Red dots

Lynn Deffenbaugh


The red dot (there should only be one of them) indicates your projected position based on the most recent beacon that APRSISCE transmitted. The red dot isn't scaled to the map, but to the surrounding circle. In the Genius Beacon settings, there's a Forecast Error that defaults to 0.1 miles (1/10 mile). That distance is considered to the be radius of the circle. The red dot will range from the center towards the edge in the direction that your last beaconed heading and speed would place you. When the red dot hits the edge, if the Min Time has elapsed, a new beacon will be issued.

For instance, let's say your last beacon said you were going due East at 5 miles per hour. Right after that beacon, you increased your speed to 7 miles per hour. The red dot will start lagging to the west as you travel faster east than your last beacon would indicate. When the forecast lags by 1/10 mile, the dot will hit the left edge of the circle and a new beacon will be sent and the red dot will jump back to the center to be covered by your own icon.

If you turn slightly left or right, you will see the red dot slow start moving towards the edge as your current path veers away from where an extrapolated position would put you. Again, when it has seen an accumulated error of 1/10 mile (or whatever you have configured for the Forecast Error), a new beacon will be sent.

Hopefully that clarifies the mysterious red dot!

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile

PS. Sorry for the delay in answering this question. I received it while on vacation and am now clearing out that "ToDo" folder in my e-mail!

Jerome Lofton wrote:


Lynn what are the fast moving unmarked round red dots on the display?

Jerome Lofton, Jr.