I Googled 2YCFGY coax and found a loss of 27 db per 100 meters at 850 MHz. It didn't list the loss at higher frequencies, but the loss will be much higher in the 950 to 2150 MHz range that you are using.
This loss is higher than even RG59. At 850 MHz RG59 is about 25 db per 100 meters and RG6 is about 20 db.
Can you move your receiver to the dish and test it there with a short piece of RG6 cable? If that works OK, then better cable is probably your answer.