Assuming you're just paying for broadband Internet, they probably placed a filter on your line. Assuming you subscribe to both basic cable and broadband Internet, they probably accidentally placed a filter on your line.
Cable channels are nothing more than 6Mhz chunks of radio frequency (RF) being sent down the physical cable. An analog channels occupies the entire 6Mhz frequency, and traditional analog channels are typically in the range of 2-99. Channels 100 and above are usually digital. Using QAM256 encoding, there is a little more 38Mb of usable bandwidth in one 6Mhz frequency, in which most cable companies stuff 8 or more standard digital (SD) channels or 2 or 3 high definition (HD) channels using time division multiplexers.
For example, in my area:
- Analog channel 2 will suck up an entire 6Mhz RF
- HDNet, HDNet Movies, and local Fox HD will share one 6Mhz RF (78)
- Fox: physical channel 78.1 --> remapped to channel 705
- HDNet: physical channel 78.2 --> remapped to channel 770
- HDNet Movies: physical channel 78.3 --> remapped to channel 771
As you can see, supporting these analog channels is limiting their deployment of HD...not to mention the need for more and faster broadband Internet access.
I live near the end of the end of our subdivision. I haven't had cable TV for years, but I do have cable broadband since they are the only providers in the area (1/2 mile too far for DSL). It's been the same ole' story for almost six years:
1. Service is unfiltered since the filters seem to cause problems with our Internet service since we're at one of the further points (relays, connections, etc.) from our cable headend. We get all the crappy cable channels 2-99 that we don't need, nor do we watch since we have Dish Network, Star Choice (Canadian Satellite), and two OTA antennas.
2. Semi-annually they audit and adjust the taps (the locked boxes on the easement) and occasionally someone will fail to read the notes on my account and place a filter on the line. My Internet service may die that day, experience performance issues, or work fine until it fails a month or two down the road. Invariably we can always trace the source of failure back to someone placing a filter on the line, placing the wrong type of filter on the line, etc.
3. In most cases, the filter will block the RF being for analog cable only, and it will not impact the RF used for broadband Internet (both downlink and uplink) nor potentially any of the digital channels since those are already encrypted...with the exception of local broadcast HD channels, which are typically passed through without encryption. In this case, just plug the cable into your HDTV (assuming you have a built in ATSC tuner) and it should work.
4. Anyway, the cable techs will always wind up removing the filter from my line since it's too
Do you have a digital cable ready HDTV? If so, just plug in the cable and if you're able to receive your HD locals then you'll be 100% sure someone placed a filter on the line.
