Analysis of the NVIS channel availability in the medium wave band

New digital radio systems in the medium wave band are emerging and they require accurate planning algorithms in order to improve QoS. In the MW band there is a lack of prediction parameters as regards the ionospheric propagation, especially for Near vertical Incidence NVIS sky wave. To do this, the NVIS channel features are provided in this paper, such as field strength variability and the time interval in which the channel is available. In addition the identification of the main reception impairments is also accomplished. An extensive measurement campaign has been carried out in Spain in order to exhaustively study and analyze NVIS channel availability in the medium wave band. Moreover, the stationary signal state is analyzed determining which is the optimum period to transmit this kind of signals during the nighttime.