| Author |
Message |
    
Barracuda
| | Posted on Sunday, March 30, 2003 - 2:17 am: | 
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Hi all,
I happen to live near the end of a penninsula surrounded by salt water. Is there any advantage to be had because of this and if so is there anything special I could do to take advantage?
For the record, the water is about 1/4 mile north and south, and about a mile west. To the east is the rest of the penninsula. Also the water table is about 6-8 feet deep under sand.
Thanks in advance
Barracuda
Breezy Point, NY |
Alsworld
| | Posted on Sunday, March 30, 2003 - 11:07 am: |
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Oh heck yeah. If you have a mobil radio in your vehicle, if you could park in the middle of a bridge or small island would be best. The water is the perfect ground plane to send (reflect) your signal off of. If those are not available, parking your vehicle very close to the water and talking that way will help.
If a base station, with the penninsula being 1/4 mile both N & S, I don't know if that's much help or not. I live very close to the intercoastal waterway but I think too far to help, unless I'm trying to shoot skip toward the southern hemisphere. From the feedpoint of my antenna, I can clearly see the intercoastal, the barrier island and the Gulf of Mexico.
Alsworld |
Barracuda
| | Posted on Sunday, March 30, 2003 - 6:27 pm: |
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Thanks Alsworld, I was thinking more for a base station application, but what you said regarding the mobile unit certainly makes much sense and I will put that to good use for sure. For the base though, I was wondering if grounding the antenna system down to the water table might be beneficial in some way because that is salt water connected to the surrounding waters. Just a thought.
Thanks again,
Barracuda,
1169 Breezy Point, NY |
Barracuda
| | Posted on Thursday, April 03, 2003 - 2:07 pm: |
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Tech833,
Do you have an opinion on whether there are benefits to be had, and how I might take advantage of them, by being surrounded by water as the posts above indicate?
Thanks,
Barracuda |
Tech833
| | Posted on Friday, April 04, 2003 - 2:10 am: |
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RF travels over salt water almost the same way it does in free-space. There is very little attenuation and phase cancellation over water, and therefore, your signal on the other side of the water would be almost as strong as it would in free-space. Your signal won't start deteriorating until it hits land again.
Sure there is an advantage, if you are trying to communicate to stations on the other side of the water. You get almost the same effect as if you just moved your station to the other side. As far as skip goes, no big difference.
Using the water as a ground plane by electrically coupling to it is the same as if you buried a bunch of radials around the base of your antenna on land. A lower takeoff angle, which would benefit your horizon ERP greatly. |
Barracuda
| | Posted on Friday, April 04, 2003 - 4:48 pm: |
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Tech833,
Once again your help is appreciated. Does the last paragraph mean that I could get similar results by grounding to the water table as I might with a ground plane kit on an antenna like the I Max 2K? Would it be one or the other or would both still be beneficial?
Barracuda |
Tech833
| | Posted on Friday, April 04, 2003 - 11:54 pm: |
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It means that grounding your antenna to the body of water (like if you placed a zinc anode in the water and connected it to your antenna) would produce essentially the same effect as if you buried copper radials around the base of your antenna support structure if you had no water around you. It just improves the capacitivity between your antenna and the ground. |
Ironmask
| | Posted on Saturday, April 05, 2003 - 11:31 am: |
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Tech833
Thank you for your time and patience.
This is what works for me and I feel that it would apply to this conversation.
I have 4 16' lengths of 1/2" copper stranded wire starting at the base of the antenna stretched equidistant away fron the base of the antenna. at the end of each wire is an 8' solid copper ground rod driven down to about a foot below ground level. All 4 legs are connected at the base. There are 2 8' ground rods at the base. To clairify, I use a 45' phone pole for my tower. All radials are connected together as well as to the antenna ground rods. The radials are barried 18" for two reasons 1. The teenager cant ruin the mower and this 2. utilizes the greatest conductivity. Another item. I have a used radiator from a large truck, laid horizontal at a depth of 3' at the base of the antenna. All grounds are connected to each other as well as the radiator. With a I 10K at 43'I show a constant 1:1 SWR. Hope this might help in some way. |
Gunship
| | Posted on Tuesday, August 26, 2003 - 8:56 am: |
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What I would suggest is an extended ground-rod from your tower, at least 8' long. You get down into that water-table good and that's one hech of a groundplane!!! |
Kc0gxz
| | Posted on Thursday, August 28, 2003 - 3:27 am: |
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Barracuda
The I-Max, A-99 and a few other fiberglass antennas use a capacitance grounding method. They do not have a true ground the way that metal ground plane antennas do.
As far as large bodies of water go, they make the best ground plane. Ships have been using them ever since radio communications were first put into them.
During my teens and earlier 20s, I lived on Anna Maria Island just out side of Bradenton Fla. An old Ham who lived a few houses away from me use to take his car down to the beach at nite.
He would wrap a large stainless steel cable around the bumper of his 52 Buick and then throw the rest of it in the Gulf. He told me that he could transmit and receive much farther by doing that.
I was new to CB at that time and I didn't really understand what that crazy Ham was doing or talking about until later in life when I learned about grounding methods and how they work and are applied to radio communications.
Try it yourself sometime and you'll see what a cable dropped into the Gulf of Mexico can really do.
PS: This does not work with the cheap plastic bumpers on todays vehicles.
73s
Jeff, kc0gxz. |
Barracuda
| | Posted on Thursday, August 28, 2003 - 5:56 pm: |
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KC0GXZ,
I recently was checking out an old HeathKit SB-301 Amateur receiver for a friend and experienced first hand the difference a good ground makes on the receive side as well. As stated in some of my posts above I live on a penninsula near the end so my house sits on and is surrounded by beach sand. The water table is about 8' down from grade. I had tried to use a cold water pipe as a ground for the receiver and got absolutely nothing. No static, no nothing. On a hunch, I drove a 10 foot 1/2" copper tube into the sand vertically and tied the ground to that. The receiver now picks up a substantial amount of signal across the bands. A truly dramatic difference. By the way, there was no change in the long wire I was using for the antenna between tests. So 100% of the change had to do with the grounding system!
So grounding is not just for transmit performance.
73
Barracuda |
Kc0gxz
| | Posted on Friday, August 29, 2003 - 2:34 am: |
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Barracuda
You are absolutely right. As you said, grounding makes a big difference in a receiver. If only people realized how many problems could be solved once they ground their equipment. Especially in mobile installations. That's why I have so much hate and discontent for magnetic mounted antennas. However, I guess some people wont or can't drill holes and have to use them.
By the way, that's one of the reasons I miss my home state of Florida so much. It's so easy to drive stakes into the ground. Even through hardpan if needed. Here in Nebraska you need a jackhammer.
A HeathKit SB-301? Wow. Where did he find that one?
73s.
Jeff, kc0gxz. |
Tech808
| | Posted on Friday, August 29, 2003 - 10:45 am: |
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Mag Mount Antenna's
I have never had any problem's with the Wilson's I run.
But then on EVERY Vehicle I have, or installed Antenna's on, I have ran a ground wire from the body or cab or bed or trunk lid direct to the frame.
Even on Body Mount antenna's.
Save's a lot of headaches and takes about 5 minutes time and maybe $1.00 to do it.
I also run all Power Wires, no less than 10ga and most 8 or 6 ga wires direct to Batteries.
Just my 2 cent's worth.
Lon
Tech808 |
Barracuda
| | Posted on Saturday, August 30, 2003 - 5:58 pm: |
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KC0GXZ,
THe SB-301 belongs to a friend, a former HAM. We were talking about radio and he offered to let me check it out for him. It's actually in pretty good shape, but I need to find a manual and maybe schematics.
73
Barracuda |
Monster
| | Posted on Tuesday, November 11, 2003 - 8:28 am: |
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Barracuda
I live in Throggs Neck The Bronx, and am on a penninsula as well. I'm in between two bridges, and in the flight path to LaGuardia. So I pretty much have to keep my base legal (I've had uninvited guests before). Even barefoot I've had amazing results. It really does make a difference |
Gunship
Junior Member
Username: Gunship
Post Number: 26
Registered: 8-2003
| | Posted on Tuesday, June 22, 2004 - 6:21 am: |
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My Dad used to do that at a local resort we used to go to when I was a kid. He had a 56 Chev wagon with a Johnson Blackface and a steel 9' whip on the back bumper. He'd back up to the edge of the water, clamp a wire to the bumper and toss the other end into the lake. He'd sit there and run skip for hours like that. |
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