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Author Topic: To slope a dipole antenna or keep it horizontal? What is recommended?  (Read 5049 times)
K3SFK
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Posts: 4




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« on: April 25, 2011, 09:06:44 AM »

What is the advice of experienced dipole antenna users on this basic MFJ Off Center Fed Dipole for 40-20-10?

The antenna is currently working very well with an ICOM 718 and LDG antenna tuner.  The dipole is 35 feet high at one end and about 20 feet high at the other end.  I have the opportunity to raise the 20 foot end to 35 feet. 

Is this a wise change to make or should I keep the 'slope' or bring the low end up to make the dipole horizontal since the antenna is performing well on all three bands with the current slope arrangement? 

Thank you for your advice and thoughts.

Bill - in Pennsylvania   K3SFK
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WB2WIK
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Posts: 20547




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« Reply #1 on: April 25, 2011, 10:13:35 AM »

I'd raise it.

Until it's very high above ground, every incremental increase in overall height will allow it to work a bit better.  Nothing magical is accomplished by the slope you have.
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K0OD
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Posts: 2532




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« Reply #2 on: April 26, 2011, 07:32:20 AM »

What makes you think it's "working very well" on 20 and 40 meters? Have you tested it in a DX contest? Perhaps for very short skip its OK.  It's probably fine, as is, for ten meters. But is it even clearing houses and trees with some of it at 20 feet?

No dipole that low works at its best. I've always considered about 40 feet (on both ends) to be the minimum for decent performance on those bands. At 50' or more, dipoles can be very good antennas for the higher bands, but with nulls off the ends. 
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WB6BYU
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Posts: 13038




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« Reply #3 on: April 26, 2011, 08:34:00 AM »

Raising it would make only a little difference on 40m, but progressively more on the higher bands.

Would it make a huge difference on any of the band?  Perhaps not, but in general the added
height will be an advantage in almost every case.
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N2EY
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Posts: 3860




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« Reply #4 on: April 26, 2011, 09:20:07 AM »

Raise it.

73 de Jim, N2EY
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K2DC
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Posts: 1346


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« Reply #5 on: April 27, 2011, 09:00:46 AM »

Raise it.  Any opportunity to raise the feed point 7 or 8 feet ought to be taken, and it can only help.

73,

Don, K2DC

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KT4EP
Member

Posts: 15




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« Reply #6 on: May 02, 2011, 07:30:22 AM »

I'd get it horizontal as high as possible.  If you don't like it that way can you move it around and experiment?
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K7KBN
Member

Posts: 2765




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« Reply #7 on: May 02, 2011, 02:12:02 PM »

I'd get it horizontal as high as possible.  If you don't like it that way can you move it around and experiment?

Exactly.  What works in one location might not work the same way just across the street.  It's your station; you can experiment with antennas just about any way you want.
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73
Pat K7KBN
CWO4 USNR Ret.
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