No channels on V polarity

Discussion in 'Free To Air (FTA) Discussion' started by flighttothemoon, Sep 19, 2010.

  1. flighttothemoon

    flighttothemoon Thread Starter Member

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    Hi all. The reason why I am asking for help on the forum is a problem with sat dish setup that I have had for the last month. Half a year before it, It had been working fine. But a month back one day I could not find around half of channels. Trying to scan again, I noticed that I cannot find channels of V polarity. Only H.
    I am using tv tuner Technisat Skystar HD 2 PCI in my PC and circular LNB. Software - DVBViewer Pro.
    By now I have tried as follows:
    - Tried to install the tuner into other computer. No result.
    - Returned the tuner to shop and got a new one. No result.
    - Changed LNB to a new one. No result.
    - Checked voltage from the both tuners (the old returned one and the new one). It changes from 13 to 18 and back.
    - Checked voltage on the end of cable going from the tuner to LNB. Voltage changes.


    What else can be a problem? I do not understand. Any help appreciated.
     
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  2. Mikhel

    Mikhel On Vacation

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    Get another receiver and check that, if it fails to get the "H" channels, then you might as well have a defective LNB or a bad cable run... altough using a circular LNB there is not much, if any, that can be received.

    Cheers

    Mike
     
    #2
  3. flighttothemoon

    flighttothemoon Thread Starter Member

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    Another reciever? As i wrote, I returned old reviever to store and got a brand-new one but the problem still exists. The same about LNB. Tried two LNBs.
     
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  4. Mikhel

    Mikhel On Vacation

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    Yup another receiver (a STB), to discard anything related to the DVB card.
     
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  5. delta_charlie

    delta_charlie Active SatelliteGuys Member

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    Hi Flighttothemoon, are you located in Russia? What satellite are you trying to receive?

    FYI - a circler LNB will not pick up H or V polarity very well, it should only be used on a satellite with circler L or R polarity.

    How did you test the voltage at the LNB? I think you might have a bad cable run that is loosing voltage under load. Maybe try using a barrel connector at the LNB and add a short piece of coax with a slot cut in the side so you can test with the LNB hooked up.

    Hope this helps, DC
     
    #5
  6. flighttothemoon

    flighttothemoon Thread Starter Member

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    Hi. Yes, located in central Russia and trying to recieve Eutelsat W7 36E.
    As to cable, using digital meter, I tested voltage straight from tuner and from the end of cable that goes from tuner, before it goes to LNB. In both cases, voltage changes 13/18. Can it still be the problem in cable if voltage is ok?
     
    #6
    Last edited: Sep 20, 2010
  7. Elchucko

    Elchucko Member

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    I noticed on Lyngsat that the R polarity are DVB-S2 but the L polarity are only DVB-S.

    Is your card capable of receiving DVB-S2?
     
    #7
  8. flighttothemoon

    flighttothemoon Thread Starter Member

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    Yes, it is. My card is Technisat Skystar HD2 PCI TechniSat SkyStar HD 2 with RC set (Export) [4102/3734]
    Like I wrote in the first message, it worked fine for half a year, receiving both DVB-S and DVB-S2 channels.
    I suspect the problem is cable, as i have already tried 2 receivers on different computers, tried two circular LNBs. Is there any way to check cable before replacing it? Because it goes from roof and it is quite complicated to wire it all over again. Would not like to do it in vain.
     
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  9. thebaggins

    thebaggins Member
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    How about checking the connections first, any small amount of oxidation could be causing problems.
     
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  10. flighttothemoon

    flighttothemoon Thread Starter Member

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    How to check it?
     
    #10
  11. turbosat

    turbosat SatelliteGuys Family

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    Unscrew and look at the connector ends............look for obvious signs of water intrusion like rust, discoloration. Check the center conductor , broken,, or too short to connect properly.
     
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  12. delta_charlie

    delta_charlie Active SatelliteGuys Member

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    Hi Flighttothemoon, yes the cable or more likely a connector could have corrosion and this can cause a loss of voltage but only when under load. A digital volt meter is so sensitive it will show voltage on an open cable but when a load is applied the voltage can drop to nothing. That's why I suggested using a barrow connector and a short piece of coax with a slot cut in it so you can test the voltage at the LNB to see if it holds under load. If it is dropping try checking near the receiver to verify the voltage is holding there. This should let you know if the cable/connectors are the problem or if it is something else.

    Let us know if you figure it out, DC
     
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  13. flighttothemoon

    flighttothemoon Thread Starter Member

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    The cable was the problem, indeed. Tried a new cable and could receive all other channels.
     
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  14. flighttothemoon

    flighttothemoon Thread Starter Member

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    Okay, early to be happy. Received V-polarity channels but the strange thing is they do not work. I click on them but no picture comes out.
     
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  15. Kallesatman

    Kallesatman Member

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    For what it is worth; try rescanning the satellite now that you've replaced the cable. It can only help.
     
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  16. flighttothemoon

    flighttothemoon Thread Starter Member

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    Rescanned many times. Able to receive more channels, not all V-polarity channels though, not as before. And picture on these received V polarity channels is either absent or tearing, whereas picture on H-polarity ones is perfect. Very weird.
    I also tried to check reception with portable satfinder connected between LNB and receiver. So, reception is good but sometimes 22 khz lamp on blows out for a second and beeping signal weakens. What could it mean?
     
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  17. Kallesatman

    Kallesatman Member

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  18. AcWxRadar

    AcWxRadar SatelliteGuys Family
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    Flighttothemoon,

    Since you have already found some trouble with your cable, could it be that there is still a cable or connector problem? I would rule this out first by taking your components as close as possible to your dish and running the absolute shortest cable you can possibly use with exceptional connectors and connections that are made well.

    If you achieve the same results after doing this as you are when using your current cable run, then you can at least rule that out as a possibility and work on the other possibilities.

    I know that it won't be an easy task to do this since you are using a PCI card with your PC, so it won't be as simple as just hauling a STB and a portable TV out there, but I highly urge you to try it if the weather works with you.

    Judging from the fact that your system operated well previously, and since you have already ruled out any defect with the PCI card and the LNBF, then that leaves me to question the cable and the dish alignment. Rule out the cable first, then check your dish alignment to ensure that it didn't get moved in any way or that your LOS didn't get blocked by a tree limb that has been growing slowly over time, etc.

    Also, I am not certain if you mentioned it or not, but do you have any external switches in use here? If you do, remove them entirely and run a straight cable between the PCI and the LNBF and test that way to rule out any possible defects there. I didn't think you had any switches, but included this idea just in case.

    I reread your last post here and now I am leaning towards the dish alignment and/or some obstruction in your LOS - based upon your report of how the signal meter responded. Maybe a weakened signal is not welcomed by your PCI card.

    Wishing you luck in isolating the trouble and repairing it!

    RADAR

    P.S. Welcome to SatelliteGuys forum! Great to have you join us! :)
     
    #18
  19. flighttothemoon

    flighttothemoon Thread Starter Member

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    Thank you all for trying to help me. It looks like the reason of the problem is quite simple - dish alignment (maybe it moved because of strong wind at night), as i changed card, LNBF, cable, and I dont have a switch. What I have now is almost all channels as before, but picture of V (only V. H-ones work great) -polarity ones (in Dvbviewer I have H- and V-ones) is kind of broken. Am i right? Alignment?
     
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  20. thebaggins

    thebaggins Member
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    I've had that happen before H polarity fine but V polarity had either weaker (lower) quality or jumping numbers, my fix was to bump dish east or west to max out V polarity and monitor H to make sure I didn't go to far
     
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