Citation
Abstract
The natural radio-source antenna-temperature data acquired by both the arrayfeed compensation system (AFCS) and the deformable flat plate (DFP) system at 32 GHz (Ka-band) during the experiment conducted during the winter of 1998-1999 to compare the performance of the two systems at DSS 14 are analyzed and final results obtained in the form of aperture-efficiency-versus-elevation curves. Particular attention is given to analyzing the noise and pointing characteristics of the two systems and the impact of these characteristics on the results obtained. Comparisons are made of the results obtained with the two systems with earlier Ka-band and 8.4-GHz (X-band) efficiency measurements at DSS 14 and with theoretical computations based on finite-element model predictions and holography measurements. Excellent agreement has been achieved with all of these approaches, with the result that the Ka-band performance of the 70-m antenna, both with and without compensation for the effects of gravity deformation, is now well understood. The uncompensated Ka-band aperture efficiency at the mean rigging angle of 41.5 deg is 31.0 +- 1.5 percent, while the gain improvement resulting from the two systems, each acting alone, ranges from approximately 2 dB at low elevations to between 2.7 and 4.4 dB at 85 deg, the higher value corresponding to the AFCS measurements.
Details
- Volume
- 42-139
- Published
- November 15, 1999
- Pages
- 1–29
- File Size
- 1.1 MB