Radio radius and the brightness distribution of the solar disk at the wavelengths of 6.3 and 8.6 mm

The results of measurements of the radio radius of the Sun and of the brightness distribution over the disk of the ''quiet'' Sun, obtained at the RT-25X2 radio telescope simultaneously at the wavelenghts of 6.3 and 8.6 mm, are presented. The wavelength dependence of the radio radius of the Sun in the 4 to 8.6 mm range is obtained and the limb effects at 6.3 and 8.6 mm are estimated