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Lightening arresters

Posted: Sun Sep 29, 2019 1:21 pm
by gscheb
Hello,
Getting close to finishing my setup.
How important are lightening arresters?
Can a computer get fried if it is hooked to the router thru a Ethernet connection?
Is just an old school lightning rod on top of the antenna good enough to protect it?
Thanks confused on this just starting to look into it.

Re: Lightening arresters

Posted: Tue Oct 01, 2019 9:32 am
by swwifty
Very important.

You need to properly ground everything. Proper grounding won't save you from a direct lightening strike (nothing will) but its static electricity build up, and nearby lightening strikes that you need to worry about.

Use shielded ethernet cable to help protect from EMI and static electricity. Then ground it properly to your house ground.

Re: Lightening arresters

Posted: Tue Oct 01, 2019 10:00 am
by gscheb
Sorry,
Confused on this one. Maybe I wasn't clear. I have two antennas on a antenna tower with LMR 400 running into the house and into the Router. Then an Ethernet wire from router to a computer.

If I lost my antennas or my router could deal with it but very concerned about my sons computer getting fried.

Was looking at these lightening arresters that go inline with the lmr 400 cable outside. Do I need to do those? Or just what you are talking about with the shielded Ethernet ground? (which I honestly don't know what that means)

Re: Lightening arresters

Posted: Thu Oct 03, 2019 2:39 pm
by swwifty
gscheb wrote: Tue Oct 01, 2019 10:00 am Sorry,
Confused on this one. Maybe I wasn't clear. I have two antennas on a antenna tower with LMR 400 running into the house and into the Router. Then an Ethernet wire from router to a computer.

If I lost my antennas or my router could deal with it but very concerned about my sons computer getting fried.

Was looking at these lightening arresters that go inline with the lmr 400 cable outside. Do I need to do those? Or just what you are talking about with the shielded Ethernet ground? (which I honestly don't know what that means)
Oh, okay that makes more sense. You only need to use shielded ethernet if you have ethernet running outside (or you are extra paranoid about EMI like me :) )

I would use the gas tube grounding arresters. Mount them outside right before the cable comes into the house, then ground it to your house ground if possible, or an entirely new grounding rod if your house ground is on the other side of the house.

Re: Lightening arresters

Posted: Thu Oct 03, 2019 9:17 pm
by gscheb
Hello again.
I looked into this. And yes says online says use arresters right before you go into the house. But I have 50 foot cables lmr 400 that go from antennas straight to router. So the only connection spot I have to add them is at the antenna connection. At the very top of the run. Is that ok? The ones I seen are online fitting types that.

Re: Lightening arresters

Posted: Fri Oct 04, 2019 7:09 pm
by swwifty
gscheb wrote: Thu Oct 03, 2019 9:17 pm Hello again.
I looked into this. And yes says online says use arresters right before you go into the house. But I have 50 foot cables lmr 400 that go from antennas straight to router. So the only connection spot I have to add them is at the antenna connection. At the very top of the run. Is that ok? The ones I seen are online fitting types that.
I think that should be fine, I don't see why not.

Re: Lightening arresters

Posted: Wed Oct 09, 2019 6:13 am
by gscheb
Hello have another question about grounding. Have a old school tower antenna tower. It is in a concrete footer over 3 feet in the ground. Does this mean that the lightening arresters could be grounded right to the antenna tower? Or do I need to put in a new ground rod for this?

Re: Lightening arresters

Posted: Wed Oct 09, 2019 10:49 am
by swwifty
gscheb wrote: Wed Oct 09, 2019 6:13 am Hello have another question about grounding. Have a old school tower antenna tower. It is in a concrete footer over 3 feet in the ground. Does this mean that the lightening arresters could be grounded right to the antenna tower? Or do I need to put in a new ground rod for this?
Is the tower itself grounded to any rods right next to it? If so, I'd use that. If you have nothing, then I'd ground it right next to the tower, but the tower itself should be bonded/grounded as well.

Re: Lightening arresters

Posted: Wed Oct 09, 2019 11:07 am
by gscheb
Hello,
No the tower itself is not grounded to a ground rod.
The tower is in the ground though. Think you are saying that isn't enough?
Think you are telling me to put in a ground rod and ground the antenna tower to that ground rod?
Then once that is done can ground the lightening arresters right to the antenna tower then?

Re: Lightening arresters

Posted: Thu Oct 10, 2019 8:17 am
by swwifty
gscheb wrote: Wed Oct 09, 2019 11:07 am Hello,
No the tower itself is not grounded to a ground rod.
The tower is in the ground though. Think you are saying that isn't enough?
Think you are telling me to put in a ground rod and ground the antenna tower to that ground rod?
Then once that is done can ground the lightening arresters right to the antenna tower then?
I'm not super familiar with tower grounding techniques, but I've always seen towers grounded. if its in the ground, I would think that would be sufficient. I would still ground the lightening arresters directly to a ground, as you want the least path of resistance to ground.

Take all of this with a grain of salt, as i'm not an expert in grounding at all.