Abstract :
A theory that 56-megacycle transmission at a distance of 400 to 1200 miles takes place via sporadic-E-layer reflections has been investigated by comparing numerous reports of such reception with ionosphere data provided by the National Bureau of Standards. Simultaneous transmission conditions on lower frequencies are also considered. An indication is given of the necessary geographical separation of ultra-high-frequency transmitting stations, operating at the same frequency, to avoid occasional severe interference.
