Southworth (1945) and Reber (1944) were the first to measure radio noise from the quiet Sun. Southworth (1945) showed that the radio diameter of the Sun was larger than the optical diameter using a 24 GHz experimental radar at Bell Labs. During the second world war in 1942 radar systems accidentally detected solar radio bursts associated with the large solar flares (Hey, 1946). The influence of solar emissions on wireless communications and other radio systems has been studied since the early 1980s (Barron et al., 1985, Castelli et al. 1973).
Bala et al. (2002) analyzed four decades of solar radio bursts data compiled by the National Geophysical Data Center (NGDC) of the National Oceanic and Atmospheric Administration (NOAA), Boulder, CO, in the context of noise levels in contemporary wireless communication systems. Various solar radio observatories around the world measuring the solar radio bursts during 1960-1999 contributed to the NOAA data.
