
Also known as chirpsounder
250px|thumb|right|Typical ionogram indicating an [[F2 layer critical frequency (foF2) of approximately 5.45 MHz.]] thumb|right|An example of an ionosonde system displaying an ionogram
250px|thumb|right|Typical ionogram indicating an [[F2 layer critical frequency (foF2) of approximately 5.45 MHz.]] thumb|right|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 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.
60 mapped locations
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).