Re: NEC-LIST: Helix antenna on ground plane

There are two problems that I think might be causing the bad readings.

First of all, you simply could not be using an accurate enough model.
Not likely, though, because a hexagon is a pretty good approximation
of a circle.

A more likely cause would be that the helix is attached to the ground
plane. Don't forget, MiniNEC assumes that two touching surfaces are
connected. If you had the height above ground equal to zero, then
MiniNEC would have had your antenna connected to the ground.
Solution: Make your antenna a very small distance above-ground.

Finally, your approximation may have changed the resonant frequency of
the helix.

I hope these few suggestions have helped.

<<Lawrence Weinstein>>
Received on Mon Jun 29 1998 - 09:14:08 EDT