Radar reading backwards.

[Randolph]

Radar/plotter RDP-139
While i was at sea my radar started reading backwards not matter witch way I turn. Turned it off. Disconnected power but still backwards. Plotter on same unit working fine. Any ideas

 

[Flatline]

Randolph,
Thank you for your inquiry.
without knowing all of the details my guess is that the RDP139 was somehow reset to the original factory defaults. The defaults for this would set radar antenna to type "B" which may or may not be the type of antenna actually being used (the RDP was common display used for several different model radar/plotters). This might explain why it suddenly was 180 degrees misaligned. You made need to simply go into the installation menu and select the correct radar antenna type. You'll find the table which specifies the antenna type and correct corresponding A,B,C, etc letter type on page 3-5 of the installation manual. https://www.furunousa.com/en/support/RDP139