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DIRECTV Satellite Discussion D-14 @99W

Discussion in 'DIRECTV General Discussion' started by Sixto, Jun 17, 2010.

  1. Jun 28, 2013 #761 of 3078
    HoTat2

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    If it can be done on Ku with the bands much closer this way, why is it not well technically possible only 5-6 GHz up to separate the RDBS band at 17.3-17.7 GHz from the Ka-lo band [SIZE=14.399999618530273px]beginning[/SIZE] at a much greater than the Ku example, 600 MHz, away at 18.3-18.8 GHz?
     
  2. Jun 28, 2013 #762 of 3078
    LameLefty

    LameLefty I used to be a rocket scientist

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    Well, it's kind of a chicken-and-egg problem. Back in the 60's, the US and USSR were launching dozens of payloads a year, sometimes even dozens a month. The launch vehicles were bering cranked out like LEGOs, the ranges and tracking assets fully developed and crewed and things were really hopping. The civilian launch market doesn't work nearly as quickly but there's still plenty of excess production capacity. If the payload market for commercial launches was robust enough they could easily staff up to build and launch more vehicles. As it is, there's just no need to rush through the process like that anymore. Payloads are longer-lasting and much more expensive, which actually puts negative pressure on the launch rate - each bird costs so much and is expected to last so long, it's better to take 3+ years to do the whole thing right than accept the risks of speeding up.

    But speaking of speeding up, it will be interesting to see the Investor Relations slides in the next year or two as the legacy 101 Ku fleet starts to show its age. This was mentioned a year or so ago, along with predicted lifespans; I would expect Directv to file some stuff with the FCC over the next 6 - 12 months in order to get the ball rolling on replacements.

    They've been doing so for years. Pay better attention.
     
  3. Jun 28, 2013 #763 of 3078
    P Smith

    P Smith Mr. FixAnything

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    I did post for you perhaps, right above your post, a PCB of dish DP LNBF (CIRCULAR)
     
  4. Jun 28, 2013 #764 of 3078
    P Smith

    P Smith Mr. FixAnything

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    That LNBF (what PCB I posted) does have depolarizer in waveguide tube, it's actually a 'triangle' metal rib like a ladder.
     
  5. Jun 28, 2013 #765 of 3078
    HoTat2

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    Thanks; :)

    Wikipedia called it a "dielectric" material, but anyway the point is a component in the waveguide feed tube acts as a depolarizer to convert the incoming CP waves into linear ones for reception by H/V linear antenna probes.
     
  6. Jun 28, 2013 #766 of 3078
    James Long

    James Long Ready for Uplink! Staff Member Super Moderator DBSTalk Club

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    Then your mention of OTARD was entirely wrong. Anyways, I look forward to DirecTV introducing the LNBF package needed to receive RDBS along side their other frequency bands.
     
  7. Jun 29, 2013 #767 of 3078
    harsh

    harsh Beware the Attack Basset

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    If it represents additional bandwidth, they might.
    As I've already suggested, the RDBS payload might be used for something other than residential TV service.

    It is folly to assume that if something exists, they have an obvious plan for it and it will certainly benefit everyone. In this case, DIRECTV was on the bubble to occupy the slot to a certain extent.
     
  8. Jun 29, 2013 #768 of 3078
    harsh

    harsh Beware the Attack Basset

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    Not if they can't pull off a combination feed horn. If they need two horns to pick up the same slot and if both of them are in or near the Ka band, you're likely looking at a rather large multifocal dish.
    It would be very important, if not imperative if the band is to be used for residential service.
     
  9. Jun 29, 2013 #769 of 3078
    harsh

    harsh Beware the Attack Basset

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    Where did they share their training and experience in this thread?
     
  10. Jun 29, 2013 #770 of 3078
    studechip

    studechip Godfather

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    Well you certainly have covered about every contingency here. Plenty of room for backtracking.
     
  11. Jun 29, 2013 #771 of 3078
    Diana C

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    The bottom line is that there are MANY ways to "pull off a combination feedhorn" - many of which have already been discussed. Which approach is chosen will depend on exactly what services they deploy on these frequencies and the relative cost of manufacture for each approach. Rather than spending time declaring that it can't be done because it hasn't been done before, it might be more productive to speculate on what uses this capacity might support. It is obvious that these frequencies will be used for SOMETHING - otherwise they wouldn't be spending money on the TWTAs for their satellites.
     
  12. Jun 29, 2013 #772 of 3078
    HoTat2

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    Granted all these individual considerations probably need not be as stringent for consumer equipment, but still I'm sure must meet them at some acceptance level before moving to mass production and distribution.
    To the contrary, it would be complete folly for DIRECTV to have gone all this way in the development of RDBS and not have a well thought out implementation plan to offer it to their subscribers.
     
  13. Jun 29, 2013 #773 of 3078
    HoTat2

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    I don't recall DIRECTV ever claiming anything different than for residential service in all the documentation submitted to the FCC I've seen regarding the target for RDBS service.

    If you know of any other, please post the links, or upload it. I'd be very interested in them.
     
  14. Jun 30, 2013 #774 of 3078
    HoTat2

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    And for that matter regarding the assumed need of a new LNB, I'm not willing to totally discount the possibility we all may have missed the boat on this and RDBS receive circuits at 99 and 103 and the necessary SWiM firmware have been there all along in the current Ka/Ku LNBFs and SWiM multiswitches, fed by the same feedhorns, depolarizer, and pickup probes used by the Ka band.

    The circuits could have just been essentially dormant all this time since there were no satellite signals for them to receive except from RB-2A in those 4 spotbeam test markets.

    If this is the case, then all that's needed is a firmware update to the receivers to tune them by sending the appropriate commands to a SWiM or to receive the 2150+ MHz band signals for legacy installs

    Be nice, assuming RB-2A is active, to have someone in the southern Utah, El Paso Tx., Seattle, WA., or Alaska areas with a spectrum analyzer on the output of a Slimline to see if a new band is showing somewhere above 2150 MHz. :)
     
  15. Jun 30, 2013 #775 of 3078
    LameLefty

    LameLefty I used to be a rocket scientist

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    Please knock off the argumentative buffoonery. The FCC license is plainly for residential use. These documents have been posted in the past several times, in this thread and in the predecessor technical discussion threads. Please pay attention.

    They've been sharing their knowledge, which is even better. Unlike you, who keep spreading random FUD-filled comments that have no basis in fact.
     
  16. Jul 1, 2013 #776 of 3078
    slice1900

    slice1900 Well-Known Member

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    They would have had to be planning to potentially use the RDBS bands back when they spec'd the KaKu LNB. They designed it to receive from 18.2 to 20.2 GHz, so designing it for a 2 GHz width is obviously possible. Perhaps designing it for a 3 GHz width would not add much cost, and future proof it in case they one day made use of this bandwidth. They'd have to place it above 2150 MHz on the cable, so they'd need cables tested for this. Don't they require cable that's swept tested to 3 GHz? Why do that with a ceiling of 2150 MHz?

    If I had to bet, I'd say the current dishes, LNBs, and multiswitches that work with KaKu now will work with the new RDBS satellites without modification. The receivers will receive firmware updates to "see" the new satellites after they're launched, and the average customer won't even know this happened, just that there are more channels with better quality, 4K, more local subchannels or whatever they use all that bandwidth for.

    According to this article I found, the first application to use RDBS bands in this way occurred in February 2005, back when the Slimline and KaKu LNBs were still in development and could have been easily future proofed for this new technology. Its not quite clear from the article (I couldn't find the "2002 article" he referenced) whether the DBS allocation scheme from 2002 already included the ability to use RDBS bands and it is just taken this long to get around to it, or if that was only something potential that the FCC still had to approve after the first application in Feb 2005.

    http://www.cedmagazine.com/articles/2005/07/dbs%3A-the-questions-are-many
     
  17. Jul 1, 2013 #777 of 3078
    HoTat2

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    That's personally the direction I'm leaning towards myself. That the capability, hardware-wise at least, has always been there. I mean I realize other very knowledgeable posters here in the past have claimed it isn't in the current installed base of LNBFs and SWiM switches. And others have even published photographs of the internal view of the Ka/Ku LNBF. But unless we can see the actual schematic diagrams of the LNBF to know for sure, and DIRECTV is not about to publish those due to corporate confidentiality, there's no way to be "absolutely" sure the capability isn't there.
     
  18. Jul 1, 2013 #778 of 3078
    P Smith

    P Smith Mr. FixAnything

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    If the LNBF is capable to get RDBS' range AND some sats at 99W or 103W transmitting the signal, we should see it.
    The main question if the KaKu LNBF block has _third_ LOF to get the IF signal in a range say 2.35...2.75 GHz?

    As we're knew LOF2 for current Ka ranges is 18.05 GHz, so using it for different range (RDBS is still Ku) would produce overlapping signal in IF signals [350 MHz...750 MHz] to Ka-Lo.

    Using LOF1=11.25 GHz would not do the required transposing as it will end-up at not usable range 5.05...5.45 GHz
     
  19. Jul 1, 2013 #779 of 3078
    HoTat2

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    That's my guess;

    The RDBS L.O. would have to be around 14.95 GHz..

    Correct, it would have to be a another L.O., not the same 18.05 GHz one used for the Ka band.

    I think you meant "11.25" GHz for LOF1 :)

    But to summarize for a prospective Ka/Ku/RDBS LNBF;

    Ku 101 and 119 L.O. = 11.25 GHz

    Ku 110 L.O. (SL-5) = 11.542 GHz

    Ka 99 and 103 L.O. = 18.05 GHz

    RDBS 99 and 103 L.O. = 14,95 GHz?
     
  20. Jul 1, 2013 #780 of 3078
    Diana C

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    And, of course, this is only an issue for the cable from the LNB to the SWiM (assuming we are even talking about an external SWiM). The output of the SWiM is always in the 950 - 2150MHz range, regardless of the input.
     

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