The problem here is trying to figure out what you are being sent. I have Cablevision and OTA, and the DHG and the TiVo are both cablecard. My units get, and have always gotten TVGOS from the OTA feed, CBS 2.1, transmitted in NYC on UHF 38. Now, in terms of what comes in, is a bit of a mystery.
I began with the one TV box we have from the cableco, to get a definite list of "what we get" and "what we don't get". After elimination of home shopping, sports, religion and porn channels, I had a pretty good idea of what the cable co sends down with a box that I'd care about. (It became a three page chart).
The next step, for giggles, was to take a Sony TV with a QAM tuner, and do a scan of cable-it locked up at 530 or so channels, and stopped scanning.
There is no CableCard in this unit, and what I found was that the only HD channels were the "must carry", which mapped properly to 2.1, 4.1, 7.1, etc....there was also a tier of all local broadcast channels, again QAM, in SD feed, probably for the SD boxes still out there in use. They were all sent as part of one QAM channel. All the basic cable analog stations (Discovery, Comedy, etc) were gone as clear QAM, but part of the "digital" change on our system was clearly to monetize all those kitchen and garage TV sets. (My free for a year cable box goes back month 11 and I'm back to OTA on those units)
So, as hooked up, both the DHG and the TiVo wil get channel 2, an SD feed. If I hit 2.1, I get OTA channel 2 in HD, and my system uses 702 as the HD feed of 2. I don't know the actual channel the clear QAM sends "2.1" down on. There are also a few other channels the cableco sends SD in the 100 series but HD in the 700 series. I had to remove all the duplicates, but keep the other secondary channels (H2, Military, a few PBS outlets) that are SD only.
The Tivo is handy as it will alert me when the channel lineup changes, so I can go to the HDD and manually fix whatever moved. BTW, Tivo isn't bug proof either....you can lose Dolby sound, and if you change resolutions frequently, it confuses the HDMI/HDCP DRM nonsense.
The tuners are an interesting comparison. With equal signal strength, the best tuner is the built in Panasonic TV, followed by the TiVo, and at a distance, the HDD Tuner. I don't have multipath issues, but have one station off-axis from the others, and the HDD gets "flying bricks" compared to the Panasonic or Tivo, who will only occasionally pixelate but generate a useable signal.
Edited by speedlaw - 7/7/12 at 10:11am