billbob, DonG and I put out 5 in a spread pattern about 20 feet apart. They were for learning how to use the HDS and HB SI/DI units, not for an active attractor. I plan to add to these this year and look at the fish since I have somewhat mastered the use of my HDS. billybob had the gps cords, and I could not find them for a year. ha.