Where are you located?

>4.a  Water towers (metal) are usually very well bonded.  They make
>good ground interconnects since they are welded.

This is an almost exact case of my problem location. It is on top of a 66' 
water tower that is on a very high elevation for our area. Not the highest 
spot, but close. I have found NO ground what-so-ever on this tank. I asked the 
water dept. about this tank and they said it was not grounded because they did 
not have any equipment on it. They also said it was setting on about 4 ft. of 
sand, soaked in oil to keep the bottom of the tank from rusting. They would not 
let us install an electrical entrance close, so we had to bury conduit with 
ethernet run through it about 100' from the base of the tank to the electrical 
pole where all our equipment is installed.

On the first hit, we had Moto's SS surges installed bonded to the electrical 
ground. Did not help. After our first hit, we grounded all our metal conduit 
that the cat5 runs through from top of the tank to bottom with ground rods at 
the bottom of the tank. Did not help.

We tried "floating grounds," did not help.

Our next step is to get excessive. We are going to ground the tank ourselves, 
connect the tank to the electrical ground to rule out ground loops, install 
Polyphaser surge on all equipment, and ground at top and bottom of the tank on 
all cat5. Do you guys think this will work?


---------- Original Message ----------------------------------
From: Marco Coelho <coelh...@gmail.com>
Reply-To: WISPA General List <wireless@wispa.org>
Date:  Thu, 6 Aug 2009 14:45:05 -0500

>I did a lot of lightning protection for composite aircraft.  After
>initial losses on my towers, here's our basic system:
>1.  All ethernet cables inside or out must be shielded.  Ethernet is a
>high impedance signal that lightning can couple into easily.  We also
>prefer gel filled cables for outdoor work.  "water proof" non-filled
>cables aren't.  Each end of these cable shields must be terminated to
>1.a  Surge protection at entrance to NOC for all CAT5 / Coax.
>Polyphaser rocks for RF.  Again, all of this must go to the ground
>ring with #2 copper.  Between antennas at the top and any RF gear at
>top, polyphaser again.  Keep it out of the radio.
>2.  Ground ring around tower and NOC.  We are in clay, so we have
>about 100 8 ft ground rods interconnected with #2 sold tinned copper
>via cadweld.  Stingers come off these rings for equipment in the NOC,
>and to each leg of the tower.
>3.  Up the tower, 2 #2 stranded conductors. One end tied to the ring
>at the bottom, the other to solid tinned copper ground plates at each
>boom elevation.  Each boom grounded to the plate via cad weld.  Ground
>rod at top of tower grounded to same plate.  Lightning dissapaters
>grounded to same plate.
>4.  Tower legs, booms, and other bolted together structure is not a
>proper ground.
>4.a  Water towers (metal) are usually very well bonded.  They make
>good ground interconnects since they are welded.
>5.  Large whole building surge protection at utility power entrance.
>This must tie to the same ring.
>6.  UPS everything or DC power everything.
>7.  Small prayer when storms come seems to help!
>That said, I've seen a direct strike  hit with so much energy that it
>blew a 1 foot whole through the foundation!
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