Hey. We have encountered a connection issue where the heartbeats are really unstable. In BlueOS the heartbeat is lost every other second. This means we cannot really arm it or controll it with a controller, because it will disarm every time the connection is lost. SSH connections are still stable and the camera does not lag either. By listening to the heartbeat messages, we can see that they arrive in bursts instead of continuously. The issue came very suddenly and everything was working indoors before we encountered the issue on the shore. We cannot think of anything we did out of the ordinary before going out to sea deployment. Has anyone else encountered and fixed the issue with heartbeats arriving in bursts?
Hi Zukane -
It sounds like your tether may be damaged. Try installing the tether diagnostic BlueOS extension, and sharing a screenshot here of the page it produces once it is loaded. You could also run a network speed test and share those results.
Finally, if those results look ok, try updating to the latest BlueOS Beta, and going to Mavlink Endpoints (in pirate mode), an enabling Mavlink Server at the top… see if that helps!
Hi @Erlingns95,
There are some interpretation guidelines in the Extension README 
From the images you shared, it looks like one of the wires in your tether pair is likely broken/disconnected. If your tether has multiple pairs you could try to switch to a different one, or if you want to continue investigating the issue you could try measuring the resistance/continuity of each wire with a multimeter, and/or making sure the twisted pair is fully plugged in to the Fathom-X module at each end, and inspecting the length of your tether for any nicks or cuts that may have damaged one (or more) wires.
P.S. I’ve edited your post so your images are embedded, so others don’t need to download PDF files to see them
Thank you oh so much, Eliot.
You are 100% correct, and this helped tons.
I note your P.S. about the photos and will have it in mind for next time.
There definitely will be a next time!