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Author Topic: ground rods for antenna  (Read 952 times)
KB1NKJ
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Posts: 10




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« on: April 29, 2010, 07:25:52 AM »

I had to move my 2meter jetstream antenna from location at house to garage a 100ft away . to ground the .antenna mast will one ground rod do it or are more needed(gravel and clay here) . will I need a coax ground block at that point and will I need to ground all to electric service rod. I use battery power for radio so it is not plugged into electrical system of house I have a lightening arrestor and 3 -8ft ground rods  where original antenna setup was on house. can I use these rods or are they too far away from ant mast?

               73's KB1NKJ
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K9ZF
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Posts: 76


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« Reply #1 on: April 29, 2010, 02:15:43 PM »

Amateur radio station grounding can be a very complicated subject.  Whole books have been written on this, and most of the ham folklore is wrong!

Aside from buying books to learn about the subject, I would recommend starting here:

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

And remember, google is your friend Smiley   Just don't take everything you read at face value.  Do some research and learn to separate facts from folklore...

Good luck with your station!

73
Dan
--
Amateur Radio Emergency Service, Clark County Indiana. EM78el
K9ZF /R no budget Rover ***QRP-l #1269 Check out the Rover Resource Page at:
<http://www.qsl.net/n9rla> List Administrator for: InHam+grid-loc+ham-books
Ask me how to join the Indiana Ham Mailing list!

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--
K9ZF
Amateur Radio Emergency Service, Clark County Indiana. EM78el
The once and future K9ZF /R no budget Rover
 ***QRP-l #1269
Check out the Rover Resource Page at:
<http://www.qsl.net/n9rla>
List Administrator for: InHam+grid-loc+ham-books
Ask me how to join the Indiana Ham Maili
K0ZN
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Posts: 1544




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« Reply #2 on: April 29, 2010, 08:26:36 PM »

Hi.

There are probably more threads here on Eham about grounding than any other subject. Dig around in the archives and you will find all kinds of good info and discussions.

Short version:  NO.  ONE ground rod is not enough to give real lightning protection. You are trying to dissipate MEGAWATTS; one rod isn't going to do that. If you are seriously interested in protection, you probably need 3 and they should be spaced apart by a distance of the length of the rods, plus maybe a foot or two. You also need HEAVY copper cable for the system. AWG # 4 would probably be a minimum size for GOOD protection.

It is imperative that you bond the whole radio system, AC power line ground, etc. together. Improper grounding can actually increase lightning damage. W8JI's site is a good place to start. Polyphaser also has a good book on the subject.

Just keep in mind that if lightning hits, the lightning WILL find ground. The only question becomes what path it takes to ground.....through a good, well designed ground system or through your rig, shack, house wiring, telephone, cable TV wires, water pipes, etc.

73,  K0ZN
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KB1NKJ
Member

Posts: 10




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« Reply #3 on: April 30, 2010, 03:18:10 AM »

thank you both for the help. will check out site recommended.

                  73's  KB1NKJ Smiley
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AA4HA
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Posts: 1386




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« Reply #4 on: April 30, 2010, 06:41:42 AM »

If you want the Polphaser book I can email it to you. For more information beyond that I have 68 different documents (104 mb) up on my dropbox (file sharing) site.

This includes the entire array of Polyphaser documents, military grounding and EMP protection manuals, Eaton grounding manual, NASA grounding manual and several documents in how to test your ground system.

To get to the dropbox you will need to install their software. You can use their referral link https://www.dropbox.com/referrals/NTYyNDg4NzA5 so I can continue to offer this up for free. The program puts the entire dropbox up to you on a web site that you can download from. Then shoot me an email at Tisha.Hayes@gmail.com for an invite to the archive. There are nineteen other hams who currently have access to the site and many make contributions (that I scan for viruses before they go into the public directory).

Tisha Hayes, AA4HA
« Last Edit: April 30, 2010, 06:44:24 AM by Tisha Hayes » Logged

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
K9KJM
Member

Posts: 2416




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« Reply #5 on: May 01, 2010, 10:35:47 PM »

What are you going to use for coax feedline?  To extend the antenna more than 100 feet away from where it is now means you will have a total of 150 or so feet of coax feedline???
Even with the "good" coax, Times LMR400 the loss is getting too high at two meters, Let alone 440.......   For anything longer than 100 feet you really need to consider some good used Heliax, Or some surplus CATV hardline.
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