Topband: Antenna Modeling

[GEORGE WALLNER]

>> Why is there apparently always such "black magic" 
>>surounding this sorta stuff...? No wonder there seem to >>be two camps anymore...

Eddie,

Fundamentally, it is simple. Think of antenna modelling as 
a "calculator". It allows you to save time. It allows you 
to test ideas. You could build everything you ever think 
of and test it, but it would be a time consuming and a 
money-wasting exercise. Antenna modelling allows you to 
test ideas without having to build them! Antenna modelling 
does not replace antenna building: a model does not work 
as an antenna; you can not connect a transmitter to 
it...but it allows to you check ideas out without having 
to build them.

Use EZNEC and start simple. Model a dipole. It is not too 
difficult to define a model in the spreadsheet: it is just 
coordinates (x,y,z)that describe the ends of the wires. A 
dipole is modelled by defining the end-points of its two 
wires. A few more other, more or less self-evident details 
(like segmentation = use 20) and next you are looking at 
the performance curves. Soon you'll see how it may work in 
theory. Is that an antenna; of course not, it is just a 
model. But it tells you a lot. Most importantly, it tells 
you what not to build!

Modelling  will let your creative mind run wild. Most of 
what you model will not work. But when something you have 
modelled does look good, and you have verified your data 
and the model, it is time to build it! It is time to test 
the idea!

Good Luck,

George, AA7JV