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DIRECTV Satellite Discussion D-14 @99W

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

  1. Jul 15, 2013 #821 of 3078
    HoTat2

    HoTat2 Hall Of Fame

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    Los...
    Well, the Dish Plus L.O.description I gave was a side issue which perhaps I really didn't need to go into in any depth.

    Just suffice it to say briefly AIUI, on the Dish 500+ and 1000+ LNBF each Dish Pro (DP) or Dish Pro Plus (DPP) LNBF actually uses two L.O.s due to the frequency stacking. 10.75 and 13.850 GHz to convert the 11.7-12.2 GHz FSS band and 11.25 along with 14.350 GHz to convert the 12.2-12.7 GHz BSS band.

    But none of this is relevant to the issue.

    Again I agree, the RDBS band will need its own L.O. for reception

    The present 18.050 GHz one used for the Ka bands is useless for it.
     
  2. Jul 15, 2013 #822 of 3078
    James Long

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

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    Funny ... because you're the one that made the claim a few pages back that a RDBS dish couldn't pass OTARD protection.

    They don't have to prove it to you now - just wait and buy the dish/LNB. :)
     
  3. Jul 15, 2013 #823 of 3078
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "Funny" wouldn't be my first choice. Ignorant might be better since the current dish works from Ku thru Ka and it's the LNB where any work will be needed.
     
  4. Jul 15, 2013 #824 of 3078
    studechip

    studechip Godfather

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    Virtually all of this is WAY over my head. From a "what makes sense" point of view, don't you all think the engineers at Directv figured this out a long time ago otherwise they wouldn't have started with RDBS in the first place? They can't reasonably replace all of the lnbs just to open up a new band. It has to work with what they already have in place. Make sense?
     
  5. Jul 15, 2013 #825 of 3078
    HoTat2

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    Los...
    My guess would be if RDBS is intended for mainstream service, then yes the current LNBFs likely have the receive capability already built in. If intended only for niche programming like moving the World Direct service from a separate dish aimed at 95w or something, then a new LNBF swap out program is feasible given the comparatively small number of subscribers needing to be converted.
     
  6. Jul 16, 2013 #826 of 3078
    JoeTheDragon

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    what about useing it for 4k / 8K that may need new boxes + new LNBF?
     
  7. Jul 16, 2013 #827 of 3078
    P Smith

    P Smith Mr. FixAnything

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    what is that ? is D14 expecting carry the channels ?

    the 4k/8k is matter of _using_ transponder's bitrates, not LNBF and new STB will come eventually
     
  8. Jul 16, 2013 #828 of 3078
    James Long

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

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    I have not looked at the timeline to compare the design and release of the current LNBFs vs the development of RDBS service. RDBS was tested from a satellite a couple of years ago (internal testing) but isn't the current LNBF older than that? Putting the development cost in to the LNBF would have been a gamble.

    On the plus side of that argument DirecTV did invest in a satellite that allowed them to test RDBS on a limited basis. But designing the current LNBFs (which have been out for many years) in the hope that they might someday use the band? Producing and distributing LNBFs for a band that they were just applying for the licenses for? That would be surprising.
     
  9. Jul 16, 2013 #829 of 3078
    inkahauts

    inkahauts Well-Known Member

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    Unless it was relatively easy to include that ability with little cost.
     
  10. Jul 16, 2013 #830 of 3078
    studechip

    studechip Godfather

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    Could be James, but I'd guess that the extra costs on them would be less than the cost to replace all existing units.
     
  11. Jul 16, 2013 #831 of 3078
    HoTat2

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    Los...
    Well ... the original LOAs for RB-1 (S2711) and RB-2 (S2712) were originally filed with the FCC back in '06.

    http://licensing.fcc.gov/cgi-bin/ws.exe/prod/ib/forms/reports/swr031b.hts?q_set=V_SITE_ANTENNA_FREQ.file_numberC/File+Number/%3D/SATLOA2006090800099&prepare=&column=V_SITE_ANTENNA_FREQ.file_numberC/File+Number

    http://licensing.fcc.gov/cgi-bin/ws.exe/prod/ib/forms/reports/swr031b.hts?q_set=V_SITE_ANTENNA_FREQ.file_numberC/File+Number/%3D/SATLOA2006090800100&prepare=&column=V_SITE_ANTENNA_FREQ.file_numberC/File+Number

    Anyone remember the time around when the Ka/Ku Slimline LNBFs first appeared?

    And as I said I find it hard to believe that at least 17.3-17.7 GHz rejection circuity is not incorporated in the current units Ka band receive circuitry, since whenever the RDBS payloads at 99 and 103 are fully transmitting those signals are going to be roaring in at the Ka-lo band's image frequencies resulting in a spurious 350-750 MHz conversion band overlapping with the desired Ka-lo band at 250-750 MHz.
     
  12. Jul 16, 2013 #832 of 3078
    slice1900

    slice1900 Well-Known Member

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    If they filed in 2006, they surely must have had some discussions internally about this for a while before filing. I assume that making such filings with the FCC is not a decision taken lightly. I posted a link a few pages back that documents the FCC discussing permitting RDBS for residential satellite at least as far back as 2002. It seems between this fact and Directv's September 2006 filing date, we can be certain that they had enough advance knowledge they could have included RDBS capability in the KaKu & SWM LNB design, if they wished.

    Whether they actually did so or not, we probably won't find out until we see what type of programming the new satellites/bands are used for and whether customers for that programming need new LNBs or not.

    While I don't know enough about RF to fully understand your last paragraph, if there would be potential interference between RDBS and current Ka band LNBs, you're right they would have had to design for that. The fact they are planning to use RDBS implies that the current LNBs were in fact designed to either filter out the RDBS frequencies, or to receive them. Unless it would cost a lot (>$10 per LNB) to receive them versus filter them, it will have been designed to receive them.
     
  13. Jul 16, 2013 #833 of 3078
    P Smith

    P Smith Mr. FixAnything

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    If you have seen how the 250...750 MHz is using by Ka-Lo tpns, you wouldn't worry too much about "roaring" - there are plenty free chunks to fit a few RDBS transponders without overlapping.
     
  14. Jul 16, 2013 #834 of 3078
    HoTat2

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    Los...
    Looking at this example spectrum display from a SL-5 LNBF output by Sonora Design Associates P. Smith, I have to say its hard to see where there's room for such interleaving with its image frequencies.

    Notice how the Ka-lo band spectral energy shown on the left side of the displays looks a pretty dense population.

    Pages from SWM_DESIGN_CH11 (1).jpg

    Got some examples as to where in the low band these energy gaps are located.?
     
  15. Jul 16, 2013 #835 of 3078
    P Smith

    P Smith Mr. FixAnything

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    Oops, perhaps I've seen the spectrums on my SA long time ago and reversed the pictures as my SA have only 500 Mz max for full screen. Well, back to square one.
     
  16. Jul 17, 2013 #836 of 3078
    Sixto

    Sixto Well-Known Member

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  17. Jul 17, 2013 #837 of 3078
    harsh

    harsh Beware the Attack Basset

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    As I've said repeatedly, the current dish doesn't try to grab signals that are closer together with respect to wavelength from the same satellite. DIRECTV's testing has spoken to Ku vs Ka using materials that differentiate based on the difference in wavelengths that is less between Ku and RDBS. Thinking of the proposed situation at 101W, we know that to be optimal, the antennae need to be arranged at different distances from the ground plane and of different lengths. Nobody has offered what the tolerances are but I wonder how they might arrange the little buggers and how they would keep the RDBS antenna from getting blasted by the Ka signal and vice versa.

    Finally, all this has to be done in a way that doesn't interfere in any measurable way with the functionality of the existing AT-9 and AU-9 configurations.
     
  18. Jul 17, 2013 #838 of 3078
    harsh

    harsh Beware the Attack Basset

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    The claim was that a combination Ku-RDBS-Ka LNB assembly was not in evidence (still true) and as such, might require multiple feedhorns and a special double dish to grab the 101W slot.
     
  19. Jul 17, 2013 #839 of 3078
    slice1900

    slice1900 Well-Known Member

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    This is the key to all of this. Any theory that has as a consequence that Slimline LNBs will have their reception of existing signals degraded once the RDBS satellites are lit up, due to interference, is obviously wrong. Either the Slimline LNB avoids this through its design, by filtering or properly receiving these signals, or there will be no signal interference.

    Didn't I read that there are already some test RDBS signals being broadcast from one of the existing satellites? If that's the case, we already know that RDBS doesn't interfere with reception of Ka band with either the Slimline or AT-9.

    That says nothing about whether either or both will be able to receive RDBS signals without a new LNB or entirely new dish, but it would show that both signals can coexist without causing any problems for current equipment.
     
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  20. Jul 17, 2013 #840 of 3078
    HoTat2

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    What is so "optimal" about the placement of the antenna probe at 101 as opposed to those at 99 and 103 for the Ka (and possibly RDBS) bands? :confused:

    And so what if the "same" antenna probes are blasted by both the RDBS and Ka bands as long as their outputs are directed to separate receive circuits?





    For all we know, this may have already have been satisfactorily evaluated by the RB-2A payload on D12 at 103 which is spot-beamed into those four (possibly test?) markets in west Texas, southern Utah, Seattle, WA.. and Alaska.

    Any subs. report interference to their Ka-lo band HD channels in those markets? :)
     

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