Raymarine RL70 won't display speed

[kpetry]

My Raymarine RL70 in my new-to-me 340 DA will not display speed. The data box does show on the chart, the chart will "find ship" and display progress on the chartplotter, and the GPS fix is good with 10 satellites in use - just no speed numbers in that box. I've been all through my documentation, and can't find the fix. Any ideas? Thanks in advance! Kurt

 

[alnav]

I think you need to enable the data box called "SOG" - Speed over Ground. That is the speed parameter provided by GPS and, if the GPS is getting fixes, that parameter should be being produced. The "Speed" parameter you are probably looking at is generated from an external speed sensor such as a paddle-wheel or outdrive pitot sensor. You may or may not have either one of these but the SOG output will, in my opinion, be better.

 

[kpetry]

Makes perfect sense! I figured it was something simple. Thanks!