[Towertalk] Sloping Dipoles Square Array

jljarvis jljarvis@abs.adelphia.net
Tue, 19 Mar 2002 07:27:11 -0500


Thanks to all who provided the YCCC link for spitfire 
array info.  Turns out to be mis-identified by me.

What I'm contemplating is the K8UR Sloping Dipoles Square Array,
as described by ON4UN, in Low Band DXing,(1999), page 11-77 et. seq. 

In this case, full sized dipoles are sloped down from the tower,
to the feedpoint/midpoint, and then fold back toward the tower base.
They reach the tower a couple of meters above ground.

I was initially contemplating this for 40, in lieu of a rotary.
90 degree half power beamwidth, 4.3dBd gain @ 15 degrees elevation,
in the 80m model provided in the book.  Compares favorably with
2 el yagi numbers, for the 75', low-load installation.  The
tower is mil-surplus, permitting install-deinstall in less than a day.
Consequently, can be easily moved to another site.  

Upon reflection, I now realize that it may be possible to implement
this on 75/80, with what I'm planning.  Structural issues will gate 
the project, for the next few weeks, so I'm going to shelve the 40m/80m 
solutions decision for a bit.

Meantime, I'm off to model stacked LPDA's vs. hamband dedicated yagis,
while I work on the tower rotation challenge.  

Thanks, all, for your help. 

N2EA