Niks, judging from that report, it looks like your antenna isn't high enough.

Look at the "Path" column and you'll see what I mean. All the American stations are "2Edge" and "Tropo", as opposed to "LOS" (line of sight), meaning that the signal is either diffracted or you have to hope for a bounce off the Troposphere to get a picture.

Try running the re-running your report, but this time increase the antenna height 5 feet. Keep re-running it in 5 foot increments until you get to the point where the american stations are at least "1Edge" (best would be LOS). That will give you a good idea of how much higher you need to raise your antenna to get a picture that doesn't drop out on you. Hope this makes sense..