Are you certain the simulation program wasn't given, and doesn't take into account, the number of radials and the cumulative current gain?
It appears to show two of the four radials, one on each side, left & right, and being that it is designed to show a flat slice from one side for a visual representation of the actual radiation currents, it sounds like you're presuming that the program is making the same mistake you think I am, and not taking into account the parameters you mentioned.
- I have a hard time accepting that idea.
I believe we are seeing exactly what a field strength meter would show regarding the radiated field strength in each area of the antenna's vertical plane.
I just can't accept that the designer of that program would leave a large hole requiring mental gymnastics in order to correct it's 'flaws'.
It's common knowledge that the pattern of any balanced antenna will be distorted by the introduction of near field articles, especially when those articles are of a nature to resonate or reflect RF.
Even Sirio recommends keeping it ~6m above the roof.
When I first installed my SGM I was immediately disappointed.
I was an S-7 to Phil where the Imax had been showing an S-8.5 and the Penetrator ½λ away showed an S-9, all with his attenuator on.
After simply removing the Penetrator from the near field, the SGM came alive and was an S-9+2 on Phil's Pro3, and his signal increased ~3dB on my 751A.
(A line drawn from mine to Phil's QTH is almost directly perpendicular to a line running between the two antenna masts, which are ½λ apart.
With both antennas up there were up to 3 S-units difference off to the sides favoring either antenna depending on which side, so I discount those directions when testing and remain with signals only perpendicular to both.)
No doubt the SGM will function reasonably well when installed too close to another article or the ground, but I wouldn't expect the nice flat TOA or gain pattern to remain intact.
