Do any of you have any tips for sharing NMEA
data over a network using UDP protocol in Windows (beyond what's in the OpenCPN
online user manual)?
I tried it yesterday, but met with very frustrating results. I was using a brand new travel router (Zyxel MWR102
) fresh out of the box. I connected my tablet and netbook to it by WiFi
, and within OpenCPN
3.3.1606 I quickly set up UDP (with output box checked) at 192.168.100.1:9247 on the tablet and did the same thing (but without output box checked) on the netbook. Since I was not on the boat
, I used the VDR plug
in to send out the NMEA
sentences from the tablet and it worked! The NMEA debug window showed data going out and coming in as expected, and the "ownship" icon and AIS
target icons all showed up perfectly.
Then I realized that a couple things were not "optimal" with my setup. Port 9247 is normally used for GPSD, so I changed the port to 10110 on both computers
. Also, I had the priority for the UDP ports
higher than incoming COM and TCP instruments (even though those were unchecked), so I lowered the priority for the UDP connections. Also, there were some auto-updates of Windows 8 on the tablet and of AVG on the Netbook that occurred during the test. I am not sure which of these changes caused the things to break, but it stopped working. And nothing I did could get it to work
again. I went about "undoing" all the changes that I had made, with dozens of reboots of both OpenCPN and the OS on both machines. But nothing could get it to work
like it had originally. OpenCPN's NMEA debug window still shows the sentences going out on the talking machine (tablet), but OpenCPN on the receiving machine (netbook) shows nothing coming in. I tried running TeraTerm on the netbook to see what is coming in, but it supports COM and TCP only - not UDP.
Can any of you offer clues to what is wrong here? Do most routers restrict what ports
can be used for specific protocols? Would Windows firewall (or the router) have detected unusual activity and shut down the port without warning? Since multiple reboots of the computers
did not work, should I reset my router to factory default settings to eliminate any port mapping that might me interfering?
The most frustrating part of this is the "quick and dirty" setup worked right away. It only broke after I tried to "clean things up" with proper port number and priority.