Pointing accuracy and electrical performance of Kashima 26 m antenna, obtained from radio astronomical observations.
Abstract
We have measured pointing accuracy and the electrical performance of the Kashima 26m phi Cassegrain antenna by means of radiometric observation of cosmic radio sources at the frequency of 4.2 GHz. There are four causes of instrumental errors in pointing of the antenna of an azimuth-elevation mount. We have obtained the following values of the errors. These are (1) a deviation of the azimuth axis direction from zenith, 5.8 millidegrees, (2) nonorthogonality of the azimuth and elevation axes, 5.0 millidegrees, (3) nonorthogonality of the antenna-beam axis and elevation axis, -5 millidegrees, and (4) gravitational deflection of the antenna structure, 0.42 millidegrees/deg. in elevation angle. The decrease of the antenna gain at low elevation angle is a few percent in every polarization, and half power beam width (HPBW) shows almost no change in any elevation and azimuth angle, but fairly depends on polarization.
- Publication:
-
Radio Research Laboratory, Journal
- Pub Date:
- April 1974
- Bibcode:
- 1974RaRLJ..21..543K
- Keywords:
-
- Cassegrain Antennas;
- Error Analysis;
- Instrument Errors;
- Performance Prediction;
- Pointing Control Systems;
- Radio Astronomy;
- Antenna Design;
- Antenna Radiation Patterns;
- Azimuth;
- Calibrating;
- Polarization Characteristics;
- Position Errors;
- Power Gain;
- Astronomy