In Ireland (and Spain), there are — strictly speaking — two American satellites above the horizon (i.e. you can point your dish at them in the sky), both of which carry the U.S. networks: Echostar 3 at 61.5°W (carries all the networks except NBC and FOX) and DirecTV 1 at 72.5°W (carries all 7 networks).
Both these satellites, HOWEVER, have "footprints" which are solely focused on North America and so anyone able to point their dishes at these satellites across the Atlantic in Europe will still have a problem, because he or she is "out of footprint"; in fact, way out of footprint!
Having said that, this doesn't mean that it is still not theoretically possible to pick up the signals from those satellites, but it would require a VERY BIG dish, meaning probably anywhere in the range of, say, 10 to 50 meters in diameter, could even be bigger than that (or it could be smaller!). No one knows yet, or at least I don't know yet. It would be really interesting to know just how big a dish was needed in, say, Ireland (or Spain/Portugal) or at least to know if it was possible with a < 10 m dish (It has been reported that Echostar 3 has been received in Iceland [with a 5 or 6 m dish?], and in Tenerife (Canary Islands) with a 2.4 m dish, both places nowhere near the "official" footprint.).
Could I pick up anything from the U.S if I had a 3m dish? I have a clear view straight across the atlantic.
In that case, then you are most likely able to point your dish at another satellite, Nimiq 2 at 82°W, as well (it's just above the horizon). If U.S. TV is what you're after, then this satellite is perhaps the most interesting proposition. It's a Canadian satellite andit has all 4 major U.S. networks on board— in High Definition! (It also carries Discovery and NFL Sunday Ticket – again, both in HD!)
However, as with the other two satellites, you are still way out of footprint! But since this satellite is further west, it looks down onto its target – i.e. the continental U.S. (and Canada) – at a different angle than its neighbour satellites to the east, such as Echostar 3, which means that if both satellites have similar footprints, then the one which is further west is more likely to spill over to the east, i.e. towards Europe, or at least that is how I see it somehow. :-shifty So, again, I think it would be interesting to see just how big a dish were needed to catch this bird as well as all the other CONUS birds to the east of it.
But don't get me wrong here, don't go off and buy a huge 5-10 m dish straight away, for starters those big antennas are bl***y expensive! And also I do wonder if it isn't possible to just measure the raw signal coming off the satellite first using a "small" dish and then calculate/determine what size of dish would be needed. Maybe some expert could elaborate more on that.
If it's any help I'm in Northern Ireland and I was able to pick up Fox, AXN, Fox life, CNBC on Hispasat, crystal clear with an 80cm dish, then they switched encryption to Nagravision 2, so now I can just get Fox and Foxlife. Even though they are nearly all American shows, (Joey, Ally McBeal, Law and order, Lost etc) it's on the Portuguese network TV Cabo. They are all in English with Portuguese subtitles, with no American adverts or news programmes. It is basically 1 show after another, which is great, when there are 5 episodes of The Simpsons in a row for the kids, (I have to watch them, just to make sure there are no rude words), LOL. Saying that now, these channels are subscription only, they are not free.