There is no way to cure that potential lightening hit. Maybe an "air
terminal" on top of the tower. Jury is still out on that.
However, without knowing the particulars of the switching, is there an
"automatic" way of doing the switching by using transmission line stubs to
accomplish the same thing as the relay?
If not, replace the relays and cross your fingers. How long was the antenna
up before the hit? Assume that to be the MTBF, and if that is acceptable,
consider it a part of the maintenance of the antenna.. If not, try a
different antenna without active components up in the air that you can not
get at to fix easily. That is precisely my situation and why I don't do
relays up in the air.
----- Original Message -----
From: "Dave Anderson, K4SV" <email@example.com>
Sent: Wednesday, August 24, 2005 8:29 PM
Subject: [TowerTalk] Yagi lightning protection
> Hi All,
> I wonder if any of you have this problem and how you
> solved it.
> I have a Force12 EF240/230 a 2 element 40 and 2
> elements on 30 meters on the top of my tower. Due to
> the narrow bandwidth I am using a relay box provided
> by F12 that allows switching between the CW end of the
> band or SSB end by adding or removing additional
> inductance. When the relay is de-energized it is in
> the CW band.
> I had a direct lightning hit on the tower, no damage
> in the shack due to massive grounding but it appears
> the relay contacts on the 40/30 yagi has been welded
> closed. I can energize the coil and it draws 160 mA
> like normal but no physical movement of the armature.
> To be sure I will check when a bucket truck becomes
> So here's my question, Is there a way to protect the
> relay from damage when lightning hits? I suspect
> lightning hit one side of the element and the other
> side of the element arced to the boom which is
> grounded. The relay contacts were in the middle.
> Any ideas?
> Dave K4SV...
> Yahoo! Mail
> Stay connected, organized, and protected. Take the tour:
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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