"Walter Maxwell" wrote in message
...
On Fri, 09 Mar 2007 12:56:12 -0800, Roy Lewallen wrote:

Ralph Mowery wrote:
Has anyone thought of trying to use some of the ferrite beads to isolate
the
guy wires of a tower for RF so the tower could be shunt fed ? Along the
same
lines could the beads be used to electrically brake up the wires into
non
resonate lengths ?

It would require multiple beads at each point, and at multiple points.
While it could be made to work, it would be heavy and expensive. That's
why egg insulators or non-conductive guys are used instead.

Roy Lewallen, W7EL

Yes Ralph, beads could be used to achieve what you want. I refer you to a
paper
that will appear in Reflections 3 as Chapter 21A, which is a continuation
of
Chapter 21 in Reflections 1 and 2. Chapter 21 tells of the need for a
balun, and
how the beads perform as a balun.

However, Chapter 21A describes how I developed the idea for using beads
for the
W2DU balun. The idea came as a spin-off from a method I used during
radiation-pattern measurements for the antennas that flew on TIROS weather
satellites. The downlead for the signal received from the antennas on the
satellite was reradiating EM energy, and distorting the radiation
patterns. I
reasoned that placing a bead every quarterwavelength along the downlead
would
breakup the current on the lead, which it did. I then transformed the idea
into
the W2DU balun, which is described in all editions of the ARRL Handbook
since
around 1985. Chapter 21 is a repeat of my article in QST for March 1983.

Chapters 21 and 21A can be found for downloading on my web page at
www.w2du.com.
Click separately on 'View Chapters from Reflections 2' for Chapter 21, and
click
on 'Preview Chapters from Reflections 3' for Chapter 21A.

Hope this helps.

Walt, W2DU

Walt I have seen some of your work in the handbooks and it makes for good
reading. I do use a current balun on a triband beam I have up.

I just have not seen any beads used on guy wires and did not know if it had
been tried. I agree it probably would be beter to just use the insulators
on the guy wires, but not sure how the price of them and the clamps would
compair to the beads. With the guy wires already in place it may just be
easier to place some clamp on beads on the guy wires if it would work.

73 de KU4PT