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Amateur Radio Antennas For discussion of all amateur band designed antennas and related accoutrements. This includes base, handheld, mobile and repeater usage. For commercial antennas on the amateur bands please use Commercial Radio Antennas below.

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Old 07-23-2014, 9:06 PM
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Default Gutter Random Wire Counterpoise/Ground Help?

So I just ran a 14g solid copper wire to my Aluminum downspout, thinking to try a gutters/downspounts random wire antenna. I'll work on bonding the sections later - they are riveted at least.

I can't lay out an external counterpoise or radials, so am getting a MFJ-931 Artificial Ground MFJ Enterprises Inc. between the wire and antenna tuner. The choice appears to be throw down a counterpoise wire inside, or connect to ground. It comes to mind I have a forced hot water heating system and a copper radiator pipes is right by my rig.

Are there any preferences for a wire counterpoise vs connecting to the pipe for ground?
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Old 07-23-2014, 9:51 PM
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Are you going to transmit into this setup? If so, expect some RFI/TVI generation. You may light up your TV, radios, and the neighbors with RF. But that may be OK if you and anyone else don't mind. I've seen advice not to use hot water / heating systems for ground, but may be OK for RF counterpoise, though not a protective ground. And how did you make the connection from the copper of the coax/feedline to the aluminum of the gutter? If not really tight, and exposed to the elements... the dissimilar metals may corrode into a makeshift diode with unpredictable passive re-radiation effects when transmitting. Not saying a gutter antenna is a bad idea... just need to proceed carefully.
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Old 07-23-2014, 10:12 PM
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Expanding on what popnokick said a random wire antenna needs a counterpoise (or RF ground) and your water pipes would not make a very good RF ground. The RF ground needs to be a "field" underneath your antenna. So as popnokick said be prepared for RFI/TVI. A ground is not a counterpoise but both need to be connected to your house electrical ground as required by the NEC. Also connecting copper to aluminum requires a CU/AL type of approved connector for best results.
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Old 07-24-2014, 6:09 AM
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For the connection, I took off the downspout paint with a Dremel wire wheel, then used a self-tapping screw with two inside/outside star washers, the bottom one grinding into the Al downspout and the copper between that and a second washer. I then soldered the wire/washer/screw set once installed on the downspout.

My rig is just inside a window on the ground floor, and I ran a heavy tinned copper brain ground strap from my window pass-thru to a 8ft copper-clad rod driven into the ground. Another heavy copper braid runs to my antenna tuner ground, and I tie all other stuff to that common ground point.

The problem I face is my wife's garden is right outside the window, and she doesn't want me running a bunch of wires around as counterpoise or radials in her flower beds.

Just a thought and another question: Where would a counterpoise wire tie into my gutter antenna system - at the gutter, at the pass-thru or at the antenna tuner? I might get away with a counterpoise wire running along the perimeter of the house. The concrete foundation comes up about 3ft from the ground before the vinyl siding starts. I could run a wire just at the lower edge of the siding, which would parallel the roof gutter.
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Old 07-24-2014, 9:56 AM
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I see a couple of potential problems from your description. A counterpoise should attach to the feedpoint of the antenna, which in your case would be the tuner ground.

Your rain gutter and one counterpoise would make a dipole with RF current flowing on both elements and they will both radiate. If the single counterpoise is not a 1/4 wave or multiples, RF current will also flow on your coax and it will radiate. If the counterpoise wire is long and grounded at the end you have a really unbalanced dipole and RF will probably flow on the coax and radiate. It takes two or more counterpoise wires or ground radials, preferably equal length and running in opposite directions to cancel RF currents so they will not radiate (especially in the house).

Another problem is a ground rod for an antenna or radio that is not connected to the main house ground, it can be at a different potential than the house ground and AC current can flow between the power supply line cord, radio and tuner chassis and wire heading to the isolated ground rod. The voltage potential can be substantial in some cases can hurt you. The National Electrical Code also requires all antenna ground rods to be bonded to the house AC electrical ground.

A rain gutter can make a fine antenna and I think the best way to light it up would be placing a remote auto tuner outside at ground level and feed the downspout. Then run multiple counterpoise wires heading in opposite directions along the perimeter of the house if you can't run them outward through flower beds, etc. This gets the entire radiating part of the antenna outside and hopefully away from computers and other RF noise making equipment.
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Old 07-24-2014, 6:38 PM
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I'm starting to go negative on gutter random wire antennas! But not due to he very helpful comment's y'all have made - many thanks for you thoughts.

I've just considered that I might put up an antenna, not on my house, in my yard, or at the tree line at the edge of my yard, but on the other side of my HOA's tree buffer-zone which faces a large empty field. It's about 150ft from my rig to the tree-line, but it's also 30-ft uphill, so higher than my roof by that 30ft plus tree height.

I'll take the next questions off to a new thread. Thanks for the help here!
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Old 07-26-2014, 5:04 PM
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I did go ahead and give the gutter antenna a try, despite my misgivings. I ran 1/4 wavelength 22g wires for 10M, 17M, 20M 40M as counterpoise from my tuner ground out the window and along my foundation, a few feet above the ground. I did some listening and can barely find an intelligible signal. So I guess I'll get a real antenna!

Just a question on station ground. Yes, I'm grounding through a rod outside the window from my rig, rather than my house AC ground on the cold water pipe. The distance for that ground would be 30ft vs 13ft for the rod. Still better to ground to the cold water pipe used for hosue AC ground?
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Old 07-26-2014, 5:15 PM
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Quote:
Originally Posted by MaverickNH View Post
I did go ahead and give the gutter antenna a try, despite my misgivings. I ran 1/4 wavelength 22g wires for 10M, 17M, 20M 40M as counterpoise from my tuner ground out the window and along my foundation, a few feet above the ground. I did some listening and can barely find an intelligible signal. So I guess I'll get a real antenna!
Give it a few tries, to make certain you are not judging during a poor propagation time.

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Originally Posted by MaverickNH View Post
Just a question on station ground. Yes, I'm grounding through a rod outside the window from my rig, rather than my house AC ground on the cold water pipe. The distance for that ground would be 30ft vs 13ft for the rod. Still better to ground to the cold water pipe used for hosue AC ground?
Is the water pipe your ground? The NEC has moved away from this practice, due to varying pipe materials. (It is allowed, if you verify the pipe is metal, and a minimal specified length.)

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Old 07-26-2014, 5:29 PM
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My AC panel is grounded to my copper cold water pipe by a 6g wire bolted on above and below house entry that tunnels about 3 feet below ground level in a trench blasted through granite to the street tie in. I'd guess the trench was filled with gravel and rocks. My 8 foot ground rod is driven into a mix of soil and granite rubble about 20 feet from the cold water pipe (but 30 feet for a tie in due to vertical delta).

Yeah - I'll keep trying on the gutter HF listening...
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Old 07-26-2014, 5:40 PM
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Your plumbing is NOT a ground. Your Electrical ground is and it is located at your meter or service entrance panel. As Krokus said the NEC requires your plumbing (if metal i.e copper; steel etc) to be connected to your Electrical ground. With many new houses being built with non-metal plumbing there is nothing metal to connect to. Any additional grounds are required to be connected to your Electrical ground by the NEC (satellite dish, telephone, cable tv etc). Your radio equipment needs to be grounded to your electrical ground along with any and ALL other ground rods you have installed. They should be "home runs" to prevent daisy chain ground loops. This is what is called "single point" grounding. As a practical matter the closer your ground rods are to your electrical ground the less chance there is for a potential difference to occur. That practical distance would be around 8 to 16 feet depending on the "quality" of your ground. However if it was me I would follow the NEC and make a home run connection from each ground rod to my electrical ground.
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Old 07-26-2014, 5:52 PM
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Well, now I'm confused. My AC panel has a #6 copper wire coming out and bolted to the water supply pipe entering my basement foundation, but that's NOT the electric ground? The plumbing ties to the electrical ground, but the plumbing is not the ground? Where does the electrical panel make "ground"?

I'm not saying I think you're wrong, as I just don't know. I'm just wanting to confirm that I'll need an electrician to run a an appropriate ground conductor from AC panel to my rig as a common ground site for my equipment - that's 40 feet from my rig to the panel. The ground rod, I guess I would just pound into the ground all the way and let it corrode.
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Old 07-26-2014, 8:19 PM
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Your underground water main may be a better ground than the ground rod at the service panel, but the service panel ground is your main AC ground. Bonding the water pipe to it is good practice and can lower the ground resistance and put the pipes at the same potential for safety.

NEC requires you bond any additional ground rods to the service panel ground to make sure everything is at the same potential and you can have quite a voltage on a rouge ground rod compared to your service panel ground.
I had about 90 volts between a ground rod that was closer to my neighbors AC panel than my own panel, when reference to my house ground. I got a shock any time I disconnected the radio attached to that ground rod and eventually bonded it to the main ground, although it was quite a distance away.
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Originally Posted by MaverickNH View Post
Well, now I'm confused. My AC panel has a #6 copper wire coming out and bolted to the water supply pipe entering my basement foundation, but that's NOT the electric ground? The plumbing ties to the electrical ground, but the plumbing is not the ground? Where does the electrical panel make "ground"?

I'm not saying I think you're wrong, as I just don't know. I'm just wanting to confirm that I'll need an electrician to run a an appropriate ground conductor from AC panel to my rig as a common ground site for my equipment - that's 40 feet from my rig to the panel. The ground rod, I guess I would just pound into the ground all the way and let it corrode.
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Old 07-26-2014, 8:28 PM
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Quote:
Originally Posted by prcguy View Post
Your underground water main may be a better ground than the ground rod at the service panel, but the service panel ground is your main AC ground. Bonding the water pipe to it is good practice and can lower the ground resistance and put the pipes at the same potential for safety.

NEC requires you bond any additional ground rods to the service panel ground to make sure everything is at the same potential and you can have quite a voltage on a rouge ground rod compared to your service panel ground.
I had about 90 volts between a ground rod that was closer to my neighbors AC panel than my own panel, when reference to my house ground. I got a shock any time I disconnected the radio attached to that ground rod and eventually bonded it to the main ground, although it was quite a distance away.
prcguy
Thanks for that. We're having an electrician in for other work soon, so I'll ask him to bond my rig in compliance with standards. Y'all saved me from an eventual zapping!
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Old 07-26-2014, 11:08 PM
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One thing you need to remember with a rain gutter, is to make sure all connections are bonded, continuity works better than none at all. I've run counterpoises around the radio room, along the floorboards and under carpets and had great success keeping my RFI to a minimum. I used a rain gutter before (as I posted in your previous started thread) and it worked okay for what it was. I had a wire running between the front and rear gutters and that worked.
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