More 4-square notes

[Bill Fisher, KM9P & K4AAA]

Just a follow up on previous messages regarding the 4-square I built...

1.  When I cut my RG11 coax, I cut to length using an SWR anaylyzer for the
proper length.  It was several feed different from the suggested length in
the manual that came with the 4-square box.  I would suggest not just
cutting it to a calculated length.

2.  It is suggested that you tune the verticals for 10% below the desired
frequency of operation due to mutual coupling.  In my case it didn't seem to
be anywhere near 10%.  More like 50KC on 80M.  So I tuned mine for 3475Khz
and 3775Khz.  The low dump power point in both cases is 50KC higher.

3.  I originally tuned mine for 3650Khz with the idea that I would live with
whatever dumped power there was on each mode.  After the first weekends
evaluation I felt like I was loud on CW but not so loud on SSB.  I also
didn't see as much F/B on SSB.  The next weekend I tuned the array for SSB
and the only test was the contest.  It worked FB.  

This weekend I decided rather than simply adding length to each vertical to
move it to cw, that I would add a coil on the bottom of each vertical and
short across it when operating SSB.  I wound the coil on a piece of plastic
pipe (about 5" in diameter).  It only took a 5 or 6 turns to bring it from
3800Khz to 3525Khz.  It also means that my verticals are truely vertical.
If I added length to each vertical wire, my supports were not tall enough to
keep the verticals vertical.  They would slope in slightly.  I figured
keeping the system vertical was more important than a whatever small loss
that would be seen in the coil.  I hope I'm right.  (any comments?)  

4.  K8CC told me that K3LR had problems with his 160m array detuning his 80M
4-square.  I have a 160M sloping vertical about 30' away from one of the
legs of the 4-square.  I have not seen any difference in dumped power
between any of the positions and the F/B seems to be consistant in all
directions.  I'm assuming it's not screwing the 4-square.  At any rate, it's
the only 160M antenna I have and it's staying up.  

Hope this helps someone.

73

Bill

Bill Fisher, KM9P & K4AAA
http://www.contesting.com 






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