TMA dot stack display
 

On the TMA display (US), at the top of the dot stack display are two numbers, -n and n. Would someone explain to me what those numbers mean? They change depending on the zoom level of the bearing line display. But I've not found a clear explanation of the the numbers.


TIA

I checked out the manual to try and confirm but it doesn't seem to say. I think they represent degrees of bearing, as in the solution says it should be here (on the line) but your dot is off by 0.5 degrees. Either that or some form of error or standard deviation. Honestly, it doesn't really matter (don't at me :D). It's just worth noting that when you zoom in you can see more of the "error" in the dots in the stack, which can be too sensitive and cause you to spend too much time refining the solution.

That's sounds plausible. Thanks.

The numbers are supposed to show "bearing error" so they would be in degrees. :yeah:

Keep in mind, the dot stack shouldn't look like a straight line. You can't "dial in" accurate enough numbers to form a perfect solution and it wouldn't hold up with that kind of accuracy, anyway. You never hear "Helm, steer 256.837 degrees, make turns for 6.235 knots". :03:

Use the dot stack for what it is. You input a contact's course, speed, and distance then watch how it works out over time. Its also handy for spotting a contact changing course or speed.

Thanks. That's good to know.