[TowerTalk] Ferrite Cores in Trapped Dipoles

Michael Tope W4EF at dellroy.com
Tue Feb 6 23:23:39 EST 2007

----- Original Message ----- 
From: "Dan Zimmerman N3OX" <n3ox at n3ox.net>

> Yet many of us are using autotuners (which all have powdered iron
> inductors) on pathological matching cases, probably with high
> circulating currents.

You can get reasonably good Q's with iron powder. They are often
used in linear amplifier tank circuits for instance (most of the Alpha 
amps use an iron powder core for the low frequency portion of the
tank circuit). This will give you a smaller inductor (what counts in a
desktop amp), but not necessarily a lighter inductor (what counts
in a trap). Also, I think iron powder is pretty hard to saturate 
compared to ferrites due to the distribute air gap effect (iron 
particles suspended in a low mu binder).  

It seems like an interesting trade space to explore.

73, Mike W4EF......................

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