How To Diplex OTA with the AT9 dish & MPEG-4

Discussion in 'DIRECTV Installation/MDU Discussion' started by Cap'n Preshoot, Aug 19, 2006.

  1. Apr 7, 2007 #61 of 323
    Cap'n Preshoot

    Cap'n Preshoot Godfather

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    Help me understand. Isn't transmission line attenuation directly proportional to the frequency? Ergo if it's working with Ka high, wouldn't it be a logical expectation for it to work equally well if not better @ Ka-lo?

    If we keep listening to the naysayers they will have us all installing nitrogen-pressurized heliax cable for the downlead. Judas Priest, it's just TV. :eek2:
     
  2. Apr 7, 2007 #62 of 323
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Coming out of the BBC, the frequencies will be around 2 GHz. If D* wanted to send these frequencies through the coax that far, they would have put the BBC in the dish. Since they didn't. I think it points to the fact that some cable runs will be too long for good signal levels to get to the receiver [and why the BBC is designed to be mounted at the receiver].
    There are three frequency "blocks", currently we aren't using the 1650-2150 MHz that will come out of the BBC.
     
  3. Apr 7, 2007 #63 of 323
    Michael D'Angelo

    Michael D'Angelo Lifetime Achiever

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    I do have a question about that. Not saying you are wrong but with the SWM you don't use the BBC because the switch takes care of it for you. D* wants the SWM less then 40' from the dish and you can run up to 100' from the SWM to the receiver.
     
  4. Apr 7, 2007 #64 of 323
    veryoldschool

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    And the SWM now controls what frequencies are being used, so all of the conversion is done in the SWM. The problem comes without the SWM.

    Edit: or to put it another way..the SWM is the device that wasn't put in the dish to have all of the conversion & selection done in the dish, so the IF coming out of the dish to the receiver wouldn't have large cables losses..
     
  5. Apr 8, 2007 #65 of 323
    Cap'n Preshoot

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    Well it would seem they're finally getting wise to the fact that not everyone has the luxury of being able to place their dish within 100 cable feet of the receiver. Personally I always thought 100' was borderline excessive for the L band (I.F.) frequencies and RG6, but as we've seen these forums are chock-freakin' full of dime store experts who (often vehemently) profess you can go 200' and more.

    Cap'n Preshoot
    Former FCC 1st P1-17-11478
    Comfortably retired
     
  6. Apr 9, 2007 #66 of 323
    frozenpenguin

    frozenpenguin Cool Member

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    The lack of any available SWM solution is the only thing that's been holding be back from getting the HR20. (Drilling & more cable is not an option) Luckily, I just found this thread and think I'm going to jump in now with the HR20 and then get the SWM, if needed, whenever it comes out.

    A couple questions though. Right now I have 2 coax lines coming in and I'm diplexing on both. One is diplexed for OTA and the other is diplxed for Comcast cable internet. I've run this setup for years with zero problems. Will the soution described in this tread work for the cable modem diplex as well? Also, let's say for some reason this doesn't work for me, can I just switch back and use the same diplex setup I've been using for OTA & Cable Internet? Will the HR-20 still function? Is the only thing I would loose be the HD Locals or anything else? Thanks for any help.
     
  7. Apr 9, 2007 #67 of 323
    Michael D'Angelo

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    I don't know about the internet but I do have one of my HR20's hooked up to a line that is diplexed with comcast cable on the same line. No problems as of right now but will probably have problems when the new HD channels are available.
     
  8. Apr 9, 2007 #68 of 323
    veryoldschool

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    Will "+1" & add that SWM "should" make it still work with the new channels from the new SATs. FWIW
     
  9. Apr 9, 2007 #69 of 323
    frozenpenguin

    frozenpenguin Cool Member

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    By "problems" do you mean that the HD channels won't work or that my internet will be broken? I can live without a few HD channels until SWM comes out, but I work from home and can't live without internet.
     
  10. Apr 9, 2007 #70 of 323
    veryoldschool

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    OTA & cable modems use the same frequencies as the up coming SATs will, so they can't go on the same line [and work].
     
  11. Aug 7, 2007 #71 of 323
    JustRob

    JustRob Cool Member

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    I believe cable modems (CM) use a span of 320kHz-3.2MHz band in the 5-42MHz span for upstream and any 6 MHz channel between 300-864MHz for downstream (of course the cable provider would make sure that the analog, digital, and CM frequencies don't overlap). This is from going to Wikipedia, search for cable modem, then go to DOCSIS, download RF specs for DOCSIS 2.0 and see 4.2.1 (sorry can't post URL due to 5-post min newbie).

    I've used a diplexer for sat (950-2250MHz) on one port, and 5-860MHz for the CM, using one cable line.

    CORRECTION: Clearly you could only do sat and CM if you have the new SWM/FTM multiswitch. My cable modem (DOCSIS 2.0) is actually using 609MHz DS and 33MHz US so it wouldn't work unless I had a SWM MultiSw. Without a SWM MS, if you can configure your network so that you can successfully use the old diplexers (and thus not the frequency band 250-750MHz), you could use your CM on the same wire (i.e., between the BBC output and the STB). You probably can't do CM, sat, and OTA on the same coax line wire though, unless you got some kind of fancy triplexer (they are becoming available for MoCA applications - search for Soontai - they might have something applicable).
     
  12. Aug 7, 2007 #72 of 323
    veryoldschool

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    :welcome_s to the forum.
    My cable modem download is 99 MHz & upload is 20 MHz.
    SWM will work with it but the non SWM BBC may not as it is supposed to be mounted close to the receiver [reducing the usable length of diplexed coax. Now if the Cable company will filter out all but the ISP feeds then you can work some tricks, but if they don't then you will have more signal than just you ISP feed to block and yet try to pass all of the frequency blocks from the dish.
     
  13. Aug 7, 2007 #73 of 323
    Kansas Zephyr

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    My question is, how hardy are the BBCs?

    If I try this solution, I'm forced to put the BBCs in the "cable box" on the outside of the home, since this is the entry point for my existing single coax runs.

    It's a weather-resistant box, definitely not weather-proof.

    The runs from the BBCs to the HR20s would be <20' to two locations, but more like 50' to the third.
     
  14. Aug 7, 2007 #74 of 323
    Crypter

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    I don't get it.

    I have 2 HR20's with OTA Ant for HD Locals through a Diplexer.

    Currently I HAVE both BBC's attached to each receiver directly (ie. After the DIPLEXER has split the OTA and SAT signals).

    So far I get the searching for Sateelite Screen on both tuners on both receivers without a problem. As far as I know that means they are working properly (using the BBC test channel 499).

    I did nothing special for this to work so what is with this thread?
     
  15. Aug 7, 2007 #75 of 323
    JeffBowser

    JeffBowser blah blah blah

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    I'm doing it (diplexing with bbc) successfully, and further more, I am doing it on a 50foot run of 33 year old rg58, a total of 160 feet from the dish. Now that being said, I suspect it won't work after Spetember.
     
  16. Aug 7, 2007 #76 of 323
    Kansas Zephyr

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    The issue isn't today.

    It's "tomorrow" when D10 and D11 (the satellites, not the receivers) go online. Then there will be a "conflict" between the OTA signals and the new B-band signals.

    You will lose your OTA diplexing when that happens, with your current setup, from what I've gleaned here and from other sources.

    (asking the forum) Am I right?
     
  17. Aug 7, 2007 #77 of 323
    veryoldschool

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    Quite simple:
    There currently are no signals coming down the coax in the 250-750 MHz band. [no conflict].
    The "whole issue" is when there will be signals coming from the Ka-lo band.
     
  18. Aug 7, 2007 #78 of 323
    veryoldschool

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    More reasons to move to the SWM option when available.
     
  19. Aug 7, 2007 #79 of 323
    veryoldschool

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    You were posting at the same time as myself.
    Yes, you are correct.
     
  20. Aug 7, 2007 #80 of 323
    JeffBowser

    JeffBowser blah blah blah

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    I suspect the SWM may even have issues with the ancient cable. Even I don't want to use that old cable, but I have had 3 cable installers look at the job and decline. Concrete house, plaster and lathe interior walls, and a low, hurricane reinforced roof makes for a nasty job of replacing cables. The last set I replaced I had to wait until I had half the house remodeled at the point where the ceiling drywall was removed. That sure made it easy :lol:
     

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