From: Garey Barrell 
Subject: Re: [drakelist] CM 12 Solution???



K9SQG{at}aol.com wrote:

> Well, a surge protector (e.g. Alpha-Delta, PolyPhasor, etc.) would
serve a useful function to.  But, good amateur practice suggests
disconnecting the antenna at the rig whenever not in use.  And prior to
storms approaching, disconnecting the antenna leads from the house entry is
a good idea too.  That light bulb, and those surge protectors, will not
defy the laws of physics.  And as to spark gaps that flash over at a few
hundred volts, well, that is a couple of orders or magnitude greater than
what CMOS would like to see...
> 
> Maybe the Hamvention forum on Lightening will enlighten people.
> 
> 73s,
> 
> Evan
> 

The TR-7 (after the first 5,000 or so)  has a gas discharge tube 
across the antenna input.   It "fires" at 90V, which seems kinda 
high, but I guess it protects against low energy, short duration 
spikes from induced lightning or static electrical charges.  The 
Collins 51J-4 has a neon bulb that fires at about 70V for the 
same purpose.

But the series light bulb would do a much better job for 
accidental injection of another transmitter or somesuch.  Shorted 
antenna relays are bad about that!

Nothing is going to do much for a direct lightning strike!  I had 
a friend in VA who had a "really" long wire antenna that extended 
through the trees in his yard.  When storms were in the area, 
he'd disconnect the wire and toss it out the window on the 
ground...  One day his wire took a (?) direct hit.   The 
lightning jumped from the end of the wire (lying on the ground!), 
THROUGH the wall of the BRICK house to a wall outlet INSIDE and 
proceeded throughout the house, destroying just about everything 
electrical in the house!

73, Garey - K4OAH
Atlanta


----------------------------------------------------------------------
Submissions:        drakelist{at}www.zerobeat.net
Subscribe:          majordomo{at}www.zerobeat.net - subscribe drakelist in body
Unsubscribe:        majordomo{at}www.zerobeat.net - unsubscribe drakelist in body
Hopelessly Lost:    majordomo{at}www.zerobeat.net - help in body of message
Brought to you courtesy of TLCHost.net  http://www.tlchost.net/
----------------------------------------------------------------------

---