Topband: EZNEC prediction help

[Rick Darwicki]

Can anyone familiar with EZNEC please give me a hand? The program is very accurate, at least when I modeled my Create 40/80 vertical the predicted results were right on the money with actual readings.

The problem I'm having is understanding the various readings, mainly the 3d Max Gain and the average gain. 

A full size 1/4 wave 160 vertical shows a 1.41 db max 3D gain and an average gain of -3.63. Used Mininec/medium ground.

All of the bent, twisted and short stuff that will fit on my lot calcs at a higher 3D max gain and less negative Average gain.  Would the gain difference be due to the radiation pattern? IE might one of my bent bananas be 3 db better than a full size antenna in some direction?  I'd take the full size any day. 

One very interesting calc was adding a top wire to the 40/80 Create ground plane with radials on the roof and fence. Then rerunning with as much of the radials as possible laying on the ground (.1 ft). The Z shot way up.

Typically I used the same ground configuration for all runs and added some 50-200 XL to get as close to J = 0 as possible with the wires that fit on the lot.

Below are the various results........So, what do it all mean ???? Thanks in advance

Rick N6PE

      Antenna 3D Max Gain Average Gain Z ohms  Base coil 
          
      Full size 1/4 1.41 .433 = -3.64 36.65 + j2.973 0 
                
      Inverted L 33 up 85 out Elevated radials 6-14 ft hi 3.26 .583 = - 2.34 5.676 - j3.262 136 ohms 
         
      Inverted L 33 up 80 out Elevated radials 6-14 ft high with 50% of length on ground 4.4 0.588 = -2.31 20.58 =+j0.23 0 
         
      Inverted L 50 up 85 out, ground mounted 2.52 0.539 = -2.68 10.34 -j.02288 42 
         
      Inverted L 33 up 80 out, ground mounted 2.77 0.555 = -2.56 6.621 -j1.025 180