Clegg Interceptor Dial

The Interceptor's dial used two frequncy readout scales which effectively increased the size of the dial significantly. 100 KHz marks are along the bottom of the dial. Lines representing 10 KHz run horizontally across the dial. Diagonals connect the 100 KHz points. The received frequency was then interpolated by reading the point where the dial pointer crosses a diagonal line. In the case of this particular dial, the frequency is .312 with the MHz delivered by the bandswitch. Since the bandswitch is in the 144 MHz position, the actual frequency reading would be 144.312 +/- a KHz or two. This was acceptably accurate for most purposes and far more accurate than other VHF receivers. The numbers on the circular dial in the window are simply a logging scale.

This same technique would have been useful for moderately priced communications receivers where the dial was not linear. The dial could be expaned vertially to produce an easy to read 1 KHz readout.