VOODOO42
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« on: December 17, 2008, 03:08:13 PM » |
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Going to start working on my shack....I am new to station building and have read sooooo many different theroies on how and why to ground a certain way. Here is what will be easiest for me and seems to go along with some of the ideas out there...can anyone tell me if this is not ok for rf grounding? I am basing this not on safety,but on the idea that stray rf can build up on chasis,line,yadda yadda yadda.
For my ground bus I am going to use 5/8 roll soft copper to run across my work bench and then up my wall 4 feet. I am then going to use a short piece of #4 copper to run through the wall to 3 ground rods. Each piece of equipment bonded to the roll copper with flattened roll copper and holes drilled in the ends for attachment. I know some say to bond to the house cold water and som say not to. My antenna is about 120 feet away from the shack so they would not be bonded to the same ground anyway.
Any ideas before I get at it would be appreciated, Thanks.....screaming voodoo
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KB9CRY
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« Reply #1 on: December 17, 2008, 03:59:36 PM » |
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Sounds good to me. At the ground rods outside, you bond your lightning arrestors which are on every cable coming into the shack. Then you run that #4 wire outside and around to the electrical service entrance ground. The water pipe bond is not really required.
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VOODOO42
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Posts: 114
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« Reply #2 on: December 17, 2008, 04:19:56 PM » |
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The cold water pipe is my house ground. There is no rod driven for the electrical panel. should I ground to the cold pipe also as well as my rods I will drive outside.
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K9KJM
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« Reply #3 on: December 17, 2008, 10:51:19 PM » |
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While 5/8" soft copper tube would make a dandy ground conductor, That seems kind of expensive to me. You should be able to save lots of money using the best material for grounding, FLAT COPPER STRAP. Usually available as copper roof flashing at home supply stores. And you DO NEED To bond ALL of your grounds together!! For some good info: http://members.cox.net/pc-usa/station/ground3.htm
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KB9CRY
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« Reply #4 on: December 18, 2008, 11:38:32 AM » |
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What exactly do you mean the cold water pipe is your house ground? Describe exactly.
You may have an older house and may need to bring it up to modern codes. A call to the electric company is warranted.
Any bonding to any ground must be done outdoors, from ground rods to whatever.
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N1QOQ
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« Reply #5 on: December 18, 2008, 02:08:27 PM » |
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Metal cold water pipes where the only grounding electrode required until the mid 80's in most juristictions. They are still a required electrode (where they exist) in conjunction with 2 ground rods in the NEC. Bond all your grounds together.
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VOODOO42
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« Reply #6 on: December 18, 2008, 06:37:59 PM » |
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actually the cold water pipe is fine...... I am a licensed home inspector in the state of NC and no upgrade is needed for the electrical. It is the Rf that I amconcerned about.
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KB9CRY
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« Reply #7 on: December 19, 2008, 02:50:33 AM » |
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You are confused. You mention RF ground but talk about safety/lightning ground. Do some more homework, ie search on the main forums page, for the differences between RF grounds and safety ground. They are two totally different things.
And, I'd recheck on what NEC allows for electrical grounds.
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N1QOQ
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« Reply #8 on: December 19, 2008, 07:19:00 AM » |
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In the business of home inspecting, I am sure you realize that as an existing condition,utilizing the water main as you sole ground is fine. But as a licensed electrician and municipal inspector in MA, I will advise you to upgrade your grounding system to current NEC standards. Amatuer transmitting stations are covered by the NEC by name. Even though RF and your saftey ground are two seperate issues, they are also electricaly connected, and will serve to enhance each other. Installing rods at your service entrance will serve to reduce the resistance in the total grounding system. Ground and bond everything.
73 Paul
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AA4PB
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« Reply #9 on: December 19, 2008, 07:28:23 AM » |
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If you have a properly designed antenna system then there is no need for an RF ground at the radio. Stray RF does not build up on the chassis. If you have RF on the radio chassis it is because there is RF flowing on the outside of the coax shield or the antenna is too close to the shack. It is next to impossible to provide a good RF ground at the radio unless your radio is setting on the ground and connected to radials. Any length of wire will have inductance which will cause the radio to become "ungrounded" RF wise at some frequency.
If you have a balanced antenna like a dipole or a yagi then no RF ground is needed anywhere. If you have an unbalanced antenna like an end-fed wire or 1/4 wave vertical then the RF ground needs to be outside at the base of the antenna in the form of radials.
Remember, the above discussion is about "RF grounds" and NOT safety or lightning grounds - a different issue entirely.
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VOODOO42
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Posts: 114
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« Reply #10 on: December 19, 2008, 08:49:04 AM » |
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Thanks aa4pb.....that makes good sense. And Thank You for reminding the kind folks out there that the question was about rf ground and not electrical or saftey. I know it is easy (for some)to stray from the main points from time to time on certain questions but that only helps to confuse people like me that are trying to learn.
Thanks Again, screaming voodoo42
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KB9CRY
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« Reply #11 on: December 20, 2008, 02:43:37 AM » |
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But, I'll also say it again, the question you were asking about has nothing to do with RF grounding. Ground rods and water pipes are not effective RF Grounds, those come into play with Safety or Lightning Grounding.
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W3LK
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« Reply #12 on: December 20, 2008, 07:05:22 AM » |
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"screaming voodoo"
Call sign?
73,
Lon - W3LK Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
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VOODOO42
Member
Posts: 114
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« Reply #13 on: December 20, 2008, 08:10:51 AM » |
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That is the question that I was asking......do I need to bond my bus bar (soft roll) to the main ground also to be effective for keeping stray rf off of the equipment and line or would it be ok with the plan that had to go straight through the wall and drive some ground rods. That was all I needed to know. I was asking because I do not know. I am starting to get my station plans together and I would like to do it correctly. I appreciate your concerns about my house electrical panel being up to the NEC current standards......I really do. I may have some questions on that topic at another time. For safety issues, I will probably call a licensed electrical contractor in my area.
Thanks for the input.....all posts have been helpful. voodoo42
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VOODOO42
Member
Posts: 114
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« Reply #14 on: December 20, 2008, 08:30:16 AM » |
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Hey W3LK.......I am studying for my tech test at the present, with hopes of passing in January. I am wanting to get things right before throwing something up and trying to figure out my problems later. On the ground issue i have read many posts that go in so many different dierctions it was confusing. The website K9KJM posted answered my rf grounding issue clearly and straight to the point...and it has a great amount of info on safety grounding as well... that I will be refering to.
Right now my plan is to get (probably) an Icom 160-10m radio or something similar and some type of wire dipole antenna. I don't want to sink tons of money into it now but I do want to be able to get out well and make some contacts. I fgure once I get my "general" I will be able to do quite a bit more and have some fun. It will take time...but I'LL get there. And hopefully not make too many mistakes in the proccess. Thanks...voodoo42
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