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