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Author Topic: Country home prone to lightning strikes - looking for input on other things too  (Read 3561 times)
HAPLO
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« Reply #15 on: July 13, 2011, 11:36:56 AM »

Consider a rig like the Kenwood TS 2000, Which is the true "jack of all trades, Do it all" radio. Selling good used nowadays as low as 900 bucks, And brand new for less than 1500.  (The TS2000 is actually TWO radios in one box, Capable of monitoring HF and VHF at the same time, Plus cross band repeat between HF, VHF, And UHF!  A really neat feature that none of the little "DC to daylight" mobil rigs can do.

I fully expect to move whatever radio I end up with initially to my truck in the future, so a non-mobile radio probably won't be my first purchase.

I am aware that 10m and 6m will not be something used initially, regardless of SSB or FM - simply for the fact that as others have pointed out, my area is alive and well with 2m, AND I don't want to bite off more than I can chew at first. I'm looking forward to playing with a simple ground plane antenna for my first rig; I'd like to keep things simple at first so I don't overwhelm my expectations. Smiley

I read another post somewhere about testing the ohms in a ground rod, and how to tell if the ground rod was sufficiently deep, and not corroded somewhere below the surface. How do you test a ground rod's resistance? I assume dealing with the earth, it takes a little more than simply hooking up a simple digital multimeter to it.

Thanks all,
H.

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W8JI
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« Reply #16 on: July 14, 2011, 06:29:27 AM »

I read another post somewhere about testing the ohms in a ground rod, and how to tell if the ground rod was sufficiently deep, and not corroded somewhere below the surface. How do you test a ground rod's resistance? I assume dealing with the earth, it takes a little more than simply hooking up a simple digital multimeter to it.

IMO that is one of the most meaningless things to do, except to see if you have a good power line safety ground.

I can have a ground system that measures near zero ohms at DC or 60 Hz in a measurement, and it can be a horrible totally useless ground for lightning. On the other hand a ground that measures much higher resistance than that one could be hundreds of times more effective.

The thing to do is install the system properly. Then you don't need to waste time making measurements that don't really tell you anything that is dependable.

73 Tom
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W0BTU
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« Reply #17 on: July 14, 2011, 12:20:23 PM »

I get hit all the time here. I have a 318 ft tower and a bunch of other towers that are the tallest things for miles, and I am on a slight ridge.

I don't have a single little gas thing on my feedlines. All of the protection is in entrance panels and wiring, tower grounds, and buried cables. Every week for the past few weeks there has been at least one direct hit here.

http://www.w8ji.com/ground_systems.htm

73 Tom

Better add an e-commerce page to your Web site, Tom. It should offer highchairs, tall stools, and tall ladders for sale.

It seems your advice about grounding constantly goes over some peoples' heads. Maybe if they stood on a chair, they'd finally get the point.  Wink
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AA4HA
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« Reply #18 on: July 14, 2011, 01:55:56 PM »

I have a similar situation.  I live in the middle of 700 acres.  The 14KV primary power line that feeds my house is a mile long and runs through open fields.  I am the only house on the power line and of course I am at the end.  Being at the end is never a good thing.  I have had 3 major lightning events in the past year with damage totalling over $15,000.

Recently (at my request) the local power company spent 2 days "inspecting and rebuilding" the mile long power line.  They found many problems on their side.  The major one was many poles did not even have a ground wire on them - never did.  They installed 40 foot deep ground rods and lightning arrestors on the 5 poles before the end of the line.  They made sure every pole on the line had a decent ground.  They installed a lightning arrestor on every third pole all the way out to the highway.

I took a direct lightning strike on the house yesterday afternoon at 15:30 hrs when a storm blew through. Damages so far are two wall-wart power supplies and the power supply on my main computer. The little computer UPS was completely overwhelmed. The bigger UPS supplies on the television and satellite TV system survived just fine, I lost one of those wall-warts for a video to Ethernet converter and another wall-wart for an Ethernet switch upstairs in a service closet.

Several breakers jumped open, some of the GFCI outlets needed to be reset and my fire alarm system went off. It definitely backfed into the distribution power system as a recloser at the other end of the distribution line tripped and required that Southern Co send someone out to manually reset it.

As things go, it was a very small strike, just enough of a "Pop" and "flash" to let you know that the thunder Gods were still awake. No flames, no smoke, no radio damage (antennas were all disconnected anyway). For a while, my clothes dryer "became all mental" but after resetting that device it seems to be working (for now).

This happens 2-3 times a year and even now I can hear the thunder rumbling out there.

I have a whole-house TVSS in the breaker panel, in addition to a bunch of plug-in MOV's, surge protected power strips, etc... The only inconvenience is the PC power supply. The replacement should be here tomorrow, just hope it did not toast the motherboard. Good thing it happened before I put the new NVIDIA GTX-590 video card in the machine. I was going to have to go to a 1 KW power supply anyway because of the video card requiring almost 700 watts by itself.

The radio room is handled by twin 3 KVA UPS supplies that are each connected to a 200 A/ Hr, 48 volt battery string. Normally I leave the master breaker off except for a small supply that keeps the rubidium reference oscillators running. (those take a few days to get completely stable, a bunch of my gear uses a 10 MHz reference oscillator). There is a battery string to keep the 24 volts going to those things too.

One piece of gear I always worry about is that Harris RF-382 ATU that is out at the 43' vertical. I hardened it as best I could by adding internal MOV's, TVSS diodes and series chokes on the control cable. that multi-pin round connector is not so easily disconnected so I made a bulkhead entrance protector at the copper ground plate that replaces the lower 6" of the radio room window.

The beverage antennas are always taking damage. For a while I was losing baluns right and left until I started to wind my own 9:1 baluns with a heavier gauge wire. Still I will loose a terminating resistor (big, 100 watt non-inductive resistors at the end of the antenna runs). I made arc-horns to mitigate some of the damage so surges can flash around the terminating resistors. Usually it flashes over at the ceramic insulators that are screwed into the trees that run out there.

Everything is bonded and grounded (lots of copper in the ground). The problem was the lightning taking a path from one of the lightning rods, down the 2" copper strip to the earthing system. I even bought a bunch of copper "deck grating" and have that buried to supplement the system. I am going to convert the omni antenna ground radials to buried grids (pig-fence mesh).

Most of the lightning damage I catch comes in on the Ethernet connections and blows out ports on the switch. This was a rare one for not costing me another 32 port switch. Someday I will migrate it all over to fiber optic (have it in the walls, just the media converters are too expensive).

I am going to replace the whole-house TVSS. It has been in there for about 5 years and has absorbed many strikes. Those MOV's will either get soft and burn open or fail in a shorted state.

Not as a product endorsement but here is what I use ( http://www.smarthome.com/48390/Whole-Home-Service-Entrance-Surge-Protector/p.aspx )

The utility ground here is "awful". There is only about 12-18" of sandy topsoil on top of a few feet of sandstone that overlays about 600 feet of limestone (karst "ridge and valley" geology). The utility pole ground is "a nailer" (flat copper disk nailed to the bottom of the pole) and the pole is set in a hole that was blasted about 4 feet deep and backfilled with rock-rubble. I had to resort to trenching open all around the house, all the way down to bedrock and burying about 150' of 2" copper ground strip that is bonded at the corners to 4' steel coated ground rods that I had to use a core-drill to make a hole to pound the rod into. The soil is also doped with Epsom salts and copper sulphate before I backfilled.

I can "grow rocks" or trees that can get by with a shallow root system. Some must have penetrated into cracks in the sandstone for an anchor, otherwise the entire place would blow over in a wind-storm. It is not land that has any use for farming so I left it all as forest. It is as about as bad of a grounding system that I have seen other than some mountaintop microwave sites out west where there is no topsoil at all.

Tisha, AA4HA
« Last Edit: July 14, 2011, 02:49:23 PM by AA4HA » Logged

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
K8AXW
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« Reply #19 on: July 14, 2011, 08:49:09 PM »

Tisha:  Have you ever thought about moving!!!!!!
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AA4HA
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« Reply #20 on: July 15, 2011, 01:08:05 PM »

Tisha:  Have you ever thought about moving!!!!!!

Not many other places where I can own so much acreage for antennas! None of those 'stinkin HOA's or covenants up here. My high spot is at 1033 feet where "town", two miles away is at 508'. My longest beverage antenna is 3120' long.

There are trade-off's. I cannot see a single street light or another house from where I live, I hear no traffic and the wild things rule the night. If I want to mow my yard once a month I do not have code enforcement people jumping down my back.

Tish
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
HAPLO
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« Reply #21 on: July 18, 2011, 07:13:22 PM »

So, if I have lightning rods on my house now, I have a few questions:

1) How do I know if the ground rod is deep enough, and is still at a low enough ohm-age to be considered a good ground? Ie: How do I test it, since I wasn't the one that installed it?

1a) Should I tie the ground rod from my electrical panel to the ground rod for the lightning rods? (Presently, it isn't)

2) The lightning rods on top of the house are connected together, with one line (3/4" braided copper) from them going to a ground rod. If I use an antenna mounted on my roof, is the massive amount of copper crossing my roof going to affect my radiation pattern from my antenna?

3) Should I tie my antenna into the nearest part of my lightning rod system on the roof, or run a separate line down to the ground rod in the ground? (I certainly am not going to buy 3/4" copper braid to run all that distance!) Smiley

Thanks everyone,
H.
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W8JI
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« Reply #22 on: July 19, 2011, 03:52:03 AM »

1) How do I know if the ground rod is deep enough, and is still at a low enough ohm-age to be considered a good ground? Ie: How do I test it, since I wasn't the one that installed it?

Testing the ground resistance is difficult and probably not very meaningful since DC or low frequency AC resistance does not tell us how low the path impedance is or if it is proper for lightning.

Quote
1a) Should I tie the ground rod from my electrical panel to the ground rod for the lightning rods? (Presently, it isn't)

Sounds like a poor installation. Too bad people installing things like that have no idea how to install the system.

Code for lighting grounds is at minimum a rod at each end of the house (two 8 foot rods spaced 8 feet at each end preferred), with the grounds at diagonal corners, with one ground near the service entrance so it can be bonded to the service entrance ground. Anything else entering the dwelling, like metal pipes or antenna cables, has to be bonded in to the service entrance ground. There are spacing distance requirements also, but clearly your installation is not to code.


Quote
2) The lightning rods on top of the house are connected together, with one line (3/4" braided copper) from them going to a ground rod. If I use an antenna mounted on my roof, is the massive amount of copper crossing my roof going to affect my radiation pattern from my antenna?

Sure it will. How must depends on the antenna and where it is installed.

Quote
3) Should I tie my antenna into the nearest part of my lightning rod system on the roof, or run a separate line down to the ground rod in the ground? (I certainly am not going to buy 3/4" copper braid to run all that distance!) Smiley

Braiding is the poorest type of conductor for lightning. Solid smooth surface wire or wide flashing is best. It the lightning rods were installed properly you could ground to their ground buss. Code requires any cables entering the house or Ham antenna ground to be bonded to the mains entrance ground.

Whoever installed your lightning rod system violated national fire protection codes as well as publicized recommendations for lighting rod grounds.

73 Tom


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HAPLO
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« Reply #23 on: July 19, 2011, 09:13:00 AM »

Whoever installed your lightning rod system violated national fire protection codes as well as publicized recommendations for lighting rod grounds.

Tom,

My house was built in 1893, the ground rods on the house look VERY old, so I image their installation is well before most of the code standards.  Wink

So, knowing what you know about my installation, would you bond the existing lightning ground rod to the main's ground rod, and trust that with the antenna ground? Or would you sink another ground rod where the main's rod is at, and bind all three together?

H.
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W8JI
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« Reply #24 on: July 19, 2011, 03:14:57 PM »

Whoever installed your lightning rod system violated national fire protection codes as well as publicized recommendations for lighting rod grounds.

Tom,

My house was built in 1893, the ground rods on the house look VERY old, so I image their installation is well before most of the code standards.  Wink

So, knowing what you know about my installation, would you bond the existing lightning ground rod to the main's ground rod, and trust that with the antenna ground? Or would you sink another ground rod where the main's rod is at, and bind all three together?

H.

To meet current standards, the lightning rods are supposed to be binded to the mains ground plus have another feed from roof down to ground at the opposite end of the house, and no more than 100 feet apart.

Also current code is that the station entrance ground that all cables entering the house are binded to should be bonded to the mains ground.

I would also upgrade the grounds.

73 Tom
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N4NYY
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« Reply #25 on: July 20, 2011, 12:50:24 PM »

Quote
get hit all the time here. I have a 318 ft tower and a bunch of other towers that are the tallest things for miles, and I am on a slight ridge.


OK. You know that that means. The next time you service your tower, you need to put up a remote camera.
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W8JI
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« Reply #26 on: July 20, 2011, 01:31:21 PM »

Quote
get hit all the time here. I have a 318 ft tower and a bunch of other towers that are the tallest things for miles, and I am on a slight ridge.


OK. You know that that means. The next time you service your tower, you need to put up a remote camera.

I'm trying to figure out how to get pictures with my Cannon Rebel T2I. I need some sort of auto-trigger.
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WA3SKN
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« Reply #27 on: July 20, 2011, 01:34:59 PM »

Consider having your lightning rod system inspected.  A high resistance ground and lightning rod combination is not a good way to start!

-Mike.
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N4NYY
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« Reply #28 on: July 20, 2011, 02:06:46 PM »

Quote
I'm trying to figure out how to get pictures with my Cannon Rebel T2I. I need some sort of auto-trigger.

Ha !    http://hackaday.com/2011/03/26/automatic-trigger-for-lightning-photography/

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KE5JDJ
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« Reply #29 on: July 23, 2011, 09:56:06 AM »

.....
I live in an old country home on a hill, in the middle of a field, that has several lightning rods on it. I have 7 very tall trees around my home too. I've lived there for the last decade, and have personally witnessed one of my trees get hit twice since I've been there. So, putting up an antenna has me concerned about lightning protection.
.....

Just for information, is being in the middle of a field also mean you are encircled by a metal (barbed wire) fence?  My observation is that being encircled with fence wire tends to concentrate lightning strikes.
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