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 (Ye
llow) 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
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