New HDTV sets with built-in QAM tuners are very popular. It is important for all consumers to understand how these new HDTVs work. The store that sells you your new HDTV should be the primary source of information and training on the features and operation of it. We try to help, but there are so many different manufacturers and models that we can't be experts in all of them. That is the job of the store personnel or the person who installs it.
The single most important thing you can do with your new HDTV is to read the Owner's Manual. PLEASE, take the time to learn how to use all of the features of this new entertainment source. It will greatly improve your enjoyment.
Many people do not take the time to understand their new HDTV set's capabilities and as a result, think they are watching HD, but are not. A recent US News & World Report article noted that 44% of HDTV owners are not watching HD programming.
What is QAM?
QAM stands for Quadrature Amplitude Modulation. It is similar to AM (Amplitude Modulation) or FM (Frequency Modulation). The terms don't really matter. Just keep in mind that it is just another type of tuner. Cable systems use QAM to transmit digital signals. These can be Standard Definition or High Definition. They can be encrypted (scrambled) or unencrypted (clear). A QAM tuner is able to receive unencrypted signals. A converter or CableCard is required to receive encrypted signals.
How do I know if I have a QAM tuner?
The Owner's Manual should include information about a QAM tuner. If there is no information in the Owner's Manual, the TV probably does not have a QAM tuner. A good place to start is the Specifications Section. Look for the QAM capabilities in the area with the Antenna or Tuners. Another way to check for a QAM tuner is to examine the remote control. A dot (.) or a dash (-) button on the remote is normally used during the tuning process. If the remote has a dot or dash button, the TV probably does have a QAM tuner.
How do I use my QAM tuner?
This will vary depending on the TV set. Typically, the QAM tuner is always active. The user just needs to enter the QAM channel on the remote control. QAM channels are made from two numbers (a "major" and a "minor" separated by a dot or dash). For example, USA Network is 52.1 or 52-1.
Which QAM channels are available?
Every Extended Basic Cable Channel is available for viewing with a QAM tuner. You can print a QAM lineup here.
How do I find all the QAM channels?
This also varies depending on the TV set. Most QAM tuner TV sets have a scanning function (typically called Auto Program, Channel Scan or some similar combination). Find the scan function in the on-screen menu and start it. You probably will see a progress bar that shows the number of channels found. A scan can take as long as 45 minutes depending on the TV set so be patient. When finished, the TV will have found all of the available QAM channels. The TV set will remember these channels for your later use. However, some sets do not have a scan function. For these TV sets, the user must manually enter each QAM channel.
What is the QAM lineup?
Everyone is familiar with the original VHS or Cable TV analog lineup. It is pretty simple. It starts with 2 and progresses one number at a time. Each channel in the analog lineup actually represents a frequency range that is 6MHz wide. For example, Channel 2 extends from 54 to 60MHz, Channel 3 extends from 60MHz to 66MHz, and so forth. The QAM lineup is built upon this foundation.
Digital transmission is much more efficient than analog transmission. We can transmit more than a dozen Standard Definition networks or 2 High Definition networks in the same space as a single analog network. They can't all be the same channel number, so a new number sequence must be used. It is called the "major.minor" system.
Let's use Channel 24 as an example. The QAM lineup starts with this VHS channel designation. This is the "24" in the QAM lineup. This is called the "major" number. The digits after the decimal point are called the "minor" number. A QAM tuner user should be able to tune to a channel by directly entering the major, then a decimal point (or dash) and then the minor (24.1 for KET 1). We call this process "decimal tuning".
We cannot change the major number, but we can set the minor. We set the minor number to match the channel number that appears on all types of converters. So, on Channel 24, we transmit the following Standard Definition networks:
24.1 - KET 1
24.2 - KET 1 HD
24.3 - KET KY
Why don't all QAM tuners work the same?
Unfortunately, different manufacturers have built varying levels of sophistication into their QAM tuner TV sets. We cannot control this.
- Some sets do not recognize the minor numbers we set. Instead, they simply assign their own minor number. In these cases, our QAM 79 becomes 24.1, 24.2, 24.3 and so forth.
- Other sets will recognize the minor and display it.
- Some QAM tuners will display a completely random set of numbers such as 68-56, with neither 68 nor 56 corresponding to any actual channel.
- Still, other sets allow the owner to rearrange the order in which the networks appear, apply labels (like channel names) and set lists of favorites to the QAM channels received.
We cannot change the capability of QAM tuner TV sets. Most consumers don't know to ask about these capabilities and many sales people don't even know about these differences.
Why don't converters or CableCards require decimal tuning?
Converters and CableCards use a "channel map." Entering "26" on the remote control tells the converter to tune to 79.26. We can't send a channel map to a QAM tuner TV set unless it is equipped with a CableCard.