Abstract
Development of relay SFN is a important subject for the introduction of DTTB in Japan. In relay stations, the coupling disturbance from transmitting antenna to receiving antenna is a severe problem. To know how coupling conditions change throughout thc year, measurements in two relay stations, their output power is 100W and 10W respectively, have been continued In September, very large fluctuation of 10dB was observed at the relay station while typhoon was visiting. From these measurements, we find that weather conditions influence the state of the coupling.
