Is an roof vent to plumbing sufficient grounding for a roof antenna?

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#1
I have a vertical, 22' Wilson Ringo style antenna mounted on my roof. The base of the antenna is mounted inside the house plumbing vent. I have been offered several versions of good vrs bad or no grounding when the antenna is mounted inside the metal, house plumbing vent pipe. The SWR is around 1.3 - 1.7; depending on the weather and if the snow connects the gap in the ringo ring.

What is the consensus on using a metal, house plumbing vent to ground a 22' antenna?

Thanks in advance guys.

Les "AKA; SnowWalker"

Pardon the grammar "an" roof vent"
 

DJ11DLN

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#3
No, don't.

It's unsafe from a lighting protection perspective, and questionable from an RF grounding/antenna performance perspective.
It's also very possibly not a strong enough structure. A little wind could do major damage to your house...vent stacks aren't designed to be used as antenna masts, they're just strong enough to hold themselves in place.
 
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#4
"Grounding" can mean a couple of different things.

There is electrical safety ground, like the one on your outlets.

There is RF ground, like for a ground plane/counterpoise

There is lightning ground, to get that energy where it wants to go, more or less safely.

You likely have neither. It's possible that if you did a continuity check between the cast iron drain/waste/vent pipes to your electrical system ground, you might find there is some connection. If there is, it's probably unintentional and shouldn't be relied on.
-I rented half a duplex once in my younger years. The house had zero electrical grounds, just two prong outlets. Some well meaning previous person had installed a GFIC outlet in the bathroom. One day while trying to fix something else (owner was a cheap skate and would knock money off rent if I did repairs), I found that the "electrician" had simply grounded the outlet to the cast iron vent pipe.

As for an RF ground/counterpoise, maybe, but only if it's cast iron/metal/conductive and it is long enough to look like 1/4 wave or longer.

Lightning ground? Well, just about anything will provide that, fences, flag poles, cows, humans with golf clubs, etc. The chances are lightning would find a path. Wouldn't meet any sort of code, though.

I recall you are at some altitude. Considering where you are (Okanagan Valley?) I'm guessing you do get some lightning. I'd do a proper lightning ground on your antenna/coax/station if it was me. While a direct lightning strike is a risk, even nearby ones can cause damage with induced energy.

Static build up from wind, rain, snow, etc. can cause issues. Proper grounding will help with that.

Hobbyists love to talk about how grounds are optional. Phrases like: "I've never been hit by lightning. The coax insulation will protect me. Nobody grounds anything. Some guy on the internet told me I didn't need to. My antenna works fine without it. It'll attract lightning strikes." etcetera, are often used as reasons. None of them are good.

On the flip side, you won't break anything that's been installed correctly if you ground things properly. It may save your radio. It may save your home. It may save your life. Those are good reasons.
 
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#8
The only true ground you can obtain is to attach a #2 stranded copper cable, fed with no bends to an 8 ft copper rod driven in the ground. And for ultimate connection you would need to cad weld the wire to the copper rod and antenna bracket. Now you can get by with mechanical connectors as long as you get them real tight. You cannot trust using any plumbing pipes anymore as alot are violated with some plastic in the middle somewhere and most supply side connections are plastic.
 
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#9
You might want to check out the National Electrical Code section 800 for grounding requirements.
BB
Yes, this.

Safety aside, insurance companies may take a dim view of claim related to a lighting strike, direct or indirect if the antenna is not grounded to at least NEC standards.may

Even an indirect discharge may induce damaging voltage/current levels.
 

phask

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#10
I will begin looking for a grounding system. A four foot, copper claded stake with a 1/4" solid copper wire should do it.
In the US - it's at least 2 rods, bonded together, I think 8'. I'd imagine CA code would be similar.

In the US - ALL rods must be bonded, so if you add oitmust bond to the others.
 
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#11
I will begin looking for a grounding system. A four foot, copper claded stake with a 1/4" solid copper wire should do it.
Yeah, you'll need more than that.

In reality, what you need depends on many factors, and none of us here in internet-land can really tell you what that specifically is without knowing for sure about your specific conditions. I do recall you are up on a hill, so you're probably at a higher risk that most.

Usually knowing soil resistance is required, but that's well outside the hobby realm.
As stated, you'll likely need more than one rod, 8 foot at least, -and- you need to bond all your ground rods together, including the one at your utility (BC Hydro?) connection.

It can get to be a huge undertaking.

It might make more sense to move your antenna. Putting a push up pole or short tower near the existing electric meter might make life a lot easier. That way you have a path straight down from the antenna to a ground rod, and connecting to the utility ground rod is easier.
Industry standard also involves a few other things, if you want to go all the way down this road…
Ground the coax shield at the top of the tower using a manufacturers recommended grounding kit.
Do it again at the bottom of the tower.
Where the coax enters the home, install a Poly-Phaser and ground that to the grounding rods.
Ground your radios to the grounding system also.

It gets expensive, but it would be considered the "right" way to do it at any commercial site. having everything grounded together, including the home electric wiring, you remove any ground potentials between devices.
The resistance in the earth varies, and having separate ground rods not connected can easily cause the potentials to be different, and thus allow energy to flow through the system. Case in point, it's not unheard of for cows near a lightning strike to get killed. Not because they get hit by lightning, but because it's easier for the energy to flow through the cow (in one hoof, out the others) than to go through the earth.
You don't want your antenna/radio on one ground, and your outlets on another.


Of course there are those that will tell you that you don't need to ground things, that it's all "grounded through the power supply". But that's sort of like playing the lottery. Yeah, you -might- win, but you'll more than likely lose.
 
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