This paper treat problems linked with radiated power and wall parameter measurements and its possible solution. Power measurements are easily done in a free-room without obstacles. Various obstacles located in the room and its possible movement to another place of location are distorting measurements. The paper contains several suggestions how to decrease these effects or to keep them in mind for interpretation of results. The objective of authors is associated with simulation of radiation from indoor that requires adequate models for walls of the room. Therefore spectrum analyzer is applied in addition to the power measurements to measure wall parameters too.