On 04.12.2012 20:35, cedric.dew...@telfort.nl wrote:
Hi All,

I use an USB DVB-T receiver. This works ok, but the snr meter at the bottom
of the screen is never filled more than a few pixels, no matter how good
the signal is. The problem with this receiver is that the snr figure never
goes above 0x00d0. Is there a way to adjust the scaling of the signal and
snr bars? I would like the snr bar to be fully filled when the figure is

Best regards,

$ lsusb
Bus 001 Device 004: ID 2013:0245 PCTV Systems PCTV 73ESE

$ tzap -a 0 -r 'Nederland 1'
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
reading channels from file '/home/cedric/.tzap/channels.conf'
tuning to 474000000 Hz
video pid 0x1b63, audio pid 0x1b64
status 1b | signal 0dbd | snr 00a2 | ber 001fffff | unc 00000000 | FE_HAS_LOCK

$ dmesg
[ 3.519233] dvb-usb: found a 'Pinnacle PCTV 73e SE' in cold state, will
try to load a firmware
[ 3.529962] dvb-usb: downloading firmware from file 'dvb-usb-dib0700-1.20.fw'
[ 3.871202] dib0700: firmware started successfully.
[ 4.373456] dvb-usb: found a 'Pinnacle PCTV 73e SE' in warm state.
[ 4.373567] dvb-usb: will pass the complete MPEG2 transport stream to
the software demuxer.
[ 4.373732] DVB: registering new adapter (Pinnacle PCTV 73e SE)
[ 4.568680] DVB: registering adapter 0 frontend 0 (DiBcom 7000PC)...
[ 4.766795] DiB0070: successfully identified
[ 4.830021] Registered IR keymap rc-dib0700-rc5
[ 4.831325] input: IR-receiver inside an USB DVB receiver as 
[ 4.831485] rc0: IR-receiver inside an USB DVB receiver as 
[ 4.831681] dvb-usb: schedule remote query interval to 50 msecs.
[ 4.831688] dvb-usb: Pinnacle PCTV 73e SE successfully initialized and

It's a real pitty that the DVB drivers don't provide a standardized way of
getting signal strength and quality. They all deliver some bogus values
in various different ranges, which are pretty useless to applications.
That's why VDR's cDvbTuner tries to work around this deficiency in its
cDvbTuner::GetSignalStrength() and cDvbTuner::GetSignalQuality() functions by
scaling the individual values so that they fall into a defined range of 0..100.
See these functions in dvbdevice.c and how they use the subsystemId to set
an individual maximum value for the "TT-budget S2-3200". Maybe you can do 
similar for your device.
Please send me a proper patch if you have any success with this.


P.S.: ceterum censeo: the DVB drivers should finally get an interface that 
these values right away. After all, the driver is the only place where this can 
done reasonably. It wouldn't even matter whether the range is 0..100, 
or anything else - just the *same* for all drivers! Or does this already exist 
I just missed it?

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