Re: NEC-LIST: Efficiency of Short Dipoles

From: Hal Smith <halsmith_at_email.domain.hidden>
Date: Fri, 19 Dec 1997 08:44:46 -0600

Peter Excell wrote:
> >
> > My information indicates that mu(r)= 1 at HF frequencies for most
> > steels, irons and other non-laminated metals.(gyromagnetic limiting
> > frequency approx 20 kHz).
>
> I looked into this some years ago and the magnetics textbooks (I recall
> Bozorth in particular) seemed to me to be saying that ferromagnetic
> behaviour endured up to a few hundred MHz at least.
 
Peter
 
Obviously there has to be ferromagnetic behaviour at VHF and above given
the ferrite materials used in inductor cores, hybrids, etc. That may not
be totally relevant since the thread is about solid stainless
structures, etc. but at least in the case of a ceramic/fine magnetic
powder construction there are ferromagnetic effects at high RF.

Do any of the NECs model ferrites?
 
Sincerely
Hal Smith
AM/FM Services Company
Edmond, OK
Received on Wed Dec 24 1997 - 12:02:28 EST

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