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Sixto Report-D12 Status: Pre-Launch

Discussion in 'DIRECTV General Discussion' started by Sixto, Jul 27, 2008.

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  1. Feb 3, 2009 #561 of 1236
    Alan Gordon

    Alan Gordon Chancellor

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    There are no spot-beams coming from 110.

    ~Alan
     
  2. Feb 3, 2009 #562 of 1236
    Sixto

    Sixto Well-Known Member

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    110 only has 3 transponders, no spotbeams, and 9 channels.
     
  3. Feb 4, 2009 #563 of 1236
    inkahauts

    inkahauts Well-Known Member

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    All right.. I love this thread.. and I love to speculate.. And I am going to, even though I have no idea if anything I'm saying is actually possible... So....


    I think the first thing we need to answer.. There are 49 spotbeams on EACH of the new sats... D10, D11, and D12. My question is, whats the fewest number of transponder frequencies they can use and still have all 49 filled to capacity on EACH satellite?

    Frankly, a lot probably depends on the actual configuration and pointing of the spotbeams, but I wouldn't be surprised if they could get all of the spotbeams running on less than 5 transponders.. Why...

    I believe that D9s is the only sat with spotbeams at 101.. And there are 6 on that sat.. And there are 42 spotbeams on that satelite. Assuming that they may have made these spots sizing similar, yet a bit more defined... There is no reason for me to believe that they can't fit them all in in a very small number of trasponders...

    Also of note...

    They know that in theory they can duplicate anythign they do on D10 on D11, (or D12 and D11, etc) and therefore, you have to start thinking about the fact that you could have twice the frequency space for any one sat spotbeam transponder because you can have the exact same frequency coming from 2 locations and heading into the same home.... which is especiall important in areas that have lots of channels, or multiple DMAs right next to each other that are covered by say only one transponder on any one given sat.

    As for why the spaceways are so important.. They can pick and choose where they fire, and what they fire, so in thoery, they can be used to fill in the gaps, and maybe even supply just enough extra bandwidth for one channel in any one given dma.. leaveing the rest of there bandwidth to "advanced features in the future" as people have noted...

    And between D10, D11, and the 2 spaceways, they are supposed to be able to transmit 1500 HD LIL channels... Thats one heck of a lot of channels.. and If they can fully utilize all 49 transponders on all three D's at the same time, and each can do 500.. and hopefully only use say 4 or 5 transponders on the loaner sat, and say 6 or 8 from the location that will have two of them parked.. then we are looking at 2000 HD LIL channels... and hopefully still full capability on 42 conus transponders...

    One other thing of note.... Why is it that each transponder is 7x the frequency of a uhf or vhf station, (according to Tom's post... http://www.dbstalk.com/showthread.php?t=82295) yet they only have 36mhz, and can only show about 5 channels a transponder? And if they each actually have 40mhz of spectrum.. any reason they can't combine say, some sd channels in with hd to fill that last 4mhz or so? And if they did that, then maybe they could free up some transponders on say, 101 and then shoot some HD off those sats?

    I swear, its the most complex rubiks cube ever...
     
  4. Feb 4, 2009 #564 of 1236
    HoTat2

    HoTat2 Hall Of Fame

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    Then are any spots from the older DIRECTV-4S at 101 no longer used?

    Not sure I follow your reasoning/math here, can you rephrase this? :confused:

    If the reason for the Ka's transponder frequency spacing plan is the same as with C-band for instance, then the additional 4 Mhz (or +/- 2 MHz to either side of a Tp.) are set aside for guard bands to prevent any adjacent transponder channel interference due to uplink transmitter frequency error.

    Thus this additional spectrum is not recoverable I'm afraid...

    Oh, and Go Lakers!!! as well. Though with the loss of Andrew Bynum (again!) I'm afraid the "Go" has just lost some critical steam...
     
  5. Feb 4, 2009 #565 of 1236
    harsh

    harsh Beware the Attack Basset

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    That would be a unique situation indeed if the FCC filings said anything that didn't require an expert to decode.

    Fortunately, there are a few here that seem to be pretty adept at FCC speak.
     
  6. Feb 4, 2009 #566 of 1236
    Tom Robertson

    Tom Robertson Lifetime Achiever DBSTalk Club

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    Very good analysis :)
    HoTat2 is absolutely correct, the 4mhz are guard bands separating each transponder from interference. That is one reason DIRECTV carved up the bandwidth into fewer chunks that are larger--also means fewer guard bands.

    Secondly, when I wrote the analysis on bandwidth, I did not know about nor account for the Forward Error Correction (FEC) bits needed to overcome the errors in transmitting from space. That eats quite a bit of the overall bandwidth of data. DIRECTV has tried various schemes of modulation and FEC to maximize the data rates. So that explains some/most of the difference between the analysis I did and the reality of what we got. (I'm allowing that I might have missed something else explaining more of the difference.)

    And yes, very complex Rubiks cube. And I too am still learning from the other great people here. Thanks!

    Cheers,
    Tom
     
  7. Feb 4, 2009 #567 of 1236
    evan_s

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    Hmm it is interesting how few locals the Spaceways seem to be hosting currently. That would either indicate that DirecTV still has a lot of locals space to be fired back up or they are planning to do something with them. It does make sense to use as much of the local capacity on d10/d11 as possible since it is more efficient but less flexible. It seems like they are pretty close to moving everything off spaceway 2 and should be able to move all the locals it has off to some combination of spaceway 1, d10 and d11 with out too much difficulty. That would be prefect for moving spaceway 2 to be colocated with spaceway 1 and sticking D12 in the newly empty ka hi slot.

    If that was the plan the only thing that seems off is why only say 200 national channels? The only guess I can come up with is with 14tps from d10 and d11 and 5 channels per TP they each only end up hosting 70 channels. I know there has been some speculation where they would be able to get the 10 more channels they would seem to be missing. Maybe they are planning on 210 from the three sats and just rounding down. 200 would seem like a more accurate statement if you are no longer trying to claim the east and west coast Distants as HD channels since most people can not legally get them.
     
  8. Feb 4, 2009 #568 of 1236
    Sixto

    Sixto Well-Known Member

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    Just looked through the gct 2/1 transponder data again ... http://www.dbstalk.com/showthread.php?t=151550

    If I was to guess just based on this transponder data, I'd say D12 is going to 99° Ka Hi.

    Now, based on us thinking that they're not going to adjust the D12 payload then maybe not but ...

    D10 and D11 are filling up every LiL transponder from 15-24. Every transponder is in use. Only just a few with a small number of channels.

    And Spaceway-2 is reduced as mentioned yesterday.

    Geez, why would you load up D10 and D11 on every LiL transponder if just several months later you're going to re-use the frequencies for D12.

    And why empty SW2 unless you have some change coming for Ka Hi.

    And why touch SW2 at all unless D12 was going to somehow effect Ka Hi.

    Or maybe SW2 will be re-tasked for something else?

    All this based on today's data ... all subject to change :)

    Code:
               [U]SW1[/U]     [U]SW2[/U]
    TP1         24       0
    TP2         21       0 
    TP3         18      25
    TP4         17       0
    TP5         12      20
    TP6         18      11
    
               [U]D10[/U]     [U]D11[/U]
    TP15        70      48
    TP16        28      45
    TP17         2      44
    TP18        39      28
    TP19        12       6
    TP20        39      35
    TP21        55      41
    TP22         9      22
    TP23        36      29
    TP24        21      17
     
  9. Feb 5, 2009 #569 of 1236
    hdtvfan0001

    hdtvfan0001 Well-Known Member

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    I'm betting my lunch money that D12 goes into the 99 slot (but then of course....I rarely eat lunch :D)...
     
  10. Feb 5, 2009 #570 of 1236
    Sixto

    Sixto Well-Known Member

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    gonna bet dinner on Ka Lo or Ka Hi? :)
     
  11. Feb 5, 2009 #571 of 1236
    hdtvfan0001

    hdtvfan0001 Well-Known Member

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    Now wait a minute....now we're talkin real money...:lol:

    KA Hi.. ;)
     
  12. Feb 5, 2009 #572 of 1236
    Sixto

    Sixto Well-Known Member

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    BTW, as I analyzed it deeper late last night, it did appear that the transponder data (in the other thread) was not totally accurate in mid-2008. It was identifying D10/D11 LiL as SW1/SW2 LiL for transponders 15-24.. Looks like it was corrected in the data after November.

    So SW2 was quite possibly not 200+. But SW2 still did go from 90+ count to 50's since Q4.
     
  13. Feb 5, 2009 #573 of 1236
    hdtvfan0001

    hdtvfan0001 Well-Known Member

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    Wouldn't the SW2 reduction come from the offload of alot of HD LILs to the other sats...?
     
  14. Feb 5, 2009 #574 of 1236
    Sixto

    Sixto Well-Known Member

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    yep, but the question is why move LiL off SW2? why take 3 of the 6 transponders to zero? unless you were preparing for some change ...

    could be many reasons including that they may need to deal with the D10 spotbeam issue and are first loading up D10/D11 before putting the difficult spots on SW1 or SW2. but they could have done that long ago after D10 launched in 2007.

    all while D10 & D11 LiL continue to grow and use every available transponder (15-24).

    while all of this may lead to the D12 Ka Hi assumption ... it is a leap of faith because then D12 would need to be re-configured, which we originally thought would not happen. but there has been much time to make a change, that SW1/SW2 space is underutilized, even more underutilized now.
     
  15. Feb 5, 2009 #575 of 1236
    LameLefty

    LameLefty I used to be a rocket scientist

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    Here's my take on it as a former spacecraft engineer . . .

    D10/11/12 were all ordered as triplets, to be configured more or less identically. However, the satellites were not built concurrently, but sequentially. D11 was almost certainly built out and completed following analysis of the spotbeam issue with D10 and modified accordingly.

    Remember, up to this time, D12 was still ostensibly to be used as a ground spare for D10/11, while there were other FCC applications and plans pending for future BSS use, etc.

    At some point, the applications for what was to be D13 were withdrawn and obviously priorities and plans shifted inside Directv for their satellite fleet. That means D12 no longer sits in a climate-controlled clean-room just in case and instead gets repurposed. And that's where we are today.

    So what does it take to repurpose a satellite planned for Ka-Lo to actually operate at Ka-Hi. Not much. New transmitter components. Feedhorns and antenna elements optimized for one particular frequency band instead of another, mostly. As Sixto pointed out, there's been ample time to make the configuration changes and tell the suppliers to substitute the new-spec components for the old.

    Assuming D12 DOES get flown in a Ka-Hi configuration, realize this: design changes like this happen all the time in industry and it probably didn't cost Boeing or Directv hardly anything extra to change the configuration this far in advance. The suppliers were on the hook to provide the equivalent Ka-Lo optimized components anyway, and there is no particular reason why Ka-Hi optimized widgets should cost any more, really. They should mass about the same, use about the same power, require about the same volume, etc.

    Of course, we could all be wrong about this, so who knows? :p
     
  16. Feb 5, 2009 #576 of 1236
    smiddy

    smiddy Tain't ogre til its ogre

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    You know, I half read this post and considered that you likely spend less than most on lunch, so that isn't that big a deal, and you ended it with you rarely eat lunch so...I suppose, it really is no big deal or you are not really a betting man. ;)
     
  17. Feb 5, 2009 #577 of 1236
    hdtvfan0001

    hdtvfan0001 Well-Known Member

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    Two days in Vegas at the CES seemed to prove that - spent $10 on the slots...

    In any case...LameLefty's assessment also makes a whole lot of sense.
     
  18. Feb 5, 2009 #578 of 1236
    smiddy

    smiddy Tain't ogre til its ogre

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    Yep, LameLefty is one smart guy. The combination of folks here too, make this thread a worthy must read on every login. :)
     
  19. Feb 10, 2009 #579 of 1236
    dwrats_56

    dwrats_56 Godfather

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  20. Feb 10, 2009 #580 of 1236
    LameLefty

    LameLefty I used to be a rocket scientist

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    Nope, sorry. That's for Directv's BSS application (a putative "D13"/future satellite to be named later).

    This is interesting though - it's setting aside a previous ruling that found the BSS application deficient. And doing it nunc pro tunc means that this new order has the legal effect of "erasing" the previous rejection, meaning Directv does not "lose its place in line" for BSS slots. :)
     
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