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Re: [TowerTalk] Copper strap bonding ideas?

Subject: Re: [TowerTalk] Copper strap bonding ideas?
From: K8RI <>
Date: Thu, 12 Jan 2012 17:31:14 -0500
List-post: <">>
On 1/11/2012 2:42 PM, Rik van Riel wrote:
> On 01/11/2012 09:33 AM, Jim Miller wrote:
>> lightning induced power surge don't warrant the use of strap. It also
>> sounds like augmenting the bonding from panel to ufer is not time well
>> spent.
>> Is the above correct?
> Indeed.  The way to protect your house, is to ensure that everything
> in your house is at the same potential.
> Normally this is easy, since stuff only comes into the house in one
> spot, and every ground is bonded together at that spot.
With most homes around here that is impossible.  Power, telephone and 
cable come in the front, but  the way the homes are laid out, virtually 
all antennas have to come in the back or ends.  I rerouted the satellite 
cable  so there are two common entrances which are  then tied together.  
The ground systems for my towers are tied together and run to the 
service entrances. Yes that is plural. That is because the shop and 
house have separate electrical feeds and meters and the one for the shop 
is under a heavy concrete slab/approach so it had to be reached 
"through" the shop. At least they are fed from the same transformer.

For the house with all the *stuff* coming in from the front neither the 
cable nor the phone line were grounded. It appeared that at one time the 
phone line had one of the old spark gaps next to the panel.  I added 
grounding for each of those and tied them into the house electrical 
ground.   Unfortunately for the antennas that was not possible.  They 
all come in at the back.  There are currently 3 LMR-600s, control cables 
for the 6-pack and remote antenna switches, and two RG-6 from the 
satellite dish...I think I'm forgetting something...Oh! there are three 
runs of CAT-6 running between the den and shop which pretty much 
parallel the coax runs to the tower and about 6 to 10 feet to the East.  
The grounding bulkhead at the house has the shortest possible connection 
to the house electrical ground which happens to be where the ground ties 
into the electrical panel, but that's a good 30 feet distant.

The joining of the electrical grounds is because the antennas mounted at 
the shop and main tower are all accessible from either station which are 
also grounded together.  IE I have one large ground system that is for 
all of the antennas, masts, and towers fed by two separate stations.

The main tower has taken 17 visually verified hits since it went up with 
no damage to any equipment.  I was thinking that an early hit took out a 
new computer and one 2-meter rig but that was when I had the old tower 
with the repeater antenna on it and the ground system was not finished.

This is primarily flat land with a few glacier moraines thrown in so any 
tower that extends above the trees is a prime target for lightning.

The new tower is about 30 feet North of the old one and 10 feet taller. shows both towers as 
I was just finishing up the 45G and not taken down the old one.  The 
repeater antenna is gone.  There is a quadature array of UHF TV antennas 
on the 45G at this point.  I just wanted to try them out.   It was only 
up for a couple of weeks and was replaced by  a cross boom holding 
arrays of two 12L on 144 and two 11L on 440.Unfortunately at that time 
the UHF TV band was so wide I could not get the spacing where i could 
get rind of the extra lobes, but it worked good out to about 125 miles.  
The tribander and TV antennas on the old tower had separate rotators.
>> My antenna and controls all come into the house adjacent to the service
>> entrance and terminate on a copper panel which will be bonded to the same
>> ufer. The length from this "antenna panel" to the ufer is about 10ft (floor
>> to celiing distance). What would you recommend as the bonding wire for this
>> length?
> Nothing wrong using copper strap to bind the copper panel
> to your service entrance ground.  Using a large diameter
> ground wire would be fine too.
In mine I use a bare #2 which is a bit of over kill as the service panel 
ground is #6 with 3 skinny ground rods installed at the insistence of 
the electrical inspector..
> Use whatever you prefer, as long as there is a really
> good connection, you should be fine.
> The point of this connection is to ensure that both your
> coax and your house wiring will be at the same potential
> when there is a nearby strike, so lightning induced
> current will not take a detour through your favourite
> electronic toys...
Mine has worked well ... so far.  The next one could be one of those 
super strikes that takes out half the stuff in the house.
There is no 100% guarantee that will protect you from nature, but all 
this work does put the odds in your favor.


Roger (K8RI)


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