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24 Hr Electric Spectrum Analyzer Survey Plots on Microfilm


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

Time span: 1977-10-22 to 1987-12-31


This data set consists of experimenter-supplied survey plots on microfilm. Each plot displays 24 h of data from the ISEE 1 University of Iowa Gurnett Plasma Wave Experiment electric spectrum analyzer (ESA). The top line on each plot contains letters indicating which of four antennas is connected to the electric spectrum analyzer. For the ESA plots, V is Heppner's 215-m long wire antenna; U is Mozer's 73.5-m double antenna; S is Scarf's 0.61-m short electric dipole antenna; and B is the Z-axis search coil magnetometer. The second line indicates the geocentric radial distance of the spacecraft in earth radii. The third line (immediately above the data) and the line immediately below the data indicate universal time in hours and minutes. Orbit parameters are included in the electric spectrum analyzer plots. The date and start time of each plot are given on the left side of each plot, along with the geocentric solar ecliptic coordinates at the start time. The ESA consists of 20 channels covering the frequency range from 5.6 Hz to 311 kHz. The channels are logarithmically spaced with four frequency channels per decade. The center frequency of each channel is indicated on the left side of the plots and the channel number is indicated on the right side of each plot. The bandwidths of the channels below 10 kHz are about + or - 15% of the center frequencies, and the bandwidths for the 10 kHz and higher channels are about + or - 5% of the center frequencies. The outputs from the spectrum analyzers are voltages approximately proportional to the logarithm of the field strength with a dynamic range of about 110 dB. The baseline of each channel is at about 0.1 microvolts/m. On the plots the vertical lines represent the geometric mean of all the data points in a 114-s time interval. The solid line above the average data represents the peak value observed over the same interval of time. The graph for each channel runs from 0.00 to 5.12 volts. Full scale (5.12 V) represents a signal strength about 110 dB above the baseline level. Each plot has been made from the raw data and has not been calibrated. Known errors and interference have been removed with one exception: when the experiment is turned off (which may happen during special tests or near perigee on shadow orbits) all channels read about one half of full scale.

Alternate Names

  • 24-Hr Elec Spec Analyzer Plts,Flm


  • Space Physics: Magnetospheric Studies
  • Space Physics: Heliospheric Studies


  • 77-102A-07D

Additional Information



Questions and comments about this data collection can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Dr. Roger R. AndersonGeneral ContactUniversity of
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