Media Network Long Delayed Echoes

First broadcast in 1984, this programme looks in some detail at a mystery that took decades to solve. Light and radio waves travel 7 times around the world in one second. So how can you explain some echoes noted on early shortwave broadcasts from PCJ, sometimes of several seconds? Did the ionosphere have a memory? Was the sun part of the equation? Unashamedly specialist this one. But we got good response from those interested in the technical aspects of shortwave radio.