Azimuthal distribution of noise and interface at HF

The predictions of atmospheric and man-made noise in CCIR Reports 322 and 258 are for short lossless, grounded, single vertical monopole antennas, but practical antennas may differ from the CCIR reference antenna in many respects. The antenna directivity may be expected to affect both noise and spectral occupancy statistics. Experimental information on the effects of directivity on noise is scarce, and in some respects conflicting. Most previous spectrum occupancy studies have used omnidirectional antennas, but some results with directional antennas have recently been reported. The paper reports further measurements at a site in Southern England