Earlier this year I buried a lot of Heliax and rotator wires in a 250 foot
long trench going from my tower base to the house. The wires were not
connected at either end and were not touching the tower and shortly after
burying them my tower was struck by lightning. I saw burn marks on the ends
of the buried wires and on the Heliax connectors so voltage can definitely
be induced into nearby conductors. As Jim said the best place for the
protector is at the entry panel to the shack. I wonder if it does any harm
to also have them at the tower base?
John KK9A
To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Lightning Protection Question
From: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Sat, 11 Sep 2010 08:53:25 -0700
I disagree (and agree with K1TTT) -- lightning protection devices are
protecting you radios by short the voltage on the center conductor to
the shield. They cannot do that at the tower -- voltage can be induced
on the coax between the tower and the shack, and a protector at the
tower is too far away to offer much protection at RF. The best place for
them is at the entry panel to the shack.
The SHIELDS of coax SHOULD be bonded at top and bottom of the tower.
73, Jim K9YC
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