Re: [CQ-Contest] Be careful

[Bill Tippett <btippett@alum.mit.edu>]

K3BU:
>Just to bring to attention that verticals can be awesom, beat Yagis when
properly used (on salty beaches).

It's deja vu all over again...didn't we have this conversation
once before (see post from 21 March below).  More refined modeling
shows the small 3-stack has peak gain around 21.7 dBi, not 19.6 dBi
mentioned below.

http://users.vnet.net/btippett/terrain_&_toa's.htm

                                                73,  Bill  W4ZV

K3BU:
>Using "crummy" 2 el. parasitic verticals and dysfunctional 3 el. triangular
>array sitting on the beach I came very close to W4ZV 10m score who was using
>optimized 3 stack KLM of 6 el. (Both in NC) (yea, yea, I am 5x times better
>operator, etc. :-)

Hi Yuri!

        Nice job from the beach!  Just for the record, here are the actual
numbers for the CQ WW CW on 10:

W4ZV            2009   37  138      31   1,021,825 PVRC
N2EE/4          1675   36  128             792,284

        I modeled a 4-square vertical system over salt water just for my
own curiosity.  If memory serves me correctly, it showed about 10 dBi gain
from about 1-14 degrees.  A 3-stack of 6 el monobanders has just under
20 dBi gain at a peak take-off angle of 6 degrees with a vertical beamwidth
of 6 degrees.  For higher angles, the lower two Yagis have <1 dBi less gain
at at take-off of 8 degrees and a 7 degree vertical beamwidth.  At this point
in the solar cycle, the vast majority of propagation to Europe is 3-10 degrees,
so the <3 degree angles where a saltwater 4-square would beat a Yagi stack are
not very predominant.  Salt water verticals for a temporary expedition work
very well but you need 4 each 4-squares to close the gap with a 3-Yagi stack...
and even that would still be >3 dBi below a 3-Yagi stack at peak angles.
(10 dBi/system + 6 dBi [for 4 each] = 16 dBi versus 19.6 dBi for a 3-stack.)

        Good luck this weekend and I hope you aren't trying to put up those
verticals in the 40 MPH wind-driven rain we're having here in NC today!

                                     73,  Bill  W4ZV (aka NY4A in CQ WPX)

http://lists.contesting.com/archives/html/Towertalk/2001-03/msg00427.html

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