A short while ago, I posted about an idea of a sort of homebrew
"steppIR" variable Moxon. Responses indicated that the Moxon design
required critical lengths and distances for the folded arms in the
design. I.e., this design was not feasible.

In the newest QST there is an ad for SteppIR's 30-40 M add-on element
that appears to be similar to what I was talking about.

How would this "folding" dipole behave and what is the difference
between what SteppIR has done and a theoretically variable Moxon?

Thanks

John
AB8O

John,

The Moxon is a beam that relies on the element end gap to set up the
feed impedance and directional properties. You basically need to
mechanically scale the whole array, width, depth, and gap in order to
keep it working like a Moxon.

The SteppIR curved dipole thing that goes down to 40m is just an end
loaded dipole that uses a transmission line stub as the loading.

It's just a regular dipole until the element goes around the curve,
then the doubling back adds a transmission line stub to the ends of the
dipole, bringing it to resonance at a lower frequency. I tried it in
EZNEC.

This would be a fairly buildable antenna except for the sliding
contacts at the feedpoint.

Dan

The Steppir looks more like linear loading of a dipole. Each side of the
dipole bent back on itself to give the effect of the full length without the
sides having to be 33 feet long.

The Moxon uses a driven element and a reflector - a 2 element system. The
ends are not folded back but go at a 90 degree angle. A Moxon looks like a
loop but the ends at the sides are separated by a calcuated distance.

We ran a 40 meter Moxon at Field Day and it was a very fine antenna.
--
K4ia
"Buck"
Fredericksburg, VA