I am tweaking my dish , and , when searching for a known good transponder , I was unable to get a signal , even knowing I was in the right spot. After much frustration , and , without moving the dish , I found , by trial and error , that , I had to go to another tp and back to the one I was looking for . just moving the dish would not show a signal. This is true for all sats. This is a strange one for me . Using a 2100 motor 39" dish , and an S9 receiver. Other than that , all works well. When all is set up , there is no issue changing channels or sats. I hope I explained it well. Any ideas ???