Topband: Laird ferrites

[Tom W8JI]

> A different company, Laird, sells three main mixes of ferrite 
> toroids/beads/snap-ons: "LF", "28" and "HF". Graphs in 
> http://www.lairdtech.com/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=3363

> Laird mix 28 might be comparable to Fair-Rite 43, and Laird mix LF might 
> be good for 160M balun chokes. But maybe I'm comparing apples and oranges.

Unless I missed it somewhere, there isn't enough data in that link to judge 
how useful the cores are, or even what they are. Z by itself is not very 
meaningful.

For example, 500 ohms of reactance or 500 ohms of pure resistance both are 
Z=500. 500 ohms of pure reactance could make for very poor suppression for 
common mode, and could actually even hurt common mode suppression, but would 
always stay cold in high power applications. A pure resistance would make 
reliable common mode suppression, but could get hot in some high power 
applications.

To know the usefulness in various applications we have to know the real and 
imaginary parts or something that lets us know the real and imaginary parts 
of impedance.

73 Tom