Posted by
Eugene Worth on
Apr 11, 2005; 5:34pm
URL: http://elecraft.85.s1.nabble.com/Non-resonant-attic-loop-tp376882p376885.html
Good points, Bob. And ... errrrrrrrrrr ... no, not exactly .... I know
it is 20+ feet above the ground, so far so good. We are moving 500 miles
from our present QTH, and I didn't have a ladder to get to the attic
opening when we were shopping for a house. I do know that outside, I'll
have a flagpole antenna ... maybe a short wire, but it will have to be
modest.
The attic length less than 44 feet, that I do know, so the non-resonant
dipole isn't a great choice, unless I let the ends droop a bit. I do
have a "slinky" dipole that may find its way into the house attic or the
garage attic (12-15 feet AGL).
I know that part of the house has cathedral ceilings on the upper floor,
so I'll just have to have a look and see if I can snake some wire over
that area and keep it clear of electrical stuff.
I just wondered if there was a magic number for a non-resonant loop. My
thinking is that I could get enough wire up there for a 40-meter loop.
And, even if I had to double back in places, it would still work
reasonably well. I'll probably feed it with ladderline b/c it will be
non-resonant at a number of the frequencies I plan to work. Then, let
the tuner take care of the rest.
73, gene KC0RXY
Robert Tellefsen wrote:
> Gene
> Can you tell us what linear dimensions your attic would have
> for potential dipoles?
> They also work at nonresonant lengths, and work quite well.
>
> At frequencies above their resonant length they can actually
> contribute some gain. Height above ground will be a bigger
> factor, in that for freqs below the resonant freq, you will
> find your major lobe pretty much straight up. But it will
> be a fat lob, and work out to a distance as well, just not
> as well as a dipole up over a quarterwavelength on the band
> in use.
>
> 73, Bob N6WG
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