[TowerTalk] modeling compare: 80M, 2EL vs 4SQ

[Pete Smith N4ZR]

I think both John's and Gary's commemnts square with the series on 
radials that was on NCJ a few years ago. The message I took away from 
those articles is that if your actual ground characteristics are good, 
the improvement with radials, no matter how many, will be quite limited, 
while if your ground isn't good to start with, radials can make a lot of 
difference in the pattern, especially at low angles.

73, Pete N4ZR
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On 3/14/2015 10:59 PM, john at kk9a.com wrote:
> I do not believe that the radials will have an effect on the radiation
> pattern.
>
> John KK9A - W4AAA
>
>
>
> To:	<towertalk at contesting.com>
> Subject:	[TowerTalk] modeling compare: 80M, 2EL vs 4SQ
> From:	"StellarCAT" <rxdesign at ssvecnet.com>
> Date:	Sat, 14 Mar 2015 19:47:59 -0500
>
> Hello all.... please forgive the rehash but I feel a bit excited, at least
> for
> me on finding out HOW IMPORTANT ground quality is in evaluating a 4sq.
>
> Brief history: I had a rotary dipole in Arizona on 80 at 131' and it
> performed
> very well equaling and often beating out 4 sq's in the 'area' (few hundred
> miles out) very often except on LP.
>
> So I'm moving to South Carolina and planning on a station there. I'm
> wondering
> about 80. Do I do the rotary again? Do I do a 4 sq? (dreaming: 2 el?)
>
> I've never seen a model of a 4 sq that included radials (EZNEC-5) ...note:
> I'm
> sure they're out there - just haven't seen one. So comparing to me was a bit
>
> meaningless using the
> provided 4square that comes with EZ (it has none). So I read the manual
> again
> and I believe figured out how to do the radials - or at least an
> approximation
> of them.
>
> If I put in 17 radials that are each 0.15 WL long at 0.3 ft above ground
> (the
> elements starting here as well)... this allows me to provide a
> non-overlapping
> radial field (so no worries
> about problems with EZNEC geometry check). I know, I know - short and few -
> but
> that is addressed later...
>
> Using 2mS and comparing its results to a 130' high dipole the dipole is
> equivalent at essentially all angles and exceeds the 4sq at 10 degrees with
> more than 2db more gain at its peak of 24 degrees.
>
> If I change to 8mS, about what I had in AZ, indeed the crossover point is
> now
> 19 degrees and the 4sq is 5db stronger at say 5 degrees showing what I often
>
> saw on LP and very long contacts again in AZ.
>
> If I change to 30mS ... what some people have - wow - big difference. The 4
> sq
> REALLY plays well.
>
> Going back to SC where the ground is 2mS: If I add in a 2el beam at this
> same
> height as the dipole and compare it to the 4sq ... well now the beam is
> better
> at all angles... 3db better at 5 degrees and 6db at 15 deg.
>
> Of course I know there will be a difference in the 4sq with longer and more
> radials. Where I'm stuck is how to add these with the geometry check of
> EZNEC.
> (Or even more complicated: how to do the '+' center connection rails often
> shown for a 4 sq radial system).
>
> If anyone can help please drop me an email at
> garymyers at powerc dot net. Thanks,  Gary, K9RX
>
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