December 2015 - osmocom-sdr - lists.osmocom.org

Sampling at 250 kHz without aliasing
by Syed Karim 12 May '16

12 May '16

We have a need for a small sample rate on the rtl-sdr. We have been able to select a bandwidth of 250 kHz, but there is significant aliasing at that setting. At higher sample rates the aliasing no longer exists. We are using the dongle that is sold by the RTL-SDR.com blog: http://www.rtl-sdr.com/new-products-rtl-sdr-with-1ppm-tcxo-sma-f-connector-… Since a reduced sample rate would allow for a much less resource consumption by the CPU, we would gladly sponsor an open source bounty or pay for open source development work to address this problem. Our use case is reception of a 5 kHz channel from a geostationary L-band operator. We have found that the dongle gets very hot at 1550 MHz, so we will use an LNB to downconvert to ~400 MHz. The rest of the RF chain consists of a patch antenna with 8 dBi of gain and 17 dBW EIRP from the spacecraft. The demodulator will be running on a derivative of the Beagle Bone Black. The designs for this board are available here: https://github.com/outernet-project/lantern-compute-pcb You can learn more about Outernet through the following links. http://gizmodo.com/what-is-the-outernet-and-is-it-the-future-of-the-intern-… http://www.wired.com/2015/07/plan-beam-web-3-billion-unconnected-humans/ http://www.technologyreview.com/news/537411/startup-beams-the-webs-most-imp…

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Heatmap with unwanted vertical lines
by John 12 May '16

12 May '16

Hello, When I use heatmap.py with output from rtl_power I get regularly spaced vertical lines that do not appear to be related to any signal. They look they like repeat at the dongle bandwidth (2048000Hz in this case). The crop option for rtl_power reduces the presence but I am not sure f that is intended by that option. Even at -c of 70% they are still there (see attachment). Is this because of small bin width? If I use a larger bin (32k) they are still there. In this case there is no frequency legend along top so can't compare if they happen more often. Are these lines to be expected? John

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Fixing gr-fosphor compilation
by Elliot Saba 11 May '16

11 May '16

After pulling gr-fosphor `master` today and compiling against the latest GNURadio, I noticed that it failed when attempting to link against libgnuradio, due to missing pmt symbols. The attached one-line patch fixes the issue, but I imagine would break compilation against older GNURadio releases. If there is a better way for me to submit this patch, please let me know. I had previously emailed one of the gr-fosphor developers with a separate issue regarding libpng issues out of ignorance of this mailing list. I don't want to disturb you developers any more than need be, so if there is a better forum than this for patches/pull requests, I am more than happy to use it. -E

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sdrangelove build issues on mipsel
by Arturo Borrero Gonzalez 03 May '16

03 May '16

Hi there, In debian, sdrangelove is having some build issues on mipsel [0]. At first, there was an issue regarding the '-msse2' switch. If I delete the switch, then another build error happens: ======== 8< ======== [...] [ 21%] Building CXX object CMakeFiles/sdrbase.dir/sdrbase/dsp/interpolator.cpp.o /usr/bin/c++ -DQT_CORE_LIB -DQT_GUI_LIB -DQT_MULTIMEDIA_LIB -DQT_NETWORK_LIB -DQT_NO_DEBUG -DQT_OPENGL_LIB -DQT_WIDGETS_LIB -DUSE_FFTW -Dsdrangelove_EXPORTS -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -O3 -DNDEBUG -fPIC -isystem /usr/include/mipsel-linux-gnu/qt5 -isystem /usr/include/mipsel-linux-gnu/qt5/QtCore -isystem /usr/lib/mipsel-linux-gnu/qt5/mkspecs/linux-g++ -isystem /usr/include/mipsel-linux-gnu/qt5/QtWidgets -isystem /usr/include/mipsel-linux-gnu/qt5/QtGui -isystem /usr/include/mipsel-linux-gnu/qt5/QtOpenGL -isystem /usr/include/mipsel-linux-gnu/qt5/QtMultimedia -isystem /usr/include/mipsel-linux-gnu/qt5/QtNetwork -I/tmp/buildd/sdrangelove-0.0.1.20140824/obj-mipsel-linux-gnu -I/tmp/buildd/sdrangelove-0.0.1.20140824/include -I/tmp/buildd/sdrangelove-0.0.1.20140824/include-gpl -fPIC -o CMakeFiles/sdrbase.dir/sdrbase/dsp/interpolator.cpp.o -c /tmp/buildd/sdrangelove-0.0.1.20140824/sdrbase/dsp/interpolator.cpp In file included from /tmp/buildd/sdrangelove-0.0.1.20140824/sdrbase/dsp/interpolator.cpp:4:0: /tmp/buildd/sdrangelove-0.0.1.20140824/include-gpl/dsp/interpolator.h:4:23: fatal error: immintrin.h: No such file or directory #include <immintrin.h> ^ compilation terminated. [...] ======== 8< ======== Do you have any hint for this? Thanks, best regards. PS: Please keep me in CC, i'm not subscribed. [0] https://buildd.debian.org/status/fetch.php?pkg=sdrangelove&arch=mipsel&ver=… -- Arturo Borrero González

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Re: [rtl-sdr][PATCH 1/2] rtl_fm: Add scanner progress
by Nikolay Dimitrov 15 Jan '16

15 Jan '16

Oops, forgot to CC the mailing list. On 09/21/2015 12:47 PM, Nikolay Dimitrov wrote: > Hi Dimitri, > > On 07/04/2015 03:42 PM, Nikolay Dimitrov wrote: >> Add scanner progress, including signal and squelch levels. >> Rename demod_state->conseq_squelch to demod_state->squelch_conseq. >> >> The scanner progress feature can be tested like this: >> >> ./rtl_fm -f 144.000M:146.000M:25k -M fm -s 48k -l 100 -t 5 | aplay \ >> -r 48k -f S16_LE -t raw -c 1 >> >> Signed-off-by: Nikolay Dimitrov <picmaster(a)mail.bg> >> --- >> src/rtl_fm.c | 43 +++++++++++++++++++++++++++++-------------- >> 1 file changed, 29 insertions(+), 14 deletions(-) > > Can you please take a look at this patch and decide whether it's worthy > of applying to the rtl-sdr tree? > > Thanks in advance. Regards, > Nikolay

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[PATCH] clear warnings about compare signed-unsigned values
by P 10 Jan '16

10 Jan '16

This just removes few annoying warnings. About the conversion of string to signed int. - dev_index = boost::lexical_cast< unsigned int >( hackrf_serial ); + dev_index = boost::lexical_cast< int >( hackrf_serial ); hackrf_device_list_open checks if value of dev_index is out of range (eg negative) and returns proper error. In future negative value can be used for something so this check is not necessary nor wanted. P

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gr-osmosdr setting value in destructor
by P 10 Jan '16

10 Jan '16

Hi, there is in gr-osmosdr a lot of code like: hackrf_source_c::~hackrf_source_c () { ... free(_buf); _buf = NULL; } } Setting value in destructor have sense in two case: - they are used in some way in destructor of parent class - You set then to something like 0xDEADBEEF and when pointer from already destroyed class is used it will cause segfault. Setting value to NULL is contraproductive because there is a lot of checks if value is not NULL, this actually can hide some troubles of calling something using already freed pointer. I'm suggesting to remove this kind of code. I will prepare patch but now I'm waiting if those two pending patches I have send before would be accepter or not. Is there any opinion which oppose previous claim? With best regards, JP.

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gr-osmosdr broken on OSX due to MSG_NOSIGNAL
by Elliot Saba 10 Jan '16

10 Jan '16

It looks like the block to redefine MSG_NOSIGNAL as SO_NOSIGPIPE inside of redpitaya_common.cc needs to be copied into redpitaya_sinc_c.cc as well. -E

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osmocom_fft won't tune BladeRF lower than 300MHz
by Ben Z en de rest 29 Dec '15

29 Dec '15

Hi. Today I installed latest gr-osmosdr. I want to run osmocom_fft and view the recorded file in "inspectrum". Osmocom_fft starts, runs, knows there is a BladeRF available and does work. only thing is that it does not allow tuning lower then 300 MHz as if the transverterboard is unknown to the osmocom_fft. I tried to start osmocom_fft with -a balderf but that does not help. If I set it to for example 145M it gives this message: Failed to set out of bound frequency: 1.45e+08 libbladerf is updated last weekend. Any ideas on this ? Thanks, Ben

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Cmd structure for rtl_tcp
by jmaurin＠jonis.com.br 29 Dec '15

29 Dec '15

Hi List! I'm new here, so I hope I'm asking for help in the right place. I'm trying to build and application that read I/Q data from rtl_tcp using Delphi. For beginning, I'm trying to set some params for rtl_tcp using my remote app. I found the source code of rtl_tcp and I could identify some information about what is each command, like 0x01 (hex) is to set frequency, 0x02 to set sample, etc.... What I don't undertand is the structure of parameters. Each parameter is one byte? If not, how parameters are sent? Do I need to send char to end command, like end of line or carrier return? Is not, what's the correct structure for sending commands? For example: For setting gain, send one byte with 0x04 and another byte indicating the gain index. Tks! Jonis Maurin Ceará

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