounded antenna, that builds up a charge, can cause silent damage to your equipment, as this charge will discharge down your coax when it builds up a high enough potential, and do 'silent' damage to your TV tuner. You'll just find your TV can no longer tune to any channels. Have you ever heard anyone saying, that after a thunderstorm passed through town, that their TV was no longer working. This can be the cause. It's very important that all antennas and structure wiring be grounded.

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Electricity follows the path of least resistance, as does lightning. Grounding a tower lessens the electrical potential (voltage) between sky and the ground. It does this by providing a stream of electrons to pass through the tower's lightning rod into the sky. It does this anytime the electrical potential is strong enough to move electrons. Even with a benign looking cumulus cloud, the electrons will stream (if they can) through the air and toward the cloud. This stream of electrons may or may not cause lightning to strike the tower and a lightning rod isn't used to direct where lightning strikes. Nope. A lightning rod, or grounded tower, is used to reduce the electrical potential between the cloud and ground. I apologize that I am unable to offer a link to where I have acquired this information; you'll just have to trust me on this one. Providing a stream of electrons is likely to lower the resistance to the cloud about to strike lightning, but some evidence shows that greater charges existing in nearby structures may cause lightning to make a diversion.

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So... should the OP ground their TV antenna or not? –  Niall C. Nov 17 '13 at 2:10

We always sprayed rubberized undercoating (available at any auto parts store) around the base of our antenna poles (the two feet before it goes in the ground). We live in lightning alley and never have had a direct strike in over 46 years and our antenna pole is 50ft tall due to our location.

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OP asked about grounding the pole. Do you spray this rubber coating on the piece that's underground as well, or just the bit that's above ground? –  Niall C. Jul 12 at 5:46

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