Engineering topics

Franco, M. M.

Publications and source records attributed to Franco, M. M..

25 records · Page 2

NASA NTRS1982

K sub A-band weather-dependent system performance estimates for Goldstone

A K sub A band atmospheric noise temperature and attenuation statistical model is developed for Goldstone, based on water vapor radiometer measurements at 31.4 GHz made during winter and spring 1981. An equivalent X-band model is derived from these measurements, and the two sets of data are compared to determine the possible advantages of developing DSN telecommunications links at 32 GHz. For a nominal elevation angle of 30 degrees and identical antennas, it is found that a K sub A band system at Goldstone will show a 5 to 1 dB signal-to-noise ratio advantage oer an X-band system more than 99 percent of the time.

Clauss, R. C.↗

NASA NTRS1982

X-band noise temperature effects of rain on DSN antenna feedhorns

Simulated rain tests were carried out to determine the noise temperature contribution of liquid water adhering to the aperture cover material on both a standard DSN X-band feedhorn and on an S/X-band common aperture feedhorn. It was found that for the particular common aperture feedhorn tested, system noise temperature increases were much greater when the plastic horn cover material was old and weathered than when it was new. The age and condition of the aperture cover material is believed to be a major factor in the amount of degradation experienced by a telecommunications system during rain events.

Slobin, S. D.↗

NASA NTRS1981

The 20.7- and 31.4-GHz atmospheric noise temperature measurements

The 20.7/31.4-GHz water vapor radiometer was used for atmospheric noise temperature mesurements. Tipping curve data and on/off Sun data are compared. During the time of the data collection (7:00 a.m. to 12:20 p.m.), the sky was clear and the ground temperature and humidity varied from 14 C to 24 C and 65 percent to 51 percent respectively. The tipping curve data is felt to be the most accurate.

Slobin, S. D.↗

NASA NTRS1981

Some 20.7- and 31.4-GHz solar disk temperature measurements

The performance of a 20.7/31.4 GHz water vapor radiometer was evaluated with respect to its use in measuring atmospheric noise temperature. Results are in good agreement with the results previously reported at the same frequency.

Franco, M. M.↗

NASA NTRS1981

X-band atmospheric noise temperature statistics at Goldstone, DSS 13, 1979 and 1980, and clear air noise temperature models for Goldstone

Superhigh frequency (X band) noise temperature data are presented which illustrate the noise temperature increase above quiescent baseline for the years 1979 and 1980. Clear air models are also given which shows the seasonal noise temperature effects of changing surface water vapor densities for a particular atmospheric model.

Slobin, S. D.↗

NASA NTRS1981

Portable zero-delay assembly

Instrument is calibrated using back-to-back method. In comparison standard, S-X isolators are opposite from device being tested to permit signal flow in reverse direction. After calibration portable zero-delay assembly (PZDA) is used to set time delays of deep-space network ground-station ranging systems. Approach is also used to calibrate microwave links in other communications systems.

Franco, M. M.↗

NASA NTRS1979

X-band atmospheric noise temperature data and statistics at Goldstone, DSS 13, 1977 - 1978

Sample data and cumulative distributions of atmospheric noise temperature increase above the quiescent baseline for the calendar years 1977 and 1978 are presented. Comparison is made with the existing Deep Space Network noise temperature statistics.

Slobin, S. D.↗