[linux-dvb] Twinhan DST / TS204 and signal quality questions

["Werner Johansson" <wj@yodel.net>]

Hi all!

I have been lurking around here reading the archives for quite some time,
experimenting with my Linux TV setup consisting of four Twinhan cards (three
VP-1020A sat and one VP-3021 ter), but now I have a few questions for all
you gurus out there! :)

What seems strange about these Twinhan sat cards is that the signal quality
and strength indications seems very low compared to what I get on my two
regular STBs (one Philips/Canal Digital branded box and one Viasat branded
Thomson DSI-35TH). All the sat equipment is connected to a Thomson SWID 98 C
multiswitch fed with 4x2 signals from two quad LNBs pointed at 1W and 5E.
Having tried different ports on the multiswitch they all behave the same,
tried different cabling as well with no difference.

Also I have sat cards from two batches (one card with serial # starting with
0312 and two consecutive numbered cards starting with 0401), both giving the
same results (roughly signal ~ 0x3c00 - 0x3d00 and snr ~ 0x1500 - 0x1900),
which seems really low compared to the 80-90% quality and strength I get
from the STBs??

Not that I don't get any picture out of this, I do, but I get occational
break-ups due to broken TS packets (and this is never seen on the STBs,
perfect quality there).

The TER card is behaving more or less in the same way, but there I know that
I have some bad signal coming in (even an STB I tried had issues with my
roof-top antenna), but here I actually get higher values (signal ~ 0x52xx -
0x5300 and snr ~ 0x5c00 - 5d00).

Looking at the dst frontend log output I can see that the sat cards all
identify themselves as "DST-03T" with symdiv and ts204 flags set, whereas
the ter card says "DTTDIG" and no flags set.

So the main questions that comes out of this would be:
Can the BER and UNC values actually be read out of these cards (I have seen
other tuners where only one or the other could be read out), or will I have
to scan the TS streams for error bits instead to get some idea of the actual
amout of corrupt TS packets?

Are these values I get "nominal" for Twinhan cards?

The TS204 flag, would that imply that the Reed-Solomon FEC has not been done
on the card itself, or are the last 16 bytes of data just junk from the
correction process?

For the record, this is running on Fedora Core 2, stock kernel 2.6.7 with
linuxtv-apps-1.1.0 for tuning.

A lot of questions from one confused Swede at the moment.. :)

Regards
Werner

Log output below for the four cards:

Linux video capture interface: v1.00
bttv: driver version 0.9.15 loaded
bttv: using 8 buffers with 2080k (520 pages) each for capture
bttv: Bt8xx card found (0).
ACPI: PCI interrupt 0000:02:03.0[A] -> GSI 11 (level, low) -> IRQ 11
bttv0: Bt878 (rev 17) at 0000:02:03.0, irq: 11, latency: 32, mmio:
0xda000000
bttv0: detected: Twinhan VisionPlus DVB-T [card=113], PCI subsystem ID is
1822:0001
bttv0: using: Twinhan DST + clones [card=113,autodetected]
bttv0: gpio: en=00000000, out=00000000 in=00f2c9ff [init]
bttv0: using tuner=4
bttv0: add subdevice "dvb0"
bttv: Bt8xx card found (1).
ACPI: PCI interrupt 0000:02:04.0[A] -> GSI 5 (level, low) -> IRQ 5
bttv1: Bt878 (rev 17) at 0000:02:04.0, irq: 5, latency: 32, mmio: 0xda002000
bttv1: detected: Twinhan VisionPlus DVB-T [card=113], PCI subsystem ID is
1822:0001
bttv1: using: Twinhan DST + clones [card=113,autodetected]
bttv1: gpio: en=00000000, out=00000000 in=00f2e1ff [init]
bttv1: using tuner=4
bttv1: add subdevice "dvb1"
bttv: Bt8xx card found (2).
ACPI: PCI interrupt 0000:02:05.0[A] -> GSI 12 (level, low) -> IRQ 12
bttv2: Bt878 (rev 17) at 0000:02:05.0, irq: 12, latency: 32, mmio:
0xda004000
bttv2: detected: Twinhan VisionPlus DVB-T [card=113], PCI subsystem ID is
1822:0001
bttv2: using: Twinhan DST + clones [card=113,autodetected]
bttv2: gpio: en=00000000, out=00000000 in=00f247ff [init]
bttv2: using tuner=4
bttv2: add subdevice "dvb2"
bttv: Bt8xx card found (3).
ACPI: PCI interrupt 0000:02:06.0[A] -> GSI 12 (level, low) -> IRQ 12
bttv3: Bt878 (rev 17) at 0000:02:06.0, irq: 12, latency: 32, mmio:
0xda006000
bttv3: detected: Twinhan VisionPlus DVB-T [card=113], PCI subsystem ID is
1822:0001
bttv3: using: Twinhan DST + clones [card=113,autodetected]
bttv3: gpio: en=00000000, out=00000000 in=00fb5cfe [init]
bttv3: using tuner=4
bttv3: add subdevice "dvb3"
bt878: AUDIO driver version 0.0.0 loaded
bt878: Bt878 AUDIO function found (0).
ACPI: PCI interrupt 0000:02:03.1[A] -> GSI 11 (level, low) -> IRQ 11
bt878(0): Bt878 (rev 17) at 02:03.1, irq: 11, latency: 32, memory:
0xda001000
bt878: Bt878 AUDIO function found (1).
ACPI: PCI interrupt 0000:02:04.1[A] -> GSI 5 (level, low) -> IRQ 5
bt878(1): Bt878 (rev 17) at 02:04.1, irq: 5, latency: 32, memory: 0xda003000
bt878: Bt878 AUDIO function found (2).
ACPI: PCI interrupt 0000:02:05.1[A] -> GSI 12 (level, low) -> IRQ 12
bt878(2): Bt878 (rev 17) at 02:05.1, irq: 12, latency: 32, memory:
0xda005000
bt878: Bt878 AUDIO function found (3).
ACPI: PCI interrupt 0000:02:06.1[A] -> GSI 12 (level, low) -> IRQ 12
bt878(3): Bt878 (rev 17) at 02:06.1, irq: 12, latency: 32, memory:
0xda007000
attach: checking "bt878 #0 [hw]"
find by pci: checking "bt878 #0 [hw]"
attach: "bt878 #0 [hw]", to card 0
attach: checking "bt878 #1 [hw]"
find by pci: checking "bt878 #1 [hw]"
attach: "bt878 #1 [hw]", to card 1
attach: checking "bt878 #2 [hw]"
find by pci: checking "bt878 #2 [hw]"
attach: "bt878 #2 [hw]", to card 2
attach: checking "bt878 #3 [hw]"
find by pci: checking "bt878 #3 [hw]"
attach: "bt878 #3 [hw]", to card 3
DVB: registering new adapter (DST).
DVB: registering new adapter (DST).
DVB: registering new adapter (DST).
DVB: registering new adapter (DST).
spurious 8259A interrupt: IRQ7.
bt878 find by dvb adap: checking "DST"
dst_check_ci: recognize DST-03T
DST type : satellite
DST type flags : 0x2 ts204 0x4 symdiv
DVB: registering frontend 0:0 (DST SAT)...
bt878 find by dvb adap: checking "DST"
dst_check_ci: recognize DST-03T
DST type : satellite
DST type flags : 0x2 ts204 0x4 symdiv
DVB: registering frontend 1:0 (DST SAT)...
bt878 find by dvb adap: checking "DST"
dst_check_ci: recognize DST-03T
DST type : satellite
DST type flags : 0x2 ts204 0x4 symdiv
DVB: registering frontend 2:0 (DST SAT)...
bt878 find by dvb adap: checking "DST"
dst_check_ci: recognize DTTDIG
DST type : terrestial TV
DST type flags :
DVB: registering frontend 3:0 (DST TERR)...