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VLF Spectrograms, Low-Resolution on 35-mm Paper


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

Time span: 1964-11-10 to 1965-12-15


This data set consists of VLF spectrograms, produced by Rayspan equipment, on 39 100-ft reels of 35-mm positive photographic paper, showing time of signal occurrence vs frequency of received VLF signals. Relative signal intensity can be qualitatively judged only by contrast between the background and the signal traces. These data are records of signals received by the 0.3- to 12.5-kHz broadband receiver and transmitted in real time when the satellite was in range of a telemetry station. They represent all VLF broadband observations made prior to December 15, 1965. Subsequent observations have not been processed and/or released by the experimenter. These are low-resolution data, having been photographed with low paper transport speeds. A primary use for this data form is in identification of data that may provide interesting cases to study with high-resolution processing of the same data. The original tapes and processing at various transport speeds are available through the data set contact, Dr. J. Katsufrakis, at Stanford University. Since only time is noted on the sonograms, satellite position and other related information must be obtained from world maps (see data set 64-054A-00C).

Alternate Names

  • Lo-Res VLF Spectrogrms,35mm Paper


  • Space Physics: Ionospheric Studies


  • 64-054A-08A

Additional Information



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



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