The Mode S thing for your PC (I assume SBS-1 from Kinetic Avionics) picks up the same stuff that TCAS receivers get (the squitter transmission - which a Mode S transponder puts out every so often unprompted). You should get some basic information on the display and you could always send it back if the level of detail isn't enough. But just think. If it is mandatory in London airspace you're going to pick up a hell of a lot of planes in europe because they're probably fitted up for going into London. If you do buy one you'll be able to link into the world databse of Mode S soon anyway and watch Mode S worldwide. Apparently.....
And all because they put a Mode S on my helo and I wondered what the hell it was for!!!
