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Yet another SWM question/problem, please help

Discussion in 'DIRECTV Installation/MDU Discussion' started by Non Jeff, Oct 7, 2009.

  1. Oct 7, 2009 #1 of 49
    Non Jeff

    Non Jeff AllStar

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    I have spent a week re-reading everything on SWM8 installations, and I'm stuck. Sorry for yet another question on SWM installation, but I just can't figure this out. I know I'm overlooking something, and hope someone can spot my error.

    Last summer I installed a SWM-8 from my Slimline 5 dish, and round 72.5 dish since we still got locals from that satellite at the time. I kept my WB68 multiswitch and installed it in parallel for future use.

    My equipment at the time were three H10's, an HR20, two H20's and two H23's. I also use off-air. Installation was a breeze thanks to all the great info on dbstalk, and things worked flawlessly.

    I installed my SWM-8 inside my home near my cable distribution center. The four runs from the dish to the SWM-8 are about 20-25 feet. I installed the PI about 20 feet from the SWM-8. I used only one SWM port and terminated the other, running it to a SWS-8 splitter. I put my three H10's on the legacy ports and diplexed in off-air. I put the HR20, the two H20's and two H23's on the SWS-8 splitter and terminated the unused ports there. I like to use off-air on all my HDTV's from time to time, so I diplexed out at the TV's. No problems.

    My locals are switching from 72.5 and so I was notified I needed an equpiment upgrade, which in my case was just new boxes to replace the H10's. When the installer arrived last week, he looked at my setup with amazement. He knew somewhat about the SWM-8 but had never seen one. He said he was really only authorized to set up my new H23's through the WB68, which I expected. So we did this without any problems running them through the WB68. However, I do want to keep off-air, so after he left I then re-configured my setup.

    Obviously I previously had six tuners to my SWM-8, and now I have nine. Therefore I decided to run my two old H20's through the WB68 multiswitch using the BBC's, leaving my SWM-8 with seven tuners to feed.

    So, to recap, I have the SWM-8 and WB68 installed parallel from my Slimline 5 dish about 20 feet inside the house. PI is installed about 20 feet from my SWM-8. One SWM port on the SWM-8 feeds a SWS-8 splitter, the other is terminated. Antenna connected to the off-air port. Flex port is detached since I don't need the 72.5 sat anymore. No legacy ports used anymore.

    Two H20's attached to the WB68 with the BBC's installed before off-air is diplexed in. Both were set up without problems and work fine.

    Five H23's and one HR20 connected to the SWS-8 splitter, terminated the two unused ports on the 8-way splitter.

    Diplexer used at each HDTV where the H23's are, with off-air to the TV, and sat to the H23.

    Here's the problem. IF I use off air, I have trouble getting sat signals to any random box. Usually about 3 / 5 boxes work, the other two won't. This changes from box to box randomly, for no apparent reason. If I disconnect antenna from the off-air port of the SWM-8, OR take out the diplexer at each location, then all work fine.

    Why is diplexing screwing things up? I can't figure this out. I'm using D*-approved, high frequency splitters and diplexers everywhere. I'm using high-quality compression fittings and RG6 everywhere. I'm stumped, and can't figure out what I'm overlooking.

    Any ideas? Any help would be greatly appreciated. Thx.
     
  2. Oct 7, 2009 #2 of 49
    BattleZone

    BattleZone Hall Of Fame

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    There's no such thing as a DirecTV-approved diplexer, because diplexing is totally unsupported.

    Having said that, is works. But the issue that you're running into is signal loss. Every time the signal is split or diplexed, you lose a HUGE amount of signal, and you've got several cascasded high-loss splits going on.

    At the very least, you need a pre-amp on your antenna, and even that may not be enough, but it's the right place to start. If that still isn't enough, you'll need a distribution amp as well. This is before the signal even gets to the SWM8.

    You need to raise your signal level by 15-20 db. Decibels (db) are measured logrithmicly; a 10 db loss means only 1/10th of the signal is getting through. A 20 db loss means only 1/100th of the signal is getting through, etc.
     
  3. Oct 7, 2009 #3 of 49
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I think you just found out why DirecTV no longer supports diplexing. The SWM8 is for commercial [MDU] installs.
     
  4. Oct 7, 2009 #4 of 49
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    You may have missed this:
    "Seems like" there may be a problem with the 2.3 MHz comm signal, but :shrug:
     
  5. Oct 7, 2009 #5 of 49
    veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    I'm not sure if this would make it work, "but":
    You're losing 3dB by not using the second SWM output with the termination.
    If you were to change to 4-way splitters and use both outputs, the levels would be higher. Would this be enough? :shrug:
     
  6. Oct 7, 2009 #6 of 49
    dettxw

    dettxw MRVing

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    Very nice write-up.
    Like stated before, diplexing is not supported but usually works. Don't think that you mentioned the diplexer model though. Any chance that the diplexers are not up to snuff?

    BTW, start thinking about separate OTA runs as you may want to take advantage of future capabilities that will use those frequencies.
     
  7. Oct 7, 2009 #7 of 49
    Non Jeff

    Non Jeff AllStar

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    Diplexers are the Perfect Vision PVDP2 I bought from SolidSignal, sold as "Directv Approved" back in the day when Directv supported diplexing.

    That's probably a good idea to try using both SWM ports with 4-way splitters, VOS. Thx. I will give that a try.

    Yes, my problem is not with my OTA signal strength (which bats about 100% with my pre-amp), its with sat signal strength which somehow is getting blocked by diplexing OTA. What I can't figure is why my previous system had zero problems pushing satellite to six receivers while diplexing, but now adding just one more tuner to the SWM-8 seems to have hurt sat signals while diplexing. Take out the diplexing, no problem. But I have great OTA and enjoy watching it for certain things over MPEG4 signal, not to mention getting stations not offered via Directv. Would hate to lose it. I already knew Directv does not support any diplexing now, but its proven to still work, and in theory, should work. I just can't figure out what's wrong. Its a head scratcher...

    Could improper grounding of the SMW-8 have this affect? I know there is some kind of polarity issue going on too, as testing often shows a loss of even voltage at times from certain satellites, primarily 99 and 103c.
     
  8. Oct 7, 2009 #8 of 49
    netraa

    netraa Godfather

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    I'm thinking out loud here so some of the guys that know this stuff a lot better than me can help me out on this...

    each different IRD model, and each IRD itself for that matter, has a different RF threshold. the point at which it can or can not 'hear' the signal being offered. Somewhere in that is the signal to noise ratio threshold for the IRD.

    The OTA diplexing is 'noise' because it is outside of the desired spectrum for the IRD. Yes, it's good noise for something else, but it is noise.

    Perhaps the H23's just have a lower RF threshold and your one more split/diplexer is pushing them over the limit.

    If I am understanding what you did right, you changed out the H10's to 23's adding them to the swm and moved the 20's to the 6X8.

    your move did more than add 1 tuner to the swm8:
    you added 3 different runs of coax, untested on the swm8 to the system (the H10's)
    removed 2 lines that were in service. (the h20's)
    changed out/added 5 diplexers


    lots of places for a gremlin to hide.
    the 23's may just flat out have a lower RF threshold, 'leaky' diplexer, noisy line, RF interference from an outside source, one of the diplexers is eating the control frequency, bad port on the splitter that wasn't in use previously.....


    If i'm totally off base here, at least it will be one hell of a learning experience.
     
  9. Oct 7, 2009 #9 of 49
    Non Jeff

    Non Jeff AllStar

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    Actually the number of diplexers used has dropped from 3 to 2 (not counting diplexers at the boxes).

    I removed the three H10's from the legacy ports, which are now completely empty. Subtract three diplexers.

    I removed two H20's from the SWS-8 connected to the SWM-8.

    I put those two H20's on the paralleled WB68 multiswitch. From the multiswitch, I added the BBC's to the ports, and connected them to a diplexer to join OTA signal, and from there to the H20's. Add two diplexers.

    Thus I had four tuners using the SWM-8 (HR20 and two H23's). I added the three new H23's to the SWM-8 for a total of 7 tuners total. No diplexers added.

    Only one new connection to the SMW-8, which was on the legacy port (the other two legacy ports went to the paralled WB68).

    So in summary, I'm actually using one less diplexer, and only added one new run from the SMW-8. But your point is well taken - there are so many places that could be causing the interference, and I've wondered about a bad port on my splitter, too. Thanks for your thoughts - anything is appreciated.
     
  10. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "One thing" is that the diplexers at each receiver are trying to send the 2.3 MHz comm signal through a port [with filtering] that is for 950 MHz and above. This means there is a lot of loss in this signal.
     
  11. HoTat2

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    That's what I suspect, assuming the DC power pass going through the satellite leg of the diplexer is totally filtered for RF, the 2.3 MHz control signal for the SWM-8 module is trying to communicate upstream from the receivers through an RF port filtered to accept 950-2150 MHz.

    Are the receivers which keep randomly losing the satellite signal when OTA is diplexed in the ones connected to the SWM-8?
     
  12. David MacLeod

    David MacLeod New Member

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    would a diplexer hooked up wrong (swapped terminals) cause this? I've never thought to ask before.
     
  13. Non Jeff

    Non Jeff AllStar

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    Yes, the receivers losing signal are only those using the SWM-8. And they have problems randomly. One day it will be two or three receivers, the next day it will be a different 2 or 3. The receivers using the WB68 (and diplexed) are fine.

    So basically the comm signal for the SWM-8 is being filtered out by the diplexer? (2.3 MHz will not pass through the 950-2250 MHz range of the satellite arm of the diplexer?) If so, that makes sense, but wonder why others haven't had similar trouble diplexing.... seems like no diplexing would work if that is the case, yet we know many have done so.

    Is the fact that I consistently lose even polarity on satellites significant? After you choose your sat dish and multiswitch in the H23, it "verifies" your choices by testing it, and brings up the results. I consistently see errors on the even polarity for 99 and 103c, and it reports an error on tuner 1. I read grounding issues can affect polarity, yet it should bother all receivers I would think. Also, weakness.com talks about getting a "polarity locker" that may be needed between the 5LNB and high-freq splitters - could this be what is needed?

    Thanks to everyone for their brain and thoughts....
     
  14. houskamp

    houskamp Active Member

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    also possible that extra "junk" is coming down the OTA.. try running it without the OTA connected to input of diplexors.. this will tell you if it's the ota or the connections..
     
  15. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    The SWM8 IS a polarity locker, since it's powering the LNBs [through the four cables].
     
  16. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    You may have a point here since "it seems" if the OTA input is removed, the problem goes away.
    Adding a filter [blocking below 50 MHz] might help.
     
  17. eakes

    eakes Godfather

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    Since the "problem" seems to randomly move from receiver to receiver and goes away when the antenna lead is removed, I would suspect there is extraneous signals being picked up by the antenna and being fed into the system that is causing interference with the signal channels from the SWM. As the actual SWM channel used to deliver signal to a particular receiver will change from time to time, the "problem" will travel with the channel(s) being interfered with, thus the "problem" seems to randomly effect different receivers.

    One could use an RF spectrum analyzer and look at the coax at one or more receivers and actually see which channel(s) are being effected. One could then apply a filter in the antenna connection to minimize the interference - maybe!

    I believe I read that there was a preamp on the antenna. What is the situation if the preamp is removed and the un-amped antenna connected?
     
  18. houskamp

    houskamp Active Member

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    also try FM traps.. that was what was killing mine (local FM station)
     
  19. Non Jeff

    Non Jeff AllStar

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    Yes I have a pre-amp (25 dB) at the antenna in the attic of my garage feeding down to my basement utility room where my cable distribution center is located. The OTA run is probably a good 100 feet, and its best to amplify the pure signals. Then there is a second pre-amp (10 dB) right before my OTA 8-way splitter located at the distribution center. All my ATSC tuners in my HDTV's and the H20's pick up my locals in my secondary market (60 miles away) at near 100% strength using a DB4 antenna, and oddly the locals for my city (which are strangely located 30 miles away) only come in at 75% because I must use a smaller UHF antenna for those. I can't use the FM Trap for some reason, as it creates interference on analog (well, back when I had to use analog), but also affects digital signals as well. Not using the FM trap does have its advantages, as I get great FM reception through the coaxial.

    This is exactly what I was thinking - something in that OTA line is garbage, and leaking into my sat signals. It is definitely not a specific H23 since it has occurred in all boxes at somepoint. Perhaps I'll fiddle with the FM trap since others have had problems with it. Its been a long time since I monkeyed with that. Good idea, thx.

    I am going to try something - I will disconnect the OTA and setup all the receivers without OTA, one at a time. AFTER that, I will then reconnect OTA diplexing and see what happens. It occurred to me that I have always set up the boxes while OTA was being diplexed, and today re-read a trouble shooting article posted here which gave steps to try to figure out if the problem was a faulty SWM or a receiver. One of those steps was to do a "clean" setup, so I will try this. Should have done this in the first place actually....

    I have checked my ground and its solid. All my cable is high quality as are my splitters and diplexers and compression connectors, and its always worked without any apparent RF interference. If some new signal garbage contaminant from the OTA signal has entered the picture, I don't think I would be able to trace it. But I'm feeling fairly certain that the system is "shielded" as best as possible.

    Regarding these so-called polarity lockers - first, they're very expensive; second, it said it would rarely be needed in a residential setting since it might be necessary for very long runs between the dish and splitters, thus its more for MDU. VOS mentioned the SMW IS a polarity locker, and that's exactly what my uneducated sense told me based on the 13V and 18V inputs on the SWM8. My run between dish and splitter is only about 20-25 feet. So scrap that idea.

    k, off to hack off my family again by forbidding any TV watching once again while I test my system. My daughter just asked, "Dad, why don't you just call someone...." - she just doesn't understand its now become a mission. Besides, I don't think my local installers are familiar enough with SWM setups. I will post my results....

    Thanks to everyone for helping, it is much appreciated.
     
  20. RobertE

    RobertE New Member

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    Calling someone isn't going to do anything for you. DirecTv policy will be to remove all the diplexers.
     

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