You are talking a little over this sailor's head but I think I got the jist
of it.

The antennas are basically Bill Sykes and Bob Cobey's design.
http://www.askrlc.co.uk/. I did change the ratio of height to width a
little but verified the dimensions with John Copens' calculator.

The loops are different lengths so I would say it is self phasing. Both
antennas are 3/8" tube but the copper is .065" wall and the stainless is
..028" wall. Also at corners I used long Ell sweat fittings on the copper
tube and bent the stainless on a 3/4" radius but the total centerline
lengths are within half a mm on both antennas.

I have tried two different balun designs. One is Paul Hayes design
http://web.ukonline.co.uk/phqfh/phbalun1.pdf built inside a film can and
the other just 4 turns of RG58U around the 1 1/2" support column. The RG58U
balun worked better than the film can (probably due to my poor workmanship)
but the relative performance between the two antennas was the same.

I did read your QFH article in Reflections 2. Even understood about half of
it. :-)

I have plenty of stainless tube and building these things and seeing how
they work is fun so starting over from scratch would not be a problem.
Would 3/16 solid rod work better?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Walter Maxwell" wrote in message
...
On Tue, 11 Jan 2005 07:55:19 -0500, "Glenn Ashmore"
wrote:

I understand that you are the resident authority on QFH antennas. Can
you
help with this problem?

Hello Glenn,

I've had some experience with the QFH, Glenn, but I don't consider
myself an authority. However, I'll try to help you with the problem,
but first I'll need to know the form you used in your model. Is it
the self phasing type, with the inductive bifilar longer than the
capacitive one? Or are both bifilars of the same length and fed with a
power splitter and a 90° hybrid? If it is the self phasing type what
diameter is the tubing? And have you reviewed my data on the subject
that appears in Reflections?

If both the copper and stainless steel models are fabricated in
exactly the same form there shouldn't be much difference in
performance due the different materials. I don't believe the
difference in resistivities of the two materials should have a
significant effect on their performances, unless your bifilars are
made with very small diameter wire. If you used the self phasing type
the tubing diameter should be approximately 3/4", in which the
difference in resitivities would be absolutely insignificant.

So Glenn, give me the details of your QFH so that I can be of more
help.

Walt, W2DU