Radio Antenna Tower and Lightning

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Chevyman22360

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I have a Rohn HDBX 64 foot self supporting tower. I have it just on the north side of my house, I am very concerned about lightning and what it can do. I am considering taking 3 sections off, as it will just be above the house at that point. I am wondering if this will help my chances as far as getting struck? I don't need the height as I have good line of sight of what I want to hear. I have all my coax's grounded before coming into the house. Any ideas?? Thanks in Advance
 

Wahoos4Life

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I have a Rohn HDBX 64 foot self supporting tower. I have it just on the north side of my house, I am very concerned about lightning and what it can do. I am considering taking 3 sections off, as it will just be above the house at that point. I am wondering if this will help my chances as far as getting struck? I don't need the height as I have good line of sight of what I want to hear. I have all my coax's grounded before coming into the house. Any ideas?? Thanks in Advance

making it lower would probably lower your chances , but it can still get struck
 

hoser147

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I would go for the height and leave it like it is. There are several threads and the Wiki that have info on lightning strikes and how to protect you home and equipment. Good Luck
 

buddrousa

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One of the best things you can do is put a ground rod beside you tower and ground the tower. Also unless you are on top of a mountian and have no trees taller than your tower I would not worry.
 

donc13

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I have a Rohn HDBX 64 foot self supporting tower. I have it just on the north side of my house, I am very concerned about lightning and what it can do. I am considering taking 3 sections off, as it will just be above the house at that point. I am wondering if this will help my chances as far as getting struck? I don't need the height as I have good line of sight of what I want to hear. I have all my coax's grounded before coming into the house. Any ideas?? Thanks in Advance


Think about this.....lightning jumps through perhaps a mile of air (an insulator)...and you think taking 3 sections of tower down will help? Sure, lightning, like all electricity, takes the easiest path to ground but when you consider the (what are they, 10' sections?) 30 foot lowering of height of the antenna is really not changing how easy it is for lightning to get to ground.

What you MUST do, is properly ground your tower. So if it does get hit by lighting, that the energy is harmlessly dissipated in teh ground.

I put in a 30' tower at my old house. The base was set on gravel (so water could drain from the legs) and then set in concrete and a stabilizer arm was attached to the side of my house. Other than that...it was freestanding. I live in Colorado....thunderstorm alley (Denver metro area). I used 3 10' copper ground rods, hammered in to the ground OUTSIDE the concrete plus I had a 4th ground rod in the center of the antenna that was hammered into the ground before the concrete was poured.

Each leg of the tower had a heavy ground strap to the center ground rod and one of the outside ground rods. They were 'bonded' using standard electrical ground rod clamps. All the coax (I had about 5 antenna on the tower) had grounding adapters at the base of the tower that were on a sheet metal "plate" I had brazed to one side of the tower.

I'd say, that tower got hit once or twice a year (and there was a much taller tree on the other side of the house...it never got hit that I know of).....and NOTHING happened. Proper grounding 'saved' the day as it is intended to.

So yes....no matter what else you do...make sure the tower itself is WELL grounded. Maybe I went a bit overboard....but maybe not....whatever, it worked.
 

ratboy

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I have been, or should I say, my equipment has been directly hit 3 times by lightning. The first time, was about 30 years ago, in Las Vegas. If you have ever been there, you know they have insane amounts of rain a couple times a year, and I had a 30ft tower up in my backyard, with a Shakespeare "Super Big Stick" on top, and a ground plane scanner antenna on a stand off. I had a small mobile CB connected with RG58 coax. The storm hit while I was gone, and I came home and wasn't thinking about it until a minute before it hit. I was in the room next to where the CB was, and suddenly, there was a big bang, and a flash. The CB, power supply and my new SWR meter were smoking, and totally destroyed. Outside, it was raining fiberglass. All the IC's inside the CB had their tops blown off, and inside them was.. nothing.

The second time was back in Ohio, and another Big Stick got hit, and again, there was fiberglass all over the neighborhood, but I got off cheap since only the antenna and coax were zapped.

The third time, there was a tremendously loud bang, and my satellite reeceiver had been hit, destroying it. It was a replacement for one that had ben zapped by a near hit a few months before.

I have had several surges, destroying things from modems to UPS's, to an old Pro-2022 scanner, to a phone. I live within about a 1/4 mile of a large river, and even closer are several high tension towers, so there are better targets for it to hit, but I still have at least one near miss a year that does something.
 

Scott_PHX_APP

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I have been, or should I say, my equipment has been directly hit 3 times by lightning. The first time, was about 30 years ago, in Las Vegas. If you have ever been there, you know they have insane amounts of rain a couple times a year, and I had a 30ft tower up in my backyard, with a Shakespeare "Super Big Stick" on top, and a ground plane scanner antenna on a stand off. I had a small mobile CB connected with RG58 coax. The storm hit while I was gone, and I came home and wasn't thinking about it until a minute before it hit. I was in the room next to where the CB was, and suddenly, there was a big bang, and a flash. The CB, power supply and my new SWR meter were smoking, and totally destroyed. Outside, it was raining fiberglass. All the IC's inside the CB had their tops blown off, and inside them was.. nothing.

The second time was back in Ohio, and another Big Stick got hit, and again, there was fiberglass all over the neighborhood, but I got off cheap since only the antenna and coax were zapped.

The third time, there was a tremendously loud bang, and my satellite reeceiver had been hit, destroying it. It was a replacement for one that had ben zapped by a near hit a few months before.

I have had several surges, destroying things from modems to UPS's, to an old Pro-2022 scanner, to a phone. I live within about a 1/4 mile of a large river, and even closer are several high tension towers, so there are better targets for it to hit, but I still have at least one near miss a year that does something.

Ratboy,
Say, where do you live now? I want to be sure I'm far enough away from you if I put something up in the air. :D :D OK< maybe it's better to live close to you, you seem to be the site of choice? :D :D
To the OP, GROUND, GROUND and did I mention GROUND!? :)
Later...
 
K

kb0nly

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Another vote for GROUND!! Put in at least one ground rod and attach to tower, if you can put three in and attach one to each side of tower, that makes up for poor ground conditions having more than one ground rod as well.

I got one ground rod in for each tower, i was going to put more in but the ground froze before i had time to work on it. Spring comes and i will be further improving the ground system. Oh, and you can click on my web address below and have a look at the pictures of the towers and the grounding.
 

Chevyman22360

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Another vote for GROUND!! Put in at least one ground rod and attach to tower, if you can put three in and attach one to each side of tower, that makes up for poor ground conditions having more than one ground rod as well.

I got one ground rod in for each tower, i was going to put more in but the ground froze before i had time to work on it. Spring comes and i will be further improving the ground system. Oh, and you can click on my web address below and have a look at the pictures of the towers and the grounding.

Where did you get that grounding and utility box? Did it come with the contents, also what size grounding braid do you have there?
 

Allan_Love_Jr

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Arlington, Nebraska
I have been, or should I say, my equipment has been directly hit 3 times by lightning. The first time, was about 30 years ago, in Las Vegas. If you have ever been there, you know they have insane amounts of rain a couple times a year, and I had a 30ft tower up in my backyard, with a Shakespeare "Super Big Stick" on top, and a ground plane scanner antenna on a stand off. I had a small mobile CB connected with RG58 coax. The storm hit while I was gone, and I came home and wasn't thinking about it until a minute before it hit. I was in the room next to where the CB was, and suddenly, there was a big bang, and a flash. The CB, power supply and my new SWR meter were smoking, and totally destroyed. Outside, it was raining fiberglass. All the IC's inside the CB had their tops blown off, and inside them was.. nothing.

The second time was back in Ohio, and another Big Stick got hit, and again, there was fiberglass all over the neighborhood, but I got off cheap since only the antenna and coax were zapped.

The third time, there was a tremendously loud bang, and my satellite reeceiver had been hit, destroying it. It was a replacement for one that had ben zapped by a near hit a few months before.

I have had several surges, destroying things from modems to UPS's, to an old Pro-2022 scanner, to a phone. I live within about a 1/4 mile of a large river, and even closer are several high tension towers, so there are better targets for it to hit, but I still have at least one near miss a year that does something.
Holy crap. Your a damn magnet for Lightning.
 
N

N_Jay

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Find a copy of Motorola's R56 and follow as much of it as practical.

It is not perfect, but it is about the best thing out there.
 

petey_racer

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Sure, lightning, like all electricity, takes the easiest path to ground.......
I have to laugh when I hear this. it is such an old wives tale and SO untrue.
Lightning is an anomaly. It does what it wants. It doesn't always strike the highest thing and it is never predictable.

Electricity on the other hand is absolutely NOT "seeking ground". It is seeking it's source, namely the transformer in most cases.
The fat that most parts of the system are connected to the earth make the earth a path back to the source. A really POOR path, but a path nonetheless.
 

hoser147

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Chevyman, Its quite possible that your tower and antenna already have a Ground system installed. You need to take a look and see what you already have before you can proceed any further. If its like here this morning Cold your going to want to wait till the weather breaks and you can see exactly what you have...
 

donc13

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I have to laugh when I hear this. it is such an old wives tale and SO untrue.
Lightning is an anomaly. It does what it wants. It doesn't always strike the highest thing and it is never predictable.

Electricity on the other hand is absolutely NOT "seeking ground". It is seeking it's source, namely the transformer in most cases.
The fat that most parts of the system are connected to the earth make the earth a path back to the source. A really POOR path, but a path nonetheless.

Lightning has nothing to do with transformers other than it hits them now and then.

I never said it hit the highest thing...in fact I noted that lightning didn't hit a high tree near my tower, it hit the tower. It takes the easiest path to GROUND.

Common terminology is that "ground" is the return path...whether it is physical ground, or a wire with a lower electrical potential is of no consequence.

In the case of lightning the base of a cloud collects a negative charge, relative to the physical ground or the top of another cloud (or even the same cloud). The easiest ELECTRICAL path to neutralize those charges is the path taken by lightning. However, because ionization of the air plays a signifigant role in that pathway....you are correct, you can not predict where exactly lightning will strike.
 

davidmc36

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you can not predict where exactly lightning will strike.
Just like the young girl playing soccer that was in the news a year or two ago. There were no storms for miles around and all of a sudden, BLAMMO! Killed her on the spot IIRC, and injured several others. It was clear and sunny. The lightning travelled for miles to find the easiest path to GND.
 
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kb0nly

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Where did you get that grounding and utility box? Did it come with the contents, also what size grounding braid do you have there?

The grounding/utility enclosure is from:

www.dxengineering.com

It comes with the aluminum plate inside, and it comes with the watertight bushings that you install into the top of it but thats it. All the other stuff was bought seperately, the gas arc lightning arrestors for the coax and the big box to the left of them is the ICE Radio Products arrestor for the rotor cable and the cable to the remote antenna switch box. The stuff inside the front cover is the junction box and inline arrestor for the Davis weather station.

The coaxial arrestors are from Jetstream:

http://jetstream-usa.com/jt40r.shtml

They are available from:

www.randl.com

Now i know someone is going to jump in and suggest the Polyphaser units instead, go for it, i hate them. After seeing them fail without taking the full surge to ground or manufacturing defects inside i won't pay four times as much for one of them. The Jetstream models, which are identical in construction to the ones Diamond and MFJ sell that look the same, cost less than $20 a piece. I'm not saying they are better or perfect, but its better than nothing and affordable.

I would love to be able to afford the ICE Radio Products models, we have them on the repeaters around here, they have a constant drain to help combat static buildup and there has been documented cases where they take a direct tower strike and the contents of the box sound like a baby rattle but the attached equipment is fine.

Here is their website..

http://www.iceradioproducts.com/impulse1.html#1

As for the ground braid on the towers its just some stuff i found at a hamfest, its tinned copper and about an inch wide by 1/8' thick. You can go to some auto parts stores and find similar flat ground straps, sold as a body or engine block ground strap. I have a local stereo shop that has this ground braid in rolls, they use it to ground the hoods and exhaust on vehicles to eliminate all traces of engine noise in the audio.
 
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ratboy

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Holy crap. Your a damn magnet for Lightning.

Sometimes I think so, but I know other people who have had similar "contact" with it.

But I don't know anyone who has seen "Ball Lightning" but me. Destroyed two TVs in two seperate hits.

One of the neatest things I ever saw.
 

crazyboy

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You need to have a common ground amongst everything in the structure for it to work properly!
 

ratboy

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Ratboy,
Say, where do you live now? I want to be sure I'm far enough away from you if I put something up in the air. :D :D OK< maybe it's better to live close to you, you seem to be the site of choice? :D :D
To the OP, GROUND, GROUND and did I mention GROUND!? :)
Later...

I live in NW Ohio, and I'm way past due for a hit actually. I have 3 ground rods, two shorter ones on both sides of my tower, and a 10' one outside my window. I have surge protectors on all the lines coming in.
 
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