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[TowerTalk] Receive 4-Square

To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: [TowerTalk] Receive 4-Square
From: Roger Parsons via TowerTalk <towertalk@contesting.com>
Reply-to: Roger Parsons <ve3zi@yahoo.com>
Date: Fri, 3 Oct 2014 06:28:16 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Many thanks to all who replied to me both directly and to this reflector.

Firstly, I have some egg on my face. One of the verticals had a corroded 
connection, and on fixing that the array seems to work significantly better. I 
am pretty confident that the system is now working as it should.


I have had the system for several years, but until this summer I did not use 
the 'crossfire phasing' technique so it was really quite narrowband. I very 
much take on board the need to evaluate it over a lengthy period - I find that 
even my long Beverages sometimes have zero directivity. Last evening it had an 
F/B ratio varying between 15dB+ and very little on W1BB.


The hybrid combiners used are not quadrature hybrids - they (ideally) have zero 
phase shift between input and output. The phase shift comes from the two 
lengths of URM70 (75 Ohm cable) shown on the schematic as 60 and 120 degrees, 
and the element phases should be 0/120/240 degrees. As the verticals are 
heavily resistively loaded there is very little mutual coupling which greatly 
simplifies design.

Thanks again to all

73 Roger
VE3ZI
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