haha - That is funny, and this thread is too. Check this out from:
End-fed Vertical and J-pole
You need to go there to see the pics. Seems the modeling software no likey the Imax.
I-Max 2000 Solarcon A-99 Antenna
The following model is an I-Max 2000 5/8th wave vertical with a vertical feedline or mast connected to the antenna base, and no radials. In this case I picked the worse case multiple of feedline or mast length:
Feedline current is 100% of antenna current. This illustrates why so many people complain about SWR problems and RF in the shack with end-fed verticals like the I-MAX 2000! Other people do not complain and seem to love the antenna. This is because some people pick a lucky mast height or feedline length, while others are not so lucky. They chose a mast height, feedline length, or grounding system length that enhances common mode.
Here is the pattern of an antenna that copies the I-MAX dimensions and feed system:
This is a NEGATIVE gain antenna at low angles. A 1/4wl groundplane would seriously out-talk the I-MAX 2000 or any other 1/2 or 5/8th wl antenna that does not have a large groundplane.
Even if we use the optimum feedline and mast length, here is the very best the end-fed antenna will do:
In this case we now have 2.67 dBi, which is actually a little less than a 1/4wl groundplane will do! The severe common-mode mast and feedline currents make "no-radial" verticals extremely sensitive to mounting height, mounting structure, feedline length, and grounding. This is NOT normal for antennas, it is a sign of a design problem.
Lazybones, this article claims a worse case use for the Imax noted in the image shown. The author does not tell us what that height is, but can we tell anything from that picture that suggest approximately what the height might be?