Do Your QAM Channels Play Hide & Seek?

BobHelms

Member
Original poster
Aug 28, 2007
13
0
Cary, NC
QAM Tuners are great, let them scan whats available and enjoy HD with no STB. So you write the numbers down or commit them to memory for your favorite HD broadcast stations and all is well. Then one night you pick up your remote, punch in one of your favorite channel numbers and IT"S NOT THERE ANYMORE! After lots of searching and rescanning you find it has moved to a different channel number. What the *@)% is going on? OK stuff happens, and I have no control over what channel numbers are assigned at the Cable Plant, I'll just have to live with it. Then the next day these favorite channels move back to where they were to begin with, what a pain! Thank you Time Warner Cary NC. Has anyone else ever experienced this new free feature?
 
The cable companies do not sell you "QAM Service" so to be mad when they change the qam channel is crazy. You are not missing out on anything you are paying for. There are numerous reasons why the channel gets moved, one of the big reasons is automated the channel is moved by what is commonly called a "cherry picker" what it does is move channels around to different qams as bandwidth is needed more on one vs the other.

The basic concept of a digital channel is they only send the data that changes so if the screen changes very little like say your watching someone do a speech and the camera stays on that person, very little new data is sent so it uses little to no bandwidth, you could broadcast I dunno 20 different "channels" on a single QAM if that was the only data being sent, but say a Sports game changes very fast and very sporadic, so you could have far less sports programming on the same qam, so the "cherry picker" comes in and moves the channels as bandwidth is needed. If NBC is showing a football game they may need to put it on a QAM with far less other channels vs say if say judge judy is on.

Not to mention as they add channels they move stuff around etc. So dont expect "QAM Service" from the cable companies anytime soon specially since they are leaning toward SDV (Switched Digital Video) Your qam tuner will not work with it anyway. If you can pick them up be happy if not well, your not paying for it anyway.
 
The cable companies do not sell you "QAM Service" so to be mad when they change the qam channel is crazy. You are not missing out on anything you are paying for. There are numerous reasons why the channel gets moved, one of the big reasons is automated the channel is moved by what is commonly called a "cherry picker" what it does is move channels around to different qams as bandwidth is needed more on one vs the other.

The basic concept of a digital channel is they only send the data that changes so if the screen changes very little like say your watching someone do a speech and the camera stays on that person, very little new data is sent so it uses little to no bandwidth, you could broadcast I dunno 20 different "channels" on a single QAM if that was the only data being sent, but say a Sports game changes very fast and very sporadic, so you could have far less sports programming on the same qam, so the "cherry picker" comes in and moves the channels as bandwidth is needed. If NBC is showing a football game they may need to put it on a QAM with far less other channels vs say if say judge judy is on.

Not to mention as they add channels they move stuff around etc. So dont expect "QAM Service" from the cable companies anytime soon specially since they are leaning toward SDV (Switched Digital Video) Your qam tuner will not work with it anyway. If you can pick them up be happy if not well, your not paying for it anyway.

Thanks for explaining why and how channels move around. I asked TW support about this issue, they could not answer my question. In fact they don't talk much at all about QAM tuners. Aren't all the cable company STB using QAM tuners? Theirs must have the smarts to keep up with the "cherry picker". I wonder what will happen to all those STB when SDV is implemented?
 
Well because the STBS are designed to read the channel from the channel map directly. So it doesnt matter what channel the qam is running on the STB can keep up with the mapping, to always show "Channel 3" on "channel 3" regardless of it being transmitted on channel 50 or channel 30.

Most all STBS's just need a software upgrade to handle SDV Because it receives the channel map directly from the hub/headends Once you get the new software that you hear being talked about on this forum your STB should be able to handle SDV without much issue.
 
My qam channels have been the same ove a year already. Lucky I guess they haven't swapped them around. I do notice that when I put it on a HD channels sometimes it doesn't come in. I have to go either up or down a channel and go back to the channel I wanted then it pops in.