Advice on antenna and installation
 

On Nov 7, 11:50 am, Wes Newell wrote:
On Wed, 07 Nov 2007 09:19:12 -0800, larkmore wrote:
Thanks for the info all.

Any additional comments on the grounding/lightning protection question?
I don't want to turn the thing into a lightning rod, but don't know what
the accepted installation practice is. Any takers? -Will

If you look at your TV/VCR/Other manual, you'll find they all say the
antenna must be grounded. There are probably codes that say the same in
your city/state. What you do is up to you. I haven't grounded mine since
1969 after my grounded antenna was hit twice. Maybe it's just coincidence
that my ungrounded antenna hasn't been hit in the last 38 years.:-)
This is not a recommendation of either way. You decide.

--
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I have to confess I have not had a 'grounded' antenna in 20 years and
am not convinced its a good thing. In California lightning is not that
common and there are trees and power poles nearby that are taller than
the antenna so I don't think its that big a risk. I should find the
ham operator not far from here as his antenna is on a tower on a
modest hill to find out if his rig has been hit.

I had to use a a galvanic isolator on the coax between the 2 rooms the
multiple computers are in to prevent audio hum from a ground loop. The
2 rooms were built 40 years apart and are on different power panels
though there is only one feed into the house.

GG

Advice on antenna and installation
 

"G-squared" wrote in message
oups.com...
On Nov 7, 11:50 am, Wes Newell wrote:
On Wed, 07 Nov 2007 09:19:12 -0800, larkmore wrote:
Thanks for the info all.

Any additional comments on the grounding/lightning protection question?
I don't want to turn the thing into a lightning rod, but don't know
what
the accepted installation practice is. Any takers? -Will

If you look at your TV/VCR/Other manual, you'll find they all say the
antenna must be grounded. There are probably codes that say the same in
your city/state. What you do is up to you. I haven't grounded mine since
1969 after my grounded antenna was hit twice. Maybe it's just coincidence
that my ungrounded antenna hasn't been hit in the last 38 years.:-)
This is not a recommendation of either way. You decide.

--
Want the ultimate in free OTA SD/HDTV Recorder?http://mythtv.org
My Tivo Experiencehttp://wesnewell.no-ip.com/tivo.htm
Tivo HD/S3 comparedhttp://wesnewell.no-ip.com/mythtivo.htm
AMD cpu helphttp://wesnewell.no-ip.com/cpu.php

I have to confess I have not had a 'grounded' antenna in 20 years and
am not convinced its a good thing. In California lightning is not that
common and there are trees and power poles nearby that are taller than
the antenna so I don't think its that big a risk. I should find the
ham operator not far from here as his antenna is on a tower on a
modest hill to find out if his rig has been hit.

I had to use a a galvanic isolator on the coax between the 2 rooms the
multiple computers are in to prevent audio hum from a ground loop. The
2 rooms were built 40 years apart and are on different power panels
though there is only one feed into the house.

GG


Whether you think it is needed or not, it is required by electrical codes in
the USA that ANY incoming lines be grounded to the electrical service
ground. It simply seems foolish not to, IMO. But then I live in north
central Florida and have serviced hundreds of systems that were struch by
lightning and not properly grounded.

Leonard

Advice on antenna and installation
 

On Nov 8, 4:06 am, "Leonard Caillouet" wrote:
"G-squared" wrote in message
snip
I have to confess I have not had a 'grounded' antenna in 20 years
and
am not convinced its a good thing. In California lightning is not
that
common and there are trees and power poles nearby that are taller
than
the antenna so I don't think its that big a risk. I should find
the
ham operator not far from here as his antenna is on a tower on a
modest hill to find out if his rig has been hit.

I had to use a a galvanic isolator on the coax between the 2
rooms the
multiple computers are in to prevent audio hum from a ground
loop. The
2 rooms were built 40 years apart and are on different power
panels
though there is only one feed into the house.

GG

Whether you think it is needed or not, it is required by electrical
codes in
the USA that ANY incoming lines be grounded to the electrical
service
ground. It simply seems foolish not to, IMO. But then I live in
north
central Florida and have serviced hundreds of systems that were
struch by
lightning and not properly grounded.

Leonard

After seeing how a lightning bolt explodes a tree trunk, those little
ground wires don't 'strike' me as being more than a decoration.
Causing ground loops within the system seems more of a problem but
maybe because that is every day.

GG

Advice on antenna and installation
 

"Leonard Caillouet" wrote:

"G-squared" wrote in message
roups.com...
On Nov 7, 11:50 am, Wes Newell wrote:
On Wed, 07 Nov 2007 09:19:12 -0800, larkmore wrote:
Thanks for the info all.

Any additional comments on the grounding/lightning protection question?
I don't want to turn the thing into a lightning rod, but don't know
what
the accepted installation practice is. Any takers? -Will

If you look at your TV/VCR/Other manual, you'll find they all say the
antenna must be grounded. There are probably codes that say the same in
your city/state. What you do is up to you. I haven't grounded mine since
1969 after my grounded antenna was hit twice. Maybe it's just coincidence
that my ungrounded antenna hasn't been hit in the last 38 years.:-)
This is not a recommendation of either way. You decide.

--
Want the ultimate in free OTA SD/HDTV Recorder?http://mythtv.org
My Tivo Experiencehttp://wesnewell.no-ip.com/tivo.htm
Tivo HD/S3 comparedhttp://wesnewell.no-ip.com/mythtivo.htm
AMD cpu helphttp://wesnewell.no-ip.com/cpu.php

I have to confess I have not had a 'grounded' antenna in 20 years and
am not convinced its a good thing. In California lightning is not that
common and there are trees and power poles nearby that are taller than
the antenna so I don't think its that big a risk. I should find the
ham operator not far from here as his antenna is on a tower on a
modest hill to find out if his rig has been hit.

I had to use a a galvanic isolator on the coax between the 2 rooms the
multiple computers are in to prevent audio hum from a ground loop. The
2 rooms were built 40 years apart and are on different power panels
though there is only one feed into the house.

GG


Whether you think it is needed or not, it is required by electrical codes in
the USA that ANY incoming lines be grounded to the electrical service
ground. It simply seems foolish not to, IMO. But then I live in north
central Florida and have serviced hundreds of systems that were struch by
lightning and not properly grounded.

Leonard


leo

you could not be any more totally correct.....

I put up with constructive debates about various DVD formats, or
upscalers, or any dam other thing that doesn't directly threaten
somebodies life.

But proposing that you should not earth ground a piece of metal
sticking up from the top of ones house,,because your "opinion" thinks
it doesn't need to be done, is insanely stupid, and verging on
criminally irresponsible.

Thanks for posting,,,,hope many closed minds on this group listen and
ground, before worst happens.

Advice on antenna and installation
 

On Fri, 09 Nov 2007 01:30:57 +0000, common_ sense wrote:

But proposing that you should not earth ground a piece of metal sticking
up from the top of ones house,,because your "opinion" thinks it doesn't
need to be done, is insanely stupid, and verging on criminally
irresponsible.

So then I should go up on the roof and ground the metal entry pole that
goes into the attic. Then I should also ground the metal wind turbines.
And lets not forget the all metal chimney cover at the highest location.
You're a moron.

--
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My Tivo Experience http://wesnewell.no-ip.com/tivo.htm
Tivo HD/S3 compared http://wesnewell.no-ip.com/mythtivo.htm
AMD cpu help http://wesnewell.no-ip.com/cpu.php

Advice on antenna and installation
 

On Nov 8, 11:28 am, G-squared wrote:
After seeing how alightningbolt explodes a tree trunk, those little
ground wires don't 'strike' me as being more than a decoration.
Causing ground loops within the system seems more of a problem but
maybe because that is every day.

G-squared knows only because he feels? One damning indication? No
numbers. A responsible source provides numbers for a wire four time
smaller than those "little ground wires":
... consider that a bare 18 AWG (1 mm diameter) copper wire, in
air, normally will conduct at least 10 amperes safely, with very low
self-heating temperature rise. If the current slowly rises, the
temperature will increase until the melting temperature of 1065° C
(1950° F) is achieved at about 83 A. This same temperature could
be reached "instantly" by an 8x20 s pulse at a current of 61 kA.

Above numbers from a 1 Oct 2007 professional engineering publication
(Electrical Engineering Times); not from random speculation. That
"little ground wire" can be expected to conduct 200,000 amps which is
ten times more than current from the typically lightning bolt.

G-squared should have been asking a question - not posting
challenges based upon speculation without experience. That "little
ground wire" is proven sufficient by fundamental theory and by 100+
years of experience all over world. Oh. And it is also required by
code.

Advice on antenna and installation
 

On Nov 9, 2:12 am, Wes Newell wrote:
So then I should go up on the roof and ground the metal entry pole that
goes into the attic. Then I should also ground the metal wind turbines.
... You're a moron.

Wes Newell's posts are repeatedly justified by mockery rather than
science. From another thread where Wes makes the same claims:
On Nov 6, 3:29 am, Wes Newell wrote:
I never advised anyone of anything. I only provided my experiences
and beliefs. I'll just say that my ungrounded antenna has not been hit
bylightningin the last 38 years. In the year or two prior to that when it
was grounded, it was hit twice, causing considerable damage.

The logic implied by Wes Newell's example also proved Saddam had
WMDs. First the example violates a fundamental principle from
science. To know anything, one must have grasp of the fundamental
principles involved as well as experimental evidence. What Wes has
posted (disconnecting earth grounds) violates well proven science and
electrical principles.

To paraphrase Wes, I ran many stop signs and never had a crash. But
when I was stopped at a stop sign, someone hit me. That proves that
stopping at stop signs is dangerous. So I always run stop signs.

Eliminate both damage and threats to human life by earthing the
antenna. That is obvious even from science 100 years ago. Consult
what professionals do to eliminate damage. Someone even removed
grounds for same reasons that Wes Newell has posted: "Proper Copper
Grounding Systems Stops Lightning Damage at Nebraska FM Station" at
http://www.copper.org/applications/e.../nebraska.html
Based on a belief that "too much" grounding was attracting
lightning strikes, grounding connections on the tower's six
sets of guy wires had been disconnected sometime in the
past. This action may, in fact, have helped direct lightning
discharge current down the antenna tower itself, bringing
the strike closer to the studio/transmitter building.

The original request was about installing grounds for protection.
An application note entitled "The Need for Coordinated Protection"
demonstrates the principles:
http://www.erico.com/public/library/...es/tncr002.pdf

Review it again to appreciate some often overlooked details. The
antenna tower and building are treated as if separate structures. Any
wire entering a structure must first connect to earth ground either
directly or via a protector. The antenna tower has its own single
point earth ground. To enhance protection (because a wire connects
building to tower), then single point grounds for both structures are
interconnected with a buried ground wire.

Even an underground (telephone) wire must meet same earthing
requirements as an overhead wire. Each entering wire in every cable
must connect short (distance is critical) to the structure's earthing
electrode before entering that structure (antenna tower or building).

Advice on antenna and installation
 

On Nov 9, 7:45 pm, w_tom wrote:
On Nov 8, 11:28 am, G-squared wrote:

After seeing how alightningbolt explodes a tree trunk, those
little
ground wires don't 'strike' me as being more than a decoration.
Causing ground loops within the system seems more of a problem
but
maybe because that is every day.

G-squared knows only because he feels? One damning indication?
No
numbers. A responsible source provides numbers for a wire four
time
smaller than those "little ground wires":

... consider that a bare 18 AWG (1 mm diameter) copper wire, in
air, normally will conduct at least 10 amperes safely, with very
low
self-heating temperature rise. If the current slowly rises, the
temperature will increase until the melting temperature of 1065°
C
(1950° F) is achieved at about 83 A. This same temperature could
be reached "instantly" by an 8x20 s pulse at a current of 61 kA.

Above numbers from a 1 Oct 2007 professional engineering
publication
(Electrical Engineering Times); not from random speculation. That
"little ground wire" can be expected to conduct 200,000 amps which
is
ten times more than current from the typically lightning bolt.

G-squared should have been asking a question - not posting
challenges based upon speculation without experience. That
"little
ground wire" is proven sufficient by fundamental theory and by 100+
years of experience all over world. Oh. And it is also required
by
code.

When I start with "I confess...", it hardly qualifies as a
"challenge". What kind of numbers does one do regarding lightning? The
number of hits ? The number of days it _wasn't_ hit ? Not to be snotty
or a wiseass, how much current IS in a 'typical' lightning bolt. I was
working in the transmitter building of a CBS affiliate with a 1100
foot tower when a lightning bolt hit it. The light was impressive -
considering the building had no windows and the sound was the biggest
subwoofer you could imagine. A motorist on a nearby freeway called in
and said 'the WHOLE tower turned blue !'. Is this a typical lightning
bolt or was it unusually large? Would the 18 gauge wire have conducted
the burst to ground or would it have simply vaporized?

It's not as big an issue at our house. California gets comparatively
little lightning. My antenna is only a foot higher than the chimney in
front of it. There are several trees within 50 feet that are 20+ feet
taller.

GG

Advice on antenna and installation
 

Guys,
please... for next time....

Misspell words like grounding/lightning surge, and especially
suppressor/protector.

Posters in other groups already resort to this to avoid you-know-who's
search engine from chasing down their discussions and infesting them with
his Jehovah's Watchtower grounding deliriums.


--
"There's nothing on it worthwhile, and we're not going to watch it in this
household, and I don't want it in your intellectual diet."
- Philo T. Farnsworth

Advice on antenna and installation
 

On Nov 9, 11:18 pm, G-squared wrote:
... What kind of numbers does one do regarding lightning? The
number of hits ? The number of days it _wasn't_ hit ? ...
Would the 18 gauge wire have conducted the burst to ground
or would it have simply vaporized?

The average lightning strike is 20,000 amps. Since it is a current
source, then voltage will only increase as necessary to make that
current flow. Any most conductive path to earth means less energy
dissipated in the conductor and more energy dissipated harmlessly in
earth.

We don't use 18 AWG wires for earthing even though that small wire
would be sufficient in some cases. We want a wire that is sufficient
for most every direct strike. In AC electric systems, the same ground
wire required for post 1990 National Electrical Code will be more than
sufficient to conduct a direct lightning strike. For telephones, a 12
AWG wire is sufficient.

The rare 200,000 amp strike probably will never be observed by in
their entire life. That 6 AWG should be sufficient (and hot) even
during that most rare event.

Most all trees (95%) struck by lightning have no apparent
indication. Lightning strikes are that common and that unknown.
However a lightning strike that does ignite sugars inside the tree can
create an explosive event. A spark plug only in a car also does not
have sufficient energy to move the car.

How frequent are such events? On average, maybe once every seven
years. Even less in CA. However that number can change significantly
even in the same town. Geology does much to affect that number. One
radio station in the hills over San Jose suffered massive transmitter
damage because lightning connected PG&E 33K volts through the
transformer into their 240 power lines. Just another example of why
earthing of transformers are so important and why that low CA number
can be high in some locations.

In FL where lightning is more serious, then better earthing is
installed. A routine use of Ufer grounds is demonstrated in these
pictures:
http://members.aol.com/gfretwell/ufer.jpg
Major protection costs so little when planned and installed before the
footings are poured. But we still build homes as if the transistor
did not exist. Therefore protection is installed almost as an
afterthought - the earth ground rod.

What determines damage? Well how good is the earthing? Better
earthing with a shortest connection to that earthing means no damage.
Such threats are rare in so many locations. But the simplest
protection costs so little if we integrate an earthing system into
construction; or follow some simple rules such as all incoming wires
must enter and be earthed at the same location. An inexpensive
protection system (proper earthing) means lightning damage would not
exist.

That applies to the antenna as well. Not only should the antenna be
grounded (for human safety and lighting protection). That antenna
wire should route down to the single point earth ground, connect using
a ground block, then rise back up to enter the building.

Is this practical? Well, what is lightning's history in that
neighborhood for the past ten years?