Tetra decoding

[sq5bpf]

When I (before starting scan) tune (using GRC interface) to 390.2125 network is detected at MANY frequencies from 390.7125 to 392.675!
Maybe it "telive issue" or hackrf problem.

maybe the hackrf can't sample at 256ks/s without aliasing? (this is a bit of a problem in rtl-sdr at slow sample rates, because the antialiasing filter is wider than the nyquist frequency).

could you try the flowgraphs without "slow" in the filename, these will run at 2Ms/s?


unfortunately i can't support hardware which i don't own. hint hint

 

[sq5bpf]

short demo of the new version:

- lauch the receiver, in this case we'll use the 6 channel receiver without gui, and with the xmlrpc control interface (you can also use the 1 channel version for slow devices):

cd telive/gnuradio-companion/receiver_xmlrpc
./kill_wrapper ./telive_6ch_gr37_udp_xmlrpc_headless.py

- launch decoder processes:

cd osmo-tetra-sq5bpf/src
for i in `seq 1 6`; do xterm -T RX$i -e ./receiver1udp $i & done

- launch telive (first set the correct PPM value in rxx)
cd telive
./rxx

press t - this will show the frequency window

press Q - this will start scanning, the results will be in telive_frequency.log

press d after some scanning - this will write a report of found frequencies to telive_frequency_report.txt


pressing d will return to normal receiver mode

if rx auto-tuneis enabled, then telive will tune all channels automatically from received frequency info


i will put this all in the docs, but writing them will take a while

 

[bilbolodz]

Sorry I've made a mistake. I was using: telive_1ch_simple_gr37_udp_xmlrpc.grc with 4M sampling.
I'm waiting for next rtl stick from ebay to come but HackRF is much more powerful then rtl stick.

 

[CqDx]

Hi all,

Currently trying to modify the flowgraph to enable playback of recorded IQ files. I believe I can get the file piped through gnuradio, but I just get AFC: -0.05xxx instead of the detailed TETRA info. Any help please...?

 

[sq5bpf]

Currently trying to modify the flowgraph to enable playback of recorded IQ files. I believe I can get the file piped through gnuradio, but I just get AFC: -0.05xxx instead of the detailed TETRA info. Any help please...?

"it should work"

my guess is that either the format is wrong, or the signal isn't tuned properly.

i can try myself if you give me access to one of these files, but i will do it after writing the docs (which is harder than programming btw)

 

[sq5bpf]

Sorry I've made a mistake. I was using: telive_1ch_simple_gr37_udp_xmlrpc.grc with 4M sampling.

this should proably work without any changes (only the sample rate)

I'm waiting for next rtl stick from ebay to come but HackRF is much more powerful then rtl stick.

i know. the only problem with the hackrf is that i don't have one

btw you should find similar S/N fromt the rtl-sdr dongle, because this also uses a 8 bit adc

 

[bilbolodz]

i know. the only problem with the hackrf is that i don't have one

You should it's a good stuff.

btw you should find similar S/N fromt the rtl-sdr dongle, because this also uses a 8 bit adc

Yes I know. It's not a problem of S/N ratio.

BTW.: When I'm trying to "scan" Tetra working on 390.2125 which base frequency should I use?
When I put 390M scanning is started from 390.5. As I understand scan only finds channels on frequencies

Base_freq + 0.5M + n * 12.5k ?

 

[strom_asap]

I think, i have found some "bugs" in telive/osmo-tetra. For a long time i have GSMTAP errors (Malformed and Unconstrained warnings) in dumped .pcap files for a Wireshark from my TETRA network. Errors are:

Malformed:
1 type of error: PDU->MAC-RESOURCE. Error maybe there -> ssi-usage-maker->other->tm-sdu:bl-udata->bl-udata:cmce->cmce: d-Setup
2 type of error: PDU->MAC-END-DOWNLINK. Somewhere in this type of PDU.

I have mostly "d-Setup" type of malformed packets (maybe 100-300 malformed packets from 1 GB .pcap file from 8 AM till 3 PM).

Unconstrained:
exactly there PDU->MAC-RESOURCE-> ssi-usage-maker->other->tm-sdu:bl-udata->bl-udata:mle->mle:d-restore-ack pdu type:1

There are 10-20 of this type of warnings in 1 GB .pcap file

Sometimes a have "Malformed" and "Unconstrained" label on single GSMTAP packet.

So the problem is that i can`t hear some parts of recordered audio traffic, and i think osmo-tetra or telive "marks" d-Setup and d-restore-ack GSMTAP packets as false malformed. So i can`t listen a conversation between 2 TETRA users without gaps (sometimes).

 

[CqDx]

"it should work"

my guess is that either the format is wrong, or the signal isn't tuned properly.

i can try myself if you give me access to one of these files, but i will do it after writing the docs (which is harder than programming btw)

Here is the file on dropbox. Many thanks for taking a look into it!

https://www.dropbox.com/s/6yispe0s2w5xyg3/14-35-53_397875kHz.wav?dl=0

For your information, I captured the spectrum using SDRsharp using Airspy 10 Mbps sampling rate. The baseband was captured using 8 bit PCM. I then saved this file using "IF Recorder" plugin and saved the file using IF Recorder plugin using 16 bit PCM IQ sampling.

 

[sameehosen]

Hello
After updating telive
Here are some pictures
I have a push button Q and then button D
I did not see nothing has changed
Am I on the right track

 

[bilbolodz]

I think you are using NOT xmlrpc version of grc script.

 

[sameehosen]

Thanks for your reply
Yes, because I used GNURADIO 3.6
I can not run attached files with a folder xmlrpc

 

[bilbolodz]

To scan XMLRPC is a must, telive use it to control "sdr device" set qrq and other stuff.

 

[sameehosen]

Another reason for a friend
Nothing in xmlrpc run 3 channels File Folder

 

[henrygb]

What could be wrong?
All was fine before update to telive 1.9

Using GNU Radio Companion 3.7.5, USB Realtek RTL2838.

What file have to use?
receiver_pipe, receiver_udp or receiver_xmlrpc

Tried with old grc file (it work fine before televe 1.9), now have error ### SMALL FRAME and no audio
Tried with new grc, telive_1ch_gr37.grc and have error ### SMALL FRAME and no audio too

Was update "osmo-tetra-sq5bpf" folder and "telive" folder (git pull, make)

 

[bilbolodz]

I've tried to play a little with scanning. Because I don't have a "spare rtl stick" I've used HackRF One.

Scanning with rtl stick (even "over the network" with rtl_tcp) is working much better than with HackRF.
Some question:

Could you please explain function of "baseband auto correction, and working of "automatically tune receiver"?
After some tries I've manage to have tuner 1 to 4 tuned to "right frequency" reported in tetra messages but actually I don't know how I did it ;-)
One more question:
Tuners are set, telvie reports messages "about frequencies" but "Known frequencies" area is empty???

 

[sq5bpf]

i've added a preliminary version of the docs for version 1.9, as usual the document is here:

https://github.com/sq5bpf/telive/raw/master/telive_doc.pdf

if you find any errors/omissions/something should be made more clear please report it


also please report any errors in the new telive version. i already know that that the frequency info is broken.

 

[bilbolodz]

also please report any errors in the new telive version.

How to report problems with telive? On forum in thread or create issue on github?

 

[sq5bpf]

i've added a minor tweak to the install_telive.sh script to allow installation under raspbian 8

after installation run gnuradio-companion once, and close it (this will generate the necessary config files, this can probably be done in some non-gui way, but i didn't investigate it). this can be done either on the local X display (if installed) or X11 can be tunneled via ssh -X ....

i used raspbian 8 minimal with a raspberry pi 2 model b. without an x server running (all ran via ssh and under screen), and with the telive_1ch_gr37_udp_xmlrpc_headless_slow.py all software uses about 20% of the cpu in scanning mode.


also beware NOT to run volk_profile , and erase ~/.volk/volk_config if you did. for some reason optimisation doesn't work on this raspberry.


i will put this in the docs later

 

[sq5bpf]

How to report problems with telive? On forum in thread or create issue on github?

via email, via the forum or github (but i don't read the issues often)