Typically, a picture that is 180 degrees out indicates that an incorrect antenna type is selected. Verifying radar type and performing a possible heading adjustment is what you need. To get into the installation mode, press and hold the MENU button down while powering up the display until the picture of the boat appears. The boot process will continue and come to a startup mode selection page...choose the default, installation mode. When the display has fully booted up, press MENU-System Configuration-System Setup-Installation Setup, choose Radar Setup and verify the radar antenna type is set to B for the 1734C. If it is, then press the Next Page soft-key and choose Heading Adjust...follow the on-screen instructions. If the antenna type was not correct, change it to B and power the display off and back on again. Check to see it the picture is aligned properly now. If needed perform a heading adjustment to fine tune the display picture.
NOTE: We suggest performing the heading adjust function when out on the water with buoy or marker that's easy to "see" on the radar screen so that it's easier to verify proper adjustment.