We observed a total of 14 Mira variables as well as 4 late type variable stars for their SiO ν=1 ν=1 , J = 2 - 1 maser lines from April 1989 to November 1990 with the 13.7 m radio telescope at Daeduk Radio Astronomy Observatory. The maser intensity variations were the prime objective of the observations which well covered the periods of the variations. The origion of the variations were studied by comparing wi th those previousely measured in optical and infrared(IR) wavelengths and we confirmed that the intensity variations were in good correlation with those in V magnitude and IR intensity as previousely found in former investigators in general. However, for a few sources, we could find the missing maxima. The intensities themselves also were in good correlation with SiO ν=1 ν=1 , J = 1 - 0 maser intensities observed in Yebes as expected. The good correlations indicate that the pumping source of the SiO maser is likely to be the IR emission in the masing regions and the "missing maxima" that are apparent in two particular sources are considered to relate wi th the strength of shocks arising from the eruptive mass-loss from central stars.

We determined the efficiencies of the aperture. beam and forward spillover and scattering of 13.7 m radio telescope at Daeduk Radio Astronomy Observatory through the observations of the planets and Moon. The main panels adjustments were carried out on September 1991 and the improvements in the efficiencies were checked by comparing the observations made before and after the panel adjustments. The efficiencies were turned out to be 0.35, 0,47 and 0.83 at 115.27 GHz for the aperture, beam and forward scattering and spillover. respectively. These marked nearly a factor of two upgrade of the efficiencies previously measured.