Tetra decoding

[sq5bpf]

It actually froze just 3 seconds after it started and by scrolling up and down in terminal continued.
(you have to actually click inside and use scroll button)
Thou been running fine since then so erh i dunno.

does it restart when you scroll some other window with a lot of text?
are you using xterm, or some other terminal (and if so, please change to xterm and see if it persists)

which window stalls? telive or tetra-rx (receiver1)? if tetra-rx, then does it happen when you throw away the output? (try this: ./receiver1 1 >/dev/null 2>&1 )

 

[noamlivne]

One network works fine, while another one does not

Hi Jacek,
Thank you very much for your app and efforts.

Your app works well for me with one Tetra network, but for some reason I have grave issues with another network.
I use the same computer and configurations for both of the networks. One network is in the 393Mhz area and the other is on the 937Mhz area.
The problematic network is very strong - so no reception issues.

I am not a technical guy but one of the main differences I can see is that the problematic network has this line all the time:
CRC COMP: xxxxxx WRONG

Maybe this causes the issues?

I am attaching logs from the "normal" network and from the "problematic" one.
By the way the "normal" network is received quite weak from a neighboring country, but it works fine. The problematic network is probably a local network and it is received excellent but does not seem to work.

I hope this is not too much trouble for you and that you will find the solution easily.

I'll be glad to assist you further with more logs or information.
Thanking you in advance,
Noam

 

[sq5bpf]

you will get wrong crc for voice traffic, however i see that the MCC changes in telive.log, which may be because of interference, or something in the network which is not demodulated correctly.

for interference try to lower the gain or use a different offset value. for example if your network is on 937.150, then you can use 937M baseband and 150k offset, or 936.5M and 650k offset etc... maybe there are some other strong signals (like gsm) in the passband which are interfering with the receiver or with the AGC, by manipulating the offset you can get them out of the rtl2832 passband. or maybe you hear multiple cells? (drive around with the laptop to find out).

bw what country is this? i've never seen tetra on 937MHz.

 

[noamlivne]

Thank you very much for your reply.

I am afraid the MCC changed because of a momentary reception issue. This was my mistake. Sorry.
It usually did not change.
If needed I can send a better log with a "strange" but steady MCC number - but still with the CRC COMP WRONG.

The neighboring country, from which I pick up the weak but valid 393Mhz network is Egypt. So you can deduce what country I am talking about with regards to the strong signals in the 937Mhz area.

Well, if this network is using a non-conventional frequency - maybe it has other strange parameters or protocols such as the CRC COMP(?).

I tried fine tuning the frequency - which is the solution for both the networks to "start streaming" data. The data stream works in both of the networks but gives WRONG CRC in the strong network.

I did not feel that changing the IF Gain had any effect.
The SDR Gain is most of the time on the maximum but I do not think that is the culprit. I will play with that too.

I did not try changing the Offset. I will give it a try on the weekend probably.
I hope that will help but I am pessimistic.

Thank you again.

 

[jlxsolutions]

Tonight it halted on this and did not restart on clickanscroll
never seen this before and i do not have any freq like that in gnuradio???

RESOURCE Encr=2, Length=16 Addr=SSI + Usage Marker(13576770/U20) ChanAlloc=Quit and go (TN7/Downlink only/366612500Hz) sq5bpf req mle_pdisc=0 req=0

 

[jlxsolutions]

Also could you expand on this in the documentation?

"The telive program shows a list of possible usage identifiers (0-63, where 0-2 are reserved),"

seeing alot of ssi'is in in there 0-2

 

[sq5bpf]

Also could you expand on this in the documentation?

"The telive program shows a list of possible usage identifiers (0-63, where 0-2 are reserved),"

seeing alot of ssi'is in in there 0-2

0-3 are reserved. if you see this, then please send me telive.log


btw i will not do any tetra stuff, or reply in this forum until early october

 

[jlxsolutions]

dosenyt seem to be anything that intresting this is all i been finding in log with the ssi showing up in usesage indentifier 0 havent been much traffic today thou

20150919 22:27:54 FUNCSETUPDEC IDX:0 SSI:12074114 CID:15828 NID:25 RX:4
20150919 22:51:40 FUNCSETUPDEC IDX:0 SSI:186053 CID:6592 NID:29 RX:4
20150919 23:23:15 FUNC-SDS DATA SSI:04999025 IDX:000 IDT:1 ENCR:0 RX:4
20150919 23:23:15 FUNCSETUPDEC IDX:0 SSI:15728679 CID:7778 NID:63 RX:4

 

[noamlivne]

you will get wrong crc for voice traffic, however i see that the MCC changes in telive.log, which may be because of interference, or something in the network which is not demodulated correctly.

for interference try to lower the gain or use a different offset value. for example if your network is on 937.150, then you can use 937M baseband and 150k offset, or 936.5M and 650k offset etc... maybe there are some other strong signals (like gsm) in the passband which are interfering with the receiver or with the AGC, by manipulating the offset you can get them out of the rtl2832 passband. or maybe you hear multiple cells? (drive around with the laptop to find out).

bw what country is this? i've never seen tetra on 937MHz.

Hi Jacek,
Sorry for the delayed response.
I even tried this strange network with a new and more powerful computer, and by changing the offset as you recommended.
Nothing helps. The CRC COMP is always WRONG.
Maybe it is a non-standard network and I will simply forget about it for the time being.
The "regular" network works fine.

Thank you again for your help and Best Regards.

 

[asgard]

hi, i'm shame to say that but someone can help me to install telive via team viewer?
I tryed to install on debian 8, kali 2.0, ubuntu 14 and now ubuntu 15.04.. i have manny error at installation.. i tryed to solve-it after manny nights spent google-it but my knowledge in linux are minimal (read none)..
i really want to install and use this sw so if is someone who want to kill some time with me.. please
br

 

[ET-NL]

Technical question.

On a network where Air encryption is enabled.
Is it possible to have one group using encryption while the other group is communicating without encrytpion. (all on the same network, same MCC/MNC/CC/LA).
For example the security GSSI (and all of the ISSI's in this group) are using encryption for there communication while the cleaners are just using plain Tetra ?

 

[sam_q]

hi, i'm shame to say that but someone can help me to install telive via team viewer?
I tryed to install on debian 8, kali 2.0, ubuntu 14 and now ubuntu 15.04.. i have manny error at installation.. i tryed to solve-it after manny nights spent google-it but my knowledge in linux are minimal (read none)..
i really want to install and use this sw so if is someone who want to kill some time with me.. please
br

What errors do you have when try to install on debian with the script?

 

[jlxsolutions]

Technical question.

On a network where Air encryption is enabled.
Is it possible to have one group using encryption while the other group is communicating without encrytpion. (all on the same network, same MCC/MNC/CC/LA).
For example the security GSSI (and all of the ISSI's in this group) are using encryption for there communication while the cleaners are just using plain Tetra ?

inshort yes definetly yes

 

[ET-NL]

inshort yes definetly yes

Thanks for the answer. This was the answer I was hoping for

 

[asgard]

What errors do you have when try to install on debian with the script?

At first it was libzmq1-dev error, i solved, after that i have manny times error after compilling gnu radio.. after that i have error in some module after finishing with succes compilling gnu radio.. Today i wiped out all and installed fresh ful debian 8. I'm affraid to start all process ). So.. help will be needed . By the way.. i don't know how to set sudo for privileges for my user to start all proces .. google-it.. but..
br

 

[asgard]

At first it was libzmq1-dev error, i solved, after that i have manny times error after compilling gnu radio.. after that i have error in some module after finishing with succes compilling gnu radio.. Today i wiped out all and installed fresh ful debian 8. I'm affraid to start all process ). So.. help will be needed . By the way.. i don't know how to set sudo for privileges for my user to start all proces .. google-it.. but..
br

i tryed to de LE but not work.. so i managed to add user in sudores files, and tryed to run script:
in short list , i have this :


Proceed?y
Starting all functions at: Sat Sep 26 09:58:00 EDT 2015
SUDO privileges are required
Do you have SUDO privileges?y
Continuing with script
[sudo] password for q:
Installing prerequisites.
====> THIS MAY TAKE QUITE SOME TIME <=====
Unsupported Debian version 8.2
br,

 

[nam-shub]

Many thanks to SQ5BPF for this useful software !

I just uploaded a software that can do the basic functions of telive, but headless, without the requirement for a fixed-size terminal. I also wanted to rewrite it in python so it was a bit easier to read. If anyone is interested you can find it here:
https://github.com/nam-shub/tetra_recorder

It's probably very buggy, it's only received light testing so far.

It does NOT support:
location decoding/logging
SDS texts

The reason is that these things are not used on the networks I see. It should be very easy to add support, if anyone is interested.

In the future I hope to simplify the pipeline, create a python tuner/demodulator that combines the GRC flowgraph and simdemod2.py. I have written such a thing but it's not ready, it loses sync a lot because of some bug.

Again, thanks to the osmo-tetra guys and SQ5BPF for their excellent work, without them I could not do this.

 

[sm0vec]

Many thanks to SQ5BPF for this useful software !

I just uploaded a software that can do the basic functions of telive, but headless, without the requirement for a fixed-size terminal. I also wanted to rewrite it in python so it was a bit easier to read. If anyone is interested you can find it here:
https://github.com/nam-shub/tetra_recorder

It's probably very buggy, it's only received light testing so far.

Thanks for the script, I gave it a try and noticed some areas of possible improvement:

- First a bug; The list of SSI for a 'channel / index' is not forgotten after a call is completed, hence the next call get all previous SSI's, plus the new. And in the end the string becomes too long and the software crashes.

- The 'channel / index' as you used, and also SQ5BPF have based Telive, should only be used to separate different streams. It's the Call ID which makes each session unique and a call (identified by the Call ID) can span over several 'channels / indexes'. On a site with several physical channels (frequencies), there can more than one simultaneous call on the same 'channel /index' since this only have to be unique per physical channel (many systems have indeed different indexes allocated to each physical channel, but many new systems I've use the same range of indexes on each physical channel which makes the audio unintelligible since it's a mix between two voice streams when index is used as the identifier)

- The SSI are in some functions padded with zero which means that the same call appears several time in the SSI depending from which function it was captured.

- Finally a feature request... It's not too difficult to separate the GSSI from SSI (by looking in the ETSI standard), so for group calls it would be great to have the GSSI first in the file to easily be able to see which group that was used.

 

[sm0vec]

Technical question.

On a network where Air encryption is enabled.
Is it possible to have one group using encryption while the other group is communicating without encrytpion. (all on the same network, same MCC/MNC/CC/LA).
For example the security GSSI (and all of the ISSI's in this group) are using encryption for there communication while the cleaners are just using plain Tetra ?

Even though jlxsolutions already answered this clearly I would like to add that I also seen TEA2 systems with encryption=1 where some users and groups are unencrypted. Both location information and calls are sent open.

I guess the authorities in this country did so to be able to let in users which according to the ETSI rules not should be granted a TEA2 license (read private persons in a non-governmental organization). However in a neighboring country the same kind of users are though using TEA2, but maybe they shouldn't either.

 

[nam-shub]

Thanks for the script, I gave it a try and noticed some areas of possible improvement:

- First a bug; The list of SSI for a 'channel / index' is not forgotten after a call is completed, hence the next call get all previous SSI's, plus the new. And in the end the string becomes too long and the software crashes.

I think I fixed that bug last night, let me know if it's still there and I'll take a look.

- The 'channel / index' as you used, and also SQ5BPF have based Telive, should only be used to separate different streams. It's the Call ID which makes each session unique and a call (identified by the Call ID) can span over several 'channels / indexes'. On a site with several physical channels (frequencies), there can more than one simultaneous call on the same 'channel /index' since this only have to be unique per physical channel (many systems have indeed different indexes allocated to each physical channel, but many new systems I've use the same range of indexes on each physical channel which makes the audio unintelligible since it's a mix between two voice streams when index is used as the identifier)

Thanks for the hint, I'll look into that. It seems the TETRA systems I see do split based on channel (subchannel? not sure what the ETSI standard calls this thing that telive calls "usage"). I'll try to rework it to track call_ids across channels at some point.

- The SSI are in some functions padded with zero which means that the same call appears several time in the SSI depending from which function it was captured.

Hmm, you mean the leading zero? That's how tetra-rx sends it. I can try to strip it, but is it guaranteed that no number will ever start with a zero? I should probably look better at the telive code here...

- Finally a feature request... It's not too difficult to separate the GSSI from SSI (by looking in the ETSI standard), so for group calls it would be great to have the GSSI first in the file to easily be able to see which group that was used.

[/QUOTE]

I was originally thinking of doing this (IIRC, the GSSI can be gotten just by looking at the SSI parameter to D-SETUP) but from the standard it looked like group-IDs were temporarily assigned and not persistent. Is it still useful to implement this?


Thanks for your feedback, looks like I have to read more of the ETSI standards...