Uploaded May 2024 | Updated September 2026, 3 weeks ago

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This is my attempt at a variometer crystal radio. I'm not going to waste a lot of your time on this, it does not work well. 2 stations + a mixed medley. Still, maybe there's a brave experimenter out there who can see how to make to work well. If so, go for it and let us know!

MATERIALS ========================
This is the variometer 3D printer files (print at 50% size):
thingiverse.com/thing:6290893
Notes: This capacitor value for this radio is VERY fussy
Coil Outer: Dia: 43.615 mm, Turns: 36 = 18 x 2
Coil Inner: Dia: 35.76 mm, Turns: 32 = 16 x 2
- 330 pF capacitor
- Crystal earphone
- 10k to 40k ohm resistor
- 1n34a diode or D9K