On 26/09/17 22:45, Vincent McIntyre wrote:
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.
I had very good reception and scandvb tuned to all channels. I did not test
dvbv5-scan again but I expect it would work too (will try in the morning).
Regards
Vince
--
Eyal Lebedinsky (eyal@xxxxxxxxxxxxxx)
