[TowerTalk] Ferrite Cores in Trapped Dipoles

Dan Zimmerman N3OX n3ox at n3ox.net
Tue Feb 6 19:10:58 EST 2007

> A trap, especially at high power, is not a good place to use any kind
> of ferrite or powdered iron core. Ferrite is notorious for saturating
> on current peaks and thereby causing distortion and harmonics.

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

There *is* a QRP-level trapped dipole (don't remember the callsign
associated with the design) out there that uses small iron-powder
cores for compactness.  For low power levels and portability, maybe
it's not such a bad idea.

So you should watch out for saturation if you're designing a trap this
way but it's not a deal-breaker.


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