Ionosonde

Typical ionogram indicating an F2 layer critical frequency (foF2) of approximately 5.45 MHz.
An example of an ionosonde system displaying an ionogram

An ionosonde, or chirpsounder, is a special radar for the examination of the ionosphere. The basic ionosonde technology was invented in 1925 by Gregory Breit and Merle A. Tuve[1] and further developed in the late 1920s by a number of prominent physicists, including Edward Victor Appleton. The term ionosphere and hence, the etymology of its derivatives, was proposed by Robert Watson-Watt.

  1. ^ F.C. Judd, G2BCX (1987). Radio Wave Propagation (HF Bands). London: Heinemann. pp. 12–20, 27–37. ISBN 978-0-434-90926-1.{{cite book}}: CS1 maint: numeric names: authors list (link)