I'm posting this not without a very specific reason. A few days ago one of my friends accomplished something quite amazing: he "dived out" a 250m tall chimney of an abandoned factory. By "dive out" I mean: flew inside a chimney at its base, climbed 250m up inside the chimney and then flew out. Simple, right? Well, no :) Just think of it like this: how to get a solid video link when TX is 250m away inside a structure made from reinforced, thick, concrete?

I'm waiting for a video of "dive in" for sure!