|
I must first say that I don't have a tower, the trees are higher than my antennas, and we have not so far had a strike on this property since we moved here in 1957, and I have not been struck (stricken?) in my 35 years of Hamming. 57 years of crossed fingers.
However... I have my electrics and radios grounded both to the water pipes, which the electricians and cable techs seem to want to connect, and to the earth itself outside my second floor window. I will likely throw in my MFJ-931 some day to try and halt RF in the shack, but I do not know how to protect from a direct hit, and my Elmer was a radio tech for a local communications specialist, and told horror stories about local commercial installations that were struck (stricken?), and totalled. Of course, most of these were on mountain tops, but it is not just mountain tops that get hit, and many times in the Summer I have heard the "SNAP! - BOOOOOM!!!!!!!) of a really close call here at the home QTH, but no direct hits.
I do unplug all equipment, especially now that it is all solid state and more computer than radio (I look at my modern rigs as computers that transmit RF), and are not as resilient to magnetic disturbances as the old tube rigs I seemed to get in my younger years. Also, living in a house with older wiring from the 1950's (2 wire plugs), I will even pull the power supply plugs if a storm is near, or when leaving the house in the summer.
I wish I had the money to do a complete lightning protection regime for my whole house, but I do not, and have to allocate money, such as, do I want a radio, or lightning protection? Plus, many of us rent, and though it might be safer, many landlords do NOT want all that lightning protection added. Plus, I do not trust "lightning arrestors" much further than I can throw a pig by the tail.
So, I ground everything I can, and remove the coax and antenna wires when it is even threatening a storm. Hope I can make it another 35 years, but then I would be over 100... 73 to the OM's and 88 to the YL's!
KC4BO
On Mon, Jan 6, 2014 at 11:16 AM, <w3ahl@...> wrote:
?
Here are links I've posted previously over the years, consolidated under a relevant subject line for easier searching in the future.
"How to Protect Your Home and Its Contents from Lightning" by IEEE. ?No matter how much your radio system is protected, if the rest of your house is neglected, all is for naught. ?This is very readable. ?Google the title or try: ??
"Lightning Protection & Grounding Solutions for Communication Sites" by Polyphasor. ?Best technical reference. ?Out of print, but Google the title for a downloadable pdf.
"National Electrical Code 2011" has good info in sections 250 on grounding and 800 for communications equipment. ?Easily misinterpreted by all but the best licensed electricians! ?Determine which electrical building codes applies to your area. ?Many counties or states have free downloadable files. ?For the 2011 edition see: ??
A good illustration of Ufer grounding details to supplement NEC (250) is at:
It is always wise to discuss your site's requirements with someone experienced with commercial lightning protection installations or at least several hams (with tall towers that aren't off the air due to lightning damage!). ?It is easy to miss the forest for the trees. ?But it also important to understand the minute details, that aren't obvious to most hams. ?
Ask to see other hams (or better, commercial towers with repeaters) lightning protection installations and ask WHY they did what they did and what they would do differently now.
Steve, W3AHL
|
Many hams have no lightning protection and even more have inadequate protection. ?If you live in an area where the lightning flash density is lower and the attractive profile of your site is less, the odds are in your favor. ?There are "only" about 250,000 homeowner lightning claims filed annually (2008), totaling $1.065 billion.
A map showing annual lightning flash density per square mile is at: ?http://www.vaisala.com/VaisalaImages/Product%20and%20services/NLDN%20CG%20Flash%20Density%20Miles%201997-2010.png
Having trees higher than the antennas offers no protection. ?Trees are attractive objects that increase the probability of a strike. ?A strike within >0.5 miles can damage radios, it doesn't have to be a direct strike. ?Even attic mounted antennas are not immune to damage, as one of our local hams found out last year.
I understand not everyone can justify a whole-house, well-designed lightning protection system. ?I just hate to see experienced hams recommending to others solutions like hanging feed lines 6' away or putting them in glass jars. ?
As far as "not trusting lightning arrestors", there are over 150,000 commercial radio towers in the USA that take lighting strikes every year that rely on Polyphaser, Alpha Delta, etc. suppressors to stay on the air. ? If properly installed, they provide a high probability of protecting equipment. ?The $5 "spark gaps" found at hamfests aren't worth a nickel, however. ?
There are often good deals on ebay for name brand suppressors that are new or pulls from decommissioned sites. ?I bought 20 new Alpha Delta Transi-Taps for less than $10 each including shipping for our local club's fan-dipole antenna party. ?And a group purchase of 650' of #6 copper wire at $0.40/ft. wholesale helped everyone afford proper protection for about $70, depending on how many ground rods they installed. ?We even have electric demo hammers available to help drive the ground rods.
Steve, W3AHL
---In ic7000@..., <anetherton@...> wrote: I must first say that I don't have a tower, the trees are higher than my antennas, and we have not so far had a strike on this property since we moved here in 1957, and I have not been struck (stricken?) in my 35 years of Hamming. 57 years of crossed fingers.
However... I have my electrics and radios grounded both to the water pipes, which the electricians and cable techs seem to want to connect, and to the earth itself outside my second floor window. I will likely throw in my MFJ-931 some day to try and halt RF in the shack, but I do not know how to protect from a direct hit, and my Elmer was a radio tech for a local communications specialist, and told horror stories about local commercial installations that were struck (stricken?), and totalled. Of course, most of these were on mountain tops, but it is not just mountain tops that get hit, and many times in the Summer I have heard the "SNAP! - BOOOOOM!!!!!!!) of a really close call here at the home QTH, but no direct hits.
I do unplug all equipment, especially now that it is all solid state and more computer than radio (I look at my modern rigs as computers that transmit RF), and are not as resilient to magnetic disturbances as the old tube rigs I seemed to get in my younger years. Also, living in a house with older wiring from the 1950's (2 wire plugs), I will even pull the power supply plugs if a storm is near, or when leaving the house in the summer.
I wish I had the money to do a complete lightning protection regime for my whole house, but I do not, and have to allocate money, such as, do I want a radio, or lightning protection? Plus, many of us rent, and though it might be safer, many landlords do NOT want all that lightning protection added. Plus, I do not trust "lightning arrestors" much further than I can throw a pig by the tail.
So, I ground everything I can, and remove the coax and antenna wires when it is even threatening a storm. Hope I can make it another 35 years, but then I would be over 100... 73 to the OM's and 88 to the YL's!
KC4BO
|
All:
I fully agree with Steve, although I do believe there are ways to do
good lightning protection for not much additional money, as long as
the station is planned with that in mind.
I also agree with his recommendation to use good quality arrestors.
One thing though, many hams don't understand that all these things
do (primarily speaking of the coax type protectors) is protect the
input circuits of their radios from impulses induced inside the
transmission line. While they do generally offer a good place to tie
your coax shield to your ground panel (you do have one, right?), you
could do the same by peeling back the outer insulation and
terminating the outer shield to your ground panel. Of course you do
need protectors to save the input to your equipment, but shunting
the common-mode impulse energy to your ground panel is not their
primary purpose and the two functions don't have to be in the same
place. Needless to say, there's more to that discussion.
Chuck - N8DNX
toggle quoted message
Show quoted text
...
I understand not everyone can justify a whole-house, well-designed
lightning protection system. ?I just hate to see experienced hams
recommending to others solutions like hanging feed lines 6' away
or putting them in glass jars.?
...
As
far as "not trusting lightning arrestors", there are over
150,000 commercial radio towers in the USA that take lighting
strikes every year that rely on Polyphaser, Alpha Delta, etc.
suppressors to stay on the air. ? If properly installed, they
provide a high probability of protecting equipment. ?The $5
"spark gaps" found at hamfests aren't worth a nickel, however.?
...
|
Keep in mind also that all the coax surge suppression in the world won't protect you from a surge on your power distribution.?
Mark
Sent from my Verizon Wireless 4G LTE smartphone
|
Okay, Help. ? One antenna 80 meter dipole at 35’ hung from the trees.? Ladder line to the entry point on the house. 1:1 Balun and 10’ of coax to the tuner. When not in use, I unplug my UPS devices from the mains and I unplug the coax from my tuner.? Suggestions on anything else that is needed? ? Now when I AM using the radios I have to UPS devices each rated pretty high for surge to power everything but I have nothing for the antenna as Im not sure what I could do.? Could someone offer an opinion that is simple?? I do not use the radio during thunderstorms or lightning within 15 or 20 miles and I live in a lower area with plenty of object taller than my antenna in the surroundings.? Wish I had a 200ft tower but still waiting for publishers clearinghouse to visit J ? Thank You ? Jon ?
|
Okay, Help.
?
One antenna 80 meter dipole at 35’ hung from the
trees.? Ladder line to the entry point on the house. 1:1 Balun and 10’ of
coax to the tuner.
When not in use, I unplug my UPS devices from the mains and
I unplug the coax from my tuner.? Suggestions on anything else that is
needed?
?
Now when I AM using the radios I have to UPS devices each
rated pretty high for surge to power everything but I have nothing for the
antenna as Im not sure what I could do.? Could someone offer an opinion
that is simple?? I do not use the radio during thunderstorms or lightning
within 15 or 20 miles and I live in a lower area with plenty of object taller
than my antenna in the surroundings.? Wish I had a 200ft tower but still
waiting for publishers clearinghouse to visit J
?
Thank You
?
Jon
?
|
Look at this site,?
Peruse all the products.
JIM
From: Guizar Jon
To: ic7000@...
Sent: Tuesday, January 7, 2014 12:40 PM
Subject: Re: [IC-7000] Lightning Protection References
?
Okay, Help. ? One antenna 80 meter dipole at 35’ hung from the trees.? Ladder line to the entry point on the house. 1:1 Balun and 10’ of coax to the tuner. When not in use, I unplug my UPS devices from the mains and I unplug the coax from my tuner.? Suggestions on anything else that is needed? ? Now when I AM using the radios I have to UPS devices each rated pretty high for surge to power everything but I have nothing for the antenna as Im not sure what I could do.? Could someone offer an opinion that is simple?? I do not use the radio during thunderstorms or lightning within 15 or 20 miles and I live in a lower area with plenty of object
taller than my antenna in the surroundings.? Wish I had a 200ft tower but still waiting for publishers clearinghouse to visit J ? Thank You ? Jon ?
|
Jon,
The problem with unplugging everything is after a while, you tend to forget. ?Unplugging the coax from the tuner protects the radio, at the expense of the house, since even a nearby flash can transfer enough energy through the antenna to jump several feet and ignite objects. ?Plus, after a few hundred mating/unmating cycles, the contact resistance increases and you need to replace the connector in the radio or tuner, although you won't know that until after blaming a dozen other things for the flakey problems....
While the UPS unit is fine for line transients, they are ineffective as a primary defense for most lightning strikes, since the house wiring grounding impedance is too high to dissipate anything but a minor strike. ?A whole-house surge protector mounted at the service panel and grounded to the primary ground via a short #6 or larger ground wire is needed, then the UPS can absorb any let through voltage.
It's hard to make good recommendations without knowing more about your site. ?But to get started with a simple plan:
1. ?An unprotected feed line should never enter a dwelling. ?You need a lightning suppressor mounted on or connected to, an 8' ground rod. ?For just one lightning suppressor, you can take an Alpha Delta TT3G50 and screw its 1/4" threaded stud into a ground rod clamp instead of its wire clamping screw. ?That give you the lowest possible impedance to ground and simplifies mounting. ?Most hams have more antennas eventually, so then a ground bus bar is needed. ?See the photo at: ?http://www.alphadeltacom.com/ ? for an example.
I prefer Polyphaser suppressors, except for how they mount. ?I modify them to accept a larger bolt. ?I also use a stainless steel shim between the copper bus bar and aluminum suppressor, to prevent galvanic corrosion. ?
2. ?Run the antenna coax to the suppressor, then use another jumper from the suppressor to inside the house. ?Do not attach the unprotected coax to the house directly. ?You can tie it off with at least 2' of dacron or nylon rope if needed, to prevent arc-over to the house. ?Waterproof the coax connectors and the arc plug that screws into the top of the suppressor (even though they say it's waterproof). ?I use butyl self-fusing tape, applied over a layer of electrical tape (so you can remove the connector someday), with another layer of tape over the butyl to protect it from UV. ?There are other good ways, but just electrical tape isn't one of them.
3. ?The National Electric Code requires all secondary grounding connections to be connected to the primary electrical panel ground rod with at least #6 copper wire, using approved ground rod clamps (or other approved methods). ?This wire should be buried, if possible, about 6" below the surface. ?This protects it and greatly improves its ability to shunt current to the earth. ?You can buy 5/8" x 8' ground rods, clamps and wire at Home Depot, Lowes, etc. ?You do not usually need to be a licensed electrician or need a permit to install a simple ground wire, as long as you aren't modifying the primary ground rod or wiring to the electrical panel.
Ground wires used for lightning protection (as opposed to fault current safety) must never have sharp bends. ?Use at least a 6" radius bend. ?If attached to a structure, they must be secured every 3 feet (varies depending on local code, size of wire, etc.) to prevent the magnetic force of the current from a direct strike from ripping the wire off the building and severing the wire.
4. ?The ground rod clamp comes in several varieties. ?You don't want the $2 one. ?Get one rated for DIRECT BURIAL, as stated on the printed label attached to it. ?It will cost about $4.50. ?Don't use one that just squeezes the wire between the clamp and the rod. ?Get the split clamp with two bolts that hold the clamp together and a third screw to secure the copper wire. ?This third screw is the one you would replace with the stud of the TT3G50 suppressor, if you chose to go that route. ?Tighten all screws really tight. ?Then tighten them a little more. ?
5. ?A fence post driver is MUCH easier to drive rods than a sledge hammer. ?Ask around -- some ham will have one. ?They cost about $30-40.
6. ?If your soil is very rocky or there is hard pan a couple of feet below the surface, you need to consider different approaches, but I won't go into those for now. ?
7. ?I never use just one ground rod, even for a simple dipole. ?Add at least one more 16' away from the first, preferably along the run of wire to the electrical panel. ?If you live in a high flash density area like Florida, even more are worthwhile.
8. ?I personally don't unplug my feed lines from the radios usually, UNLESS I know a thunderstorm is likely or if I'm away from the house for days. ?When I unplug the coax inside, I plug them into shorting plugs mounted on the 2" wide copper strap that runs the length of my bench that is used for equipment grounds. ?This prevents any sparks from jumping around inside. ?A coax switch that grounds unused positions and the radio when the knob is in the OFF position is another option. ?Alpha Delta makes those also, although I haven't used them personally.
9. ?It is good to run a #6 copper ground wire (I use stranded, insulated wire usually here) from the lightning suppressor ground to the operating position. ?This serves as your single-point RF ground for the radio, tuner, computer, etc. ?Your radio and tuner usually have a designated grounding screw. ?Connect each unit to the ground wire from outside. ?Don't connect the radio ground, to the tuner ground to the computer ground then to the main ground wire going outside. ?Each unit has its own wire to the main ground. ?Many use a copper ground bus to attach the various unit grounds to. ?I use #6 or #8 insulated, stranded wire with ring lugs for runs to the units. ?Keep them short. ?Don't bother using flat braid, regular wire is just as good here.
10. ?Consider having an electrician install a whole-house surge protector if lightning damage is common in your area and you own the house. ?There are suppressors that replace an existing circuit breaker, which could be installed in a rental, but they would be a distant second choice, but better than a UPS. ?Otherwise, just leave your UPS plugged in. ?If lightning comes in on the utility line, your radio will be the least of your problems.
Feel free to ask questions or clarify details. ?Seldom are installations as simple as I assumed above.
Steve, W3AHL
---In ic7000@..., <jon@...> wrote: Okay, Help. ? One antenna 80 meter dipole at 35’ hung from the trees.? Ladder line to the entry point on the house. 1:1 Balun and 10’ of coax to the tuner. When not in use, I unplug my UPS devices from the mains and I unplug the coax from my tuner.? Suggestions on anything else that is needed? ? Now when I AM using the radios I have to UPS devices each rated pretty high for surge to power everything but I have nothing for the antenna as Im not sure what I could do.? Could someone offer an opinion that is simple?? I do not use the radio during thunderstorms or lightning within 15 or 20 miles and I live in a lower area with plenty of object taller than my antenna in the surroundings.? Wish I had a 200ft tower but still waiting for publishers clearinghouse to visit J ? Thank You ? Jon ?
|
Thank You Steve, ? I appreciate the information.? Local hams here are suggesting I get rid of my coax section and run the window line all the way to the tuner (for performance not for protection).? Is there a way to protect the gear when fed with only window line? ? Jon - K3JEG
|
All:
Jon did a good job listing individual items related to lightning protection for a station. I think what's missing here though is a philosophy and strategy.
I see the philosophy as "Dissipate energy where it can do no harm and isolate and protect things that can be harmed". I also see the strategy as the following.
* Encourage dissipation of a lightning discharge into the ground outside of your house
* Discourage energy transfer to your house
* Deal with energy that will transfer to your station in a way that it will cause no harm
* Minimize transfer of energy to the rest of the house
If you don't have a philosophy and don't follow a strategy, you're only randomly throwing things and money at the problem and potentially endangering your equipment, your home, and yourself. Unfortunately, I don't don't see much of this prior thought with Hams, and perhaps not enough in the commercial world either. I also often hear things that are seriously misguided, such as disconnecting cables without thought to what those cable ends represent in a strike. Knowing what you need to accomplish and having an approach to define your implementation would seem to be a necessary first step. With that in hand, the particulars should start to fall in place.
Frankly, I see this as a failing of Ham Radio in general. Even many of the Web sites and published articles on this subject seem lacking. Perhaps this is one negative artifact of the Elmer system.
Chuck - N8DNX
|
de WB2CPN
Been in USAF communications and Ham Radio since 1946,
and some were large antenna farms.
Rule, (and exceptions): Everything coming into the house should
have an easy way to be disconnected from everything. The
disconnect is best done outside the house. And it must grounded
to prevent a static charge buildup. The lightning ions will have one
polarity, the thing on the ground will aquire the opposite polarity, so
they sit there for a while teasing each other. But not for long. Then, Zap!
As Chuck says, there's more to "Grounding" than meets the eye.
We are not talking a DC Ground, like with an Ohmmeter, but a
Lighting Ground which can deal with a high-current, short-period
impulse that can be induced by the field of a near-by lighting flash.
It's entertaining to watch the hits on the 75-foot poles of a well
populated HF antenna field, and to watch the arcs on the spark
gaps where the open wire transmission lines come into the
transmitter building, but the not-so-funny part is when a table-top
radio in the living room, plugged into the AC plug, got zapped.
Then, recently my IC-7000, which was not disconnected, got zapped.
It was totaled, the main board was really whacked. Strange, but
that radio used a long-wire antenna, and had an AH-4 Tuner at
the well head about 40 feet from the house. A close analysis of
the destroyed board was that the lightning pulse came in on the
AH-4 control cable, not on the coax. Very Strange.
73 Clete
================================================
toggle quoted message
Show quoted text
On 1/8/2014 10:24 AM, Charles Scott wrote:
All:
Jon did a good job listing individual items related to lightning
protection for a station. I think what's missing here though is a
philosophy and strategy.
I see the philosophy as "Dissipate energy where it can do no harm and
isolate and protect things that can be harmed". I also see the strategy
as the following.
* Encourage dissipation of a lightning discharge into the ground outside
of your house
* Discourage energy transfer to your house
* Deal with energy that will transfer to your station in a way that it
will cause no harm
* Minimize transfer of energy to the rest of the house
If you don't have a philosophy and don't follow a strategy, you're only
randomly throwing things and money at the problem and potentially
endangering your equipment, your home, and yourself. Unfortunately, I
don't don't see much of this prior thought with Hams, and perhaps not
enough in the commercial world either. I also often hear things that are
seriously misguided, such as disconnecting cables without thought to
what those cable ends represent in a strike. Knowing what you need to
accomplish and having an approach to define your implementation would
seem to be a necessary first step. With that in hand, the particulars
should start to fall in place.
Frankly, I see this as a failing of Ham Radio in general. Even many of
the Web sites and published articles on this subject seem lacking.
Perhaps this is one negative artifact of the Elmer system.
Chuck - N8DNX
|
Clete:
Yep, textbook examples of letting what energy gets to your radio result in current through it.
Not so strange about the damage from the AH-4 control line. Need to treat that just as you would the transmission line. Most damage is not done by what comes down the inside of the transmission line but rather what comes down the outside of the transmission line and on control lines ("common-mode").
In both cases, you got your radio between the source of the energy (lightning strike on your antenna) and a place for it to go (AC outlet).
The point here is that you can have voltage from a strike reach your equipment as long as there's no where for the current to go. If you had the equipment hanging off a common grounding panel through which you brought all the lines (transmission line, control lines, power lines), there were protectors for all of them, and there was no other path for current (i.e. radio->desk->cement floor), the radio would have been fine.
This is what "Single Point Grounds" are all about. Not a complete solution, but a key part of it.
Chuck - N8DNX
toggle quoted message
Show quoted text
On 1/8/2014 3:13 PM, C.Whitaker wrote: ... but the not-so-funny part is when a table-top
radio in the living room, plugged into the AC plug, got zapped.
Then, recently my IC-7000, which was not disconnected, got zapped.
It was totaled, the main board was really whacked. Strange, but
that radio used a long-wire antenna, and had an AH-4 Tuner at
the well head about 40 feet from the house. A close analysis of
the destroyed board was that the lightning pulse came in on the
AH-4 control cable, not on the coax. Very Strange.
|
I live in a low density hit area in central Maine during the summer and I am surprised that it is low according to the chart posted above. My area is a lightning belt and we have some wicked and frequent lightning storms. I have a boxful of cordless phones, computer modems, surge protectors and other "stuff" to prove that a direct hit is not necessary to destroy electronics and that unplugging everything is not the answer. This is one of the ?most important threads on this site IMHO and clearly emphasizes the importance of grounding against lightning as it is capricious and completely unpredictable. It is too easy to say, " Oh well the storm is not here but 20 miles away. No worries," Thank you all for your knowledge and insights into this most important issue. I winter in NYC
and don't think I have to worry because I am in a 4 story building surrounded by giants but now I am not too sure that I shouldn't do something. I sure am going to have a plan implemented when I return to Maine and will use this thread as a place to start. On Wednesday, January 8, 2014 3:13 PM, C.Whitaker wrote:
?
de WB2CPN
Been in USAF communications and Ham Radio since 1946,
and some were large antenna farms.
Rule, (and exceptions): Everything coming into the house should
have an easy way to be disconnected from everything. The
disconnect is best done outside the house. And it must grounded
to prevent a static charge buildup. The lightning ions will have one
polarity, the thing on the ground will aquire the opposite polarity, so
they sit there for a while teasing each other. But not for long. Then, Zap!
As Chuck says, there's more to "Grounding" than meets the eye.
We are not talking a DC Ground, like with an Ohmmeter, but a
Lighting Ground which can deal with a high-current, short-period
impulse that can be induced by the field of a near-by lighting flash.
It's entertaining to watch the hits on the 75-foot poles of a well
populated HF antenna field, and to watch the arcs on the spark
gaps where the open wire transmission lines come into the
transmitter building, but the not-so-funny part is when a table-top
radio in the living room, plugged into the AC plug, got zapped.
Then, recently my IC-7000, which was not disconnected, got zapped.
It was totaled, the main board was really whacked. Strange, but
that radio used a long-wire antenna, and had an AH-4 Tuner at
the well head about 40 feet from the house. A close analysis of
the destroyed board was that the lightning pulse came in on the
AH-4 control cable, not on the coax. Very Strange.
73 Clete
================================================
On 1/8/2014 10:24 AM, Charles Scott wrote:
>
>
> All:
>
> Jon did a good job listing individual items related to lightning
> protection for a station. I think what's missing here though is a
> philosophy and strategy.
>
> I see the philosophy as "Dissipate energy where it can do no harm and
> isolate and protect things that can be harmed". I also see the strategy
> as the following.
>
> * Encourage dissipation of a lightning discharge into the ground outside
> of your house
> * Discourage energy transfer to your house
> * Deal with energy that will transfer to your station in a way that it
> will cause no harm
> * Minimize transfer of energy to the rest of the house
>
> If you don't have a philosophy and don't follow a strategy, you're only
> randomly throwing things and money at the problem and potentially
> endangering your equipment, your home, and yourself. Unfortunately, I
> don't don't see much of this prior thought with Hams, and perhaps not
> enough in the commercial world either. I also often hear things that are
> seriously misguided, such as disconnecting cables without thought to
> what those cable ends represent in a strike. Knowing what you need to
> accomplish and having an approach to define your implementation would
> seem to be a necessary first step. With that in hand, the particulars
> should start to fall in place.
>
> Frankly, I see this as a failing of Ham Radio in general. Even many of
> the Web sites and published articles on this subject seem lacking.
> Perhaps this is one negative artifact of the Elmer system.
>
> Chuck - N8DNX
>
>
|
Is there a way to make or build a grounding system to attach the antennas into when leaving the rig(s) in lightning season? Like, make a ground wire with SO-239's and banana type plugs, and plug all antennae into it?
TNX de KC4BO
On Wed, Jan 8, 2014 at 3:13 PM, C.Whitaker <whitaker@...> wrote:
?
de WB2CPN
Been in USAF communications and Ham Radio since 1946,
and some were large antenna farms.
Rule, (and exceptions): Everything coming into the house should
have an easy way to be disconnected from everything. The
disconnect is best done outside the house. And it must grounded
to prevent a static charge buildup. The lightning ions will have one
polarity, the thing on the ground will aquire the opposite polarity, so
they sit there for a while teasing each other. But not for long. Then, Zap!
As Chuck says, there's more to "Grounding" than meets the eye.
We are not talking a DC Ground, like with an Ohmmeter, but a
Lighting Ground which can deal with a high-current, short-period
impulse that can be induced by the field of a near-by lighting flash.
It's entertaining to watch the hits on the 75-foot poles of a well
populated HF antenna field, and to watch the arcs on the spark
gaps where the open wire transmission lines come into the
transmitter building, but the not-so-funny part is when a table-top
radio in the living room, plugged into the AC plug, got zapped.
Then, recently my IC-7000, which was not disconnected, got zapped.
It was totaled, the main board was really whacked. Strange, but
that radio used a long-wire antenna, and had an AH-4 Tuner at
the well head about 40 feet from the house. A close analysis of
the destroyed board was that the lightning pulse came in on the
AH-4 control cable, not on the coax. Very Strange.
73 Clete
================================================
On 1/8/2014 10:24 AM, Charles Scott wrote:
>
>
> All:
>
> Jon did a good job listing individual items related to lightning
> protection for a station. I think what's missing here though is a
> philosophy and strategy.
>
> I see the philosophy as "Dissipate energy where it can do no harm and
> isolate and protect things that can be harmed". I also see the strategy
> as the following.
>
> * Encourage dissipation of a lightning discharge into the ground outside
> of your house
> * Discourage energy transfer to your house
> * Deal with energy that will transfer to your station in a way that it
> will cause no harm
> * Minimize transfer of energy to the rest of the house
>
> If you don't have a philosophy and don't follow a strategy, you're only
> randomly throwing things and money at the problem and potentially
> endangering your equipment, your home, and yourself. Unfortunately, I
> don't don't see much of this prior thought with Hams, and perhaps not
> enough in the commercial world either. I also often hear things that are
> seriously misguided, such as disconnecting cables without thought to
> what those cable ends represent in a strike. Knowing what you need to
> accomplish and having an approach to define your implementation would
> seem to be a necessary first step. With that in hand, the particulars
> should start to fall in place.
>
> Frankly, I see this as a failing of Ham Radio in general. Even many of
> the Web sites and published articles on this subject seem lacking.
> Perhaps this is one negative artifact of the Elmer system.
>
> Chuck - N8DNX
>
>
|
For my shorting plugs I use 2" x 0.06" copper strap with SO-239 chassis receptacles mounted on it. ?Drill a hole just large enough for the center pin on the back and also for the mounting ears. ?Screw the receptacles in place, solder the center pins to the copper and connect a heavy ground wire to the copper. ?In my case the 2" copper strap is tied to the ground bus bar in the entry box outside and is routed inside and across the back of the operating bench. ?But it is important still to have exterior lightning protection before the cables enter the house.
If you disconnect and ground outside, you need to weatherproof the connectors.
Steve, W3AHL ---In ic7000@..., <anetherton@...> wrote: Is there a way to make or build a grounding system to attach the antennas into when leaving the rig(s) in lightning season? Like, make a ground wire with SO-239's and banana type plugs, and plug all antennae into it?
TNX de KC4BO
|
Chuck,
I disagree that most of the lightning energy flows down the outside of the coax shield. ?If a dipole antenna is in the discharge field of a flash, both elements will receive similar coupled charges and that energy will flow down the coax just as any EM field would. ?While lightning is often described as a DC event, the microsecond rise times and the immediate return stroke makes it behave as RF. ?Even if the field potential is uniform across the dipole's length, the center conductor would carry as much energy as the shield toward earth.
But I agree with the rest. ?Most homes can't easily and implement the classic single point ground you described (which is the best approach). ?That's why the NEC requires all earth grounding points (rods, pipes, structural steel, Ufer encased grounds, etc.) to be bonded together at the primary electrical entrance panel (typically).
Without bonding the radio entry panel ground to the electrical entrance panel ground, the radio grounds may rise to thousands of volts due to the I*R drop of the grounding system, while the AC outlet grounds are still at a low potential (but not for long!) ?This is the most common problem that I've seen at ham stations -- not bonding all grounds together. ?There is a misconception that doing so will let the lightning into the house wiring, when just the opposite is the case. ? Thus the common misconception that you can't stop lightning damage, even with good grounding and lightning suppressors at the shack. ?
It's true can't fight lightning, you have to let things "float" along with it while the energy is dissipated rapidly and harmlessly into the earth.
Steve, W3AHL ---In ic7000@..., <cscott@...> wrote: Clete:
Yep, textbook examples of letting what energy gets to your radio result
in current through it.
Not so strange about the damage from the AH-4 control line. Need to
treat that just as you would the transmission line. Most damage is not
done by what comes down the inside of the transmission line but rather
what comes down the outside of the transmission line and on control
lines ("common-mode").
In both cases, you got your radio between the source of the energy
(lightning strike on your antenna) and a place for it to go (AC outlet).
The point here is that you can have voltage from a strike reach your
equipment as long as there's no where for the current to go. If you had
the equipment hanging off a common grounding panel through which you
brought all the lines (transmission line, control lines, power lines),
there were protectors for all of them, and there was no other path for
current (i.e. radio->desk->cement floor), the radio would have been fine.
This is what "Single Point Grounds" are all about. Not a complete
solution, but a key part of it.
Chuck - N8DNX
On 1/8/2014 3:13 PM, C.Whitaker wrote:
> ... but the not-so-funny part is when a table-top
> radio in the living room, plugged into the AC plug, got zapped.
> Then, recently my IC-7000, which was not disconnected, got zapped.
> It was totaled, the main board was really whacked. Strange, but
> that radio used a long-wire antenna, and had an AH-4 Tuner at
> the well head about 40 feet from the house. A close analysis of
> the destroyed board was that the lightning pulse came in on the
> AH-4 control cable, not on the coax. Very Strange.
>
|
My shack in Maine is a wood outbuilding and the inside fuse box is about 10 feet from my equipment. Just on the other side ?of the wall is the outside meter and there is a heavy braided wire buried into earth ground. When I first set up my shack in September I had the power company come out to check the system for good grounding and it passed.?
1.
Should I use their braided ground wire in my ground system? 2. What would be the best way to hook up if I can? Should I set up something inside to hook everything up to or outside? 3. Does bonding all ground wires mean that they need to be actually soldered together or just connected to a common ground bar individually?
Thanks
bb KC1AKV.
On Wednesday, January 8, 2014 7:59 PM, "w3ahl@..." wrote:
?
Chuck,
I disagree that most of the lightning energy flows down the outside of the coax shield. ?If a dipole antenna is in the discharge field of a flash, both elements will receive similar coupled charges and that energy will flow down the coax just as any EM field would. ?While lightning is often described as a DC event, the microsecond rise times and the immediate return stroke makes it behave as RF. ?Even if the field potential is uniform across the dipole's length, the center conductor would carry as much energy as the shield toward earth.
But I agree with the rest. ?Most homes can't easily and implement the classic single point ground you described (which is the best approach). ?That's why the NEC requires all earth grounding points (rods, pipes, structural steel, Ufer encased grounds, etc.) to be bonded together at the primary electrical entrance panel (typically).
Without
bonding the radio entry panel ground to the electrical entrance panel ground, the radio grounds may rise to thousands of volts due to the I*R drop of the grounding system, while the AC outlet grounds are still at a low potential (but not for long!) ?This is the most common problem that I've seen at ham stations -- not bonding all grounds together. ?There is a misconception that doing so will let the lightning into the house wiring, when just the opposite is the case. ? Thus the common misconception that you can't stop lightning damage, even with good grounding and lightning suppressors at the shack. ?
It's
true can't fight lightning, you have to let things "float" along with it while the energy is dissipated rapidly and harmlessly into the earth.
Steve, W3AHL ---In ic7000@..., wrote: Clete:
Yep, textbook examples of letting what energy gets to your radio result
in current through it.
Not so strange about the damage from the AH-4 control line. Need to
treat that just as you would the transmission line. Most damage is not
done by what comes down the inside of the transmission line but rather
what comes down the outside of the transmission line and on control
lines ("common-mode").
In both cases, you got your radio between the source of the energy
(lightning strike on your antenna) and a place for it to go (AC outlet).
The point here is that you can have voltage from a strike reach your
equipment as long as there's no where for the current to go. If you had
the equipment hanging off a common grounding panel through which you
brought all the lines (transmission line, control lines, power lines),
there were protectors for all of them, and there was no other path for
current (i.e. radio->desk->cement floor), the radio would have been fine.
This is what "Single Point Grounds" are all about. Not a complete
solution, but a key part of it.
Chuck - N8DNX
On 1/8/2014 3:13 PM, C.Whitaker wrote:
> ... but the not-so-funny part is when a table-top
> radio in the living room, plugged into the AC plug, got zapped.
> Then, recently my IC-7000, which was not disconnected, got zapped.
> It was totaled, the main board was really whacked. Strange, but
> that radio used a long-wire antenna, and had an AH-4 Tuner at
> the well head about 40 feet from the house. A close analysis of
> the destroyed board was that the lightning pulse came in on the
> AH-4 control cable, not on the coax. Very Strange.
>
|
Bob,
My comments are embedded below. ?In the past, this group's moderator has suggested that long threads not directly related to the IC-7000, be taken off list or pursued on a more appropriate reflector. ?A good source of info for all things related to grounding of radio systems, antenna installations, etc. is the towertalk reflector at: ?http://lists.contesting.com/mailman/listinfo/towertalk ?. ?Searchable archives are at: ?http://lists.contesting.com/_towertalk/ ?. ?Many discussions go on for weeks, but there are some real pro's there (along with some not so knowledgeable of course).
Steve, W3AHL
---In ic7000@..., <bobbrooks220@...> wrote: My shack in Maine is a wood outbuilding and the inside fuse box is about 10 feet from my equipment. Just on the other side ?of the wall is the outside meter and there is a heavy braided wire buried into earth ground. When I first set up my shack in September I had the power company come out to check the system for good grounding and it passed.?
[W3AHL] ?When utility companies and electricians check the electrical service grounding, they usually are only verifying that it meets local building code / NEC requirements, which are primarily for fault current protection in residential buildings. ?Seldom are they concerned with lightning & RF grounding.
1.
Should I use their braided ground wire in my ground system?
[W3AHL] I don't have enough info to give you a good answer. ?I assume you plan to add more ground rods near the shack for lightning suppressors. ?Additional ground rods should be bonded to another ground rod, which eventually is bonded to the primary electrical ground rod. ?You should not bond a ground rod to a wire that goes to another ground rod. ? And you should have the new "radio" grounding tied to your shack's fuse box ground using as direct a path as possible. ?If the braided wire goes to a nearby ground rod and then to the house electrical panel, you should tie your new rods to that rod. ?If the braided wire is buried all the way to the house with no ground rod connection near the shack, then you should consult an electrician. ?Bonding the existing buried braided wire to a new ground rod? may require a special clamp to ensure a reliable, long term, low resistance connection. ?
2. What would be the best way to hook up if I can? Should I set up something inside to hook everything up to or outside?
[W3AHL] ?All of your additional grounding and lightning protection should be outside of the shack, when possible. ?If done correctly, it is OK to have the lightning suppressors inside the shack. ?Many commercial towers' comm's shelter are that way, but they are concrete, aren't a dwelling and have over-engineered grounding systems designed for worst-case hits usually. ?I would suggest getting a weatherproof metal enclosure to run your feed line into and to house the lightning suppressors. ?Mount it no more than 18" above ground level, so your grounding wires will have a short path to the first ground rod. ?If you mount the box inside at the same location, that would be OK usually, but there are more details to address if you want it done correctly....?
3. Does bonding all ground wires mean that they need to be actually soldered together or just connected to a common ground bar individually?
[W3AHL] ?I'm not sure which ground wire you are referring to here. ?If it is the wires bonding ground rods together, they must attach to another ground rod using an approved clamp or other method. ?Connections for lightning protection or primary grounds are NEVER soldered.
If you're referring to the wires connecting each piece of equipment in the shack, either way is acceptable I guess. ?But I would use crimp ring terminals (with the correct crimper tool) to a small copper bus bar. ?I use a 10-ton hydraulic crimper for #6 and larger. ?Light duty units are available for about $60 on ebay. ?Flat copper strap is a good way to connect your RF grounds from radios to your ground bus where the lightning suppressors are mounted. ?I have also used it for the lightning suppressor bus bar, although I usually make it double thickness. ?1.5" x 0.25" copper bar is better mechanically and is readily available from commercial radio installers or on ebay (from decommissioned tower sites). ?Don't use aluminum, since the surface oxide is an insulator and copper will corrode if connected directly to aluminum. ?Both issues can be addressed, but I would avoid it.
One additional issue: ?If your soil is very rocky (not loam or sandy clay) then you may need something other than ground rods to achieve a low impedance path to earth.
Thanks
bb KC1AKV. ..snip..
|
OK Got it Steve and thanks for being so kind as to answer my questions.
bb KC1AKV
On Thursday, January 9, 2014 10:21 AM, "w3ahl@..." <w3ahl@...> wrote:
?
Bob,
My comments are embedded below. ?In the past, this group's moderator has suggested that long threads not directly related to the IC-7000, be taken off list or pursued on a more appropriate reflector. ?A good source of info for all things related to grounding of radio systems, antenna installations, etc. is the towertalk reflector at: ?http://lists.contesting.com/mailman/listinfo/towertalk ?. ?Searchable archives are at: ?http://lists.contesting.com/_towertalk/ ?. ?Many discussions go on for weeks, but there are some real pro's there (along with some not so knowledgeable of course).
Steve, W3AHL
---In ic7000@..., wrote: My shack in Maine is a wood outbuilding and the inside fuse box is about 10 feet from my equipment. Just on the other side ?of the wall is the outside meter and there is a heavy braided wire buried into earth ground. When I first set up my shack in September I had the power company come out to check the system for good grounding and it passed.?
[W3AHL] ?When utility companies and electricians check the electrical service grounding, they usually are only verifying that it meets local building code / NEC requirements, which are primarily for fault current protection in residential buildings. ?Seldom are they concerned with lightning &
RF grounding.
1.
Should I use their braided ground wire in my ground system?
[W3AHL] I don't have enough info to give you a good answer. ?I assume you plan to add more ground rods near the shack for lightning suppressors. ?Additional ground rods should be bonded to another ground rod, which eventually is bonded to the primary electrical ground rod. ?You should not bond a ground rod to a wire that goes to another ground rod.
? And you should have the new "radio" grounding tied to your shack's fuse box ground using as direct a path as possible. ?If the braided wire goes to a nearby ground rod and then to the house electrical panel, you should tie your new rods to that rod. ?If the braided wire is buried all the way to the house with no ground rod connection near the shack, then you should consult an electrician. ?Bonding the existing buried braided wire to a new ground rod? may require a special clamp to ensure a reliable, long term, low resistance connection. ?
2. What would be the best way to hook up if I can? Should I set up something inside to hook everything up to or outside?
[W3AHL] ?All of your additional grounding and lightning protection should be outside of the shack, when possible. ?If done correctly, it is OK to have the lightning suppressors inside the shack. ?Many commercial towers' comm's shelter are that way, but they are concrete, aren't a dwelling and have over-engineered grounding systems designed for worst-case hits usually. ?I would suggest getting a weatherproof metal enclosure to run your feed line into and to house the lightning suppressors. ?Mount it no more than 18" above ground level, so your grounding wires will have a short path to the first ground rod. ?If you mount the box inside at the same location, that would be OK usually, but there are more details to address if you want it done correctly....?
3. Does bonding all ground wires mean that they need to be actually soldered together or just connected to a common ground bar individually?
[W3AHL] ?I'm not sure which ground wire you are referring to here. ?If it is the wires bonding ground rods together, they must attach to another ground rod using an approved clamp or other method. ?Connections for lightning protection or primary grounds are NEVER soldered.
If you're referring to the wires connecting each piece of equipment in the shack, either way is acceptable I guess. ?But I would use crimp ring terminals (with the correct crimper tool) to a small copper bus bar. ?I use a 10-ton hydraulic crimper for #6 and larger. ?Light duty units are available for about $60 on ebay. ?Flat copper strap is a good way to connect your RF grounds from radios to your ground bus where the lightning suppressors are mounted. ?I have also used it for the lightning suppressor bus bar, although I usually make it double thickness. ?1.5" x 0.25" copper bar is better mechanically and is readily available from commercial radio installers or on ebay (from decommissioned tower sites). ?Don't use aluminum, since the surface oxide is an insulator and copper will corrode if connected
directly to aluminum. ?Both issues can be addressed, but I would avoid it.
One additional issue: ?If your soil is very rocky (not loam or sandy clay) then you may need something other than ground rods to achieve a low impedance path to earth.
Thanks
bb KC1AKV. ..snip..
|
My ground is setup where all the gear goes to a grounding strip to a single
8 foot ground round, and then the antenna is grounded to a separate 8 foot
ground rod (via) a lightning arrester
Brian Mackey
KC1MAC/AG
Hams don't let hams get stuck on 2 meter repeaters!
From: <w3ahl@...>
Reply-To: <ic7000@...>
Date: Thursday, January 9, 2014 at 10:21 AM
To: <ic7000@...>
Subject: Re: [IC-7000] Lightning Protection References
Bob,
My comments are embedded below. In the past, this group's moderator has
suggested that long threads not directly related to the IC-7000, be taken
off list or pursued on a more appropriate reflector. A good source of info
for all things related to grounding of radio systems, antenna installations,
etc. is the towertalk reflector at:
. Searchable
archives are at: . Many
discussions go on for weeks, but there are some real pro's there (along with
some not so knowledgeable of course).
Steve, W3AHL
---In ic7000@..., <bobbrooks220@...> wrote:
My shack in Maine is a wood outbuilding and the inside fuse box is about 10
feet from my equipment. Just on the other side of the wall is the outside
meter and there is a heavy braided wire buried into earth ground. When I
first set up my shack in September I had the power company come out to check
the system for good grounding and it passed.
[W3AHL] When utility companies and electricians check the electrical
service grounding, they usually are only verifying that it meets local
building code / NEC requirements, which are primarily for fault current
protection in residential buildings. Seldom are they concerned with
lightning & RF grounding.
1. Should I use their braided ground wire in my ground system?
[W3AHL] I don't have enough info to give you a good answer. I assume you
plan to add more ground rods near the shack for lightning suppressors.
Additional ground rods should be bonded to another ground rod, which
eventually is bonded to the primary electrical ground rod. You should not
bond a ground rod to a wire that goes to another ground rod. And you
should have the new "radio" grounding tied to your shack's fuse box ground
using as direct a path as possible. If the braided wire goes to a nearby
ground rod and then to the house electrical panel, you should tie your new
rods to that rod. If the braided wire is buried all the way to the house
with no ground rod connection near the shack, then you should consult an
electrician. Bonding the existing buried braided wire to a new ground rod
may require a special clamp to ensure a reliable, long term, low resistance
connection.
2. What would be the best way to hook up if I can? Should I set up something
inside to hook everything up to or outside?
[W3AHL] All of your additional grounding and lightning protection should be
outside of the shack, when possible. If done correctly, it is OK to have
the lightning suppressors inside the shack. Many commercial towers' comm's
shelter are that way, but they are concrete, aren't a dwelling and have
over-engineered grounding systems designed for worst-case hits usually. I
would suggest getting a weatherproof metal enclosure to run your feed line
into and to house the lightning suppressors. Mount it no more than 18"
above ground level, so your grounding wires will have a short path to the
first ground rod. If you mount the box inside at the same location, that
would be OK usually, but there are more details to address if you want it
done correctly....
3. Does bonding all ground wires mean that they need to be actually soldered
together or just connected to a common ground bar individually?
[W3AHL] I'm not sure which ground wire you are referring to here. If it is
the wires bonding ground rods together, they must attach to another ground
rod using an approved clamp or other method. Connections for lightning
protection or primary grounds are NEVER soldered.
If you're referring to the wires connecting each piece of equipment in the
shack, either way is acceptable I guess. But I would use crimp ring
terminals (with the correct crimper tool) to a small copper bus bar. I use
a 10-ton hydraulic crimper for #6 and larger. Light duty units are
available for about $60 on ebay. Flat copper strap is a good way to connect
your RF grounds from radios to your ground bus where the lightning
suppressors are mounted. I have also used it for the lightning suppressor
bus bar, although I usually make it double thickness. 1.5" x 0.25" copper
bar is better mechanically and is readily available from commercial radio
installers or on ebay (from decommissioned tower sites). Don't use
aluminum, since the surface oxide is an insulator and copper will corrode if
connected directly to aluminum. Both issues can be addressed, but I would
avoid it.
One additional issue: If your soil is very rocky (not loam or sandy clay)
then you may need something other than ground rods to achieve a low
impedance path to earth.
Thanks
bb
KC1AKV.
..snip..
[Non-text portions of this message have been removed]
|
Steve W3AHL