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Spectrogram plots in GIF format derived from Voyager 1 Planetary Radio Astronomy (PRA) Highband receiver daily files during Jupiter Encounter (1979-02-01 to 1979-04-13). These plots are available for both polarization channels and in both color and grayscale. The color scale of these plots represent the electric field power spectral density in units of millibels. Across the top of each spectrogram in the spacecraft and instrument name, the name of the binary data file that was used to create this plot, the polarization channel (Left or Right) and the date in the format YYMMDD. The data set provides 48 second resolution highband radio mean power data in units of millibels. The high-band receiver consisted of 128 channels of 200 kHz bandwidth each, with center frequencies spaced at 307.2 kHz intervals from 1.2 MHz to 40.4 MHz. The highband receiver was designed especially for the observation of Jovian decametric radio emissions. The PRA radiometer was usually operated routinely in the so-called POLLO sweeping mode, in which all 198 frequency channels of the high- and low-band receivers together were swept in 6 sec, dwelling at each channel for 25 msec. From one step to the next in the channel switching sequence, the antenna polarization sense was reversed, i.e., was changed from RH to LH or vice versa. Thus the time required for making a measurement of both the RH and LH intensity components at both senses of elliptical polarization at a given frequency was 12 sec. The data consists of successive averages of 4 pairs of RH and LH intensity measurements, each average spanning an interval of 48 sec. The data are calibrated and are given in units of 'millibels' which is 1000 times the log of the received power. Zero millbels corresponds to approximately 1.4 x 10^-21 W m^-2 Hz^-1, however, this value is never seen in practice. The minimum values detected, which includes receiver internal and spacecraft generated noise, are about 2300 to 2400 millibels, or about 3.5 x 10^-19 W m^-2 Hz^-1; even higher values are seen at the very lowest frequencies. Note: The polarization indicated is the received polarization, not necessarily the emitted polarization. Correct interpretation of the received polarization depends on the antenna plane orientation relative to the radio source. A good description of this concept can be found in Leblanc Y., Aubier M. G., Ortega-Molina A., Lecacheux A., 1987, J.Geophys. Res. 92, 15125 and in Wang, L. and Carr, T.D., Recalibration of the Voyager PRA antenna for polarization sense measurement, Astron. Astrophys., 281, 945-954, 1994. and references therein.