Ferrite Bead Baluns

Nick,

Here is an excerpt from Chapter 21 of Reflections writtern by W2DU Walter Maxwell. "For practical baluns to be used from 1.8 to 30 MHz (less than 12 inches long, including connector), use a quantity of 50 number 73 beads (Amidon # FB-73-2401, or Certified Communications # 73-W2DU), The coaxial cable need be only long enough to hold the beads and to access the end connectors. At full legal input levels, no powerhandling problems will arise using these baluns, because the CW power-handling capability of the cable is 3.5 kW at 50 MHz, and 9 kW at 10 MHz. Any suitable connector that will mate with the load end of your feed line can be used at the input of the balun coax, and the balanced-output terminals may simply be pigtails formed by the inner and outer conductors of the balun coax. Methods for connecting the output terminals of the balun to the antenna are left to your ingenuity."

Ferrite bead material may be obtained from “The Wire Man”, Press Jones, N8UG, Certified Communications, 261 Pittman Road,Landrum, SC 29356, 800-433-9473 and 800-727-9473, e-mail n8ug@juno.com, and n8ug@thewireman.com, www.thewireman.com.

The Wire Man also has W2DU baluns available both in kit form and fully fabricated, ready for installation. (NOTE: W2AU baluns made by Unadilla are trifilar 1:1, and bifilar 4:1, ferrite-core, transformer-type voltage baluns.)

Ferrite bead material is also available from Palomar Engineering, Box 462222, Escondido, CA, 92046, www.Palomar-Engineers.com, e-mail palomar@compuserve.com.

Fully fabricated W2DU baluns are also manufactured by the Unadilla Antenna Manufacturing Company, PO Box 4215 BV, Andover, MA 01810 (508-475-7831), and are available at all Amateur Electronic Supply (AES) outlets."

I personally have bought both the W2DU pre-assembled and the W2DU kit and assembled it myself and they work!

Larry

Hi Nick,

While I don't have experience in building ferrite bead baluns, I looked around for some resources. Here are a few links for you to explore. This first one describes several types and sizes of ferrite beads, indicating how they are best used.

Amidon Ferrite Core Materials

This link contains numerous other links, including instructions for building ferrite baluns.

DX Zone

Finally, here is a list of manufacturers of ferrite beads throughout the world. There are lots of links to other resources, that may be useful to you.

World Wide Ferrite Manufacturers

Good luck!

---Michael

Thanks for all of your responses.

Much appreciated,

Nick