Dink,
The articles on half squares and grounded half squares do have two identical
antennas at right angles to each other. But as you mention having the
towers could cause a problem although K4DLI has his rounded half loop only a
few feet away from his 70 foot tower. See a recent NCJ for a description.
Another possibility is to use the actual towers as a grounded half loop for
160 if you can get 130 to 135 feet between the two. The 160 grounded loop
will also work on 80/75 and other bands. The grounded half loop is a pet of
Dr. Dave Fischer W7FB (ex W0MHS) or Dr. Loop Skywire. K4TEA has his design
with 32 radials at each end and a wire back to connect the two radial
fields. You feed this at the base. You would probably need to detune the
base so it appears to be off the ground on the
feed point end.
73 Dave K4JRB
----- Original Message -----
From: "Michael Dinkelman" <mwdink@eskimo.com>
To: "Towertalk" <towertalk@contesting.com>
Sent: Sunday, October 11, 2009 12:36 AM
Subject: [TowerTalk] Half-Square Guidance
> Hello All
>
> So, between my two towers, it appears I may have enough room
> to put up a half-square for 80 meters. I've read the info in the
> antenna book but still have a couple of questions that weren't
> really addressed there. Rather than waste some valuable time,
> maybe others have addressed them.
>
> 1) As I said, the two supports would be 60+ foot towers. As such,
> the vertical portions would parallel the towers. I expect that might be
> a problem. (I wouldn't normally try to put a vertical next to another
> metal structure and a half square is essentially two phased verticals.)
> I could make the verticals slant away from the tower. The literature
> indicates that shouldn't have much effect on performance but I'm not
> sure it would prevent the tower from affecting the antenna.
>
> 2) Providing the above isn't an issue, can I use one tower as the apex
> of two separate half-squares? (see below) One going in one direction
> and another maybe 90 degrees off? (That would seem to be a problem
> as the two would be resonant at the same frequencies and I see
> coupling issues.)
>
> O---------------------O
> O
> |
> |
> |
> |
> O
>
> cheers
> dink, n7wa
>
>
> _______________________________________________
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