If you want to read a short paper on Lighting Protection and learn; obtain a
GE paper on "Living with Lighting" by Kenneth Guthrie. After Ken retired
from GE, he taught a course at George Washington University on Lighting
Protection. Ken has passed away some years ago but his works still remain an
authority on lighting.
Transmission lines should be grounded at four major points:
1. At the top of the tower
2. Just above the bend where the line leaves the tower
3. At the entrance to the equipment building (A Polyphasor or similar
device here will help discharge any high voltage on the center conductor of
the transmission line)
4. At the equipment end of the line
The grounds on the tower are short and always directed down to be connected
to the tower.
The grounds at the entrance to the equipment building ant at the equipment
will depend on the type of system grounding the building owner has put in
place. EG: Halo Ground Ring, Copper strap to bond all cabinets together,
Simple common ground wire routed at the bottom of the equipment for all
users to connect to, NO GROUND SYSTEM AT ALL! Every installation will be
slightly different.
Always put a lighting protector on the AC Power Lines. There are some good
ones and some cheap ones. You get what you pay for. Spend the money and buy
a good one and connect it to the building/system ground.
If your equipment does not have a SOLA CV transformer in it as does GE MASTR
II and some Motorola's buy a SOLA CV transformer to add to the lighting
protection on the AC side.
My success rate over 45 years is 99.999% by following these guidelines. The
one failure had a direct hit on the antenna and a second direct hit on the
AC pole transformer, both shot to he--. However the radio equipment and the
transmission line were not damaged.
Kenny's last bit of advice was always "Spend all that you can afford for
lighting protection and then borrow some more".
Fred
W5VAY
----- Original Message -----
From: "Joe" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Sunday, January 16, 2005 4:49 AM
Subject: Re: [Repeater-Builder] LDF5-50a
>
> We use 3 ground kits at work (cell company). The
> first at the top of the tower, the second at the base
> of the tower just before it makes the turn to go
> horizontal, and the third outside the entry port to
> the building. All ground kits are installed with the
> groundkit pigtail pointing towards the ground so that
> any possible lightning hit will have the shortest path
> to gound with the fewest turns in the groundwire.
> Inside the building, we install a polyphasor to the
> feedline and gound it to the common ground ring inside
> the shelter. We take very few damaging hits from
> lightning at the hundreds of sites we have.
> Interestly, most lightning damage comes in the power
> lines.
>
> Keep all groundwires as short as feasibly possible and
> always flowing downhill. I learned this from a
> lightning protection device installer. Never expect
> lightning to flow uphill, it always wants to go down
> and seek ground.
>
> 73, Joe, K1ike
>
> --- Eric Lemmon <[EMAIL PROTECTED]> wrote:
> > Rick,
> >
> > The conventional practice is to install a grounding
> > kit at the point just before the feedline enters the
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
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