Detection of solar radio brightness oscillations with 160.01-min period from direct measurements

It is shown that direct measurements of the quiet Sun brightness at 8.2 and 13.5 mm wavelengths corrected for extinction in the Earth atmosphere by means of the Bouguer law reveal the 160.01-min periodic component. The relative amplitudes of variations are of approximately 6x10-4 at the shorter wavelength and of 10-3 at the longer one. The brightness maximum coincides with the phase of the maximal radius of the photosphere as derived from the optical data