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2N2/40 Prototype RIT

Side view picture of the new prototype 2N2/40 RIT circuit. The diode in the foreground has been replaced with a MV209 varicap to provide up to +/- 2KHz of receiver offset tuning. Lesser amounts of offset can be obtained by adjustment of the trimmer toward the rear of the board. With the 1N4004 diode shown, about +/- 1KHz of offset is available.

Rear oblique view of RIT showing offset span trimmer. The circuit is built on a 1 X 2 inch single sided PC board substrate using "Manhattan Style" construction, as used in both of K8IQY's 2N2/40 rigs. True to form, the transistor used is a 2N2222. What else could it be in this rig!

Another rear oblique view. Five connections are required for operation; two to the adjacent main tuning potentiometer, and three to the 2N2/40 main board. A center detent potentiometer will be used in the final model.

This is the schematic of the 2N2/40 RIT circuit. While I claim no title to the origin of the circuit, the values shown are unique to the 2N2/40 implementation. The circuit was modeled using Electronic Workbench before it was built, to verify proper circuit operation.

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