Problem in UK Com 7 / 8 Freeview (1 Viewer)

alister

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  • May 11, 2010
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    I can't tune the TBS 6281SE in my Media PC nor my Parents TBS-6205 to either (two seperate houses)

    746000 or 75400 on Durris @14.5kW vs 50/100 kW for other muxes

    TVs on same aerial pick these up no issue (hence rule out aerial) 169 channels found

    all regions scan results

    Total radio 29
    Total TV 94

    46 missing TV/Radio are Com 7 / 8

    I'm guessing the cards aren't picking up the mux for some reason. Too low ? I'm 18km from the mast
     

    CyberSimian

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  • June 10, 2013
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    746000 or 75400 on Durris @14.5kW vs 50/100 kW for other muxes
    This is probably a signal-strength issue.

    Tuners in HTPCs tend to have lower sensitivity than those in TVs, and as a result require a higher signal level in order to receive the lower-power MUXes. My impression is that the TBS tuners are better than average in this respect. Example: my TBS 6284 tuners can receive more MUXes than my Pinnacle 2000i tuners (both tuner cards are in the same HTPC and fed by the same aerial).

    The COM7 and COM8 MUXes are the most difficult to receive, as they are very low power, and they are at the top end of the UHF range, where propagation is worse. In fact I gave up trying to receive them at my location (Rowridge transmitter).

    If you really want to receive COM7 and COM8:

    (1) Install a bigger aerial outside the house.
    (2) Ensure that it is correctly aligned.
    (3) Consider receiving from alternative transmitters in your area.
    (3) Consider using a masthead amplifier.
    (4) Use satellite-grade aerial downlead.

    You can use an aerial amplifier next to the HTPC, but although it increases the signal level, it does not improve the signal quality (in fact it worsens the signal/noise ratio), so this may not provide any improvement.

    -- from CyberSimian in the UK
     

    alister

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    (1) Install a bigger aerial outside the house.

    Got the biggest possible already

    (2) Ensure that it is correctly aligned.

    Shooting through a gap in between houses

    (3) Consider receiving from alternative transmitters in your area.

    There is ONLY Durris

    (3) Consider using a masthead amplifier.

    I'll think about this

    (4) Use satellite-grade aerial downlead.

    Done already
     

    Owlsroost

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  • October 28, 2008
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    You could try increasing the 'Tune' timeout in the TV Serve Configuration -> General tab -> Scan tab - see: General Configuration

    Default is 2 seconds - maybe try 5 seconds?

    What is the reported signal strength/quality like on the other muxes? (It's reported in TVService.log in C:\ProgramData\Team MediaPortal\MediaPortal TV Server\log)

    Code:
    [2018-12-19 16:10:15,859] [Log    ] [23       ] [DEBUG] - card: Tuner locked: True
    [2018-12-19 16:10:15,864] [Log    ] [23       ] [INFO ] - **************************************************
    [2018-12-19 16:10:15,868] [Log    ] [23       ] [INFO ] - ***** SIGNAL LEVEL: 64, SIGNAL QUALITY: 61 *****
    [2018-12-19 16:10:15,872] [Log    ] [23       ] [INFO ] - **************************************************
     

    CyberSimian

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  • June 10, 2013
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    The COM7 and COM8 MUXes changed frequency last year, so if you were using MP's Durris tuning file from an older release of MP, it is possible that you were scanning the old frequencies for COM7 and COM8, and not the new frequencies. However, I note that in your first post you stated all regions scan results. If you did indeed scan all frequencies, you would have found COM7 and COM8, if they were receivable.

    One way to eliminate MP as the culprit would be to install some other media center software or DVR software, to see if they can receive COM7 and COM8. If they can, it indicates a problem with MP. If they cannot, it indicates that the signal is too weak for your HTPC tuners. Note: you must disable MP's "TV Service" before installing other software, in order to allow the other software to access the tuners.

    If you search for "media center software" or "dvr software", you will find a selection of softwares available, some of which are free.

    -- from CyberSimian in the UK
     

    alister

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  • May 11, 2010
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    One way to eliminate MP as the culprit would be to install some other media center software or DVR software, to see if they can receive COM7 and COM8. If they can, it indicates a problem with MP. If they cannot, it indicates that the signal is too weak for your HTPC tuners

    Signal level on other mux



    I've tried other software and can't tune

    Durris is Scheduled to need a Group T aerial, I think I've got a wideband up there - should work though?

    I'm running a scan with timeout set on 5 secs rather than 2 secs



    482000 Scan: tuner locked:True signal:85 quality 49 100kW
    490000 Scan: tuner locked:True signal:83 quality 49 50kW
    506000 Scan: tuner locked:True signal:83 quality 49 100 kW
    514000 Scan: tuner locked:True signal:83 quality 49 50kW
    530000 Scan: tuner locked:True signal:84 Quality 49 100kW
    546000 Scan: tuner locked:True signal:84 quality:49 50kW

    Looks like the strength is OK just the quality is 49 is that low? (I'm using sat cable and F connectors, the splitter is a metal F connector one)

    I'll check the Parents (which is at my parents) and see what the results are
     

    Owlsroost

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    Attached is latest MP TV Server 'tuning parameter' file for the Durris transmitter - put it in C:\ProgramData\Team MediaPortal\MediaPortal TV Server\TuningParameters\dvbt

    Then try a channel scan of just Durris (to keep the logs sensible) - if it tunes com7/8 OK then fine, otherwise zip up the TV Server logs (from C:\ProgramData\Team MediaPortal\MediaPortal TV Server\log) and attach them here.

    This what's in the tuning parameters file - so it definitely has the current com7 & com8 muxes covered:

    Code:
    <?xml version="1.0" encoding="utf-8"?>
    <ArrayOfDVBTTuning xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
      <!-- PSB1 -->
      <DVBTTuning>
        <Frequency>530000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- PSB2 -->
      <DVBTTuning>
        <Frequency>506000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- PSB3 -->
      <DVBTTuning>
        <Frequency>482000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- COM4 -->
      <DVBTTuning>
        <Frequency>490000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- COM5 -->
      <DVBTTuning>
        <Frequency>514000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- COM6 -->
      <DVBTTuning>
        <Frequency>546000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- COM7 -->
      <DVBTTuning>
        <Frequency>746000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- COM8 -->
      <DVBTTuning>
        <Frequency>754000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
      <!-- LOC1 -->
      <DVBTTuning>
        <Frequency>634000</Frequency>
        <BandWidth>8</BandWidth>
        <Offset>167</Offset>
      </DVBTTuning>
    </ArrayOfDVBTTuning>
     

    Attachments

    • UK.Durris.xml
      1.4 KB

    Owlsroost

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    These are the scan results (parser out of TVService.log):

    Code:
    [2019-01-12 21:17:02,330] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:530000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:17:02,433] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:87 quality:49
    
    [2019-01-12 21:17:11,057] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:506000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:17:11,495] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:83 quality:49
    
    [2019-01-12 21:17:16,843] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:482000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:17:17,417] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:84 quality:49
    
    [2019-01-12 21:17:27,085] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:490000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:17:27,525] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:84 quality:49
    
    [2019-01-12 21:17:33,143] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:514000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:17:33,578] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:83 quality:49
    
    [2019-01-12 21:17:39,104] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:546000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:17:39,547] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:85 quality:49
    
    [2019-01-12 21:17:45,185] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:746000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:17:46,454] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:75 quality:0
    
    [2019-01-12 21:18:49,161] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:754000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:18:50,430] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:100 quality:0
    
    [2019-01-12 21:19:53,120] [Log    ] [9        ] [INFO ] - dvbt: Scan:DVBT:tv:  Freq:634000 ONID:-1 TSID:-1 SID:-1 PMT:0xFFFFFFFF FTA:False LCN:10000 BandWidth:8
    [2019-01-12 21:19:54,401] [Log    ] [9        ] [INFO ] - Scan: tuner locked:True signal:100 quality:0

    Note the 'quality:0' for the 746000, 754000 and 634000 kHz frequencies (com7, com8 and loc1 muxes).

    So basically, for those frequencies, the tuner is saying it's locked on to the frequency, but the digital stream is rubbish... (the 'locked' 'signal' and 'quality' info comes from the tuner drivers, as far as I know).

    That said, the 'signal:100' for those frequencies seems suspicious - could there be interference from something in the PC maybe (which the tuner is picking up instead of the real off-air signal)?
     
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