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Old March 26th 04, 12:51 AM
Cecil Moore
 
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Dave wrote:

"Cecil Moore" wrote:
5000+j0 at 7.118 MHz - anti-resonance


making up terms again cecil?? I have never heard of 'anti-resonance' and
don't see it in my references here... i would say it is just resonant at the
second harmonic, just because the impedance is high doesn't mean it is
'anti' anything, or anything else special. it is just plain resonant at
7118.


There's lots of thing of which I am ignorant but I don't make postings
about those things. The first four books I picked up had information on
anti-resonance. Are you familiar with books? :-) A web search for
"anti-resonance" turned up 700 hits. Perhaps you don't need a book.

_Radio_Handbook_, 20th edition, by Bill Orr: "In radio circuits, parallel
resonance (MORE CORRECTLY TERMED ANTIRESONANCE) is more frequently
encountered than series resonance; ..." emphasis mine

_The_ARRL_Handbook_, 17th edition, page 14-5: "A capacitor connected across
a cavity provides an ANTI-RESONANT notch below the resonant frequency (f0),..."
emphasis mine

_Electronic_Fundamentals_and_Applications_, John D. Ryder, page 287 under
section 9-13. Parallel-Resonant Circuits: "The total admittance of the
parallel-resonant (SOMETIMES CALLED ANTIRESONANT) circuit is ..."
emphasis mine

_IEEE_Dictionary_: "antiresonant frequency - Usually in reference to a
crystal unit or the parallel combination of a capacitor and inductor."

Since the resonant feedpoint impedance of a 1/2WL dipole acts somewhat
like a series resonant circuit, at Texas A&M we called that the resonant
frequency. Since the resonant feedpoint impedance of a one-wavelength
dipole acts somewhat like a parallel resonant circuit, at Texas A&M we
called that the anti-resonant frequency. Differentiating between the resonant
frequency and anti-resonant frequency gives one additional information
about the impedance to be matched. "Resonant" = low, "Anti-resonant" = high.
It's a useful concept. You really should try it.
--
73, Cecil http://www.qsl.net/w5dxp



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