Re: NEC-LIST: Extracting Q factor for an Antenna -- Postscript

> Help, Does anyone know of a way of extracting Q factor for an
> antenna from NEC 2?
>
> Alan Johnson

If one dashes off a reply too quickly, one forgets an important point.

I said in my earlier message that an antenna is an La-Ca-Ra circuit
(every one knows this). NEC computes the series impedance, which for
a dipole is capacitive below resonance, and inductive above resonance.
But this is not useful to draw an equivalent circuit.

For the case of resonant antennas there is an important reason to know
the Q-factor, because for a small range of frequencies about the
resonant frequency, we can calculate La and Ca, since

Q = (2 pi f La)/ Ra = 1/(2 pi f Ca Ra)

This simple equivalent circuit is often useful.

Jack

_____________________________________________
John S. (Jack) Belrose, PhD Cantab, VE2CV
Senior Radioscientist
Radio Sciences Branch
Communications Research Centre
PO Box 11490 Stn. H
OTTAWA ON K2H 8S2
CANADA
TEL 613-998-2779
FAX 613-998-4077
e-mail <john.belrose_at_crc.ca>
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Received on Fri Mar 05 1999 - 17:27:13 EST