Outside antenna with battery powered scanner

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fredg

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So I have been researching ground options for my outside antenna, I have learned the correct way to ground the antenna and to bond it to my main house ground rod (once I find it).

My question is if I use a battery powered scanner will that make much difference in the overall safety of the system? It seems to me that if I eliminate AC voltage from the system it will be much safer all around.

What do you guys think?
 

K5MPH

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If you talking about grounding a 2 prong plug will not give you proper ground any way......
 

fredg

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If you talking about grounding a 2 prong plug will not give you proper ground any way......
Not sure what you are referring to.... I was talking about grounding my antenna.
 

fredg

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Using batteries to power your scanner will eliminate one source of damage caused by over voltage from the AC power line caused by a nearby lightning strike.
BB
Yeah I guess the answer was kind of obvious :) I tend to ask obvious answer questions at times.

With my plugged in desktop scanner it stays on all the time, however I have a baby monitor "repeater" hooked up to it so I use a handheld set to the baby monitor frequency when I want to listen while walking around the house or close by outside.

If I use batteries and a handheld I will just have to turn it on and off when I want to listen.

I'm thinking I would only use the handheld attached to the outside antenna during the active weather months, like we are in now, then at other times I would use the desktop.

Just kicking around different ideas.
 

prcguy

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One thing that bonding your antenna ground rod to the main house ground is eliminating a difference of potential between the two grounds. I once had an antenna mast grounded at the opposite end of the house from the main breaker panel and I measured about 90v between the coax on that antenna to the ground connection in my house outlets. If I had a radio plugged in with a three prong plug and disconnected the antenna while touching the radio I would get a shock.

I believe it may have been caused by my antenna ground rod being closer to the neighbors breaker panel than mine and the neighbors panel may have been fed from a different leg of the local grid and their ground rod was at a different potential than mine but my antenna mast ground was closer to the neighbors and was closer to their ground potential. Just a theory but it hurt when changing antennas. A scanner running from a battery would suffer the same problem if you where holding on to the scanner and touched something else grounded in your house.

The fix of course was bonding my antenna ground rod to my house ground and that fixed the problem and most rules of the NEC are for electrical safety like I mentioned above rather than surviving a direct lightning hit.
prcguy
 

fredg

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One thing that bonding your antenna ground rod to the main house ground is eliminating a difference of potential between the two grounds. I once had an antenna mast grounded at the opposite end of the house from the main breaker panel and I measured about 90v between the coax on that antenna to the ground connection in my house outlets. If I had a radio plugged in with a three prong plug and disconnected the antenna while touching the radio I would get a shock.

I believe it may have been caused by my antenna ground rod being closer to the neighbors breaker panel than mine and the neighbors panel may have been fed from a different leg of the local grid and their ground rod was at a different potential than mine but my antenna mast ground was closer to the neighbors and was closer to their ground potential. Just a theory but it hurt when changing antennas. A scanner running from a battery would suffer the same problem if you where holding on to the scanner and touched something else grounded in your house.

The fix of course was bonding my antenna ground rod to my house ground and that fixed the problem and most rules of the NEC are for electrical safety like I mentioned above rather than surviving a direct lightning hit.
prcguy
Excellent info thanks! My issue right now is I can't find the main breaker ground rod for my house. My house is really old, the main house is over 100 years old and the addition is probably 40 years or more old. There is no ground wire coming off my electric meter which is odd. The meter and main power lines to the pole were replace a couple of years ago by the electric company so I would think they would have noticed the lack of a ground wire then.

My house sits in 6 lots with the closest neighbor some distance away so I don't think I will have the issue you experienced.

Not to mention none of the wall outlets in my house are grounded, they have 3 prong plugs but no grounds (bad I know). I use surge strips with 15 amp breakers and will be installing GFCI outlets soon as adding proper ground wires is not possible (mainly due to finances).
 

digitalanalog

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never grounded an antenna in over 30 years of hobby and never got hit, must be my luck.
really don't see ANY need, Just my 2 cents

But better safe then sorry......... for some.
 

n5ims

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My question is if I use a battery powered scanner will that make much difference in the overall safety of the system? It seems to me that if I eliminate AC voltage from the system it will be much safer all around.

What do you guys think?
Using a battery operated radio with an outside antenna will only be a little bit (well, a micro bit at best) safer than an AC powered radio with an outside antenna. First off, if you get hit by a direct lightning strike the lightning may flow down your antenna wire into your house and jump into whatever it can find to dissipate to ground.

Yes, grounding the antenna and using lightning protection on your coax is important (very important in fact), but you can't count on it to be 100% effective. Let's say that it works quite well and 95% of the million amps flows directly to your ground. The remaining 50,000 amps can still do quite a bit of damage. Don't think that simply disconnecting the antenna during a lightning storm will save you either (although it's probably still a good idea). The lightning just jumped several miles through nothing but moist air, a few feet more once inside your house won't faze it much.

We had an indirect strike several years ago (it didn't hit the house, but did hit a neighbor's tree) that caused a fair amount of damage to electronics in the house. There was no external antenna at the time so that wasn't a factor. One thing I did notice which I wasn't expecting was the strike managed to spot weld the washer to the dryer (apparently part of the strike came down the dryer and jumped to the washer to flow through to the water pipes). Remember that this was an indirect strike so the damage was just from a large amount of electricity flowing through the air into my home's electric, phone, and cable-tv lines that were all properly grounded and buried between the house and their connection to the utility companies lines.
 
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