Grounding a Lightning Arrestor

[KK7TIF]

Hello all...
Thinks in advance for reviewing my setup here...

I have the 60' Chameleon ECOMM II End Fed Resonant antenna. It's feed point is on a wooden mast attached to the side of the patio roof. It's about 25' up in the air. It runs out to the corner of my yard and is tied off at a height of about 7' using the brick wall, a short piece of 1x2 stuck in there, and then some paracord.

The RG8U cable runs down from UNUN at the top of the mast and transitions into my office/shack through flat window wire and then runs to my equipment.

I want to do some lightning protection at the point it enters the house. I bought the Intellitron LA-1105 Lightning Arrestor to place inline outside my window. The problem is my home's ground is on the other side of the house so I can't bond the lightning ground to it.

My question is this - if it is only used as lightning protection and with the way the LA-1105 works, is there any chance of creating a ground loop with my house? I'm not using it to ground my equipment.

Appreciate your help...
Rob
KK7TIF

 

[WA8ZTZ]

What you don't want to do is to drive a ground rod outside the window and connect the lightning arrestor to that ground rod and call it done.
That way, your radio gear becomes the low impedance interconnecting path between the antenna and the existing building grounding electrode (ground rod).

You must find some way to bond the antenna ground rod to the building ground rod (outside the home) so that in the event of a lightning strike, all parts of the grounding system will be at as near as possible the same potential.
Without seeing your home and landscaping it is impossible for somebody to suggest to you how to best accomplish bonding the two ground rods together. You will have to use your ingenuity to come up with a practical solution to suit your installation.
Basically, you will have to create a perimeter grounding system that connects together the two ground rods with a #6 copper bonding conductor buried in the earth.

The ARRL publication Grounding and Bonding for the Radio Amateur by Silver is an excellent resource.

 

[RRR]

Tie the RG6 in a knot the best you can (obviously not tight, even if you could) as lightning has quite difficulty making it around the loop and into your house. To the nay-sayers, don’t knock it til you try it

 

[prcguy]

Tie the RG6 in a knot the best you can (obviously not tight, even if you could) as lightning has quite difficulty making it around the loop and into your house. To the nay-sayers, don’t knock it til you try it

Lightning can travel many miles to reach your antenna, do you really think a knot in your coax will stop it?

Per NEC, you can add a ground rod where your coax enters the building but you must bond that new ground rod to your main AC entry point with no less than 6ga copper wire. If the run is over a certain length you may have to use larger than 6ga copper.

 

[RRR]

Lightning can travel many miles to reach your antenna, do you really think a knot in your coax will stop it?

In a lot of cases, yes.

Nothing will stop a "direct hit". But I recall a TV installer that did this back in the day, and nobody he did that to ever had lightning enter into their TV.

Lightning surge wants to takes the most direct path to ground. It is very difficult for it to travel around / through a knot.

Again, don't knock it 'til you've tried it. But you don't have to believe me, I am just passing that along for those who may wish to add a little extra protection to their setup.

 

[KC3ECJ]

The basic solution I could think of is to run a ground wire from the arrestor as straight as possible to the house's main ground. Even if some holes have to be drilled.

 

[mmckenna]

In a lot of cases, yes.

Nothing will stop a "direct hit". But I recall a TV installer that did this back in the day, and nobody he did that to ever had lightning enter into their TV.

Lightning surge wants to takes the most direct path to ground. It is very difficult for it to travel around / through a knot.

Again, don't knock it 'til you've tried it. But you don't have to believe me, I am just passing that along for those who may wish to add a little extra protection to their setup.

The loop acts as a kind of choke, but it's not going to protect anything. This is an old amateur radio operator excuse for not doing things the right way.

If this really worked, you'd see big loops of heliax/hard line at big transmitter sites.

If you want to put a big loop of coax before it reaches the protector, that's fine with me, but it's not good advice to use instead of a protector, which is required by NEC.

 

[RRR]

I don't see where anybody stated to do that in place of proper lightning protection, but "in addition to" .

And I don't foresee anybody tying heliax into any type of knot.

 

[mmckenna]

I don't see where anybody stated to do that in place of proper lightning protection, but "in addition to" .

You failed to mention "in addition to" in your original post. That's OK, we were just clarifying it for the new guy.

There's a ton of bad info on lightning protection that gets perpetuated in the hobby realm, especially in ham radio. It's important that those new to the hobby understand the myths versus the electric code, as well as what has been proven to work in the LMR/Cellular industry.

And I don't foresee anybody tying heliax into any type of knot.

Doesn't need to be a knot. There are those that claim that even using a big loop of coax, even heliax, will magically stop lightning in its tracks. I've had people try to convince me that a few wraps of electrical tape are enough to stop lightning, or 3/4" roof sheathing plus a layer of shingles, or not putting in a ground rod so "lightning isn't attracted".

 

[lenk911]

do you really think a knot in your coax will stop it?

Actually in the early 1970's General Electric engineering published a paper on knots in coax and power cords. While some may see this as wacky, it was over 50-years ago and before the invention of the Polyphaser and the development of standards and procedures like Motorola R56. Everyone was looking for ways to minimized lightning damage. GE had a lighting test lab and scientists in Lynchburg to check these theories out.

The theory behind knots is sound. You create a high impedance point in the circuit preceded by a low impedance path to ground. If I recall, lightning has a broad AC component that peaks around 25 MHz. The key is the low impedance path that many forget to install which makes the effort useless and the sight of such, a joke.

By the way, you still see the three knots in the power cord 6 inches apart that comes from that paper. Sign that an old technician has worked on the equipment.

I not saying to use the knots. We are much more knowledgeable and have access to much better products than to resort to 50-year old desperate attempts at mitigating lighting.

 

[trimmerj]

On a similar note, what should be done with rotor control wires? I was just gonna install a couple of XLR Connectors to make a quick disconnect.

 

[Dirtyjim]

I am new to ham and have just installed a 45' metal mast with the associated grounding concerns. My main house grounding is also on the other side of my house. I recently had my electical service upgraded with whole house surge and the new grounding code. At this time it is required in the State of TN, that all ground systems be two 8' ground rods 8 feet apart and tied together with #6 copper. When I decided on my mast position, I called an electical engineer to come out and give me an assessement of the proper way to incorporate my radio gear. He said that you need 10 ohms between your ground rod and any earth withing 16". I ask him about ground loops and he told me that I should not tie my grounds together! I am just adding this info to the mix. I followed the advice of the engineer and my home owner carrier was happy. I am a retired civil engr. and I still am conflicted, At least my house would be covered in the event of a strike.

 

[mmckenna]

On a similar note, what should be done with rotor control wires? I was just gonna install a couple of XLR Connectors to make a quick disconnect.

You need to find the appropriate model that works with the voltage of your rotor:

https://www.polyphaser.com/search?Category=Data+Surge+Protectors&sort=y&view_type=grid