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Author Topic: What would you suggest for lightning and EMF protection  (Read 6938 times)
KB1PXU
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Posts: 33




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« on: April 16, 2012, 02:38:59 PM »

I'm getting ready to put up a new Buckmaster 7 band dipole.  The last one was zapped by lightning.  The feed cable will be LMR400 Direct Burial as I have reloacated my dipole further from my house. I'm thinking of using ALPHA-DELTA ATT3G50N 200W TO 3 GHZ SURGE PROTECTOR N in the feed cable and grounded to the grounding rod for my electrical service.  Last time I used an ICE Electronics device; however, the Alpha-Delta allows easier changing of the protective cartridge if necessary.

Additionally I am thinking of a Times Microwave - Ground Kit for LMR-400 Mfg Part #: GK-S400TT which would be strapped onto the cable and also grounded to the same grounding rod.  I believe this grounding strap is normally used with antenna towers.  Do you think this is a good idea to use as I described?

Lastly I am thinking of using an Alpha Delta Coax Switch Wall Mounted to a copper bar as done by KF7P Metalwerks.  This way when the antenna is not in use I would disconnect the cable from the Coax switch and the feed cable into the room would still be grounded.

Lastly and this is probably the strangest right outside the room I use for my operations is a downspout for rain.  This downspout is pure copper.  I was thinking of connecting my copper grounding bar in my room to the downspout which terminats at ground level within inches of my service ground.  I could easily strap it to the ground.

What parts above do you think are viable?

73
Will
KB1PXU         
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N4JTE
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Posts: 1158




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« Reply #1 on: April 16, 2012, 05:05:31 PM »

To be honest NOTHING will protect the antenna/ equipment from a direct hit from lightning. After 25 years in florida, I could only sleep at night with all feedlines disconected and away from everything during the storms. Took everything out of the 120v outlets for close encounters of the worst kind.
Bob
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K9IUQ
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Posts: 2053




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« Reply #2 on: April 16, 2012, 05:29:22 PM »

Do you think this is a good idea to use as I described?
Will
KB1PXU         

My property got hit by lightning once. Now when a storm is predicted, I disconnect all equipment, put it all back in original boxes.. I then put the boxes in another room, away from windows and any metal. I disconnect and ground all antennas,phone line and cable internet and satellite dish. I unplug everything from 110/220v outlets. Then I crawl under the bed with my 2 dogs and hope I do not get hit by lightning again.

Even these precautions are not foolproof..  Cheesy

Stan K9IUQ
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KB1PXU
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Posts: 33




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« Reply #3 on: April 16, 2012, 06:40:38 PM »

I usually disconnect everything also.  I unplugged everything but forgot to remove the feedlines - thst'd when  I got hit. 

Nothing is perfect but still wondering about my suggestions. 
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WB4SPT
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Posts: 161




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« Reply #4 on: April 16, 2012, 07:02:27 PM »

I'm getting ready to put up a new Buckmaster 7 band dipole.  The last one was zapped by lightning.  The feed cable will be LMR400 Direct Burial as I have reloacated my dipole further from my house. I'm thinking of using ALPHA-DELTA ATT3G50N 200W TO 3 GHZ SURGE PROTECTOR N in the feed cable and grounded to the grounding rod for my electrical service.  Last time I used an ICE Electronics device; however, the Alpha-Delta allows easier changing of the protective cartridge if necessary.  OK, won't hurt.

Additionally I am thinking of a Times Microwave - Ground Kit for LMR-400 Mfg Part #: GK-S400TT which would be strapped onto the cable and also grounded to the same grounding rod.  I believe this grounding strap is normally used with antenna towers.  Do you think this is a good idea to use as I described?  Need a plan to get a ground strap to the electrical main ground rod.  Grounding to a single ground rod is inadequate.

Lastly I am thinking of using an Alpha Delta Coax Switch Wall Mounted to a copper bar as done by KF7P Metalwerks.  This way when the antenna is not in use I would disconnect the cable from the Coax switch and the feed cable into the room would still be grounded.  I use the metalwerks outdoor mounted steel box that has the copper back plate.  I think they are a great idea; i've got the copper plate connected thru 2" x .035 copper strap to the house entrance ground rod.

Lastly and this is probably the strangest right outside the room I use for my operations is a downspout for rain.  This downspout is pure copper.  I was thinking of connecting my copper grounding bar in my room to the downspout which terminats at ground level within inches of my service ground.  I could easily strap it to the ground.  Yeah, there is merit in getting all "flashover" objects bonded.  Not sure it helps the radios that much, but if it's in the vicinity, take advantage of it.  BUT, one ground rod is not near enough conductivity to ground

What parts above do you think are viable?

73
Will
KB1PXU         
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KE6EE
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Posts: 448




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« Reply #5 on: April 16, 2012, 07:14:54 PM »

For some people, prayer is reported to be very effective.  Grin
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K4SAV
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Posts: 1850




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« Reply #6 on: April 16, 2012, 08:34:18 PM »

n the case of your antenna system, the posters humerous paranoid responses are close to accurate  Smiley, but they aren't telling you why (which doesn't do you much good for correcting the problems or even understanding the problems).   The main problem is that coax cable can't handle a direct lightning strike, and that is apparently what you have.  The coax will disintegrate when it gets hit and the lightning will follow whatever path it likes after that.  

The best bet for a dipole is a metal mast at the center of the dipole, which the coax is run down so that lightning will jump to the metal mast, or hopefully hit the mast instead of the dipole.  Then you need several ground rods at the mast base, and all the other proper grounding (which I will omit the description), but it is the same as what you would do for a tower.  The dipole also has to be not near your house.  Yes, I know that's not practical for a lot of people, so if you are in that group, keep your insurance premiums paid up and hope you don't get hit often.

Wire dipoles, small wire verticals, trap verticals, trap dipoles, and feedlines don't survive lightning strikes if they are in the main lightning path.

I have a couple of inverted vees hung off my tower and they have never been hit, although the tower takes an average of about 3 direct strikes per year.  The lightning really likes that higher tower (which has a lightning rod extending above the top antenna by about 7 ft), but that's no guarantee the inverted vees will never get hit.  In that case I will lose a wire dipole but that should be all.  Direct hits on the tower haven't resulted in any damage yet.

Jerry, K4SAV
« Last Edit: April 16, 2012, 08:38:07 PM by K4SAV » Logged
K9KJM
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Posts: 2415




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« Reply #7 on: April 16, 2012, 11:11:19 PM »

Good advice from SAV.     

Put lightning to ground as close to the strike location as possible.   Space those ground rods about twice the distance apart as the depth.

Your list of parts seems OK to me,  Using the copper gutter would depend on IF there are any joints in it that could become a high resistance.

Remember that proper BONDING of all grounds is the most important part of protection. The actual devices used (Arrestors, Switches, etc) Are much less important. Your coax ground must be bonded with your tower ground, Mast ground, Electrical ground, Cable TV ground, Telco ground, etc.

To say that nothing can protect from direct lightning strikes is just silly.  Think of all the commercial radio and TV stations, Fire, Police, Cellular towers, Repeater towers, Skyscrapers with steel frames (With people inside them!) That all take direct lightning strikes every day with no damage to equipment.

IF you "Disconnect" any lines, Be SURE to properly ground those lines, Or you have just made your situation MUCH more dangerous!

Tips on how to do it all on a low budget:
http://www.scribd.com/anon-849269/d/14868226-lightning-protectiontaming-thors-thunderon-a-budget

(Give that site plenty of time to load)
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KB1PXU
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Posts: 33




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« Reply #8 on: April 17, 2012, 08:23:02 AM »

K9KJM -

Good article.  I guess I'm going in the right direction.  When I said I would disconnect lines that would make the rigs totally isolated  they would not be plugged in to any outlets as well as not attached to any antenna feed cables.  As in the article my feed cable comming in would then terminate at a switch which would be mounted to a central point ground exactly as described in the article. 

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K1CJS
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Posts: 6055




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« Reply #9 on: April 18, 2012, 04:09:14 PM »

Everything sounds OK--except for connecting to the downspout.  If someone were to be near or touching that downspout....  Safety first.  A downspout isn't expected to be connected to anything but the gutters and fastened to the house.
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KB1PXU
Member

Posts: 33




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« Reply #10 on: April 18, 2012, 05:24:03 PM »

Everything sounds OK--except for connecting to the downspout.  If someone were to be near or touching that downspout....  Safety first.  A downspout isn't expected to be connected to anything but the gutters and fastened to the house.

Very good point.  I totally agree.  Wasn't thinking that one through.  That's why this forum is valuable.

I just purchased today something called a   " Model UCGC Universal Copper Ground Rod Clamp for direct attachment of Model ATT/TT3G50 series surge protectors to your 5/8 ground rod. " It clamps right to the common ground rod.  Here's a link   http://www.alphadeltacom.com/.  Eliminates the further need to connect the coaxial surge protectors to the ground before entering the house.  Still need to ground the common point ground from the radio room back to this.   
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