[linux-dvb] Freecom DVB-T USB stick - no signal

Patrick Boettcher patrick.boettcher at desy.de
Mon Apr 17 22:03:39 CEST 2006


Hi,

On Mon, 17 Apr 2006, Simon Blandford wrote:
> Here is the output from tzap...
>
>   [simon at simon ~]$ tzap "BBC NEWS 24"
>   using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
>   reading channels from file '/home/simon/.tzap/channels.conf'
>   tuning to 505833333 Hz
>   video pid 0x0280, audio pid 0x0281
>   status 20 | signal ffff | snr ffff | ber 00000000 | unc 00000000 |
>   status 20 | signal ffff | snr ffff | ber 00000000 | unc 00000000 |
>   status 20 | signal ffff | snr ffff | ber 00000000 | unc 00000000 |
>   status 20 | signal ffff | snr ffff | ber 00000000 | unc 00000000 |

The mechanism inside the firmware of your device is not getting along 
with "offset frequencies" as they can be found in any of the uk-files for 
linux-dvb.

I don't know why the used offset is taken into consideration in the tuning 
files, IMHO and afaik for DVB-T always the center-frequency should be used 
and afaik all recent dvb-t demodulators are able to compensate "large" 
carrier offsets (up to 300 kHz or more). OTOH, of course the problem here 
lies in the driver/firmware.

To cut things shorter: Can you try to tune to 506 MHz instead of 505.833 ?

> Notice the unfeasible signal strength. When I scan Crystal Palace on Kaffeine 
> it momentarily shows 100% signal and 100% s/n but finds nothing.

Please try to ignore the signal strength and SNR, they are running crazy 
when you don't have any lock.

> Not sure which one of those should equate to video0 and audio0. Maybe that is 
> where the problem lies?

No, audio and video is just for device with MPEG2-decoder onboard.

HTH,
Patrick.

--
   Mail: patrick.boettcher at desy.de
   WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/



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