Sonny_Jim
Posts: 45
Joined: Tue Oct 23, 2012 4:15 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Wed Nov 13, 2013 1:27 pm

You might want to enable some other POCSAG decoders, ie POCSAG512 and POCSAG2400.

Do you have an audio file of what is being received?

Sonny_Jim
Posts: 45
Joined: Tue Oct 23, 2012 4:15 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Sat Nov 23, 2013 4:55 pm

After speaking to the author of rtl_fm it appears there is a problem with the later versions that cause it to stop working with multimon-ng, which he is looking into. For now you'll have to roll back to the earlier commit I posted.

As a little bonus, here's a simple way to listen to the output of rtl_fm in a browser by using socat and sox:

Code: Select all

sudo apt-get install sox socat
 rtl_fm [parameters] | sox -traw -r24k -es -b16 -c1 - -togg - | socat -u - TCP-LISTEN:8080
If you run that then navigate to http://PI_IP_ADDRESS:8080 you should be able to hear what rtl_fm is outputting.

zanco
Posts: 23
Joined: Fri Dec 07, 2012 1:38 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Sun Dec 08, 2013 6:07 pm

Hi,
as far as I know there are no pocsag transmissions at 123.45 MHz. Over here, that frequency is AM airband trafiic for para jumpers and commercial advertising flights.

What kind of pocsag would you like to decode ?

Kind regards,
Ben

urk
Posts: 5
Joined: Thu Dec 19, 2013 12:15 am

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Dec 19, 2013 12:42 am

Hello,

I am a rookie in raspberry pi. I would like to try decoding some transmissions like POCSAG.
At first I needed some days to install wireless connection, but at least it works.
Now I was trying to get this decoding stuff work.
When I try:
rtl_fm -N -o 4 -A lut -s 22050 -C -f 173.240M - | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 -f alpha /dev/stdin

I get this message:
POCSAG512 POCSAG1200 POCSAG2400 EAS UFSK1200 CLIPFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV SCOPE
multimon-ng (C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
(C) 2012/2013 by Elias Oenal
available demodulators: POCSAG512 POCSAG1200 POCSAG2400 EAS UFSK1200 CLIPFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV SCOPE
Enabled demodulators: POCSAG512 POCSAG1200 POCSAG2400
No supported devices found.
What could be wrong? If look at "lsusb" the stick is installed.
Any suggestions? Thanks a lot.
Urk

zanco
Posts: 23
Joined: Fri Dec 07, 2012 1:38 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Dec 19, 2013 12:33 pm

Hi, just a simple test:

run rtl_test without additions. What does it report ?

If the device is listed in lsusb and you have rtl-fm I assume you have installed the rtl-sdr from osmocom ? Did you run make with enabling the udev rules to get non - root user to get access to the usb device ? After that , did you unplug and replug your rtl-sdr (or reboot your PI) ?

Regards,

Ben

urk
Posts: 5
Joined: Thu Dec 19, 2013 12:15 am

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Dec 19, 2013 11:14 pm

Hi,
thx for your quick reply.

When I run that test, I get:

Code: Select all

pi@raspberrypi ~ $ rtl_test
No supported devices found.
I tried howtos from different pages, but the latest and almost working attempt was when following the steps of this howto.

I don't know, if I did the steps you mentioned. Could you give me a hint where to start again?

Here is the output of lsusb:
pi@raspberrypi ~ $ lsusb
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 010: ID 1c4f:0002 SiGma Micro Keyboard TRACER Gamma Ivory
Bus 001 Device 006: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 001 Device 007: ID 0bda:8179 Realtek Semiconductor Corp.
Bus 001 Device 008: ID 2040:f900 Hauppauge
Device 8 is the mentioned stick.

Thanks for your support

Best regards

Urk

zanco
Posts: 23
Joined: Fri Dec 07, 2012 1:38 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Fri Dec 20, 2013 6:51 pm

urk wrote:Hi,
thx for your quick reply.

When I run that test, I get:

Code: Select all

pi@raspberrypi ~ $ rtl_test
No supported devices found.
I tried howtos from different pages, but the latest and almost working attempt was when following the steps of this howto.

I don't know, if I did the steps you mentioned. Could you give me a hint where to start again?

Here is the output of lsusb:
pi@raspberrypi ~ $ lsusb
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 010: ID 1c4f:0002 SiGma Micro Keyboard TRACER Gamma Ivory
Bus 001 Device 006: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 001 Device 007: ID 0bda:8179 Realtek Semiconductor Corp.
Bus 001 Device 008: ID 2040:f900 Hauppauge
Device 8 is the mentioned stick.

Thanks for your support

Best regards

Urk
Hi Urk,

You should start over here http://sdr.osmocom.org/trac/wiki/rtl-sdr at the part: Building the software

At the end they state
In order to be able to use the dongle as a non-root user, you may install the appropriate udev rules file by calling

sudo make install-udev-rules, so when building the software I would run this command instead of just sudo make install.

Let me know where this brings you...

Kind regards,

Ben

urk
Posts: 5
Joined: Thu Dec 19, 2013 12:15 am

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Wed Dec 25, 2013 7:44 pm

Hi Ben,

finally I had the time to try installation again.

The result is again:
No supported devices found.

Below you find my actions and the outputs.
Any idea?
Maybe I would better start with a new image? But installing the wireless connection was not easy...

Thanks for any comment. And merry Christmas!

BR Urk

Code: Select all

pi@raspberrypi ~/rtl-sdr/build $ make
Scanning dependencies of target rtlsdr_shared
[  5%] Building C object src/CMakeFiles/rtlsdr_shared.dir/librtlsdr.c.o
[ 10%] Building C object src/CMakeFiles/rtlsdr_shared.dir/tuner_e4k.c.o
[ 15%] Building C object src/CMakeFiles/rtlsdr_shared.dir/tuner_fc0012.c.o
[ 21%] Building C object src/CMakeFiles/rtlsdr_shared.dir/tuner_fc0013.c.o
[ 26%] Building C object src/CMakeFiles/rtlsdr_shared.dir/tuner_fc2580.c.o
[ 31%] Building C object src/CMakeFiles/rtlsdr_shared.dir/tuner_r82xx.c.o
Linking C shared library librtlsdr.so
[ 31%] Built target rtlsdr_shared
Scanning dependencies of target rtl_adsb
[ 36%] Building C object src/CMakeFiles/rtl_adsb.dir/rtl_adsb.c.o
Linking C executable rtl_adsb
[ 36%] Built target rtl_adsb
Scanning dependencies of target rtl_eeprom
[ 42%] Building C object src/CMakeFiles/rtl_eeprom.dir/rtl_eeprom.c.o
Linking C executable rtl_eeprom
[ 42%] Built target rtl_eeprom
Scanning dependencies of target rtl_fm
[ 47%] Building C object src/CMakeFiles/rtl_fm.dir/rtl_fm.c.o
Linking C executable rtl_fm
[ 47%] Built target rtl_fm
Scanning dependencies of target rtl_power
[ 52%] Building C object src/CMakeFiles/rtl_power.dir/rtl_power.c.o
Linking C executable rtl_power
[ 52%] Built target rtl_power
Scanning dependencies of target rtl_sdr
[ 57%] Building C object src/CMakeFiles/rtl_sdr.dir/rtl_sdr.c.o
Linking C executable rtl_sdr
[ 57%] Built target rtl_sdr
Scanning dependencies of target rtl_tcp
[ 63%] Building C object src/CMakeFiles/rtl_tcp.dir/rtl_tcp.c.o
Linking C executable rtl_tcp
[ 63%] Built target rtl_tcp
Scanning dependencies of target rtl_test
[ 68%] Building C object src/CMakeFiles/rtl_test.dir/rtl_test.c.o
Linking C executable rtl_test
[ 68%] Built target rtl_test
Scanning dependencies of target rtlsdr_static
[ 73%] Building C object src/CMakeFiles/rtlsdr_static.dir/librtlsdr.c.o
[ 78%] Building C object src/CMakeFiles/rtlsdr_static.dir/tuner_e4k.c.o
[ 84%] Building C object src/CMakeFiles/rtlsdr_static.dir/tuner_fc0012.c.o
[ 89%] Building C object src/CMakeFiles/rtlsdr_static.dir/tuner_fc0013.c.o
[ 94%] Building C object src/CMakeFiles/rtlsdr_static.dir/tuner_fc2580.c.o
[100%] Building C object src/CMakeFiles/rtlsdr_static.dir/tuner_r82xx.c.o
Linking C static library librtlsdr.a
[100%] Built target rtlsdr_static
pi@raspberrypi ~/rtl-sdr/build $ sudo make install
[ 31%] Built target rtlsdr_shared
[ 36%] Built target rtl_adsb
[ 42%] Built target rtl_eeprom
[ 47%] Built target rtl_fm
[ 52%] Built target rtl_power
[ 57%] Built target rtl_sdr
[ 63%] Built target rtl_tcp
[ 68%] Built target rtl_test
[100%] Built target rtlsdr_static
Install the project...
-- Install configuration: "Release"
-- Installing: /usr/local/lib/pkgconfig/librtlsdr.pc
-- Installing: /usr/local/include/rtl-sdr.h
-- Installing: /usr/local/include/rtl-sdr_export.h
-- Installing: /usr/local/lib/librtlsdr.so.0.5git
-- Installing: /usr/local/lib/librtlsdr.so.0
-- Up-to-date: /usr/local/lib/librtlsdr.so
-- Installing: /usr/local/lib/librtlsdr.a
-- Installing: /usr/local/bin/rtl_sdr
-- Removed runtime path from "/usr/local/bin/rtl_sdr"
-- Installing: /usr/local/bin/rtl_tcp
-- Removed runtime path from "/usr/local/bin/rtl_tcp"
-- Installing: /usr/local/bin/rtl_test
-- Removed runtime path from "/usr/local/bin/rtl_test"
-- Installing: /usr/local/bin/rtl_fm
-- Removed runtime path from "/usr/local/bin/rtl_fm"
-- Installing: /usr/local/bin/rtl_eeprom
-- Removed runtime path from "/usr/local/bin/rtl_eeprom"
-- Installing: /usr/local/bin/rtl_adsb
-- Removed runtime path from "/usr/local/bin/rtl_adsb"
-- Installing: /usr/local/bin/rtl_power
-- Removed runtime path from "/usr/local/bin/rtl_power"
pi@raspberrypi ~/rtl-sdr/build $ sudo ldconfig
pi@raspberrypi ~/rtl-sdr/build $ cmake ../ -DINSTALL_UDEV_RULES=ON
-- Build type not specified: defaulting to release.
-- Extracting version information from git describe...
-- Building with kernel driver detaching disabled, use -DDETACH_KERNEL_DRIVER=ON to enable
-- Building for version: v0.5.2-3-g1050 / 0.5git
-- Using install prefix: /usr/local
-- Configuring done
-- Generating done
-- Build files have been written to: /home/pi/rtl-sdr/build
pi@raspberrypi ~/rtl-sdr/build $ rtl_test
No supported devices found.

zanco
Posts: 23
Joined: Fri Dec 07, 2012 1:38 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Dec 26, 2013 2:58 pm

This is strange....

If you try sudo rtl_test does that give a different message ?

Other question: What do you use for power supply ? Could it be that there is not enough power for the RTLSDR (in combination with the wifi adapter) ? Can you try to use a powered USB hub ?

My PI is modded, I hardwire bridged the SMD fuse for the USB power output. It gave me about 0,5 Volt power drop when the RTL-SDR was connected...


Let me know the results....

I am mobile reading / posting, did you have the possibility to test the rtlsdr on any other system ?

Regards,
Ben

urk
Posts: 5
Joined: Thu Dec 19, 2013 12:15 am

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Sun Dec 29, 2013 11:38 pm

Hi Ben,

I finally got the time to type those simple words:
sudo rtl_test
result is still the same: No supported device...

I have a powered usb hub. But I will try to disconnect not needed devices.
I have not tried that stick in another system, but I will try on a windows laptop tomorrow.

Can I check somewhere else if the dvb stick is known by the kernel?

I will power down now for disconnecting not needed usb items.

Maybe anyone has an idea?

BR Urk

urk
Posts: 5
Joined: Thu Dec 19, 2013 12:15 am

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Mon Dec 30, 2013 12:26 am

Hi Ben,

Update:
WinTv DVB T stick is working on Windows 7 after 10 minutes installation.
There is a blue LED which was not lighting when plugged in raspberry.
I will check that tomorrow.

There was no success when I plugged out not needed devices and restarting.

So I think I need to get that blue LED lighted, for further steps.

Any idea?

BR Urk

fe_wa
Posts: 1
Joined: Mon Dec 30, 2013 10:34 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Mon Dec 30, 2013 10:46 pm

Hello,
thanks for this great howto!
I've installed the packages on my rpi and have Cinergy DVB-T Stick.
Then I've set the frequency. But multimon says everytime:

pi@raspberrypi ~ $ rtl_fm -N -o 4 -A lut -s 22050 -C -f 172.680M - | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 -f alpha /dev/stdin
POCSAG512 POCSAG1200 POCSAG2400 EAS UFSK1200 CLIPFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV SCOPE
multimon-ng (C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
(C) 2012/2013 by Elias Oenal
available demodulators: POCSAG512 POCSAG1200 POCSAG2400 EAS UFSK1200 CLIPFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV SCOPE
Enabled demodulators: POCSAG512 POCSAG1200 POCSAG2400
Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Terratec Cinergy T Stick RC (Rev.3)
Found Elonics E4000 tuner
Oversampling input by: 12x.
Oversampling output by: 4x.
Buffer size: 7.74ms
Tuned to 172944600 Hz.
Sampling at 1058400 Hz.
Output at 22050 Hz.
Exact sample rate is: 1058400.010094 Hz
Tuner gain set to automatic.
POCSAG1200: Address: 123456 Function: 2
POCSAG1200: Address: CORRUPT Function: CORRUPT
----------------------------------------------------------------------------------
What's wrong? Corrupt isn't good. I can't read the messages. Sometimes i can read one part of a word, but then it says CORRUPT...
Is it normaly that my set frequency (172.680 MHz) Tuned to 172944600 Hz??
Should i change the configuration?

Thanks for your help :).
Felix

Sonny_Jim
Posts: 45
Joined: Tue Oct 23, 2012 4:15 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Fri Feb 28, 2014 3:21 pm

It appears that recently multimon-ng was updated to handle corrupted messages properly:
https://github.com/EliasOenal/multimon- ... b6834546ca

I don't have my Pi setup at the moment so I can't check whether this is a bug with multimon-ng or just that you aren't receiving the signals correctly. You may want to try rolling back multimon-ng to an earlier commit and trying that.

russinnes
Posts: 1
Joined: Wed Apr 16, 2014 3:49 am

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Wed Apr 16, 2014 3:55 am

Heres a small python script that will give you a "PDW" like output.. its a little nicer to read and you can easily mod the code to do what you need, either by text, capcode, etc, etc. Just change the rtl_fm string as required...
this just currently writes to a file and prints to stdout but can easily be modified as you need.

Note: This requires a new build of multimon-ng, as the old one(s) dont accept a piped input. The newest version does.

http://pastebin.com/fFBEmyFf

Cheers

Code: Select all

#!/usr/bin/python

'''

!! This requires a recent build of Multimon-NG as the old builds wont accept a piped input !!

Change the rtl_fm string to suit your needs.. add -a POCSAG512 , 2400 etc if needed to the Multimon-ng string
This just prints and writes to a file, you can put it in a threaded class and pass though a queue
or whatever suits your needs.


'''
import time
import sys
import subprocess
import os

def curtime():
    return time.strftime("%H:%M:%S %Y-%m-%d")

with open('error.txt','a') as file:
    file.write(('#' * 20) + '\n' + curtime() + '\n')

multimon_ng = subprocess.Popen("rtl_fm -f 153980000 -s 22050 -g 40 -p 65 | multimon-ng -a POCSAG1200 -f alpha -t raw -",
                               #stdin=rtl_fm.stdout,
                               stdout=subprocess.PIPE,
                               stderr=open('error.txt','a'),
                               shell=True)

try:
    while True:
        line = multimon_ng.stdout.readline()
        multimon_ng.poll()
        if line.__contains__("Alpha:"):    # filter out only the alpha
            if line.startswith('POCSAG'):
                address = line[22:28].replace(" ", "").zfill(7)
                message = line.split('Alpha:   ')[1].strip().rstrip('<ETB>').strip()
                output=(address+' '+curtime()+' '+ message+'\n')
                print address, curtime(), message
                with open('pocsag.txt','a') as f:
                    f.write(output)
        if not "Alpha:" in line:
            with open("missed.txt","a") as missed:
                missed.write(line + '\n')

except KeyboardInterrupt:
    os.kill(multimon_ng.pid, 9)


Tadcom
Posts: 1
Joined: Sun May 11, 2014 6:02 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Sun May 11, 2014 6:06 pm

I've done everything like you all described, but I get this output:
Enabled demodulators: POCSAG512 POCSAG1200 POCSAG2400
POCSAG2400: Address: 724320 Function: 0
POCSAG2400: Address: 26267 Function: 3
POCSAG1200: Address: 1901616 Function: 1
POCSAG512: Address: 1837816 Function: 0
POCSAG512: Address: 362826 Function: 1
POCSAG512: Address: 40810 Function: 2
POCSAG1200: Address: 46824 Function: 2
POCSAG2400: Address: 821352 Function: 3 Alpha: J%
POCSAG1200: Address: 832608 Function: 2
POCSAG512: Address: 1804496 Function: 0
POCSAG512: Address: 846328 Function: 1
POCSAG2400: Address: 882016 Function: 0
POCSAG512: Address: 802632 Function: 0
POCSAG2400: Address: 1405144 Function: 3
POCSAG2400: Address: 1097648 Function: 2
POCSAG512: Address: 730385 Function: 1
POCSAG512: Address: 1637658 Function: 3 Alpha: az<EM>P<CAN>
POCSAG2400: Address: 236168 Function: 3
POCSAG2400: Address: 1991769 Function: 1
POCSAG2400: Address: 75728 Function: 0

Could you tell me what's wrong? I think that the signal is too weak... :roll:

Sonny_Jim
Posts: 45
Joined: Tue Oct 23, 2012 4:15 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Jun 05, 2014 2:35 pm

One thing you can do is plug the dongle into a PC and run an SDR program on there. Capture a wav file of what you are receiving and post it somewhere, so we can check whether it's a signal strength issue or mistuned or whatever.

rec9140
Posts: 28
Joined: Mon Sep 12, 2011 5:29 pm
Contact: Website

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Mon Sep 08, 2014 6:06 pm

russinnes wrote:Heres a small python script that will give you a "PDW" like output.. its a little nicer to read and you can easily mod the code to do what you need, either by text, capcode, etc, etc.
trying to run your code, and I get:

Code: Select all


$ ./ViewPages.py 
Traceback (most recent call last):
  File "./ViewPages.py", line 27, in <module>
    message = line.split('Alpha:   ')[1].strip().rstrip('<ETB>').strip()
IndexError: list index out of range

OR  ** AFTER A CHANGE from ETB to EOT


 ./ViewPages.py 
Traceback (most recent call last):
  File "./ViewPages.py", line 27, in <module>
    message = line.split('Alpha:   ')[1].strip().rstrip('<EOT>').strip()
IndexError: list index out of range

Also with a NUL too

  File "./ViewPolkPages.py", line 27, in <module>
    message = line.split('Alpha:   ')[1].strip().rstrip('<NUL>').strip()
IndexError: list index out of range

EXAMPLE PAGE as viewed from my log file... 
POCSAG1200-: Address:    XXXXXX  Function: 0
POCSAG1200-: Numeric: 4 4]41.14.]019.3U--480U81U043-66099 40-3U.4-9629854091392-22U0494.18].[24]53U029--85027.4[8 2018870U7188633 1]07]3618482 8280.  0]0U80.7.314] 7.49.8 96298540-3-8029--8502.]017 209 462U.50950.6781]0[0[9U  2 261U85618 89697914059[U3.1409 U 3]77UU-567397]0227.7]0[03-7 860589]02.3.3-3701-3--]23U045577.9]37-905.2U85 850.2.3561U818.5023. [--60-0980-U18069U71 07[291 264305 66.U95]4703 1100
POCSAG1200-: Alpha: DISPATCH:67B01, SMALL OUTSIDE FIRE, XXXXX/HWY XX, NRG,  <0/ 43888>, BBQ PLACE ON NORTHSIDE OF XX, TC8, 2225A, mappage,XXXX, Fire ProQA recommends dispatch at this time, Units:BR211, EN211 - From CDP7 09/08/2014 13:39:08<EOT><NUL>

Full code with modified rtl/multimon line:

#!/usr/bin/python

import time
import sys
import subprocess
import os

def curtime():
    return time.strftime("%H:%M:%S %Y-%m-%d")

with open('error.txt','a') as file:
    file.write(('#' * 20) + '\n' + curtime() + '\n')

multimon_ng = subprocess.Popen("rtl_fm -l 32 -g 42.0 -F 0 -E dc -p -111 -M fm -f 1xx.xM -s 22050 |multimon-ng -f alpha -a POCSAG1200 -t raw -",
                               #stdin=rtl_fm.stdout,
                               stdout=subprocess.PIPE,
                               stderr=open('error.txt','a'),
                               shell=True)

try:
    while True:
        line = multimon_ng.stdout.readline()
        multimon_ng.poll()
        if line.__contains__("Alpha:"):    # filter out only the alpha
            if line.startswith('POCSAG'):
                address = line[22:28].replace(" ", "").zfill(7)
                message = line.split('Alpha:   ')[1].strip().rstrip('<EOT>').strip()
                output=(address+' '+curtime()+' '+ message+'\n')
                print address, curtime(), message
                with open('pocsag.txt','a') as f:
                    f.write(output)
        if not "Alpha:" in line:
            with open("missed.txt","a") as missed:
                missed.write(line + '\n')

except KeyboardInterrupt:
    os.kill(multimon_ng.pid, 9)
Using just rtl_fm & multimon-ng and tail'ng the output of a log file is 100%... Would like to format things and process based on capcode/address// etc....

Any ideas on the error???

User avatar
carl_retrotext
Posts: 80
Joined: Sun May 06, 2012 1:05 pm
Location: essex
Contact: Website

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Wed Oct 15, 2014 3:31 pm

This is a great project, Is there any chance of FLEX being added to multimoNG? implementing jessie and sdr radio seems to be a bit of over kill.

rec9140
Posts: 28
Joined: Mon Sep 12, 2011 5:29 pm
Contact: Website

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Wed Oct 15, 2014 7:30 pm

carl_retrotext wrote:This is a great project, Is there any chance of FLEX being added to multimoNG?
Please, pretty, please, with a cherry on top for FLEX... I am DESPERATE for FLEX in a simple CLI based setup.


PLEEEEEEEEEEEEAAAAAAAASSSSSSSSSSSSEEEEEEEEEEEEEEEEEEEEEEEE......

I am using it with POCSAG and some heavy rewrite from a post here to get things to log, SMTP alerts, MySQL logging for further data analysis etc...

And FLEX would allow me to cover a few more bases.

PLEEEEEEEEEEEEEEASSSSSSSSSSSEEEEEEEEEEE.. :) :) :) ;) ;)
:mrgreen: :mrgreen: :mrgreen:

User avatar
carl_retrotext
Posts: 80
Joined: Sun May 06, 2012 1:05 pm
Location: essex
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Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Oct 16, 2014 7:59 am

:) Flex is the majority of TX , they seem to take alternate bursts on the same frequency, so no re-tune would be required.

Sonny_Jim
Posts: 45
Joined: Tue Oct 23, 2012 4:15 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Mon Nov 03, 2014 9:32 pm

There are a few FLEX decoders for gnuradio and there's an image available that has gnuradio bundled with it:
http://garethhayes.net/gnu-radio-for-raspberry-pi/

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carl_retrotext
Posts: 80
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Location: essex
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Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Nov 13, 2014 9:18 pm

Sonny_Jim wrote:After speaking to the author of rtl_fm it appears there is a problem with the later versions that cause it to stop working with multimon-ng, which he is looking into. For now you'll have to roll back to the earlier commit I posted.

As a little bonus, here's a simple way to listen to the output of rtl_fm in a browser by using socat and sox:

Code: Select all

sudo apt-get install sox socat
 rtl_fm [parameters] | sox -traw -r24k -es -b16 -c1 - -togg - | socat -u - TCP-LISTEN:8080
If you run that then navigate to http://PI_IP_ADDRESS:8080 you should be able to hear what rtl_fm is outputting.
This has potential, thank you.

I was wondering if I could pipe the sound and save it to listen to later ,is there on I can install on the PI?

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carl_retrotext
Posts: 80
Joined: Sun May 06, 2012 1:05 pm
Location: essex
Contact: Website

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Thu Nov 13, 2014 9:18 pm

Sonny_Jim wrote:There are a few FLEX decoders for gnuradio and there's an image available that has gnuradio bundled with it:
http://garethhayes.net/gnu-radio-for-raspberry-pi/
Thanks Sonny_Jim I will check them out. ;)

dcr_inc
Posts: 7
Joined: Wed Jul 08, 2015 11:13 pm

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Mon Jul 13, 2015 2:26 pm

Hello,
Does anyone have a working image of this decoder setup?

I have been attempting to get anything working and have had, I believe, no success..

I have installed and compiled and added blacklist files and I still don't hear or see anything..

HELP !!

I would like a "simple" PDW type output and the ability to hear the paging activity on the frequency (453.600 MHz NFM)

Thanks,
Dave

wizmedic
Posts: 1
Joined: Sun Oct 18, 2015 5:24 am

Re: [HOWTO] Decoding pager transmissions with a Pi and rtl-s

Sun Oct 18, 2015 5:30 am

after alot of research and tuning these are the settings that work for me with nearly a 100% successful decode rate:
sudo rtl_fm -A fast -f 151.143M -M fm -s 22050 -g 44.5 -l 305 | multimon-ng -n -v1 -p -t raw -a POCSAG512 -a POCSAG1200 -f alpha /dev/stdin

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