what's qam?

Suzanne

DTVUSA Rookie
#1
Or maybe it's quam? Someone told me that cable companies are required to show 7 channels for completely free with this qam thing. I really didn't understand what the guy was saying. Can anyone turn it into English for me?
 

SWHouston

Moderator
Staff member
#2
Quadrature Amplitude Modulation (QAM)

Basically, QAM is two different signals (analog or digital) which are 90° out of phase (that’s where the Quadrature comes in), then are summed, which is what your Receiver presents.

Though I am not sure about the “requirement” of this, I do know that Cable Companies apply this technology. When using a Decoder/Box other than theirs, one can decode several channels of QAM to view, which could not be viewed with standard Analog or Digital tuners.

Have a good Day ! J
S.W.
 

MrPogi

Moderator, , Webmaster of Cache Free TV
Staff member
#3
In a nutshell - these are the channels that the cable company should not require you to have a set top box to view, IF your TV has a QAM tuner.
 

n2rj

Moderator
Staff member
#5
So it's sort of the poor person's emergency channels or something. How do you know if your TV has one of those tuner things?
Check the owner's manual, it should say if it can receive digital cable. Most digital TVs these days do come with a Clear QAM tuner though. A few of them come with CableCARD capability which allows you to view encrypted cable without a box using a small card that the cable company leases to you.
 

n2rj

Moderator
Staff member
#6
Quadrature Amplitude Modulation (QAM)

Basically, QAM is two different signals (analog or digital) which are 90° out of phase (that’s where the Quadrature comes in), then are summed, which is what your Receiver presents.

Though I am not sure about the “requirement” of this, I do know that Cable Companies apply this technology. When using a Decoder/Box other than theirs, one can decode several channels of QAM to view, which could not be viewed with standard Analog or Digital tuners.

Have a good Day ! J
S.W.
The clear QAM "requirement" I believe is an interpretation of the FCC rules which requires that must carry (local) signals have to be receivable by all subscribers with no material degradation. Since they can't guarantee that all subscribers will have a settop box or CableCARD, they simply leave the local channels in the clear.

There are a few cable companies that have gotten waivers such as Cablevision because they claim theft of service. However, they were required to give free equipment to subscribers for a certain period of time.
 

Orrymain

, Blogger: Orry's Orations
#8
Okay, put this into English for non-tech phobs like me. This is coming through a cable line. Aren't I paying for cable already? Call me dumb, but I don't see the purpose or maybe it's more like I don't understand it. To have a cable line, I'm already paying for at least basic service.
 
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