Frequency-selective analysis of the isotropic behaviour and measurement uncertainty of the field strength measurement system Field Nose

A rigorous analysis of uncertainties involved with frequency-selective field-strength measurements of the radio frequency emissions from mobile communications base stations using the innovative Field Nose system is presented. The analysis is based on measurements and numerical simulations. The contributions from antenna patterns, antenna factor calibration, test receiver calibration, temperature coefficients, standing waves and cable losses are considered. An expanded uncertainty (k=2; 95%) between 2.9 dB (80 MHz) and 2.3 dB (2.5 GHz) is found. The most important uncertainty contribution at lower frequencies (<900 MHz) is standing waves. At higher frequencies the isotropy becomes significant.