[linux-dvb] Some tests on Avermedia A700

Eduard Huguet eduardhc at gmail.com
Mon Feb 11 10:20:13 CET 2008

En/na Eduard Huguet ha escrit:
> 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.
> Regards,
>   Eduard

By the way (sorry if I'm being molest...): I will leave the card in this 
PC for now, as it's easier fo me to test and develop. As I have also 
Windows here ¿is there any way we could do any reverse enginnering from 
Windows driver, etc...?


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