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The testing of a new design high power S-band diplexer is reported. The megawatt Cassegrain diplexer (MCD) is to be used for DSN operations. The tests described were performed at 100 kW at the Venus Deep Space Station (DSS 13) transmitter test area. At 100 kW or less no degradation of receive performance was detected.
Continuing testing and refinement of the remote controlled, unattended automated pulsar observing station is noted, along with routine pulsar observations of 22 pulsars. Radar observations of geostationary satellite are discussed. Current status of the 400-kW X-band radar is reported along with routine automatic testing of the stability-reliability of the DSS 13 maser-receiver noise adding radiometer combination. A failure in the Faraday rotation receiving system is noted along with discussion in some detail of the activities of the high power transmitter maintenance facility. Continuation of receiver phase stability testing, specifically the effects of temperature on coaxial cables, is discussed and results reported. A demonstration at full power of the microwave power transmission facility is noted and routine support of the planetary radio astronomy experiment is discussed. Transmission of master clock synchronization signals to overseas DSN stations is also reported.
A sequential decoder was implemented in the DSS telemetry subsystem for the DSN MARK 3 data system implementation. This decoder performs the same decoding function as the data decoder assembly performs in the telemetry and command data handling subsystem. However, the new decoder is much faster, allowing potentially high data rates in the future.
The most significant Viking Mission events supported by the DSN during August and September 1976 are reported. Intermediate Data production and DSS support are also summarized for this period. Viking DSN Discrepancy Report activity for the period January 1975 through September 1976 is also included.
In projected very-long baseline interferometry (VLBI) work a reference point for 64-m antennas is the intersection of the elevation and azimuth axes. A minimum-level effort at DSS 14 to determine the magnitude of the effect of diurnal changes in the temperature of the alidade legs on the height of the elevation axis is described. The thermal expansion between the lowest recorded temperature -3 C (27 F) and the highest, 36 C (97 F), over the period covered was 8.9 mm (0.35 in.).
The Goldstone radar system at DSS 14 was used to probe the Martian surface at 8495 MHz in a narrow strip between -6 deg and -2 deg latitude. The Viking C landing sites lie in this strip, and their altitudes, rms surface slope, and reflectivity are presented.
Test results confirm that the Deep Space Station (DSS) and Network Operations Control Center (NOCC) processing of telemetry, command, radio metric, and monitor data with the existing DSN Mark III-75 configuration will be unaffected by the recent change of the Ground Communications Facility (GCF) high-speed data subsystem to a clock rate of 7,200 bits per second.
The phase characteristics and group delay of the S-band Megawatt Cassegrain Diplexer (MCD) and S-band Megawatt Transmit Filter (MTF) are reported. These phase measurements on the MCD and MTF were done in response to the need to obtain the total DSS hardware ground delay required for very long baseline interferometry and ranging radio metric measurements.
The design of a K-band radiometer for use in the microwave weather project is discussed. The major components of the system, such as feedhorn, waveguide switch, and receiver assembly are described. The system will be installed at DSS 13 at Goldstone, California, when completed.
Continuous sinewave interference effects on telemetry data obtained at the Goldstone Deep Space Station (DSS 11) were analyzed. The continuous sinewave interference is treated as an extraneous noise. Empirical telemetry data degradation and drop-lock models were then developed based on test data and certain physical characteristics of the telemetry data processing system. These models will be used as a portion of the radio frequency interference detection tools in the first version of the Deep Space Interference Prediction software.
Statistics listing the Deep Space Network tracking and command support and the discrepancy report status for 1 January through 28 February 1977 are presented in tables. The initial Viking extended mission period of normal DSN support, following the nonstandard operations during the solar conjunction period is included. Operational testing subsequent to the MK III data system installations at DSS 12, 44, and 62 during this period are also discussed.
The version of tutorial input implemented on the Modcomp used for antenna control at DSS 13 is described. Emphasis is on the use of the tutorial input; program operation is described to the extent that it makes the use more understandable. Flow charts are provided.
Modifications of the complex mixer system to increase bandwidth and number of channels were made. Three modified complex mixers were installed at DSS 14 and were used to process planetary radar signals in March and April of 1977.
A dual-directional loop coupler in WR 430 waveguide was installed at DSS 14 as part of the system to measure station range delay. This installation was necessary to provide special test translator signal injection ports for the Voyager near-earth calibration sequence, which required that the SPD maser be bypassed to prevent saturation of the receivers. The design of the dual coupler and testing of this device at high power is discussed.
The status of the Viking Deep Space Network Mark 3 '77 data subsystem implementation project and related testing at DSS 42/43 from 1 September through 31 October 1977 are reported. The Viking DSN discrepancy reporting system, Viking command support, tracking support, and periodic tests conducted with the Viking spacecraft are also discussed.
Radio science ranging requirements negotiated between past and present flight projects and the DSN have generally focused on just the DSS and spacecraft hardware. All elements in the end-to-end system are analyzed and considered in terms of the error hierarchy. The end-to-end system is defined and examined as it applies to the generation of radio science ranging requirements. The variability of the performance levels of the system elements is emphasized with respect to the radio science experiment being performed and the DSN-spacecraft frequency band configuration.
A selective repeat automatic repeat request (ARQ) system was implemented under software control in the Ground Communications Facility error detection and correction (EDC) assembly at JPL and the comm monitor and formatter (CMF) assembly at the DSSs. The CMF and EDC significantly improved real time data quality and significantly reduced the post-pass time required for replay of blocks originally received in error. Since the remote mission operation centers (RMOCs) do not provide compatible error correction equipment, error correction will not be used on the RMOC-JPL high speed data (HSD) circuits. The real time error correction capability will correct error burst or outage of two loop-times or less for each DSS-JPL HSD circuit.
The results of the S-band traveling wave maser phase delay stability measurements performed at DSS 62 are presented. These tests were required for the Pioneer-Venus wind experiment.