Coaxial connector to pin
I don't know DirecTV, but since you're talking about a dish I presume it outputs RF signals, which go to your radio receiver to be demodulated to audio. You can't sample that with Arduino's ATmega 328 ADC: its bandwidth is only 38.5 kHz typical, which is suitable for sampling audio, but not RF.
Overmore, the output level will be much too low for the ADC.  

If you would want to cut off the connector from the cable, and connect that to your PCB, use a terminating resistor that matches the cable's characteristic impedance, typically 50 &Omega; or 75 &Omega;.