Citation
Abstract
An experimental investigation was conducted on the 64-m antenna at DSS 14 to study the effects of antenna structural deformations on VLBI time delays at S-band, Structural ' 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 dis_ placement from its nominal position. Two types of time delay changes that occur when the subreflector is axially defocused are (1) a change which is a linear function of subreflector defocus position and (2) a cyclical change caused by multipath, Test results showed 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 +3 cm when a spanned bandwidth of 38 MHz at 2290 MHz is used.
Details
- Volume
- 42-68
- Published
- April 15, 1982
- Pages
- 8–16
- File Size
- 769.8 KB