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Re: Wire length,resonance, and Q (fwd)



---------- Forwarded message ----------
Date: Tue, 12 May 1998 09:04:05 -0500
From: David Huffman <huffman-at-fnal.gov>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Wire length,resonance, and Q

I didn't think this is true. The max frequency. occurs when the wire is
straight and in a vacuum with nothing else around it. As soon as you begin
to coil the wire the resonance goes down.
Dave Huffman

-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: 'Tesla List' <tesla-at-pupman-dot-com>
Date: Tuesday, May 12, 1998 2:59 AM
Subject: Wire length,resonance, and Q


>
>----------
>From:  bmack [SMTP:bmack-at-frontiernet-dot-net]
>Sent:  Monday, May 11, 1998 9:43 PM
>To:  tesla list
>Subject:  Wire length,resonance, and Q
>
>To all,
>
>When Dr. Tesla made initial coil designs, he often resorted to quarter
>wave length calculations as a guide.  My early impressons of this was
>that it was the upper boundry for the physical length of wire that could
>be used.  Since, however I found that this is not neccessarily the case.
>
>The most intriguing thing is the cases where the coil resonates at
>frequency HIGHER than the wire length alone indicates!  Malcolm made
>a passing refence to this in one of his recent posts as well.  Preliminary
>quick experiments indicate that the coil geometry has alot to do with it's
>ultimate resonant frequency apart from the length of the wire.  Really
>bizzare things happen when the aspect ratio is below 0.1.
>
>According to conventional physics, (let me know if I missed something)
>a charge and it's attendant feilds will propagate faster  in a straight
>wire
>than in a coil. It follows that the coil should always resonate lower than
>the wire since the velocity is less than the speed of light.
>
>Why then, do long space wound coils resonate at a frequency higher
>than expected? This has nothing to do with the LC ratio either. I would
>expect that no matter what gain or reduction of L vs C for a given
>geometry, they should always result in a frequecy lower than that of
>a straight wire.  Whats going on here???
>
>Before I go and re-invent the wheel, does anyone have an explaination
>and/or experimental data on this?
>
>Curious in NY
>Jim McVey
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