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Sweep-Frequency Ionograms on Microfilm


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1962-09-29 to 1970-11-30


This data set, prepared at the Communications Research Centre in Ottawa, Canada, consists of Alouette 1 ionograms on reels of 35-mm microfilm. These ionograms are reduced data plots showing as a function of frequency the echo time delay (virtual range) of pulsed radio signals. They are an original form of the data prepared directly from the telemetry tape. The data are as complete as permitted by the limitations of spacecraft power, lack of onboard tape recording, telemetry station location, telemetry station scheduling, and data processing facilities. The data coverage is primarily near the 80 deg W meridian for periods of time up to 7 h per day. Since only time is noted on each ionogram, position and other related data must be obtained from world maps (NSSDC data sets included under 62-049A-00). A program for the reduction of topside ionograms to electron density profiles is available from NSSDC.

Alternate Names

  • Sweep-Frequency Ionograms, Mfilm


  • Space Physics: Ionospheric Studies


  • 62-049A-01A

Additional Information



Questions and comments about this data collection can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. George Leroy NelmsData ProviderDefence Research Establishment
Dr. Joseph W. KingGeneral ContactRutherford Appleton Laboratory
Mr. L. W. MillerGeneral ContactNational Oceanographic and Atmospheric Administration
Dr. J. H. WhittekerGeneral ContactDepartment of Communications/Communications Research Centre
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