Frequently Asked Questions

What is clear QAM?

Clear QAM means digital cable channels sent without encryption. Any TV or tuner with a QAM tuner can receive them by connecting directly to the cable outlet and scanning. See Clear QAM.

Does my cable company still send clear QAM channels?

Possibly, but many large systems now encrypt everything. The quickest test is to connect a QAM-capable TV directly to the outlet, choose cable as the source and run a scan. Your provider can also tell you.

Why did my cable channels stop working on my TV without a box?

Most likely your operator began encrypting them. The FCC allows all-digital cable systems to encrypt even the basic tier. Once a channel is encrypted, you need the operator's box, adapter or app, or a CableCARD device where supported. See Cable Encryption and Clear QAM.

Can a QAM tuner decode encrypted channels?

No. A QAM tuner can demodulate any QAM channel, but it cannot decrypt one. Decryption requires the operator's conditional access system.

Is QAM the same as ATSC?

No. QAM is the modulation used on US cable. ATSC is the over-the-air broadcast standard: ATSC 1.0 uses 8VSB, and ATSC 3.0 uses OFDM. Many tuners support both QAM and ATSC 1.0. See QAM vs ATSC 1.0 and ATSC 3.0.

What is the difference between 64-QAM and 256-QAM?

A 256-QAM channel carries 8 bits per symbol and about 38.8 Mbit/s of usable data in 6 MHz. A 64-QAM channel carries 6 bits per symbol and about 27 Mbit/s. 256-QAM needs a cleaner signal. See What Is QAM?.

Why does a channel show up as something like 79.3?

On cable, a clear QAM channel is often listed by its physical cable channel and program number, because many systems do not send the channel names and numbers a set-top box uses. See Channel Scanning and Virtual Channels.

Is CableCARD still available?

It depends on your provider. Congress repealed the rule that pushed operators to use CableCARD in their own boxes, and the FCC later eliminated its CableCARD support rules. Some providers still supply cards; others are moving away from them. See CableCARD.

Will an ATSC 3.0 tuner get every NextGen TV channel?

Not always. Some ATSC 3.0 broadcasts use DRM encryption that only certain devices and apps can play. Where a station still offers an ATSC 1.0 version, that remains available on ordinary tuners.

Why is my picture pixelating?

Pixelation means the tuner is getting more errors than it can correct. Common causes are loose connectors, too many splitters, damaged cable, or a signal that is too weak or too strong. See Cable Signal Levels and Troubleshooting.

Do I need an amplifier?

Only if your signal power is actually low, usually because of many splits or long cable runs. An amplifier also boosts noise and can overload tuners. See Coax, Splitters and Amplifiers.

Can I watch local channels for free?

Often, yes, with an antenna. Standard ATSC 1.0 broadcasts are free and unencrypted. Check the FCC's reception maps to see what reaches your address. See Over-the-Air Broadcast TV.

Sources

Good to know. Cable lineups, encryption policies, equipment fees and device support are set by each provider and manufacturer and can change. Check with your provider and the sources listed before you buy equipment.
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