[RFI] Material 75 vs Material 31 Ferrites for EMI

[EZ Rhino]

Uh, I think you mean clamp-on's are a waste of money if configured in a single pass on a cable....if you can do multiple turns, you're good.  

Chris
KF7P



On Feb 10, 2017, at 15:42 , Jim Brown wrote:

Chuck,

I looked into this half a year ago when someone asked the same question. The answer was no. I don't remember why.

Study my material on this topic. Below 5 MHz, we need multiple turns through a #31 core. Between 5 MHz and 6M, we need multiple turns through #31 or #43.

Clamp-ons of either are a waste of money and do nothing at HF.

73, Jim K9YC

On Fri,2/10/2017 12:10 PM, Chuck Gooden wrote:
> 
> Fair-Rite has introduced a new low frequency material (#75), I was wondering if someone could comment if this new material would be better that #31 for EMI suppression.
> According to the Fair-rite web site, #75 shows a higher impedance at lower frequencies than #31 but above ~2 Mhz the impedance drops off.  While the impedance of #31 seems to continue to increase and the frequency goes up.
> 
> I am planning on ordering some snap-it cores  to reduce the noise from switch mode power supplies, and other sources, I am experiencing on HF bands.  I have already read the documents on the K9YC web site but there was no info on the new material.  I am tempted to stay with #31 due to it's long time use.
> 
> Thanks,
> 
> Chuck K9LC
> 
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