Our digital cable signal has been getting worse over the past month. Last Monday, it got to the point that even the analog channels were glitchy. So Adam unconnected all the cables and brought our little TV and the digital box into the laundry room to determine if it was a problem with the cable inside or outside our house. The picture was clear and the diagnostic screen showed the signal as good. Switched out some of the lengths of cables. Again no problems.
Brought back the cable box and connected back to splitter. Glitchy audio and video and the signal strength was now fair. Bad splitter. Yup, the splitter went bad and was introducing all sorts of noise into the signal. So Adam went to the garage and found two splitters - one that was being used when we bought the house 6 years ago and a 'Pulser' brand splitter from Canadian Tire. Plugged them in and the signal was glitch free and the SNR was good. We could probably pick up a few extra dB in signal strength by replacing the cable from the first splitter (one run to the cable modem, the other for TV) to the second splitter and by purchasing a higher quality splitter. But so far the signal has been clean - no glitches, no problem connecting to the VOD server.