[linux-dvb] DiSEqC switch blinded by KNC tuner [was: KNC1 TV Star DVB-S tuning problem]

Doru Marin Doru.Marin at Deuromedia.ro
Wed Jan 30 19:34:08 CET 2008


I changed my Gigaswitch 11/20 multiswitch with other model and instantly 
my card got working.
First I thought that is a DiSEqC error, so I had to check with other 
switch model. And, surprisingly, it start to work.
So, I reverted back and tried to figure out what's happen. After several 
tests, I concluded that it works fine with any vertical channels, low/hi 
switch and even sat switch.
So I figured out that the horizontal requests cause the troubles. I 
measured  the output on tuner and  I'm getting 13.5V for vertical and 
19.2V for horizontal.
I changed in the stv0299 code and I'm lowering the power to 13V during 
DiSEqC command.With this hack, I'm successfully tune on horizontal 
channels, too.
But this is a hack and doesn't sound right. According to specs, the 
voltage switch should occur before DiSEqC commands.
The older KNC type card uses stv0299 too and it behaves better with my 
switch. And also gets 19V on output.

Finally, it seems that the KNC TV Star card blinds my switch.
Any ideea how to fix this without hacking the stv0299 driver ?

Thanks in advance,

Doru Marin wrote:
> Hello,
> I got two KNC DVB-S cards, an older one (1894:0010) and a new KNC TV 
> STAR model, (1894:0016) on  FC6 running last kernel (2.6.24).
> The old card works fine, I have no problems with it. The second one, 
> after I tune o a channel on a vertical polarity, doesn't want to tune on 
> any horizontal channel anymore:
> # szap -c ./astra.conf -a0 "BBC World"
> reading channels from file './astra.conf'
> zapping to 3 'BBC World':
> sat 0, frequency = 11597 MHz V, symbolrate 22000000, vpid = 0x00a3, apid 
> = 0x005c sid = 0x2742
> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
> status 03 | signal d9a0 | snr 965d | ber 0000db00 | unc 00000000 |
> status 1f | signal e100 | snr dd9d | ber 00005e00 | unc 00000000 | 
> ...........
> #  szap -c ./astra.conf -a0 "ZDF"
> reading channels from file './astra.conf'
> zapping to 161 'ZDF':
> sat 0, frequency = 11953 MHz H, symbolrate 27500000, vpid = 0x006e, apid 
> = 0x0078 sid = 0x6d66
> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
> status 03 | signal b3e0 | snr 9be2 | ber 00009e00 | unc 00000000 |
> status 03 | signal b3d1 | snr a71c | ber 0000ff30 | unc 00000000 |
> Back to "BBC World", it locks fine. but no chance to lock on ZDF anymore.
> If I replug the sat cable, it starts to work again, until I switch again 
> on a "V" channel.
> I checked the polarity switch, the card delivers 19.2V, so there is no 
> power problem.
> The difference between cards is the tuner, the new one uses a Philips 
> SD1878.
> As long as the first card works like charm, I assume the the sat switch 
> works fine.
> Any idea what goes wrong, anyone ?
> Regards,
> Doru
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