K9LTN spent a huge amount of money to build a frame with six SteppIR
antennas that could tilted to change the radiation angle and it also
rotated. As far as I know this system never worked.
John KK9A
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fwd: Stacking question - another reality data
point
From: "Joe Subich, W4TV" <lists@subich.com>
Date: Thu, 11 Aug 2016 15:35:03 -0400
Lawson's (W2PV) work included attempts to optimize RF at preferred
take off angles by physically tilting the boom of HF antennas. His
results mirrored that of attempting to do "beam steering" - there
was little difference in elevation pattern with small amounts of
tilt (up to 30 degrees or so) with larger amounts of tilt the peak
gain fell off significantly and the nulls became less pronounced.
In general, with stacks of two or four antennas one can achieve the
maximum practical benefit by simply running one (for a pair) or two
(for four) antennas out of phase. Try modeling four 24' to 36' boom
6 or 10 meter yagis at 1, 2, 3, 4 wavelengths (evenly spaced) above
ground with all in phase, top two out of phase, middle two out of
phase and 1st/3rd antenna out of phase to see what I'm talking about.
73,
... Joe, W4TV
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|