The Noise-like Character of Solar Radiation at Metre Wavelengths

Abstract

Thermal radiation received from the sun at radio frequencies is indistinguishable from fluctuation noise in the radio receiver. However, the enhanced radiation often encountered at metre wavelengths is unlikely to have a thermal origin and hence may not be noise-like in character. This paper describes an experiment in which enhanced solar radiation on 85 and 60 Mc/s. was compared with receiver noise and with a C.W. signal by comparing the outputs from a diode with variable bias. This should detect any marked difference in the distribution of amplitudes of the fluctuations in solar and receiver noise. It was found that the enhanced solar radiation was indistinguishable from receiver noise.