Page 1 of 1

Missing messages when decoding pager

Posted: Fri Mar 20, 2015 5:32 pm
by VK3MP
Hi all,
I am decoding paging messages using rtl_fm and multimon-ng and I regularly miss messages.
I have a good antenna and strong signal, and have even replicated my decoder, running both at the same time, and they both miss the same messages.
Here are my command line options on a Raspberry pi 2 and RTL Dongle:

rtl_fm -s 22050 -f 148.9125M - | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 /dev/stdin -f alpha

This is the output when it first starts:

Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
multimon-ng (C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
(C) 2012-2014 by Elias Oenal
available demodulators: POCSAG512 POCSAG1200 POCSAG2400 EAS UFSK1200 CLIPFSK FMSFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1 ZVEI2 ZVEI3 DZVEI
PZVEI EEA EIA CCIR MORSE_CW DUMPCSV SCOPE
Found Rafael Micro R820T tuner
Tuner gain set to automatic.
Tuned to 149166075 Hz.
Oversampling input by: 46x.
Oversampling output by: 1x.
Buffer size: 8.08ms
Exact sample rate is: 1014300.020041 Hz
Sampling at 1014300 S/s.
Output at 22050 Hz.


I am not sure if it is a decoding issue, or just interference, any ideas most welcome.
Brett.

Missing messages when decoding pager

Posted: Fri Mar 20, 2015 6:51 pm
by Phantom
Welcome to the forum
Be sure to share your setup with the group, as a lot of people would be interested to learn about decoding and RPi, especially ways to get it up and running from a barebones image and Pi

Re: Missing messages when decoding pager

Posted: Fri Mar 20, 2015 7:29 pm
by VK3MP
Phantom wrote:Welcome to the forum
Be sure to share your setup with the group, as a lot of people would be interested to learn about decoding and RPi, especially ways to get it up and running from a barebones image and Pi
Thanks for the welcome, and sure here is what I used to set them up, very straightforward:
http://www.raspberrypi.org/forums/viewtopic.php?t=45142
Brett.