Jingquan Cheng [1]
January 10, 1994
Keywords: antennas, slant axis antenna, fast switching
The slant-axis antenna is being considered as a possible antenna for the NRAO MMA. For MMA phase calibration in the presence of atmospheric path length fluctuations, the ability to switch the antenna pointing rapidly between the source and a known calibrator may be extremely important. Because of its low moment of inertia, and because the structure is inherently very stiff, the slant axis antenna may be particularly advantageous in this respect. This memo describes some simulations of fast antenna switching using a computer model pf the slant-axis antenna. The time dependant structural displacements have been analyzed. There are two main effects: pointing errors and dish deformation. The conclusion is that the major problem is the pointing errors, resulting from oscillatory movements of the secondary mirror support.
[1] NRAO/TUC
Last modified: 09 December, 1999
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