On Tue, Sep 26, 2017 at 02:32:26PM +1000, Eyal Lebedinsky wrote: > > While the problem persists, I managed to find a way around it for now. > > I changed the antenna input. > > Originally I used a powered splitter to feed all the tuners, and it worked > well with the out-of-kernel driver. This driver does not build or work with > a more modern kernel so I shifted to using dvb_usb_rtl28xxu which fails to > tune. > > The new wiring splits (passive) the antenna in two, feeds one side directly > to the two "Leadtek Winfast DTV2000 DS PLUS TV" cards (through another passive > 2-way) and the other side goes to the old powered splitter that feeds a few > USB tuners. > > Now all tuners are happy. It seems that the "Leadtek Winfast DTV2000 DS PLUS TV" > cannot handle the amplified input while the USB tuners require it. > > I hope that there is a way to set a profile in dvb_usb_rtl28xxu to attenuate > the input to an acceptable level thus unravelling the antenna cables rat-nest. Glad you had some success. I did some more rummaging in v4l-utils. It may help you to know about dvb-fe-tool, which gives information about the frontend device (eg /dev/dvb/adapter0/frontend0). In particular you can monitor the s/n as you make changes: # dvb-fe-tool --femon -a 0 #here doing adapter0/frontend0 It displays info about the signal quality and the carrier/noise (C/N) ratio, which might help any investigation of where the driver fails to cope as you change what you are feeding it. I noticed your dvbv5-scan showed C/N around 20dB but the manpage shows 'good signal' with C/N of 36dB which suggests the device should be expected to deal with higher signal levels. Once you figured out the signal level, did a dvbv5-scan work with no errors? In the example you showed I saw the channels getting 'lock' but then some kind of error occurred. Regards Vince
