[mythtv-users] Unicable problems
Klaas de Waal
klaas.de.waal at gmail.com
Sat May 28 08:42:36 UTC 2022
On Wed, 25 May 2022 at 07:52, Klaas de Waal <klaas.de.waal at gmail.com> wrote:
> On Wed, 18 May 2022 at 23:15, Matthias Thyroff <matthias at thyroff.net>
>> Hi everybody,
>> after years using my mythbox with great success and relatively little
>> suffering, I had to move my server to a location a bit further away from
>> the sat dish and there is only one cable available so I decided to
>> switch to unicable and this is quite a headache... I think I have
>> several problems, I am not even sure where to start. Maybe I first
>> describe what I have:
>> I have a Selfsat H50DCSS antenna - a flat satellite antenna with
>> incorporated 2x legacy and 1x unicable connections.
>> I have the unicable connection fed through the window and there
>> connected to the inhose coax cable that originally was laid for cable
>> tv. At the location of the receiver at the other end of that cable, I
>> have a 1-to-4 splitter (alternatively 1-to-2), connected to my SAT
>> inputs - a digital devices cine S2 V6.5 card plus one DuoFlex S2
>> extension card (which does not seem to work, I keep that pending for
>> I am also running four loopback devices (link 0:4, 1:5, 2:6, 3:7, this
>> is working) .
>> Then I have four input cards defined, one for each loopback device, from
>> adapter 4 to 7.
>> Card 1: /dev/dvb/adapter4/frontent0; type DVB-S, delivery system dvb-s2,
>> DiSEqC Unicable (Userband 0, 1210MHz, Pin -1, repetitions I tried 1, or
>> 9, or 15, works all the same), type LNB (Universal-LNB (Europe))
>> Card 2: same for adapter 5, except Userband 1, 1420.
>> Card 3: same for adapter 6, except Userband 2, 1680,
>> Card 4: same for adapter 7, except Userband 3, 2040.
>> Video Source, one defined. Name "Unicable". Only EIT, frequencies
>> europe-west, etc. etc.
>> Input connections: Card 1 and 2 connected to unicable, card 3 and 4 for
>> now to "nothing", for later trouble shooting (these to cards error out,
>> the other two cards show as available in the frontend).
>> Input connections are configured fast tuning "never".
>> I think that is a relatively complete description of the setup.
>> Scanning for channels was quite difficult - I could never do a complete
>> scan (tuned), so I switched to a legacy input on the antenna, then I
>> scanned, and once I had the transponders, I could switch back to
>> unicable and do a full scan of all known transponders. I would get about
>> 600 channels less and many transponders which would have signal on the
>> legacy output of the antenna do not have signal on the Unicable output,
>> but nothing important seems to be missing, so that is OK for now. I also
>> have optimized the antenna orientation with a sat finder, I think that
>> made it much better. With the 4x Splitter while scanning, I get about
>> 64% Signal and S/N of about 25%, if that means anything. Reception seems
>> to be stable for now.
>> Several things seem to not work very well, but right now only one
>> problem is consistant and (finally, thanks for reading up to here) I
>> dare to ask for help:
>> It seems I can only watch or record one channel even though I have two
>> working cards. Once a program is recording, I can still enter live tv, I
>> see the same channel as is recording, I can switch between the two
>> sources (Called SAT#1 and SAT#2), but I cannot change channel, neither
>> on the card busy with the recording (I have configured the input to
>> allow for 2 concurrent recordings, so I should be able to switch to
>> another channel on the multiplex). nor can I change the channel on the
>> second card, it will also only tune to the channel that is currently
>> recorded on the other card.
>> One solution that occurs to me is to create another video source for the
>> second card - I have not tried, I do not know whether that would work
>> but that was not necessary in the past, one video source would work for
>> several tuner cards. So I hope to get a better suggestion from you.
>> Thanks a lot in advance!
>> Could it be that both your tuners are configured to use the same
> userband/frequency? That would explain the behavior of your tuners.
> A thing to keep in mind is that the GUI for this part of the configuration
> is really crappy.
> As described in the DiSEqC part of the Channel Scanning wiki, you will
> need to do an escape/save after every configuration step and then do the
> next configuration step, otherwise configured values are sometimes not
> So I suggest to check the userband/frequency configuration of each tuner.
I have some results after first testing with my new Unicable LNB pointed to
The LNB documentation counts the userbands from 1 upwards, e.g. userband 1
is 1210MHz. MythTV allows configuring from 0 upwards; I can receive
something if I configure userband 0 and 1210MHz, and with userband 1 and
1420MHz etc. This could be a bug in MythTV but for now it works.
Selecting the correct LNB type is still a bit fuzzy. As I understand it,
with Unicable you send the frequency to the LNB and then the LNB tunes to
that frequency and downmixes the received signal back to the selected
userband. This means that dealing with the details on how to actually tune
a specific satellite signal is hidden in the LNB, only the frequency should
With the default "Universal" I get no results at all. I suspect that there
is then a conflict in LNB settings between the Unicable part of the LNB and
the tuner card.
I get the best results now with LNB configured as "LNB Preset: Custom" and
"LNB Type: Legacy".
Can you experiment with this and post the results?
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