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A serious problem affecting the local radio industry in Cyprus is radio interference from the Middle East. This problem is especially acute on the highway along the coast during the summer months because interference degrades the sound quality in vehicle receivers due to chirping noise, hissing, fading and distortion. During the last decade the issue was explored by monitoring the field strength intensity of unwanted signals with respect to atmospheric conditions that excacerbate interference. According to the research outcomes presented in this paper, severe interference occurs due to "Tropospheric Ducting", i.e., radio energy becomes trapped between two boundaries in the lower layers of Earth's atmosphere. Thereby, this phenomenon acts as a waveguide that favors radio waves to propagate beyond the horizon with very strong field strength intensity where under certain atmospheric conditions exceeding the expected free space theoretical value. Because the commercial Band FM is already oversaturated for years, it was considered important to expand this research to explore the impact of interference on the new digital DAB, DAB+ radio, that will soon be launched in Cyprus, as it is discussed below. [ABSTRACT FROM AUTHOR]

Due to the long distance propagation characteristics of the HF spectrum, noise and interference are significant and challenging factors that have to be addressed in the context of HF system performance. Both aspects exhibit systematic diurnal, seasonal, and solar cycle variability that result in a number of corresponding measurement campaigns all over the globe, in an effort to characterise HF noise. Noise at HF consists of man-made and naturally occurring HF noise with atmospheric and galactic components. An understanding of HF noise variation in terms of time, azimuth, and filter bandwidth is crucial for a specific location, as it can provide a background knowledge based on which appropriate values of HF system parameters may be selected. This paper deals with the temporal, azimuthal, and bandwidth characteristics of HF noise based on a one-month dataset of electric field strength measurements recorded by a directional antenna in Cyprus. [ABSTRACT FROM AUTHOR]

Interference from other users, due to the long-distance propagation of HF signals, causes spectral congestion, which is considered a primary detrimental effect on HF (3–30 MHz) communication systems. More than a year of HF electric field measurements from a calibrated monopole HF antenna collected by a dedicated measurement system installed in Cyprus have been used to compare neural networks and non-linear regression for the development of single-allocation congestion models in the HF spectrum. These models can be used to advise operators on typical interference spectral congestion levels and assist in the planning and management of frequency usage by assessing the interference level to alleviate spectral congestion in the HF band over Cyprus. The performance of these alternative modeling approaches is discussed in the context of their ability to successfully capture the diurnal variability of HF interference at a certain incident field strength threshold. [ABSTRACT FROM AUTHOR]