[linux-dvb] Some tests on Avermedia A700

Eduard Huguet eduardhc at gmail.com
Wed Feb 13 16:37:43 CET 2008

En/na Matthias Schwarzott ha escrit:
> On Sonntag, 10. Februar 2008, Eduard Huguet wrote:
>> En/na Matthias Schwarzott ha escrit:
>>> On Samstag, 9. Februar 2008, Eduard Huguet wrote:
>>>> Hi, Matthias
>>> Hi Eduard!
>>>>     I've been performing some tests using your patch for this card.
>>>> Right now neither dvbscan nor kaffeine are able to find any channel on
>>>> Astra (the sat. my dish points to).
>>>> However, Kaffeine has been giving me some interesting results: with your
>>>> driver "as is" it's getting me a 13-14% signal level and ~52% SNR when
>>>> scanning. Then, thinking that the problem is related to the low signal I
>>>> have I've changed the gain levels used to program the tuner: you were
>>>> using default values of 0 for all (in zl1003x_set_gain_params()
>>>> function, variables "rfg", "ba" and "bg"), and I've changed them top the
>>>> maximum (according to the documentation: rfg=1, ba=bg=3). With that, I'm
>>>> getting a 18% signal level, which is higher but still too low apparently
>>>> to get a lock.
>>>> I've stopped here, because I really don't have the necessary background
>>>> to keep tweaking the driver. I just wanted to share it with you, as
>>>> maybe you have some idea on how to continue or what else could be done.
>>> So I can do only this guess:
>>> I changed demod driver to invert the Polarization voltage for a700 card.
>>> This is controlled by member-variable voltage_inverted.
>>> static struct mt312_config avertv_a700_mt312 = {
>>>         .demod_address = 0x0e,
>>>         .voltage_inverted = 1,
>>> };
>>> Can you try to comment the voltage_inverted line here (saa7134-dvb.c:
>>> line 865).
>>> BUT: If this helps we need to find out how to detect which card needs
>>> this enabled/disabled.
>>> Regards
>>> Matthias
>> Hi,
>>   Nothing :(. Removing (or setting it to 0) the voltage_inverted member
>> doesn't seem to make any difference. I'm starting to suspect that there
>> is something wrong with my antennae setup, so I'll test it later using
>> an standalone STB or by plugging the card into a Windows computer and
>> using the supplied drivers.
> Even better: Tune to a channel and measure the voltage the card outputs on LNB 
> connector.
> Regards
> Matthias
Oops :D. Could you please elaborate a bit on this? I don't know what is 
the LNB connector you are referring to. Plus, I don't have right now any 
voltimeter, but if needed I'll grab one from work tomorrow.


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