dealing with sparks on atenna cable end

[spillthewine]

Whenever a storm comes around, I unplug my scanner antenna and place the end in a mason jar. I am noticing sparkplug-like sparking inside the jar. At the same time my nearby computer monitors black out for a couple of seconds, I've also had some nearby electronic equipment failures. Seems there is electric in the air around my room. This is before the storm arrives, not lightning but from static electric in the outside air.

I have a 12' antenna mounted on the roof of my house. I've read tons of opinions on lightning and grounds. I'd prefer not to run a ground from the antenna to a dedicated ground rod out of fear of burning down my house by attracting more lightning.

What I'm thinking of doing is shunting the end of the antenna cable when in the mason jar, that is, connecting the two sparking leads together so it all stays up on the antenna. My fear is that will burn my antenna. I could also relocate my antenna lead and jar somewhere else in the room, and maybe seal the top of the jar.

thanks...

 

[n5ims]

You most likely have it wrong. A good, well designed and installed ground system on your antenna will help bleed off the charges and may help prevent lightning from hitting your antenna. Lightning strikes when enough of a charge has built up enough to trigger the strike. By bleeding the building charge to ground that strike may never happen.

The lack of a proper grounding system could also keep your insurance company from paying for the damage from that lightning strike. They will quite often deny a claim when no grounding of an antenna mast is present since you failed to attempt to mitigate any damages. This grounding should be up to code so you don't give them any reason to deny your claim.

Shorting the connections won't really do anything in a lightning strike situation. It may even allow for more current to flow since it can easily flow down both the center lead and the shield. Lightning will be happy to jump from that coax, through the mason jar into any nearby cable (your electric lines, phone lines, cable TV lines, etc.) and cause damage along the way. When there is simply static charges, you may allow enough to build up in your cable to damage the dielectric and ruin the coax or any coils in your antenna.

 

[jwt873]

Whenever a storm comes around, I unplug my scanner antenna and place the end in a mason jar. I am noticing sparkplug-like sparking inside the jar.

That's actually pretty common... As storm clouds pass overhead, charges are built up on the active antenna elements. (There doesn't have to be any active lighting happening).

The coax acts as a big capacitor. Once the charge builds up to a certain point, it overcomes the resistance of the air and arcs between the center and the ground.

One simple way to stop the sparking is to short the connector. Get the proper socket for your connector and just solder a wire across the ground and center conductor.

It doesn't hurt to ground the shorted plug as well. That way all the static will bleed off. It won't attract lighting. But As N5IMS points out.. It won't help with a direct lighting hit either. Actually, not much will help with a direct strike.

 

[KC4RAF]

Don't ground the antenna system?

Your house/home. Your fault when lightning strikes and possibly damage your place.
and as 873 posted about static in the air and what to do.

 

[mmckenna]

Whenever a storm comes around, I unplug my scanner antenna and place the end in a mason jar. I am noticing sparkplug-like sparking inside the jar. At the same time my nearby computer monitors black out for a couple of seconds, I've also had some nearby electronic equipment failures. Seems there is electric in the air around my room. This is before the storm arrives, not lightning but from static electric in the outside air.

Classic static electricity. You need to provide a way of draining off that energy. It can be caused by wind, snow, etc, so only unplugging your radio when you see the storm coming isn't going to save your radio.

I have a 12' antenna mounted on the roof of my house. I've read tons of opinions on lightning and grounds. I'd prefer not to run a ground from the antenna to a dedicated ground rod out of fear of burning down my house by attracting more lightning.

Flawed argument. Lightning travels thousands of feet through the air. A few more feet of air between your antenna and anything that is already grounded in your home, like your entire electrical system, isn't going to help you in the least. By having a piece of metal sticking up in the air you've already created the issue. Now you need to deal with it, not ignore it.

What I'm thinking of doing is shunting the end of the antenna cable when in the mason jar, that is, connecting the two sparking leads together so it all stays up on the antenna. My fear is that will burn my antenna. I could also relocate my antenna lead and jar somewhere else in the room, and maybe seal the top of the jar.

thanks...

Again, not going to help. That energy is looking for a path to ground. If you don't provide one, it'll make one. Again, a few feet of air inside your house isn't going to save you. A mason jar certainly won't stop it, either. A glass jar might increase comfort with the static electricity and prevent it from accidentally being touched, or touching something metal, but that's it. It's not going to do a dang thing for lightning.

You'd probably be a bit safer by throwing the entire coax cable outside when this is happening.

Ideally you need to ground your antenna support. Ground your coax outer shield and install a PolyPhaser type protector on your coax before it enters the house.

 

[spillthewine]

Thanks for all the informative replies, Gentlemen. I have decided to run a 6g copper ground from the antenna into an immediately located ground rod. Then I will bond that rod to my mains rod on the other side of the house. Good points made by all here, glad I asked.

 

[K2RNI]

I had that happen too, I freshly installed some new coax through the wall and it was windy that night and I hard a loud clicking type sound. I look over to see static sparks jumping between the center conductor and outer shielding. Managed to capture a pic of it.

http://i.imgur.com/ioo56Qe.jpg