ITU-R REPORT BS.303-3 PDF

Introduction

One of the primary requisites for establishing the limits of power for sound broadcasting is the determination of the value of the signal-to-noise ratio required for satisfactory listening in the absence of any other interference. Availability of reliable noise data is, therefore, necessary. In most of the countries in the Tropical Zone, which are either underdeveloped or developing and where man-made noise is comparatively low, atmospheric radio noise is the principal source of interference in band 7 (HF).