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Old December 14th 05, 07:27 PM posted to rec.radio.shortwave
w_tom
 
Posts: n/a
Default Gas Discharge Lightning Protector Units ?

Single point earth ground is THE most critical component of
a lightning protection 'system'. Yes it is a system - not
just one silly component called a protector. If that
protector does not discuss the 'system', then the protector is
suspect.

Do you think for one minute that the radio chassis ground is
sufficient for protection? The you did not even learn
principles taught in primary school concerning Ben Franklin.

Does a protector stop, block, or absorb the transient? Only
in your dreams. Effective protectors perform same as Franklin
demonstrated in 1752. You don't stop, block, or absorb what
three miles of sky could not. And yet that is the snake oil
that some protector manufacturers sell to those in denial of
their primary school science lessons.

Protector is nothing more than a temporary connection from
that lightning struck antenna to earth ground. Sometimes that
connection can be made with a wire. But if a direct hardwire
connection cannot be made (ie to AC electric or telephone),
then we use a protector to do the same thing.

Furthermore distance to earth is critical. The connection
through protector must be less than 10 feet. That means the
antenna lead must first drop to earth so that a protector can
make the less than 10 foot connection to earth ground.

Also water pipes have long been unacceptable grounding. The
only wire connected to water pipes is a wire that removes
electricity from those pipes. This being post 1990 code.
Furthermore, grounding to water pipes would be more than 10
feet to earth ground - totally unacceptable.

In the other post is a concept essential to lightning
protection - the single point earth ground. It is
demonstrated by this industry professional where each
structure - the building and the tower - have their own single
point earth grounds:

http://www.erico.com/public/library/...es/tncr002.pdf

From
http://lists.contesting.com/_towerta...il/004413.html
The basic scenario is to install a Single Point Ground
System that is installed at the building entry. It shunts
everything to ground before it goes in the building. If
you can keep it outside, then you don't really have to do
much inside. IMO disconnecting the cables is more
psychological than preventive.


Yes, early 20th Century hams would disconnect the antenna,
put that antenna lead inside a mason jar, and still suffer
damage. Again the idea that one would stop or block the
direct lightning strike was proven wrong - as demonstrated by
others who even suffered explosive damage as a result. Once
that antenna lead was earthed, then lightning damage stopped.
Success because they shunted (connected, diverted) lightning
to earth (what it seeks) rather than silly mythical solutions
that try to stop or absorb a transient. The most critical
component in a lightning protection system is not the
protector. The protection 'system' is only as effective as
its most critical component - single point earth ground.

Robert11 wrote:
Thinking of getting (finally) one of the gas discharge tube lighning
"protectors: for my receiving only long wire antenna.

Radio is grounded (hopefully) via a solid strap to the water pipes and also
via the ac power center-pin
grounding pin.

a. They seem to come in two flavors. One with an extra lug for running
another ground wire, and those that don't; the argument being, I guess, that
the metal case connects to the chassis
(e.g., via a short piece of coax), and thus shunts any voltage transients
that way.

Any opinions on whether the lug with a separate ground wire is a good idea
and really needed ?

b. Alpha Delta units still pretty much the state of the art, or... ?

c. They usually quote a number like 60 V for the gas discharge tripping.
Wouldn't this usually be more than enough to fry the front end ?

Thanks,
bob