Oliver Endriss wrote: > Luc Brosens wrote: >> Hi, >> >> side note : >> the problems in my previous post "KNC1 TV-Station S, revision 0x1894, doesn't tune", were related to the PCI-slots of the motherboard I used >> rebuilt the machine around a new motherboard, both KNC1's are now recognized and able to tune >> lesson learnt : check the hardware before complaining about the software ... > > Hm. > >> why does inserting and accessing a CAM reduce the signal and SNR levels ? (even if no descrambling is needed, as for BBC World) >> how can this be solved ? >> anyone out there having the same problems ? > > I guess that the CAM increases the noise on the power supply planes of > the card. This might affect the tuner. ;-( > > CU > Oliver > so I changed gnutv to only initialise the CAM after obtaining FE_HAS_LOCK apparantly, initialising the CAM is enough to loose the tuning lock, not to return afterwards so this is not a solution here's a run with femon monitoring the tuning status : I start of with the CAM in the slot, and try to gnutv-tune to BBC World (which is not scrambled, so need for the CAM) mythtv@silverstar:~/dvb-apps> femon -a 1 -H FE: ST STV0299 DVB-S (DVBS) status S | signal 63% | snr 49% | ber 14077 | unc 0 | status S | signal 79% | snr 51% | ber 13311 | unc 0 | status S | signal 69% | snr 50% | ber 13776 | unc 0 | status S | signal 82% | snr 52% | ber 13583 | unc 0 | status S | signal 62% | snr 49% | ber 13375 | unc 0 | status S | signal 79% | snr 53% | ber 13563 | unc 0 | status S | signal 80% | snr 49% | ber 13387 | unc 0 | status S | signal 71% | snr 52% | ber 13524 | unc 0 | status S | signal 63% | snr 49% | ber 13565 | unc 0 | status S | signal 81% | snr 52% | ber 13125 | unc 0 | status S | signal 63% | snr 49% | ber 13548 | unc 0 | status S | signal 37% | snr 49% | ber 13420 | unc 0 | status S | signal 62% | snr 49% | ber 13429 | unc 0 | status SC | signal 37% | snr 49% | ber 13627 | unc 0 | status S | signal 60% | snr 50% | ber 12929 | unc 0 | status S | signal 31% | snr 49% | ber 13116 | unc 0 | status S | signal 54% | snr 49% | ber 13085 | unc 0 | status S | signal 75% | snr 49% | ber 13509 | unc 0 | status S | signal 80% | snr 50% | ber 13017 | unc 0 | status S | signal 62% | snr 49% | ber 13280 | unc 0 | status S | signal 67% | snr 50% | ber 13254 | unc 0 | status S | signal 64% | snr 51% | ber 13167 | unc 0 | status S | signal 62% | snr 49% | ber 13333 | unc 0 | status S | signal 81% | snr 53% | ber 13535 | unc 0 | status S | signal 62% | snr 49% | ber 14173 | unc 0 | status SC | signal 52% | snr 50% | ber 13901 | unc 0 | status S | signal 63% | snr 49% | ber 13795 | unc 0 | status S | signal 83% | snr 53% | ber 13907 | unc 0 | status S | signal 62% | snr 49% | ber 13942 | unc 0 | status S | signal 48% | snr 49% | ber 14070 | unc 0 | status SC | signal 62% | snr 50% | ber 13688 | unc 0 | status S | signal 31% | snr 49% | ber 13815 | unc 0 | status SC | signal 56% | snr 49% | ber 13550 | unc 0 | status S | signal 62% | snr 49% | ber 14052 | unc 0 | status S | signal 32% | snr 49% | ber 14079 | unc 0 | status S | signal 62% | snr 49% | ber 13345 | unc 0 | status S | signal 21% | snr 41% | ber 0 | unc 0 | no FE_HAS_LOCK achievable, both signal levels and snr are too low so I pull out the CAM (and restart gnutv) the lock is immediate : status SCVYL | signal 80% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 80% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 80% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 78% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 79% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK status SCVYL | signal 80% | snr 84% | ber 0 | unc 0 | FE_HAS_LOCK signal is around 80%, snr a consistent 84% I re-insert the CAM, which is detected by gnutv, and the CAM is initialised tuning lock is lost at once : status S | signal 62% | snr 50% | ber 13585 | unc 0 | status S | signal 31% | snr 49% | ber 13498 | unc 0 | status S | signal 82% | snr 49% | ber 13540 | unc 0 | status S | signal 62% | snr 49% | ber 13984 | unc 0 | status S | signal 62% | snr 50% | ber 13548 | unc 0 | status S | signal 57% | snr 51% | ber 13530 | unc 0 | status SC | signal 39% | snr 48% | ber 14016 | unc 0 | status S | signal 57% | snr 49% | ber 13375 | unc 0 | status SC | signal 31% | snr 49% | ber 13870 | unc 0 | status S | signal 62% | snr 49% | ber 13359 | unc 0 | status S | signal 72% | snr 51% | ber 13155 | unc 0 | status S | signal 81% | snr 51% | ber 13120 | unc 0 | status S | signal 75% | snr 49% | ber 13528 | unc 0 | status S | signal 81% | snr 52% | ber 13161 | unc 0 | status S | signal 63% | snr 49% | ber 13402 | unc 0 | status S | signal 82% | snr 53% | ber 13166 | unc 0 | status S | signal 63% | snr 49% | ber 13357 | unc 0 | status S | signal 83% | snr 53% | ber 12724 | unc 0 | status SC | signal 60% | snr 49% | ber 13034 | unc 0 | status S | signal 82% | snr 52% | ber 13347 | unc 0 | status S | signal 63% | snr 49% | ber 13640 | unc 0 | status S | signal 67% | snr 49% | ber 13273 | unc 0 | status S | signal 62% | snr 50% | ber 14039 | unc 0 | even though the signal level drops, it's probably the drop in snr that's causing trouble both cards have the same problem, so it doesn't appear that they're defective (or they both happen to have the same fault, which is unlikely) question time : > how much of a chance do I have of solving this if I somehow increase the signal strength ? would that increase the snr too ? (I could shorten the cables, even if it means relocating the PC) > without the CAM, I have a signal strength of 80%. Is that considered a good, strong signal ? (my settop box is happy with it) > I asked in a previous post if it's possible to capture scrambled to disk, and descramble later. This is what my settop box does. Is this even theoretically possible (sending data to the CAM from a file instead of from the tuner) ? Anybody know of a utility that supports this ? and now I'm off installing W2K on the damn thing, to see if that works ... Luc _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
