Characteristic Wave Diversity In Near Vertical Incidence Skywave Propagation

In Near Vertical Incidence Skywave (NVIS) propagation, effective diversity reception can be realized using a dual channel receiver and a dual polarization antenna with polarization matched to the (left hand and right hand) circular polarization of the characteristic waves propagating in the ionosphere. This paper presents measurements on NVIS-signals received via ionospheric F-layer reflection using a dual circular polarization receive antenna, demonstrating a reduction of the fading margin by 8-11 dB over a single circular polarization antenna. The measurements where performed at a mid-latitude location in the Northern hemisphere, over a distance of 110 km.