[Amps] Queation on toroid core materials

Will Matney craxd1 at verizon.net
Wed Feb 1 15:24:54 EST 2006


All,

What has been your experience in the wide-band transformer core material types available for use on 160-10 meters in both Ferrite, and Iron Powder, or the types recommended to use? Available materials that have been used in Ferrite is 43 and 61 material with 43 material having the highest permeability of about 850u. 43 was recommended by Motorola in their HF amp designs for wide band transformers. However, 61 was recommended to me once because of the 43 material heating quicker, or saturating, and the heat ruining the core. 61 was supposed to cure this but with a loss of permability. Also, in wide band transformers, the upper frequency limit is said to be 10X higher, is this the same for iron powder the same as ferrite? In iron powder, the recommended types in color are Red (mix 2), White (mix 7), and Yellow (mix 6). Mix 2 is .25 to 10 MHz, Mix 7 is 1 to 20 MHz, and Mix 6 is 2 to 30 MHz. The permeability between the three is not much different so I would think using mix 6 (Yellow) would be the way to go but loose a small amount of permeability. If the X10 freq rule holds true for iron powder, then one could use Mix 2 (red) easily enough and gain it back. Generally, in any transformer, the upper freq. is not the problem, it's trying to use a core below its maximum lower frequency. That would hold true for either iron powder or ferrite I would think. What would any here recommend? This is for the RF transformer part of the software I'm writing.

Best,

Will



More information about the Amps mailing list