Why is Linux dvb signal so bad when compared with Windows ?

    I've been using a Geniatech HDSTAR dvb-s2 usb receiver (self powered) in my Raspberry Pi 4 running LibreELEC.

    recognised by dmesg as SU3000HD DVB-S USB2.0 //: Montage Technology DS3000/TS2020

    firmware: dvb-fe-ds3103.fw


    The reception has not been the best one on LibreELEC.

    I've connected the same receiver to a Windows PC, and the signal and reception improved considerably !

    My tests were with:

    - raspberry pi4, libreelec: DVBLINK and TVHEADEND

    - Windows 10: DVBLINK and SMARTDVB

    using the same receiver.

    Examples:

    A transpoder with 10% signal in LibreELEC on the Pi has like 55% signal in windows.

    A transpoder with 30% signal in LibreELEC (pi4) has 80% signal in windows.

    In the end, I can watch channels in windows with top quality, that are impossible to lock in linux.

    As if windows driver has some way of enable some sort of "amplifier" in the driver.

    Is there way of adjusting the "power" in the linux dvb driver ?

    Or an update to the linux driver that is not included in LibreELEC dvb drivers ?

    This problem happens with all LibreELEC module drivers (crazycat, and "latest" included with 9.2.3. Standard drivers do not support this receiver)


    I've attached a link to my dmesg in LibreELEC.

    I have also a running dvb-c receiver from silicon labs. Please ignore it.

    Only consider the dvb-s2 receiver.

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    Hello!

    On windows your using x86 drivers and a PC or Laptop compared to LInux and Rpi4.

    Have you tried x86 with Linux/LE?

    Have you tried a powered USB Hub in the Pi to Power the Tuner?

    Worth a Test to Tracks the Problem down.

    Regards

    Nicolas

    Hi. Thank you for your suggestions.

    Besides the receiver being self powered, I connect every USB devices to the Pi4 trough a powered USB HUB (which in turn has a 5V @ 4A PSU) in order to make sure that no issue comes from power issues.

    I've also tried the same testing with a Pi 3 running OSMC without any other usb device connected, just to be sure.

    All tests with a raspberry pi official PSU.

    Okay...

    Maybe worth a try to Put LE generic on a USB Stick and try it in your Windows PC.

    Just to se If there is a difference betwen the Linux and the Windows Driver in the Same Hardware.

    Regards

    Nicolas

    I've just made as suggested, but no luck:

    A new sdcard with LE for x86 booting in my PC.

    Only Crazycats drivers recognise the device.

    But the tuning is very bad.

    A transponder that locks and plays perfectly when running within windows (with windows drivers, of course), cannot be locked when running in LE.

    In an entire sat, only 2 transponders are locked by LE.

    In the same sat, running in windows, there are tons of transponders and channels locked.

    One could assume there is a linudvb driver issue (related to signal amplification ?).

    At least for this device.

    Please look at the dmesg above.

    Bellow is the dmesg from LE in x86, with crazycats drivers:

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    Quote from nvdias

    Hi. thanks for your comment.

    And there is no plans to update it ?


    Any cheap usb receiver recommended for best results in Linux ?

    IMHO cheap with best results is Not possible. Since Kernel 4.19 I don't have tried USB Tuners with the RPI. Suntech, dvbsky 960 all Had issues but were running fine in x86 Hardware.

    I prefer using PCIe DVB-S Tuner or a sat-ip solution Like the Kathrein exip 418, digibit r1 or digibit twin, xoro sat-ip Server 8100 in combination with Tvheadend.

    Regards

    Nicolas

    I've downloaded you last media drivers and compiled them in osmc to test for different results.

    But I'm getting the same low signal strength

    Will it be a linux firmware issue for this device ?

    thanks

    crazycat ,

    After all, I was not compiling your last version, but one I had in my disk.

    Now I've updated form your new gitsource GitHub - crazycat69/media_build

    But now, the device cannot tune-in anymore !

    The device which had the name in tvheadend as "Montage Technology DS3000/TS2020",

    was now recognisable as "Montage Technology M88DS3103B", but incapable to tune in anything !

    Reverting back to the old drivers, I was able to tune in, but with the old low signal issue.

    Even with this low signal issue, is it possible to at least guarantee that the device is still supported (this, thinking in the future)?

    Thanks.

    Edited 3 times, last by nvdias (August 14, 2020 at 5:25 PM).

    Quote from crazycat

    Don't worry about legacy signal strength/quality in %. Usual this calculated in different way depend from developers :)

    ok. thanks. But I'm not much worried with that.

    But i am worried that with the new drivers, the device cannot tune any channels.

    And that could mean it will stop working with libreelec in a near future...

    Is it possible to confirm that the new drivers are still compatible with it ?