Hi,

Have an attic located, receiving only, random length antenna.

Thinking of stringing one outdoors, but have a few questions, and concerns,
regarding nearby lightning.

a. would you folks agree that having it indoors under the house roof,
probably provides 0.0 % added protection relative to if it was outdoors ?
That any additional indoor protection due to being indoors is probably more
psychological than anything else ?

b. We gets lots of lighning strikes around here. Happy to say that they
have all been "nearby".
This is the crux of what concerns me.

I can't help but feel that if there ever was a truly direct strike on the
wire running (horizontally) outdoors,
a gas discharge tube protector like the Alpha-Delta ones wouldn't really
help much.

But, for the nearby strikes, where possibly just a few hundred volts perhaps
is induced into the wire (but enough to fry the radios front end), would the
Alpha Delta types even trigger ?

c. what's the best protection for "nearby" strikes, other than a total
disconnect ?

BTW: would grounding of the wire be equally effective as a total disconnect
of it ?

Thanks,
Bob

Robert11 wrote:
Hi,

Have an attic located, receiving only, random length antenna.

Thinking of stringing one outdoors, but have a few questions, and concerns,
regarding nearby lightning.

a. would you folks agree that having it indoors under the house roof,
probably provides 0.0 % added protection relative to if it was outdoors ?
That any additional indoor protection due to being indoors is probably more
psychological than anything else ?

b. We gets lots of lighning strikes around here. Happy to say that they
have all been "nearby".
This is the crux of what concerns me.

I can't help but feel that if there ever was a truly direct strike on the
wire running (horizontally) outdoors,
a gas discharge tube protector like the Alpha-Delta ones wouldn't really
help much.

But, for the nearby strikes, where possibly just a few hundred volts perhaps
is induced into the wire (but enough to fry the radios front end), would the
Alpha Delta types even trigger ?

c. what's the best protection for "nearby" strikes, other than a total
disconnect ?

BTW: would grounding of the wire be equally effective as a total disconnect
of it ?

Thanks,
Bob



Having your antenna indoors probably provides a little help against a
direct strike because odds are there'll be flashing or something else
that's metal above it. But I doubt it would be meaningful. I know
someone who had a direct strike at his house and besides the damage
you'd expect, he had a gaping hole in a corner of his basement - the
cement was turned to dust.

Near strikes can still cause a lot of damage.

I use an impedance matching transformer with a couple of ground rods out
by the antenna, and I use fat stranded wire to the ground rods.

The last near strike caused some of the antenna wire to melt, the
ferrite for the transformer vaporized, and bits of the abs plastic
outdoor electrical box it was in were found 15 feet from where it was
mounted.

The coax to the house, and my radio was fine - possibly because I use a
polyphaser between the transformer and the coax too.

On Wed, 14 Dec 2005 11:09:09 -0500, "Robert11"
wrote:

Hi,

Have an attic located, receiving only, random length antenna.

Thinking of stringing one outdoors, but have a few questions, and concerns,
regarding nearby lightning.

a. would you folks agree that having it indoors under the house roof,
probably provides 0.0 % added protection relative to if it was outdoors ?
That any additional indoor protection due to being indoors is probably more
psychological than anything else ?

b. We gets lots of lighning strikes around here. Happy to say that they
have all been "nearby".
This is the crux of what concerns me.

I can't help but feel that if there ever was a truly direct strike on the
wire running (horizontally) outdoors,
a gas discharge tube protector like the Alpha-Delta ones wouldn't really
help much.

But, for the nearby strikes, where possibly just a few hundred volts perhaps
is induced into the wire (but enough to fry the radios front end), would the
Alpha Delta types even trigger ?

c. what's the best protection for "nearby" strikes, other than a total
disconnect ?

BTW: would grounding of the wire be equally effective as a total disconnect
of it ?

Thanks,
Bob


Look at the schematic (scroll down):

http://www.geocities.com/qrp_baluns/QB-9E.html

Note that all points are at DC Ground. Put one of these near the
ground with a nice short fat wire running to a proper ground and
you'll be protected against anything but a direct strike. This
actually is better than a gas discharge tube because it drains of ALL
static electricity, not just that above a certain voltage.

I lived in a VERY high lightning strike area and had two direct hits on my
antennas and several nearby ones.

There is no protection against a direct strike - it's going to blow all
your radio gear and the entire house, even blew my water mains as I had
earthed the antenna with a heavy copper strap to the copper water pipes.

Powerful nearby strikes just "jump" the gas protectors as the spark
generated can be several inches long.

What I learnt through hard experience was:
DON'T
1). have your antennas higher than surrounding rooftops and trees - all you
will be doing is attract the lightning.
2). put a heavy earth strap on your antenna - it just provides a perfect
path for the lightning to ground.

You do have to ground your antenna's to bleed off static and provide a
"radio" earth to your antenna's, but this ground lead should be as thin as
possible, then it doesn't attract the lightning and acts as a fusible link
in the case of a nearby strike.
--
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D GE SRIII
BW XCR 30, Braun T1000, Sangean 818 & 803A.
GE circa 50's radiogram
Antenna's RF Systems DX 1 Pro, Datong AD-270
Kiwa MW Loop
http://www.dxing.info/about/dxers/plimmer.dx

"Robert11" wrote in message
. ..
Hi,

Have an attic located, receiving only, random length antenna.

Thinking of stringing one outdoors, but have a few questions, and
concerns, regarding nearby lightning.

a. would you folks agree that having it indoors under the house roof,
probably provides 0.0 % added protection relative to if it was outdoors ?
That any additional indoor protection due to being indoors is probably
more psychological than anything else ?

b. We gets lots of lighning strikes around here. Happy to say that they
have all been "nearby".
This is the crux of what concerns me.

I can't help but feel that if there ever was a truly direct strike on the
wire running (horizontally) outdoors,
a gas discharge tube protector like the Alpha-Delta ones wouldn't really
help much.

But, for the nearby strikes, where possibly just a few hundred volts
perhaps is induced into the wire (but enough to fry the radios front end),
would the Alpha Delta types even trigger ?

c. what's the best protection for "nearby" strikes, other than a total
disconnect ?

BTW: would grounding of the wire be equally effective as a total
disconnect of it ?

Thanks,
Bob

West By God Virginia is the Lightning "Capital" of U.S.A.It isn't
Florida,Virginia.
cuhulin

Watch your local area so-called "weather" dont know a d..n thing about
the Weather Lieing a..holes on tv,(they have to Lie to keep on gittin
them fed govt grants money) and UNplug your radios accordingly.
cuhulin

Some of the Lienest B.....da and B....es on Earth are them Lieing A..
so-called "weather people" They Dont Know A D..N Thing About The
Weather,,, and they Prove That Everyday.
cuhulin

y'all ever noticed,them wimmins at the so-called weather channel on tv
Radio are always Pregnant? (they sure are Ugly looking too) I used to
subscribe to Robins Nest Pregancy email newsletters from about.com I
used to foward them email newsletters around the World to my wimmins.
cuhulin

Robert 11,

For a Long Wire {Random Wire }Antenna that is located OutSide
you should look at those things that can be done OutSide to
improve your Overall Antenna System from the effects of a nearby
Lightning Strike to your Antenna, Radio Equipment and possibly
your House.

1. Reverse the Lay-Out of your OutSide Random Wire Antenna.
[ Feed the Antenna from the Far-End away from the House. ]

2. Make the Antenna an Inverted "L" Antenna Fed at Ground Level
vice higher up-in-the-Air.

3. Use an OutSide Remotely Located Ground Rod far away from
the House at the base of the Vertical-Up-Leg of the Inverted "L".

4. With a Inverted "L" Antenna use a Matching Transformer (UnUn)
mounted on top of the Ground Rod : Between the Wire Antenna
Element and Ground; and the Coax Cable Feed-in-Line.

5. Use a Coax Cable Feed-in-Line and bury it if possible; directly
under the the horizontal-lay of the Wire Antenna Element.

4. Use an Antenna Switch between the Antenna's and the Radios
in the Shack. The type that lets you disconnect the Antenna from
the Radios and Short the Antenna to Ground for Safety.
Note - Many of these Antenna Switches have GDT's built into them.
http://www.universal-radio.com/catalog/switch/2415.html

5. When you are not using your Radio and Antenna disconnect the
Coax Cable from the Matching Transformer outside the House.


hope this helps - iane ~ RHF

www.lightningstorm.com

Lightning happens everyday and you never know where it might strike
next.
cuhulin