The detector is a Robinson limited oscillator with a single tuning control to which has been added an untuned ``transmitter'' coil orthogonal to the usual sample coil. Oscillation is maintained by a combination of Robinson feedback and weak mutual coupling of the two coils. The rf fields of the two coils are in time phase; the transmitter field is much the stronger. Dispersion signals were obtained in tests to 20 MHz at least as easily as were absorption signals with a conventional autodyne. The circuit is especially well suited to frequency‐swept searches for narrow, easily saturable lines (since the dispersion signal does not saturate) and those requiring highH1with unimpaired sensitivity (since the ``receiver'' sees the entire nuclear signal, but only a small fraction of the ``transmitter'' output).