Directional observations on delayed signals on an ionospheric forward-scatter circuit

A study has been made of delayed signals reaching Slough from a transmitter at Gibraltar on 37Mc/s in the winter of 1956¿57. The mean bearing of the first signal to arrive after that due to ionospheric forward-scatter was found to vary between 250° and 290° during the day; the spread of energy in bearing is also considered. It is shown that the radiation from the transmitter aerial must be stronger to the west than to the south. Results for the second delayed signal are also given. Round-the-world echoes were occasionally observed, but these did not arrive from the direction of the great circle containing Gibraltar and Slough.