[TowerTalk] Re: Coax Disconnection

[Didier Juges]

Shortly after I moved into my current house, lightning hit a tree in my
backyard (it was taller than my then R7 antenna). The house was then about
20 years old and the tree had grown over the in-ground utility cables:
electricity, telephone and cable TV. Anything that was connected to either
of those was fried. Insurance bill: $7,000 (that was about 10 years ago)

The lightning came down the tree and found the bundle of cables in the
ground. When I went to look, there was a 3 feet diameter hole in the ground,
about 2 feet deep and cables big as my wrist cut clean and poking out from
the ground (I have two 400A service installations, so a total of four 400A
cables, which the power company repaired at no charge immediately)

Since the ham gear was all disconnected (as it was after each use, antenna
and AC), that was the only electrical equipment that had no damage in the
entire house :-) At the time, I just ad an HF radio and the R7, so it was
easy to disconnect.

Of course, it is not always practical to disconnect everything. In my
lightning accident, some items that blew are not normally disconnected when
not in use, such as the washer (the dryer survived, amazingly), the range
and garage door opener, all the TVs and VCRs (3 each), stereo, phones,
computer and so on.

Considering that my 50' tower and 15' mast is a much easier target than my
R7 was at the time, I more than ever believe disconnecting is the best
insurance.

Unfortunately, my setup today is considerably more complex, but I have
installed the antenna switches so that it's convenient to unplug the (3)
cables going from the antenna switches to the radios (Beams for HF, 6 and
2m, and the R7 which I still have and use for 40m and the WARC bands, and a
low band dipole). I need to find a way to easily disconnect the rotor cable
(using a multi-pin bayonnet style connector I think), and I am implementing
a wireless setup for the station computer to get rid of the cat 5 cable
going to the router. When the station is not in use, the main AC plug is
unplugged from the wall, so the station is completely isolated from any
outside source.

The 2m FM antenna is in the attic (a J pole), and that's the only one I do
not routinely disconnect.

I live in Florida, the lightning capital of the world :-) so your needs and
mileage may vary.

73,
Didier/KO4BB

----- Original Message ----- 
From: <kb9cry at comcast.net>
To: "Rick Ellison" <rellison at twcny.rr.com>
Cc: <towertalk at contesting.com>
Sent: Thursday, August 07, 2003 11:00 AM
Subject: [allowed] Re: [TowerTalk] Coax Disconnection


> Personally, I have so many cables and wires coming in from outdoors, I
never
> disconnect.  Everyone has lightning protection and my single point ground,
> station ground, perimeter ground, and tower grounds are all very robust
and are
> tied together (CadWelded).  I never disconnect.  Most coax cables do go to
a
> switch so that the desired antenna can be switched to the rig.  I've
received a
> 30 amp surge through the system from a nearby lightning strike and had no
> damage.  (Verified by other means; contact offline for info if curious.)
> Lightning never seems to want to directly strike my antennas; must be the
good
> bleed-off of static from the system.  Commecial radio stations and the
police
> and fire depts. never disconnect and we radio operators shouldn't have to
also
> if we've designed our systems properly, cover all the bases,  and don't
use
> shortcuts.  Phil  KB9CRY
> _______________________________________________
>
> 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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