Here is where we hope to answer many of your questions on the basic M1 (model 1) single channel System

What is the M1 side scan sonar? The M1 (model 1) true side scan (imaging) sonar is a single channel inexpensive system built around a consumer based marine echosounder. The basic package includes a towfish with imaging transducer, 100 ft tow cable, inline weatherproof microcontroller box, echosounder controller with b&w 480 x 480 pixel display, recordable media card and GPS receiver. The unit transmits pulses in a fan shaped beam to port which is narrow side to side (aprox 1.8 degrees) and wide top to bottom ( aprox 30 degrees, or aprox 60 degree depending on transducer chosen). In conjunction with the microcontroller this beam shape will register one "scan line" of an image per pulse with each succesive pulses until an entire image is recorded. The image data can be stored as a scrolling image on the supplied media card which can also store embedded GPS coordinates and other data. When played back on your laptop or PC you need only click on the displayed image file to retrieve GPS for boat position as well as your slant range (read as "depth") to target. Images recorded to the media card can be colorized and enhanced.

Performance The basic M1 can be used effectively in water depths from 10 to 200 feet with the shallower depths requiring calm water. This covers most coastal areas as well as most fresh water lakes, ponds, rivers etc. Search ranges are 60, 100, 150, 200, 300, 500, 800, and 1000 feet. Objects in the longer ranges will produce weaker echos depending on water conditions and target density. Optimal transducer beam angle to the side is adjustable by loosening a stainless nut and rotating the towfish relative to the cable mount.

Recording times

For 128 Megabyte media card. Recording times are aproximate and at full resolution and ping / chart speed.
60 ft range--2hours 22min
100 ft range--2hours 22min
150 ft range--2hours 42min
200 ft range--3hours 58min
300 ft range--7hours 14min
500 ft range--11hours 45min
800 ft range--14hours 27min
1000 ft range--19hours 52min
256 megabyte cards also useable to effectively double recording length