Recently, near field wireless sensor network advanced miniaturization by a λ/4 antenna and a pattern antenna, and is expanding to enviroment monitor systems. But, transmitted signal strength is kept below 10 mW in general in order to achieve low power consumption, therefore optimn setting is difficult to general users. This paper assumes that construct network (2.4GHz and 920MHz) on rivers and lakes surface, and consider radio wave propagation on water face of between terminals having pattern antenna.