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What is max cable run for HR20 installs with 5lnb?

Discussion in 'DIRECTV Installation/MDU Discussion' started by sgsmitty, Oct 22, 2007.

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  1. sgsmitty

    sgsmitty Mentor

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    subject says it all
     
  2. HDTVsportsfan

    HDTVsportsfan New Member

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    I beleive the rule of thumb is 125' total per run. Many here have posted having lengths longer than that. If you use a good quality cable you could probably get by w/ longer than 125. I'm not necessarily recommending longer than that, Your Mileage May Vary.
     
  3. techrep

    techrep Hall Of Fame

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    Signal lockers or powered multiswitches may extend that to 200' or so.
     
  4. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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  5. HDTVsportsfan

    HDTVsportsfan New Member

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    They will certainly help. Since I have never used those type of products I didn't even want to mention it. Thanks for the input.
     
  6. AntAltMike

    AntAltMike Hall Of Fame

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    Most, if not all, arbitrary maximum length figures you see published are the limits that the DBS providers mandate for their standard installations. I have never had trouble with any unamplified distribution lines that were under 300 feet long.

    The old rules of thumb used to be that signals left the typical LNB with a strength of about -30dBm, they lose no more than 10dB per 100 feet of RG-6 at their highest frequency, and that all receivers can reliably process signals with a signal strength of -60dBm. I haven't actually attempted to verify those signal levels and thresholds in years, however.
     
  7. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    From working in another thread, if there is a multi-switch in the system, the losses seem to need an amp for runs around 200'.
     
  8. techrep

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    I have seen some of these threads and remember the same conclusions also.

    AntAltMike's info appears to be correct but; not all cable, connectors, tuners, or installers are created equal. Losses like multiple insertion points can increase the total impedence tally of the long cable runs beyond what is expected. A single cable run of 300' - 350' with one connector at the LNB and one connector at the receiver will probably work just fine but, add two connectors at the the grounding block, two connectors at a multiswitch plus the multiswitch, and two connectors at the wall plate plus the barrel, and you have a different animal.
     
  9. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    That animal is a squirrel. :lol:
     
  10. Milominderbinder2

    Milominderbinder2 Cutting Edge: ECHELON '08

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    If the connect are tight...

    If the connectors are good and well done...

    If there are no splices...

    If the cable is not crimped or cut...

    If the cable does not have moisture in it...

    If the center core is solid copper...

    If the cable is good, newer RG6...

    If you use RG11 instead of RG6...

    You might be able to have longer runs. But the answer we should give is the one tech support would say: 125'.

    - Craig
     
  11. techrep

    techrep Hall Of Fame

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    Nice!:lol: I would classify that as a random element.
     
  12. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Well this is RF so that little sucker is running around all over the place. :)
     
  13. excalibur26

    excalibur26 Mentor

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    RG-11 should take care of runs in excess of 125 feet. Not easy to work with and not cheap.
     
  14. AntAltMike

    AntAltMike Hall Of Fame

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    Back in the late 1990s, Sonora Design bench tested a bunch of Sony receivers and they all performed reliably down to -66dBm. Around that same time, I went to a seminar at World Satellite Network's headequarters in which we padded one down to below -70dBmV before it failed, and even then, if it was padded down to about -75dBm but an inline amp was installed right at the receiver it could be recovered. DBS receivers only need an S/N ratio of about 8dB to still be processible, whereas analog signals begin to show visible degradation when the C/N drops below about 45dB, so you can more readily recover a DBS signal through post-loss amplification than you can an NTSC signal.

    The practical advice I give is that while you should always try to minimize cable lengths, if you don't see any easy way to keep it under 300 feet, don't sweat it. I have successfully tested DISH DP receivers (2,150MHz) at nearly 400 feet from the LNBs with no amplification, I only use cheap RG-6 with steel center conductors and maybe 40% braid coverage, and like most people who have been around forever, there was no such thing as 2GHz F-81 barrels for the first decade of my C-band lifetime, and they weren't readiy available even when I started using stacked DirecTV trunklines in the late 1990s, but I never had any trouble with those F-81s that just touched the center conductor at two points.

    As for multiswitch losses, I remember that a lot of the inexpensive 3x4 switches had insertion losses of three or four dB, but I thought that when I saw the specs on more modern, externally powered 5x4s that they were closer to zero loss. Does anyone have any links to the insertion loss or output port loss of any common (WB68, WB616) wideband switches?
     
  15. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    AntAltMike
    This is all good "stuff" and I believe you, but also know or have worked with members who weren't as luckily as you and needed amps & Sonora locker at short lengths than what you've posted here.
     
  16. AntAltMike

    AntAltMike Hall Of Fame

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    I would be concerned that the WB68 non-powered switches tmight be unable to sustain the voltages necessary cross the 18 volt evens threshold of about 15.5 volts at long lengths, but the last time I saw an admittedly small picture of a WB68 switch, I thought the picture had a power supply with it. Are the current production edition of WB68s externally powered?
     
  17. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Completely passive.
     
  18. AntAltMike

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    If fairness to others who turn here for advice, I, of course, have test gear to tell me exactly what I am seeing for signal levels, so I am less concerned when I deal with systems that do not have structural surplusses engineered into them, since I know what I am getting for signal strength in absolute terms.

    By the way, a few months ago, I noticed on some H20s that during the set-up regimen, you could choose between a 6x8 switch and a 4x4 switch, with the default setting being 6x8, and when the installer before me had left it in 6x8, it could not interface with the 4x4 switch. What that implied to me is that 6x8 switches and probably AU9 LNBs might be smart enough to recognize DiSEqC commands, even for the four "core" satellites, and if that is the case, then they just might be able to deliver "evens" when the voltage reaching the switch dips below 15.5 volts. I can't say that for sure, because I didn't experiment with it, but if you ever are pushing the limits on distance and failing to lock the evens, you just might want to make sure the receiver is on 6x8 switch mode, even if you don't have a 6x8 switch, because the AU9 just might connect you to the right transponders by recognizing a DiSEqC code for them.
     
  19. AntAltMike

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    I think I saw the picture on eBay. It wouldn't be the first time a seller attached the wrong picture...
     
  20. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    From what I've heard, that is used only for the 72.5 & 95 SAT dishes off the WB68 or WB616.

    To add: my AU9 has a mounting for another LNB to receive the 95 SAT signals. This is either a future or still born planned upgrade.
     
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