HF Dipole Antennas: Why Horizontal?

SSTJ

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Saw on another thread that @Jerry Bransford is installing a dipole antenna in his attic. I was just reading about dipole antennas and had this question:

For HF, why is it that horizontal dipoles are so popular? I can understand the ease of installation vs a vertical arrangement, but I would think that vertical would have a more omnidirectional signal, whereas horizontal would probably broadcast stronger in directions perpendicular to the antenna, but not as strongly in directions parallel to the antenna. No?

Or are horizontal dipoles so common in HF that you need to use one in order for your signal's polarization to match that of other stations?
 
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SSTJ

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@Jerry Bransford, I'm also eager to hear how your experience goes with the antenna in the attic. I have no HOA, so could do something outside, but I also have a very large attic. Wife (and probably some neighbors) would prefer if I did it inside, but I wonder how much that will interfere with things.
 

Jerry Bransford

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@Jerry Bransford, I'm also eager to hear how your experience goes with the antenna in the attic. I have no HOA, so could do something outside, but I also have a very large attic. Wife (and probably some neighbors) would prefer if I did it inside, but I wonder how much that will interfere with things.
My first HF antenna was a 10m dipole placed inside my attic when I still lived near San Diego and I worked DX around the world with it. Europe, Pitcairn Island, Vladivostok Russia, Japan, all over Europe, South Pacific, etc. I probably worked 25 countries with it so even though it was inside my attic it worked very well. That was a huge attic which made it easy to install, I wish I had a similar attic now lol. So if you have a non-metallic roof you should be fine. Just keep as far away as possible from anything like steel heater or a/c ducting.
 
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OldBuzzard

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HF is mostly used for DX (distance) by bouncing a signal off the ionosphere. That bounce twists the polarization around, so any polarization of antenna should work equally well. It's true that a vertical will have a more omnidirectional pattern, but at a lower signal strength. A horizontal dipole will be more directional, which can be an advantage. For instance, I'm in the middle of the US, so I use a horizontal dipole with the lobes pointing east and west, to get good coverage of the US. That also works well for other countries in those directions, but not as well for, say, Russia or South America. Another advantage of the horizontal is that it will fit in an attic, and may be easier to erect on an expedition, depending on the antenna style. Mobile antennas usually must be vertical. Everything is a compromise with HF antennas. You do what you can with the space you have, since these tend to be big or gigantic antennas.
 
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SSTJ

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My first HF antenna was a 10m dipole placed inside my attic when I still lived near San Diego and I worked DX around the world with it. Europe, Pitcairn Island, Vladivostok Russia, Japan, all over Europe, South Pacific, etc. I probably worked 25 countries with it so even though it was inside my attic it worked very well. That was a huge attic which made it easy to install, I wish I had a similar attic now lol. So if you have a non-metallic roof you should be fine. Just keep as far away as possible from anything like steel heater or a/c ducting.

Awesome, I'm excited to hear this.
 
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SSTJ

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HF is mostly used for DX (distance) by bouncing a signal off the ionosphere. That bounce twists the polarization around, so any polarization of antenna should work equally well. It's true that a vertical will have a more omnidirectional pattern, but at a lower signal strength. A horizontal dipole will be more directional, which can be an advantage. For instance, I'm in the middle of the US, so I use a horizontal dipole with the lobes pointing east and west, to get good coverage of the US. That also works well for other countries in those directions, but not as well for, say, Russia or South America. Another advantage of the horizontal is that it will fit in an attic, and may be easier to erect on an expedition, depending on the antenna style. Mobile antennas usually must be vertical. Everything is a compromise with HF antennas. You do what you can with the space you have, since these tend to be big or gigantic antennas.

Nice, thanks. Very helpful.

I'm in SC, so I guess I'll see what I can do to get my lobes oriented ideally. (Lobes are perpendicular to the antenna length, right?)

But of course my attic configuration may make that decision for me.
 

OldBuzzard

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I'm in SC, so I guess I'll see what I can do to get my lobes oriented ideally. (Lobes are perpendicular to the antenna length, right?)

But of course my attic configuration may make that decision for me.
Yes, perpendicular. For a simple single-wire dipole, the lobes are quite wide, so you'll get a lot of signal in a big spread of directions (think fat bow tie pattern).
 
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KingCarGuyZ

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The simple answer is bouncing of the ionosphere and the "nulls" on that long of a wavelength are not very sharp. It's much easier to put up a horizontal antenna than a vertical, but either will work.

As I have been told time and time gain in radio - Everything works, just some things work better.
 
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OldBuzzard

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As I have been told time and time gain in radio - Everything works, just some things work better.

Ahh, yes, I had forgotten that adage. Will a 1/2 inch antenna work on HF? Yes, people have used the filament in the lightbulb as an antenna. Does it work very well? Sure, if the person you're talking to is a few feet away. ;) In other words, No. A half-wave dipole works a LOT better.