Here are the angles you need to the satellites, of course a multi satellite will be pointing at a few satellites at the same time, but the below should help to see if you have a line of sight to the satellites individually.
Yorktown, VA 23690
Latitude 37° 13.722'N Longitude 76° 32.538'W
Sat Name Sat Lng Az(t) Az(m) El Skew
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*** Of Particular Interest ***
EchoStar 3 61.5W 156.0 167.2 44.0 -18.9
EchoStar 6 110.0W 227.5 238.7 34.5 36.0
EchoStar 8 110.0W 227.5 238.7 34.5 36.0
EchoStar 7 119.0W 236.5 247.7 28.3 41.6
EchoStar 5 119.0W 236.5 247.7 28.3 41.6
EchoStar 9/Telstar 13 121.0W 238.3 249.5 26.9 42.7
EchoStar 1 148.0W 258.5 269.7 6.0 51.3
EchoStar 2 148.0W 258.5 269.7 6.0 51.3
EchoStar 4 157.0W 264.2 275.4 -1.1 52.4
DirecTV 3 81.8W 188.6 199.8 46.5 6.9
DirecTV 2 100.8W 216.7 227.9 39.9 28.4
DirecTV 1R 100.8W 216.7 227.9 39.9 28.4
DirecTV 1 101.0W 216.9 228.1 39.8 28.6
DirecTV 4S 101.2W 217.2 228.4 39.7 28.8
DirecTV 6 109.8W 227.3 238.5 34.6 35.8
DirecTV 5 119.0W 236.5 247.7 28.3 41.6
Also Dishnetwork has a program you can download that will give you the angles for multi satellite systems like the Dish 500........
http://www.dishnetwork.com/content/products/installation/azimuth/index.shtml