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

EDWARDS, EDDIE J EDWARDS, EDDIE J" <eedwards@oppd.com
Thu, 2 Dec 1999 09:18:47 -0600

> -----Original Message-----
> From:	Jon Ogden [SMTP:jono@enteract.com]
> on 12/1/99 16:38, EDWARDS, EDDIE J at eedwards@oppd.com wrote:
> > [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.
	[Ed-K0iL]  I disagree Jon.  I have not found 77 mix to work very
good at all across the HF bands where 43 mix almost always has worked for
me.  This is all very anecdotal, but the numbers that the Palomar guy quoted
seem to match my experience with them.  

	I have tried 77 mix on audio rectification problems from 14 MHz
signals and it had absolutely no effect.  (I actually thought it might've
been a little worse!)  Whereas the 43 completely eliminated it using same
size toroid.  

	Have you really had good results using 77?

	de ed -K0iL

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