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Author Topic: Dipole orientation  (Read 2657 times)
K3WEC
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Posts: 260




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« on: September 07, 2012, 05:38:49 PM »

What effect will positioning a dipole (Vee) in a "bent" fashion have?   By "bent" I mean that the wire ends terminate at positions not in line with the apex.   If one were to view the arrangement from above, one would see a V shape in the horizontal.
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W8JI
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« Reply #1 on: September 07, 2012, 06:05:15 PM »

What effect will positioning a dipole (Vee) in a "bent" fashion have?   By "bent" I mean that the wire ends terminate at positions not in line with the apex.   If one were to view the arrangement from above, one would see a V shape in the horizontal.

As odd as it seems, the effect is almost the same as rotating the antenna slightly to a new line that is equal angles to each side.

In other words, if you V the dipole in a 90 degree bend, it is almost like having it on a line 45 degrees off from each leg. It loses a littkle end null as the bend approches 90 degrees, and goes to heck at an increasing rate as it is bent more, but for bends much under a 90 it is almost exactly like just rotating it a little bit.

Right off the point, or in the back away from the point, is the maximum. That maximum is only a little less than a straight dipole would be.
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K3WEC
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« Reply #2 on: September 07, 2012, 06:36:35 PM »

Thank you, does the same result occur with a Windom oriented similarly?
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K5LXP
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« Reply #3 on: September 07, 2012, 08:04:15 PM »

What band, and how high up is it?  Height also influences the pattern.  Are these single or multiband antennas?


Mark K5LXP
Albuquerque, NM
« Last Edit: September 07, 2012, 08:35:45 PM by K5LXP » Logged
WB6BYU
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« Reply #4 on: September 07, 2012, 09:00:20 PM »

A Windom on its fundamental will act the same as a dipole - they are essentially
the same thing.

On higher harmonics the pattern will be different, and will depend on how many
wavelengths long the antenna is, height above ground, and the amount of bend.
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K3WEC
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Posts: 260




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« Reply #5 on: September 08, 2012, 11:09:04 AM »

What band, and how high up is it?  Height also influences the pattern.  Are these single or multiband antennas?


Mark K5LXP
Albuquerque, NM

The antenna doesn't exist yet.  I'm planning it now given the lot constraints I have.   I would like a multiband, 80-20.    Height will be at most 35 ft above ground at the apex.
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W8JI
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« Reply #6 on: September 08, 2012, 02:51:07 PM »

Off-center feed will not have the pattern of a dipole on harmonics, and also a bent dipole with multiple wavelength legs does not have the same effect as a half-wave dipole.
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W5WSS
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« Reply #7 on: September 10, 2012, 06:50:32 AM »

There is reference to the horizontally oriented dipole antenna where an 90 degree apex is formed and where the feed point is located at the apex. The antenna is used as a transmitting antenna on shortwave.
Google The Quadrant antenna. I have built one and installed it indoors on my ceiling fed with open wire line and pressed into multi band service.
I can not comment further on the pattern as mine was indoors and coupling to other conductors deems any specific behavior a question of interaction.
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KQ6Q
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« Reply #8 on: September 11, 2012, 02:08:19 PM »

I had a vee'd dipole years back - the feedpoint was on the edge of the roof of a 3 story building, the ends were tied off at stairwells extending out from the same side of the building. The resulting vee was about 135 degrees both vertically and horizontally. The length was 3/2 wave overall, fed with RG-11. It was broadly directional off the ends of the wires. I was very happy with the results.
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