Hi,
I want to install a vertical, fed with an SGC230 at the bottom, but
concerned about minimising chance of a lightning strike on a bare
conductor.

Would it give more protection / solve the problem, if I encased it
in a fibreglass yacht mast which I happen to have ?

I plan it to be approx 40' high with the top 25' being a fibreglass
yacht mast with the wire running up the inside. Top would be
insulated / sealed so no ions could spray out, attracting a strike
.... am I going the right way ?

Thanks,
Nick

I want to install a vertical, fed with an SGC230 at the bottom, but
concerned about minimising chance of a lightning strike on a bare
conductor.

Hi Nick,
There is virtually nothing you can do to prevent a strike hitting your
antenna. But you can attempt to pursuade Mother Nature to send the damaging
electrons somewhere where they won't do damage. Get a Polyphaser or ICE or
other good lightning arrestor made for this purpose and install it with a good
ground under the antenna. Your objective is to divert the strike around your
equipment and into the ground, taking the path that YOU provide for, not the
one that the lightning strike would otherwise select. Your ground must have
the capacity to absorb the electrons which arrive in massive quantities in a
few microseconds, otherwise they will give up on you and find their own path
to ground, often not the way you would prefer.
There is good information on this technique on the polyphaser website,
probably www.polyphaser.com. Most likely you will get about 50 more replies
so be prepared, this is one of the favorite and most often discussed topics on
this newsgroup.

Rick K2XT

Rick wrote:
I want to install a vertical, fed with an SGC230 at the bottom, but
concerned about minimising chance of a lightning strike on a bare
conductor.

Hi Nick,
There is virtually nothing you can do to prevent a strike hitting your
antenna. But you can attempt to pursuade Mother Nature to send the damaging
electrons somewhere where they won't do damage. Get a Polyphaser or ICE or
other good lightning arrestor made for this purpose and install it with a good
ground under the antenna. Your objective is to divert the strike around your
equipment and into the ground, taking the path that YOU provide for, not the
one that the lightning strike would otherwise select. Your ground must have
the capacity to absorb the electrons which arrive in massive quantities in a
few microseconds, otherwise they will give up on you and find their own path
to ground, often not the way you would prefer.
There is good information on this technique on the polyphaser website,
probably www.polyphaser.com. Most likely you will get about 50 more replies
so be prepared, this is one of the favorite and most often discussed topics on
this newsgroup.

Rick K2XT



-----------


I agree with Rick.

Additionally, don't forget that your homeowner's insurance policy will
usually reimburse you for damage incurred via lightning strikes. But be
sure to see it in writing. Personal assurances from your agent are not
enough. Have the agent show it in the writing of YOUR policy, or one
identical to the one that you will be purchasing.

The last thing that you need after the damage is done is for the
insurance company to try to wiggle out of covering your lightning
damaged equipment.

Ed, NM2K

On Mon, 12 Nov 2007 10:55:25 -0500, Ed Cregger
wrote:

The last thing that you need after the damage is done is for the
insurance company to try to wiggle out of covering your lightning
damaged equipment.

The first question they will investigate:
"Does your grounding meet code?"

73's
Richard Clark, KB7QHC

Rick wrote:
I want to install a vertical, fed with an SGC230 at the bottom, but
concerned about minimising chance of a lightning strike on a bare
conductor.

Hi Nick,
There is virtually nothing you can do to prevent a strike hitting your
antenna. But you can attempt to pursuade Mother Nature to send the damaging
electrons somewhere where they won't do damage. Get a Polyphaser or ICE or
other good lightning arrestor made for this purpose and install it with a good
ground under the antenna. Your objective is to divert the strike around your
equipment and into the ground, taking the path that YOU provide for, not the
one that the lightning strike would otherwise select. Your ground must have
the capacity to absorb the electrons which arrive in massive quantities in a
few microseconds, otherwise they will give up on you and find their own path
to ground, often not the way you would prefer.
There is good information on this technique on the polyphaser website,
probably www.polyphaser.com. Most likely you will get about 50 more replies
so be prepared, this is one of the favorite and most often discussed topics on
this newsgroup.

Rick K2XT



-----------


I agree with Rick.

Additionally, don't forget that your homeowner's insurance policy will
usually reimburse you for damage incurred via lightning strikes. But be
sure to see it in writing. Personal assurances from your agent are not
enough. Have the agent show it in the writing of YOUR policy, or one
identical to the one that you will be purchasing.

The last thing that you need after the damage is done is for the
insurance company to try to wiggle out of covering your lightning
damaged equipment.

Ed, NM2K

"Rick" wrote in message
...

I want to install a vertical, fed with an SGC230 at the bottom, but
concerned about minimising chance of a lightning strike on a bare
conductor.

Hi Nick,
There is virtually nothing you can do to prevent a strike hitting your
antenna.

Interesting topic!

I have a tall metal pole supporting one end of a long wire HF antenna. This
tall metal pole is set in 1 cu yard of concrete. Is this concrete suitable
for conduction into mother earth or should I run a large copper strap from
the pole to an earth rod?

JERD
VK5JE

Is this concrete suitable for conduction into mother earth or should I run
a large copper strap from the pole to an earth rod?

Hi Jerd,
The latter, and you should have more than one if possible. The strap should
not have bends in it, should be low inductance (a copper strap is better
than a wire, etc.). Remember there are zillions of electrons coming down
that pole, and they all have to get into the earth, and all the ones in
front are being pushed by the ones in back, all screaming "Hurry up, or get
the hell outta the way, cause I gotta go...... real bad." And if they don't
get outta the way, the ones in back will jump around them like a New York
driver in a traffic jamb, to find a faster way to get where they are headed.
And you don't want that to happen because the other path may be through your
coax and into your house/equipment.
Now how does that portray the situation? That's the best I can do !

Rick K2XT

Rick a écrit :
Is this concrete suitable for conduction into mother earth or should I run
a large copper strap from the pole to an earth rod?

Hi Jerd,
The latter, and you should have more than one if possible. The strap should
not have bends in it, should be low inductance (a copper strap is better
than a wire, etc.). Remember there are zillions of electrons coming down
that pole, and they all have to get into the earth, and all the ones in
front are being pushed by the ones in back, all screaming "Hurry up, or get
the hell outta the way, cause I gotta go...... real bad." And if they don't
get outta the way, the ones in back will jump around them like a New York
driver in a traffic jamb, to find a faster way to get where they are headed.
And you don't want that to happen because the other path may be through your
coax and into your house/equipment.



Now how does that portray the situation? That's the best I can do !

Awesome

--
Ker2x

On Nov 12, 12:46 pm, "JERD" wrote:
"Rick" wrote in message

...



I want to install a vertical, fed with an SGC230 at the bottom, but
concerned about minimising chance of a lightning strike on a bare
conductor.

Hi Nick,
There is virtually nothing you can do to prevent a strike hitting your
antenna.

Interesting topic!

I have a tall metal pole supporting one end of a long wire HF antenna. This
tall metal pole is set in 1 cu yard of concrete. Is this concrete suitable
for conduction into mother earth or should I run a large copper strap from
the pole to an earth rod?

JERD
VK5JE

Should be fairly good as is. Acts as sort of a "UFER" ground.
http://search.yahoo.com/search?p=ufe...p=mss&ei=UTF-8
I don't think adding another wire to ground would hurt anything,
but it's probably not needed to act as a decent lightning ground.
My mast is sitting directly into the earth. But I also run about
3 wires from the base of the mast to the ground system under
the mast, which is connected to all other grounds.
I've had two direct strikes that I know of, and they were non events.
The mast seemed to be fairly low resistance as the strikes were
very quiet. Or at least, thats one personal method I use to tell
if an object is a good lightning ground. A poor ground like a tree
will give a very loud crack as it strikes, and I'm not talking about
the sonic boom which occurs a very short time later. I'm
talking about the actual direct sound you hear from the strike,
which also gives a "click" to the auditory nerve if you are close
enough.
MK

"Nick" wrote in message
...
Hi,
I want to install a vertical, fed with an SGC230 at the bottom, but
concerned about minimising chance of a lightning strike on a bare
conductor.

Would it give more protection / solve the problem, if I encased it in a
fibreglass yacht mast which I happen to have ?

I plan it to be approx 40' high with the top 25' being a fibreglass yacht
mast with the wire running up the inside. Top would be insulated / sealed
so no ions could spray out, attracting a strike ... am I going the right
way ?

Thanks,
Nick
Nick

With the voltages involved in a lightning strike, the fibreglass mast will
not make much, if any, difference. Rain fall and dirt deposits will create a
conductive path along the mast a few days or weeks after it has been
erected. Lightning is attracted to the highest pointiest thing in an area,
no matter what substance it is made from. Churches and trees are made of
insulating materials and they attract more strikes than anything else on
land. It was common to have to regularly rebuild the towers and steeples of
medieval churches before lightning conductors were installed. The average
steeple usually lasting no more than a century before suffering catastrophic
damage from a lightning strike. At the time, this was just accepted as a
sign that the parishioners were insufficiently pious, or had transgressed in
some way.

The fibreglass mast is ideal as a support and to provide weather protection
for your antenna element(s), but do not count on it reducing the chances of
a lightning strike it it is the tallest structure within 400 yards or so.
Various tables and maps are available on the internet showing the frequency
of lightning strikes per year per square mile or square kilometer for most
areas in earth. These should help you evaluate the risks in your particular
area. Forty feet is not particularly high and if you live in an area with
less than 20 lightning days per year, I would evaluate the risk of a strike
as being low. There is always a statistical risk and that's a chance you
have to accept when dealing with any force of nature.

Try to ensure that there is a good earth connection at the base of the
vertical antenna using earth rods and/or buried radial wires so that in
event of a strike, the lightning energy is dissipated into the ground rather
than transmitted along the feedines into your house. A switch to disconnect
and earth the antennas when equipment is not in use is always a good idea. A
look through the MFJ catalogue will give you an idea of what equipment is
available.

Mike G0ULI