osmocom-sdr January 2014

osmocom-sdr@lists.osmocom.org

39 participants
47 discussions

what to see
by 393775602 22 Jan '14

22 Jan '14

Hi， i have just transmited the rtl-sdr code into android using NDK，and i start the rtl-sdr and set the fequecny,samp_rate and so on. Finally i get the output from rtl and write it into a txt file. Then the problem came, i open the txt and find it a mess, does the output decode in utf-8 or something else,can anyone give me a look to see what output is like Thanks a lot chenzujie

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Use multi-dongles to speedup identifying all available/detectable GSM downlink broadcasting carrier
by Jiao Xianjun 22 Jan '14

22 Jan '14

Hi, As a "side product" of this thread: "How to get IQ samples from multiple rtl-sdr dongles in a synchronized manner",A scanning tool is released for identifying all available/detectable GSM broadcasting carrier around you quickly. You can find it here: http://www.mathworks.com/matlabcentral/fileexchange/45152-rtl-sdr-multi-don… or https://github.com/JiaoXianjun/multi-rtl-sdr-calibration By using 3 dongles, we can identify all available/detectable GSM broadcasting carrier in the whole PGSM band downlink 935~960MHz in 30s (my intel i7 12-core station) instead of 80s (only one dongles). The original purpose of project multi-rtl-sdr-calibration is that calibrating multiple dongles by the common GSM source. So the first thing need to do is that finding out where is the strongest GSM signal in the air. This script (multi_rtl_sdr_gsm_FCCH_scanner.m) can identify GSM downlink broadcasting carrier by detecting successive multiple FCCH bursts of all possible carrier in a band you specify, such as PGSM downlink 935~960MHz. I learn knowledge of GSM frame structure from here: http://www.sharetechnote.com/html/FrameStructure_GSM.html After the script is run, quality metrics of detected FCCH channel per frequency will be displayed: SNR and number of detected FCCH burst (num of hits). Note: for speedup detection algorithm, a large decimation ratio is used, thus shown SNR may be lower than actual SNR. But it is enough to help us idendify which frequency is best. README is also pasted here: Multiple rtl-sdr(rtl_tcp) dongles based GSM FCCH scanner. ( putaoshu(a)gmail.com; putaoshu(a)msn.com) multi_rtl_sdr_gsm_FCCH_scanner.m Have multiple dongles run concurrently to speedup detecting FCCH(Frequency correction channel) burst in wide GSM band by scanning different sub-band with different dongle. This is a sub script of project: https://github.com/JiaoXianjun/multi-rtl-sdr-calibration ------------Purpose------------ The original purpose of project multi-rtl-sdr-calibration is that calibrating multiple dongles by the common GSM source. So the first thing need to do is that finding out where is the strongest GSM signal in the air. This script can identify GSM downlink broadcasting carrier by detecting successive multiple FCCH burst. I learn knowledge of GSM frame structure from here: http://www.sharetechnote.com/html/FrameStructure_GSM.html After the script is run, quality metrics of detected FCCH channel will be displayed: SNR and number of detected FCCH burst (num of hits). Note: for speedup detection algorithm, a large decimation ratio is used, thus shown SNR may be lower than actual SNR. But it is enough to help us idendify which frequency is best. -------------Usage------------- 1. Assume that you have installed rtl-sdr (http://sdr.osmocom.org/trac/wiki/rtl-sdr) and have those native utilities run correctly already. For example, you have multiple dongles, please run multiple rtl_tcp in multiple shell respectively as: rtl_tcp -p 1234 -d 0 rtl_tcp -p 1235 -d 1 rtl_tcp -p 1236 -d 2 ... 2. Then run multi_rtl_sdr_gsm_FCCH_scanner.m in MATLAB. ATTENTION! In some computer, each time before you run script, maybe you need to terminate multiple rtl_tcp and re-launch them again. ATTENTION! Please reduce number of inspected points by reducing frequency range, if your computer hasn't enough memory installed. Because all sigals are stored firstly before processing. Change following parameters in the script as you need: num_dongle = 1; % number of dongles you installed start_freq = 935e6; end_freq = 960e6; freq_step = 0.2e6; % GSM channel spacing gain = 0; ... Some key parameters: % how long signal we try to find multiple FCCH bursts in num_frame = 64; % roughly speaking, there are 1 FCCH burst per 10 frames, but 50 frames plus 1 idle frame construct one multiframe FCCH_coarse_position.m th = 10; % Peak to average threshold of detecting FCCH in moving averaging SNR(estimated by FFT) stream. max_offset = 5; % +/- range of predicted next postion of FCCH burst. ------------Algorithm------------ Because FCCH actually is a period of CW signal, we can use FFT to see if there is sharp peak in frequency domain. For the first FCCH detection, a continuous moving FFT is performed. After the first FCCH is hit, the following FCCH will be only detected at predicted position (+/- small range) according to GSM frame structure. At least 3 successive FCCH need to be detected for we to ensure one donwlink broadcasting carrier is there. See details in FCCH_coarse_position.m.

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[omri@iluz.net: Sniffing and decoding NRF24L01+ and Bluetooth LE packets using RTL-SDR]
by Harald Welte 22 Jan '14

22 Jan '14

Dear all, with the permission of the original poster, I hereby forward a message from Omri regarding his use of rtl-sdr to sniff and decode NRF24L01+ and Bluetooth LE packets. I have no involvement in the project, I'm just passing on the mail, thats' all ;) Regards, -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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sdrangelove: Allow to select build type on command line
by bon＠elektron.ikp.physik.tu-darmstadt.de 20 Jan '14

20 Jan '14

-- Uwe Bonnes bon(a)elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

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cmake: Allow to choose build type on command line.
by Uwe Bonnes 20 Jan '14

20 Jan '14

--- CMakeLists.txt | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/CMakeLists.txt b/CMakeLists.txt index ab899f2..9a6a2f1 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -3,9 +3,12 @@ list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/Modules) project(sdrangelove) -set(CMAKE_BUILD_TYPE "Release") +#set(CMAKE_BUILD_TYPE "Release") #set(CMAKE_BUILD_TYPE "ReleaseWithDebugInfo") #set(CMAKE_BUILD_TYPE "Debug") +if (NOT DEFINED CMAKE_BUILD_TYPE) + set(CMAKE_BUILD_TYPE "Release") +endif() set(QT_USE_QTOPENGL TRUE) set(CMAKE_AUTOMOC ON) -- 1.8.4

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python rtlsdr for android ?
by william hatch 19 Jan '14

19 Jan '14

I have been trying to install pyrtlsdr from https://github.com/roger-/pyrtlsdr using the librtlsdr shared libraries from https://github.com/keesj/android-rtlsdr . So far the python code installed under /mnt/sdcard/sl4a/scripts is unable to find the librtlsdr shared libraries installed in /data/data/local with that location appended to sys.path. My objective is to access and control the USB SDR tuner directly from my python code without relying on the TCP server. Any help or hints welcome.

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Elonics 4000 bandpass
by Nikos Balkanas 18 Jan '14

18 Jan '14

Hi, I would like to use my E4k dongle for wider spectrum analysis. Currently the tuner is very specific to a frequency. Is there a way to widen its bandpass filter? I have noticed some filters in src/tuner_e4k.c: Mixer filter, IF RC filter and IF channel filter. Are they of any use? Is there a librtlsdr API? TIA, Nikos

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E4K tuner blues
by Nikos Balkanas 17 Jan '14

17 Jan '14

I need to manipulate the tuners bandpass behavior. I have exported 2 more functions from librtlsdr, rtlsdr_set_filter_bw and rtlsdr_get_filter_bw and change the channel filter. However, when I use them I get libusb error(-22) **UNKNOWN ERROR**. I have tried bracketing the call with start/stop i2c repeater and disable/enable channel to no avail :-( It errs both when setting filter to 5.5 Mhz (max) and to 2.1 Mhz (min). What is going on? What other context should I provide for it to work? TIA, Nikos

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Bounce action notification
by mailman＠lists.osmocom.org 17 Jan '14

17 Jan '14

This is a Mailman mailing list bounce action notice: List: osmocom-sdr Member: benjamin(a)southpole.se Action: Subscription disabled. Reason: Excessive or fatal bounces. The triggering bounce notice is attached below. Questions? Contact the Mailman site administrator at mailman(a)lists.osmocom.org.

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Use multi-dongles to speedup scanner
by Jiao Xianjun 17 Jan '14

17 Jan '14

Hi, As a "side product" of this thread: "How to get IQ samples from multiple rtl-sdr dongles in a synchronized manner",A Matlab script is released. http://www.mathworks.com/matlabcentral/fileexchange/45024-rtl-sdr-multi-don… or https://github.com/JiaoXianjun/multi-rtl-sdr-calibration The script can use multiple dongles to do scanning, and get significant speedup compared to single dongle. (You can check reported time cost by running the script with different number of dongles) Another script uses multiple dongles to scan the same band, and combine those results together incoherently. I admit that before calibrating multiple dongles, the significant is limited. Just for FUN. README is also pasted here: Multiple rtl-sdr(rtl_tcp) dongles based Matlab frequency scanner. 1. multi_rtl_sdr_split_scanner.m Have multiple dongles run concurrently to speedup scanning wide band by scanning different sub-band with different dongle. 2. multi_rtl_sdr_diversity_scanner.m All dongles scan the same band, and then results from different dongles are combined incoherently. ------------Usage------------ 1. Assume that you have installed rtl-sdr (http://sdr.osmocom.org/trac/wiki/rtl-sdr) and have those native utilities run correctly already. For example, you have multiple dongles, please run multiple rtl_tcp in multiple shell respectively as: rtl_tcp -p 1234 -d 0 rtl_tcp -p 1235 -d 1 rtl_tcp -p 1236 -d 3 ... 2. Then run script multi_rtl_sdr_split_scanner.m or multi_rtl_sdr_diversity_scanner.m in MATLAB. ATTENTION! In some computer, each time before you run script, maybe you need to terminate multiple rtl_tcp and re-launch them again. Change following parameters in the script as you need: num_dongle = 2; start_freq = 935e6; end_freq = 960e6; freq_step = 0.05e6; observe_time = 0.1; gain = 0; sample_rate = 2.048e6; ... ------------Algorithm------------ Use high sampling rate for each frequency point. Then Auto generated narrow FIR is used to suppress noise and extract signal. At last, power of signal at each frequency is estimated and spectrum of all frequencies is generated. BR Jiao Xianjun

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osmocom-sdr January 2014