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W6OGC
12-04-2011, 09:12 PM
I have been planning to put up a loop, around the eaves of the house in this small lot, HOA restricted neighborhood. The dimensions of the house are about 30' wide and 65' deep. The resulting loop would be close to 200' around.

The house is two story, and the roof line, and eaves are not in a straight line, in the horizontal plane. The roof peaks across the front. Along each side, the roof line goes straight back horizontally, then takes an upward path for a ways before descending to the rear, across which is is a straight horizontal run. IOW, across the front, it is a wide inverted "V", across the sides it is some of both, an inverted "V" and a straight line, and across the back it is straight.

Must the loop be strung in a straight horizontal plane, or can it follow this irregular roof line? Any theory or modelling as to which would be best, or would it matter?

WA4OTD
12-04-2011, 09:38 PM
I put up a loop for 160M around the inside of my attic and it is around 45 feet up. I have been able to contact 45 states, but very few DX and mostly it is good close in. Someone said horizontal loop is better for close in and that matched my performance. I was not terribly impressed with it, but I like you live in HOA restricted neighborhood so I do the best I can and try different things. It did work on 80M when I cut open the loop so it was an 80M horizontal U, but again not that impressive. Best is to just try it.

KC8VWM
12-04-2011, 09:44 PM
You mean like this one?

80158

The article is posted here:

http://www.eham.net/articles/22237

K5RCD
12-04-2011, 09:53 PM
http://k5rcd.org/hor loop instruct.htm

W6OGC
12-04-2011, 10:01 PM
Thanks Randy, I had seen your most informative site in another thread.

Do you have any thoughts on keeping the wire in the same plane?

I am also trying to figure out the best way of attaching the wire to the eaves. I am thinking of attaching short lengths of small PVC tubing to the eaves then running the wire through all of them.

I'll tune this loop with a AH-4 which I have now in service tuning a 47' wire. It seems to have adequate range, and Icom claims it will match anything >23' 80-6M.

K5RCD
12-05-2011, 01:11 AM
In theory, it is best to keep the wire on the same plane, but in reality I don't think it makes that much difference in the long run. Most hams putting up loops have to make sacrifices of one kind or another. I think the most important factors are getting as much wire in the air as possible (overall length), and enclosing the largest area you can under the circumstances.

The PVC standoffs work really well. A number of hams have contacted me using a loop around the perimeter of their house with good success, and most are happy with the PVC.

The AH-4 should work well for you. It should tune 40 through 6 meters quite well with the loop. You can mount that tuner at the antenna feed point and run coax to you rig without suffering major losses on non resonant frequencies. I think you will be pleasantly surprised with the results.

Good luck with your project.

WB2WIK
12-05-2011, 01:14 AM
I think so, too. It shouldn't matter much if the wire is all horizontal or running in various directions.

What's more important is the dielectric properties of the house it's right next to.

W6OGC
12-05-2011, 01:38 AM
In theory, it is best to keep the wire on the same plane, but in reality I don't think it makes that much difference in the long run. Most hams putting up loops have to make sacrifices of one kind or another. I think the most important factors are getting as much wire in the air as possible (overall length), and enclosing the largest area you can under the circumstances.

The PVC standoffs work really well. A number of hams have contacted me using a loop around the perimeter of their house with good success, and most are happy with the PVC.

The AH-4 should work well for you. It should tune 40 through 6 meters quite well with the loop. You can mount that tuner at the antenna feed point and run coax to you rig without suffering major losses on non resonant frequencies. I think you will be pleasantly surprised with the results.

Good luck with your project.

Thanks. I've been using the AH-4 on the inverted U random wire and have been surprised with how it works, once I got the hang of it. Of course, this wire strung across the balcony is not going to be a terrific antenna by any stretch of imagination but I have worked Europe and the Far East, and all over NA in the short time I have had it up, with the inevitable de-bugging. It is more mediocre on 40 and 80, although the tuner matches it.... as expected.

I intend to run the wire around the house in some fashion, from the top of the AH-4 around to the bottom, no feedline other than to the AH-4.

Any idea if having the ~91' counterpoise still attached will help, or hinder performance?

KI6USW
12-05-2011, 02:25 AM
A DX antenna?
Or no?

W6OGC
12-05-2011, 04:39 AM
A DX antenna?
Or no?

Well, one can always hope, I guess.

It would be wonderful if there was some good solid propagation advantages I could count on and plan for but reality is that in this small, HOA restricted site, the choices are very few.

I have plotted and schemed for quite a while; this seems to be the best choice from the standpoint that it can be done, while other more ambitious options probably cannot. One outcome I want to avoid if possible is spending a lot of money and effort to end up with something that doesn't work very well.

For example, my first best hope was a 43' vertical, but there is no room to mount it or run radials. Mounting it on the roof would cause HOA concerns, and the roof is red tile, very difficult to work on without breaking lots of tiles. Next, a 33' vertical out on my dock.... using the salt water below for counterpoise......... mechanically challenging if even doable, but a terrific experiment. With the sailboats at adjacent docks, etc. the coupling possibilities would be daunting to deal with.

This loop won't likely be the best antenna imaginable, but it may be the best I can do.

KC8VWM
12-05-2011, 05:25 AM
A DX antenna?
Or no?

I don't know what "hope" has to do with antenna engineering and design...

My answer is no because it doesn't have the required wavelength height above ground to achieve this.

K9ZMD
12-05-2011, 07:16 AM
At that low height, some performance is what you can hope for, not optimum performance. Planes and angles become irrelevant. Instead, go for max wire length & enclosed area.

Antennas around the perimeter of a house have some disadvantages. They are too low for any reasonable expectation of DX contacts, or even loads of contacts within the US. They are so close to all the domestic electronic devices and wiring, that your receive noise level may be frustratingly high. On a positive note, propagation is king so you may be very surprised by some of the contacts you are occasionally able to make, and a good noise canceling device (think MFJ) may remarkably improve that noise level for you.

Insulators intended for electric fences come in many shapes and sizes. I used some small, plastic fence insulators for the last antenna that I installed under the eaves of a house. Those insulators were not expensive, and worked better than anything I could have fabricated. I used this "invisible" antenna for a few months while we were renting. In spite of the high noise level, I was able to make quite a number of contacts, notably all US call districts (a clean sweep) during the SKCC's January K3Y anniversary event.

N0AZZ
12-05-2011, 09:27 AM
All I can give is an example of my 160m loop full wave it was coax fed at one corner with a balun. It was at different heights from 55'/48'/31'/24' not good but it was at least in the clear for the most part. It was the best antenna I have used for all of N. America to the N. end of S. America usually S9 signals and 5/9 reports worked a little DX with it but not a lot. It would tune and load nicely on all bands 6-160m and I ran QRP to QRO on it. On your loop I wonder how much of a problem might be caused by the house wiring is all and the size.

The only thing I can think of for you another choice for an antenna would be a Flagpole they are very nice and work well in areas like yours. In the front yard you could lay as many ground radials as possible to what ever lengths possible using staples they don't have to be straight. The small box at the bottom is easily concealed from view with a small bush or flowers and never seen. If you haven't checked them out you might do so.

W6OGC
12-05-2011, 07:34 PM
I don't know what "hope" has to do with antenna engineering and design...

My answer is no because it doesn't have the required wavelength height above ground to achieve this.

The Old Timer always taught to "take from no man his dream!"

It is true that this will not be pile up buster. With such a modest antenna and running 100 watts, I will have to work hard for everything I can get, pick my shots. It won't be like the old days, 30 years ago when I was sitting there with my C Line, L4B and 4/4/5 el quad at 66', picking 'em off at my leisure. But it will have to do for now, and hopefully will be an improvement over the present recently erected inverted "U" strung across the balcony. In thsi situation you want to eliminate every source of inefficiency possible, and put it up so as to get the most out of it.

That said, even at less than ideal heights, I'm close to the ocean, no obstructions in any direction, and will have my successes, considering.

WB2WIK
12-05-2011, 07:39 PM
The Old Timer always taught to "take from no man his dream!"

It is true that this will not be pile up buster. With such a modest antenna and running 100 watts, I will have to work hard for everything I can get, pick my shots. It won't be like the old days, 30 years ago when I was sitting there with my C Line, L4B and 4/4/5 el quad at 66', picking 'em off at my leisure. But it will have to do for now, and hopefully will be an improvement over the present recently erected inverted "U" strung across the balcony. In thsi situation you want to eliminate every source of inefficiency possible, and put it up so as to get the most out of it.

That said, even at less than ideal heights, I'm close to the ocean, no obstructions in any direction, and will have my successes, considering.

Being next to the ocean and being retired both offer great benefits when it comes to working DX, or really working anything. You can pick when you want to operate, which would be very high on my list of important stuff if DXing was my goal.

W6OGC
12-05-2011, 07:42 PM
The only thing I can think of for you another choice for an antenna would be a Flagpole they are very nice and work well in areas like yours. In the front yard you could lay as many ground radials as possible to what ever lengths possible using staples they don't have to be straight. The small box at the bottom is easily concealed from view with a small bush or flowers and never seen. If you haven't checked them out you might do so.

I live in a marina enclave in San Diego Bay, very small lots, 40x110 or so, and no front yard worthy of the name. I have HOA approval for a vertical antenna, but mechanically it has been very difficult to plan. It would only fit on the roof which is red tiles, and mounting and guying is problematic. I've spent a lot of time trying to figure out how to put a vertical on the dock, which sits on sea water, but that has its own issues. That is why I finally put up the end fed inverted "U" which has been surprisingly OK...... considering how modest it is.

The good news is that I am retiring soon and plan to move to Texas on some acreage! :D

KC8VWM
12-05-2011, 08:10 PM
Yeah maybe you're right... I am just thinking of any possible way to make it work out for the best in your situation. But couldn't you just lay a fan dipole up there instead? It's just that end feds require a special diet and they can be problematic. I would rather see your RF charging up the ionosphere instead of being wasted to modulate the elements in your toaster oven. :) Balanced antennas, folded dipoles or even a set of closed loops laying on the roof might be a better option for consideration especially if operating anything more than QRP power is in the cards. I know living in an HOA has it's challenges, but end feds are notorious for creating issues with the locals especially at higher power levels. Closed loops will provide an advantage in terms of lowering noise levels in your reciever wheras an end fed is going to pick up anything and everything, especially if it's not up in the clear and is located in close proximity to your house.

My Best,

AA5ET
12-05-2011, 11:41 PM
I've been using horizontal loops for more than ten years; ever since David Fischer (W7FB) talked me into it - he even offered to help put it up. David wrote the "Skywire Loop" QST article on it back in the 1980s. I think your plan will work okay. If the feed length is less than 30 feet or so feed it with coax, otherwise use some type of parallel feed to reduce losses.

Here's a link to the article: http://srgproperties.inetusanow.net/files_custom/9467_2192.pdf

W6OGC
12-06-2011, 04:20 AM
I've been using horizontal loops for more than ten years; ever since David Fischer (W7FB) talked me into it - he even offered to help put it up. David wrote the "Skywire Loop" QST article on it back in the 1980s. I think your plan will work okay. If the feed length is less than 30 feet or so feed it with coax, otherwise use some type of parallel feed to reduce losses.

Here's a link to the article: http://srgproperties.inetusanow.net/files_custom/9467_2192.pdf

Thanks for that link. I vaguely remember that from 25 years ago. It's funny how some articles have stuck in your mind. I see articles from QST from back in the '50's and remember how I poured over them with such fascination.

N0AZZ
12-06-2011, 01:50 PM
Wow what a vertical if you could put one up with a single ground wire ran to the sea water it doesn't get much better than that.

Good luck on whatever your able to end up with.

Good DX

W6OGC
12-06-2011, 06:30 PM
Wow what a vertical if you could put one up with a single ground wire ran to the sea water it doesn't get much better than that.

Good luck on whatever your able to end up with.

Good DX

I've been discussing this with several prolific antenna experts, and it is tantalizing, in theory anyway. I would want a 33' vertical out on the end of the dock, with a very large possibly copper tube into the water a couple of feet.

In practice, the vertical would be within close distances of sailboats and other craft, coming and going, the tide raising and lowering...... it is predictable that the characteristics would be constantly changing in unpredictable ways.

Corrosion, the sea water eating up the metal therein... constant maintenance.... just getting the vertical mounted mechanically on a dock about 6-7' wide..... present lots of questions about how this would work in practice.

KI6USW
12-06-2011, 07:11 PM
Sounds like the benefits outweigh the shortcomings to me.
Use brass bolts/screws for mounting. The rest sounds easy enough to do. Most guys would like to have a ground field like the one you have. IE: 'salt water'.
:cool:

N0AZZ
12-07-2011, 11:35 AM
Can you ground mount the antenna then run a copper braid or wire to the edge of the water then a 8' ground rod then run a strap to the water from it?

W6OGC
12-07-2011, 06:52 PM
Can you ground mount the antenna then run a copper braid or wire to the edge of the water then a 8' ground rod then run a strap to the water from it?

The bay is tidal, from -1.5 or so to +7.2 or so, a nearly 9 vertical feet difference. The sea wall at the back is vertical. We have a dock that floats with the tide, held in place by concrete piers sunk into the channel floor. Mounting the antenna at the seawall, means the "ground" wire, or plate, is exposed or not depending on the tide, unless it floats too. Copper doesn't float very well, I'm told.

What I have been told, by antenna pros who write articles that the rest of us can barely read, is that a cylinder about 18" in the water would be optimum. The antenna mounted on the dock, with ground strap to the cylinder fixed to the dock is what I have been thinking about. That presents guying or mounting problems I haven't figured out yet. Mechanics and structure is not my strong suite.

Maybe what I need to think about is a large copper plate, fixed to the bottom of a chunk of Styrofoam or similar, so it is underwater, floating in the bay, with ground strap up to the lot to attach to the antenna sitting on the seawall.

The other issue these experts identified was the coupling to the metal masts of sail and other boats, which are tied up nearby, but sometimes not. That would cause unpredictable variations in loading characteristics, they predict.

Hmmmm.

KC8VWM
12-07-2011, 06:58 PM
Automobile radiator filled with sand.

K8JD
12-07-2011, 11:55 PM
A 33 ft vertical over seawater would be a GREAT DX ant on 40M, you can bury some kinds of coax to get back to the house.

KF4OKF
12-08-2011, 02:26 AM
I just put up a loop antenna in my backyard for 160m using a lot of information by Randy Davis, K5RCD. While your antenna may not be a Yagi at 100 ft. I bet you will make a lot of contacts with it. You might consider using ladder line and a tuner for multi band operation as recommended by Randy Davis. Loops are quiet antennas and I am amazed at how I can hear stations with the loop. Ladder line has low loss at HF frequencies and is fairly easy to work with. I also used a GAP Eagle vertical at my QTH in Florida which is close to the ocean and it worked great. Since you have permission to put up a vertical you might take a look at verticals.

73,
Tory
KF4OKF