osmocom-sdr November 2014

osmocom-sdr@lists.osmocom.org

8 participants
7 discussions

Question about rtlsdr read_sync()
by Allen Welkie 24 Nov '14

24 Nov '14

Just trying to figure out how to use the rtlsdr_read_sync() function, and I'm not understanding just by reading the source. Am I supposed to call this function continuously in a loop in a thread separate from the sample processing, or can I do some processing in between calls to rtlsdr_read_sync()? In other words, are the samples being buffered on the rtlsdr device in between calls? If so, what's the size of that buffer? Also, what functions need to be called before I can use the read_sync or read_async functions? I'm calling rtlsdr_open, rtlsdr_set_center_freq, and rtlsdr_set_sample_rate before calling rtlsdr_read_sync, but I'm not getting any samples (and subsequent calls to rtlsdr_read_sync or read_async fail, e.g. from running the rtlsdr_fm program). Thanks, Allen

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Segmentation Fault on OsmoSDR-Source
by staufenbiel 19 Nov '14

19 Nov '14

Hi, I'm running a RTL-SDR over a Raspberry Pi. On my old machine everthing worked fine. But now I had to move to another machine and I'm getting this output everytime I start my programm: linux; GNU C++ version 4.7.2; Boost_104900; UHD_003.007.002-0-unknown Warning: failed to XInitThreads() Gtk-Message: Failed to load module "canberra-gtk-module" Using Volk machine: avx_64_mmx_orc gr-osmosdr 0.1.3 (0.1.3) gnuradio 3.7.5 built-in source types: file osmosdr fcd rtl rtl_tcp uhd miri hackrf bladerf rfspace airspy Segmentation fault I have installed GNU Radio with the build-gnuradio script. So everthing should be installed correctly. Thank you for your help! Björn

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sdriq on mac
by Alexander Tudor 18 Nov '14

18 Nov '14

Hi, I have tried to use gqrx with an RFSPACE sdriq using the gr-osmosdr. The experiment failed on both 10.7.5 and 10.9.5 despite following the ftdi site instructions for either OS. I have installed all s/w via mac ports. D2XX is installed in /usr/local/lib and, according to the suggestion of a person from Ettus, tried to set DYLD_INSERT_LIBRARIES=/usr/local/lib/libftd2xx.1.2.2.dylib gxrz. All to no avail. When I run gqrx I get: and if I edit the settings, I get: But there is not /dev/ttyUSB0 nor do I know why a device is required if there is direct access (I suppose via libusb?). System profiler clearly show the device: Could anybody tell me what is the prescribed way of achieving what I am trying, or a way of debugging what is wrong? Thank you, Alex

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Complex FIR and Stereo support for rtl_fm
by Miroslav Slugeň 12 Nov '14

12 Nov '14

Hi again, I am working on my own SDR project for Stereo FM radio support, but i would like to also improve quality for rtl_fm application, i made unoficial patch to add: Complex FIR - to filter strong signals close to wanted signal Real FIR - to filter pilot from FM Stereo FIR Stereo Deemphasis AGC support - it can give better resolution of IQ data Some other improvments in FM radio code. All FIR filters has 3 possible variants, simple, LUT, SSE2 instricts, of course SSE is the fastest one and it should works on Intel Atoms, but not on ARM. Feel free to use any part of code in any of you programs, I know that this code is little to much to add it into rtl_fm, but maybe it could somebody help to recieve HW stereo FM radio. Speed of SSE code is much better than anything you can get around here, on Core i7 it consume only 5% of one CPU, so i could demodulate at least 80 channels at the same time in stereo quality of course. I tried this code only on AMD64 and GCC Linux, so i am not sure if it can be compiled under windows. -- Miroslav Slugeň +420 724 825 885 Teramos Multimedia s.r.o.

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Announcing the SoapySDR project
by Josh Blum 12 Nov '14

12 Nov '14

Hello list, I am pleased to announce the SoapySDR project. SoapySDR is a vendor neutral and platform independent SDR support library. The library provides a generic API for accessing SDR devices, and a plugin architecture for supporting vendor hardware drivers. Currently SoapySDR offers both a C++ and a C API, as well as Python language bindings. SoapySDR already supports most devices through osmosdr and uhd based plugins. The API covers an almost complete superset of available functionality found in these libraries. Therefore, there is an API for things like burst controls, heterogeneous channels, timed streaming, timed command, find tuning adjustments, automatic gain controls... I have seen a lot of applications where the developer has gone through the trouble of wrapping several low level drivers to gain support for each new device. But this can be way easier: you can use SoapySDR right now, write the code once, and have support for most devices. Please read more about SoapySDR on its main project page: https://github.com/pothosware/SoapySDR/wiki -- Community feedback -- Making a generic library has its challenges, and we will probably never get it 100% right. But with feedback from vendors and users, we can make sure the the library has what most people need. Missing a feature? Need another language binding? Don't like the way something works? Lets hear it. https://github.com/pothosware/SoapySDR/wiki/FAQ -- GNU Radio blocks -- We have created out-of-tree GNU Radio source and sink blocks based on SoapySDR that can provide a GNU Radio interface for the vast majority of SDR devices and capabilities: https://github.com/pothosware/gr-sdr/wiki Volunteers? The source and sink blocks have full basic functionality, but there are still additional APIs to wrap and apps to port over. The eventual goal is to mainline this component into GNU Radio: https://github.com/pothosware/gr-sdr/issues There has been some debate over what would be a good name for this GNU Radio component. Please help us with feedback about the name by taking this online poll: https://github.com/pothosware/gr-sdr/wiki#help-us-name-gr-sdr -- Hardware vendors -- If you are a hardware vendor, chances are that your device is already supported through the uhd or osmo libraries. However, you may be interested in directly hosting a SoapySDR support module along with your low-level driver: for simplicity's sake, licensing reasons, or because it exposes additional features. Hosting a module build with along with the driver is fairly simple and has many advantages. I'm happy to work with anyone who is interested: https://github.com/pothosware/SoapySDR/tree/master/ExampleDriver Thanks, -Josh

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Spectrum Sensing App
by John Wright 10 Nov '14

10 Nov '14

Has anyone tried the Spectrum Sensing app that is listed as a part of OsmocomSDR? http://sdr.osmocom.org/trac/wiki/GrOsmoSDR It seems that documentation for it is in the works. I need to generate a spectrum survey log file comprising time, frequency and signal strength. My RF front end is a HackRF. Any pointers would be greatly appreciated. Thanks!

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Bandwidth of the dvb-t dongle
by lists 09 Nov '14

09 Nov '14

I saw a post about Nooelect sellings the dvb-t2 dongle and that it is slightly wider bandwidth than the plain dvb-t dongle. > http://www.rtl-sdr.com/nooelec-now-selling-rtl-sdrs-r820t2-tuner/ Looking up DVB-T2 on google, it indicates the bandwidth is 8MHz. There is a plot on the older DVB-T wiki of a DVB-T signal at about 7.5MHz bandwidth. So the question is why do we only see +/- 2MHz? The dump1090 program would benefit with more bandwidth.

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osmocom-sdr November 2014