On Tue, 11 Oct 2005 02:57:44 GMT, "Frank"
wrote:

----------o---------- ----------
dipole extension

Do you think it makes sense? It is the only way I could think of modeling
it with NEC.

Hi Frank,

No. The extension lies in the null of the dipole. As such, it would
be no mystery that it has so little influence.

To model it correctly requires some form of cage or skirt of wires as
Wes has provided in this thread.

73's
Richard Clark, KB7QHC

I did not notice that somebody had attempted what you suggest. I translated
the coordinates into regular NEC2, and it does run. It appears to violate
some NEC2 criteria, but not sure how critical the model is.

Which criteria?

Obviously I
cannot use the "Minninec" ground, so have substituted an average S/M ground
with the coax end about an inch above the ground. I had assumed the antenna
was for HF, so it is probably impractically high, causing multiple lobing.

The multiple lobes are what you should see and are exactly my point.

A free space model might provide more meaningful results.

If you can operate your antennas in free space then they would be
meaningful.

If you can't/won't buy Roy's fine EZNEC program, then may I suggest
4nec2 at zero cost or MultiNEC at nominal cost as alternatives to bare
NEC.