An investigation of the propagation of radio waves at frequencies in the VHF and UHF bands within certain British cities

[摘要] Unmodulated carrier waves at frequencies of 75.375, 85.875, 167.2 and 441.025 MHz have been radiated by aerials mounted on tall buildings or prominent terrain features in the British cities of Birmingham, Bath and Bradford. The spatial distribution of the r.f. signal envelope existing within urban and suburban areas at these frequencies has been recorded using a vehicle-mounted receiver with a aerial fixed to the vehicle's roof. An analysis of these measurements has shown the distance over which the envelope may be anticipated to be Rayleigh distributed to be less than 75 m. A median signal prediction model is derived from the measured data and its performance is statistically assessed with the experimental values. The measurements and the predictions have been found to be·in close agreement. Comparison of the Okumura model with measured values has demonstrated that the proposed model exhibits similar prediction errors to those obtained by the more widely used Okumura model. The Okumura model is therefore concluded to be more complex, and hence more costly to use, than is necessary for applications in British cities.

[发布机构] University:University of Birmingham;Department:School of Engineering, Department of Electronic, Electrical and Systems Engineering

[关键词] T Technology;TA Engineering (General). Civil engineering (General)