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Atmospheric Propagation Spectral Amplitudes (Digitized)


Availability: Data Identified but not Received


This collection consists of digitized microfilm frames containing printouts of processed digital data obtained from the Deep Space Radio telemetry and then supplied to the PI for the Atmospheric Propagation Experiment for the four Probes of the Pioneer Venus mission.

The printouts of the processed digital data are contained in five notebooks labeled 13-17 inclusive. Notebook 13 contains files marked Box 1 through 5 inclusive. These boxes designate the boxes of punched cards that were produced when the PI read the printed lists (from the telemetry) in order to make these digital data manually. In the notebooks the data are in printout form. These in turn were microfilmed and made available from NSSDC in that format as collection PSPA-00235. Formats are given early in Notebook 13 where the original lists are included. These are labeled in decibels and are just as the PI received them from NASA-JPL in their original form. Notebooks 14 through 17 are labeled "Probe Spectra", and there is one notebook for each of the four Probes: Large, Small Day, Small Night, and Small North. In each case there is a large body of 1,024 numbers packed together in a 32x32 array of 4-digit codes. Each array represents the spectrum of signal-plus-noise for 10 s as derived by John Armstrong. Each set of four digits gives amplitude in thousandths of decibels. The data are based on the open-loop recordings from Deep Space Station 14. The absolute level is arbitrary. The first value is the Ground Received Time in UT seconds; second value is the amplitude estimate in decibels and is based on power measured in the in-phase and quadrature channels with the center frequency of the filters guided by a phase lock loop. Next, the date-time group is given, followed by the number of points (1,024) and the bandwidth (1017.5 Hz). On the next line is given the time of year in seconds. Users of these data are advised to contact John W. Armstrong at JPL. Results from these data are found in "Surface reflections of Pioneer Venus Probe radio signals," Geophys. Res. Letters, 7, No. 7, pp. 521-524, 1980.

For this digitization effort the NSSDCA scanned the source microfilm collection PSPA-00235 at a resolution of 400 dots per inch and output each frame as one TIFF file. The NSSDCA also combined the TIFF images into one multi-page PDF file to facilitate browsing. Both formats are included in this collection.



NameRoleOriginal AffiliationE-mail
Dr. John W. ArmstrongData ProviderNASA Jet Propulsion
Dr. Thomas A. CroftGeneral ContactSRI
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