HD PQ Softer recently?

Discussion in 'DIRECTV Programming' started by charlie460, Jan 23, 2012.

  1. charlie460

    charlie460 Godfather

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    Anyone else notice that many HD channels are starting to look softer lately?
     
  2. sigma1914

    sigma1914 Well-Known Member

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    No.
     
  3. P Smith

    P Smith Mr. FixAnything

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    Provide ch numbers, we will check bitrates.
     
  4. charlie460

    charlie460 Godfather

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    NBC Sports (603), Sony (563), Universal (564), Smithsonian (565)

    The latter three being from the HD Extra pack, I've always noticed exceptional PQ from those channels but it seems a bit softer to my eyes recently. I may be crazy.

    Thanks for checking!
     
  5. P Smith

    P Smith Mr. FixAnything

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    I would go into ... could you this time give me sat and tp# of the channels from last gct's table while I'm do deploy a special Earth station.
     
  6. P Smith

    P Smith Mr. FixAnything

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    OK, it's 103W tp4,12: all those channels showing 9+ Mbps bitrates from 38.7 Mbps total mux. But it's changing all time.

    When you will see better PQ, let me know, we will compare bitrates.
     
  7. HoTat2

    HoTat2 Hall Of Fame

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    Well specifically, transponder 4 on 103cb (D10), and transponder 12 on 103ca (D12).

    Were those the ones you checked since there is a Tp. 12 for both 103ca and cb?

    NBC Sports HD ch. 603 --- DIRECTV 10 Tp. 4

    SONY HD ch. 563 --- DIRECTV 12 Tp. 12

    Universal HD ch. 564 --- DIRECTV 12 Tp.12

    Smithsonian CH. HD ch. 565 --- DIRECTV 10 Tp. 4
     
  8. DJ Matt

    DJ Matt Cool Member

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    I haven't noticed a drop off in quality for national HD channels, but sometimes my local channels (Chicago) seem to have more compression recently than what they have had in the past. Not sure if its just me or what. I also am getting a weird artifact on ABC. Whenever I watch or record something from ABC every now and then I will get this horizontal line artifact in the upper 1/3 of the screen. It lasts for about a little less than a second, but this just recently started happening in November and is a minor annoyance.
     
  9. P Smith

    P Smith Mr. FixAnything

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    Well, if I would have that Earth station down there (recently putting on sale for $12M :eek2: ) I would easy pick one sat: D10 or D12, for now both seen by any reasonable size dish (OTARD: 1M max) as one source of Ka waves.

    Now [21:33 PDT] Universal 564 is 6- Mbps.
     
  10. HoTat2

    HoTat2 Hall Of Fame

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    What I meant was that earlier you only mentioned transponders 4 and 12 at 103W, but for transponder 12 which one specifically did you measure?

    There are actually two CONUS beam transponder 12s at 103W. One from DIRECTV 10 on Ka B-band at 18.524 Ghz RHCP and another from DIRECTV 12 on Ka A-band at 19.930 Ghz LHCP (both frequencies according to FCC documentation).

    You mean your equipment can't see the difference between 18.524 and 19.930 Ghz?
     
  11. HoTat2

    HoTat2 Hall Of Fame

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    Also P. Smith, pardon my noob-sounding question here. :)

    But just to clarify, I know its been well established that the SR for DIRECTV's transport stream is ~30 mega-symbols per sec. So at two bits per symbol for a modulation type of QPSK for the CONUS beams, isn't that 60 megabits per sec. for the total bit rate?

    Therefore is your lower "38.7 mbps" figure mentioned above the bit rate minus overhead data such as FEC or some other?
     
  12. charlie460

    charlie460 Godfather

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    Yikes!
     
  13. charlie460

    charlie460 Godfather

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    Can you check the bitrate of NBC Sports Net (channel 603)? D10@103W (CB) Tpr 4
     
  14. P Smith

    P Smith Mr. FixAnything

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    Sorry, missed your call - been busy whole day ...
     
  15. P Smith

    P Smith Mr. FixAnything

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    Perhaps we should use TID## as uniquely addressed transponder in each network (what cover one or more sats [eg one cluster] as you know).
    The earth-station equipment is approved to pick all frequencies what all typical receivers do. And it do show real-time bitrate of each PID and whole mux.
    If you interesting to calculate the theoretical value of bitrate, you could pick some on-line calculators; yes FEC value is significantly affecting it.
    I recall the formula been posted here long time ago, when discussed advantage of 8PSK vs QPSK. BTW, some Ka tpns use 8PSK (check Sixto's threads).
     
  16. HoTat2

    HoTat2 Hall Of Fame

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    OK, I admit I'm still a bit fuzzy on this issue on how exactly you measure the bit-rates on these individual channels and will have to meditate on this one for awhile I guess. :)

    Will this rather simple one in the JPEG attachment do? Found it in a pretty good published series back in '09 geared for the layman titled "Satellite TVRO" on the "Broadcast Engineering" web-site.

    And if so can you confirm that the "Code Rate for the Reed-Soloman" (the "CRrs") FEC factor used by DIRECTV is the same as the one mentioned in the image at 188/204?

    Yes I know, but only on the Ka-band spotbeams I understand, since their beam's higher PFD compensates for the loss in noise and interference immunity by going to the higher level digital modulation.
     

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  17. P Smith

    P Smith Mr. FixAnything

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    Yes, they using compliant DVB-S/2 packets on Ka tpns.
     
  18. HoTat2

    HoTat2 Hall Of Fame

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    OK, thanks;

    Since you've mentioned before that DIRECTV is actually using a proprietary "DVB-2SD" format, I wasn't sure if the data packet/data packet + RS block error correction code ratio was the same or not. :)
     
  19. P Smith

    P Smith Mr. FixAnything

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    Lyngsat note it as DVB-S2D.
     
  20. JcT21

    JcT21 Legend

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    interesting that i noticed this thread.... i was telling my wife this morning that the HD looks a little different. i was thinking a tad "blurry" or a better term would be "softer" than it used to be. but yeah, i noticed it right away on TBS and CNN today. just so happen i got the new hd gui software last night. wonder if any of this is related.....:confused:
     

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