Height according to the articles seems to vary, I think I've read 150 feet. The detectors seem to be the same.

I can't find any of these community advisories from anytime prior to 2011. It seems these test were reported in local muncipal type papers/radio last summer. Each advisory reads almost identical, as if its a canned SOP memo posted.

I would imagine there are probably other things going in the open, but gone unnoticed. I see where these similar sorties were carried out in 1987 in Russia after Chernobyl. I am out of my element, to draw any reasonable sensible conclusions as to what this means, there is no point, at least for me. But it's worth noting, because it may very well be a key element to an ongoing plot synopsis. By itself it means nothing..with two or three other characters...worth watching