2.2.2 spase://VSPO/NumericalData/ISIS1/SFS/AveragedIonongrams ISIS 1 Swept-/Fixed-Averaged Ionograms 2012-04-11T10:42:31 This data set consists of ISIS 1 (International Satellites for Ionospheric Studies)ionograms that have been obtained through a data restoration project. The ISIS ionograms, consisting of a fixed-frequency and a swept-frequency part, were digitized from the original ISIS telemetry tapes. The digitized sounder data consisting of 8-bit receiver-amplitude values collected at a 40 kHz rate contain the time and the frequency associated with each sounder pulse. The frequency of each sounder pulse is determined from a 3rd degree interpolation between the times of the frequency markers as identified in the sounder video during the A/D operation. Included in this data set are the average-resolution ionograms (averages of each 4 successive 40 kHz 8-bit values) in CDF format. Software to read and display the individual CDF files is available at ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/isis/software/ These CDF files were produced at NSSDC from the original PI-provided ionogram data. Other ionogram data sets available at NSSDC include the full resolution ionograms and average ionograms both in the PI-provided (OS2) binary format, ASCII header files with pass-specific information and the PCM data which contain header, time, AGC, frequency-marker information and telemetry-level data from all other ISIS instruments. The binary average ionograms and the ASCII header files are available online at ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/isis/topside_sounder/ ISIS 1 and 2 data are available to the extent permitted by telemetry scheduling and the location of telemetry stations. A list of stations can be found at http://nssdc.gsfc.nasa.gov/space/isis/isis-table1-new.html and their location on a worldmap is shown in http://nssdc.gsfc.nasa.gov/space/isis/isis_station_lar.GIF ( spase://SMWG/Person/Robert.F.Benson GeneralContact info about the digitization project http://nssdc.gsfc.nasa.gov/space/isis/isis-status.html spase://VSPO/NumericalData/ISIS 1/SFS/AveragedIonongrams spase://SMWG/Repository/NASA/GSFC/SPDF Online Open FTP access to files at SPDF ftp://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder FTP repository of ISIS-1 Topside sounder ionograms from multiple telemetry stations HTTP access to files at SPDF http://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder HTTP repository of ISIS-1 Topside sounder ionograms from multiple telemetry stations CDF spase://SMWG/Repository/NASA/GSFC/SPDF Online Open CDAWeb http://cdaweb.gsfc.nasa.gov/sp_phys/ I1_AV_ALL ISIS 1 ionograms data with subset, plot, list functionalities from CDAWeb Text spase://SMWG/Instrument/ISIS1/SFS Waves.Active 1969-01-30T14:50:12 1983-12-30T15:19:33 Earth.NearSurface.Ionosphere