#Long delay radio echoes probe free

Shortwave frequencies that are used do not penetrate the earth’s ionosphere, they are reflected back to earth which is what makes them useful, and if this had not been the case Jorgen Hals would not have been able to hear the primary signal or the 1/7th second echo. There are problems with moon bounce as an explanation even for this specific incidence of long delayed echo. This corresponds fairly well to mean distance between the earth and moon which is 238,855 miles. In three seconds, a radio signal would cover a distance of 558,000 miles, or could make a round trip of 279,000 miles.

#Long delay radio echoes probe free

The 1/7th second echo corresponds well with the earth’s 24,902 mile diameter since light travels at 186,000 miles per second in free space, very slightly less than that in air, and the path taken around the world involved multiple hops between the ground and ionosphere so it was not entirely straight.īut that does not explain the three second echo. However, in addition to this regular echo, Jorgen Hals also heard an echo of about three seconds in duration.

This represents the time it takes the signal to go around the earth once using multiple hops between the ground and the ionosphere. With shortwave broadcasts it is not unusual to hear an echo with a delay of about 1/7th of a second. This phenomena was first experienced by a Norwegian radio engineer, Jorgen Hals while listening to a Dutch shortwave station. Long delayed echoes refer to a radio phenomena where an echo of a transmission is heard that is longer than can readily be explained by most known origins, most typically 3-40 seconds.