Re: Wire length,resonance, and Q (fwd)
---------- Forwarded message ----------
Date: Tue, 12 May 1998 17:04:04 EDT
From: Mark S Graalman <wb8jkr-at-juno-dot-com>
Subject: Re: Wire length,resonance, and Q (fwd)
Sorry Dave, but your not correct in that statement.
When a length of wire is wound into a coil the resonance
That's why the so called quarter wave wire length stuff is
so WORTHLESS. Quarter wave resonance and a physical
Quarter wave are two different animals.
On Tue, 12 May 1998 11:41:11 -0600 (MDT) Tesla List <tesla-at-pupman-dot-com>
>---------- 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
>straight and in a vacuum with nothing else around it. As soon as you
>to coil the wire the resonance goes down.
>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
>>When Dr. Tesla made initial coil designs, he often resorted to
>>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
>>be used. Since, however I found that this is not neccessarily the
>>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.
>>quick experiments indicate that the coil geometry has alot to do with
>>ultimate resonant frequency apart from the length of the wire.
>>bizzare things happen when the aspect ratio is below 0.1.
>>According to conventional physics, (let me know if I missed
>>a charge and it's attendant feilds will propagate faster in a
>>than in a coil. It follows that the coil should always resonate lower
>>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
>>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
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