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Old April 22nd 04, 01:20 AM
zeno
 
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The problem, as I see it, with using the fixed masts as outside perimeter
configuration support structure for the specifically ordered interior shape is the
sag the inevitably occurs when wire is a rope and pulley distance away from the
supporting mast. I already see this with the tree supported antenna. The ropes drop
down and the wire is 8' or so lower than anticipated. This seems critical when the
masts are only 50' to begin with. How high, or shouls I say, what is the minimum
height for an acceptable Rhombic?

Bill, K6TAJ

Richard Clark wrote:

On Wed, 21 Apr 2004 20:47:47 GMT, zeno wrote:
Although I have the acres (7) there are a lot of buildings (old barns etc.),
trees, etc. My antenna planning has to dodge many many obstacles actually. This
is an old chicken ranch and there are building everywhere, then all the trees.
Are you saying that a rhombic could be put up on the same masts more or less
(only one of the masts is potentially moveable, meaning that it would only be
diamond like at one end of the trapezoid. This rhombic would be instead of the
540' loop?

I will look up rhombic in the books and see what gives.


Hi Bill,

No, this time shape matters as it is a function of all angles of
radiation combining to ADD rather than jumble. Again, think in terms
of the supports/mast merely being the outer, irregular perimeter to an
ordered interior antenna shape.

The Rhombic would BE the 540' loop. Normally it is open or terminated
at the end opposite the feed point, but having the shape anticipated
is more the work than this simple change. (It has the same feed
considerations, complete with your expected twin lead.)

Congrats on your desired call.

73's
Richard Clark, KB7QHC


 
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