I recently took the time to replace a non functioning vhf on the bridge and to add a second chartplotter station. While I was at it, I decided to crest a NMEA o183 network so that position data shows up on the vhf screen and DSC data shows up on chartplotter screen. After a fair bit of reading, I thought I had it figured out. Ordered the parts I needed and went at it. Happily, on the first try, I had position data showing on the vhf screen. Unfortunately, the position data on the vhf differs from the chartplotter position data by 60s N and 92s W. Although this is likely better info than I could communicate in an emergency situation, I find it curious that it is different. Has anyone experienced this? Do I have one of the wired crossed or something? Would love to fix it if possible. thanks.