osmocom-sdr

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904 discussions

by James Peroulas

> Date: Mon, 27 Aug 2012 12:27:21 +0200 > From: Christian Buchner <christian.buchner(a)gmail.com> > > For some reason, your CellSearch software worked the second time I ran > it. Here's the result for a scan in Munich. The two frequencies found > correspond to the operators O2 and Vodafone. Deutsche Telekom is > either not using the 800 MHz band here, or I happen to be out of the > reception range for this dongle. > > Detected the following cells: > C: CP type ; P: PHICH duration ; PR: PHICH resource type > CID fc foff RXPWR C nRB P PR CrystalCorrectionFactor > 449 796M -13.2k -47.7 N 50 N one 0.99998344473785039099 > 372 806M -13.2k -43.7 N 50 N one 0.99998362964129883235 I see that the received signal power is very low at -44dB, so it kind of makes sense that these cells would not be detected every time you run the program. I suspect that if you moved outdoors or used a tuned LTE antenna, these cells would be detectable more reliably. > This software project is way cool! I am surprised how precise my crystal is. > > Now who's willing to extend the code to combine several dongles to > scan the full 10 MHz band and to analyze the allocated resources > signalled on the PDCCH so we can generate statistics on cell load and > number of UEs served? Wow, I think that would be a major undertaking for these dongles! I think that's a task best suited for the USRP and the OpenLTE project :) JP

12 years, 11 months

LTE Cell Scanner

by James Peroulas

I just released an LTE cell scanner based on the rtlsdr library. If you're interested, the code is available on github: https://github.com/Evrytania/LTE-Cell-Scanner This code will search for all the LTE cells in your area and will also report the frequency error of your dongle. BR, James P.S. Many thanks for the rtlsdr library! -- Integrity is a binary state - either you have it or you don’t. - John Doerr

12 years, 11 months

Re: osmocom-sdr Digest, Vol 9, Issue 16

by James Peroulas

> Message: 1 > Date: Fri, 24 Aug 2012 18:11:59 +0200 > From: Christian Buchner <christian.buchner(a)gmail.com> > To: osmocom-sdr(a)lists.osmocom.org > Subject: Re: LTE Cell Scanner > Message-ID: > <CALm6U+pZd8Ufmu1UCOQ_+0ebMc_joDOh9_dFW0g=1QW=M2p02A(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > I was able to build it on Ubuntu 9.04 (Jaunty Jackalope) with a little > upgrading of some dependencies. > > CellSearch is now crashing in the static initializer for the > ROM_TABLES object. *sigh* > > Would anyone have an idea what may be is causing it? > > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread 0xb773b910 (LWP 21087)] > 0x00f743fe in itpp::Vec<std::complex<double> >::set_size () from > /usr/local/lib/libitpp.so.7 > Current language: auto; currently asm > (gdb) where > #0 0x00f743fe in itpp::Vec<std::complex<double> >::set_size () from > /usr/local/lib/libitpp.so.7 > #1 0x00f74ada in itpp::Vec<std::complex<double> >::operator= () from > /usr/local/lib/libitpp.so.7 > #2 0x0808b0cd in PSS_fd::PSS_fd () > #3 0x08094444 in global constructors keyed to ROM_TABLES () > > Christian Are you still having problems with this? Can you try upgrading to the latest github code? I changed the initialization sequence for the ROM_TABLES and it might fix your problem too. BR, James

12 years, 11 months

RTL_FM fails on OS X

by Christoph Gommel

Hello, I was completely happy that rtl-sdr builds without any problems in my iMac (with OSX 10.8.1 and latest Macports). Using a RLT2832-Dongle that is plugged into my mac on other machines via rtl_tcp works well, also recording data is working. What fails is running rtl_fm: iGommel:build chg$ rtl_fm -f 97300000 -s 44100 test.raw Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000291 Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Found Elonics E4000 tuner Oversampling input by: 23x. Oversampling output by: 1x. Buffer size: 8.08ms Tuned to 97553575 Hz. Sampling at 1014300 Hz. Exact sample rate is: 1014300.020041 Hz Tuner gain set to -1.00 dB. Floating point exception: 8 Unfortunately i don't have the debugging skills to find the position of the Floating point exception without a high-level GUI ;) Any idea what can be done by me to help chasing the bug? Christoph

12 years, 11 months

BONANZA - The e4000 *complete* reference document :)

by Ben Ryan

Hey all, Got some gold for ya's. Registers, the works. Even a reference design schematic. Grab it while it's hot, before the lawyers catch on.. and thanks guys for all your hard work with RTLSDR! https://skydrive.live.com/redir?resid=E55F3F5F75B5A7BB!1160

12 years, 11 months

[benzandstra@caiway.nl: Small comment about the rtl-sdr wiki]

by Harald Welte

FYI, -- - 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)

12 years, 11 months

[jarribas@cttc.es: GNSS-SDR now supports the RTLSDR signal source]

by Harald Welte

Hi all! I'm forwarding this announcement from the GNSS-SDR developers. I will also put it on the sdr.osmocom.org site. Congratulations to steve-m, horizon, hoernchen and the team! Regards, Harald -- - 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)

12 years, 11 months

Say Enter "RTL readlen=524288" in the 'ExtIO : Device hint' edit field, when that is what you mean

by Jay Salsburg

OK I get it. I wish those who write this stuff were not so Cryptic and Acronymous. On this page ... http://wiki.spench.net/wiki/USRP_Interfaces the author has an entry that looks like this "RTL readlen=524288" yet nowhere in the immediate text is there any language stating to enter this text in the 'ExtIO : Device hint' edit field, you have to sort of guess the author thoughts. No one is ever thinking like the one who is doing the original thinking so to reproduce original thinking adequate references to what the author is thinking is required to reproduce the original thoughts in the reader's mind. Literate illustration makes everything so much easier (and a liberal sprinkling screen shots). Thanks Jay Salsburg

12 years, 11 months

The real problem with this thing

by Jay Salsburg

I have been hacking into one of those $20 DVB-T TV Tuner Dongles. To get it to tune to the Freq I want I use the usual method with the ExtIO Drivers. The real problem with this thing, as far as making good use of the valuable E4000, is the RTL2832, even though controlling the Tuner through the USB requires the RTL2832. This clumsy Analog to Digital Converter / USB interface Chip, does not have the Audio dynamic range needed for my purposes. The infuriating predilection it has to crash every time you want to shift frequency is another disadvantage. Since the Owners of the E4000 have gone into Bankruptcy, I am taking the initiative to hack the Tuner. First, I attached a high gain audio amplifier's input directly to the Tuner's output then to a 96K Sample per Second, 24 Bit Audio card to observe a high quality spectral image from the tuner. Next is to hack into and record the I2C sent to the Tuner, so it may be controlled independent of that infuriating RTL2832. If anyone has done this, please share your code and understanding. Thanks Jay Salsburg

12 years, 11 months

Re: [Discuss-gnuradio] FCD/Alsa bug (Re: Bug hunting)

by don.lewis＠dses.org

Sent via the HTC V..b.livid™, anbURL: http://maps.google.com/maps?q=40.031769,-105.2;Kn)na?bks3213, 3128 Bell Dr, Boulder, CO 80301, USA AT&T 4G -3$/-)44+$LTE( (::,2mk: ----- Reply message ----- From: "Christian Gagneraud" <chris(a)techworks.ie> To: "Dimitri Stolnikov" <horiz0n(a)gmx.net> Cc: <discuss-gnuradio(a)gnu.org>, <osmocom-sdr(a)lists.osmocom.org> Subject: [Discuss-gnuradio] FCD/Alsa bug (Re: Bug hunting) Date: Wed, Aug 8, 2012 9:02 am Cross posting to discuss-gnuradio. The bug in question is that if you instanciate an alsa source on a busy device (opened by another app), then the program crashed. On 08/08/12 00:23, Dimitri Stolnikov wrote: > Hi Christian, [...] > > The other problem (segfault on trow in ctor) still has to be addressed. Yes, I started to investigate, and it seems to me that this is not a gr-osmosdr bug, but it's a gnuradio one, caused by gr-fcd. This simple test program have the same problem, yet it only uses gr-fcd. #include <iostream> #include <fcd_source_c.h> int main(int argc, char **argv) { fcd_source_c_sptr fsrc; try { fsrc = fcd_make_source_c("hw:2"); // KO, from gr-fcd } catch (std::runtime_error &e) { std::cerr << "Error!\n"; } exit(0); } g++ test.cc -o test -I/usr/local/include/gnuradio -lgnuradio-fcd Here is the log: audio_alsa_source[hw:2]: Device or resource busy Error! *** glibc detected *** /home/cgagneraud/sdr/gr-osmosdr/test: free(): invalid pointer: 0x08052e3c *** [...] And here is a cleaned up backtrace: operator delete gruel::msg_accepter::~msg_accepter checked_delete<gr_hier_block2> boost::detail::sp_counted_impl_p<gr_hier_block2>::dispose [...] const, boost::shared_ptr<gr_basic_block> > > >::~map __cxa_finalize __do_global_dtors_aux [...] main The problem is related to gnuradio-core/src/lib/runtime/gr_sptr_magic.{h,cc} and the static std::map in there. gr_hier_block2 ctor insert "this" in this map, but then in fcd_source ctor, audio_alsa_source ctor throws an exception, so "this" (gr_hier_block2/fcd_source) is not a valid pointer anymore. When the program exits, the map get cleanup up and free is called on this pointer. It's not possible to cleanup the map in fcd_source, because the dtor is not called when exception occurs in the ctor (which, btw, leads to some memory leaks in alsa_source: namely d_hw_params and d_sw_params). It's a bad idea to call fetch_initial_sptr(this) before throwing in the ctor, because it seems the object get deleted.

12 years, 12 months

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