Topband: FERRITE BEADS

[K9AY]

> If you use type 77 material (u=2000), use enough beads to cover 1 foot of
> the coax,.  The Amidon part # for type 77 beads is FB-77-1024, which has
> an I.D. of 0.5" and a length of 0.825", so it would take about 15 of
> these beads.

I concur that 77 material is a good choice.  It is designed for RF
applications and has lower loss than 43 or 73 materials, which -- by
design -- have higher resistive loss to absorb energy in EMI/RFI reduction
applications.  You'll get the required reactance with less heating of the
beads using 77 material.

> If you buy your beads directly from Amidon (the manufacturer of the
> beads), you'll get them for considerably less than from Palomar.  The
> last time I ordered from Amidon, their phone number was (800) 898-1883.

For the record, Amidon is not the manufacturer, just a distributor.
Fair-Rite Products is the manufacturer -- There is full product data and
list of authorized distributors at www.fair-rite.com

73 and Happy Holidays,

Gary, K9AY