On Sun, 09 May 2010 12:50:37 -0700, Jeff Liebermann
wrote:

On Sun, 09 May 2010 14:26:24 -0400, John Ferrell
wrote:

I have been thinking about the SteppIR Antennas. There is no way I
will ever justify the money for one. Has anyone pondered the problems
from a HomeBrew stand point. It seems to me that the first challenge
is to couple the radiator to the feed line. The rest is simply (maybe
simply is not the right word...) mechanics.

Whatever form the radiator takes it needs to be wound on a spool like
mechanism.

Well, if you're going to clone it, these might offer some clues:
www.w4gkf.com/steppir/
Lots of photos. Perforated flat copper "tape" is used for the
elements. Sprokets inside the motor assembly unroll the tape from a
spool which is then fed into the fiberglass support tubes. The
electrical connections to the elements is with a simple wiper contact.
There's a view of the guts about 4 photos down from the top:
http://www.w4gkf.com/steppir/n4dk/

Some interesting stuff from the patent:
http://www.google.com/patents/about?id=CjKhAAAAEBAJ&dq=steppir

If you're planning on cloning the antenna, I suspect your biggest
challenge will be the wide variety of custom fabricated mechanical
parts required. Making adjustments and modifications on top of a
tower is also not my idea of fun. I could probably design one
suitable for home brew, using round wires on spools with pulleys at
the element ends, but the result will probably not survive the first
storm.
Thanks for the url's. I am not trying to clone it, just impliment the
concept. I do my antenna work on the ground with a minerature version
of the Tilt-Plate concept. I do my antenna work with both feet firmly
on the ground.

A Home Brew version of the variable geometry beam antenna seems to me
like a good place to learn a bit.
John Ferrell W8CCW