On 28 Jan 2004 03:39:57 -0800, (Maurizio) wrote:

Hi all,
Is there anybody with some experience in MF antenna modelling with
ground effect included (surface wave/space wave) etc. ?
I have the need to find out if the NEC4 is able to modellize this type
of antenna in a general environment and with which performance.
Otherwise, I will have to find out alternative ways (FEM/...).

Thanks in advance for any suggestion


Best regards


Hi Maurizio,

Antenna modelers (NEC engines) render far, far field results. The
effect of ground is considered only for
1. its impact on feedpoint Z;
2. equivalent launch angle (from the perspective of very far, or DX,
receivers).

What you describe as your need sounds more like the province of
propagation modelers. There are some add-on packages that incorporate
with antenna modelers to allow for a variety of terrains; but even
those, I think, still relate to the very far, DX, receivers.

Even the propagation modelers (like VOACAP and VOAAREA) are tailored
for HF and the far, far field. Our references from the FCC for MF
broadcast stations stands as a resource. Those references go back
many years and little has advanced the science as it has served the
industry very well.

73's
Richard Clark, KB7QHC