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Yagi better than ground plane??

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Old 02-16-2007, 03:51 AM
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Default Yagi better than ground plane??


I have access to a 3 element yagi (I'm not sure the brand) that I could put up. My question is, would a horizontal 3 element yagi at 30 feet out perform a good ground plane which would be at 40 feet when talking DX.

Also, my yagi and ground plane would share the same mast pipe. How much separation do I need to keep between them? Because I could move the yagi higher up on the mast pipe.

Thanks,
Andy


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Old 02-16-2007, 07:26 AM
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On the flatside, the beam will walk all over the groundplane to a majority of stations in DX.

Good Luck,
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Old 02-16-2007, 08:15 AM
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The main advantage of the beam is due to its directional characteristics, especially on receive. The added gain helps too.

However, there is the exception when the verticle's lower take-off angle will get you someplace that the beam just cannot reach. That's why it's always nice to have them both.
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Old 02-16-2007, 09:09 AM
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Default Re: Yagi better than ground plane??

Quote:
Originally Posted by Andy
I have access to a 3 element yagi (I'm not sure the brand) that I could put up. My question is, would a horizontal 3 element yagi at 30 feet out perform a good ground plane which would be at 40 feet when talking DX.
Yap...at least it should.

Quote:
Originally Posted by Andy
Also, my yagi and ground plane would share the same mast pipe. How much separation do I need to keep between them? Because I could move the yagi higher up on the mast pipe.
I would think 6' min.
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Old 02-16-2007, 10:45 AM
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The answer to the first question is YES......and NO.

A yagi and an omni are two different antennas designed to do two different jobs.

A yagi concentrates the energy in a single direction. At 30' the take-off angle of the signal will be constant and only the changing height of the ionosphere will change where your signal will land. Its like changing the angle of the pool stick when you hit a ball off of a bumper. I'll explain it more if you want.

Also, when a signal skips, it tumbles. Sometimes the receiving station hears you better with a vertical antenna, with you transmitting with a horizontal. And vice-versa.

Today the vertical may work better than the horizontal. The advantage of a beam is that it directs your energy where you want it. The disadvantage is that it has to be rotated.

If you are interested in DX, get a beam. If you want to talk to locals and the occasional DX, get a vertical.

As far as separation goes, my number is 14.5' It is a non-resonant distance of a 1/4 wave while still being shorter than a 1/2 wave. This is theory and has worked for me. Half this distance would be 7'-3" and should work also.

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Old 02-16-2007, 04:43 PM
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Quote:
Originally Posted by Master Chief
The answer to the first question is YES......and NO.

A yagi and an omni are two different antennas designed to do two different jobs.

A yagi concentrates the energy in a single direction. At 30' the take-off angle of the signal will be constant and only the changing height of the ionosphere will change where your signal will land. Its like changing the angle of the pool stick when you hit a ball off of a bumper. I'll explain it more if you want.

Also, when a signal skips, it tumbles. Sometimes the receiving station hears you better with a vertical antenna, with you transmitting with a horizontal. And vice-versa.

Today the vertical may work better than the horizontal. The advantage of a beam is that it directs your energy where you want it. The disadvantage is that it has to be rotated.

If you are interested in DX, get a beam. If you want to talk to locals and the occasional DX, get a vertical.

As far as separation goes, my number is 14.5' It is a non-resonant distance of a 1/4 wave while still being shorter than a 1/2 wave. This is theory and has worked for me. Half this distance would be 7'-3" and should work also.

Thanks for your help and info.

I don't know if this makes a difference but... I just found out that the yagi is a 4 element not a 3 element.

I do plan on keeping my omni up. I was just wondering if it would be worth my time putting a 4 element (horizontal) yagi up. I am mostly interested in talking DX, for everything else I would use my ground plan. What's your opinion (is it worth my time)? I have the antenna and the rotor, I just didn't want to put something on the tower that really isn't going to be that much help.



Thanks for your time and patience.

Andy

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Old 02-16-2007, 05:40 PM
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Definitely worth it. A 4 element Yagi is a DX machine, for sure.
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Old 02-16-2007, 11:38 PM
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Its worth it. See here for info on the 4-element:
http://signalengineering.com/ultimat...ment_yagi.html

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