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Folded Resonator
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From: Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Monday, February 23, 1998 7:08 PM
To: Tesla List
Subject: Re: Folded Resonator
Hi Jim,
> From: Jim Lux [SMTP:jimlux-at-earthlink-dot-net]
> Sent: Monday, February 23, 1998 11:21 AM
> To: Tesla List
> Subject: Re: Folded Resonator
>
>
> >
> > ----------
> > From: Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
> > Sent: Sunday, February 22, 1998 4:52 PM
> > To: tesla-at-pupman-dot-com
> > Subject: Folded Resonator
> >
> > Hi all,
> > I wound a folded resonator in the weekend (expt #2). I first
> > I didn't measure Q because of interference from several powerful
> > transmitters in my home vicinity which made graticule readings
> > difficult to get to any degree of accuracy. However, it looked pretty
> > high (sharp tuning)
>
> Time to build that Faraday cage out of chicken coop wire to make those
> measurements in a quieter environment.... The aviary netting isn't ideal
> for shielding (because the wires go in and out of the inside, potentially
> carrying interference through the "wall") but I've had good luck in general
> with it. I built a bunch of panels out of wood 2x4's, stretched the chicken
> wire acrosss it, and lashed them together to make a "field reconfigurable"
> screen room for testing. Not as nice as the copper room I used to work in,
> but it attenuated the outside RF environment by some 50 dB (up to at least
> 30 MHz, anyway. After that it sort didn't work too well. Didn't do too
> great with 60 & 120 Hz either, but great for BC band stuff around 1 MHz).
I agree. Unfortunately, my house is bathed in kW of RF at several
different frequencies. The last time I did serious Q measurements was
in ferro-concrete surroundings during a semester break here at work.
I will have to wait for a suitable time to measure this one. In such
quiet surroundings with network activity and power usage at a minimum
I was able to measure Q's climbing towards 500 in small coils and 300
in a large one. I plan to test fire the coil this week if I can
string a suitable mica cap together for a small neon I have.
Malcolm