This example is a mono Wideband FM broadcast radio receiver. It can be used to listen to FM Broadcast stations. It uses the RTL-SDR as an SDR source, plays audio with PulseAudio, and shows two real-time plots: the demodulated FM spectrum and the L+R channel audio spectrum.
This mono Wideband FM broadcast demodulator composition is available in
LuaRadio as the
WBFMMonoDemodulator
block.
Usage: examples/rtlsdr_wbfm_mono.lua <FM radio frequency>
Running this example in a headless environment will inhibit plotting and record
audio to the WAV file wbfm_mono.wav.
Listen to 91.1 MHz:
$ ./luaradio examples/rtlsdr_wbfm_mono.lua 91.1e6
This example is a stereo Wideband FM broadcast radio receiver. It can be used to listen to FM Broadcast stations, like the mono Wideband FM example, but it also supports stereo sound. It uses the RTL-SDR as an SDR source, plays audio with PulseAudio, and shows three real-time plots: the demodulated FM spectrum, the L+R channel audio spectrum, and the L-R channel audio spectrum.
This stereo Wideband FM broadcast demodulator composition is available in
LuaRadio as the
WBFMStereoDemodulator
block.
Usage: examples/rtlsdr_wbfm_stereo.lua <FM radio frequency>
Running this example in a headless environment will inhibit plotting and record
audio to the WAV file wbfm_stereo.wav.
Listen to 91.1 MHz:
$ ./luaradio examples/rtlsdr_wbfm_stereo.lua 91.1e6
This example is a Narrowband FM radio receiver. It can be used to listen to NOAA weather radio in the US, amateur radio operators, analog police and emergency services, and more, on the VHF and UHF bands. It uses the RTL-SDR as an SDR source, plays audio with PulseAudio, and shows two real-time plots: the RF spectrum and the demodulated audio spectrum.
This NBFM demodulator composition is available in LuaRadio as the
NBFMDemodulator block.
Usage: examples/rtlsdr_nbfm.lua <frequency>
Running this example in a headless environment will inhibit plotting and record
audio to the WAV file nbfm.wav.
Listen to NOAA1, 162.400 MHz:
$ ./luaradio examples/rtlsdr_nbfm.lua 162.400e6
Additional NOAA weather radio station frequencies: 162.400 MHz (NOAA1),
162.425 MHz (NOAA2), 162.450 MHz (NOAA3), 162.475 MHz (NOAA4),
162.500 MHz (NOAA5), 162.525 MHz (NOAA6), 162.550 MHz (NOAA7).
This example is an AX.25 packet radio receiver for Narrowband FM, Bell 202 AFSK modulated transmissions on the VHF and UHF bands. It can be used to receive APRS and other AX.25-based data transmissions. It uses the RTL-SDR as an SDR source, writes decoded AX.25 frames in JSON to standard out, and shows two real-time plots: the RF spectrum and the demodulated bitstream.
This AX.25 receiver composition is available in LuaRadio as the
AX25Receiver block.
Usage: examples/rtlsdr_ax25.lua <frequency>
Running this example in a headless environment will inhibit plotting.
Receive APRS on 144.390 MHz, the North American VHF APRS frequency:
$ ./luaradio examples/rtlsdr_ax25.lua 144.390e6
{"payload":"@030151z3845.28N/12035.52W_000/000g000t054r000p000P000h70b10136/ {UIV32N}\r","control":3,"addresses":[{"ssid":48,"callsign":"APU25N"},{"ssid":112,"callsign":"K6GER "},{"ssid":112,"callsign":"WARD "},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE2 "}],"pid":240}
{"payload":"`2-1l 5k/'\"3r}GTARC 146.805 & 406.600 both (-) PL 100|)2%n']|!w?;!|3","control":3,"addresses":[{"ssid":48,"callsign":"S8QXXW"},{"ssid":57,"callsign":"KJ6PCW"},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE1 "},{"ssid":49,"callsign":"WIDE2 "}],"pid":240}
{"payload":"`2-1l 5k/'\"3r}GTARC 146.805 & 406.600 both (-) PL 100|)2%n']|!w?;!|3","control":3,"addresses":[{"ssid":48,"callsign":"S8QXXW"},{"ssid":57,"callsign":"KJ6PCW"},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE1 "},{"ssid":112,"callsign":"BKELEY"},{"ssid":112,"callsign":"WIDE2 "}],"pid":240}
{"payload":"@094656h3754.16NI12216.92W&(Time 0:00:00)PHG3340/Kensington, CA (I-GATE) */A=000404","control":3,"addresses":[{"ssid":112,"callsign":"APWW10"},{"ssid":53,"callsign":"KC6SSM"},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE1 "},{"ssid":49,"callsign":"WIDE2 "}],"pid":240}
{"payload":"!3956.16N/12138.86W# 13.6V 62F ","control":3,"addresses":[{"ssid":112,"callsign":"APOT30"},{"ssid":115,"callsign":"W6SCR "},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE1 "}],"pid":240}
{"payload":"`1N8l#K>/`\"4{}443.575MHz T110 +500_%\r","control":3,"addresses":[{"ssid":48,"callsign":"SWRSYY"},{"ssid":121,"callsign":"KE6STH"},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE1 "},{"ssid":49,"callsign":"WIDE2 "}],"pid":240}
{"payload":"`1N8l#K>/`\"4{}443.575MHz T110 +500_%\r","control":3,"addresses":[{"ssid":48,"callsign":"SWRSYY"},{"ssid":121,"callsign":"KE6STH"},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE1 "},{"ssid":112,"callsign":"BKELEY"},{"ssid":112,"callsign":"WIDE2 "}],"pid":240}
{"payload":"@270947z3715.26N/12153.30W#Digi & Igate / [email protected]","control":3,"addresses":[{"ssid":48,"callsign":"APMI06"},{"ssid":48,"callsign":"K6RPT "},{"ssid":115,"callsign":"N6ZX "},{"ssid":49,"callsign":"WIDE2 "}],"pid":240}
{"payload":"@270947z3715.26N/12153.30W#Digi & Igate / [email protected]","control":3,"addresses":[{"ssid":48,"callsign":"APMI06"},{"ssid":48,"callsign":"K6RPT "},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"BKELEY"},{"ssid":112,"callsign":"WIDE2 "}],"pid":240}
{"payload":"!4001.07N/12122.89W# 12.8V 44F K6FHL Highlakes Fillin W1","control":3,"addresses":[{"ssid":112,"callsign":"APOT30"},{"ssid":112,"callsign":"HILAKE"},{"ssid":115,"callsign":"N6ZX "},{"ssid":112,"callsign":"WIDE2 "}],"pid":240}
...
This example is a POCSAG receiver. It can be used to receive pager messages dispatched by hospital, fire, emergency, and police services, as well as some businesses. POCSAG messages are transmitted in plaintext. It uses the RTL-SDR as an SDR source, writes decoded POCSAG messages in JSON to standard out, and shows two real-time plots: the RF spectrum and the demodulated bitstream.
This POCSAG receiver composition is available in LuaRadio as the
POCSAGReceiver block.
Usage: examples/rtlsdr_pocsag.lua <frequency>
Running this example in a headless environment will inhibit plotting.
You may need to explore your local spectrum with a waterfall receiver to find a POCSAG transmitter.
Receive POCSAG on 152.240 MHz:
$ ./luaradio examples/rtlsdr_pocsag.lua 152.240e6
{"address":1234567,"func":2,"alphanumeric":"THIS IS A TEST PERIODIC PAGE SEQUENTIAL NUMBER 1973"}
{"address":234567,"func":2,"alphanumeric":"THIS IS A TEST PERIODIC PAGE SEQUENTIAL NUMBER 1973"}
{"address":1234567,"func":2,"alphanumeric":"THIS IS A TEST PERIODIC PAGE SEQUENTIAL NUMBER 1974"}
{"address":234567,"func":2,"alphanumeric":"THIS IS A TEST PERIODIC PAGE SEQUENTIAL NUMBER 1974"}
{"address":1234567,"func":2,"alphanumeric":"THIS IS A TEST PERIODIC PAGE SEQUENTIAL NUMBER 1975"}
{"address":234567,"func":2,"alphanumeric":"THIS IS A TEST PERIODIC PAGE SEQUENTIAL NUMBER 1975"}
...
This example is a Radio Data System (RDS) receiver. RDS is a digital protocol used by FM Broadcast radio stations to transmit metadata about the station and its programming. This protocol is most commonly known for providing station and song text information with "RadioText" messages. This examples uses the RTL-SDR as an SDR source, writes decoded RDS frames in JSON to standard out, and shows three real-time plots: the demodulated FM spectrum, the BPSK spectrum, and the BPSK constellation.
This example can be used with FM Broadcast radio stations, like the
rtlsdr_wbfm_mono.lua and rtlsdr_wbfm_stereo.lua examples.
This RDS receiver composition is available in LuaRadio as the
RDSReceiver block.
Usage: examples/rtlsdr_rds.lua <FM radio frequency>
Running this example in a headless environment will inhibit plotting.
Receive RDS on 88.5 MHz:
$ ./luaradio examples/rtlsdr_rds.lua 88.5e6
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":" ","di_position":0,"text_address":3,"ms_code":1,"di_value":1,"af_code":[6,8],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":2,"group_version":0,"pty_code":22},"data":{"type":"radiotext","text_data":"Nort","text_address":6,"ab_flag":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":"KQ","di_position":3,"text_address":0,"ms_code":1,"di_value":0,"af_code":[227,10],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":2,"group_version":0,"pty_code":22},"data":{"type":"radiotext","text_data":"hern","text_address":7,"ab_flag":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":"ED","di_position":2,"text_address":1,"ms_code":1,"di_value":0,"af_code":[6,8],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":1,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,4805,160,2002]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":" ","di_position":1,"text_address":2,"ms_code":1,"di_value":0,"af_code":[227,10],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":8,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,33494,24158,16374]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":" ","di_position":0,"text_address":3,"ms_code":1,"di_value":1,"af_code":[6,8],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":2,"group_version":0,"pty_code":22},"data":{"type":"radiotext","text_data":" Cal","text_address":8,"ab_flag":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":8,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,33494,24158,16374]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":"KQ","di_position":3,"text_address":0,"ms_code":1,"di_value":0,"af_code":[227,10],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":3,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,13008,16833,52550]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":"ED","di_position":2,"text_address":1,"ms_code":1,"di_value":0,"af_code":[6,8],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":8,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,33494,24158,16374]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":" ","di_position":1,"text_address":2,"ms_code":1,"di_value":0,"af_code":[227,10],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":4,"group_version":0,"pty_code":22},"data":{"type":"datetime","time":{"offset":-7,"hour":9,"minute":57},"date":{"day":27,"year":2016,"month":5}}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":8,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,33494,28270,16202]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":" ","di_position":0,"text_address":3,"ms_code":1,"di_value":1,"af_code":[6,8],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":2,"group_version":0,"pty_code":22},"data":{"type":"radiotext","text_data":"ifor","text_address":9,"ab_flag":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":"KQ","di_position":3,"text_address":0,"ms_code":1,"di_value":0,"af_code":[227,10],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":8,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,33494,28270,16202]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":"ED","di_position":2,"text_address":1,"ms_code":1,"di_value":0,"af_code":[6,8],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":" ","di_position":1,"text_address":2,"ms_code":1,"di_value":0,"af_code":[227,10],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":8,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,33494,28270,16202]}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":0,"group_version":0,"pty_code":22},"data":{"text_data":" ","di_position":0,"text_address":3,"ms_code":1,"di_value":1,"af_code":[6,8],"type":"basictuning","ta_code":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":2,"group_version":0,"pty_code":22},"data":{"type":"radiotext","text_data":"nia ","text_address":10,"ab_flag":0}}
{"header":{"pi_code":15019,"tp_code":0,"group_code":1,"group_version":0,"pty_code":22},"data":{"type":"raw","frame":[15019,4806,160,2002]}}
...
This example is an AM radio receiver, implemented with an envelope detector. It can be used to listen to broadcast stations on the MF (AM Broadcast) and HF (Shortwave Broadcast) bands, as well as aviation communication on the VHF airband. It uses the RTL-SDR as an SDR source, plays audio with PulseAudio, and shows two real-time plots: the RF spectrum and the demodulated audio spectrum.
This example requires an RF upconverter to listen to stations on the HF and MF bands with the RTL-SDR.
This AM envelope demodulator composition is available in LuaRadio as the
AMEnvelopeDemodulator
block.
Usage: examples/rtlsdr_am_envelope.lua <frequency>
Running this example in a headless environment will inhibit plotting and record
audio to the WAV file am_envelope.wav.
Listen to WWV at 5 MHz (with a 125 MHz upconverter):
$ ./luaradio examples/rtlsdr_am_envelope.lua 130e6
Listen to an AM radio station at 560 kHz (with a 125 MHz upconverter):
$ ./luaradio examples/rtlsdr_am_envelope.lua 125.560e6
This example is an AM radio receiver, implemented with a phase-locked loop for synchronous demodulation. It can be used to listen to broadcast stations on the MF (AM Broadcast) and HF (Shortwave Broadcast) bands, as well as aviation communication on the VHF airband. It uses the RTL-SDR as an SDR source, plays audio with PulseAudio, and shows two real-time plots: the RF spectrum and the demodulated audio spectrum.
This example requires an RF upconverter to listen to stations on the HF and MF bands with the RTL-SDR.
This AM synchronous demodulator composition is available in LuaRadio as the
AMSynchronousDemodulator
block.
Usage: examples/rtlsdr_am_synchronous.lua <frequency>
Running this example in a headless environment will inhibit plotting and record
audio to the WAV file am_synchronous.wav.
Listen to WWV at 5 MHz (with a 125 MHz upconverter):
$ ./luaradio examples/rtlsdr_am_synchronous.lua 130e6
Listen to an AM radio station at 560 kHz (with a 125 MHz upconverter):
$ ./luaradio examples/rtlsdr_am_synchronous.lua 125.560e6
This example is a Single-Sideband (SSB) AM radio receiver. SSB is commonly used by amateur radio operators on the HF band, and sometimes on the VHF and UHF bands, for voice and digital (modulated in the audio) communication. This example uses the RTL-SDR as an SDR source, plays audio with PulseAudio, and shows two real-time plots: the RF spectrum and the demodulated audio spectrum.
This example requires an RF upconverter to listen to stations on the HF and MF bands with the RTL-SDR.
This single-sideband demodulator composition is available in LuaRadio as the
SSBDemodulator block.
Usage: examples/rtlsdr_ssb.lua <frequency> <sideband>
Running this example in a headless environment will inhibit plotting and record
audio to the WAV file ssb.wav.
Listen to 3.745 MHz (with a 125 MHz upconverter), lower sideband:
$ ./luaradio examples/rtlsdr_ssb.lua 128.745e6 lsb
This example is a file-based
Single-Sideband
(SSB) modulator. It takes a single channel WAV file audio input, and produces a
binary IQ file (f32le format) output with the single-sideband modulated
audio. This example doesn't use the RTL-SDR at all, but instead demonstrates
how you can build file-based command-line utilities with modulation,
demodulation, decoding, file conversion, etc. flow graphs that run to
completion.
This single-sideband modulator composition is available in LuaRadio as the
SSBModulator block.
Usage: examples/wavfile_ssb_modulator.lua <WAV file in> <IQ f32le file out> <bandwidth> <sideband>
Modulate test.wav into test.iq, with 3 kHz bandwidth and lower sideband:
$ ./luaradio examples/wavfile_ssb_modulator.lua test.wav test.iq 3e3 lsb
This example is an IQ file format converter. It converts the binary encoding of IQ files from one format, e.g. signed 8-bit, to another, e.g. 32-bit float little endian. This example doesn't use the RTL-SDR at all, but instead demonstrates how you can build file-based command-line utilities with modulation, demodulation, decoding, file conversion, etc. flow graphs that run to completion.
Usage: examples/iqfile_converter.lua <input IQ file> <input format> <output IQ file> <output format>
Supported formats:
s8, u8,
u16le, u16be, s16le, s16be,
u32le, u32be, s32le, s32be,
f32le, f32be, f64le, f64be
Convert test.s8.iq, with signed 8-bit samples, into test.f32le.iq, with
32-bit float little endian samples:
$ ./luaradio examples/iqfile_converter.lua test.s8.iq s8 test.f32le.iq f32le
$ du -b test.s8.iq
10236 test.s8.iq
$ du -b test.f32le.iq
40944 test.f32le.iq
$