[linux-dvb] Re : Re : No lock possible at some DVB-S2 channels with TT S2-3200/linux

Dominik Kuhlen dkuhlen at gmx.net
Sat Jun 21 14:36:47 CEST 2008


> >
> > Could you please try the attached patch if this fixes the problem with
> > nominal frequency/symbolrate settings?
> >
> Many thanks, but I don't see any improvement. Minimum time after I've lock is 
> 150s. 
Could you please check whether the reported frequency is sane:
Example: 19.2°E 11915MHz H 27500 DVB-S2

Test1: use the nominal frequency:
 ./simpledvbtune -f 11915 -d 2
dvbfe setparams :  delsys=4 1315.000MHz / Rate : 27500kSPS
Status: 1b: Signal Carrier Sync Lock
SNR: 0 44 (0x2c) (4.4dB)
BER: 0 0 0 0 (0x0)
Signal: 5 170 (0x5aa) 1450 (145.0dBm)
Frontend: if=1313.627 MHz

Test2: set positive offset (+3MHz):
./simpledvbtune -f 11918 -d 2
dvbfe setparams :  delsys=4 1318.000MHz / Rate : 27500kSPS
Frontend: if=1313.660 MHz
The frontend does automatically locks on the correct frequency

Test3: set negative offset (-4MHz):
./simpledvbtune -f 11911 -d 2
dvbfe setparams :  delsys=4 1311.000MHz / Rate : 27500kSPS
Frontend: if=1313.650 MHz

Find lower limit:
./simpledvbtune -f 11896 -d 2  (does not work)
./simpledvbtune -f 11897 -d 2 (works 100%)
dvbfe setparams :  delsys=4 1297.000MHz / Rate : 27500kSPS
Frontend: if=1313.654 MHz

Find upper limit:
./simpledvbtune -f 11930 -d 2 (does not work)
./simpledvbtune -f 11929 -d 2 (works 100%)
dvbfe setparams :  delsys=4 1329.000MHz / Rate : 27500kSPS
Frontend: if=1313.645 MHz

Which means:
 - I can specify any frequency from 11896MHz to 11929MHz and get 100% lock success
 - and the Frontend (actually the derotator) reports the real frequency (e.g. for auto correcting the channels list)

Cards I have tested so far: 
- pctv452e 
- mantis (Multimedia controller [0480]: Twinhan Technology Co. Ltd Mantis DTV PCI Bridge Controller [Ver 1.0] [1822:4e35] (rev 01)
               Subsystem: Twinhan Technology Co. Ltd Unknown device [1822:0031])

Unfortunately I'm trapped behind a single-cable installation and have only access to 19.2°E Highband Horizontal


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