This new VFO Circuit is a two part (two board) system for the experimenter. The "Bottom Board" (photo) is the PLL and VFO, complete with an area for the experimenter to add whatever circuit he desires such as a transmitter, receiver, transceiver etc.. The "Top Board" is a controller with a keypad for frequency entry and an LCD digital readout that displays frequency. The Top Board controller communicates with the MC145170 chip. Boards may be stacked with spacers and can be mounted in a project box. Not intended to be a complete kit, this circuit pair is intended to provide a highly flexible platform for the experimenter, student or Ham radio builder etc.

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The circuits provide Rock-Solid frequency control with a very easy to use human interface (that's fancy for push-bottom keypad and readout). Included are circuit ideas, in schematic form, including a forty-meter transmitter and a radio receiver circuit. The prototyping area is large; the user can build a simple or multi-stage AM or FM receiver, CW rig, signal generator etc. The circuit may be used with various oscillator designs from 440Khz to 185Mhz. The circuit employs an MC145170 PLL IC which provides drift-free tuning with considerable stability.Operates on 12 volts DC. You will need up to 100mA to power the kit plus don't forget to add enough current capability to handle your own addition to the PC board.