[gnormhurst]

Pay attention to your "optics". On the playing field there is IR everywhere. We used crossed polarizers as an adjustable filter to try to reduce the sensitivity to reflections, and we narrowed the opening of the heat shrink tubing. We used 3/8" tubing shrunk down to 1/8" just at the end of the tube. Then we finally were able to discriminate beacon from reflection.

As a point of reference, Tom Watson (of IFI?) at the Phila. regional had a controller set up as an IR tester. Using a naked (no optics) IR sensor, and standing behind the control station tables maybe 25' from the playing field, he could pick up the beacon on the far side of the field, as well as register the nearer beacon (that was facing away from us), presumably as a reflection off of something.

If your machine drives off into the sunset instead of to the beacon, you are plagued with reflections!