2.2.0 spase://SMWG/Instrument/Alouette1/SFS Alouette 1 Sweep-Frequency Sounder Topside Sounder 2019-05-05T12:34:56Z The Alouette 1 Sweep-Frequency Sounder measured the ionospheric electron density in the altitude range 300 to 1000 km. The ionosonde was a radio transmitter that recorded the time delay between a transmitted and returned radio-frequency pulse. A continuum of frequencies between 0.5 and 12 MHz was sampled once every 18 s. 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=1962-049A-01 Information about the Sweep-Frequency Sounder on Alouette 1 Sounder Sweep-Frequency Sounder on Alouette 1 spase://SMWG/Observatory/Alouette1