Skystar USB HD + VDR + Astra 23.5E 11817 V / 8psk,fec=5/6

  • Since recently I have been using Skystar USB HD with my vdr box. However I have some strange issues with 11817V on Astra 23.5E. Femon reports that there is a lock and sound comes but the image is completely garbled. I am starting to suspect that there might be something wrong with the driver, because I have no trouble with the other transpoders. Maybe it is the combination of fec=5/6 and 8psk on the said transponder that is the reason for this. Other transponders with fec=3/4 and 8psk are OK. The same setup with an HVR-4000 works fine.
    Kernel: 3.3.4
    VDR: 1.7.27
    Could someone who owns a Skystar USB HD and has access to Astra 23.5E share his experience? Is this a driver issue or is my card faulty?
    If someone would be kind enough to test this with his/hers hardware, there is a FTA channel on the problematic transponder:


    Planeta HD;SatelliteBG:11817:VC56M5O35S1:S23.5E:27500:1001=27:1002=@3:0:0:5410:3:3206:0


    Any help would be greatly appreciated.

  • Hi,


    You will IMHO not find a lot of users here that have an LNB pointing at Astra 23.5. I did a quick check on S19.2E if there is a transponder with the same parameters (*C56M5O35S1), but I couldn't find one. Maybe there is one on Hotbird? If you could reproduce your problem on S19.2E you will find loads of people here that might be able to test.


    According to kingofsat there is only one FTA channel on that transponder. The users here will most likely only be able to receive that FTA channel, not the encrypted channels.


    Cheers,
    hepi

  • Hi,


    I also checked and unfortunately there is no transponder with the same parameters on Astra 19.2e. On Hotbird there is 11411H, which is HC56M5O35S1 but I don't have acces to it.

  • I found the time yesterday and tested 11411H on Hotbird. The result was the same. Obviously it is not a problem with vdr, bacause this time I used dvbsnoop to see if something was wrong and it definitely was, Both with 11411H on Hotbird and 11817V on Astra 23.5E.



    Out of all the transponders that I tested these were the only that produced such errors. What they have in common is the 8psk modulation and code rate of 5/6. Also they are high bitrate (~66Mbps) but that may be irrelevant as there are 8psk 3/4 transponder with comparable bitrate which are OK.
    I have already written to the linux-media mailing list, but it would be really nice if someone else could verify this to rule out the possibility of a faulty hardware.


    BTW, if it is a driver bug it could possibly affect other hardware using the stv090x module.

  • I haven't used Windows at home for years, so I can't test. The bug report you linked is about high symbol rate (30 000). The symbol rate of the problematic transponders is 27500. SR 30000 is available on a couple of transponders on Thor 1W but their fec is 3/4, so probably they would be OK. And also the transponders on Hotbird which have a symbol rate of 29900 work fine. Those are also with a total bitrate of ~65Mbps. IMHO this rules out the possibility that high symbol rates or bitrates are the source of the issue. More likely there is something wrong with the way 8psk in conjunction with fec 5/6 i s handled by the driver.

  • OK, I see.


    In those situations it might be handy to have Windows (on a laptop) if it allows to quickly prove that it is a Linux driver issue. I myself have a laptop also running Windows but never used it to test the USB DVB devices I own until now... ;-)


    Cheers,
    hepi