THEORY OF OPERATION
Your depth sounder works on the sonar principle. The control head generates an electronic signal which is coupled to the transducer where it is changed to an ultrasonic signal. This signal travels through the water until it hits an object or the lake bottom. The signal is then reflected back to the transducer, where it is changed back to an electronic signal.
The control head measures the amount of time it takes the signal to travel from the transducer to the reflecting object and back again. This time is then converted into feet (since the signal travels at a constant speed - approximately 4800 feet per second), and the number of feet to the object is indicated on the calibrated dial with the spinning lamp. The lamp revolves around the dial once for each 120 foot reading on the 120 foot units and once for each 60 foot reading on the 60 foot units. Therefore, the motor in the 120 foot unit rotates at 1200 rpm and in the 60 foot unit 2400 rpm. The motor in the Super Thirty II unit also travels at the speed of 2400 rpm. This is accomplished by the use of an integrated circuit signal processor which permits a 30 foot readout to be displayed on a unit running at the speed of a 60 foot model.
YOUR TRANSDUCER
The transducer is the transmit/receive "antenna" of your depth sounder. The transducer converts an electrical signal from your instrument into accoustical energy which is then transmitted through the "eye" of the transducer into the water. The return signal (echo) excites the "eye" with an accoustical shock wave and causes the transducer to send an electrical signal back to your instrument. The "eye" of the transducer is the flat portion that is focused downward into the water. For maximum efficiency the transducer's "eye" must not be obstructed and it must be in intimate contact with the water ("wetted'').
It is suggested you keep the face of the transducer clean. This can be done with soap and water.
NOTE: In order for your Humminbird to perform at Its maximum potential, care should be taken to Install the transducer properly. This Is the most critical part of the Humminbird Installation. Please read the following sections thoroughly and follow the installation instructions carefully.