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RE: need a cable box expert

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In Reply to: RE: need a cable box expert posted by Joe Murphy Jr on October 09, 2011 at 17:20:24

Some cable sytems have unscrambled clear channel TV channels (aka QAM) floating right down the raw cable before it gets to the box. Mine does, and there are a dozen or more channels I can pull off the raw cable before the box using the QAM tuner built into mine and most other digital TV sets. I can get a number of HD channels this way that come down the raw cable, the 4 broadcast networks, Discovery, WTBS, WGN. But all the channels that are on non-basic cable are scrambled. So I have elaborate A-B switching wiring that allow me to feed the raw cable directly to the QAM Tuner in the TV set if there is a QAM HD channel, but still use the non-HD cable box to unscramble it if the channel is scrambled.

I'm not certain what you are trying to do. It matters greatly what type of set you are trying to use the cable box as a tuner for. If the set you are trying to drive is a newer flat panel TV set that has a built-in QAM tuner you are better off trying a raw cable feed directly to the QAM tuner in the TV as I am doing. But you might be trying to use the cable box as a digital tuner for an older TV set that lacks an ASTC or QAM digital tuner. While the cable box is a QAM tuner if there are clear unscrambled channels on the raw feed, the QAM tuner in the flat panel fed directly from the raw cable will likely do better.

I suspect not all cable companies are like mine, which has some unscrambled raw feeds of both standard and HD signals besides the scambled signals. Some companies might scamble everything even local channels, in which case you are out of luck, because there is nothing on the cable feed that doesn't require descrambling from the cable box. I've also discovered that the government subsidized tuners are ATSC but not QAM, which means they will tune a non over-air channel from an antenna, but are worthless in pulling anything off a raw cable feed, even a local channel.

Follow Ups:

here's the deal - Joe Murphy Jr 20:51:45 10/10/11 (3)
The cable company does not scramble "free" digital channels (those which are broadcast OTA which, by the way, I believe would be a violation of FCC regulations), even 5 HD channels. I think the rule is that they can choose to not offer them, but they can't offer them as scrambled channels. If I'm misunderstanding something, someone please correct me!

I do not want to pay the cable company an extra fee -- which would be close to $15 a month -- for using two of their cable boxes (two of the displays I have are monitors, not televisions) to tune in the channels. I have two HD tuners that do NTSC/QAM/ATSC, but there is a component or components on the motherboards that are acting up (pick a channel, leave it there, no problem -- start changing channels, both tuners turn themselves off and can't be used for a few hours). They've worked fine for the last 2 1/2 years, but now they are practically toast because the motherboard is no longer made and the seller/manufacturer can't repair them -- probably a chip that has gone bad.

The tuner market for NTSC/QAM set top boxes is a scam. The prices are total bullshit and the products with a decent price are mostly crap. Some say they offer QAM tuning, but can't tune to QAM channels. Others tune to QAM channels, but not all of them or only the SD QAM channels, despite the fact that they are advertised as HD tuners. In order to get an NTSC/QAM tuner that really works, you have to spend about $200. What a crock of shit!

There are people selling cable boxes for around $70. The problem is that in order to use them, the cable company wants to charge me to use something that isn't theirs, as a signal needs to be sent to the cable box in order for them to allow the box to work (if a box is addressable, it has to talk to the cable company in order to work). If I can disconnect or bypass that part of a cable box that I buy, it will act like a normal tuner for the signals that the cable company sends down the pipe unscrambled.
- RE: here's the deal - blue_z 14:19:38 10/13/11 (0)
  > Others tune to QAM channels, but not all of them or only the SD QAM channels
  
  Seems like that digital TV tuner only supported 64QAM demodulation, and not the 256QAM that the HD cable channels typically use. Most digital TV tuners don't bother to specify which type(s) of QAM demodulation is/are implemented.
- RE: here's the deal - DavidLD 04:48:53 10/13/11 (1)
  So far at least, I have had good luck using this unit, a Toshiba DVR670 DVR as a QAM tuner on a HD projection TV that lacks a digital tuner. The unit wasn't trouble free and the sound on the VHS section didn't work on the first unit. Fortunately that problem cropped up in the first 90 days and It was replaced under warranty.
  
  The tuner is able to send signals to the TV in 480p, 720p 1080i, and 1080p. The rear projection TV I own only works thru 1080i, and sending it a 1080p not HDMI thru the DVI connector on the TV correctly produces a black screen.
  
  The unit has an HDMI out on the back. I have a cord with HDMI on one end and DVI on the other, and then send the audio to RCA jacks that are next to the DVI connector.
  
  Since I can easily flip between resolutions on the DVR, I've had an interesting education as to what exactly the differences are between, say, 720p and 1080i with respect to picture quality.
  
  The discussion on these units centers on whether the unit passes thru a true 720p or 1080 signal or whether it first downscales it to 480p, as that is whjat it needs to record on the DVD recorder. The HD signal on the projection TV isn't as sharp as a state-of-the-art HD flat panel, but that may be more a limitation of the projection technology not the tuner. I actually like the picture on the rear projection set very much, in that it seems very theater-like, with just the right degree of sharpness. The edgy look of some of the new HD sets to me seems almost too much. The TV from 2005 is working fine, always has, and I have a spot for it such that the depth is no big deal, so I hang on to it.
  
  BUT, if I were in your shoes, I would be more inclined to put $200 in one of the Toshiba DVRs with tuner than to sink $70 into some dumb cable box or even some no-came tuner that claims to be QAM
  
  Also, the DR570 model
  http://www.amazon.com/Toshiba-DR570-DVD-Recorder-Player/dp/B001TOD3KK/ref=sr_1_3?s=electronics&ie=UTF8&qid=1318505902&sr=1-3
  has the tuner but not the VHS to DVD capability, and I see that is only $157. Should be the same tuner setup.
  
  We are getting down nearer the prices you are seeing on the used cable boxes.
  
  Panasonic I think also makes a DVR with a QAM tuner, but I think that one is $300..Ahhh I found it..that one runs $249
  
  http://www.amazon.com/Panasonic-DMR-EZ48VP-K-1080p-Upconverting-Recorder/dp/B0014F9U6U/ref=sr_1_2?s=electronics&ie=UTF8&qid=1318506160&sr=1-2
  
  So far as I can determine these are the only units with QAM tuners in built by name brand manufacturers.
  
  D
  - Toshiba 670 DVR (Open in New Window)
  - thanks for the info - Joe Murphy Jr 07:21:14 10/13/11 (0)
    I have a few other options to consider, but so far none of them really make me want to budge on the issue. In the end, I may have to just give in and deal with it.
    
    Appreciate you looking up those options for me.

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