| Video Noise February 2004
Does Your Next Video Display Need to Have a QAM
Tuner?
Satellite customers who don’t intend to ever have
cable in their homes needn’t worry about QAM tuners at all. But if you’re a
cable subscriber who expects to remain so, a QAM tuner might be of interest.
When cable companies ran out of bandwidth for analog cable
channels, they turned to digital transmission to increase the number of available
channels. This allows many cable systems to carry hundreds -- possibly even more than a
thousand -- channels of programming. Digital cable allows for 30 to 100 pay-per-view movie
channels with scheduled start and end times. It also makes possible 10 to 50
movie-on-demand channels that allow you to start a movie any time you want, have access to
that movie for 24 hours rather than one viewing, and, when you do sit down to watch it,
have all the options you get with a VCR or DVR: stop, rewind, pause, etc. Digital cable
permits multiple versions of various "pay" channels, such as HBO, Showtime,
Cinemax, Starz, etc. Sports subscriptions of various types are also available on digital
cable systems, as are special events, and 30 or more channels of continuous music without
commercials.
The complex signals a cable company generates to carry all
that programming are far beyond the capabilities of the simple broadcast UHF and VHF
tuners that have been in TVs for decades. This is why cable companies give you set-top
boxes, which you need to receive all of their digital and analog channels.
QAM stands for "quadrature amplitude modulation,"
the format by which digital cable channels are encoded and transmitted via cable. Until
recently, there was no standard for how this was done; most cable systems were
incompatible with those of other companies. The FCC recently issued a ruling requiring all
cable providers to use the same QAM scheme; the tuners beginning to appear in home video
displays now use this scheme.
Theoretically, a QAM-equipped TV is all you need to receive
digital cable channels. Most people assume that, rather than having to pay the cable
company rental on the set-top box and remote, all they’ll have to do now is to
connect the cable to the video display and use the display’s remote control to view
digital cable channels.
But there’s a fly in the ointment. Cable companies
charge extra for digital cable service. Not a lot, usually -- in my area, it’s just
$3 per month. But you can’t receive the digital channels without the set-top box,
which sets you back another $7 a month. Add $0.60/month for the remote, and the cable
company is getting a little over $10 a month for each digital cable subscriber -- more if
the customer has more set-top boxes.
The capabilities of QAM tuners now appearing in some new
TVs are not completely clear. The owner’s manual of one model I examined contains no
information about using the built-in QAM tuner and what it can or can’t do for you.
If the TV’s QAM tuner can’t be addressed by the cable company, as the set-top
boxes can be, you may not be able to receive digital cable channels without a set-top box.
That could make the built-in QAM tuner useless.
There’s a chance that some cable companies may decide
not to encrypt local channels that are on their digital band. If that happens, you might
be able to get local HDTV broadcasts via your TV’s QAM tuner without having to have a
set-top box. This would spare you the considerable hassle of installing a largish antenna
to receive local HDTV broadcast channels, even if you don’t live very far from the
broadcast antenna. There may be some value to having an internal QAM tuner, but the
amount of value depends on your local cable company, their digital programming, and the
capabilities of the built-in QAM tuner.
One story that has made the rounds in recent months is of a
consumer who brought home a new TV with a QAM tuner. He was paying only for analog cable,
not for digital cable or any of the services on the digital band. When he flipped through
the channels, he found he could receive all of the digital cable channels on his new TV.
Not one to make any waves, the guy enjoyed digital cable for a while, until the channels
began disappearing one by one. Over the course of a few days, every digital cable channel
disappeared from his set, each one apparently now encrypted by the cable company.
Whether a QAM tuner will offer you any worthwhile
functionality will be up to you to research in advance. Before you buy a new TV, call your
cable company and ask them, "If I buy a new TV with a built-in QAM tuner, what
programming will I be able to receive on that TV without one of your digital cable set-top
boxes?" Ask this as well: "Will I be able to receive local broadcast channels in
HDTV using the built-in QAM tuner in my new TV without having to have one of your
boxes?" The second question is important -- they may have forgotten about the local
HDTV channels.
...Doug Blackburn
db@hometheatersound.com |
