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[TowerTalk] Lightning Protection Components

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Subject: [TowerTalk] Lightning Protection Components
From: (DAN)
Date: Thu, 10 Apr 1997 18:42:29 -0700
Charles H. Harpole wrote:
> Please, do not operate radio when lightning is within hearing distance (if
> you hear thunder, shut off radio and leave the area)
> Here is the best advice on lightning, regardless of what engineers or
> other eggspurts tell you:
> When you can hear thunder, unplug all radios and all accessories from AC
> (best on one central big plug), and unplug all coax and all other wires
> that come from ants and rotors and all else--including ground wires!
> Then, you have all your radios etc sitting completely isolated there on
> your operating bench.  Lightning might still get them via jumping to them
> due to them being metal objects, but much less likely.
> Then, you do not put your body near where the antennas terminate (maybe in
> window sill?) and watch the light show from somewhere else IN the house.
> ABSOLUTELY NOTHING else is as effective.  Do not bother with arresters,
> pill plugs devices, or whatever.  Just unhook it all! This is very cheap,
> BTW.
>  And, when all the tower talk guys jump on this advice herein, ask them :
> "If my radio is sitting by itself --unplugged from all outside sources--
> on a table via what path does lightning get to it?"
>  All other lightning
> "protection"
> methods are not as good.  Leave hooked up only what must be so, i.e.,
> repeaters and TV xmitters.  de K4VUD
> --
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This advice contains some good information, and some dangerous information.

Completely disconnecting your radio from all power, antenna, and ground 
connections is a 
good approach to protecting the radio.

The advice to "don't bother with lightning arrestors" is in error, however.  
Here is a 
brief explantion of one aspect to consider.  If your antenna is hit, and your 
coax is 
disconnected in your shack (laying on the desk for example), the potential 
across the 
connector can be hundreds of thousands of volts.  The resulting arc can (and 
often does) 
set fire to adjacent materials.  (This happened to member of our local club 
year--his closet caught fire.  Fortunately, he was home to put the fire out.)  
A good 
ground ground system and a lightning arrestor serve to divert the current and 
to keep 
the potential low enough to reduce the possibility of fire & other damage in 
your home.

The experts who engineer these protection systems aren't fools.  When they make 
recommendation, they have a good reason for it.  Be sure to learn those reasons 
you choose to ignore the recommendations.

I'm an electrical engineer, and have been a ham for 38 years.  I have a good 
system and I disconnect my equipment when I think a storm is coming.  This way, 
both my 
equipment and my home are reasonably well protected.

Be careful & 73,
Dan - W4TQ

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