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Rain attenuation is one of the main impairments that limit radio signals in high rain rate regions, especially at higher frequencies such as Ku, K and Ka frequency bands. Therefore, rain rate and rain attenuation predictions are some of the fundamental steps to consider when designing terrestrial line of sight communication links. The paper presents rain rates at 1 min integration for 0.01 percentage of time exceedance using Chebil, Lavergnat-Golé and power law conversion rain rate models for Akungba-Akoko, Ondo State, Nigeria. This was achieved using 5 min integration rainfall data for a period of three years. The rainfall data were measured by the Nigerian Environmental and Climate Observing Program (NECOP) instrumentation installed at the Adekunle Ajasin University, Akungba-Akoko. The estimated rain rates were used as input parameters to compute the total rain-induced attenuation at 0.01 percentage of time exceedance for 15 GHz, 23 GHz and 30 GHz through a path length of 10 km for vertical and horizontal polarizations, using Moupfouma, ITU-R and Lin attenuation models. Lavergnat-Golé conversion model gave the highest rain rate estimation in the region, while Lin attenuation model gave the highest estimation for total rain-induced attenuation, which is also closest to that of the ITU-R attenuation model. Generally, for all operating frequency bands and rain rates, the total rain-induced attenuation at horizontal polarization is higher compared to that at vertical polarization. Results from the analysis provide a broad knowledge of rain attenuation in the tropical region which can serve as a good preliminary design tool for terrestrial link engineers.

In the VHF band (30 MHz-300 MHz), radio propagation is usually by space waves, which consist of direct wave and ground-reflected wave. These radio signals are affected by the electrical parameters of the ground, curvature of the earth surface, height of the antenna above earth's surface and weather conditions in the troposphere. The electric field strength of radio signals decreases with increase in distance from the transmitting antenna. In this work, measurement of electric field strength of Frequency Modulated (FM) radio signals from Crystal FM, Minna, on 91.2 MHz and Power FM, Bida, on 100.5 MHz in Niger State Nigeria, was carried out in all the 25 Local Government Areas of the state. A Digital Signal Level Meter, GE-5499, covering the signal range of 30-120 dBµV, was used to measure the signals. The longitude, latitude, altitude and also distance from the reference point (i.e., location of the transmitting antenna) were measured at every location using a handheld Global Positioning System (GPS) receiver. The parameters obtained were used to determine the coverage areas of the two FM radio signals studied in Niger State. The results obtained showed that the configuration of FM radio transmitters in Niger State does not give optimum coverage of the State.

Studying atmospheric neutrino oscillations in the few-GeV range with a multimegaton detector promises to determine the neutrino mass hierarchy. This is the main science goal pursued by the future KM3NeT/ORCA water Cherenkov detector in the Mediterranean Sea. In this paper, the processes that limit the obtainable resolution in both energy and direction in charged-current neutrino events in the ORCA detector are investigated. These processes include the composition of the hadronic fragmentation products, the subsequent particle propagation and the photon-sampling fraction of the detector. GEANT simulations of neutrino interactions in seawater produced by GENIE are used to study the effects in the 1 - 20 GeV range. It is found that fluctuations in the hadronic cascade in conjunction with the variation of the inelasticity y are most detrimental to the resolutions. The effect of limited photon sampling in the detector is of significantly less importance. These results will therefore also be applicable to similar detectors/media, such as those in ice.