Wadley loop

The "Wadley loop" was mostly used in more expensive stationary radio receivers, but the "Wadley loop" was also used in a portable radio receiver (Barlow-Wadley XCR-30 Mark II).

Unlike other drift-reducing techniques (such as crystal control or frequency synthesis), the Wadley Loop does not attempt to stabilize the oscillator.

However, the drift makes it impossible to use high-IF selectivity to reject undesired signals.

Instead, it selects an entire band of signals - which one depends on which harmonic was chosen in part 3 above.

This can potentially be accomplished with a conventional superheterodyne back-end converting 3-2 MHz to 455 kHz and finally demodulating the signal back to audio.

When we're listening to a 30 MHz signal, this receiver is about ten times as stable as one using a high-frequency tunable VFO.

Although the knob moves in a continuous, analog fashion, its effect on the receiver operation is discrete, that is, the tuning advances in 1 MHz jumps.

An example is Yaesu's FRG-7 communications receiver,[5] which uses the system to remove local oscillator drift.