Bill Turner wrote:
If I don't ever hear it again, that will be ok by me. :-)

Consider that there might be two ways that you would never
hear it again and one is NOT OK. :-)
--
73, Cecil http://www.qsl.net/w5dxp

On Fri, 16 Dec 2005 22:55:09 GMT, Owen Duffy wrote:


Very often, the target of effective lighting protection of radio
installations is minimisation of voltage drops or potential
differences internal to an installation as a result of lightning
discharge current rather than trying to minimise the voltage to
"ground" resulting from the current.

I should have expanded that to say:

Minimisation of potential differences is often obtained by one or more
of:
- providing an alternate low impedance path to ground so that less
current flows through the equipment room;
- single point earthing to reduce the voltage drop in earthing
conductors internal to the equipment room;
- equipotential bonding to reduce the voltage drop between the
equipment room earth and other parts of the building, and other
services or structures (eg water, gas, telephone, power).

There may be standards or codes that apply to lighting protection in
your area, they are worth checking, and while they may not mandate
lighting protection, they may mandate the way in which it is done if
it is done. That may have implications for your insurance.

Effective lightning protection is a very expensive business, and if
you don't need "continuous operation" and have a simple configuration,
it is much cheaper and effective to ensure that feedlines and similar
conductors (like rotator cables) are totally disconnected from the
shack at times of high risk.

Owen
--

But, as a more or less theoretical question, to minimize the
possibility of
lightning hitting the antenna at all, or inducing large voltages in it,
is
it better to just leave the now "floating" antenna alone, or is it
better to
ground one end of it ?

Why ?......................................

I prefer to ground all the feedlines. I have a ground strip outside
my window with a bunch of SO-239's. I just screw em all in when
bad wx is around. I doubt it will make much difference as to the
likelyhood of being struck. Horizontal wire antennas are not struck
that often compared to verticals, trees, etc.
But if it is, I'd prefer it to be grounded to reduce flashing, etc.
My metal mast takes the brunt of the strikes to ground. All
my grounding of the feedline does is take any left over energy
on the coax to ground. Same for induced energy from near
strikes. And it can be a good bit, as I actually can hear my
connectors arc with nearby strikes. Never leave antenna wires,
or feedline ends in the house, or in bottles, etc..You want it
out of the house if it's not protected. Even if using a grounded
switch, etc, I'd prefer not to have it running through the house.
IE: ground wire leading along the wall, etc to the switch to
ground it. Most switches ground the unused connectors, or
have a ground position. I don't like those in the house if the
feed is unprotected by gas tubes, etc...
MK

"Robert11" wrote
is it better to just leave the now "floating" antenna alone,
or is it better to ground one end of it ?
______________

Most MW broadcast stations use series-fed, insulated towers that usually are
(by far) the highest structures in the area. These stations operate
successfully in lightning storms using a combination of means. First is an
arc gap connected across the tower feedpoint to a very low resistance earth
ground (120 1/4-wave, buried radials). The gap is set to flash over at some
margin above the peak voltage present during normal operation. They also
use a "static drain choke" to earth ground, which is a high Z at the MW
frequency, but doesn't let high static potentials develop on the tower. The
last part of the protection system is supplied by transmitter circuitry that
senses instantaneous phase changes in transmission line current, and kills
r-f output for some milliseconds so as not to sustain any arc that occurs in
the antenna system.

Maybe some of these techniques could be useful in amateur radio
installations.

RF

"Robert11" wrote
is it better to just leave the now "floating" antenna alone,
or is it better to ground one end of it ?
______________

In anticipation of a thunder storm just leave it floating. Not that it
will prevent a direct lightning strike but it MIGHT prevent damage to
equipment and, more important, to yourself.

But it is advisable not to attempt to disconnect it using bare fingers
during the progress of a thunder storm. I am a little superstitious
so I use the XYL's rubber kitchen gloves.

There's only one thing you can be absolutely certain of - lightning
exactly obeys the Mathematical Laws of Probability.

See the works of Sir Ronald Arthur Fisher, the greatest statistician
of all time. Beautifully explained in plain English. He dabbled mainly
in Genetics, Agriculture, the Weather, and the mathematics thereof.
But I'm not aware of anything specifically he had to say about the
statistics of lightning strikes. You will have to work things out for
yourself. In all probability nothing seriously will happen to YOU. So
don't worry about it.

Just DON'T fly kites using 1/2-wavelength metal wires during thunder
storms. Not even on the 10m band. Or shelter from the rain under
solitary trees. It's asking for trouble but you probably won't get
any.

As for me, I'm 80 years of age, and I'm still alive. I've never won
the national lottery. But perhaps that can be explained by the fact
that I've never entered it.

I hope the foregoing has helped to set your mind at rest.
----
Reg, G4FGQ
==========================================

Reg Edwards wrote:
. . .
See the works of Sir Ronald Arthur Fisher, the greatest statistician
of all time. Beautifully explained in plain English. He dabbled mainly
in Genetics, Agriculture, the Weather, and the mathematics thereof.
But I'm not aware of anything specifically he had to say about the
statistics of lightning strikes. You will have to work things out for
yourself. In all probability nothing seriously will happen to YOU. So
don't worry about it.
. . .
As for me, I'm 80 years of age, and I'm still alive. I've never won
the national lottery. But perhaps that can be explained by the fact
that I've never entered it.

I hope the foregoing has helped to set your mind at rest.

I'd be willing to wager that there are places in Florida which have more
lightning strikes in a single summer than have occurred at your QTH (or
mine) in the past 80 years.

Roy Lewallen, W7EL

"Roy Lewallen" wrote
I'd be willing to wager that there are places in Florida which have
more
lightning strikes in a single summer than have occurred at your QTH
(or
mine) in the past 80 years.

=======================================
Roy, your's is a safe bet.

Nevertheless, statistically speaking, the good people of Florida
should be more scared of dying from gunshot wounds. But it doesn't
seem to worry them very much.
----
Reg.

Reg Edwards wrote:
Nevertheless, statistically speaking, the good people of Florida
should be more scared of dying from gunshot wounds. But it doesn't
seem to worry them very much.

Now that so many Floridians are packing, it's the criminals who
should be worried.
--
73, Cecil http://www.qsl.net/w5dxp

"Reg Edwards" wrote
In anticipation of a thunder storm just leave it floating. Not that it
will prevent a direct lightning strike but it MIGHT prevent damage to
equipment and, more important, to yourself.
.... etc etc removed by major clippage
I hope the foregoing has helped to set your mind at rest.
__________

Possibly you thought this relevant to the original post. But then why not
thread it so, rather than to mine?

RF