Difference between revisions of "SDR"
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airspy_rx -r /dev/stdout -f 100 -a 0 | \ |
airspy_rx -r /dev/stdout -f 100 -a 0 | \ |
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baudline -stdin -quadrature -channels 2 -flipcomplex -samplerate 10000000 -memory 256 |
baudline -stdin -quadrature -channels 2 -flipcomplex -samplerate 10000000 -memory 256 |
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+ | |||
+ | airspy_rx -r /dev/stdout -f 100 -a 1 | \ |
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+ | baudline -stdin -quadrature -channels 2 -flipcomplex -samplerate 2500000 -memory 256 |
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+ | |||
====After demodulation with GQRX==== |
====After demodulation with GQRX==== |
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In GQRX, choose to stream audio through UDP (icon on left of recording button) |
In GQRX, choose to stream audio through UDP (icon on left of recording button) |
Revision as of 23:07, 4 June 2015
Hardware
HackRF
- 1MHz - 6GHz, RX/TX half-duplex, BW 20MHz, ADC/DAC 8bit
- https://github.com/mossmann/hackrf/wiki
- Bias-T supply can deliver 3.3V 50mA
- BW & filtering: https://github.com/mossmann/hackrf/wiki/Tips-and-Tricks
- FW flashing
$ hackrf_info Found HackRF board. Board ID Number: 2 (HackRF One) Firmware Version: 2014.08.1 Part ID Number: 0xa000cb3c 0x0067434c Serial Number: 0x00000000 0x00000000 0x15d463dc 0x383f8125
Airspy
- 24MHz - 1.750GHz, RX, BW 10MHz (9MHz alias free), ADC 12bit (10.4 ENOB)
- Bias-T supply can deliver 4.5V
- FW flashing
$ airspy_info Found AirSpy board 1 Board ID Number: 0 (AIRSPY) Firmware Version: AirSpy NOS v1.0.0-rc5-0-g648c14f 2015-05-20 Part ID Number: 0x6906002B 0x00000030 Serial Number: 0x618C63C82F7424A7 Supported sample rates: 10.000000 MSPS 2.500000 MSPS Close board 1
RTL-SDR
- ~25MHz - 2GHz, RX, BW 2.4-2.8MHz, ADC 8bit
- Mine: 52-2212 MHz with gap @ 1107-1241 MHz
LNA: Low Noise Amplifiers
- LNA4ALL
- 28-2500MHz, gain about 22dB from 28MHz to 600MHz then gain drops to ~16dB @ 1400MHz and ~11dB @ 2500MHz, 0.75dB NF @ 1 GHz and 0.98dB NF @ 2 GHz
- 6-9 V, 55-65 mA (5V if regulator bridged)
- can be powered by HackRF or Airspy if modified, 10uH SMD on OUT and regulator bridged (because we deliver <5V) or bridged by 100mA fuse, just in case.
- LNA4HF
- 150kHz - 30MHz, gain 18-20 dB, NF 1-2 dB
- 6-9 V, 18 mA (5V if regulator bridged)
- up to 2GHz if low-pass filter removed
- Better to position LNA near antenna than near receiver, more useful info here
Antennas
ANT500
- 50 ohms, 75 MHz - 1 GHz, 20cm - 88cm
Software
- https://github.com/mossmann/hackrf/wiki/Operating-System-Tips -> PyBOMBS
- HackRF specific: https://github.com/mossmann/hackrf/wiki/Software-with-HackRF-Support
Reverse engineering
Info
Generic
GQRX
Baudline
With hackrf
Add offset to avoid DC, e.g. to monitor 440MHz -> 442MHz
E.g. somewhere around 100MHz @ 8MHz:
hackrf_transfer -r /dev/stdout -f 100000000 -s 8000000 | \ baudline -stdin -quadrature -channels 2 -flipcomplex -format u8 -samplerate 8000000 -memory 256
With airspy
Freq is given in MHz, sample rate is given by fw offset: -a 0 = 10M, -a 1 = 2.5M
By default airspy_rx & baudline work with 16bit LSB samples
airspy_rx -r /dev/stdout -f 100 -a 0 | \ baudline -stdin -quadrature -channels 2 -flipcomplex -samplerate 10000000 -memory 256
airspy_rx -r /dev/stdout -f 100 -a 1 | \ baudline -stdin -quadrature -channels 2 -flipcomplex -samplerate 2500000 -memory 256
After demodulation with GQRX
In GQRX, choose to stream audio through UDP (icon on left of recording button)
nc -l -u -p 7355 | \ baudline -stdin -samplerate 48000
Tuning
- input / color aperture
- zoom: alt+arrows
- Hz zoom: require larger FFT (process / transform size), trade-off with temporal resolution
27MHz RC
87MHz to 108MHz FM band
315MHz car keyfob
480MHz interferences
Stripes around 480MHz are because of poorly shielded USB cable
524 to 542 MHz wireless microphones
- http://www.sharebrained.com/2013/06/15/wireless-microphones-and-hackrf/
- microphone_shure.grc FM demodulator