I currently have Comcast limited basic service. I connect directly to the cable and get analog channels 2-35, 71-77, and 81-82. The other channels are filtered out. Can I expect to receive clear QAM channels? I have tried using my Philips DVR (DVDR3576H), but without success. That is the only device I currently have with a QAM tuner. Perhaps the QAM channels get filtered out also?

Do you have the 3576 1st on the coax, as shown in Sketch #1 here? (http://www.avsforum.com/avs-vb/showpost.php?p=12298409&postcount=10)

And did you do an Auto Channel Preset (Analog/Digital), as described here? (http://www.avsforum.com/avs-vb/showpost.php?p=12298432&postcount=12)

If yes to both, Comcast has apparently blocked all clear-QAM channels in their "limited" basic service?

Yes on both. I have no clue about cable RF frequency usage, but is it possible or probable that the RF frequencies of all the clear QAM channels lie in the range that is filtered (i.e corresponding to analog channels 36-70)?

I'm not sure whether my Philips DVR has a problem or whether I don't have any clear QAM signals on my cable. I guess it will have to wait until I get a HDTV with QAM tuner before I know for sure.

Analog and digital channels are on different tuners in the Philips... it has a "hybrid" tuner that requires a manual switching between analog and digital... not like a HDTV that has both integrated so channel up/dn tunes them all in sequence.

Have you pressed the DTV/TV button to switch to the digital tuner (2nd row, 2nd button down on remote)?

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Have you pressed the DTV/TV button to switch to the digital tuner (2nd row, 2nd button down on remote)?

Yes, with the analog tuner I get the channels that I listed above, and with the digital tuner I just get a blue screen with "Now Tuning" displayed forever.

It is possible that your local Comcast system is still using inline filters outside of your home. Most systems that have been updated no longer have these filters.

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Most systems that have been updated no longer have these filters.

For these updated systems, what method is used to block the analog channels that are not included in limited basic? (Limited basic only includes the broadcast channels and a few others. It is the absolute minimum service available)

Are you using cable/broadband internet service???

Are you using cable/broadband internet service???

No, just limited basic cable TV.

You won't get any clear QAM then...There is a filter inline that blocks those frequencies...One option is to call and get digital cable service...Or you can get internet from them...drop who you have now...and then you'll get the clear QAM channels...Sort of an unspoken 'bonus' when receiving HSI from the cable co...

You won't get any clear QAM then...There is a filter inline that blocks those frequencies...One option is to call and get digital cable service...Or you can get internet from them...drop who you have now...and then you'll get the clear QAM channels...Sort of an unspoken 'bonus' when receiving HSI from the cable co...

Thanks for your reply. I think your assessment of my situation is correct. I don't intend to go beyond the limited basic service with Comcast that I currently have. The clear QAM would have been an added bonus if I could get it with my current installation. Now I know that I can't and why. I am OK with that.

gotok,

FWIW... both of my son's have "limited basic" (with Comcast). One has HSI, the other does not. They both can get QAM "locals" enencrypted. Have you contacted your cable provider and asked about receiving these channels with your existing subscription package? All they may need to do is make some filtering adjustments at the pole/ped to accomodate your request.

Local broadcast channels in HD is considered part of LIMITED BASIC!
A QAM tuner SHOULD be able to receive these channels.

Here is where I found the QAM channels for Comcast in Seattle, for their limited package -- approx $14 a month:

http://www.mythtv.org/wiki/index.php/Working_QAM_cable_layout

It is possible that your local Comcast system is still using inline filters outside of your home. Most systems that have been updated no longer have these filters.

How is that done? Without installing a trap outside the house, how do you filter out the upper level analog cable channels?

I have Comcast and recently cancelled all my digital cable service and kept the limited basic since it only costs $12.90 per month and I would have been charge a fee of $10 to have internet service without any television service anyway.

Before they installed the trap I received an incredible amount of channels on my QAM tuner. TBS, TNT, Comedy, Disc, TLC, USA, FX, Spike, and on and on. After they installed the trap I lost many of those because they were on digital channels 40.1 thru about 60.11. I still have FX, ESPN, ESPN2, etc. but I lost a lot of good channels. I still don't understnad why I lost QAM channels because of their channel number, I thought the whole point to digital QAM was that they were on a different frequency (in a range close to the cable modems frequency) and that a trap wouldn't filter them out.

I called about having the trap removed to get just the basic analog channels and they said ot would cost $57 per month!

I have a question that coincides with this topic. If I have Comcast and currently have HD service through them on one TV (and basic cable on the others), would I be able to get the HD channels on another TV that has a built in QAM tuner without having to rent another HD box from Comcast? Thanks!

It depends on what they decide to send "in the clear," i.e., without encryption that requires a box. It tends to vary even within Comcast's own system.

Usually your local affiliates (ABC, NBC, etc.) are in the clear, and things like PBS and maybe Discovery HD. Best way to tell is to have the QAM tuner scan and see what it picks up. Anything you don't get will usually need the box or a cable card.