Roof-mounted antennas and lightening strikes

harshness

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May 5, 2007
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Channel Master makes some great ones.
They offer some protection (up to 6,000V). This is about the same level of protection that you get from a conventional surge protector with coax ports such as this one for not much more green:

Monoprice 12 Outlet Power Surge Protector w/ Coax Protection - 3420 Joules - Monoprice.com

Gotta make sure you read the disclaimer though:
Channel Master Website said:
*This product is designed as a surge suppressor. It is not a lightning rod, does not replace proper grounding, and will not channel lightning to the earth to protect people or structures from injury or fire.
 

harshness

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May 5, 2007
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grounding is such a complex issue that a lot of factors will affect its effectiveness. Moisture in the soil, sand vs clay vs rock, proximity to other ground loads, etc.
These issues are all theoretically settled by additions/refinements to the NEC established by the local jurisdiction. I think I saw one poster here that said they needed more than two rods spaced some distance apart to establish the service ground.
 

comfortably_numb

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Also, always disconnect all outdoor antennas during thunderstorm season.
Once the repack ends in my market (next Friday) I'm planning to use my attic antenna exclusively. It just isn't worth the repeated lightning damage I've received from roof-mounted antennas over the years.

Plus, I'm almost 40 now, and I'm not the spring chicken I once was. I don't mind climbing on rooftops but fear if I fall on my ass, there won't be anybody around to find me.

Now that I've canceled my Dish Network service, I hope to be done with roof climbing permanently.
 

jayn_j

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Yeah, pretty much. But the purpose of a lightning rod is to discharge potential before it gets to arcing stage (lightning) and to provide a low resistance path to ground. The higher resistance of your equipment gets hot and fries if it is the main conduction path.
How Lightning Works

The purpose of lightning rods is often misunderstood. Many people believe that lightning rods "attract" lightning. It is better stated to say that lightning rods provide a low-resistance path to ground that can be used to conduct the enormous electrical currents when lightning strikes occur. If lightning strikes, the system attempts to carry the harmful electrical current away from the structure and safely to ground. The system has the ability to handle the enormous electrical current associated with the strike. If the strike contacts a material that is not a good conductor, the material will suffer massive heat damage. The lightning-rod system is an excellent conductor and thus allows the current to flow to ground without causing any heat damage.
Lightning can "jump around" when it strikes. This "jumping" is associated with the electrical potential of the strike target with respect to the earth's potential. The lightning can strike and then "seek" a path of least resistance by jumping around to nearby objects that provide a better path to ground. If the strike occurs near the lightning-rod system, the system will have a very low-resistance path and can then receive a "jump," diverting the strike current to ground before it can do any more damage.

As you can see, the purpose of the lightning rod is not to attract lightning -- it merely provides a safe option for the lightning strike to choose. This may sound a little picky, but it's not if you consider that the lightning rods only become relevant when a strike occurs or immediately after a strike occurs. Regardless of whether or not a lightning-rod system is present, the strike will still occur
 
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Foxbat

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You could always use a lightning suppression system like NASA employs at their launch facilities.

Oh, wait, that's right, you don't have a billion dollars to protect you $1,000 receiver…
 
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comfortably_numb

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At 70, I have no issues going up on the roof and tinkering or is it tweaking my OTA, FTA and ham antennas!
Not me; I've got all my stuff on the ground or in the attic and I aim to keep it that way :D

My grandfather was in his 80's and still climbing trees. Brave man.
 

navychop

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A friend of mine’s grandfather was up a tree, trimming it with a chain saw. He was in his eighties. He came down, said he wasn’t feeling well, sat at the base of the tree and died.

Maybe we aren’t making ourselves like we used to.


Sent from my iPhone using SatelliteGuys
 

harshness

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May 5, 2007
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Maybe we aren’t making ourselves like we used to.
We're not doing ourselves any favors with diet balance and chemicals to be sure, but the human heart loses capacity to beat like a hummingbird as we grow older. There's a formula for maximum heart rate that is inversely connected to our age: 220 - age.

At some point, the heart is damaged by unusually high activity and this damage is cumulative.
 

Wireless Engineer

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Mar 18, 2019
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ALL antennas MUST as a MINIMUM be grounded according to NEC
code.
There are many myths, hoaxes, and wives tales regarding lightning in the ham radio community as well as the public.
The FACT is lightning CAN and WILL strike anything in order to complete the connection to earth.
Using the largest surface area ground conductor possible directly from the antenna mast to ground is the best protection.
If your ground clamp accepts a maximum of #6 guage solid copper then that is what you use.
Ideally copper strap like what polyphaser sells is the best way to go.
I always run my antenna grounds directly to a 10 foot ground rod via the shortest route without making bends in the conductor.
I then bury a #6 bare copper bonding jumper back to the entrance ground rod in order to satisfy NEC code.
 
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charlesrshell

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ALL antennas MUST as a MINIMUM be grounded according to NEC
code.
There are many myths, hoaxes, and wives tales regarding lightning in the ham radio community as well as the public.
The FACT is lightning CAN and WILL strike anything in order to complete the connection to earth.
Using the largest surface area ground conductor possible directly from the antenna mast to ground is the best protection.
If your ground clamp accepts a maximum of #6 guage solid copper then that is what you use.
Ideally copper strap like what polyphaser sells is the best way to go.
I always run my antenna grounds directly to a 10 foot ground rod via the shortest route without making bends in the conductor.
I then bury a #6 bare copper bonding jumper back to the entrance ground rod in order to satisfy NEC code.
Good info Wireless Engineer. What is the allowable distance for the #6 bare copper bonding jumper from the 10 foot ground rod back to the entrance ground rod in order to satisfy NEC?
 

jorgek

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Mar 11, 2013
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We're not doing ourselves any favors with diet balance and chemicals to be sure, but the human heart loses capacity to beat like a hummingbird as we grow older. There's a formula for maximum heart rate that is inversely connected to our age: 220 - age.

At some point, the heart is damaged by unusually high activity and this damage is cumulative.
I agree as we age we have to adjust. However, the heart is a muscle and needs to be exercised (within reason) to stay heathy.
 

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