Hmmm, that's what I was thinking. I carefully followed the instructions - separation of the antennas and separation from the GPS. My Flarm antenna is very close to the aft edge of the glare shield, vertical, not touching, cable not routed near the dipoles, everything that was mentioned in the antenna supplement. I coiled up the extra antenna cable, maybe that's an issue? Sure would be nice to have some sort of quantitative measurement available so one could tweak without guessing.

you should be getting much better than 2 miles.