SNR Measurement of Ionospheric Channels for Availability Evaluation under NVIS Propagation

High frequency (HF) radio communications are used to transmit information over long distances. Since they are generally limited to narrow bandwidths and low transfer rates, techniques must be investigated to improve the capacity of HF communications. Estimating the signal-to-noise ratio indicates the reliability of the link between transmitter and receiver. In the design of adaptive systems, SNR estimation is commonly used to measure channel quality. This paper aims to present SNR variations over different time periods for ionospheric radio channels under Near Vertical Incidence Skywave (NVIS) propagation conditions using software defined radio (SDR) platforms.