[RFI] Snap on split beads; coax high-pass filter recommendati ons

Jon Ogden Jon Ogden <jono@enteract.com>
Wed, 01 Dec 1999 16:50:42 -0600

on 12/1/99 16:38, EDWARDS, EDDIE J at eedwards@oppd.com wrote:

>> At a hamfest a couple of months ago, a guy was selling some neat split
>> ferrite beads.  The idea is a little like the snap-on rectangular ferrites
>> that Radio Shack et al were selling, except that these involve a split
>> bead
>> 1/2-3/4" long enclosed in a plastic shell that can be snapped open and
>> closed.  He had 2 sizes, for different sized cable.  Does anyone know of
>> an
>> economical source for these?
> [Ed-K0iL]  Radio Shack does sell both types of ferrites: split bead
> snap-on in a white plastic case, and rectangular core wind-on type in black
> plastic that you mentioned.  Both are in the 273-series (-104 & 105 I think)
> and are probably 43-mix.

The stuff Radio Shack sells is Type 43.  That's not what you want to use for
HF attenuation.  I think this sort of thing is what give ferrites a bad
name.  Type 43 is better for probably 20 MHz up to a couple hundred or so.
Type 77 is good for the entire HF band.

> These can also be had at Surplus Sales of Nebraska, Palomar, Amidon,
> MFJ, Kilo-Tec, Ocean State Electronics, and direct from some of the
> manufacturers like Fair-Rite.

I believe Palomar sells split beads.  They advertise them, but I've not seen

Ed is correct though in that a split bead is not near as good as multiple
turns of cord through a big torroid.



The Second Amendment is NOT about duck hunting!

Jon Ogden


"A life lived in fear is a life half lived."

Submissions:              rfi@contesting.com
Administrative requests:  rfi-REQUEST@contesting.com
WWW:                      http://www.contesting.com/rfi-faq.html
Questions:                owner-rfi@contesting.com