Signal Polarizations in the VHF and UHF Broadcast Spectrum

Accurate field intensity measurements require inclusion of the contribution of all wave polarization components. This paper presents the results of horizontal and vertical plane field strength measurements for the purpose of assessing the importance of measuring both components in routine environmental field monitoring. Results show that FM broadcast stations may have vertical plane field strengths 5 dB greater than in the horizontal plane but that VHF TV stations exhibit vertical fields typically 20 dB lower while UHF TV stations showed typically a 14 dB lower vertical field component. Based on these measurements made over a period of approximately a month, it is concluded that accurate exposure determination in the FM band requires making both vertical and horizontal field measurements.