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		RS Theremin

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	Updated 07.04.08 Making the ideal theremin Antenna L4 = Century Extension Spring C-253 $4.97 usd 9/16" x 16-1/2" x .054" (14.3 mm x 419.1 mm x 1.372 mm) Bar Code 3859? 00253 - Sales #60954 Note: Use an AM Radio ferrite rod antenna for L3 which is wound with Litz wire. This will give the best results for linearity! The distance from the LC tuner to the Lev Antenna spring must be slightly more than 6" (15 cm). Photo of My Setup
Note: Use a spring coil stretch of 1/2" to 3/4" for linear octaves.
Features: Your normal pitch or "null" adjuster allows you to narrow the octave width to match the size of your hand for aerial fingering. The C4 connection must be directly to the hot end of your pitch coil which should be a direct connection to the transistor collector with no inline capacitor or choke interference. Note: C4 should turn freely with a plastic knob on it. What works best for initial tuning is if you temporarily mount a 12" nylon tube over the C4 shaft so your hand can remain away from the densest part of the theremin pitch field. Then push your knob back on and mark the location for future reference. LINKS is short for "Linear Ideal Note Key Spacing". When LINKS is achieved your theremin notes will match the piano keyboard key for key spacing from C1 to C4 with A2 at 16" (40.6 cm) distance from the antenna. (Three Octaves) .
Materials for the Lev Antenna Century Extension Spring (This is the Antenna) C-253 $4.97 usd 9/16" x 16-1/2" x .054" (14.3 mm x 419.1 mm x 1.372 mm) Bar Code 3859? 00253 My Lowes still had this as of July 2008 for $4.97 The actual length of the spring coils is 15.75" (40 cm) at 16 turns per inch (approx. 252 turns at a ½" diameter) Try Home Depot on the nut & bolt isle near the metal rods - I found my spring in Lowes near the nylon bolts. 5' PVC pipe 1/2 x 5' 98 cents - Use the full length of the PVC until your ready to mount it. This way you can stand it on the floor while experimenting. Use an alligator clip connected to the brass screw on the Lev Antenna that holds the spring in place. I would also recommend 5' PVC pipe 1/2 x 5' High Pressure PVC which can be found in the plumbing section of a hardware store. This has a slightly larger inside diameter and will fit snugly over the coupling nuts used on the EtherWave Standard elbow antenna fitting. Use a 1/2" (ideal) to 1" stretch on the spring in the PVC pipe as seen in the picture to the left next to the brass screws. This gives you about 15 turns per inch. To much stretch the outside low octaves could become "narrower" than the inside high note octaves. Hold your un-stretched spring next to the PVC pipe to get your screw markings. The distance from the LC tuner to the Lev Antenna spring must be slightly more than 6" (15 cm). Otherwise they will have unwanted interference between them. You need two 1" brass screws and nuts to hold the spring stretched in the PVC pipe, or use two 2" brass screws and have your spring mounted on the outside of the PVC. "With Lev tuning it is possible that before tuning, the octave next to the antenna will be wider than the outside low octave, this is one of the interesting antenna phenomenon's."
Ace Hardware Outlet CENTURY SPRING C-253 CENTURY SPRING EXTENSION SPRING 9/16 OD 16-1/2 Length .054 Wire diameter 25.2 Maximum deflection 61.7 LBS maximum safe load Steel Open wound helical

The Whisper "True beauty is hidden in Simplicity" from Nov. of '03
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