[linux-dvb] Re: Cinergy 1200 DVB-T TDA10046H / auto mode causes problems

[Andrew de Quincey <adq_dvb@lidskialf.net>]

On Friday 19 Nov 2004 14:33, Christian Cier-Zniewski^ wrote:
> Hi,
>
> Andrew de Quincey schrieb:
> >Hi, I tried the sample of that card I have out. However, the one I have
> > gives terrible reception - errors constantly. I know it isn't the signal
> > because all other types of DVB-T card in the same machine give a perfect
> > signal. I assume the signal you're getting is OK, otherwise you would
> > have mentioned it.
>
> The transmitting antenna is approximately 1km away from my machine.
> Could it be possible that the signal is to strong? AFAIK they are
> transmitting using a power of 50kW.
> I am using a small telescope antenna.

I'm using a full digital TV aerial on the roof. I must be over 20Km away from 
the transmitter (Black Hill). I'm not sure about the power issue anyway - 
(almost) the same tuner/demod combo works fine on the TT USB box.

There are even pictures of the transmitter here for some reason :)
http://tx.mb21.co.uk/gallery/blackhill.asp

> >There are two possible causes as far as I can see:
> >
> >1) I've heard these cards are supposed to be quite picky about PCI buses.
> >Certainly dvbtune reports a BER of 0 from the demod, but the actual data
> >received by my test program is full of errors.
>
> I have used VDR with the femon plugin to display the frontend status.
> STR and SNR do not show any values most of the time.

Yeah - I seem to remember there were some strange problems on the USB box with 
those measurements as well - sort of jumping between 0 and a large value.

> If I switch to a satellite channel, the femon plugin displays meaningful
> values. So I assume that the plugin is working correctly at least.
>
> >2) Could there be some difference in the type of signal? The one I am
> > trying is:
> >
> >frequency: 634166670
> >bandwidth: 8Mhz
> >hp-rate: FEC_3_4
> >lp-rate: FEC_3_4
> >modulation: qam-16
> >transmission-mode: 2K
> >guard-interval: 1/32
> >hierarchy: none
> >
> >The only other time I tried this demod (tda10046) was on a TT USB Nova-T.
> >However, it worked fine there.
>
> frequency: 746000000
> bandwidth: 8Mhz
> hp-rate: FEC_2_3
> lp-rate: FEC_2_3
> modulation: qam-16
> transmission-mode: 8K
> guard-interval: 1/4
> hierarchy: none
>
> BTW: Is there a history of the different tda1004x dsp firmware revisions?
> The one in the CVS seems to be version v20. I know that v26 exists. Did
> you try this one?

I did yes, but it made no difference. the TDA10046 works perfectly on the TT 
USB budget box with the firmware in CVS though.