We made a pyramidal horn antenna system for 21cm cosmic radio wave. The antenna system has a rectangular waveguide with TE10 mode and a copper probe to detect the electromagnetic wave in waveguide. The parameters of the probe are obtained by experiments using two waveguides. Pyramidal horn antenna is designed to get a gain of 20dB. The size of the aperture of this horn is 94cmX74cm. The beam width of half power is about 14.7degree for the frequency of 1.4GHz. The horn is made of aluminum plate with a thickness of 2mm. The signal from horn and waveguide is amplified in a receiver system and is converted into DC in the detector. The intensity of the signal is recorded on a chart recorder. We observed the sun using this simple radio telescope and obtained the brightness temperature of 2.2X10^5K, which indicates that the sun is quiet at 21cm.
Publication of Korean Astronomical Society
- Pub Date:
- December 1993