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What are BBC's ??????

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by chillifier, May 17, 2010.

  1. chillifier

    chillifier New Member

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    Sep 7, 2009
    I just purchased a h24-100 and it is on a legacy system. I think I need a BBC for it because I do not see satellites 99 & 103. I do not know what BBC's are. Please Help
     
  2. ndole

    ndole Problem Solver

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    First off to :welcome_s DBSTalk!
    BBC stands for Broadband Converter. Basically, when your KaKu [or HD] Dish receives signals from the 99 and 103 satellites, those signals are at such a high frequency, that they would confuse a standard [non-HD] receiver. So, what your dish [if you have a KaKu] does is down convert those signals, so that any standard receivers installed in your system won't malfunction. A BBC's function is to up convert those same Ka [HD] signals, so that your HD receiver will be able to see the 99 and the 103.
    Give Directv a call at 800-531-5000. They will send you BBC's. Likely free of charge.

    Hope this helps!
     
  3. chillifier

    chillifier New Member

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    Sep 7, 2009
    do the new H24 receivers require them ???????
     
  4. Billzebub

    Billzebub Godfather

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    I believe they do if you're not on a SWIM system.
     
  5. ndole

    ndole Problem Solver

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    Correct. of you have a legacy [non-SWiM] system, then you will need a BBC for your H24. Only the H23 and HR23 receivers don't require BBC's on a legacy system.
     
  6. chillifier

    chillifier New Member

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    Sep 7, 2009
    Thank you all. Called DirecTV and they told me I did not need a BBC. I took one off my HR22 and put it on my H24, reran satellite setup and WALA, Works great. Thank you all for the very fast response.
     
  7. dclarke

    dclarke AllStar

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    Yikes, on craigslist I think it means something entirely different, not that I would know
     
  8. matt

    matt New Member

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    Call them back and ask for some for your HR22 since the CSR you got doesn't realize that some people are using a new receiver on a legacy system. It will just be easier to say they are for the HR22 than trying to educate them... :rolleyes:
     
  9. David MacLeod

    David MacLeod New Member

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    isn't it B-Band converter and not broadband converter?
     
  10. evan_s

    evan_s Hall Of Fame

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    Yes it is B-Band converter. The Ka-Lo or Ka b get placed at 250mhz-750mhz which everything but the HR23 can't tune to. The BBC, when activated. Takes the 250mhz-750mhz signal and moves it up to 1650-2150 replacing the Ka a band or Ka hi. This is why placing the BBC before diplexing OTA signals in works even if it isn't supported.

    Interestingly enough it also means that you will be able to get HD channels from D12 with out the BBC since it's Ka hi. =)
     
  11. CCarncross

    CCarncross Hall Of Fame

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    Jackson

    What do you think the "B" stands for?

    ;)
     
  12. evan_s

    evan_s Hall Of Fame

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    It doesn't stand for anything. The Ka band is split in to 2 blocks, hi and lo or A and B.

    http://www.dbstalk.com/showthread.php?p=869690#post869690

     
  13. TomCat

    TomCat Broadcast Engineer

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    Lots of info here in this thread, but lots of misinformation, too.

    Ka stands for "K above", which means it is the band just above (in frequency) the K (Kurz) band. Ku stands for "K under" which means it is the band just under (below in frequency) the K band. There is no "B" band, and no "Kb band". The "B" in BBC does not stand for "B". BBC is an acronym for "base-band converter" because it is used to convert part of Ka, (which has been converted to baseband frequencies in order to be transported by an L band system) back up to L band.

    It is easiest to understand if you first look at a conventional L-band distribution system from antenna to receiver, and understand the history that led to the need for BBCs. When I started in satellite technology, commercial use was of C band only. C band frequencies were transported from the LNA all the way to the receivers. This was not practical, as these were 4 GHz signals and the losses were significant over any distance and they needed expensive waveguides to transport them. Satellite was growing and needed more uplink space, and Ku was eyed, but it was even higher in frequency and so distribution at frequency seemed impractical.

    Enter the LNB (circa 1982). The LNB was a low noise amplifier (LNA) with a block converter tacked directly onto the output. It used a heterodyne oscillator at a frequency which would block-convert the entire C band 4 GHz bandwith (approximately 3700 MHz to 4200 MHz) in one step to L band, which is 950 MHz to 1450 MHz. This allowed transport from antenna to receiver using conventional 75-ohm RG6 cabling, and allowed cheap power dividers (hybrid splitters) for distribution.

    L band was a huge improvement, and is still used today in virtually all DBS and most commercial TVRO systems, including DTV. Until Ka, DBS used Ku exclusively, which meant a 11.7-12.2 downlink was block-converted at the LNB to 950-1450 MHz. Notice that this is a 500 MHz bandwidth, as was C band.

    Ka, however, has 2 non-adjacent bands, which allows a total bandwidth of 1 GHz (which doubles the number of channels/slots that can be delivered). Since the legacy L band system for DBS has a flat-enough and wide-enough bandwidth to actually handle frequencies well-below its typical 950-1450 range (on existing L band distribution systems), DBS used two heterodyne conversions in the LNBF [see note below], one for each band of Ka, which allowed one band to convert naturally to 950-1450, and the other band to convert to the 250-750 MHz range which overlapped what were were normally the frequencies that L band channels were finally converted to for IF use by the DVB tuners in the receivers/IRDs (the "baseband" frequencies handled by the tuners after conversion from L band to IF).

    This is why you will get some of the channels from the hybrid sats but not all, until you add the BBCs (or use a receiver with wide-band tuners, which means they can handle a range of approximately 200-1450 rather than 950-1450, essentially converting each band separately to IF, similar to how the Ka LNBF converts each Ka band to a separate intermediate band of frequencies).

    [note: above is the information that was given me, but I can not quite confirm it. There is an alternate theory that the entire Ka downlink is converted from 18.3-18.8 and 19.7-20.2 to 250-750 and 1650-2150 by a single heterodyne converter on the LNBF. This would make more sense in that the LNBF would be simpler, but would not jive with the concept of the BBC being needed for conversion of the lower band but no converter needed for the higher (up to 2150) band, unless legacy tuners can already handle 2150, which is doubtful. There is one way this might make sense, however, which is if DBS is using only the lower Ka band along with the Ku band in a hybrid mode from each KaKu sat, which would put Ka at 250-750 after L band conversion and not require the other Ka band, which would have been converted to 16-50-2150. That would mean Ka occupies (after conversion) 250-750 while Ku occupies (after conversion) 950-1450.]

    But the old legacy tuners look for L band frequencies (950-1450) only. The BBC is the workaround that allows legacy tuners to see frequencies that were originally Ka frequencies but were converted at the LNB to baseband frequencies below L band (but still transported by the L band distribution).

    When the upper part of Ka is desired (which are converted to L band) the BBC is in "pass-through" mode, allowing L band to pass directly. When a Ka channel that was block-converted to below L-band is chosen, it sends a voltage signal to the BBC to switch on, and it converts the 250-750 MHz band (original lower part of the Ka band converted to below L band) back up to 950-1450.
     
  14. P Smith

    P Smith Mr. FixAnything

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    "it sends a voltage signal to the BBC to switch on" - it's not.

    Search for "E202" and "E203" to know little more.
    DiSEqC
     
  15. evan_s

    evan_s Hall Of Fame

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    Interesting TomCAT but you do seem to have some incorrect information in there.

    The Ka Hi is at 1650-2150 mhz and this is also where the BBC shifts the Ka Lo when it is activated.

    [​IMG]

    Legacy tuners can obviously handle this as you can get the Ka Hi channels with out the bbc installed. Prior to D12 going operational, this was only some locals coming from the Spaceway sats but now anyone should be able to test this and get the national channels that are now on D12. This also has to be the case to allow the receivers to continue to receive guide data as this is only coming from 101 or 119 (depending on the dish and what part of the stack plan you are on, if Ka anything replaced them at the center frequency the receiver would loose the ability to receive the guide data).

    Dish has been using the 1650-2150 mhz band for their receiver since they switched to the DISH Pro switches which stacks both polarities from a single slot so tuners capable of going that high have been in use for a while.
     
  16. TomCat

    TomCat Broadcast Engineer

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    Well, that clears up the mystery of which theory presented to me is the correct one. Thanks much for that final piece of the puzzle. I was not aware that they had yet gone to the 1650-2150 band, but that would explain why the allowed cable lengths are shorter than they used to be (and probably why they insist on no RG-59).

    Out of curiosity I just checked wikipedia and it says that L band is "1 to 2 GHz", so I guess this is still technically L band. Pro use of L has always been only 950-1450.

    Seems like between us we might have nailed it. :grin:
     
  17. evan_s

    evan_s Hall Of Fame

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    The dish pro documentation I read stated that it stacked the odd and even tps sending both for an orbital location at the same time and used the standard 950-1450 for the odd and the 1650-2150 for the even. They use DiSEqC to control which orbital slot they select and can always send 18v which is why they don't need solid copper core(don't have to worry about the dc loss as much).

    Dish pro plus seems to add the ability to control the 2 bands separately so the 950-1450 can be used for the first tuner and the 1650-2150 for the second tuner using a single line to drive a DVR.
     
  18. P Smith

    P Smith Mr. FixAnything

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    :backtotop:

    What about SUP-2400 documentation ?
     
  19. tkrandall

    tkrandall Hall Of Fame

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    That table is the stack plan for a SL5 LNB. For a SL3 LNB, replace the 119 odd and 110/119 even items in the right two colums with 101 odd and even, as the SL3 always passes 101 feeds (with 22 KHz tone from receiver/multiswitch or not)
     

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