2.2.0 spase://SMWG/Instrument/Alouette2/SFS Alouette 2 Sweep-Frequency Sounder Topside Sounder 2019-05-05T12:34:56Z The Alouette 2 Sweep-Frequency Sounder measured the ionospheric electron density in the altitude range 300 to 3000 km, and extended the Alouette 1 measurements to higher altitudes and to a different period of the solar cycle. The ionosonde was a radio transmitter that recorded the time delay between a transmitted and returned radio-frequency pulse. A continuum of frequencies between 0.12 and 14.5 MHz was sampled once every 32 s. The Alouette 2 sounder also provided greatly improved observations of plasma resonances. Several virtual-range (delay-time) traces resulting from ground reflections, plasma resonances, birefringence of the ionosphere, nonvertical propagation, etc., were normally observed. spase://SMWG/Person/Donald.B.Muldrew PrincipalInvestigator NSSDC's Master Catalog https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1965-098A-01 Information about the Sweep-Frequency Sounder on Alouette 2 Sounder Sweep-Frequency Sounder on Alouette 2 spase://SMWG/Observatory/Alouette2