User manual LOWRANCE 1240A

[. . . ] If the "U" bracket is too long, it can be cut to the desired length with a saw. Before mounting the control, clean the mounting surface for the control decal. Remove the paper backing from the decal to expose the adhesive and place it over the control's mounting location. Mounting hardware for the control, consisting of two nuts, lockwashers, and flat washers are supplied in the hardware pack. [. . . ] For instance, as the water depth goes from 90 to 110 feet, you will see the bottom signal on the dial move past the "zero" signal to the 10-foot mark. Thus, on the second revolution, depths of 100 to 200 feet can be read by adding 100 feet to the reading on the dial. If you're in doubt about the depth, turn the unit off until the scan disc stops. Turn it back on and watch to see if the bottom signal completes one revolution before stopping. If the signal travels around the dial two times, the water depth is the depth shown plus 200 feet. Turned fully counterclockwise, it's at minimum and the only signal that will appear on the dial, (unless it's in extremely shallow water) will be the constant surface signal at "0". Turning the knob clockwise will increase the receiver sensitivity and weaker echoes from deeper water shows on the dial. For example, if you are in 10 feet of water and the sensitivity control is at minimum, you will see only the "0" signal. As you turn up the sensitivity, a signal appears at 10 feet on the dial. As it's turned up more, this signal will get wider and other smaller signals from fish (if present) appear between 0 and 10 feet. Remember that the true depth is always the shallowest edge of the bottom signal, NOT the middle. As you turn the sensitivity up more, another signal appears at 20 feet on the dial, double the depth of the first signal. It's caused by the sound waves hitting bottom, bouncing back, hitting the surface of the water and then bouncing down to the bottom and back again. Always set the sensitivity to return a steady bottom signal, regardless of depth. To show fish, adjust the sensitivity to show a second bottom signal, when possible. SUPPRESSION Use suppression to reduce or eliminate false flashes on the dial caused by electrical interference or cavitation on the transducer. This is the normal position for trolling as it gives the highest resolution (ability of the sonar to separate targets such as fish that are close together or near the bottom). The knob in the "pulled-out" position gives the best interference rejection which is usually required when operating at speed. Because of the type of suppression circuity used by Lowrance, the unit's sensitivity is not affected. (Sensitivity in a sonar unit is measured by the instrument's ability to read at depth plus show details. ) A small amount of resolution will be lost when engaging suppression. Note that suppression can be engaged by pulling out on the sensitivity knob at any time. Fits 3 3/8" diameter mounting hole Maximum outside diameter 4" Depth behind mounting surface 4 5/8" Weight: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0-60 ft - 60 pps 0-100 ft - 24 pps Pulse Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] REMINDER: You must retain the sales slip or sales receipt proving the date of your original purchase in case warranty service is ever required. This warranty does not apply to any database or its contents supplied initially with this product. For warranty information on the databases and their contents, please refer to the "Databases Limited Warranty" included with this product. Only We back your investment in quality products with quick, expert service and genuine Lowrance® replacement parts. [. . . ]