Re: NEC-LIST: Why coil-load?

I'd be surprised to see any significant difference between NEC-2 and
NEC-4 for an above-ground model like this.

I concur wholeheartedly with the approach. For reasons that are
mysterious to me, the vehicle is generally overlooked in the discussion
of mobile antennas. The vehicle is the other half of the asymmetrical
dipole being fed, and its radiation is at least as significant as that
of the "antenna".

Roy Lewallen

drcuthbert_at_micron.com wrote:
> Doug,
>
> A good question on the current distribution in the ground. I don't have
> a definitive answer- perhaps someone else does.
>
> I would approach the problem of the ground loss like this: Build a wire
> grid model of the vehicle and place it over Sommerfield-Norton ground.
> Then experiment with the loading coil Q and placement. I only have NEC-2
> and that will give optimistic results and will not have absolute
> accuracy. But it might be good enough for relative comparisons. If you
> have NEC-4 then you are all set. The vehicle model will be good for
> exploring the effect of nearby structures. For example, the center
> loaded whip mounted on the fender will have a higher E-field than the
> base loaded whip and will couple more current into the roof. This then
> travels down the roof pillars thereby lowering the radiation resistance.
>
>
> Dave Cuthbert

-- 
The NEC-List mailing list
NEC-List_at_robomod.net
http://www.robomod.net/mailman/listinfo/nec-list