Sounds like he was having some difficulties with the cabling going from the uBR (the uBR itself is just a router with CMTS cards in it, not much there to take all the bits out of
)
The HFC network is far more complicated, and if there are issues with the upconverters (the things that take the signals from the uBR and ramp the frequency up for injection onto the DTV streams) or the various splitters, multiplexers, media converters and amplifiers from there it'd do your SNR rather a lot of harm.