[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 18:40:46 CEST 2008


I managed to get access to a 19.2 + 13.0 diseqc dish with a TT-S2 3600 card :)

On Saturday 21 June 2008, Ales Jurik wrote:
> Hi,
> on the frequency you've mentioned I didn't have any problem (never). But at 
> lyngsat it is reported as 11914MHz. I never used freq. shifting (only 
> tested), it was not reasonable for me.
I wanted to show that there's no reason for setting all frequencies +4Mhz or -4MHz.
This is what my patch is all about :)
The request for test tuning with a offset was to confirm the "bug" i found 
in the stb0899 tuning routine

> Problems I have are at transponders with 8PSK modulation. 
Well, I tested: 
19.2 12522 V 8PSK 22000 2/3
  i get 100% (and immediate) lock in the range from: 12512 to 12532
(The frontend always reports 1921MHz (i.e. 12521MHz))
the call looks like:
./simpledvbtune -f 12512 -p v -s 22000 -d 2  -a 1
using '/dev/dvb/adapter1/frontend0' as frontend
frontend fd=3: type=0
ioclt: FE_SET_VOLTAGE : 0
High band
tone: 1
dvbfe setparams :  delsys=4 1912.000MHz / Rate : 22000kSPS
Status: 1b: Signal Carrier Sync Lock
SNR: 0 22 (0x16) (2.2dB)
BER: 0 0 0 0 (0x0)
Signal: 5 170 (0x5aa) 1450 (145.0dBm)
Frontend: if=1921.821 MHz

19.2 12581 V 8PSK 22000 2/3
 works  in the range from 12570 to 12590
frontend reports: 1980 (i.e.12580)

13.0 11996 V 8PSK 27500 2/3
 works from 11986 to 12005
frontend reports: 1395 (i.e. 11995)

The other 13.0 8PSK (11278V and 11449H) are tougher:  they take a few seconds to lock and sometimes they don't lock at all
according to the NIT they use roll-off factor 0.2 (the other channels use 0.35)
This is interesting: I'll check why this takes so much longer


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