On Wed, 2 Jun 2004 18:44:28 +0100, "Richard"
wrote:

|IOW:
yes

|I'll see how I get along with the 4Nec2 program.
|
|What is the DE,just a regular hertz dipole? Is DE specified as to what it is
|(hertz, folded) somewhere in 4nec2?

No, it's not specified as such. Modeling programs assume straight
"wires" so to model a FD you have to "construct" one from straight
wires. This is not trivial however, so don't try it until you
understand the pitfalls of "closely-spaced wires."

I strongly recommend that you download Roy's EZNEC demo, if for no
other reason than to get the excellent "Help" section.


|In the Geometry Edit I see "Radius" for wire diameter I suppose. Do I
|calculate the radius from the dia given in the table above? TIA.

Yes.


Also, when you get to building the real antenna, you have the problem
of how to feed the DE. The design in question offers a nice 50 ohm
impedance, but just opening the center and feeding directly with coax
is going to be problematic. In the Arizona desert where I live I've
gotten away with pigtailing the coax and using ferrite sleeve baluns.
Since this is a marine band antenna, I assume there's water around
someplace and that may be unsatisfactory for you.

What did you have planned?