Hello Everybody! I'm about ready to set up a base antenna with the mast attached to the eve of my house and I know to connect one end of the ground copper wire to the ground rod; my question: what's the best place to connect the other end? To the bottom of the mast OR inline with the coax with a lightning arrestor? What gauge copper should I use? Thanks in advance for ALL the helpful replies! rockymount622 LSB 38 in Rocky Mount, N. C.
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Grounding a Base Antenna
- Thread starter rockymount622
- Start date
Hi rockymount622! What base antenna are you putting up? You can probably get away with an eve mount and short pole with a Imax or A99, but anything aluminum like a Maco will be too heavy/too much wind load. Preferred method is running a push up pole all the way to the ground, but sometimes that is not feasible. You can run as heavy of gauge wire as you can afford, and run it directly down to the ground to a ground rod. No guarantees that the lightning won't take another path, but you probably already know that.
Another really stout option is a roof mount, but might be overkill for you:
4.5′ Roof-Top Tower RT-424 | GlenMartin
73,
RT307
Another really stout option is a roof mount, but might be overkill for you:
4.5′ Roof-Top Tower RT-424 | GlenMartin
73,
RT307
You know, you should really learn something about proper grounding techniques and stop thinking that just because you have never been hit that your way of doing it is better. You have been lucky. No more and no less. You and a couple others here seem to think that grounding an antenna makes it a lightning rod and more susceptible to lightning strikes and that not having a ground is better. If that was truly the case commercial installations would not spend thousands of dollars on grounding. That fact that they do and take several strikes a year and yet somehow manage to remain on the air proves they are doing it right. If this sounds like I am pissed a bit it is because I am. Having been in radio for 35 years and commercial broadcasting for 22 years I cannot stand by while someone tells someone else not to install a ground wire because it makes their antenna a lightning rod and will cause it to be hit more often. Like it or not but I am fed up with it. The proof is out there. All you have to do is get educated.
:bdh:Pay no attention to Wire Weasel. He has his own way of thinking and although sometimes he can be right, this time he is dead wrong.
Minimum code for a ground wire is 6 gauge. Heavier is better. Minimum for a ground rod is an 8 foot rod driven as deep as you can as close as you can to the antenna. All ground cables should be as short and as direct as possible with no sharp bends and absolutely no loops. The best place to connect the ground wire is right where the antenna mounts to the mast. This ensures a good connection to the antenna itself. Alternately you can just ground the bottom of the mast IF and ONLY IF the antenna mount has a good clean and solid connection to the mast at the top.Ideally you should bond the ground rod wire to the house electrical entrance panel as well but for simplicity you can disconnect the coax cable from the radio gear whenever a storm is coming. This leaves the ground wire as the preferred path for lightning to follow. If the cable was still connected to the radio the lightning can still follow it to the gear even with the ground rod in place. Proper lightning grounding is part science and part an art form but it is not complicated nor is it something that can simply be overlooked. As for not making your antenna system a lightning rod that will attract lightning as Wire Weasel would have you think, tell tht to a guy outside town here. Several years ago a CB'er had his Antron 99 mounted on the eve of his house. No ground rod or wire. the cable came in through the attic and ran behind his cabinets in the kitchen where his radio was located. Lightning hit the antenna blowing it to splinters. it followed the cables down to the kitchen blowing the cabinets off the wall and setting the house on fire. It cause over $30,000 damage to the house. Oh yeah, he had disconnected the coax from the radio thinking that since it was not touching anything metallic it would be safe. Common sense says that if lightning can jump a couple miles of air then a mere fraction of an inch of vinyl insulation on a piece of coax cable means nothing.
Good information there K.K.,
I would also like to add he MAY want to look into a ploy phaser. To the best of my knowledge allot of commerical entities use these and they seem to work ok.
I would also like to add he MAY want to look into a ploy phaser. To the best of my knowledge allot of commerical entities use these and they seem to work ok.
RatsoW8
Supporting Member, W9WDX ARC Member - WD8T
Maybe one of the experts can tell us the difference between how commercial radio stations ground their massive antennas and how to apply that to a home base antenna on a mast in a small back yard. Then describe the correct way to install a lightning rod on your home. Which two will be most alike? I really do want to know the answer.
I'm not an expert but my antennas have never been hit by lightning when everything around me was being hit including the broadcast antenna 1/4 mile away.
I'm not an expert but my antennas have never been hit by lightning when everything around me was being hit including the broadcast antenna 1/4 mile away.
Thank You Ratso ... exactly.
Any comparison between a multi-hundred foot high commercial broadcast setup and very low home CB setup is absurd.
Properly or effectively grounding your antenna system is the safest way to go.
And the safety that is imparted by grounding the antenna system is mostly benefited by minimizing loss to person and property.
Effective grounding of the antenna system helps to minimize the fire hazard that can occur with a lightning strike.
You might lose an antenna or radio still but you have helped to minimize fire that can burn your house down and kill you in the process.
This from a website for Astron Wireless: http://www.astronwireless.com/topic-archives-antenna-lightning-protection.asp
Grounding
The most important lightning protection is a good low impedance Earth/ground connection to the associated equipment. The Earth ground connection should be a copper plated rod preferably at least 5-8 feet in length driven into the ground. This ground rod should be located as close to the equipment as possible, typically just outside of a building at the entry point of the antenna feedlines.
Greater protection can be provided by using additional ground rods spaced at least 8 feet from and connected to the original rod. Substituting plumbing, power ground return and other "so called" grounds for a ground rod is definitely not recommended.
Finally, there should be a large diameter (#4 AWG or larger) copper wire connecting the equipment to the Earth ground. The shorter the wire, the better. Additional information on grounding can be found in Reference 1.
A long time ago it was found by empirical observation that the commercial and broadcast towers and antennas that were guyed and the loose end of the guy cable was left unraveled that these towers and antenna installations suffered fewer strikes and less damage from lighting.
Soon there after this became a common practice to unravel the loose end of the guy cable at the tower or antenna installation.
And soon following that were static dissapator balls that were placed up high on the tower structure.
This from a website called "Tower Protection" : Employing Static Dissipators for Lightning Protection of Antennas Home - Employing Static Dissipators for Lightning Protection of AntennasThere are a wide assortment of lightning air terminals in the form of static dissipators.
Often known as a dissipator, or static dissipation array, this reasonably new and superior air terminal replaces traditional lightning rods in most applications.
It functions as a streamer retarding air terminal.
Static dissipation array generically describes a program making use of point discharge phenomenon to protect towers and antennas and the region around them from a lightning strike.
These function, as the name implies, by dissipating static electrical bill. Between layout aspects, the radius of the dissipator electrode cross-section is important simply because the process which enables dissi*pation of static ground cost to the ambiance is connected to electric field intensity (and flux density) surrounding the lightning dissipator.
Static dissipation arrays supply, in effect, a "lower resistance" route for static ground demand to reach the ambiance, thus preventing a develop up of the soil demand to the value required to trigger a strike on the protected object.
This is why lightning rods have a sharp pointed end.
The afore mentioned devices just take sharp pointed end concept to a higher and more effective level.
The available information on the internet goes on and on but I believe that there is enough evidence to support the notion that grounding versus not grounding shows that it is better and safer to properly gound your antenna/tower/coax system.
And the safety that is imparted by grounding the antenna system is mostly benefited by minimizing loss to person and property.
Effective grounding of the antenna system helps to minimize the fire hazard that can occur with a lightning strike.
You might lose an antenna or radio still but you have helped to minimize fire that can burn your house down and kill you in the process.
This from a website for Astron Wireless: http://www.astronwireless.com/topic-archives-antenna-lightning-protection.asp
Grounding
The most important lightning protection is a good low impedance Earth/ground connection to the associated equipment. The Earth ground connection should be a copper plated rod preferably at least 5-8 feet in length driven into the ground. This ground rod should be located as close to the equipment as possible, typically just outside of a building at the entry point of the antenna feedlines.
Greater protection can be provided by using additional ground rods spaced at least 8 feet from and connected to the original rod. Substituting plumbing, power ground return and other "so called" grounds for a ground rod is definitely not recommended.
Finally, there should be a large diameter (#4 AWG or larger) copper wire connecting the equipment to the Earth ground. The shorter the wire, the better. Additional information on grounding can be found in Reference 1.
A long time ago it was found by empirical observation that the commercial and broadcast towers and antennas that were guyed and the loose end of the guy cable was left unraveled that these towers and antenna installations suffered fewer strikes and less damage from lighting.
Soon there after this became a common practice to unravel the loose end of the guy cable at the tower or antenna installation.
And soon following that were static dissapator balls that were placed up high on the tower structure.
This from a website called "Tower Protection" : Employing Static Dissipators for Lightning Protection of Antennas Home - Employing Static Dissipators for Lightning Protection of AntennasThere are a wide assortment of lightning air terminals in the form of static dissipators.
Often known as a dissipator, or static dissipation array, this reasonably new and superior air terminal replaces traditional lightning rods in most applications.
It functions as a streamer retarding air terminal.
Static dissipation array generically describes a program making use of point discharge phenomenon to protect towers and antennas and the region around them from a lightning strike.
These function, as the name implies, by dissipating static electrical bill. Between layout aspects, the radius of the dissipator electrode cross-section is important simply because the process which enables dissi*pation of static ground cost to the ambiance is connected to electric field intensity (and flux density) surrounding the lightning dissipator.
Static dissipation arrays supply, in effect, a "lower resistance" route for static ground demand to reach the ambiance, thus preventing a develop up of the soil demand to the value required to trigger a strike on the protected object.
This is why lightning rods have a sharp pointed end.
The afore mentioned devices just take sharp pointed end concept to a higher and more effective level.
The available information on the internet goes on and on but I believe that there is enough evidence to support the notion that grounding versus not grounding shows that it is better and safer to properly gound your antenna/tower/coax system.
Not to insert myself into a should you or shouldn't you argument, but I recently went at it with my homeowners insurance company. Turns out they had a few policies in the insurance I couldn't live with, including not allowing me to have my German Shepherd.
While I was being quoted for a new policy, I mentioned that I plan on putting up a tower just to see if there was any other terms I wouldn't like. All of them said they would not cover damages if an installed tower OR antenna was not lighting protected as per local code.
While I was being quoted for a new policy, I mentioned that I plan on putting up a tower just to see if there was any other terms I wouldn't like. All of them said they would not cover damages if an installed tower OR antenna was not lighting protected as per local code.
Ever stop to think that the end result is the same when either site gets hit?
I am in no way suggesting that someone needs to go to the same extent as commercial stations do and some of those commercial sites have done a piss poor job in implementing proper grounding. those are the ones that get knocked off the air frequently.
Perhaps the naysayers can answer me this. A tree is hit by lightning. Why? It does not have a ground wire to "attract" lightning. The person of whom I spoke in the post above did not have any ground in place and his coax was unhooked. Why did lightning hit his antenna and nearly burn the house down? Why does lightning nearly blow a tree apart when it gets hit by lightning but power poles rarely if ever do? Why does lightning strike chimneys? These all do not have ground wires installed except for the power poles and they almost never get damaged.The answer is that the ground wire/rod provides a low impedance path for the energy. Lightning will take whatever path it wants to and it always wants to take the path of least resistance. Provide it with a path of low resistance by installing a ground wire/rod system.
If you study a bit about lightning you will understand how a charge builds up and causes a stepped leader before the strike occurs. this charge can and will build up on anything whether or not it is an insulator or a conductor.
BTW RatsoW8, the reason you have not been hit while the broadcast towers were is because you are not nearly as high as them. I can guarantee you that if/when you take a hit you will suffer much more damage then they have. If they did not have a ground in place they would still get hit because of their height but they would suffer massive damage as the lightning would follow the coax into the transmitter and out to the power looking for a ground. Seen it happen and it was not pretty.
I have taken one confirmed direct hit on a tower many years ago and all that was damaged was a piece of coax where it arced to the tower. A couple years ago I took a hit to the power lines outside the house but the tower was not hit. That one was lucky. i have seen the affects of a poor or non-existent ground too many times to say "don't ground it. you will only attract lightning". Educated people know the truth. Uninformed people spout their version of the truth.
As for using a Polyphaser lightning arrestor, I would recommend the ICE products. They perform better than the polyphaser brand.
What it amounts to is that you can't -prevent- a lightning strike, but you can ~re-direct~ it to some place other than your home/equipment. That means that you provide an 'easier' path to follow rather than into your stuff. It's all about current flowing, and current 'like' the path of least resistance (maybe using 'impedance' rather than 'resistance' would be a better word to use in the case of radio stuff). If it's easier for current to follow a conductor of some kind -into- your 'stuff' rather than to ground/earth, then it's going to take it. Lightning isn't confined to only one path, it can and will take any/all that are available to it. So you provide a 'path of least resistance' to someplace other than your home and what it contains. Lightning is probably the largest current flow you can imagine so what's doing the conducting of that current has to be able to handle that much current for brief periods of time. That means fairly large conductors. And then you have to provide an ending point, that 'someplace to go to', which is most cases means 'dirt'. And that means that more conductive dirt is better than highly non-conductive dirt. (There are ways of measuring how conductive dirt is, but most of us don't have that ability, unfortunately.)
You've probably figured out that while the 'idea' of re-directing lightning is 'simple', the 'doing' of it can be anything but simple. "Why the hell did I ever open that can of 'worms?", right? Protecting your self and equipment isn't all -that- difficult but isn't 'common knowledge', so go find the information you need. The NEC, National Electrical Code, the NFPA, National Fire Protection Agency, are just two places to do that looking and there are more. Most of the larger companies that 'do' lightning protection furnish a lot of information about how to go about it, check'em out.
And there's one last 'catch' to all this, every situation is different and may require different ways of doing that lightning protection. There are no "one size fit's all" thingys for this.
. . . . . .
How do commercial radio stations do all that lightning protection? Very basically they provide a direct path to ground that lightning finds to have very low resistance and that radio wave find to have very high resistance. A very 'selective' short to ground. It still isn't all that simple, but it certainly isn't impossible either.
I'd say 'have fun', but I seriously doubt if that's even possible...
- 'Doc
You've probably figured out that while the 'idea' of re-directing lightning is 'simple', the 'doing' of it can be anything but simple. "Why the hell did I ever open that can of 'worms?", right? Protecting your self and equipment isn't all -that- difficult but isn't 'common knowledge', so go find the information you need. The NEC, National Electrical Code, the NFPA, National Fire Protection Agency, are just two places to do that looking and there are more. Most of the larger companies that 'do' lightning protection furnish a lot of information about how to go about it, check'em out.
And there's one last 'catch' to all this, every situation is different and may require different ways of doing that lightning protection. There are no "one size fit's all" thingys for this.
. . . . . .
How do commercial radio stations do all that lightning protection? Very basically they provide a direct path to ground that lightning finds to have very low resistance and that radio wave find to have very high resistance. A very 'selective' short to ground. It still isn't all that simple, but it certainly isn't impossible either.
I'd say 'have fun', but I seriously doubt if that's even possible...
- 'Doc
RatsoW8
Supporting Member, W9WDX ARC Member - WD8T
I agree in part with what Doc says. I know that lightning is an incredibly power force capable of 10's of thousands of amps and millions of volts. No way any home grounding system is going to dictate where that charge is going to go.
Anyone with any common sense is going to disconnect their coax and toss is out the window when a storm approaches. Better yet, disconnect your equipment, including power supplies, completely from a/c. I even go as far as unplugging modems, tv's, DVD players and everything else I don't want fried if there is a close strike.
Antenna grounding and lightning is ALWAYS a hot topic on every radio forum I belong to. Lightning itself is a very interesting subject.
RatsoW8
Supporting Member, W9WDX ARC Member - WD8T
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