On Fri, 12 Sep 2008 11:15:22 -0700, Dave G. wrote: >Can nyone provide me with the permeability number for the T37-2 and the >FT37-43 cores???
I also suggest that you study the material on ferrites in http://audiosystemsgroup.com/RFI-Ham.pdf The discussion of ferrites in this tutorial is considerably more advanced than what's on the Amidon site or in ARRL publications, and should give you a much better understanding of ferrites, how they work, and how to use them. Tne most important thing to understand is that permeability of ferrites is not a single number -- it varies (a LOT) with frequency. The commonly published number is the LOW FREQUENCY permeability. The second most important thing to realize is that ferrites are pure inductors ONLY at low frequencies. As frequency increases, resistance and capacitance become increasingly important, and at high frequencies R and C dominate (to the extent that there's no L!). When we use ferrites to wind coils for transceivers, we mostly care about L. When we use ferrites to suppress RFI, we only want R. Most (all?) ferrite cores sold to hams by Amidon and others are actually made by Fair-Rite, a very good US company based in NY State. They publish an excellent catalog that includes extensive data on all of their products. http://www.fair-rite.com/newfair/index.htm 73, Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
