[linux-dvb] Re: Tuning problems with TT DVB-C 1500 (saa7146 +stv0297) and QAM128

Toni Lindroos tonilind.ml at nic.fi
Mon Aug 22 13:06:04 CEST 2005

On Sunday, August 21, 2005 9:29 PM,
Patrick Boettcher <patrick.boettcher at desy.de> wrote:

> Toni, don't case about the signal and snr values as longas ber and
> unc is 0. Most of the signal and snr calculation stuff need
> floating-point-operations which can't be done in a kernel module,
> this the signal and snr values depend on the modulation-driver and
> are most of the time "incorrect".


> Besides the long time it takes for to get a lock the reception looks
> good to me. Do you still have problems when watching video?

Well, if I can get it to lock to a channel, then there are no problems. 
Picture and sound are OK. But it's really occasional to get a lock... 
Sometimes it takes maybe 5 seconds but sometimes it can take several minutes 
(depending on what channel I'm trying).

I put the card again into my Windows machine and checked how things are with 
TT's software. Tuning usually takes about 1-2 seconds, sometimes a few 
seconds longer - seems to be OK. Signal quality is always 100 % and signal 
level is changing between about 60-70 %. I tried to use an antenna amplifier 
but that didn't make any notable difference in those levels (the label on 
the device says VHF/UHF/FM Amplifier, freq. 40-862 MHz, gain 20 dB, gain 
control -12 dB, noise figure 5 dB, max. output 85 dBuV). BTW, if I unplug 
the antenna cable the signal level shown is about 87 %. ;-)

My friend (who is a programmer) is going to try to make your stv0297 code 
working with the current CVS code. He doesn't have access to a network with 
QAM128 modulation or a DVB-C adapter with stv0297 but he'll use my linux box 
over SSH.

Toni Lindroos <tonilind.ml@*NOSPAM*nic.fi>
Turku, Finland 

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