NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Determining noise temperatures in beam waveguide systemsA new 34-m research and development antenna was fabricated and tested as a precursor to introducing beam waveguide (BWG) antennas and Ka-band (32 GHz) frequencies into the NASA/JPL Deep Space Network. For deep space use, system noise temperature is a critical parameter. There are thought to be two major contributors to noise temperature in a BWG system: the spillover past the mirrors, and the conductivity loss in the walls. However, to date, there are no generally accepted methods for computing noise temperatures in a beam waveguide system. An extensive measurement program was undertaken to determine noise temperatures in such a system along with a correspondent effort in analytic prediction. Utilizing a very sensitive radiometer, noise temperature measurements were made at the Cassegrain focus, an intermediate focal point, and the focal point in the basement pedestal room. Several different horn diameters were used to simulate different amounts of spillover past the mirrors. Two analytic procedures were developed for computing noise temperature, one utilizing circular waveguide modes and the other a semiempirical approach. The results of both prediction methods are compared to the experimental data.
Document ID
19940025154
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Imbriale, W. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Veruttipong, W. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Otoshi, T. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Franco, M. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 6, 2013
Publication Date
February 15, 1994
Publication Information
Publication: The Telecommunications and Data Acquisition Report
Subject Category
Communications And Radar
Accession Number
94N29657
Funding Number(s)
PROJECT: RTOP 310-20-65-86-08
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available