There are many parameters to chose in designing an antenna. Beyond the
antenna itself are the costs, tolerable size, available materials and
available tools.
I recently took the ARRL antenna course and purchased Roy's EZNEC+
program. I describe my current level as an "advanced beginner".

I once scaled a 4 (5?) element yagi for an antenna measuring event
from the Arrl Handbook to 1296mhz using a piece of plastic tube for a
boom and #12 wire for elements. The measured gain and the plot looked
pretty much like the book said it would. It fits in a "book-sized"
box.

My current project is "What can I do with a 20 foot radiator?" Working
out the details (the devil is indeed in the details!) sure is a lot
easier with EZNEC than it is with physical modeling.

There are not many antennas that cannot be evolved from a straight
piece of wire.


On Thu, 12 Jan 2006 00:39:01 GMT, David
wrote:

Can someone explain to me how a new antenna design is started. Do you
take an initial standard design and then enter it into a modeling
program and optimize it for the required parameters ?

Is there a suitable reference book that would explain this process. I am
thinking about the Cebik antenna modeling book but think this may only
cover how to model and change an existing design,would it cover how to
come up with the initial design in the first place ?

Example: Say I want to design a 4 Element Yagi at 921 MHz using 6mm
diameter elements.

Is there a standard formula that would be used to calculate initial
lengths and distances between elements. Then you enter this design into
say EZNEC and use the optimizer to tweak the design.

Thanks in advance

Regards

David

John Ferrell W8CCW