Tetra decoding

[jlxsolutions]

use telive_1ch_simple_gr37.grc file in there you then get the clieckety click spectrum as well where you can tune in on frequency
and sample rate is the box on top left that says samp_rate 2M just change the 2 to a 1

 

[sq5bpf]

I posted error logs of gnuradio companion when i try to lauch the .grc files ...

after reinstalling Mint 17.2 + telive

you have gnuradio 3.7. the files with _gr37 in the name are for gnuradio 3.7.x, the ones without _gr37 are for gnuradio 3.6. this is why you're seeing errors. so for example instead of telive_1ch.grc use telive_1ch_gr37.grc (or better telive_1ch_simple_gr37.grc, but that might take too much cpu)

btw did you read the docs? this is explained there.

 

[oz1jua]

GNU Setup grc files.

When we talk about setup grc files. Does any one here know haw to setup a better receiver for receive Tetra.
I have an HackRF and a AirSpy 1. It seems that the AirSpy is more sensitiv, and has a better rejection for near by strong signal. Can it be done to archive a better setup with filters etc. to better reject this.
I am not an expert in settting up a readio reciever.

But what is best to use as center freq. Ex. if Center Freq is set to 425 Mhz and then use offset +500 Kz. for recieving 425.500 Mhz. Is this acceptable or schould the offset be extended. Or what is best.

Right now I use my AirSpy with a 3.1 db attenuation filter and if I just set the sdr-gain and sdr-ifgain right then i have the best result for receiving better signals. I have seen that the sdr-ifgain never must exceed 6.
Then it seems to work.

 

[sq5bpf]

When we talk about setup grc files. Does any one here know haw to setup a better receiver for receive Tetra.
I have an HackRF and a AirSpy 1.

sorry, but i don't have either an airspy nor an hackrf (and don't plan on buying them)

but if i ever get them i will try to support grc files for there receivers.

please look at the osmosdr source documentation for these receivers. most proobably you just need to change the gain/samplin rate settings and this will work out of the box

 

[FR3500]

you have gnuradio 3.7. the files with _gr37 in the name are for gnuradio 3.7.x, the ones without _gr37 are for gnuradio 3.6. this is why you're seeing errors. so for example instead of telive_1ch.grc use telive_1ch_gr37.grc (or better telive_1ch_simple_gr37.grc, but that might take too much cpu)

btw did you read the docs? this is explained there.

Ok thanks again !
Obviously i read the docs ; of course i tried the 3.7 versions first, but as i said they don't work, i can't use the graph window; then i just tried the first .grc's , hoping tey would work, i didn't notice in the pdf that they don't work with 3.7

I think i'll have to install Ubuntu 14.04 instead, and do the manual install, with gr3.6
Maybe lighter version for my laptop ?

 

[sq5bpf]

I think i'll have to install Ubuntu 14.04 instead, and do the manual install, with gr3.6
Maybe lighter version for my laptop ?

maybe try debian 8 and install using the install_telive.sh script?

debian can be made very light, just use a lightweight desktop environment like xfce

 

[grosminet]

osmosdr-tetra_demod_fft.py should work but don't

osmosdr-tetra_demod_fft.py should work with sdrplay but don't . It is a question of sample rate .

for exemple we modified the "fcdp-tetra_demod.py" and the "fcdp-tetra_demod_fft.py" to make this work with funcube pro + (9600 to 192000) -funcube pro + is 192 k sample rate

For the sdrplay , we have the values : 2 MSPS-10.66 MSPS means 2 000 000 to 10 600 000 for equivalent

When I modify these values , I have the same problem

What line I have to modify , to make this work

osmosdr-tetra_demod_fft.py is compatible with gr-osmosdr

(sdrplay Use this argument without a value )

any help is welcome and sorry for so bad english

 

[sq5bpf]

osmosdr-tetra_demod_fft.py should work with sdrplay but don't . It is a question of sample rate .

but why use that? the scripts user with telive have the advantage of decoupling the receiver from the rest (which is in the receiver1 script: psk demodulator in simdemod2.py, float-to-bits, tetra-rx).

so you have a nice and simple grc flowgraph, easy to understand and modify. did you try to just use telive_1ch_simple_gr37.grc? the 2M sample rate seems to be supported in sdrplay, so just some parameters will need tweaking (ppm, the various gains etc). you might need to have a recent driver as the older ones don't work in 380-420MHz (the blog and faq talks about this). this is required in gnuradio, regardless which software you will use as the receiver. the sdrplay website has nice descriptions how to build a compatible gr-osmosdr. see the following pages:


SDRplay - Linux

from the blog:
SDRplay - Blog

Friday 14th August 2015
We have now released our updated API - the new API fixes the frequency gap we have had up until now (previous gap was 380MHz to 420MHz worst case) -. It has been completely removed. .

btw i don't own an sdrplay. but if someone sends me one i can publish a detailed document how to get it to work

 

[sq5bpf]

using the receiver with low sample rate

A short howto on how to run the receiver with 250ksamples/s sample rate (this is the lowest that the dvb-t dongles permit). This is intended for devices which don't have a lot of cpu horsepower. A few minor tweaks are needed, this is for the telive_1ch_simple* scripts, but others can be modified in the same way:

- change samp_rate to 250000

- change xlate_offset to 50000

- change first_decim to 4

- if you don't need the spectrum displays disable them as well

- if you are really cpu constrained (or would like to have a console-only application), then drop the WX gui stuff altogether (disable in the top_block, disable all WX GUI widgets)

 

[grosminet]

telive_1ch_gr37.grc

I tried telive_1ch_gr37.grc with sdrplay (verified with gqrx) . I have no error but no signal imput

I tried Cubic SDR with soapy SDR , I can run RTL SDR and SDRplay running fine . What i'm lacking is the relationship between IQ of cubicsdr (via pulseaudio) and the fifo (/dev/pulseaudio ??)

Cubicsdr is alpha release but it is an alternative to GQRX . GQRX has IQ design for a long time but had never been developped

That would be an unique interface for SDR hardware with all settings include to TETRA or other protocol

 

[sq5bpf]

I tried telive_1ch_gr37.grc with sdrplay (verified with gqrx) . I have no error but no signal imput

so both telive_1ch_gr37.grc and gqrx show no signal? maybe you have a bad version of sdrplat and gr-osmosdr libraries (the one with the hole in 380-420MHz).

do other frequencies work? for example can you see signals in the 88-108MHz band with telive_1ch_gr37.grc and gqrx?

Cubicsdr is alpha release but it is an alternative to GQRX . GQRX has IQ design for a long time but had never been developped

That would be an unique interface for SDR hardware with all settings include to TETRA or other protocol

i have no immediate plans to support receiving with cubicsdr or gqrx. gnuradio is much more flexible than that, and usually gets support for new sdr hardware much quicker than other receivers.

please see the descriptions on the sdrplay website regarding gnuradio support, it should be really simple, and probably you're just doing some simple mistake (old library, some parameter not set correctly like gain, antenna input etc)

also if i ever get my hands on sdrplay hardware i will publish a description o how to make it work.

 

[point2point]

Using Telive from remote source

Hi Everybody,

Is there somebody who can help me with a remote host setup ?
I have a location where i run RTL_TCP (or can run anything there on the raspb pi2)
Locally everything works fine but i can't manage to let the osmo block connect to a remote host.
I know i can push the UDP packets to another host but i takes a lot of bandwidth, i would like to set it to 1M and let it connect with TCP to the rtl_tcp daemon.
On the location i have 40 mbits upload, can somebody show me an example of a GNU config connecting to a remote host with Telive ?
Thank you for your attention.

Paul

 

[sq5bpf]

On the location i have 40 mbits upload, can somebody show me an example of a GNU config connecting to a remote host with Telive ?

read the osmosdr source block help (you can see it when you edit the osmoosdr block):

The osmocom source block:

While primarily being developed for the OsmoSDR hardware, this block as well supports:

[...]
* RTL-TCP spectrum server (see librtlsdr project)
[...]


Examples:

Optional arguments are placed into [] brackets, remove the brackets before using them! Specific variable values are separated with a |, choose one of them. Variable values containing spaces shall be enclosed in '' as demonstrated in examples section below.
Lines ending with ... mean it's possible to bind devices together by specifying multiple device arguments separated with a space.

[...]
rtl_tcp=127.0.0.1:1234[,psize=16384][,direct_samp=0|1|2][,offset_tune=0|1] ...

so you would probably use the following in the Device Arguments section:

rtl_tcp=1.2.3.4:1234

where 1.2.3.4 is the raspberry pi IP and 1234 is the rtl_tcp port

 

[passie101]

Is it possible to select or configure an specific sound card for each telive session ?

 

[sq5bpf]

Is it possible to select or configure an specific sound card for each telive session ?

playing is done via the tplay script, which internally uses aplay.

so just create multiple directories, copy tplay to each of them, and modify each script do have aplay use a different sound card (add -D XXX to aplay, where XXX is the pcm name, refer to the aplay). put one of the directories first in the PATH for telive, and it will use tplay from this directory.

you can also use pacat instead of aplay to play directly to a pulseaudio sink (and you can specify a remote pulseaudio server too).

 

[passie101]

Thank you this is exact the info I was looking for

 

[sq5bpf]

easier way with pulseaudio:

use pacat it tplay (but only one tplay, no need to use multiple ones), and set the PULSE_SINK (and PULSE_SERVER if you want) variables in rxx scripts. these variables specify the default pulseaudio sink to connect to.

haven't tried it, but it should work

 

[point2point]

Thank you SQ5BPF for the answer about RTL_TCP

I can't figure out where this argument needs to placed.
I open the .grc file do you have a example (google did not help) where i need to put this argument.

<key>title</key>
<value>SQ5BPF Tetra live receiver 1ch demo (gnuradio 37 version)</value>
</param>
<param>
<key>author</key>
<value>Jacek Lipkowski SQ5BPF</value>
</param>
<param>
<key>description</key>
<value></value>
</param>
<param>
<key>window_size</key>
<value>2048, 2048</value>
</param>
<param>
<key>generate_options</key>
<value>wx_gui</value>
</param>

Thanks !

 

[sq5bpf]

Thank you SQ5BPF for the answer about RTL_TCP

I can't figure out where this argument needs to placed.
I open the .grc file do you have a example (google did not help) where i need to put this argument.

but why do you want to edit the grc file directly?

open in gnuradio-companion, right click on the osmosdr source, edit the object properties, put whatever you want into the Device Arguments section and save as a new file.

and while editing the osmosdr source block look at the documentation, which is also avaliable there

 

[wildbillx]

Wondering if anyone has successfully listened to any voice on the New Jersey Transit tetra system? The reason I ask, is because I have not heard any voice tx and have been running it for a few hours. It could be because I am in south jersey with not too much transit traffic.