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Old April 17th 05, 12:19 AM
§ Dr. Artaud §
 
Posts: n/a
Default Antenna Suggestions and Lightning Protection

Every year, I fear the spring and summer. I have a random wire antenna
that traverses one side of my property, the wire extending about 70 feet.
No lightning protection. I remove the wire from the radio when I am at home
and I know that I storm is coming. But when I am at work, and storms happen
unexpectedly, the radio stays connected. Even protecting the radio from the
static of a nearby lightning strike by disconnecting it doesn't protect the
house from the results of a strike to the wire.

I would like to switch to a V shaped antenna, perhaps it is what they refer
to as an "inverted V" extending from a central point on my house to both
sides of the property. I would like to feed the antenna with coax, so as to
reduce the likelihood of household interference. The feed would only be
about 20 feet long. I would have trouble grounding it at the apex of the V,
since that would be on the house itself and the patio is directly below it,
providing much cement but little ground to place the rod. Though I could
drill the patio, I am unsure of the pipes below it.

My lot, at least as far as the usable area for the antenna is concerned,
would be about 30 feet wide and 70 feet long, with the elevation of the V
to be approximately 12 feet from the ground.

Can anybody conceptualize an antenna that I can use, with lightning
protection, and provide links to it? Is anybody using something similar?

Thanks for any help.

Dr. Artaud
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Old April 17th 05, 12:25 AM
dxAce
 
Posts: n/a
Default



"§ Dr. Artaud §" wrote:

Every year, I fear the spring and summer. I have a random wire antenna
that traverses one side of my property, the wire extending about 70 feet.
No lightning protection. I remove the wire from the radio when I am at home
and I know that I storm is coming. But when I am at work, and storms happen
unexpectedly, the radio stays connected. Even protecting the radio from the
static of a nearby lightning strike by disconnecting it doesn't protect the
house from the results of a strike to the wire.

I would like to switch to a V shaped antenna, perhaps it is what they refer
to as an "inverted V" extending from a central point on my house to both
sides of the property. I would like to feed the antenna with coax, so as to
reduce the likelihood of household interference. The feed would only be
about 20 feet long. I would have trouble grounding it at the apex of the V,
since that would be on the house itself and the patio is directly below it,
providing much cement but little ground to place the rod. Though I could
drill the patio, I am unsure of the pipes below it.

My lot, at least as far as the usable area for the antenna is concerned,
would be about 30 feet wide and 70 feet long, with the elevation of the V
to be approximately 12 feet from the ground.

Can anybody conceptualize an antenna that I can use, with lightning
protection, and provide links to it? Is anybody using something similar?


An inverted 'V' itself would be vertical... a horizontal 'V' I think is what you
envision.

Lightning protection is itself a science I suppose. Never had a direct hit here,
but did see blue sparklers off a disconnected lead 20 or so years ago.

dxAce
Michigan
USA

Drake R7, R8, R8A and R8B

http://www.iserv.net/~n8kdv/dxpage.htm




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Old April 17th 05, 03:09 AM
 
Posts: n/a
Default

Lightning strikes very often happen on very pretty Summertime
days/nights when you least expect lightning to happen.There are very
good ways to protect your radio antennas and radios agains't lightning
strikes.I don't know much of those ways,perhaps someone who does know
will show up and elaborate about such things.I know this much though,
www.brickwall.com www.pricewheeler.com I own an use a Brickwall
model 8R15.
cuhulin

  #4   Report Post  
Old April 17th 05, 12:33 PM
Jack Painter
 
Posts: n/a
Default


"§ Dr. Artaud §" wrote
Every year, I fear the spring and summer. I have a random wire antenna
that traverses one side of my property, the wire extending about 70 feet.
No lightning protection. I remove the wire from the radio when I am at

home
and I know that I storm is coming. But when I am at work, and storms

happen
unexpectedly, the radio stays connected. Even protecting the radio from

the
static of a nearby lightning strike by disconnecting it doesn't protect

the
house from the results of a strike to the wire.

I would like to switch to a V shaped antenna, perhaps it is what they

refer
to as an "inverted V" extending from a central point on my house to both
sides of the property. I would like to feed the antenna with coax, so as

to
reduce the likelihood of household interference. The feed would only be
about 20 feet long. I would have trouble grounding it at the apex of the

V,
since that would be on the house itself and the patio is directly below

it,
providing much cement but little ground to place the rod. Though I could
drill the patio, I am unsure of the pipes below it.

My lot, at least as far as the usable area for the antenna is concerned,
would be about 30 feet wide and 70 feet long, with the elevation of the V
to be approximately 12 feet from the ground.

Can anybody conceptualize an antenna that I can use, with lightning
protection, and provide links to it? Is anybody using something similar?

Thanks for any help.

Dr. Artaud


The Inverted-vee is a center (or off-center) fed dipole with it's ends lower
than the feedpoint. Rarely a desired design, it usually results from being
unable to elevate both ends equal to the feedpoint of a half wave dipole. It
nonetheless works fairly well and is a "complete" antenna, requiring no
grounding. It is not a vertical antenna as Ace suggested.

However, for lightning protection, all antenna feedlines regardless of
antenna type should be shield-grounded if using a coax feedline. The first
point of this shield-grounding should be as near as possible to where a
grounding conductor/jumper/bond can be first located. That means on the
tower if the tower is the feedpoint of the inverted-vee, or where the
feedline first reaches earth-grade at 90 degrees from the feedpoint. Coax is
again shield-grounded at the ground rod used as the shack's single point
ground. A surge protector or oft-called lightning arrestor is then used to
protect the equipment where the feedline originates.

If it is physically possible for the antenna to take a direct lightning
strike (not a probability if nearby objects are higher) then the feedpoint
shield ground is the primary discharge point, and should have a network of
ground rods connected by heavy (#4 or larger copper wire or wide copper
straps). Even if a direct strike is not possible, indirect strikes
(flashovers from a nearby tree or other higher object) are still possible,
and the first shield ground remains of primary importance in the protection
scheme. Feedline running along the earth or even buried a few inches in the
earth are also subject to magnetic and capacitive coupling of lightning
strikes nearby. The near surface of earth carries 10's of thousands of volt
potential from strikes as far as 100 yards away. Any ground system that is
connected to equipment in the shack has the potential to reference these
voltages right onto the grounded equipment cases in the shack. This is why
proper bonding of inside equipment and all grounding systems is vital to
prevent this ground potential rise from exiting the equipment through AC
power connections out the rear of the equipment. See my site for further
information about bonding and grounding antennas and equipment:

http://members.cox.net/pc-usa/station/ground0.htm

Best regards,

Jack Painter
Virginia Beach, Virginia


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Old April 17th 05, 12:43 PM
dxAce
 
Posts: n/a
Default



Jack Painter wrote:

"§ Dr. Artaud §" wrote
Every year, I fear the spring and summer. I have a random wire antenna
that traverses one side of my property, the wire extending about 70 feet.
No lightning protection. I remove the wire from the radio when I am at

home
and I know that I storm is coming. But when I am at work, and storms

happen
unexpectedly, the radio stays connected. Even protecting the radio from

the
static of a nearby lightning strike by disconnecting it doesn't protect

the
house from the results of a strike to the wire.

I would like to switch to a V shaped antenna, perhaps it is what they

refer
to as an "inverted V" extending from a central point on my house to both
sides of the property. I would like to feed the antenna with coax, so as

to
reduce the likelihood of household interference. The feed would only be
about 20 feet long. I would have trouble grounding it at the apex of the

V,
since that would be on the house itself and the patio is directly below

it,
providing much cement but little ground to place the rod. Though I could
drill the patio, I am unsure of the pipes below it.

My lot, at least as far as the usable area for the antenna is concerned,
would be about 30 feet wide and 70 feet long, with the elevation of the V
to be approximately 12 feet from the ground.

Can anybody conceptualize an antenna that I can use, with lightning
protection, and provide links to it? Is anybody using something similar?

Thanks for any help.

Dr. Artaud


The Inverted-vee is a center (or off-center) fed dipole with it's ends lower
than the feedpoint. Rarely a desired design, it usually results from being
unable to elevate both ends equal to the feedpoint of a half wave dipole. It
nonetheless works fairly well and is a "complete" antenna, requiring no
grounding. It is not a vertical antenna as Ace suggested.


They are generally vertically oriented, therefore the 'inverted vee'
designation.

dxAce
Michigan
USA



However, for lightning protection, all antenna feedlines regardless of
antenna type should be shield-grounded if using a coax feedline. The first
point of this shield-grounding should be as near as possible to where a
grounding conductor/jumper/bond can be first located. That means on the
tower if the tower is the feedpoint of the inverted-vee, or where the
feedline first reaches earth-grade at 90 degrees from the feedpoint. Coax is
again shield-grounded at the ground rod used as the shack's single point
ground. A surge protector or oft-called lightning arrestor is then used to
protect the equipment where the feedline originates.

If it is physically possible for the antenna to take a direct lightning
strike (not a probability if nearby objects are higher) then the feedpoint
shield ground is the primary discharge point, and should have a network of
ground rods connected by heavy (#4 or larger copper wire or wide copper
straps). Even if a direct strike is not possible, indirect strikes
(flashovers from a nearby tree or other higher object) are still possible,
and the first shield ground remains of primary importance in the protection
scheme. Feedline running along the earth or even buried a few inches in the
earth are also subject to magnetic and capacitive coupling of lightning
strikes nearby. The near surface of earth carries 10's of thousands of volt
potential from strikes as far as 100 yards away. Any ground system that is
connected to equipment in the shack has the potential to reference these
voltages right onto the grounded equipment cases in the shack. This is why
proper bonding of inside equipment and all grounding systems is vital to
prevent this ground potential rise from exiting the equipment through AC
power connections out the rear of the equipment. See my site for further
information about bonding and grounding antennas and equipment:

http://members.cox.net/pc-usa/station/ground0.htm

Best regards,

Jack Painter
Virginia Beach, Virginia




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Old April 17th 05, 02:16 PM
David
 
Posts: n/a
Default

On Sun, 17 Apr 2005 07:43:50 -0400, dxAce
wrote:


The Inverted-vee is a center (or off-center) fed dipole with it's ends lower
than the feedpoint. Rarely a desired design, it usually results from being
unable to elevate both ends equal to the feedpoint of a half wave dipole. It
nonetheless works fairly well and is a "complete" antenna, requiring no
grounding. It is not a vertical antenna as Ace suggested.


They are generally vertically oriented, therefore the 'inverted vee'
designation.

dxAce
Michigan
USA

''Efficiency is less than a horizontal dipole of similar height, but
the radiation pattern is more omni-directional which may be considered
to be an advantage.''

http://www.smeter.net/antennas/inv_vee.php

I think characterising the Inverted V as an ''inferior'' choice is
wrong.


  #7   Report Post  
Old April 17th 05, 02:24 PM
dxAce
 
Posts: n/a
Default



David wrote:

On Sun, 17 Apr 2005 07:43:50 -0400, dxAce
wrote:

The Inverted-vee is a center (or off-center) fed dipole with it's ends lower
than the feedpoint. Rarely a desired design, it usually results from being
unable to elevate both ends equal to the feedpoint of a half wave dipole. It
nonetheless works fairly well and is a "complete" antenna, requiring no
grounding. It is not a vertical antenna as Ace suggested.


They are generally vertically oriented, therefore the 'inverted vee'
designation.

dxAce
Michigan
USA

''Efficiency is less than a horizontal dipole of similar height, but
the radiation pattern is more omni-directional which may be considered
to be an advantage.''

http://www.smeter.net/antennas/inv_vee.php

I think characterising the Inverted V as an ''inferior'' choice is
wrong.


Damn, you finally got something right.

dxAce
Michigan
USA


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Old April 17th 05, 02:26 PM
Jack Painter
 
Posts: n/a
Default


"dxAce" wrote

Jack Painter wrote:

"§ Dr. Artaud §" wrote
I would like to switch to a V shaped antenna, perhaps it is what they

refer
to as an "inverted V" extending from a central point on my house to

both
sides of the property. I would like to feed the antenna with coax, so

as
to
reduce the likelihood of household interference.


Thanks for any help.

Dr. Artaud


The Inverted-vee is a center (or off-center) fed dipole with it's ends

lower
than the feedpoint. Rarely a desired design, it usually results from

being
unable to elevate both ends equal to the feedpoint of a half wave

dipole. It
nonetheless works fairly well and is a "complete" antenna, requiring no
grounding. It is not a vertical antenna as Ace suggested.


They are generally vertically oriented, therefore the 'inverted vee'
designation.

dxAce
Michigan
USA


Huh? Please describe what you mean by a "horizontal inverted-vee" v.s. a
"vertical oriented inverted-vee" Dr. Arnaud clearly described an
inverted-vee where the house forms the center feedpoint and the ends are
lower at opposite ends of his property. This is like every other
inverted-vee I ever heard of, whether center point was a tower or any other
kind of support. Just because the ends slope downward (giving some vertical
component to the antenna) does not make it a vertical-oriented antenna. It
is not. It does have less directionality because of it's vertical component,
and slightly wider bandwidth than a pure horizontal half wave dipole. It is
also less efficient.

Best regards,

Jack Painter
Virginia Beach, Virginia


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Old April 17th 05, 02:38 PM
dxAce
 
Posts: n/a
Default



Jack Painter wrote:

"dxAce" wrote

Jack Painter wrote:

"§ Dr. Artaud §" wrote
I would like to switch to a V shaped antenna, perhaps it is what they
refer
to as an "inverted V" extending from a central point on my house to

both
sides of the property. I would like to feed the antenna with coax, so

as
to
reduce the likelihood of household interference.


Thanks for any help.

Dr. Artaud

The Inverted-vee is a center (or off-center) fed dipole with it's ends

lower
than the feedpoint. Rarely a desired design, it usually results from

being
unable to elevate both ends equal to the feedpoint of a half wave

dipole. It
nonetheless works fairly well and is a "complete" antenna, requiring no
grounding. It is not a vertical antenna as Ace suggested.


They are generally vertically oriented, therefore the 'inverted vee'
designation.

dxAce
Michigan
USA


Huh? Please describe what you mean by a "horizontal inverted-vee" v.s. a
"vertical oriented inverted-vee" Dr. Arnaud clearly described an
inverted-vee where the house forms the center feedpoint and the ends are
lower at opposite ends of his property. This is like every other
inverted-vee I ever heard of, whether center point was a tower or any other
kind of support. Just because the ends slope downward (giving some vertical
component to the antenna) does not make it a vertical-oriented antenna. It
is not. It does have less directionality because of it's vertical component,
and slightly wider bandwidth than a pure horizontal half wave dipole.


No, actually it has less bandwidth. Look it up!

It is
also less efficient.


You get back to me after you go to 'antenna school'! And, after you finally
figure out the difference between 'horizontal' and 'vertical'.

I don't think I ever really mentioned a 'horizontal inverted vee'...

You really need to pick up an antenna book or two and actually go out and build
some stuff.

Please, go back and read the original posters comments and actually try to
envision what he was proposing, which would seem to be a 'horizontal vee'.

At any rate, using an 'inverted vee', or a 'horizontal vee' dipole antenna for
general shortwave listening is simply a bad idea.

Your inexperience is certainly showing this morning, Jack.

dxAce
Michigan
USA


  #10   Report Post  
Old April 17th 05, 02:50 PM
Jack Painter
 
Posts: n/a
Default


"dxAce" wrote

Jack Painter wrote:

"dxAce" wrote

Jack Painter wrote:

"§ Dr. Artaud §" wrote
I would like to switch to a V shaped antenna, perhaps it is what

they
refer
to as an "inverted V" extending from a central point on my house

to
both
sides of the property. I would like to feed the antenna with coax,

so
as
to
reduce the likelihood of household interference.


Thanks for any help.

Dr. Artaud

The Inverted-vee is a center (or off-center) fed dipole with it's

ends
lower
than the feedpoint. Rarely a desired design, it usually results from

being
unable to elevate both ends equal to the feedpoint of a half wave

dipole. It
nonetheless works fairly well and is a "complete" antenna, requiring

no
grounding. It is not a vertical antenna as Ace suggested.

They are generally vertically oriented, therefore the 'inverted vee'
designation.

dxAce
Michigan
USA


Huh? Please describe what you mean by a "horizontal inverted-vee" v.s.

a
"vertical oriented inverted-vee" Dr. Arnaud clearly described an
inverted-vee where the house forms the center feedpoint and the ends are
lower at opposite ends of his property. This is like every other
inverted-vee I ever heard of, whether center point was a tower or any

other
kind of support. Just because the ends slope downward (giving some

vertical
component to the antenna) does not make it a vertical-oriented antenna.

It
is not. It does have less directionality because of it's vertical

component,
and slightly wider bandwidth than a pure horizontal half wave dipole.


No, actually it has less bandwidth. Look it up!

It is
also less efficient.


You get back to me after you go to 'antenna school'! And, after you

finally
figure out the difference between 'horizontal' and 'vertical'.

I don't think I ever really mentioned a 'horizontal inverted vee'...

You really need to pick up an antenna book or two and actually go out and

build
some stuff.

Please, go back and read the original posters comments and actually try to
envision what he was proposing, which would seem to be a 'horizontal vee'.

At any rate, using an 'inverted vee', or a 'horizontal vee' dipole antenna

for
general shortwave listening is simply a bad idea.

Your inexperience is certainly showing this morning, Jack.

dxAce
Michigan
USA


Steve,

Here are your exact words to Dr. Artaud:

"An inverted 'V' itself would be vertical... a horizontal 'V' I think is
what you
envision."

Now as I tried to kindly point out before, you are mistaken in calling that
horizontal as compared to some imaginary and "normally vertical
inverted-vee". Of course it's horizontal, and my question to you was "what
other kind is there"? Which you have failed to answer. I'm still waiting to
hear about this vertical-inverted-vee you're touting. I've been to some
antenna schools, and I guess I missed the day they covered your
vertical-inverted-vee.

Jack


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