The oscillator of the figure has its frequency determined by the crystal. The indicated value is 4.5 MHz, but crystals in the range 100 kHz to 10 MHz can be used. The output signal frequency, which may be a harmonic of the crystal frequency, will be tuned to L1 / CV. The coil L1, coiled over L1 for signal coupling must be calculated to obtain the desired impedance. Equivalent transistors such as the MPF102 may be used and the 10 nF capacitor must be ceramic. Changes in supply voltage can be made with 100 ohm resistor value change.
