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An experimental investigation of the changes of VLBI time delays due to antenna structural deformationsStructural deformations primarily occur as functions of antenna elevation angle due to gravity loading. For a Cassegrain antenna, one of the major effects of structural deformation on measured VLBI time delays are those delay changes associated with axial subreflector displacement from its nominal position. Two types of time delay changes that occur when the subreflector is axially defocused are: a change which is a linear function of subreflector defocus position; and a cyclical change caused by multipath. Test results show that for the 64-m DSN antenna, the linear change is 1.8 times the subreflector defocus position, while the peak-to-peak change in cyclical variation is about + or - 3 cm when a spanned bandwidth of 38 MHz at 2290 MHz is used.
Document ID
19820017219
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Otoshi, T. Y.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Young, L. E.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 10, 2013
Publication Date
April 15, 1982
Publication Information
Publication: The Telecommun. and Data Acquisition Rept.
Subject Category
Communications And Radar
Accession Number
82N25095
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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