[TowerTalk] 80 M 4 SQUARE MODELING

Jim Thomson jim.thom at telus.net
Sat Jul 22 11:55:32 EDT 2017

Date: Fri, 21 Jul 2017 19:08:17 -0400
From: "StellarCAT" <rxdesign at ssvecnet.com>
To: <towertalk at contesting.com>
Subject: Re: [TowerTalk] 80 M 4 SQUARE MODELING

<That stated the results were disconcerting enough for me to decide not to do 
<it. Besides in my case if the published data re ground characteristics is 
<correct, poor in this area, then my rotary dipole at just over 1/2 wl on 80 
<equals or beats a 4 sq a good part of the time. So I just put it back up. If 
<one WERE going to just do it - I'd have a plan in place on how to mitigate 
<it, if indeed it is there .

<My guess, Bill, is that your tower w/ antennas will look like, easily, a 
<120'+ tower ...


##  The loaded 80m rotary dipole, may well be a lot simpler..and quieter. 
With a tornado drive on it, it will tune the entire band.   Feedpoint is right at 
the mast, so any CM choke, helical hairpin, coax is easy to get to. Mounted
inline with any  yagi booms above or below it, there is no interaction with other
yagis on the same mast.  Windload is a moot point, since with yagi eles  broadside
to the wind, the 80m dipole is pointed into the wind.  No snow or ice in KH6. 

##  The 80m 4 square, hanging from the tower, will have the obvious advantage of
instant direction switching.   I assume the tops of all the 80m verts  will converge a bit
towards the tower?   How much effect, if any, does that have ?       Do you have room 
for a dedicated 80m RX ant array ?  If any dedicated 80m RX array is used, then you 
also have to get the RX array a min distance away from the TX array.  

Jim  VE7RF

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