OrangePi: mengoperasikan RTL-SDR

Power Supply

Tampaknya power supply akan menjadi sangat penting sekali. Charger 5V 2.1A tampaknya kurang. Kalau arus kurang, maka tidak akan kuat mengangkat RTL-SDR-nya.

Instalasi Pendukung

sudo su
apt-get update
apt-get -y install git cmake build-essential libusb-1.0 libusb-1.0-0-dev \
libpulse-dev libx11-dev libpulse-dev libx11-dev python-pkg-resources qtcreator \
libtool autoconf automake libfftw3-dev

Instalasi Driver RTL-SDR

cd ~/
git clone git://git.osmocom.org/rtl-sdr.git
cd rtl-sdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON
make
sudo make install
sudo ldconfig

Deteksi Card / Dongle

rtl_test -s 1000000 -p 5

Hasilnya

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

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5  48.0 49.6 
Exact sample rate is: 1000000.026491 Hz
[R82XX] PLL not locked!
Sampling at 1000000 S/s.
Reporting PPM error measurement every 10 seconds...
Press ^C after a few minutes.
Reading samples in async mode...
real sample rate: 1000040 current PPM: 41 cumulative PPM: 41
real sample rate: 1000026 current PPM: 27 cumulative PPM: 34
real sample rate: 1000034 current PPM: 34 cumulative PPM: 34
real sample rate: 1000033 current PPM: 34 cumulative PPM: 34
real sample rate: 1000025 current PPM: 25 cumulative PPM: 32
real sample rate: 1000015 current PPM: 16 cumulative PPM: 29
real sample rate: 1000039 current PPM: 40 cumulative PPM: 31
^CSignal caught, exiting!

User cancel, exiting...
Samples per million lost (minimum): 0

Instalasi multimonNG

cd ~/
git clone https://github.com/EliasOenal/multimonNG.git
cd multimonNG
mkdir build
cd build
qmake ../multimon-ng.pro
make
sudo make install

Decode APRS

# rtl_fm -f 144.800M -s 22050 | multimon-ng -t raw -a AFSK1200 -f alpha /dev/stdin
rtl_fm -f 144.390M -s 22050 | multimon-ng -t raw -a AFSK1200 -f alpha /dev/stdin

Akan keluar kira-kira

Found 1 device(s):

 0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
multimon-ng 1.1.5
  (C) 1996/1997 by Tom Sailer HB9JNX/AE4WA
  (C) 2012-2018 by Elias Oenal
Available demodulators: POCSAG512 POCSAG1200 POCSAG2400 FLEX EAS UFSK1200 CLIPFSK FMSFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3 HAPN4800 FSK9600 DTMF ZVEI1  ZVEI2 ZVEI3 DZVEI PZVEI EEA EIA CCIR MORSE_CW DUMPCSV X10 SCOPE
Enabled demodulators: AFSK1200
Found Rafael Micro R820T tuner
Tuner gain set to automatic.
Tuned to 144643575 Hz.
Oversampling input by: 46x.
Oversampling output by: 1x.
Buffer size: 8.08ms
Exact sample rate is: 1014300.020041 Hz
cb transfer status: 5, canceling...
Failed to submit transfer 2
Please increase your allowed usbfs buffer size with the following command:
echo 0 > /sys/module/usbcore/parameters/usbfs_memory_mb
cb transfer status: 5, canceling...
r82xx_write: i2c wr failed=-4 reg=0a len=1
rtlsdr_demod_write_reg failed with -4
rtlsdr_demod_read_reg failed with -4
rtlsdr_demod_write_reg failed with -4
rtlsdr_demod_read_reg failed with -4
rtlsdr_demod_write_reg failed with -4
rtlsdr_demod_read_reg failed with -4
rtlsdr_demod_write_reg failed with -4
rtlsdr_demod_read_reg failed with -4
rtlsdr_demod_write_reg failed with -4
rtlsdr_demod_read_reg failed with -4
rtlsdr_demod_write_reg failed with -4
rtlsdr_demod_read_reg failed with -4
rtlsdr_demod_write_reg failed with -4
rtlsdr_demod_read_reg failed with -4
WARNING: Failed to set sample rate.
Output at 22050 Hz.

Kalibrasi Drift

cd ~/
git clone https://github.com/asdil12/kalibrate-rtl.git
cd kalibrate-rtl
git checkout arm_memory
./bootstrap
./configure
make
sudo make install

Kalibrasi

kal -s GSM900
kal -c 100

Instalasi MultimonAPRS

cd ~/
git clone https://github.com/asdil12/pymultimonaprs.git
cd pymultimonaprs
chmod a+x setup.py
./setup.py build
sudo ./setup.py install

Edit

sudo nano /etc/pymultimonaprs.json

Siapkan

• Callsign
• Passcode - Passcode bisa di generate dari situs https://apps.magicbug.co.uk/passcode/index.php
• Latitude
• Longitude

Hasilnya,

{
       "callsign": "NOCALL-10"
       "passcode": "12345",
       "gateway": ["euro.aprs2.net:14580","noam.aprs2.net:14580"],
       "preferred_protocol": "any",
       "append_callsign": true,
       "source": "rtl",
       "rtl": {
               "freq": 144.390,
               "ppm": 0,
               "gain": 0,
               "offset_tuning": false,
               "device_index": 0
       },
       "alsa": {
               "device": "default"
       },
       "beacon": {
               "lat": -6.168589,
               "lng": 106.865090,
               "table": "R",
               "symbol": "&",
               "comment": "PyMultimonAPRS iGate",
               "status": {
                       "text": "Running on OrangePi with RTL dongle",
                       "file": false
               },
               "weather": false,
               "send_every": 300,
               "ambiguity": 0
       }
}

Edit init

sudo nano /etc/init.d/pymultimonaprs

#!/bin/sh
### BEGIN INIT INFO
# Provides: pymultimonaprs
# Required-Start: $all
# Required-Stop: $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: start/stop of pymultimonaprs
### END INIT INFO

case "$1" in
 start)
   sudo pymultimonaprs --syslog &
   ;;
 stop)
   sudo killall pymultimonaprs
   ;;
 *)
   echo "Usage: /etc/init.d/pymultimonaprs {start|stop}"
   exit 1
   ;;
esac

exit 0

Permission execute

sudo chmod +x /etc/init.d/pymultimonaprs

sudo update-rc.d pymultimonaprs defaults
sudo reboot

Referensi

• http://sq7mru.blogspot.com/2013/08/aprs-igate-rx-z-tunera-dvb-t.html