[TowerTalk] PARASLEEVE ANTENNA ELEMENTS

[spelunk.sueno]

     Here's an idea:  Use parasleeve-like DEs for a 3L array on 5 bands by
mounting the last two sleeves (for 17 and 12) ABOVE AND BELOW the other
three, using the mast for a support.  Sort of like very close-spaced dipoles
on all bands.  This requires that the array be mounted with the DEs at
approximately the mast location (hence the need for 3Ls; the Directors would
have to balance array.)

     This isn't as far-fetched as it may seem (I hope).  Look at Tom's 3/2
Zagi array at http://www.qth.com/force12/  .  The DE for the 80M Yagi is
above the Refl and Dir.  The whole array "thinks" it's at 88 feet, the
elevation of the DE.

     To make this into a 2L array for 5 bands you'd need some way of
mounting the last two elements in a vertical plane, co-planar with one of
the boom-mounted parasleeves.  Or can you get away with simply mounting the
5 sleeves in the same horizontal plane, with two elements very far from the
(presumed) central split dipole and two adjacent to it?  My suggested
arrangement keeps the solid sleeves in proximity to the split dipole, albeit
in 3 dimensions.


Gene Smar  AD3F
spelunk.sueno@mci2000.com

P.S. Dibs on royalties!
-----Original Message-----
From: T A RUSSELL <n4kg@juno.com>
To: TOWERTALK@contesting.com <TOWERTALK@contesting.com>
Date: Monday, January 25, 1999 10:46 AM
Subject: [TowerTalk] PARASLEEVE ANTENNA ELEMENTS


>
>PARASLEEVE   ANTENNA   ELEMENTS
>
>Parasleeve  antenna elements refers to a means of using
>multiple parallel coupled elements to achieve multiple
>resonances without the use of traps or stubs.
>
>Generally, the longest element (lowest frequency) is
>chosen as the directly fed element and higher frequency
>elements are added parallel to the main element.  Coupling
>(spacing) is adjusted to provide a second (and third) match
>on the desired higher frequencies.
>
>This is the technique that allows the Force 12 antennas to
>provide 3 full size driven elements without traps and only one
>feedline in their C3 series of antennas.  A continuous 15M
>parasleeve element is placed behind the 20M split dipole
>and a continuous 10M parasleeve element is placed in front
>of the 20M driven element.
>
>One disadvantage of parasleeve elements is that the coupling,
>and therefore SWR, changes when the elements vibrate out of
>their normal resting position, such as when the wind blows.
>Some sort of insulated spacer may help to reduce this effect.
>
>There was an acticle in QST describing a parasleeve vertical
>for 40, 20, 15, 10 meters, configured in a square pattern.
>
>I am not aware of anyone making a 5 band parasleeve
>driven element yet, but that would seem to be an ideal
>means to cover 20, 17, 15, 12, 10 meters combined with
>separate reflectors for each band, spaced at 0.15 WL or so.
>
>Would the first commercial manufacturer of this idea please
>send me a "sample" for evaluation?  :-)
>
>de   Tom   N4KG
>
>
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