Db and BER readings compared to signal quality

Discussion in 'Free To Air (FTA) Discussion' started by SkySurfer80, Aug 15, 2019.

  1. SkySurfer80

    SkySurfer80 Topic Starter SatelliteGuys Pro

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    Well after buying a Satlink meter It has a db and BER readout. The signal qualitt readout on it is pretty useless as it is always between 60 to 69 on all locked transponders. I never paid attention to db and ber but am learning by using this meter and have to say it is very helpful. After unwarping my 90cm and using this meter and its db and ber readouts I have totally locked in my dish to what I believe is the best quality I can get.

    I am trying to figure out a conversion of signal quality to db ratio but not sure it would be accurate so I am still learning.

    For instance on the newsource on 87 west I am hitting at a 89 quality and a 14.5 or so db, however on the NY lotto feed "Adtec2" I am hitting at 30 pct quality and a 10.2 db. Then on 91 News channel mux I am hitting at 81 pct quality and a 13.6 db. So I am curious how the receivers come up with quality and it seems like you just cant max out all tps to high 80s or 90s.

    Any of you have any light to shed on this info about Db or BER?
     
  2. Titanium

    Titanium AI6US Lifetime Supporter

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    SNR (Signal to Noise Ratio) is expressed in db. The higher the dB reading, the higher the signal carrier strength compared to the noise floor. A receiver will require a minimum SNR to lock. The modulation type and FEC (Forward Error Correction) ratio determines the minimum SNR reading. For example, a 16PSK or high FEC (9/10, etc.) Will require a higher level of signal vs noise to reliably lock onto the carrier.

    BER (Bit Error Rate) is the percentage of bit errors received in a transmission measured over a time period. The reading is displayed as ten to a negative power. The lower the BER value reading, the less amount of error correction is required resulting in higher quality transport stream decoding.

    The optimal signal reading is a high SNR dB reading and low BER reading.
     
  3. Brct203

    Brct203 SatelliteGuys Pro

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    the problem is that SNR is a science, but Signal Quality should be one too, with a clear equivalence to SNR reading, but instead it seems that each manufacturer, and even each receiver, has its own scale... so a SQ reading makes some sense only in comparison to other readings on the same receiver.

    Otherwise we would all be using Linkbox 9000 receivers right now :)
     
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  4. comfortably_numb

    comfortably_numb Dogs have owners, cats have staff Pub Member / Supporter

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    The Edision OS MIO 4K displays signal quality as SNR, measured in dB...
     
  5. Brct203

    Brct203 SatelliteGuys Pro

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    yes and I love it!

    It can be switched to %, but I much prefer it to be displayed in dB. Some skins even display in BIG fonts (when in Signal Finder) so that you can reasonably well read it while adjusting the dish, if you have the display not far from the dish. Really nice!
     
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  6. comfortably_numb

    comfortably_numb Dogs have owners, cats have staff Pub Member / Supporter

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    screenshot_20190815155046.jpg
     
  7. SkySurfer80

    SkySurfer80 Topic Starter SatelliteGuys Pro

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    I do get some tps at a 14 plus db. Some though can be 13 plus db but be 60 pct quality on my geosat hdvr but others at a 14 or so db and show 90 pct! So the ratio is off as far as percentages go. I am hitting the PBS mux around 13.5 db yet the quality is 65%.
     

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