> First thing I thought was "Oh man I want to put it in the lake near me and see if I can't get it detecting fish or something!" Same. Although my first effor

> First thing I thought was "Oh man I want to put it in the lake near me and see if I can't get it detecting fish or something!" Same. Although my first effort with my hydrophone (in my parents pond) was stymied because they live on a main road and all I picked up was car vibrations. Maybe that's your solution - get a fish tank/pond and hydrophone!