It sounds like you are watching DirecTV using an RF cable with your TV set tuned to channel 3 or 4 analog. That's about the only way you would see snow on the TV. If your receiver has an HDMI output, connect that to your TV and change your source to HDMI. At the very least connect the composite video (yellow) and stereo audio (red and white).
Listed in order of best to worst picture:
HDMI (Digital. One cable for both video and audio)
Component (Analog. Three cables for video, two for stereo audio)
S-Video (Analog. One multi-pin cable for video, two for stereo audio)
Composite (Analog. One cable for video, two for stereo audio)
RF (Analog. One cable for both video and audio)