OK, the configuration and project is as follows: I have cable television from Comcast. The Comcast feed into the house has, over time, been sent to various rooms via different schemes of various gains and losses, but at the moment there is a 1:3 splitter feeding only three rooms. Amplification schemes are not part of the test configuration, but may be used in the future as more rooms are returned to the coax network.
The computer in use is the one with Cinnamon Mint 14 (Desktop 2 below). It is capable of converting and displaying 1280p H.264 .mkv video files while performing other tasks. Its capability in concert with 950Q demodulation remains to be seen, and is one purpose of this testing.
The feed to the 950Q at the computer is, for these tests, receiving -7 db (IIRC) of the Comcast feed from the pole. I don't know the signal level of the raw feed. The Comcast feed is encrypted, but is detected by w_scan via the 950Q as QAM 256. To view it decrypted with an "old time" analog television, which expects unencrypted NTSC at its antenna input, I have to use a converter, either one of the largish units Comcast provides (I have an analog output one in use on another TV) or one of the small boxes that Comcast made available (probably under duress) to compensate for making their cable feed purely digital and otherwise immediately obsoleting analog TVs. Somewhat more recently after that change to purely digital, Comcast also encrypted the cable feed on all channels.
If I want to view what is on the Comcast feed with my computer using the 950Q, but without a digital-to=digital converter box, I have to convert the encrypted QAM256 to NTSC via the available small converter box and view the result with the analog capability of the 950Q, because the small converter box is all I have available for testing. Historical attempts to obtain digital converters from Comcast have been sabotaged by their internal systems and after two tries, I gave up dealing with their pathetic organization other than to feed them money. Their feed is not my primary source of either information or entertainment.
Cable television may not be the the wave of the future, but I thought it would be interesting to see if I could add TV viewing at the computer without buying another TV. At this point, buying the TV would be more economically effective than doing these experiments and delving for the correct firmware, but buying a TV would require that I obtain a digital-to-digital converter box from Concast (sic), a task that might be achieved, but would also take a lot of time, potentially more time than working the hours needed to buy the TV.
So, my situation for these tests is that I have to take the encrypted feed and decrypt it, and the only means immediately available is to decrypt it via a Comcast converter that has an NTSC output on channel 3. The 950Q includes capability for an NTSC input signal. I now know that the encrypted feed is present and detectable by the 950Q. What I haven't done is successfully convert it and have the 950Q pick up the channel 3 NTSC analog signal. The small converter boxes provide no feedback other than what is showing on the TV, so I need to set up the test converter on another TV, which I haven't done, and then move it to the computer. This will be a future test due to my time constraints, but I'll keep you posted.
Thanks for your attention to what was intended to be a capability enhancement, but has now become an experiment.
Desktop 1: DFI Lanparty UT nF4 SLI-D/AMD Athlon 64 San Diego 2.2 GHz/G.SKILL 1GB x 2 DDR 3200/BFG GeForce 7800 GT/Ubuntu10.04
Desktop 2: Gigabyte 770T-USB3/AMD Phenom II X4 965 3.4 GHz/s. Talent 2GB x 2 DDR3 1333/EVGA GeForce 9800 GT/Mint 14 Cinn-lowlat