Topband: EZNEC prediction help

[Tom Rauch]

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

3dB max gain is the maximum gain at any direction and angle
where it happens to occur.

Average gain is an expression of the efficiency of the
antenna. How much RF you lose as heat.

> 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.

The reason your shorter antennas are better is almost
certainly because the model is not giving accurate results
due to flaws in the model or modeling.

All NEC programs have the toughest time dealing with and
accurately calculating performance of radiators close to
real earth. You can't even input a close model of the soil,
so how can results be more than very rough results? I doubt
anyone has homogeneous soil with uniformly distributed loss.
Plus Eznec uses NEC2.

Another problem is when you make a lot of bends and connect
dissimilar sized conductors, it can totally hose up the
results.

Eznec is a very good modeling program as long as you don't
try to use it for answers it can't accurately do. You have
to read the manual to know the limits and it is a pretty
long manual.

73 Tom