[time-nuts] GPS antenna selection — lightning

[Hank Riley via time-nuts]

>From UL "Lightning Protection (2016):

"When we look at a Lightning Protection System in its most elementary form, it 
is quite simple. An air terminal(s) to attract and catch a lightning strike, a 
low resistance conducting cable that connects the air terminal to the earth 
using a conducting electrode and provide a pathway to dissipate the high energy 
into the earth. This system provides protection for the structure."
http://www.ul.com/wp-content/uploads/2014/04/LightningProtectionAG.pdf
So plain lightning rods do not operate to prevent strikes.

The notion that even various exotic spiny gizmos being marketed by a handful of 
companies, can, by dissipating charges or by other mechanisms, minimize or 
prevent lightning strikes to structures where they're installed has been 
discredited.  Or, to be conservative, the manufacturers' claims of 
lightning-prevention-by-charge dissipation devices have not been supported by 
real world tests.
There is a wealth of research in the literature on the subject of 
"unconventional methods" of lightning protection; this article from the 
Bulletin of the American Meteorological Society is a nice treatment and survey 
with many technical references.
http://www.lightningsafety.com/nlsi_lhm/Uman_Rakov.pdf
Hank




   

  
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Re: [time-nuts] GPS antenna selection — lightning

[Eric Scace]

Unfortunately, an antenna, cable, or piece of electronics located indoors is 
just as susceptible to lightning surges as one that is outdoors.

Lightning-induced surges couple into these systems electromagnetically across a 
wide range (VLF to SHF) of frequencies. When you think about your home from an 
electromagnetic viewpoint, just imagine your structure with all non-conductive 
materials absent. For a typical wood or brick/stone house in North America, 
what you are left with is:
metal plumbing pipes and fixtures, with their geometry suspended in space
house wiring, CATV, Ethernet, and telephone cabling, and their service drops, 
all suspended in space
electrical & electronic circuits of every kind (WiFi note, computer, 
appliances), their power supplies and AC power cords, also suspended in space
metal furniture? That’s hanging out there, suspended in space, too.
any I-beam or other steel structural elements, some random aluminum flashing, 
door knobs, and other similar metal construction materials used in the home.
That is what an electromagnetic pulse sees as it approaches and sweeps over 
your home… all hovering over a lossy ground plane (earth) its varying 
dielectric constant.. Each one of those pieces of metal, hanging in space, is 
an unintentional antenna that experiences voltage differentials and current 
flows.

A GPS antenna and its coax line that is installed next to a window is no 
different from the same antenna/coax installed one meter outside the window… or 
10 meters away outside the window. All three installations are effectively 
“outdoors” from an electromagnetic viewpoint, and all three need effective 
surge protection from lightning-, cloud-, and precipitation-induced voltage 
surges.

(N.B.: Snow can be particularly bad for voltage surges. I’ve seen thousands of 
volts per meter potential differences in moderate-to-heavy snowfall that 
produced very significant current flows on cables.)

Surge protection for your antenna, its attachment to your receiver(s), AC/DC 
power supply lines, and any other signal lines of significant length is cheap 
insurance.

My continuously-operating electronics lives in an enclosed rack cabinet — not 
too much worse than a proper Faraday cage. Every cable entering the cabinet has 
surge protection at the point of entry. The cabinet is bonded to earth ground 
by 2” copper flashing. In the past this system lived 22 years on a mountaintop 
home, 1200 ft above surrounding terrain. Lots of thunderstorms — zero 
damage/disruptions during that time… a sample size of one, admittedly, but 
during the first 18 months at that site I had two lightning-surge damaging 
events before I got serious about protection.

I have equipment at a coastal site with multiple 130-ft towers. That site had 
damage events every 2 years or so — even when cables to the “outside” were 
disconnected, and AC mains power was shut off at the main circuit breaker box. 
After implementing comprehensive surge protection, we have had zero damage over 
the last 12 years.

— Eric

> On 2016 Aug 04, at 19:46 , Bob Camp  wrote:
> 
>>> Grounding the antenna is always a good idea.
>> 
>>> A surge suppressor in the line could save you some
>>> real cost if there is a lightning strike.
>> 
>> I did a quick search for SMA/BNC/TNC based surge
>> protectors and not much did come up, any suggestions
>> what to use there?
> 
> There are a *lot* of them on eBay. Many of them have N connectors on them.
> 
>> 
>>> I don’t know about Austria, but here in the US,
>>> both are required.
>> 
>> Outside definitely, "inside" I'm not sure, but it
>> won't hurt to have additional protection for the
>> receiver(s).
> 
> It is a good bet that the antenna will be outside. I’d plan it that way.



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Re: [time-nuts] GPS antenna selection — lightning

[Bob Camp]

Hi

A ten foot long antenna cable is no more or less an issue indoors than a ten 
foot serial cable
to a laptop or a ten foot test lead running off of a DVM. They all will pick up 
a spike if the field
is strong enough. If you are in a high risk location, then yes you will need to 
go to extremes
for all of those cables. In some cases the only real answer is an external 
faraday cage around
the entire structure (plus a lot of other stuff).  

Bob

> On Aug 5, 2016, at 10:37 AM, Eric Scace  wrote:
> 
> Unfortunately, an antenna, cable, or piece of electronics located indoors is 
> just as susceptible to lightning surges as one that is outdoors.
> 
> Lightning-induced surges couple into these systems electromagnetically across 
> a wide range (VLF to SHF) of frequencies. When you think about your home from 
> an electromagnetic viewpoint, just imagine your structure with all 
> non-conductive materials absent. For a typical wood or brick/stone house in 
> North America, what you are left with is:
> metal plumbing pipes and fixtures, with their geometry suspended in space
> house wiring, CATV, Ethernet, and telephone cabling, and their service drops, 
> all suspended in space
> electrical & electronic circuits of every kind (WiFi note, computer, 
> appliances), their power supplies and AC power cords, also suspended in space
> metal furniture? That’s hanging out there, suspended in space, too.
> any I-beam or other steel structural elements, some random aluminum flashing, 
> door knobs, and other similar metal construction materials used in the home.
> That is what an electromagnetic pulse sees as it approaches and sweeps over 
> your home… all hovering over a lossy ground plane (earth) its varying 
> dielectric constant.. Each one of those pieces of metal, hanging in space, is 
> an unintentional antenna that experiences voltage differentials and current 
> flows.
> 
> A GPS antenna and its coax line that is installed next to a window is no 
> different from the same antenna/coax installed one meter outside the window… 
> or 10 meters away outside the window. All three installations are effectively 
> “outdoors” from an electromagnetic viewpoint, and all three need effective 
> surge protection from lightning-, cloud-, and precipitation-induced voltage 
> surges.
> 
> (N.B.: Snow can be particularly bad for voltage surges. I’ve seen thousands 
> of volts per meter potential differences in moderate-to-heavy snowfall that 
> produced very significant current flows on cables.)
> 
> Surge protection for your antenna, its attachment to your receiver(s), AC/DC 
> power supply lines, and any other signal lines of significant length is cheap 
> insurance.
> 
> My continuously-operating electronics lives in an enclosed rack cabinet — not 
> too much worse than a proper Faraday cage. Every cable entering the cabinet 
> has surge protection at the point of entry. The cabinet is bonded to earth 
> ground by 2” copper flashing. In the past this system lived 22 years on a 
> mountaintop home, 1200 ft above surrounding terrain. Lots of thunderstorms — 
> zero damage/disruptions during that time… a sample size of one, admittedly, 
> but during the first 18 months at that site I had two lightning-surge 
> damaging events before I got serious about protection.
> 
> I have equipment at a coastal site with multiple 130-ft towers. That site had 
> damage events every 2 years or so — even when cables to the “outside” were 
> disconnected, and AC mains power was shut off at the main circuit breaker 
> box. After implementing comprehensive surge protection, we have had zero 
> damage over the last 12 years.
> 
> — Eric
> 
>> On 2016 Aug 04, at 19:46 , Bob Camp  wrote:
>> 
 Grounding the antenna is always a good idea.
>>> 
 A surge suppressor in the line could save you some
 real cost if there is a lightning strike.
>>> 
>>> I did a quick search for SMA/BNC/TNC based surge
>>> protectors and not much did come up, any suggestions
>>> what to use there?
>> 
>> There are a *lot* of them on eBay. Many of them have N connectors on them.
>> 
>>> 
 I don’t know about Austria, but here in the US,
 both are required.
>>> 
>>> Outside definitely, "inside" I'm not sure, but it
>>> won't hurt to have additional protection for the
>>> receiver(s).
>> 
>> It is a good bet that the antenna will be outside. I’d plan it that way.
> 
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Re: [time-nuts] GPS antenna selection — lightning

[Ian Stirling]

On 08/05/2016 01:45 PM, Bob Camp wrote:


A ten foot long antenna cable is no more or less an issue indoors than a ten 
foot serial cable
to a laptop or a ten foot test lead running off of a DVM. They all will pick up 
a spike if the field
is strong enough. If you are in a high risk location, then yes you will need to 
go to extremes
for all of those cables. In some cases the only real answer is an external 
faraday cage around
the entire structure (plus a lot of other stuff).


  My outside GPS aerial came with the NTBW50AA that's still available
from RDR Electronics. It is on a plastic pole tied to the corner of my
deck and is about 12 feet above the ground. It works with the Lucent
RFTG-u pair as well. The 70 ohm cable is about 40 feet long and both
GPSDOs lock quickly from cold in my cellar lab/shack.

  My first venture with GPS was with my Trimble Flightmate Pro that
I bought in October 1993. I knew GPS was supposed to be a precise time
signal. I had built and programmed a Science of Cambridge SC/MP
(INS8060) based computer that decoded the MSF Rugby (no longer there)
60 kHz signal in 1979, still using it in 1994. Comparing it to the
received GPS time on the Trimble, I was dismayed. My records show
that on 1994 June 23 1700 UTC, GPS, or the Trimble, was a whopping
3 seconds slow,vbehind. 1994 July 03 1538 UTC, zero, seemed to be
synchronous. Same day, 1545, 1/2 a second slow. 1552, 2 seconds slow.
1556 1/2 a second slow. I suspect this was due to Selective Availability
that was not turned off until President Clinton ordered it off
in May 2000.

  I have a Navsync CW12-TIM that I bought in 2009. Its diminutive
antenna sticks magnetically to a steel filing cabinet in my office.
I get a good signal and lock there.

In August 2003, I put my hand out of the back door to test the rain.
A lightning bolt split a tree 60 feet away - my wife called me Thor
for many years. The doorbell rang, the garage door control board was
fried and needed replacing, a router in my upstairs office was
blackened, and in 2003, every television and computer monitor in the
house was a CRT - every one of them had to go through several degaussing
sessions.

Best wishes,
Ian, G4ICV, AB2GR
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Re: [time-nuts] GPS antenna selection — lightning

[Attila Kinali]

Hi Eric,

On Fri, 5 Aug 2016 10:37:28 -0400
Eric Scace  wrote:

> A GPS antenna and its coax line that is installed next to a window is no 
> different from the same antenna/coax installed one meter outside the window… 
> or 10 meters away outside the window. All three installations are 
> effectively “outdoors” from an electromagnetic viewpoint, and all three need 
> effective surge protection from lightning-, cloud-, and precipitation-
> induced voltage surges.

Please please please do NOT spread dangerous information like this!

While it is true, that an indoor antenna is suceptible to surges like
an outdoor antenna, it is not true that an outdoor antenna is equivalent
to an indoor antenna when it comes to lightning protection. 

Because an outdoor antenna can be _directly_ hit by a lightning.

To protect the house and its inhabitants from the lightning strike,
an external antenna needs to be either lower than any lightning rod
and within its 45m ball or needs its own conductor and grounding
to discharge any lightning energy and thus preventing it from following
the antenna cable into the house.

Please be aware that the grounding of the antenna is not to protect
the equipment from surges, but to prevent conduction of the lightning
into the house that could cause electrocution and fires. 

Attila Kinali

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] GPS antenna selection — lightning

[Gary E. Miller]

Yo Attila!

On Fri, 5 Aug 2016 22:51:06 +0200
Attila Kinali  wrote:

> While it is true, that an indoor antenna is suceptible to surges like
> an outdoor antenna, it is not true that an outdoor antenna is
> equivalent to an indoor antenna when it comes to lightning
> protection. 

I agree there are differences.  But not as mmuch as you think.

> Because an outdoor antenna can be _directly_ hit by a lightning.

And so can an indoor antetnna.  I live it lightning country, and it is
common for a lightning bolt to travel right through an asphalt roof to
hit metal pipes and/or wire inside a house.

I have seen this many times, it has happened to my next door neighbor and
to my son.  If you are lucky your homeowners insurance will cover a lot of
the damage.

> Please be aware that the grounding of the antenna is not to protect
> the equipment from surges, but to prevent conduction of the lightning
> into the house that could cause electrocution and fires. 

A direct hit on an antenna will laugh at your surge protector.  Nothing
at all can protect your electrical system from a direct hit.

I have seen 440V main switchboards exploded from lightning hits.  The
mess is incredible.  The switchboard case looks like a large bomb went off
inside and the cover leaves a dent on the far wall.

The surge protector on your antenna coax will try to limit the static
voltage on the center conductor to about 1,500V.  Now you have turned
your antenna into a passable lightning rod.

> To protect the house and its inhabitants from the lightning strike,
> an external antenna needs to be either lower than any lightning rod
> and within its 45m ball or needs its own conductor and grounding
> to discharge any lightning energy and thus preventing it from following
> the antenna cable into the house.

If you have any doubt about lightning you need to get some lightning rods
on your roof.  A usually passable solution is to run #8 wire from your
offical building ground directly up to an antenna mast or two on your
roof.  Best if it can be done with zero splices.

The point of the lightning rod is not to dissipate a lightning strike,
nothing can do that.  Instead it bleeds away static before it becomes
a lightning strike.

In the midwest in the winter the humidity in a house can get well below
5% and 1,500V of statis is quite common.  So indoor surge protectors
can also be useful.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588


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Re: [time-nuts] GPS antenna selection — lightning

[new]

Flying a plane with a plexiglas windshield through a snowstorm will give 
you a lightning show on your windshield.


Willy


On 8/5/2016 10:37 AM, Eric Scace wrote:

Unfortunately, an antenna, cable, or piece of electronics located indoors is 
just as susceptible to lightning surges as one that is outdoors.

Lightning-induced surges couple into these systems electromagnetically across a 
wide range (VLF to SHF) of frequencies. When you think about your home from an 
electromagnetic viewpoint, just imagine your structure with all non-conductive 
materials absent. For a typical wood or brick/stone house in North America, 
what you are left with is:
metal plumbing pipes and fixtures, with their geometry suspended in space
house wiring, CATV, Ethernet, and telephone cabling, and their service drops, 
all suspended in space
electrical & electronic circuits of every kind (WiFi note, computer, 
appliances), their power supplies and AC power cords, also suspended in space
metal furniture? That’s hanging out there, suspended in space, too.
any I-beam or other steel structural elements, some random aluminum flashing, 
door knobs, and other similar metal construction materials used in the home.
That is what an electromagnetic pulse sees as it approaches and sweeps over 
your home… all hovering over a lossy ground plane (earth) its varying 
dielectric constant.. Each one of those pieces of metal, hanging in space, is 
an unintentional antenna that experiences voltage differentials and current 
flows.

A GPS antenna and its coax line that is installed next to a window is no 
different from the same antenna/coax installed one meter outside the window… or 
10 meters away outside the window. All three installations are effectively 
“outdoors” from an electromagnetic viewpoint, and all three need effective 
surge protection from lightning-, cloud-, and precipitation-induced voltage 
surges.

(N.B.: Snow can be particularly bad for voltage surges. I’ve seen thousands of 
volts per meter potential differences in moderate-to-heavy snowfall that 
produced very significant current flows on cables.)

Surge protection for your antenna, its attachment to your receiver(s), AC/DC 
power supply lines, and any other signal lines of significant length is cheap 
insurance.

My continuously-operating electronics lives in an enclosed rack cabinet — not 
too much worse than a proper Faraday cage. Every cable entering the cabinet has 
surge protection at the point of entry. The cabinet is bonded to earth ground 
by 2” copper flashing. In the past this system lived 22 years on a mountaintop 
home, 1200 ft above surrounding terrain. Lots of thunderstorms — zero 
damage/disruptions during that time… a sample size of one, admittedly, but 
during the first 18 months at that site I had two lightning-surge damaging 
events before I got serious about protection.

I have equipment at a coastal site with multiple 130-ft towers. That site had 
damage events every 2 years or so — even when cables to the “outside” were 
disconnected, and AC mains power was shut off at the main circuit breaker box. 
After implementing comprehensive surge protection, we have had zero damage over 
the last 12 years.

— Eric


On 2016 Aug 04, at 19:46 , Bob Camp  wrote:


Grounding the antenna is always a good idea.
A surge suppressor in the line could save you some
real cost if there is a lightning strike.

I did a quick search for SMA/BNC/TNC based surge
protectors and not much did come up, any suggestions
what to use there?

There are a *lot* of them on eBay. Many of them have N connectors on them.


I don’t know about Austria, but here in the US,
both are required.

Outside definitely, "inside" I'm not sure, but it
won't hurt to have additional protection for the
receiver(s).

It is a good bet that the antenna will be outside. I’d plan it that way.



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Re: [time-nuts] GPS antenna selection — lightning

[Alexander Pummer]

lightening protection:

http://www.ul.com/wp-content/uploads/2014/04/LightningProtectionAG.pdf

73
KJ6UHN
Alex

On 8/5/2016 1:51 PM, Attila Kinali wrote:

Hi Eric,

On Fri, 5 Aug 2016 10:37:28 -0400
Eric Scace  wrote:


A GPS antenna and its coax line that is installed next to a window is no
different from the same antenna/coax installed one meter outside the window…
or 10 meters away outside the window. All three installations are
effectively “outdoors” from an electromagnetic viewpoint, and all three need
effective surge protection from lightning-, cloud-, and precipitation-
induced voltage surges.

Please please please do NOT spread dangerous information like this!

While it is true, that an indoor antenna is suceptible to surges like
an outdoor antenna, it is not true that an outdoor antenna is equivalent
to an indoor antenna when it comes to lightning protection.

Because an outdoor antenna can be _directly_ hit by a lightning.

To protect the house and its inhabitants from the lightning strike,
an external antenna needs to be either lower than any lightning rod
and within its 45m ball or needs its own conductor and grounding
to discharge any lightning energy and thus preventing it from following
the antenna cable into the house.

Please be aware that the grounding of the antenna is not to protect
the equipment from surges, but to prevent conduction of the lightning
into the house that could cause electrocution and fires.

Attila Kinali



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Re: [time-nuts] GPS antenna selection — lightning

[Chris Albertson]

You guys, well some of you are mixing to things

1) the building code requirement to ground an antenna is for the protection
of the building.  The building code don't care if you electronics is fried
or not.   The wire and ground rod keep the antenna mast at earth potential.


2) Those surge protectors and grounding your electronics to a common point
an al other advice then grounding the most to a rod by the nearest route
down the side of the house.  These are different things

So, outdoor antenna are different from indoor antenna in that if you indoor
antenna is struck the house is already pretty much toasted.   You still
might want a surge protector to protect the receiver.

The question is if you need to buy a $40 surge protector for your $8
Motorola Encore receiver?  But no question if you need a group wire in the
mast, even for that $8 gps receiver because that wire protects the house

Part of the equation is where you live.  In many years of living in Redondo
Beach, CA I never hear of anyone or anything being =damaged by lightening.
We don't even get lighting here but twice a year if that.   On the other
hand I had god protection on my sailboat as that 60 for aluminum mast might
be the highest thing around on the ocean for miles.  That mast has a very
solid connection straight to saltwater.  You have to evaluate the risk and
consequence.  You get different answer in Orlando Florida then I get here.
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Re: [time-nuts] GPS antenna selection — lightning

[Bob Camp]

Hi

Ummm ….. It’s a *lot* more fun to focus on the 0.001% case :)

Bob

> On Aug 5, 2016, at 9:31 PM, Chris Albertson  wrote:
> 
> You guys, well some of you are mixing to things
> 
> 1) the building code requirement to ground an antenna is for the protection
> of the building.  The building code don't care if you electronics is fried
> or not.   The wire and ground rod keep the antenna mast at earth potential.
> 
> 
> 2) Those surge protectors and grounding your electronics to a common point
> an al other advice then grounding the most to a rod by the nearest route
> down the side of the house.  These are different things
> 
> So, outdoor antenna are different from indoor antenna in that if you indoor
> antenna is struck the house is already pretty much toasted.   You still
> might want a surge protector to protect the receiver.
> 
> The question is if you need to buy a $40 surge protector for your $8
> Motorola Encore receiver?  But no question if you need a group wire in the
> mast, even for that $8 gps receiver because that wire protects the house
> 
> Part of the equation is where you live.  In many years of living in Redondo
> Beach, CA I never hear of anyone or anything being =damaged by lightening.
> We don't even get lighting here but twice a year if that.   On the other
> hand I had god protection on my sailboat as that 60 for aluminum mast might
> be the highest thing around on the ocean for miles.  That mast has a very
> solid connection straight to saltwater.  You have to evaluate the risk and
> consequence.  You get different answer in Orlando Florida then I get here.
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Re: [time-nuts] GPS antenna selection — lightning

[Glenn Little WB4UIV]

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and 
lightning.
A lot is for protection of military industrial complexes, but, there is 
a lot that pertains to us.


I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your 
property takes a hit, you want everything on your property to elevate to 
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference 
for each ground. This is a major source for disaster.


I spent seven years in lightning mitigation. I was told by professionals 
that I was wrong. The third time that their tower was struck, destroying 
all of the lights and attached equipment, they followed my 
recommendations. That was ten years ago. The three hits were within four 
months of each other. The site has been free of destructive hits since then.


73
Glenn
WB4UIV



On 8/5/2016 10:37 AM, Eric Scace wrote:

Unfortunately, an antenna, cable, or piece of electronics located indoors is 
just as susceptible to lightning surges as one that is outdoors.

Lightning-induced surges couple into these systems electromagnetically across a 
wide range (VLF to SHF) of frequencies. When you think about your home from an 
electromagnetic viewpoint, just imagine your structure with all non-conductive 
materials absent. For a typical wood or brick/stone house in North America, 
what you are left with is:
metal plumbing pipes and fixtures, with their geometry suspended in space
house wiring, CATV, Ethernet, and telephone cabling, and their service drops, 
all suspended in space
electrical & electronic circuits of every kind (WiFi note, computer, 
appliances), their power supplies and AC power cords, also suspended in space
metal furniture? That’s hanging out there, suspended in space, too.
any I-beam or other steel structural elements, some random aluminum flashing, 
door knobs, and other similar metal construction materials used in the home.
That is what an electromagnetic pulse sees as it approaches and sweeps over 
your home… all hovering over a lossy ground plane (earth) its varying 
dielectric constant.. Each one of those pieces of metal, hanging in space, is 
an unintentional antenna that experiences voltage differentials and current 
flows.

A GPS antenna and its coax line that is installed next to a window is no 
different from the same antenna/coax installed one meter outside the window… or 
10 meters away outside the window. All three installations are effectively 
“outdoors” from an electromagnetic viewpoint, and all three need effective 
surge protection from lightning-, cloud-, and precipitation-induced voltage 
surges.

(N.B.: Snow can be particularly bad for voltage surges. I’ve seen thousands of 
volts per meter potential differences in moderate-to-heavy snowfall that 
produced very significant current flows on cables.)

Surge protection for your antenna, its attachment to your receiver(s), AC/DC 
power supply lines, and any other signal lines of significant length is cheap 
insurance.

My continuously-operating electronics lives in an enclosed rack cabinet — not 
too much worse than a proper Faraday cage. Every cable entering the cabinet has 
surge protection at the point of entry. The cabinet is bonded to earth ground 
by 2” copper flashing. In the past this system lived 22 years on a mountaintop 
home, 1200 ft above surrounding terrain. Lots of thunderstorms — zero 
damage/disruptions during that time… a sample size of one, admittedly, but 
during the first 18 months at that site I had two lightning-surge damaging 
events before I got serious about protection.

I have equipment at a coastal site with multiple 130-ft towers. That site had 
damage events every 2 years or so — even when cables to the “outside” were 
disconnected, and AC mains power was shut off at the main circuit breaker box. 
After implementing comprehensive surge protection, we have had zero damage over 
the last 12 years.

— Eric


On 2016 Aug 04, at 19:46 , Bob Camp  wrote:


Grounding the antenna is always a good idea.



A surge suppressor in the line could save you some
real cost if there is a lightning strike.


I did a quick search for SMA/BNC/TNC based surge
protectors and not much did come up, any suggestions
what to use there?


There are a *lot* of them on eBay. Many of them have N connectors on them.




I don’t know about Austria, but here in the US,
both are required.


Outside definitely, "inside" I'm not sure, but it
won't hurt to have additional protection for the
receiver(s).


It is a good bet that the antenna will be outside. I’d plan it that way.




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Re: [time-nuts] GPS antenna selection — lightning

[Charles Steinmetz]

Glenn wrote:


A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.


Tisha Hayes has a big fat folder full of good stuff relating to 
"Grounding Surge and Filtering" at her dropbox site, and another one 
full of "Transient Protection Documents."  See:




Best regards,

Charles


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Re: [time-nuts] GPS antenna selection - lightning

[Glenn Little WB4UIV]

Cone of protection is addressed.
Volume 1 is theory, volume 2 is application.
The military requires 1/0 cable exterior to the building, commercial 
practice is #2AWG.

Ground rod spacing is address.

Overall a very good reference based on practical experience and backed 
with theory.


73
Glenn
WB4UIV


On 8/6/2016 1:19 AM, Bill Hawkins wrote:

Hi Glenn,

Your advice is excellent.

Seems like every time we have a lightning discussion there is no
distinction between an EMP and a direct hit.

I started work in 1960 at a blasting cap plant in upstate New York. The
powder magazines were protected by tall masts according to the "cone of
protection" theory. The angle of the cone varied between 45 and 60
degrees. The earth ground resistance of the mast was measured by a
hand-cranked device that looked like a megger but read earth resistance
to less than a tenth of an ohm. Had the lightning but never lost a
magazine.

You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
for direct hits?

I was fascinated by the idea that a simple capacitor discharge into an
inductor could be greatly enhanced by reducing the diameter of the
inductor with a conventional explosive, described in one of Stephen
Coonts' books, if my failing memory recalls correctly. And so I learned
what I could about EMP. Never built anything, just interesting behavior.

Best regards,
Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
Little WB4UIV
Sent: Friday, August 05, 2016 9:47 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts]GPS antenna selection - lightning

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and
lightning.
A lot is for protection of military industrial complexes, but, there is
a lot that pertains to us.

I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your
property takes a hit, you want everything on your property to elevate to
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference
for each ground. This is a major source for disaster.

I spent seven years in lightning mitigation. I was told by professionals
that I was wrong. The third time that their tower was struck, destroying
all of the lights and attached equipment, they followed my
recommendations. That was ten years ago. The three hits were within four
months of each other. The site has been free of destructive hits since
then.

73
Glenn
WB4UIV






--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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Re: [time-nuts] GPS antenna selection - lightning

[Clay Autery]

Is the 1987 version the latest issue available for free?

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 8/6/2016 8:46 AM, Glenn Little WB4UIV wrote:
> Cone of protection is addressed.
> Volume 1 is theory, volume 2 is application.
> The military requires 1/0 cable exterior to the building, commercial
> practice is #2AWG.
> Ground rod spacing is address.
>
> Overall a very good reference based on practical experience and backed
> with theory.
>
> 73
> Glenn
> WB4UIV
>
>
> On 8/6/2016 1:19 AM, Bill Hawkins wrote:
>> Hi Glenn,
>>
>> Your advice is excellent.
>>
>> Seems like every time we have a lightning discussion there is no
>> distinction between an EMP and a direct hit.
>>
>> I started work in 1960 at a blasting cap plant in upstate New York. The
>> powder magazines were protected by tall masts according to the "cone of
>> protection" theory. The angle of the cone varied between 45 and 60
>> degrees. The earth ground resistance of the mast was measured by a
>> hand-cranked device that looked like a megger but read earth resistance
>> to less than a tenth of an ohm. Had the lightning but never lost a
>> magazine.
>>
>> You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
>> for direct hits?
>>
>> I was fascinated by the idea that a simple capacitor discharge into an
>> inductor could be greatly enhanced by reducing the diameter of the
>> inductor with a conventional explosive, described in one of Stephen
>> Coonts' books, if my failing memory recalls correctly. And so I learned
>> what I could about EMP. Never built anything, just interesting behavior.
>>
>> Best regards,
>> Bill Hawkins
>>
>>
>> -----Original Message-----
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
>> Little WB4UIV
>> Sent: Friday, August 05, 2016 9:47 PM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts]GPS antenna selection - lightning
>>
>> A very good reference for EMP protection is MIL-HDBK-419.
>> This is downloadable for a number of web sources.
>> It is about 600 pages and is in two volumes.
>> This discusses a number of different sources of EMP such as nuclear and
>> lightning.
>> A lot is for protection of military industrial complexes, but, there is
>> a lot that pertains to us.
>>
>> I worked for a military complex that assembled nuclear missiles.
>> The site was built to this handbook specs.
>> We had no EMP related damage at the site.
>>
>> Number one rule, bond all grounds together. If something on your
>> property takes a hit, you want everything on your property to elevate to
>> the same level and the same rate.
>> If you have multiple, non bonded grounds, there is a different reference
>> for each ground. This is a major source for disaster.
>>
>> I spent seven years in lightning mitigation. I was told by professionals
>> that I was wrong. The third time that their tower was struck, destroying
>> all of the lights and attached equipment, they followed my
>> recommendations. That was ten years ago. The three hits were within four
>> months of each other. The site has been free of destructive hits since
>> then.
>>
>> 73
>> Glenn
>> WB4UIV
>>
>>
>>
>>
>

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Re: [time-nuts] GPS antenna selection - lightning

[Chris Albertson]

If you are looking for info in lightening.  University of Florida has a
huge collection and also points to many other places on the web.   They
actually do testing there, lightening occurs so reliably almost every day
in summer.  Their test tower gets many hits
http://www.lightning.ece.ufl.edu

But really, for practical purposes Ben Franklin got it pretty close to
right.  Give the lightening a good low impedance path to ground.

On Sat, Aug 6, 2016 at 8:00 AM, Clay Autery  wrote:

> Is the 1987 version the latest issue available for free?
>
> __
> Clay Autery, KY5G
> MONTAC Enterprises
> (318) 518-1389
>
> On 8/6/2016 8:46 AM, Glenn Little WB4UIV wrote:
> > Cone of protection is addressed.
> > Volume 1 is theory, volume 2 is application.
> > The military requires 1/0 cable exterior to the building, commercial
> > practice is #2AWG.
> > Ground rod spacing is address.
> >
> > Overall a very good reference based on practical experience and backed
> > with theory.
> >
> > 73
> > Glenn
> > WB4UIV
> >
> >
> > On 8/6/2016 1:19 AM, Bill Hawkins wrote:
> >> Hi Glenn,
> >>
> >> Your advice is excellent.
> >>
> >> Seems like every time we have a lightning discussion there is no
> >> distinction between an EMP and a direct hit.
> >>
> >> I started work in 1960 at a blasting cap plant in upstate New York. The
> >> powder magazines were protected by tall masts according to the "cone of
> >> protection" theory. The angle of the cone varied between 45 and 60
> >> degrees. The earth ground resistance of the mast was measured by a
> >> hand-cranked device that looked like a megger but read earth resistance
> >> to less than a tenth of an ohm. Had the lightning but never lost a
> >> magazine.
> >>
> >> You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
> >> for direct hits?
> >>
> >> I was fascinated by the idea that a simple capacitor discharge into an
> >> inductor could be greatly enhanced by reducing the diameter of the
> >> inductor with a conventional explosive, described in one of Stephen
> >> Coonts' books, if my failing memory recalls correctly. And so I learned
> >> what I could about EMP. Never built anything, just interesting behavior.
> >>
> >> Best regards,
> >> Bill Hawkins
> >>
> >>
> >> -Original Message-
> >> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
> >> Little WB4UIV
> >> Sent: Friday, August 05, 2016 9:47 PM
> >> To: Discussion of precise time and frequency measurement
> >> Subject: Re: [time-nuts]GPS antenna selection - lightning
> >>
> >> A very good reference for EMP protection is MIL-HDBK-419.
> >> This is downloadable for a number of web sources.
> >> It is about 600 pages and is in two volumes.
> >> This discusses a number of different sources of EMP such as nuclear and
> >> lightning.
> >> A lot is for protection of military industrial complexes, but, there is
> >> a lot that pertains to us.
> >>
> >> I worked for a military complex that assembled nuclear missiles.
> >> The site was built to this handbook specs.
> >> We had no EMP related damage at the site.
> >>
> >> Number one rule, bond all grounds together. If something on your
> >> property takes a hit, you want everything on your property to elevate to
> >> the same level and the same rate.
> >> If you have multiple, non bonded grounds, there is a different reference
> >> for each ground. This is a major source for disaster.
> >>
> >> I spent seven years in lightning mitigation. I was told by professionals
> >> that I was wrong. The third time that their tower was struck, destroying
> >> all of the lights and attached equipment, they followed my
> >> recommendations. That was ten years ago. The three hits were within four
> >> months of each other. The site has been free of destructive hits since
> >> then.
> >>
> >> 73
> >> Glenn
> >> WB4UIV
> >>
> >>
> >>
> >>
> >
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] GPS antenna selection - lightning

[Glenn Little WB4UIV]

The latest that I can find is 1987.
If you understand the theory and practice, you do not have to update 
your work often.
It is the works that are updated every few months that you have to worry 
about. The did not get it right the first time.


This is still an active military document.

73
Glenn
WB4UIV

On 8/6/2016 1:13 PM, Chris Albertson wrote:

If you are looking for info in lightening.  University of Florida has a
huge collection and also points to many other places on the web.   They
actually do testing there, lightening occurs so reliably almost every day
in summer.  Their test tower gets many hits
http://www.lightning.ece.ufl.edu

But really, for practical purposes Ben Franklin got it pretty close to
right.  Give the lightening a good low impedance path to ground.

On Sat, Aug 6, 2016 at 8:00 AM, Clay Autery  wrote:


Is the 1987 version the latest issue available for free?

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 8/6/2016 8:46 AM, Glenn Little WB4UIV wrote:

Cone of protection is addressed.
Volume 1 is theory, volume 2 is application.
The military requires 1/0 cable exterior to the building, commercial
practice is #2AWG.
Ground rod spacing is address.

Overall a very good reference based on practical experience and backed
with theory.

73
Glenn
WB4UIV


On 8/6/2016 1:19 AM, Bill Hawkins wrote:

Hi Glenn,

Your advice is excellent.

Seems like every time we have a lightning discussion there is no
distinction between an EMP and a direct hit.

I started work in 1960 at a blasting cap plant in upstate New York. The
powder magazines were protected by tall masts according to the "cone of
protection" theory. The angle of the cone varied between 45 and 60
degrees. The earth ground resistance of the mast was measured by a
hand-cranked device that looked like a megger but read earth resistance
to less than a tenth of an ohm. Had the lightning but never lost a
magazine.

You say MIL-HDBK-419 covers EMP. Does it also cover cone of protection
for direct hits?

I was fascinated by the idea that a simple capacitor discharge into an
inductor could be greatly enhanced by reducing the diameter of the
inductor with a conventional explosive, described in one of Stephen
Coonts' books, if my failing memory recalls correctly. And so I learned
what I could about EMP. Never built anything, just interesting behavior.

Best regards,
Bill Hawkins


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glenn
Little WB4UIV
Sent: Friday, August 05, 2016 9:47 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts]GPS antenna selection - lightning

A very good reference for EMP protection is MIL-HDBK-419.
This is downloadable for a number of web sources.
It is about 600 pages and is in two volumes.
This discusses a number of different sources of EMP such as nuclear and
lightning.
A lot is for protection of military industrial complexes, but, there is
a lot that pertains to us.

I worked for a military complex that assembled nuclear missiles.
The site was built to this handbook specs.
We had no EMP related damage at the site.

Number one rule, bond all grounds together. If something on your
property takes a hit, you want everything on your property to elevate to
the same level and the same rate.
If you have multiple, non bonded grounds, there is a different reference
for each ground. This is a major source for disaster.

I spent seven years in lightning mitigation. I was told by professionals
that I was wrong. The third time that their tower was struck, destroying
all of the lights and attached equipment, they followed my
recommendations. That was ten years ago. The three hits were within four
months of each other. The site has been free of destructive hits since
then.

73
Glenn
WB4UIV








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--
---
Glenn LittleARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIVwb4...@arrl.netAMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
---
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Re: [time-nuts] GPS antenna selection - lightning

[Chris Albertson]

On Sat, Aug 6, 2016 at 12:53 PM, Glenn Little WB4UIV <
glennmaill...@bellsouth.net> wrote:

> The latest that I can find is 1987.
> If you understand the theory and practice, you do not have to update your
> work often.
> It is the works that are updated every few months that you have to worry
> about. The did not get it right the first time.


You got that right.   For something as simple as grounding a small antenna
mast if you follow Ben Franklin's advice you will have about the same thing
as what is recommended today.Same for Newton and Einstein for 99% of
the stuff you do every day Newton got it right.

A lot of the exotic methods invented recently to protect electronics would
not apply to protecting a $50 receiver you bought on eBay or even a $1000
unit.  For example the first thing I would need to do is run a ring of 00
size wire around my house and fuse the various grounds to it.  But the cost
of having the trench dug (before even buying the wire) exceeds the cost of
the equipment it would protect.  TV sets are only $300 today.So most of
us about $10 worth of protection (a coax ground block and #12 bare wire)
and buy insurance.
-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] GPS antenna selection - lightning

[Bill Hawkins]

This thread grows old, so here's one person's summary:

There are two ways to be damaged by lightning:

1. A direct hit pumps 100 kiloamps of electrons into an ohm or so of
your local wiring. There is no way to survive a direct hit except to
implement stuff only the Military can afford. The probability is so low
(outside of Florida and mountain tops) that your homeowners insurance
may cover it.

2. A 100 KA strike goes to ground near you, with two effects:
  a. The ground resistance allows a large range of volts per meter to
kill cows but not golfers with their feet together.
  b. A mighty electromagnetic pulse (EMP) induces voltages in anything
inductive that is not shielded or twisted.

Case 'a' argues for a single point earth ground. When the ground voltage
goes up, you want all of your equipment to go up with it, as if it was
on an isolated ground plane. It seems best to use the Electric Power
Company's house ground for that reference point in your home. If you use
a UPS for a set of equipment, everything on it should ground to that UPS
(which should have a high capacity surge arrestor). You are left with
telephone cords, TV cables, and antennas as peripheral connections to
protect with surge arrestors. Marine supply stores sell rolls of 4 inch
wide copper strap for connecting the mast on the wheelhouse cabin with
the keel of fiberglass boats. This is also the ground for all electronic
equipment. The strap is considerably less inductive than a wire.

Case 'b' argues against long wires inside the area that contains the
common ground and the surge arrestors at its periphery.
Surge arrestors have energy ratings that refer to the energy of the EMP
that caused the surge. I have no idea how that relates to lightning EMP
energy so I buy the most capacity I can afford.

I used these principles in a home that had a pair of HP GPS antennas
four feet apart on a twenty foot mast of six inch plastic pipe, using N
connectors and 50 feet of RG-8 to a pair of Z3801A receivers. The
neighbor's tree took a direct hit (was split apart) less than 100 feet
away. He had extensive electrical damage originating at the outdoor
flood light six feet from the tree. I lost the GPS antenna closest to
the tree but nothing else. FWIW, I had wireless G access points
separating the area connected to the antenna from the rest of the house
network. No attempt was made to beef up the grounds.

Regards,
Bill Hawkins

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Re: [time-nuts] GPS antenna selection - lightning

[Bob Stewart]

Hi Bill,
A lot of us are hams.  The ARRL handbook has a section on grounds, including 
the need for bonding additional grounds to the power line ground.  A loop of 
heavy gauge wire around the house that has periodic 8' ground rods is seen as a 
good thing as long as it's bonded to the power line ground.  This is something 
entirely different from "multi-point ground".  It is said to provide a circle 
of protection around the house, but yea, it's a lot more complicated than that. 
 Check the handbook, or read whatever grounding documents you have access to 
and trust.

OK, I've had my say.

Bob - AE6RV
 -
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

  From: Bill Hawkins 
 To: 'Discussion of precise time and frequency measurement' 
 
 Sent: Sunday, August 7, 2016 10:06 PM
 Subject: Re: [time-nuts] GPS antenna selection - lightning
   
This thread grows old, so here's one person's summary:

There are two ways to be damaged by lightning:

1. A direct hit pumps 100 kiloamps of electrons into an ohm or so of
your local wiring. There is no way to survive a direct hit except to
implement stuff only the Military can afford. The probability is so low
(outside of Florida and mountain tops) that your homeowners insurance
may cover it.

2. A 100 KA strike goes to ground near you, with two effects:
  a. The ground resistance allows a large range of volts per meter to
kill cows but not golfers with their feet together.
  b. A mighty electromagnetic pulse (EMP) induces voltages in anything
inductive that is not shielded or twisted.

Case 'a' argues for a single point earth ground. When the ground voltage
goes up, you want all of your equipment to go up with it, as if it was
on an isolated ground plane. It seems best to use the Electric Power
Company's house ground for that reference point in your home. If you use
a UPS for a set of equipment, everything on it should ground to that UPS
(which should have a high capacity surge arrestor). You are left with
telephone cords, TV cables, and antennas as peripheral connections to
protect with surge arrestors. Marine supply stores sell rolls of 4 inch
wide copper strap for connecting the mast on the wheelhouse cabin with
the keel of fiberglass boats. This is also the ground for all electronic
equipment. The strap is considerably less inductive than a wire.

Case 'b' argues against long wires inside the area that contains the
common ground and the surge arrestors at its periphery.
Surge arrestors have energy ratings that refer to the energy of the EMP
that caused the surge. I have no idea how that relates to lightning EMP
energy so I buy the most capacity I can afford.

I used these principles in a home that had a pair of HP GPS antennas
four feet apart on a twenty foot mast of six inch plastic pipe, using N
connectors and 50 feet of RG-8 to a pair of Z3801A receivers. The
neighbor's tree took a direct hit (was split apart) less than 100 feet
away. He had extensive electrical damage originating at the outdoor
flood light six feet from the tree. I lost the GPS antenna closest to
the tree but nothing else. FWIW, I had wireless G access points
separating the area connected to the antenna from the rest of the house
network. No attempt was made to beef up the grounds.

Regards,
Bill Hawkins

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Re: [time-nuts] GPS antenna selection - lightning

[jimlux]

On 8/7/16 8:06 PM, Bill Hawkins wrote:

This thread grows old, so here's one person's summary:
 Marine supply stores sell rolls of 4 inch
wide copper strap for connecting the mast on the wheelhouse cabin with
the keel of fiberglass boats. This is also the ground for all electronic
equipment. The strap is considerably less inductive than a wire.


No - strap is about the same inductance as a wire of the same length. 
The advantage of strap is a lower RF resistance, which is important if 
the strap is part of your antenna system, because it's less resistive 
loss than a wire.


For lightning impulses, either conducted or radiated, the inductance 
dominates the voltage rise (e.g. Xl is much larger than Rac).


Strap or bar may be easier to make connections to (drill a hole in some 
1/8x1" bar, tap it, and hook your lug up)





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Re: [time-nuts] GPS antenna selection - lightning

[Bob Camp]

Hi

We tend to look at all this lighting / EMP stuff very much as a “get to the 
ground” 
sort of thing. For whatever reason the whole thought process stops once we get
to a coper weld rod driven however far into the dirt. 

If you try to operate a vertical antenna against that same rod in the middle of 
a nice dry
summer.  You will quickly find out that dirt != ground. The same fun and games
that get you a low impedance ground for your antenna also apply to a low 
impedance 
ground for your protection system. Its not an identical process, but it’s the 
same idea. 

You can argue that a good bond of everything to a single point is sufficient. 
Looking around
my house, there is most certainly *not* a single point of entry for everything. 
Various 
utilities and other wires / chunks of conductive stuff go off in a variety of 
directions. Like
most homes in the US, it’s a wood frame structure. There is no nice steel frame 
to 
tie everything to. I suppose the first step would be to tear the house down and 
re-build
it from scratch …..

Bob

> On Aug 8, 2016, at 10:00 AM, jimlux  wrote:
> 
> On 8/7/16 8:06 PM, Bill Hawkins wrote:
>> This thread grows old, so here's one person's summary:
>> Marine supply stores sell rolls of 4 inch
>> wide copper strap for connecting the mast on the wheelhouse cabin with
>> the keel of fiberglass boats. This is also the ground for all electronic
>> equipment. The strap is considerably less inductive than a wire.
> 
> No - strap is about the same inductance as a wire of the same length. The 
> advantage of strap is a lower RF resistance, which is important if the strap 
> is part of your antenna system, because it's less resistive loss than a wire.
> 
> For lightning impulses, either conducted or radiated, the inductance 
> dominates the voltage rise (e.g. Xl is much larger than Rac).
> 
> Strap or bar may be easier to make connections to (drill a hole in some 
> 1/8x1" bar, tap it, and hook your lug up)
> 
> 
> 
> 
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