The ionospheric propagation of radio waves of frequency 16 kc/s over distances of about 200 km

The detailed information previously obtained at Cambridge of the propagation of waves of frequency 16 kc/s over a distance of 90 km has been extended by investigation of distances up to 200 km. Measurement of phase, the essential feature of the experiments, was achieved by comparison with a reference signal sent from the trans mitter to the receiver by land line. Behaviour over the two ranges is much the same, the chief difference being that multiple reflections are more evident over the greater distance. The background common to this and companion papers is presented.