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Lightning Strike - Metal Roof attracts?

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Alan D. Wilcox, W3DVX

Lightning Strike - Metal Roof attracts?

Hello,
Unusual electrical storms here on top of hill on Sunday evening (9/11).
On Saturday, the roofing contractor finished putting half of metal roof
on house. Received lightning strike to roof (I think), but saw flash
onto front walkway. Heard explosion right at my wall. Couldn't find
point of hit though. Roof was finished Monday.

Is that new metal roof a target for the next storm? Never had a
lightning strike near here before this.

For the curious: Damage was everything connected to my LAN ... Apple
MBPro, Mac Mini, MacPro I/O, router, hub, soundcard connected to K3 on
old Windows PC. The K3 ant and power were disconnected (but two audio
cables from old PC were connected to K3): my K3 is shot and on its way
to Elecraft. A Comcast TV box was shot, and the tel and Internet all
needed reset from Comcast. Still finding problems ...

Limping along with old Win-2000 PC.

Cheers, Alan

Alan D. Wilcox, W3DVX (K2-5373, K3-40)
570-321-1516
http://WilcoxEngineering.com
http://eBookEditor.net
Williamsport, PA 17701

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John Ragle

Re: Lightning Strike - Metal Roof attracts?

As far as "active" targeting goes, a flat, planar roof definitely does
not "attract" lightning. Points of attraction are high, sharp & pointed,
conductive objects that help to form the leader (ground to air) strike.
That said, lightning has a tendency to splay around and involve objects
near the leader and the multiple return strikes. I suppose heavy
grounding of your shiny new roof might be wise, as is done in the case
of high buildings. As I am sure you know, the electric field inside a
conducting sphere is zero...but a house with a metal roof is only a very
rough approximation to this ideal case (grin). I think the esthetics of
rain sounds would normally outweigh the dangers of lightning damage...my
condolences on your multiple damages (been there, done that myself). I
don't think the metal roof had much to do with them.

John Ragle -- W1ZI

On 9/14/2011 3:55 PM, Alan D. Wilcox wrote:
> Is that new metal roof a target for the next storm?

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drewko

Re: Lightning Strike - Metal Roof attracts?

In reply to this post by Alan D. Wilcox, W3DVX

I think i've posted this before: During lightning season I disconnect
everything from my K3 when it is not in use, including headphones and
key. Same goes for my PC and router. I leave no cables connected to
any of these boxes. It is a bit annoying, especially at the start of
the season when I have to get used to the disconnect/reconnect routine
all over again. But the alternative is as you have found: the rare
close strike probably means everything that is connected will get
taken out.

We also experienced a lighting storm Sun night, here 150 miles to your
east. Maybe it was just the awareness of the dreadful anniversary but
I remember thinking that it sure was some unusual sounding thunder:
the rumbles were long and building rather than quick and decaying.

73,
Drew
AF2Z

On Wed, 14 Sep 2011 15:55:31 -0400, Alan wrote:

>Hello,
>Unusual electrical storms here on top of hill on Sunday evening (9/11).
>On Saturday, the roofing contractor finished putting half of metal roof
>on house. Received lightning strike to roof (I think), but saw flash
>onto front walkway. Heard explosion right at my wall. Couldn't find
>point of hit though. Roof was finished Monday.
>
>Is that new metal roof a target for the next storm? Never had a
>lightning strike near here before this.
>
>For the curious: Damage was everything connected to my LAN ... Apple
>MBPro, Mac Mini, MacPro I/O, router, hub, soundcard connected to K3 on
>old Windows PC. The K3 ant and power were disconnected (but two audio
>cables from old PC were connected to K3): my K3 is shot and on its way
>to Elecraft. A Comcast TV box was shot, and the tel and Internet all
>needed reset from Comcast. Still finding problems ...
>
>Limping along with old Win-2000 PC.
>
>Cheers, Alan
>
>Alan D. Wilcox, W3DVX (K2-5373, K3-40)
>570-321-1516
>http://WilcoxEngineering.com
>http://eBookEditor.net
>Williamsport, PA 17701
>

k5oai

Re: Lightning Strike - Metal Roof attracts?

just curious
how many things (actual number please)
do you unplug from both your K3 and the computer/router?

I know my K3 has 14 or more cables to it
and the radio computer has to have at least that many again
the firewall computer in the other room has 6
and the router has 3
then there is the other computers
and the hub......

not saying it's not a good idea
just wondering if I should some how simplify my life?

GB & 73
K5OAI
Sam Morgan

On 9/14/2011 5:17 PM, drewko wrote:

> I think i've posted this before: During lightning season I disconnect
> everything from my K3 when it is not in use, including headphones and
> key. Same goes for my PC and router. I leave no cables connected to
> any of these boxes. It is a bit annoying, especially at the start of
> the season when I have to get used to the disconnect/reconnect routine
> all over again. But the alternative is as you have found: the rare
> close strike probably means everything that is connected will get
> taken out.
>
> We also experienced a lighting storm Sun night, here 150 miles to your
> east. Maybe it was just the awareness of the dreadful anniversary but
> I remember thinking that it sure was some unusual sounding thunder:
> the rumbles were long and building rather than quick and decaying.
>
> 73,
> Drew
> AF2Z
>
>
>
>
> On Wed, 14 Sep 2011 15:55:31 -0400, Alan wrote:
>
>> Hello,
>> Unusual electrical storms here on top of hill on Sunday evening (9/11).
>> On Saturday, the roofing contractor finished putting half of metal roof
>> on house. Received lightning strike to roof (I think), but saw flash
>> onto front walkway. Heard explosion right at my wall. Couldn't find
>> point of hit though. Roof was finished Monday.
>>
>> Is that new metal roof a target for the next storm? Never had a
>> lightning strike near here before this.
>>
>> For the curious: Damage was everything connected to my LAN ... Apple
>> MBPro, Mac Mini, MacPro I/O, router, hub, soundcard connected to K3 on
>> old Windows PC. The K3 ant and power were disconnected (but two audio
>> cables from old PC were connected to K3): my K3 is shot and on its way
>> to Elecraft. A Comcast TV box was shot, and the tel and Internet all
>> needed reset from Comcast. Still finding problems ...
>>
>> Limping along with old Win-2000 PC.
>>
>> Cheers, Alan
>>
>> Alan D. Wilcox, W3DVX (K2-5373, K3-40)
>> 570-321-1516
>> http://WilcoxEngineering.com
>> http://eBookEditor.net
>> Williamsport, PA 17701

Alan D. Wilcox, W3DVX

Re: Lightning Strike - Metal Roof attracts?

In reply to this post by Alan D. Wilcox, W3DVX

All,
Thanks for words on the roof ... kind of late in the game to do much
about that now. Don't think I want to go the "lightning rod" approach,
because even a great ground is still likely to raise hob inside the
house with ground-fault currents.

Had I unplugged the 2 audio cables to the K3, it would probably still be
alive today. My homebrew keyer was connected, and it isn't working either.

The funny part of it is that my Carolina Windom was knocked down (copper
at end was melted), but nothing inside the house was connected to the
coax, and no direct damage. The wall-wart power supplies shorted and
just one 20A circuit breaker tripped.

Dick,
Yes, the wireless approach will solve some of it. I put in a gigabit LAN
for the speed, but breaking it up sure makes a lot of sense. The new
D-Link router has wireless, so that'll work with the MBPro and Mac Mini
whenever they come back from the shop.

Cheers, Alan

Alan D. Wilcox, W3DVX (K2-5373, K3-40)
570-321-1516
http://WilcoxEngineering.com
http://eBookEditor.net
Williamsport, PA 17701

On 9/14/2011 6:04 PM, Dick Williams wrote:

> Alan,
>
> I would not think a metal roof would be any more of a "lightning rod" than
> any other structure; from what I remember, sharp pointed objects are good
> "lightning rods".
>
> Sorry to hear about all the damage there; am wondering if you have all your
> computer stuff "hard wired" to the router? If so, you might consider
> changing to a wireless router; that might at least prevent damage to your
> whole system if you take another strike.
>
> I believe that I took a strike or good static discharge on one of my towers
> during the last storm; when I plugged the disconnect from the rotor cable
> to the control box in for my M2 R2800 rotor, there was the sound of an arc
> and the display dimmed. Upon further investigation, I found one side of
> line going to the DC motor was grounded. Took the antenna and rotor down
> and after dis-assembly of the rotor, I found there are .01 and .001
> capacitors from the each side of the motor to ground. One of the .001s was
> blown in half, and the other .001 on the other motor lead had a big black
> burn mark in it (the one that ended up being shorted to ground).
>
> After further investigation for other problems, I found a blocking diode in
> one of my rotor relay control boxes for my Tailtwisters/Ham IVs was shorted.
> Interesting enough, that switch box is not connected at all (other than via
> the common ground) to the tower with the R2800 on it.
>
> Lightning can do strange things!!
>
> Dick K8ZTT
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Alan D. Wilcox
> Sent: Wednesday, September 14, 2011 1:56 PM
> To: [hidden email]
> Subject: [Elecraft] Lightning Strike - Metal Roof attracts?
>
> Hello,
> Unusual electrical storms here on top of hill on Sunday evening (9/11).
> On Saturday, the roofing contractor finished putting half of metal roof
> on house. Received lightning strike to roof (I think), but saw flash
> onto front walkway. Heard explosion right at my wall. Couldn't find
> point of hit though. Roof was finished Monday.
>
> Is that new metal roof a target for the next storm? Never had a
> lightning strike near here before this.
>
> For the curious: Damage was everything connected to my LAN ... Apple
> MBPro, Mac Mini, MacPro I/O, router, hub, soundcard connected to K3 on
> old Windows PC. The K3 ant and power were disconnected (but two audio
> cables from old PC were connected to K3): my K3 is shot and on its way
> to Elecraft. A Comcast TV box was shot, and the tel and Internet all
> needed reset from Comcast. Still finding problems ...
>
> Limping along with old Win-2000 PC.
>
> Cheers, Alan
>
> Alan D. Wilcox, W3DVX (K2-5373, K3-40)
> 570-321-1516
> http://WilcoxEngineering.com
> http://eBookEditor.net
> Williamsport, PA 17701

Don Wilhelm-4

Re: Lightning Strike - Metal Roof attracts?

In reply to this post by k5oai

An alternative to unplugging everything -- create a system where
everything will be at the same potential through a surge event and you
will have no damage.

Run a #4 (or larger) perimeter wire around your house (and any other
buildings) with a ground rod at each point where it changes direction,
connect it with #4 wire to everything metallic in your house structure
or outbuildings, and then connect it to the 3 or 4 #4 wires radiating
from each of your towers or masts - those radial wires should have
ground rods connected at intervals not exceeding twice the length of the
ground rods. (8 foot rods spaced every 16 feet, or 4 ft rods spaced at
8 foot intervals, etc.). The length of the radial rods should be at
least as long as the tower or mast is tall. Oh yes, all these grounds
must connect to the utility ground rod(s) for the house. Anything
metallic in the house (including the roof if metal) should connect to
this ground system). Install a "whole house" surge protection device at
the electrical panel. and put surge suppression devices on incoming TV
antenna, cable TV/internet lines, telco lines, etc.

In addition, all lines coming into the station should enter through a
"grounding window" (a copper or aluminum panel) where your coax
lightning protection devices are mounted, the station power comes
through this panel too with a surge protection device (do not skimp on
the quality), all telco and ethernet, rotator cables, remote antenna
switch wires, (everything entering the station). also come through this
panel and each conductor is equipped with an MOV or similar protective
device. The panel is connected to one or more ground rods (also
connected to the perimeter wire and the utility ground point) with good
low impedance ground strap (only gentle turns). In other words,
*everything* within the station has its connectivity routed through that
grounding window, and every piece of equipment in the station and within
reaching distance of the operating position is tightly bonded to that
grounding window, and all the ground wires and rods are connected to
each other.

If you do all those things, you may not have to disconnect everything
from your transceiver during a lightning storm. As an added benefit,
you may eliminate many hum sources in your station's audio system, and
the locally generated noise may be reduced.

I know all of that is not practical for some existing structures, but
take the recommendations as intended, and know where your deficiencies
are, then do what you must to protect your home and equipment. I have
some of that system in place or in-plan for the near future, but I still
do not operate during a lightning event. Each transceiver is connected
to a dummy load automatically when I remove power from the antenna relay
system for additional protection.

A bit of planning will provide you with some protection, but whatever
you install, do not depend on it with your life - there will most always
be some deficiency, so do take reasonable precautions during an
electrical storm (stay away from the operating position).

Look at the Safety section of the newer ARRL Handbooks, and review the
information on station protection at the Polyphaser website for more
detailed information. Ron Block has provided some good information
regarding these practices in QST several years ago, sorry but I cannot
recall the year, but it was a 3 part article.

73,
Don W3FPR

On 9/14/2011 7:03 PM, Sam Morgan wrote:

> just curious
> how many things (actual number please)
> do you unplug from both your K3 and the computer/router?
>
> I know my K3 has 14 or more cables to it
> and the radio computer has to have at least that many again
> the firewall computer in the other room has 6
> and the router has 3
> then there is the other computers
> and the hub......
>
> not saying it's not a good idea
> just wondering if I should some how simplify my life?
>
> GB& 73
> K5OAI
> Sam Morgan
>
> On 9/14/2011 5:17 PM, drewko wrote:
>> I think i've posted this before: During lightning season I disconnect
>> everything from my K3 when it is not in use, including headphones and
>> key. Same goes for my PC and router. I leave no cables connected to
>> any of these boxes. It is a bit annoying, especially at the start of
>> the season when I have to get used to the disconnect/reconnect routine
>> all over again. But the alternative is as you have found: the rare
>> close strike probably means everything that is connected will get
>> taken out.
>>
>> We also experienced a lighting storm Sun night, here 150 miles to your
>> east. Maybe it was just the awareness of the dreadful anniversary but
>> I remember thinking that it sure was some unusual sounding thunder:
>> the rumbles were long and building rather than quick and decaying.
>>
>> 73,
>> Drew
>> AF2Z
>>
>>
>>
>>
>> On Wed, 14 Sep 2011 15:55:31 -0400, Alan wrote:
>>
>>> Hello,
>>> Unusual electrical storms here on top of hill on Sunday evening (9/11).
>>> On Saturday, the roofing contractor finished putting half of metal roof
>>> on house. Received lightning strike to roof (I think), but saw flash
>>> onto front walkway. Heard explosion right at my wall. Couldn't find
>>> point of hit though. Roof was finished Monday.
>>>
>>> Is that new metal roof a target for the next storm? Never had a
>>> lightning strike near here before this.
>>>
>>> For the curious: Damage was everything connected to my LAN ... Apple
>>> MBPro, Mac Mini, MacPro I/O, router, hub, soundcard connected to K3 on
>>> old Windows PC. The K3 ant and power were disconnected (but two audio
>>> cables from old PC were connected to K3): my K3 is shot and on its way
>>> to Elecraft. A Comcast TV box was shot, and the tel and Internet all
>>> needed reset from Comcast. Still finding problems ...
>>>
>>> Limping along with old Win-2000 PC.
>>>
>>> Cheers, Alan
>>>
>>> Alan D. Wilcox, W3DVX (K2-5373, K3-40)
>>> 570-321-1516
>>> http://WilcoxEngineering.com
>>> http://eBookEditor.net
>>> Williamsport, PA 17701
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Dick Williams-2

Lightning Strike - Metal Roof attracts?

In reply to this post by Alan D. Wilcox, W3DVX

I have to totally disagree with Drew's (AF2Z) statement that " the rare
close strike probably means everything that is connected will get taken
out". Nothing can be further from the truth. The next three paragraphs are
quoted from WR Blocks web site (W3FPR specifically mentions Ron Block in his
rather verbose dissertation in his email below):

"Our challenge is to assemble the best amateur radio station possible, enjoy
the benefits of the hobby, and have our station operable during times of
need. This can be a significant challenge especially considering the height
of the antenna and the awesome capabilities of Mother Nature's lightning
strikes. While she may have the upper hand as far as when and how much
energy she delivers, you have the ability to influence how that energy is
diverted into the earth. Said another way, you can implement a lightning
protection plan that will protect your amateur radio station, even from a
direct strike!

The commercial radio folks have done this for years; many of them have
critical, must operate, installations in some very difficult to reach
locations. Many of the installations are located on hills or mountaintops
that afford the best area coverage and are great lightning strike targets.
They do survive direct strikes and continue to provide important services to
the communities that they serve. While this type of solution is possible
for the amateur radio station, it does cost money and it does take a
significant amount of resourcefulness, ingenuity, and effort to implement
and maintain.

The plan does work; but you must follow all of the rules, exactly. Any
violation of the rules, even just a little one, may result in a violation of
the protection plan and damage to your equipment. In some cases the damage
to a semi-protected radio station could be worse than if no protection plan
had been implemented at all. I'll start with some background and then get
into the heart of the matter."

Don's (W3FPR) is right on track. I have lived south of Denver on top of a
hill since 1993, and moderate to severe thunderstorms seem to be the rule
rather than the exception in the Spring and Summer (around 40 or so).
Though I can't say that I have ever watched one of my towers take a hit (not
in the habit of sitting by a window during a lightning storm and "standing
watch" over my towers - I normally hibernate in the shack and use the
computer while enjoying feeling the house shake with the close by lightning
strikes); one evening (wife and I were out) the fire dept told me they
responded to the house after receiving a call from a passing motorist that
he saw one of my towers being hit by lightning. They did not find any
damage, nor did I after I arrived home and checked everything out. In an
earlier post, I mentioned that I did have some damage to the M2 Orion 2800
rotor (on the 120 ft tower) and a diode in one of my Hy-Gain rotor relay
switch boxes being shorted after a storm last week. If that is the only two
"hits" I have had in 18 years, I am pretty damn lucky; according to the
charts, my 120 ft tower has a probability of being hit 2 1/2 times a year
based on the number of "thunderstorm days".

When I was erecting my "antenna farm" I was well aware of the lightning
problems associated with living on top of a hill at 6600 ft; and took the
necessary steps to minimize the risks of sustaining substantial damage to my
equipment. All I will say is I can't agree more with what W3FPR states; but
rather than try and "dig up" old QST articles, just go to Ron Blocks web
site (http://www.wrblock.com) and "click" on PAPERS. That will tell you
everything you ever wanted to know about lightning protection and what you
need to do to effectively "ground" your station.

Since I am not a big fan of "practice bleeding", I do not operate during a
storm; and I try and remember to disconnect the coax and rotor cables
(normally four - five if the 2 mtr radio is connected). However, I have to
admit that more than once I did not disconnect stuff prior to leaving and a
storm rolled through while I was gone. I can't believe that Drew disconnects
everything from his K3, PC and router; I can't imagine the amount of time
that must take having to connect and then re-connect every time it is going
to storm (I have around 14 or so connected to the K3 - it would take me at
least 15 minutes to figure out where each one goes!).

Dick K8ZTT

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Don Wilhelm
Sent: Wednesday, September 14, 2011 6:01 PM
To: [hidden email]
Subject: Re: [Elecraft] Lightning Strike - Metal Roof attracts?

An alternative to unplugging everything -- create a system where
everything will be at the same potential through a surge event and you
will have no damage.

Run a #4 (or larger) perimeter wire around your house (and any other
buildings) with a ground rod at each point where it changes direction,
connect it with #4 wire to everything metallic in your house structure
or outbuildings, and then connect it to the 3 or 4 #4 wires radiating
from each of your towers or masts - those radial wires should have
ground rods connected at intervals not exceeding twice the length of the
ground rods. (8 foot rods spaced every 16 feet, or 4 ft rods spaced at
8 foot intervals, etc.). The length of the radial rods should be at
least as long as the tower or mast is tall. Oh yes, all these grounds
must connect to the utility ground rod(s) for the house. Anything
metallic in the house (including the roof if metal) should connect to
this ground system). Install a "whole house" surge protection device at
the electrical panel. and put surge suppression devices on incoming TV
antenna, cable TV/internet lines, telco lines, etc.

In addition, all lines coming into the station should enter through a
"grounding window" (a copper or aluminum panel) where your coax
lightning protection devices are mounted, the station power comes
through this panel too with a surge protection device (do not skimp on
the quality), all telco and ethernet, rotator cables, remote antenna
switch wires, (everything entering the station). also come through this
panel and each conductor is equipped with an MOV or similar protective
device. The panel is connected to one or more ground rods (also
connected to the perimeter wire and the utility ground point) with good
low impedance ground strap (only gentle turns). In other words,
*everything* within the station has its connectivity routed through that
grounding window, and every piece of equipment in the station and within
reaching distance of the operating position is tightly bonded to that
grounding window, and all the ground wires and rods are connected to
each other.

If you do all those things, you may not have to disconnect everything
from your transceiver during a lightning storm. As an added benefit,
you may eliminate many hum sources in your station's audio system, and
the locally generated noise may be reduced.

I know all of that is not practical for some existing structures, but
take the recommendations as intended, and know where your deficiencies
are, then do what you must to protect your home and equipment. I have
some of that system in place or in-plan for the near future, but I still
do not operate during a lightning event. Each transceiver is connected
to a dummy load automatically when I remove power from the antenna relay
system for additional protection.

A bit of planning will provide you with some protection, but whatever
you install, do not depend on it with your life - there will most always
be some deficiency, so do take reasonable precautions during an
electrical storm (stay away from the operating position).

Look at the Safety section of the newer ARRL Handbooks, and review the
information on station protection at the Polyphaser website for more
detailed information. Ron Block has provided some good information
regarding these practices in QST several years ago, sorry but I cannot
recall the year, but it was a 3 part article.

73,
Don W3FPR

On 9/14/2011 7:03 PM, Sam Morgan wrote:

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

drewko

Re: Lightning Strike - Metal Roof attracts?

In reply to this post by k5oai

Well, I don't have as much as you do connected to the K3: two
antennas; counterpoise; key; headphones; power cable; occasionally
RS232 and/or audio cables.

Computer has CAT5; audio cables; printer; scanner; monitor; keyboard;
power; perhaps RS232 and audio to K3. (I can re-plug all this stuff by
feel without having to see the back of the PC; that tells you how many
times I've done it.... )

The other PC is a clunker that I'm not too worried about; i only
disconnect the power and CAT5 from it. Ethernet cards seem to be
susceptible to induced electrical charges from storms; maybe it is
just the long 60ft cable run, but one card died from lightning strike
several hundred feet away. I unplug everything from the DSL
modem/router (4 plugs including phone line and power).

This is all part of the thunderstorm season ritual, including forever
running around three story house opening windows for fresh air or
closing them again to keep the rain out.

It's a hassle but so is dealing with insurance companies, buying new
stuff and restoring computer systems. It only takes about 5 minutes to
make the rounds and unplug everything.

73,
Drew
AF2Z

On Wed, 14 Sep 2011 18:03:41 -0500, you wrote:

drewko

Re: Lightning Strike - Metal Roof attracts?

In reply to this post by Dick Williams-2

I didn't mean to imply that anyone should follow my example; I was
just relating what I do in my relatively simple station and computer
setup.

I'm not about to install a sophisticated grounding system, so
unplugging stuff is the next best option. I probably wouldn't go that
route if my setup was very much more involved or if I lived on a
mountain peak.

73,
Drew
AF2Z

On Wed, 14 Sep 2011 20:49:20 -0600, you wrote:

>
>I have to totally disagree with Drew's (AF2Z) statement that " the rare
>close strike probably means everything that is connected will get taken
>out". Nothing can be further from the truth. The next three paragraphs are
>quoted from WR Blocks web site (W3FPR specifically mentions Ron Block in his
>rather verbose dissertation in his email below):
>
>
>
>"Our challenge is to assemble the best amateur radio station possible, enjoy
>the benefits of the hobby, and have our station operable during times of
>need. This can be a significant challenge especially considering the height
>of the antenna and the awesome capabilities of Mother Nature's lightning
>strikes. While she may have the upper hand as far as when and how much
>energy she delivers, you have the ability to influence how that energy is
>diverted into the earth. Said another way, you can implement a lightning
>protection plan that will protect your amateur radio station, even from a
>direct strike!
>
>The commercial radio folks have done this for years; many of them have
>critical, must operate, installations in some very difficult to reach
>locations. Many of the installations are located on hills or mountaintops
>that afford the best area coverage and are great lightning strike targets.
>They do survive direct strikes and continue to provide important services to
>the communities that they serve. While this type of solution is possible
>for the amateur radio station, it does cost money and it does take a
>significant amount of resourcefulness, ingenuity, and effort to implement
>and maintain.
>
>The plan does work; but you must follow all of the rules, exactly. Any
>violation of the rules, even just a little one, may result in a violation of
>the protection plan and damage to your equipment. In some cases the damage
>to a semi-protected radio station could be worse than if no protection plan
>had been implemented at all. I'll start with some background and then get
>into the heart of the matter."
>
>
>
>Don's (W3FPR) is right on track. I have lived south of Denver on top of a
>hill since 1993, and moderate to severe thunderstorms seem to be the rule
>rather than the exception in the Spring and Summer (around 40 or so).
>Though I can't say that I have ever watched one of my towers take a hit (not
>in the habit of sitting by a window during a lightning storm and "standing
>watch" over my towers - I normally hibernate in the shack and use the
>computer while enjoying feeling the house shake with the close by lightning
>strikes); one evening (wife and I were out) the fire dept told me they
>responded to the house after receiving a call from a passing motorist that
>he saw one of my towers being hit by lightning. They did not find any
>damage, nor did I after I arrived home and checked everything out. In an
>earlier post, I mentioned that I did have some damage to the M2 Orion 2800
>rotor (on the 120 ft tower) and a diode in one of my Hy-Gain rotor relay
>switch boxes being shorted after a storm last week. If that is the only two
>"hits" I have had in 18 years, I am pretty damn lucky; according to the
>charts, my 120 ft tower has a probability of being hit 2 1/2 times a year
>based on the number of "thunderstorm days".
>
>When I was erecting my "antenna farm" I was well aware of the lightning
>problems associated with living on top of a hill at 6600 ft; and took the
>necessary steps to minimize the risks of sustaining substantial damage to my
>equipment. All I will say is I can't agree more with what W3FPR states; but
>rather than try and "dig up" old QST articles, just go to Ron Blocks web
>site (http://www.wrblock.com) and "click" on PAPERS. That will tell you
>everything you ever wanted to know about lightning protection and what you
>need to do to effectively "ground" your station.
>
>Since I am not a big fan of "practice bleeding", I do not operate during a
>storm; and I try and remember to disconnect the coax and rotor cables
>(normally four - five if the 2 mtr radio is connected). However, I have to
>admit that more than once I did not disconnect stuff prior to leaving and a
>storm rolled through while I was gone. I can't believe that Drew disconnects
>everything from his K3, PC and router; I can't imagine the amount of time
>that must take having to connect and then re-connect every time it is going
>to storm (I have around 14 or so connected to the K3 - it would take me at
>least 15 minutes to figure out where each one goes!).
>
>Dick K8ZTT
>

TI2/NA7U

Re: Lightning Strike - Metal Roof attracts?

In reply to this post by Alan D. Wilcox, W3DVX

Alan,

Listen to Don Wilhem, he knows of what he speaks. Even if you can't get all that done, get a start on it. I live in Costa Rica and in the "winter" months (June-Nov) it would be unusual if we didn't have a lightning storm nearly every day. If I were you I would at a minimum get that roof grounded at the corners with as big a gauge of bare copper wire that you can. If you get a hit on the roof it will want to travel to ground and you want to guide it there, not let it find its own path, which will likely leave a trail of destruction.

Unplugging stuff is really not the answer. Should lightning travel down that unconnected cable you might get a nice plasma ball out the free end. Keep a fire extinguisher handy.

The Sycom whole house surge suppressor is what we use here and it works great, especially for strikes on the power lines that may be miles away. It takes a surge to ground in 5 ns and connects directly and easily to the main panel. Cost, ... about 50 bux. Little surges like that can damage any equipment in your house right away or gradually over time. You won't even know they are happening until you put one of these suppressors in when you will sometimes notice the lights dim for a fraction of a second as it takes another one to ground.

Good luck!

Casey, TI2/NA7U
http://cloud-warmer.blogspot.com

Cloud Warmer Ham Radio Blog