tvheadend only finds 4 channels

Marcel Jira

Hi!

From the first look I like tvheadend much more than mythtv - I would like to switch.

However, using a DVB-T-stick (a TechniSat AirStar Telestick 2, tvheadend recognizes it as DiBcom 7000PC) I can only find 4 tv channels - mythtv finds 13 (all that are open to public in my area).

In my area there are 3 muxes that are public available (MUX A, MUX B and MUX C in this list: http://de.wikipedia.org/wiki/Sender_Kahlenberg#TV-Frequenzen - it's in german, sorry). I entered their frequencies and also their other specifications (MUX B and MUX C have a GI of 1/8) to the webinterface. Still only the channels in MUX A can be found.

Is there a way to find the reason of this issue (and maybe even solve it)?

I attach a screenshot to this post.

Thank you

ProfYaffle

What are the other frequencies you've got listed? It's suspicious that you have network and mux IDs on frequencies that aren't listed on that wikipedia page. Are you certain that's your transmitter? What happens if you leave "autodetect muxes" enabled with just MUX A defined?

Marcel Jira

First of all thanks for your answer!

I only entered the frequencies listed on the wikipedia page. The other frequencies appeared when MUX A was detected on 498.000 MHz. If that helps I can post the debug log here.

With "Are you certain that's your transmitter?", do you mean if I really connect to "Kahlenberg" (the transmitter on the wikipedia page)? Well I live in Vienna. There are several transmitters in this area, however all of them use the same frequencies (see http://www.ors.at/fileadmin/user_upload/downloads/Senderliste_Wien_2013-09-05.pdf - again in german -- in this document there are also radio frequencies, the relevant DVB-T frequencies are those with "A-WN", "B-W2" or "C-W1" in the column "Programm").

I'll try to leave autodetect muxes enabled with only MUX A defined today in the evening. I'll report back then.

Thanks!

ProfYaffle

The other thing I'd try is disabling the muxes you don't want... I wonder if the scan is getting stuck on one of the muxes and thus never getting to the services on the other ones.

Check on the config page to see if you have any muxes still awaiting scan, that would give a clue.

What I don't understand is why you have muxes that are identified (ORS DVB-T WN, NetworkID, MuxID) but shouldn't be there according to the information you've posted. If we take 554MHz as an example, that's on neither the wiki page nor the PDF - that's what makes me ask about the Kahlenberg transmitter.

554MHz - Channel 31 - carries MUX-D, which is the DVB-T2 mux - but this is 594MHz/Channel 36 in Vienna:

31 554 MUX-D Bregenz 1 - Pfänder
31 554 MUX-D Bregenz 2 - Lauterach
31 554 MUX-D Feldkirch - Vorderälpele
36 594 MUX-D Mattersburg - Heuberg
36 594 MUX-D Wien 1 - Kahlenberg

36 594 MUX-D Wien 2 - Himmelhof

Okay, I know you can't get DVB-T2 with a DiBcom 7000PC, but it's still suspicious. I haven't checked other (DVB-T) frequencies, particularly the "problem" ones.

(reference here: http://www.satbroadcasts.com/DVB-T_multiplex_MUX-D_in_Austria.html)

Marcel Jira

ok, I removed all the frequencies and readded just 498.000 MHz. Just a few moments later also the other 3 frequencies where back in the table. This is what happened:

http://nopaste.info/ccf9c00238.html

I'm quite confident that also the other frequencies get an initial scan, but I will try this in a moment.

Marcel Jira

Ok, I just disabled the frequencies not listed on the wikipedia page and readded MUX-B and MUX-C (see a picture of the settings for MUX-C below.

Again, the same result: It didn't find any muxes. Also the initial scan took place. This are some lines of the log indicating that:

Jän 23 19:41:50.008 dvb: /dev/dvb/adapter0 stopped thread

Jän 23 19:41:50.008 dvb: "/dev/dvb/adapter0" tuning to "578,000 kHz" (Autoscan)

Jän 23 19:41:54.023 dvb: "578,000 kHz" on adapter "DiBcom 7000PC", status changed to Faint signal

I remember, that I had similar issues when I used the command line tool "scan" from dvb-utils - also just one mux was found. However, using another tool (w_scan) I was able to also find at least all channels on MUX-A and MUX-B.

Here's the output of w_scan:

http://nopaste.info/890eb625fb.html

In fact mythtv was the only program yet that was able to find all muxes (MUX-A, MUX-B and MUX-C).

How can I proceed to locate the cause of this problem?

ProfYaffle

Odd - I genuinely don't understand what's happening here. You're clearly picking up those other muxes (794, 554, 850) when you shouldn't be.

All I can think is that you're picking up muxes from somewhere else, somewhere other than the Kahlenberg transmitter. Without knowing exactly where you are, this is what you should be able to see depending on where your aerial is pointing:

http://www.satbroadcasts.com/DVB-T_Radar_results.html

Could it be that you're pointing at a different transmitter, or (unlikely!) picking up two transmitters in the same line of sight?

What happens if, when you add MUX-B and MUX-C, you only specify bandwidth (8k) and frequency, and leave everything else to Auto?

ProfYaffle

Other random thoughts...

0. Try this link instead of the one above!

http://www.satbroadcasts.com/DVB-T_Radar_results.html?id=NGoyb2EmMWh2Y3I=

1. You're clearly picking up MUX A on 498 and MUX B on 578. That narrows down the transmitters you may be getting, and actually supports Kahlenberg/a transmitter with the same frequencies:


tune to: QAM_16  f = 498000 kHz I999B8C34D0T8G4Y0
(time: 04:10)     service = ORF1 (ORF)
    service = ORF2 W (ORF)
    service = ATV (ATV+)
    service = ORF2 N (ORF)

tune to: QAM_16  f = 578000 kHz I999B8C56D0T8G8Y0
(time: 04:39)     service = PULS 4 (sevenonemedia)tune to: QAM_AUTO f = 522000 kHz I999B8C999D999T999G999Y999
(time: 04:24) Info: no data from PAT
Info: no data from SDT(actual)
Info: no data from NIT(actual)
    service = 3SAT (ORF)
    service = ORF SPORT + (ORF)
    service = ServusTV (ServusTV)
    service = ORF III (ORF)
    service = SchauTV (-)

2. Having DVB-T2 muxes defined shouldn't matter. My DiBcom sees the local DVB-T2 but ignores it; my CXD2820R sees it and processes it, because it can. So having MUX B+ defined shouldn't matter, though disabling them may be wise since it saves even trying to scan.

3. Do you have 'repeater' transmitters? Could you be getting something that only carries MUXes A and B or something like that?

4. What's the 850MHz Mux? It's reported as "ORS DVB-T WN" but I can't see where it should be or what it should carry. I can't find anything in Austria that should be on this frequency (Ch68)... closest is ch69:

69 858 MUX-C Graz - Jakomini
69 858 MUX-C Graz - Plabutsch
69 858 MUX-C Koeflach - Gößnitzberg

69 858 MUX-C Voitsberg - Arnstein

(ref: http://www.satbroadcasts.com/DVB-T_transmitters_in_Austria.html?page=10)

... none of which are near Vienna. Plus 850MHz is dangerously into GSM territory in many places.

I'm afraid that I'm running out of thoughts, though ...

Marcel Jira

Thank you for your help, yaffle! Also sorry for not reporting back so long.

0. My nearest transmitter in fact is "Wien 5 - Arsenal" not Kahlenberg. However, they have the same frequencies (althoug MUX-C is not listed on satbroadcasts.com)
1. Yes :)
2. On tvheadend I think I didn't add any DVB-T2 frequencies... do I?
3. What is a repeater transmitter? I don't know :(

4. I don't know either... On satbroadcasts the nearest transmitter with 850 MHz is in Hungary: http://www.satbroadcasts.com/DVB-T_multiplex_MUX-C_in_Hungary.html ... however, I could imagine that service providers in Austria maybe switched the frequencies some time ago but still keep up the 850 MHz for reasons of "sentimentality". this is just a theory... I could write a mail to ors (which is the regulatory institution for DVB-T services in Austria)... however, does it matter?

Hm, sorry for causing these difficulties. Does tvheadend use some other tool to scan for the muxes (like scan or w_scan)? If this is the case I could maybe try the tool in the command line to get some more debug information?

I could also borrow another DVB-T-stick and try it with this one.

[edit]
In fact MUX-C is listed on satbroadcasts - only it's called MUX-ATV2

ProfYaffle

I'm done, then, I'm afraid. All I can suggest:

1. Try a different stick
2. Try a different system - even if it's Ubuntu on a Live config, or Openelec off a USB.

3. Try w_scan or similar and have a good look at the config files to see if you could create them manually

For (1) and (2) you might be able to create the configs manually (for [1] - you'd need to change the adapter name and dvb device in the config files and name) or copy them over (for [2], assuming the device name is the same). Ugly way to do it, though, and it shouldn't be necessary. I can't think what's wrong. I don't believe tvheadend uses any external programs to scan; I don't know if it uses any of the same file formats either.

While we're floundering with configs, if you can't steal some from someone else in Vienna (anyone reading this? Anyone?) then you could write them from scratch. Once you have one defined, you could stop tvheadend and create the others, turn off idle scanning and restart tvh to see what happens. A real shot in the dark, though... I'm just guessing.

(The "repeater" as another guess - a local transmitter that relays/re-broadcasts some of the muxes but not all - so you're only getting a partial list).

Final random thoughts... what's different about the muxes that work and the ones that don't? Polarisation (is your aerial good? You said mythtv works, so I guess so)? Different guard interval or similar, that perhaps Auto is getting wrong (you can edit the mux configs afterwards, or just look at them to see if it's got the FEC and GI right)? I've never had to play with these - Auto has always worked - but...

Try a different version of tvheadend, just in case you've hit a bug in that code (is this release, nightly, self-build...)?

Sorry, though, I'm rapidly running out of suggestions...

grandma pearl

Hi,

Had the same problem (channels.conf with 14 active DVB-T channels in Vienna while tvheadend only found 4 channels) but your discussion here kept me trying and finally solving the issue.

My hardware: Zotac Zbox Nano AQ01 with an old DVB-T Hauppauge WinTV-Nova-T-lite USB Stick (USB Device ID 2040:7070)
Software: OpenELEC 4 (v4.0.5 at the time of trying), Kernel 3.14.7, tvheadend version 3.4.27~gfbda802

DVB-T Stick is supported out of the box, no additional firmware or drivers necessary.

I configured tvheadend pretty standard:

-->Configuration->DVB Inputs->TV Adapters->General: selecting "DiBcom 7000PC"
-->Configuration->DVB Inputs->TV Adapters->General->Add DVB Network by location...: "Austria"->"at_All"
-->Configuration->DVB Inputs->TV Adapters->General->Adapter configuration: activating checkbox "Enabled"

-->Configuration->DVB Inputs->TV Adapters->General->Adapter configuration: "Save"

System reported 48 Muxes and started to scan.

After the initial scan it found 4 Services (all on MUX-A).

Changed to tab "Multiplexes" and added MUX-B manually according to the information on Wikipedia (http://de.wikipedia.org/wiki/Sender_Kahlenberg#TV-Frequenzen)

-->Configuration->DVB Inputs->TV Adapters->Multiplexes: Add mux(es) manually...
* Frequency (kHz): 578000
* Bandwidth: 8 MHz
* Constellation: QAM-16
* Transmission mode: 8k
* Guard interval: 1/8
* Hierarchy: Auto
* FEC Hi: Auto
* FEC Lo: Auto

-->Configuration->DVB Inputs->TV Adapters->Multiplexes: Save changes

Since I didn't realise any significant change I switched back to the "General" tab after a while, no change there too.
Therefore I continued with some online research only to recognice after some time that the information box indicated 11 services then.

And under the "Services" tab all channels of MUX-B were listed.

So I redid the whole process for MUX-C.

-->Configuration->DVB Inputs->TV Adapters->Multiplexes: Add mux(es) manually...
* Frequency (kHz): 634000
* Bandwidth: 8 MHz
* Constellation: QAM-16
* Transmission mode: Auto
* Guard interval: Auto
* Hierarchy: Auto
* FEC Hi: Auto
* FEC Lo: Auto

-->Configuration->DVB Inputs->TV Adapters->Multiplexes: Save changes

Had to try different settings since "Constellation" to "Auto" did not work.

But with the settings above the scan worked and found another 3 services.

So in total I have now all 14 channels working.

Thanks.

BTW: the nearest transmitter for me is Arsenal.