[TowerTalk] 80 m delta loop

[K4SAV]

An addition to my antennas comparison post.

I compared an equilateral delta to an inverted vee.  If you flatten the 
shape of the delta some to get the bottom wire higher, you can pick up a 
little more gain. Maybe make the sloping wires about 63% of the bottom 
one, and feed it about 25% up one of the sloping sides. When you do 
that, at the same height as the inverted vee it gives 3 to 6 dB more 
gain than the inverted vee between the elevation angles of 5 to 11 
degrees.  The break even point becomes 18 degrees elevation, and after 
that the inverted vee wins big time again.

So whether this is a better antenna for DX, or not, now depends on how 
much DX you think arrives below 18 degrees elevation on 80 meters.

Jerry, K4SAV

>Randy Lake wrote:
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>>So if one was to have the choice of an inv.v at 95' or a delta hung from 
>>the same support which would be the best choice for dx?
>>73, Randy N1KWF
>>
>>
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>>
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K4SAV wrote

>Here is a comparison between an inverted vee, apex at 95 ft with an 
>included angle of 120 degrees, compared to an equilateral delta loop 
>with apex at 95 feet (which makes the bottom wire at 9 feet) and fed at 
>the bottom corner. Broadside to the antennas, the delta only has 1 to 2 
>dB advantage for very low angles (less than about 7 degrees).  The 
>break-even point is 11 degrees elevation.  Above 11 degrees, the 
>inverted vee wins big time. Off the ends of the antennas, the delta 
>loop, in the direction opposite from where it is fed, has a little more 
>gain than the inverted vee off its ends. I think the inverted vee is a 
>hands-down winner, for all purposes, when the choice is between these two.
>
>Note: An inverted vee with an included angle of 90 degrees loses about 
>0.6 dB compared to one with 120 degree angle, but it gets the advantage 
>back when looking at the gain off the ends of the vee.
>
>There are some other choices of shapes that I think will beat an 
>inverted vee at 95 feet for DX, such as a rectangular loop (100 ft x 45 
>ft) fed on the side, but these are hard to support from a single tower, 
>and so, may not be a fair comparison. You didn't ask for comparison to 
>other choices.
>
>Jerry, K4SAV
>
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