Topband: Laird ferrites

[Jim Brown]

On 7/2/2012 9:46 PM, Lee K7TJR wrote:
> It's been there all along guys.

Not ALL of it, Lee. I've searched for 20 minutes and still haven't found 
any specs for the materials.  They're simply called Broadband, High, and 
Low, but no data for u' or u'', nothing about the material properties. 
There's only one toroid that is physically large enough for our uses, 
it's the so-called Broadband material, and the resonance is above 500 
MHz (where the impedance curve stops), which suggests that it may be 
even higher Q than Fair-Rite's #61 material. #61 is a good material for 
inductors and transformers to handle power on the HF bands, but it isn't 
useful for supporession (chokes) below at least 300 MHz. Beyond that, 
the data sheet is so slim that I'm making an educated guess. And that's 
the ONLY material used in a big core.

Data for transformer and inductor cores is better, and I could see many 
circuit designers having enough to go on.  But not for suppression 
(i.e., chokes) at HF.

Thanks for the link.

73, Jim K9YC