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Expected coverage of new spot-beam satellites?

Discussion in 'DIRECTV General Discussion' started by Greg Bimson, Jul 25, 2003.

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  1. Greg Bimson

    Greg Bimson Hall Of Fame

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    I have created two maps for viewing pleasure. They simply identify the markets that are currently on spot beams at the 101 satellite, and the markets that will be on the spot beam satellite at 119 later in the year. Notice how they look somewhat similar:
     

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  2. Greg Bimson

    Greg Bimson Hall Of Fame

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    It is my belief, now looking at DirecTV's future plans, that DirecTV 7-S will be a mirror image of DirecTV 4-S. It should function as a backup to DirecTV 4-S, and therefore, it looks as if it will function exactly like DirecTV 7-S.

    It is specifically why some of the markets, such as Wichita, Toledo, and Springfield, MO, have been passed up at this juncture. I figure it may be possible that DirecTV will add more markets if they can figure out how to use a multi-satellite system and place locals at both 101 and 119 for a single market.
     
  3. AntAltMike

    AntAltMike Guest

    I believe that you have just violated the copyright of the US Geological Survey. Wet noodle lashes for you!

    You have posted observations in previous threads that tended to support the notion that there is something about DirecTV's guide software that limits its channel mapping flexibility. Back when DirecTV used to generate channel guides that placed local channels somewhere in the 900s, you had observed that, in some markets that had relatively small local channel line-ups, different channel numbers would be assigned in different markets for channels believed to be carried in the same transponder.

    For expositions sake only, since I don't remember the actual numbers that DirecTV used to use, lets say that DirecTV was assigning the numbers 940-953 to any local TV programming distributed by spot beam #4. So if one small market had eight local channels carried on that spot, they might have been mapped to 940-947, and if another market served by the same transponder had six channels carried on the same transponder, then they might appear in the guide on channels 948 to 953.

    Yet while it was obvious, when looking at TimF's (if I remember his screen name correctly) spot beam channel map chart, that DirecTV was using the same block of channel numbers for any channels carried by one spotbeam downlink frequency, and while it also appeared that they assigned different numbers for each channel uplinked together even if they didn't ever appear in the same subscriber's guide, I have never seen any software expert speculate as to why so mapping the guide channel assignments might have been necessary.

    DirecTV now maps all the local channels to their actual local broadcast numbers, at least on all of the hundreds of receivers that I have installed over the past year. I admittedly don't know if the guide in, say, an RCA DRD100 or a 303 still puts them in the 900s, but even if its software mapping ability is so limited, I don't believe such a limitation, by itself, would provide a unique obstacle to DirecTV using spot beams from both satellites to service one market, because those receivers don't have DirecTV "Plus" capability. So until someone gives me a reason to believe otherwise, I will assume that any DirecTV Plus receiver with 22Kz tone switching capability will be able to develop a guide that neatly integrates local channel retransmissions from different transponders, even if they are transmitted by different satellites.
     
  4. ChrisPC

    ChrisPC Godfather

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    The old non-Plus receivers do still map the locals in the 900s, and the 300s, 400s, 500s, 600s, 800s, etc.
     
  5. Greg Bimson

    Greg Bimson Hall Of Fame

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    Nice shot.
    As ChrisPC points out, those of us with receivers prior to the DirecTV-Plus standard are still receiving their locals in the high 800's and 900's.

    And I still think that some markets with low channel counts are sharing uplinks to transponders. I am in Baltimore, which has all of seven stations. It appears that those are all the channels on this spot beam transponder. However, if one goes slightly north, into the Harrisburg/York DMA, there are a total of six stations there. The spot beam that contains Baltimore obviously has enough room to add the Harrisburg/York market, unless the perceived extra space on the Baltimore transponder is being used for something else.

    One issue that somewhat proved the theory is when Columbia, SC, was added. Columbia was added to the transponder broadcasting the Greenville, SC, locals, and the transponder broadcasting the Charlotte, NC locals. There is a total of eight Greenville market stations. However, only two Columbia stations were added to the transponder, which totals ten stations on the transponder; the other four Columbia stations were paired with the nine Charlotte stations, which filled up thirteen stations on that transponder. I believe the space left on the Greenville transponder is being used for something else.

    I know there is a compounded issue here. DirecTV 4-S has 44 spot-beam transponders. However, DirecTV has two uplink centers, each able to transmit 32 uplink frequencies, for a total of 64 uplink frequencies. Remove the 26 CONUS uplinks for the satellite fleet at 101, and you are left with only 38 uplinks for spot beams. Therefore, some of the downlink transponders are being used twice, since there are 44 downlink transponders, but only 38 uplinks.

    I wonder. When DirecTV has their two new uplink sites operational (Winchester, VA and Oakdale, MN), will DirecTV use those not only for DirecTV 7-S, but to add the other six uplink frequencies that DirecTV 4-S can support at 101?

    BTW, I have modified TimF's old spot beam transponder list. I will try to get it linked over at DBSForums. That was the reason I created the above maps.
     
  6. AntAltMike

    AntAltMike Guest

    Oops. I meant geographical.

    I still don't see what you find perplexing here. As far as I can see, DirecTV 4S has 38 "transponders" dedicated to spot beam use, which is to say, it has 38 devices that take 30Mz bandwidth streams of uplinked data and "transpond", or block convert, them to the downlink frequencies, and six of those 38 transponded data streams are beamed to two spots each. I pontificated on this matter previously in a DBS Forums thread entitled See Spot. See Spot Beam Quiz

    I'm not familiar enough with the actual hardware used on that satellite to say whether the output of the part of the conversion link called the traveling wave tube amplifier, or TWTA, can be connected to two broadcast antenna/reflectors that allow the formation of two beams, or whether, as Dan Collins indicated in one of the threads on this subject, six of the Ku-band transponder outputs may be connected to two TWTAs each which I surmise would actually emit the more narrowly focused, directed beams.

    It looks like DirecTV 4S has downlink beaming hardware that forms 26 or 27 beaming boresights, and that 18 and 26 sometimes share boresights, and 4, 12 and 20 sometimes share boresights, but I just don't have enough information about the onboard hardware to say that there might be a little antenna in a reflector that is somehow optimized for 4, 12, and 20, and that the output of a TWTA is connected to it, or if three TWTA outputs are combined externally and connected to it, or if three different frequency transponder outputs are combined and put into one TWTA (doubtful, because then those would become relatively weaker transponders), of if each of 44 TWTAs emits and broadcasts its own beam and sometimes 18 and 26, and sometimes 4, 12 and 20 are concentrically targeted. But regardless of how the signals get processed AFTER they are frequency converted, I am highly confident that each of the 38, 30Mz transponder-width bands of signals, containing up to about 14 standard resolution TV programs gets block-converted to one of the six spot beam downlink frequencies, and the outputs of six of those 38 converters are somehow multiplexed to two spot beams each, regardless of how that gets done on board.

    Hughes manufacturers satellite hardware that permits onboard modulation and demodulation, but the pages on their website that I had once read describing that hardware make it seem unlikely that they are using it in this application. Regrettably, the link I had to their web page explaining that hardware and its more likely application in agile data routing, http://www.hsc.com/dsp/options.html , is no longer operative.

    And as far as even old receivers displaying these is concerned, you and I live in an area that is targeted by 28 spot beams: 26 of them are CONUS spot beams and the other two 18 and 26 are narrower spot beams, and our receivers have no problem extracting the channels it needs to produce our guides, and no problem leaving out the channels that we don't need. So if DirecTV wants to service some markets by splitting its programming over two or more shared beams, the only problem I see is that the non-plus receivers cannot call satellite B/C, which is tough cookies for them. But otherwise, if the guide software in the non-plus receivers is so limited that it can only form a guide out of channel guide numbers contained in one contiguous block, and if there is some part of that channels mappable identity imbedded in its uplinked form, then DirecTV will have to continue to do whatever carefully crafted dovetailing of numbers that it is doing now.

    Hypothetically, lets say that Transponder A contains city Albany's 900-910, and also Baltimore's 911 -914. Transponder C contains Cleveland's 907-914 and Baltimore's 900-906. As long as Baltimore is targeted by spot beams sourced by transponders A and C, then it can develop a non-overlapping programming guide even with what you believe to be the limitations of non-plus guide capability.

    But at some point soon, DirecTV just won't care about sustaining the non-plus receivers and will likely tell each of the couple of thousand customers who are in markets smaller than #50 AND who desire locals AND who still have non-plus receivers AND who are in markets getting some of their locals from satellite B/C, as is already the situation for some DISH Network subscribers, that they can get a new receiver for $50 or less or they can make their own decision on whether to leave DirecTV. They will be too small a tail to wag the dog.
     
  7. AntAltMike

    AntAltMike Guest

    Addendum.

    As I recall from the posts of a year and a half ago, 4S actually had 44 transponders on board, but 6 were intended for use as back-ups. I had concluded at the time that the 6 extra TWTAs being used to develop the 44 identified directed beams had been appropriated from those designated spare transponders, so even if there are indeed six more unused converters onboard 4S, then they couldn't be made operational to develop additional spotbeams withhout sacrificing their present use.
     
  8. moedog

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    Charlotte has 10 channels on D* and the possibility of 11 (after a power increase, WHKY-TV, Hickory NC is now must carried on all Charlotte area cable systems). That brings up an interesting question---What happens when a new station becomes eligible for carriage under SHIVA and there is no room left on a particular spot beam for the new channel?
     
  9. ChrisPC

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    Sometimes they stick it on a CONUS transponder. I read Houston has more channels than one spot beam can handle, so D* put one of them on a national beam.
     
  10. EricG

    EricG Godfather

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    Cool, How do the spot beams stay in the lines like that?? ;)
     
  11. Greg Bimson

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    Yep. You are correct. I stand corrected. There are 38 TWTAs broacasting as what appears as 44 spot-beam transponders. It renders my point moot.

    However, I still feel that there may be some space available on DirecTV 4-S. It would be cool, with newer compression technology, and the ability to split locals over two satellites, to see DirecTV add a few more markets within their spot beam satellites.

    I am awaiting to see where Huntsville is added.
     
  12. AntAltMike

    AntAltMike Guest

    If DirecTV 4S used Hughes's demod/remod transponding, rather than heterodyne conversion, and if its existing signal processing equipment could handle 8PSK, then the uplink transponders could hypothetically be enriched in such a way as to allow the 44 QPSK downlink beams to contain unique, rather than redundant, programming, but that additional capacity, if created, could never be fully utilized because then the content of each and every one of the 44 downspots would only target one region, and that region often would not need all 12-14 programs that could be squeezed into their transponder.

    In February of last year, I exchanged some correspondance on this subject with another Forum member and he was certain that the bugs had not been worked out of 8PSK by the time this satellite was engineered. Also, one of DirecTV's contract lawyers told me at about the same time that he was certain that they are just block-converting the uplinked transponders and couldn't do any exotic signal reprocessing onboard.


    I still have not received the definitive word on whether the six additional TWTAs presently in use are considered part of the six spare transponders, or whether that satellite's design included them in addition to the spares but perhaps that detail of its system archetecture has just been ommitted from the hardware descriptions available to the general public.
     
  13. Greg Bimson

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    And it does look like Huntsville has been added to the same transponder as Birmingham.
     
  14. Greg Bimson

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    DirecTV has a web page where they list the addresses of their local receive facitilities, which we tend to call points-of-presence (or POPs) here.

    DirecTV has added to that webpage Fargo, Eugene, and Wichita. I guess we can expect them to come online at some time soon.
     
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