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[TowerTalk] Where to put Lightning Arresters

To: <towertalk@contesting.com>
Subject: [TowerTalk] Where to put Lightning Arresters
From: "Jim Thomson" <jim.thom@telus.net>
Date: Fri, 10 Nov 2017 09:27:54 -0800
List-post: <mailto:towertalk@contesting.com>
Date: Fri, 10 Nov 2017 08:35:45 -0600
From: "Jeff" <keepwalking188@ac0c.com>
To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] Where to put Lightning Arresters

<I put the arrestors at the coax feed points into my shack at the home run 
<panel location.  And also out at the tower base on the termination of each 
antenna stack feeder.  The reason for that is I want to buy some insurance 
in the case of my tower mounted switching and that expensive in-ground coax 
run back to the shack.

The shields of the coax on the tower are bonded and hit the tower's ground 
system but the center of each coax is left floating.  My thinking is that I 
prefer that suppressor take a hit and try to dump some of that HV on the 
center of the coax to the tower ground as best it can there instead of 
lighting up the tower switching and the coax back to the shack.  Suppressors 
are expensive but compared to the other stuff relatively easy to replace in 
the event they die the lightning inspired death out at the tower.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

##  I pout one at SPG just inside basement... and a  2nd one at base of tower, 
abt 4 ft above the
ground.   The one at the tower serves several functions.  It acts as an 
interface and demarcation point,
between flexible coax   going up the side of the crank up, and the bigger coax 
going back to shack. 
It also grounds the shields of both the smaller  flexible coax and the larger 
coax.... to the base of the tower,
and tower grounding setup..with its  3 x rods, and cadwelds etc.   Bare, 
stranded 2 gauge copper is  run
from tower ground setup, back to SPG  setup in basement... since they are only  
65 ft apart.  The bare, stranded
2 gauge copper is buried into the ground.. and run along side the house.   
Electrical contractor and ham buddy
insisted on the  run of 2 gauge between the spg and tower base.   I believe its 
in our electrical code. 

##  Having a demarcation point means I can isolate the larger and smaller  
coax.    So either a double female or
lightning arrestor will do the job.    Coax braid also bonded to CM mast... via 
a remote switch box..at top of tower. 
Both ants use helical hairpins at their feedpoints.    Then the center 
conductor and braid are  zero ohms between em...
via the hb hairpins..which are made from silver plated  .25 inch OD  copper 
tubing.  So in both cases, the center conductor
is zero ohms to top of tower anyway. 

## But Im not taking any chances with expensive coax, etc.  So in goes the pair 
of lightning arrestors. 
german HoffI  brand, 10 kw rated, into a 3:1  swr, and 7-16 dins on both sides. 
  Field replaceable
gas tubes. 

Jim   VE7RF       

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