Experimental and Theoretical Studies on Communicable Distance for Medical Telemeters between Hospitals Located with a Distance of 1,300 Meters

In Japan, medical telemeters managing patients' biological information via electromagnetic waves have been widely used. However, electromagnetic interferences caused by the electromagnetic waves emitted from telemeters in distant hospitals are an issue of major concern. In this study, we focused on two hospitals which are located 1,300 meters apart and had previously experienced interferences. We thus measured the electromagnetic waves emitted from a telemeter installed in one of those hospitals. Based on the estimation from theoretical equations in which loss of the electromagnetic waves due to the structural objects between the two hospitals taken into account, we found that it is possible to detect electro-magnetic waves even at a distance of 121.6 meters. We then deduce that extraordinary propagation due to such as tropospheric reflections might cause the interferences (electromagnetic wave propagation) emitted from medical telemeters even at a distance of 1,300 meters.