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[TowerTalk] 40m 4 Square

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Subject: [TowerTalk] 40m 4 Square
From: (Tom Rauch)
Date: Tue, 3 Jul 2001 23:26:59 -0400
> This is an interesting question.  
> What is the advantage of a 4 square over a 3 vertical array.  I
> have a 3 vertical array on 40 and it is switchable in 6 different
> directions.  Directivity seems to be very good.  What would be
> the advantage of going to a 4 square over a 3 antenna array?

Probably not much, if the three vertical array is done correctly.

Traditional 4 squares with 90/180 degree phasing are off a tiny bit 
in phase delay from optimum, so they don't work quite as well as 
they actually could. 

That hurts gain about a dB, and F/B several dB.

If you compare a traditional 40-square (90/180 delay) to a three 
element array with 1/8 wl spacing (two elements active) using 
proper phasing ~135 or 140 degree phasing), the four-square has 
less F/B ratio and about 1.2 dB more gain.

Eznec shows 5.33dBi gain for the four-square and 25dB F/B, and 
4.01 dB with 30 dB F/B on a two active element antenna with 1/8th 
wave spacing.

There obviously isn't a large difference.

I use 120/240 shift in my four square, which makes it about the 
same F/B as the two element (~30 dB) but also gives about one 
more dB gain over a regular phase-shift four-square (6.5dBi gain 
using the same ground loss and frequency band as the other two 

Still a small difference, unless you are fighting for every last dB.
73, Tom W8JI 

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