BOM

Most of the parts are easily available on Digikey. However, dual concentric encoders and 5 digit 7 segment displays are hard to come by, so I've had to use more unusual suppliers. If these parts are no longer available, it will probably require some re-design. The encoder for the com knob slides in and out to provide the frequency step adjustment, and the enclosure fits around the encoder quite precisely. Also, it is unlikely that a different 7 segment display would have the same pinout, which would require changes to the PCB.