[mythtvnz] Using Universal Multi-LNB (D1 & D2)

[Johan Schuld]

Hi Dean,

Thanks for your lengthy response. I have tried your suggestion, I
think I have started off with a config similar to as you suggest but
as I have tried so much I can't completely remember:) I also tried
both DiSEqC options in myth but no luck.

I have been doing a bit more research on the web en logfiles, and I
did identify something which might point to the problem.

First thing I verified was the DiSEqC command. I actually looked up
the specs at Eutelsat, and the command Myth sends down (verified with
Mythtvsetup -v all) seems correct. There is not much difference
between the committed command and the non-committed command. What is
interesting thoug, is the frequency myths reports trying to tune to.
The log outputs:

 "2008-06-25 23:49:03.246 DVBChan(2:0): Tune(): Tuning to 9737544kHz"
(See complete log section below)

Compared to my working dvbstream log output:

"tuning DVB-S to Freq: 1856000, Pol:H Srate=22500000, 22kHz tone=off,
LNB: 1 " (See complete log secton below)

See the difference? 1856000 (dvbstream) vs 9737544 (myth). Now this
could be simply a log error so would be good if anyone could try it
with a working setup. The log entry is generated when searching for
channels (12456 22500000 3/4 Horizontal)

On a side note: the -tone option does not do anything. It does not
generate an error, nor does it have an effect. Maybe it depends on the
version.

In addition, in the dvbstream output it lists "tone=off", which I
assume is the 22khz tone. I expect this to be on, as we want the
higher band. Given that dvbstream works, I tried the same in mythtv by
selecting a custom LNB, using the normal frequencies (Low=9750,
High=10600) but setting the switching frequency very high (12750).
Unfortunately still no luck, but also a bit of a trail-error as I have
not found a way to verify if that 22khz tone is there or not (I'm
almost getting the scope out to verify)

So still trying away here. I am a bit out of options at the moment,
and considering I might need to think about a Motec dish motor, given
that the reception of D2 is very bad anyway. Does anyone have
experience with that?

Thanks for all the input so far,
Cheers,
Johan.

LOGS:

Log from mythtvsetup -v all
------------------------------------------------------------------
2008-06-25 23:49:02.884 SIScan(0): Starting SIScanner
2008-06-25 23:49:02.885 SIScan(0): Tuning to Frequency 12456 mplexid(0)
2008-06-25 23:49:02.887 MSqlQuery: SELECT diseqcid, value FROM
diseqc_config WHERE cardinputid = 29
2008-06-25 23:49:02.929 DiSEqCDevTree: Changing to DiSEqC switch port 1/2
2008-06-25 23:49:02.930 DiSEqCDevTree: Sending DiSEqC Command: e0 10 39 f0
2008-06-25 23:49:03.245 DVBChan(2:0): Old Params: 0 auto a auto auto a
a auto a v
                        DVBChan(2:0): New Params: 12456 qpsk a auto
auto a a auto a h
2008-06-25 23:49:03.246 DVBChan(2:0): Tune(): Tuning to 9737544kHz
2008-06-25 23:49:03.288 dvbchannel.cpp:wait_for_backend: Status:
2008-06-25 23:49:03.288 DVBChan(2:0): Tune(): Frequency tuning successful.
2008-06-25 23:49:03.289 DTVSM(0)::SetChannel(-1, -1):
2008-06-25 23:49:03.290 SM(0)::Start: begin
2008-06-25 23:49:03.290 SM(0)::AddFlags: Seen() Match() Wait(Sig,)
2008-06-25 23:49:03.291 SM(0)::Start: end
2008-06-25 23:49:03.335 SM(0)::AddFlags: Seen() Match() Wait(Sig,)
2008-06-25 23:49:03.371 SM(0)::AddFlags: Seen() Match() Wait(Sig,)
-----------------------------------------------------------------------------------------------------------


log from dvbstream -f 12456 -s 22500 -p h -D 1 -v 513 -a 651 -o > teststream
-------------------------------------------------------------------------------------------------------------
dvbstream v0.6 - (C) Dave Chapman 2001-2004
Released under the GPL.
Latest version available from http://www.linuxstb.org/
Tuning to 12456 Hz
Using DVB card "Conexant CX24123/CX24109", freq=12456
tuning DVB-S to Freq: 1856000, Pol:H Srate=22500000, 22kHz tone=off, LNB: 1
DISEQC SETTING SUCCEDED
Getting frontend status
Event:  Frequency: 12456000
        SymbolRate: 22500000
        FEC_inner:  3

Bit error rate: 0
Signal strength: 63744
SNR: 65148
FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI FE_HAS_SYNC
dvbstream will stop after -1 seconds (71582788 minutes)
Output to stdout
Streaming 2 streams
---------------------------------------------------------------------------------------------------------------------------



>Hi Johan
>
>Looks like you're on the right track - but you might need some slight
>tweeks to get this to work with your LNB.
>
>0) Tone, Voltage, Band, Polarity
>
>Band == Tone
>Polarity == Voltage
>
>The receiver signals the LNB which Band and Polarity to use by setting
>the Tone and Voltage on the line.
>
>No 22kHz = Low Band
>22 kHz = High Band
>
>18V = horizontal
>13V = vertical  (I always get those reversed so you might like to check
>them)
>
>So where ever you have a chart with  Band and Pol you can think of it
>in terms of what Tone and Voltage you need to send to select them.
>
>
>Right - on with the show, lets start from the beginning.
>
>1) Universal LNBs
>
>Universal LNBs are used primarily in Europe to solve a particular
>problem....  Too many channels =)
>A standard LNB has an offset of something like 11300 and can tune into
>signals in the 12.25GHz to 12.75GHz
>
>The problem in Europe is that this isn't enough of a band for all the
>channels.  So they came up with a second band and used Universal LNBs
>which you can tell which band you want to tune to.
>Here are some example specs form a Universal LNB.
>
>Low Band: 10.7 ~ 11.7 GHz
>High Band: 11.7 ~ 12.75 GHz
>L.O. Frequency
>Low Band: 9.75 GHz
>High Band: 10.6 GHz
>
>So you can see that if the Frequency is lower then 11.7 GHz then you
>need the low band and if it's higher thatn 11.7GHz then you're in the
>high band.
>
>
>The reason I'm explaining this is because ALL channels you're going to
>be able to pick up in this part of the world are higher than 11.7GHz
>and therefore in the high band.
>As above, to select the high band you need to send the LNB a 22kHz
>tone.  So you essentially want to send this always.
>
>I've essentially hardcoded tone on some LNBs in the past by configuring
>them with a tiny low band and a huge high band, but lets only worry
>about that if it becomes a problem.
>
>
>2) Dual throat Universal LNBs
>
>So you have one of these where you use DiSEqC switching to choose which
>of the throats to listen to.
>This is subtlly different to the system which I have, but it makes it
>easier for you.  All you really need is the following setup
>
>
>Switch (DiSEqC)--------Universal LNB A
>		  |____Universal LNB B
>
>You don't need to do tone switching because you always need the
>tone on. You also don't need to do voltage switching because your
>channel selection will take care of that. So you really only need to
>get that DiSEqC switch sorted. There are only two DiSEqC settings on
>MythTV, these are 'Committed' and 'Uncommited' which correspond to
>DiSEqC 1.0 and 1.1.  DiSEqC 2.0 which you have is based on one of the
>earlier standards but incorporates the ability to interrogate the
>switch to see which way it's been switched to. So even
>though Myth doesn't have specific 2.0 support, it might still be
>backward compatible.  So you're going to need to try both settings.
>
>
>
>3)  Questions.
>
>1: Where in the logs can I find what kind of decision Mythtv made on
>Diseqc, Tone and Voltage. This way I can correlate my setting with
>what I actually need. Now it's just trail and error, and don't like
>that.
>
>Probably nowhere as it's not logged by default =).  Restart the backend with "-verbose channel" >and you should see these sorts of things.
>
>2: Can I change the tone setting in dvbtune? Then I can check if this
>works with my LNB (=Diseqc 2.0) or it's just a fluke it's working with
>dvbtune. I can't find it in any manual/synax I found on the net.

>You can.  I use --tone


>3: In your example, you select select as LNB "Universal" (10600) for
>SatA-Tone. How can this work if you already took care of the
>tone/voltages ?
>
>of the 6 LNBs I have on my system only one of them is a Universal.  I use them on the switching >matrix so that I can have  control over the Tone setting.  I have found the Tone-Switch within Myth >to be a bit unreliable.
>
>If I want tone sent to an LNB (or to my switch to switch to that LNB) then I set it up as a Universal >with a low band of 0-0.001GHz (ie tiny) and a high band of 0.001GHz to 20GHz (ie the whole >band).  This way when Myth is looking at which band it needs to select, it's always going to be >High Band, and it will set tone.   Similarly I can reverse these and get an LNB which will never >have tone sent to it.

>It's a bit of a hack but it works better for me than the MythTV tone switch.