In residential areas measurements are usually carried out at three locations, from which the antenna(s) are usually visible, namely on the same roof or at ground level close to the site, at an opposite building and at a nearby sensitive area of public usage (school, hospital, club, etc). In non-residential areas, motorways and installations inside buildings two measurement locations are chosen, one close to the station and the other at a nearby sensitive area of public usage, if any, or according to the requirements of the customer. At each location, the exact point of the maximum non-ionizing electric field is determined using a broadband probe, a spectrum analyzer and specialized software.
Subsequently, at each of the above points, electric field measurements are carried out at predetermined frequency zones covering the spectrum 30 MHz – 3 GHz, with the use of a spectrum analyzer controlled by appropriate software and of a tri-axis probe. Strict precautions are taken during the measurements to minimize the possibility of modifying the prevailing electric field, such as keeping a minimum distance of 50cm from any conducting material, using non-conducting supports (tripod, table etc), etc.
Measurements are carried out with a scanning period of 6 minutes (in accordance with standard EN50492), detecting for the GSM900 and GSM1800 bands the maximum value (peak detection) and the RMS value for the remaining bands, maintaining the maximum value of all scanning cycles in each band (max-hold), in accordance with standard EN50492.
Measurements for the trunked systems (GSM, UMTS, TETRA and LTE) are augmented by extrapolation to maximum traffic conditions in order to obtain the final measurement results, which represent the maximum possible field strength (worst-case scenario). The final results are always accompanied by the uncertainty of the measurements, which is calculated according to the EN 50492 standard.