NEC modeling approach

[donuted967]

Dear all,

I am trying to create NEC-4 models of various existing dipole antennas. My approach has been to rely heavily on manufacturer provided free space gain patterns and consider myself successful if I can match them. I intend to measure the effect of structure on these free space patterns using UTD software. I figure that if I can match the radiation properties (power and gain), I may not have to concern myself with the circuitry leading up to radiation. Is this and acceptable practice? Any thoughts?

Thanks a lot,

Ed

 

[VEBill]

The relative accuracy of measurement versus prediction can be debated. Often, the two can be brought into better alignment by adding sources of measurement error, for example reflections. It is not necessarily a safe assumption that the measurements represent reality any better than a prediction. This point relates to the 'manufacturer provided' data; don't assume that it is perfectly accurate.

A good sanity check is to integrate the measured or predicted gain over the entire sphere. Don't forget to properly weight the poles (nadir and zenith) for a Mercator data set. The integral should obviously be 0.0 dBi (possibly with some loss for measured data).

Here are some links:

http://www.maasdesign.co.uk/aldas.html#linkName7

http://www.maasdesign.co.uk/maas/installed.html

ALDAS is a GTD/UTD package.