W/T 1920s to 1950s

© RN Communications Branch Museum/Library

The Ionosphere

(See the Post WW1 Years 1920s file - The Post WW1 years - the 1920s)

  The 1931 version of the Admiralty Handbook for W/T had got to the Heavyside Layer, only considering what went on in that layer both day and night without considering what might be going on 250 miles above the earths surface. The original name for the ionosphere (1902) was the "Kennelly-Heavyside Layer" named after the two British scientists who discovered this ionised layer, and they were stimulated by the successful transmissions made across the Atlantic by Marconi in 1901. They knew that the least height above sea level before ionisation took effect was approximately 60 miles although it wasn't 'set in stone' and was known to vary between day and night, summer and winter. What follows is the Royal Navy's state of understanding in the early 1930's 1930 EM Waves Part 1 and 1930 EM Waves Part 2