Re: "Q" - weird... Not so high ??

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "boris petkovic by way of Terry Fritz <twftesla-at-uswest-dot-net>" <petkovic7-at-yahoo-dot-com>



--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
> 
> Hi Malcolm,
> 
> In this case,
> 
> The probe impedances were "fixed" to match an
> estimated streamer load from
> the coil.  The probe's load is fairly realistic for
> a streamer...
> 
> Cheers,
> 
> 	Terry
> 
> At 06:27 PM 3/9/2001 +1300, you wrote:
> >Hi Terry,
> >         Without looking at the traces:
> >
> >On 8 Mar 01, at 21:57, Tesla list wrote:
> >
> >> Original poster: "Terry Fritz"
> <twftesla-at-uswest-dot-net>
> >> 
> >> Hi All,
> >> 
> >> I was frequency sweeping my small coil's terminal
> voltage response and
> >> noticed something...  I am loading it with a 220k
> resistor and the 3pF
> >> HV (Tek 5100) scope probe.  I am driving the
> primary circuit from the
> >> wide-band low-Z amplifier.
> >> 
> >>
>
http://hot-streamer-dot-com/TeslaCoils/Misc/SmallCoilRvF/P3030001.JPG
> >>
>
http://hot-streamer-dot-com/TeslaCoils/Misc/SmallCoilRvF/P3030021.jpg
> >> 
> >> The frequency response of the small coil swept
> from 200kHz to 300kHz
> >> looks like:
> >> 
> >> http://hot-streamer-dot-com/temp/Tek00000.gif
> >> 
> >> Since the system has dual "humps", the "Q" is
> "weird"...
> >> 
> >> The center frequency is 229.8kHz and the two
> 1/SQRT(2) freqencies are
> >> at 216.5 and 242.5 kHz.  Thus the Q would appear
> to be only 8.84. 
> >> This system is not terribly far from a CW coil
> setup.  This would
> >> imply that CW coils have fairly low Q too!!  
> >> 
> >> Not the 100+ Q we usually assume for CW coils,
> but less than 10!?!...
> >> 
> >> Comments...
> >
---
Uh ,oh !Unloaded Q=10 ?!?
I think the conclusion is wrong,or something's  wrong
with that measurment setup whatever.
Unless,you used some "exotic" (and bad one) coil form
material unknown to me.
Don't know exactly what might be about nor I don't
have experience with CW coils,but Q=10 seems too low
to me.My opinion.


Regards,
Boris    

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