osmocom-sdr

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904 discussions

r820t2 based receiver raw samples ?
by Jean-Michel FRIEDT 12 Nov '16

12 Nov '16

I am attempting to use a RTL2832U based DVB-T dongle as a "fast" ADC for recording baseband signals. gr-osmosdr under GNURadio 3.7 (as provided by Debian GNU/Linux) provides the expected samples when using an E4000 (zero IF) dongle. Being obsolete, such a dongle is no longer relevant, and I want to do the same with the (non-zero IF) R820T(2) dongles. From http://sdr.osmocom.org/trac/wiki/GrOsmoSDR I should be able to use the direct_samp=1|2 option, but that does not work. I kept pins 1 and 2 connected to the R820T output and connected a wire to pin 5 (Q-) while Q+ (pin 4) is short circuited to pin 3 (gnd). A signal generator outputs a periodic signal (150 mV amplitude, 100 kHz) but still no baseband signal, and on the FFT of the osmosdr output I still see the spectrum of the FM band when tuning to 100 MHz rather than the samples from the (initially unconnected) Q input. Any idea if the "Device Arguments" of osmosdr-source is actually parsed and interpreted ? or is there a command line way of acquiring the raw baseband I/Q data ? Thanks, JM -- JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 Besancon, France ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.

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[PATCH] hackrf: fix buffer underflow
by P 28 Oct '16

28 Oct '16

Hi, lib/hackrf/hackrf_source_c.cc | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) this patch fixes SIGSEG wich happens when buffer from GnuRadio is bigger than buffers used by HackFR. This is due to 'remaining' will become bigger than size of input buffer. More than available bytes might be copied and '_samp_avail' become negative. This soon or latter becomes SIGSEG. With best regards, P

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Fix for Airspy MIXER gain
by Lucas Teske 26 Oct '16

26 Oct '16

So I was having a problem with my GOES LRIT receiver in GNU Radio. In GQRX the SNR was 7dB and in GNU Radio was 4dB regardless of the setting. Then I noticed that the Mixer (BB Gain) wasn't working at all. Checked over the internet and there was this issue: So I made some changes and here is the working version: https://github.com/osmocom/gr-osmosdr/pull/8 (I know its a mirror, but the patch is also attached) Lucas Teske

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Installation error
by Ashish Kurian 06 Oct '16

06 Oct '16

Hi All, I downloaded the tar ball release libgtpnl-1.0.1.tar.gz and un tared it. Then I tried to build and install the package. But the command sudo ./configure is giving me the following error. configure: error: cannot find install-sh, install.sh, or shtool in build-aux "."/build-aux Do you know what could be the reason for this error? Best Regards, Ashish Kurian

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Re: Moving from trac to a single redmine
by Harald Welte 26 Sep '16

26 Sep '16

On Sun, Sep 25, 2016 at 05:54:10PM +0200, Neels Hofmeyr wrote: > On Sat, Sep 24, 2016 at 08:01:52AM -0600, Sylvain Munaut wrote: > > I've just put this in place for 'openbsc.osmocom.org' : > > > > rewrite ^/trac/wiki/(.*)/(.*)$ > > $scheme://osmocom.org/projects/openbsc/wiki/$1$2 redirect; > > rewrite ^/trac/wiki(.*)$ $scheme://osmocom.org/projects/openbsc/wiki$1 redirect; > > But so far the idea is to keep the trac online and browsable, right? the main problem is that search engines still primarily seem to index + link to the old trac instances. So we were keeping that alive for some time. However, as the content is going out of date, and people still show an interest in editing the old content, I think we need to switch the trac off soon and replace it with links to the redmine, even if it just links to the redmine entry page of that project. -- - 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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Moving from trac to a single redmine
by Holger Freyther 25 Sep '16

25 Sep '16

Hi guys, I think some of us would like to move to redmine and start using public tickets more frequently. So in case we move there are some topics to be discussed and I would like to start with a couple of them right now. Tickets: Redmine has a global linear sequence of ticket numbers. If we move from many tracs to a single redmine we can either: * not import tickets * only import from one project * deal with changing ticket numbers In terms of installations the GMR trac is broken in regard to tickets, there are some for SDR that are probably not being fixed anytime soon, baseband might be relevant and OpenBSC is unlikely to be relevant. I don't think we have ever used ticket reference in OpenBSC commit messages so in terms of OpenBSC having changing ticket numbers would not be a big deal. E.g. we could add a custom field with the old trac number? Wiki: We have external references that should be redirected to the new place. Is there any way besides maintaining a list in the apache2/nginx configuration and making redirects as we find broken references? Can we proactively manage this? Is anybody willing to come up with a script and nginx configuration for doing this? kind regards holger

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Help needed with DSP filter problems
by Neoklis Kyriazis 02 Sep '16

02 Sep '16

Hi I have been experimenting writing DSP software, using librtlsdr and a NESDR dongle from NooElec. After much searching the Internet for code to design and implement DSP filters (with little success), I remembered that years ago I bought the "Digital Signal Processing" book by Steven W. Smith. I used the BASIC software included to produce C code to calculate the a and b coefficients for Low Pass or High Pass Chebyshev filters, from 2-pole to 20-pole if needed. Unfortunately, the cut-off frequency for a 6-pole Low Pass filter I implemented turns out to be 2x the required value, even though the design function that calculates the a and b coefficients produces values that match exactly values tabled in the book. This leaves me I think with the following possibilities: 1. That the calculated a and b coefficients are correct but my own code implementing a recursive filter is incorrect. 2. That I have incorporated the LPF filter function into my librtlsdr-based application incorrectly, perhaps misunderstanding parameters like the sampling rate or the required bandwidth. 3. That both the above implementations are correct but the BASIC code included in the book has a bug somewhere, so that both my own results for a and b and those tabled in the book are incorrect. Rather unlikely I thought.... So I am asking for help here from more knowledgeable DSP'ers hoping to resolve this matter, as the above mentioned book is very good, with very clear and simplified teaching of DSP for engineers _and_ it includes source code in BASIC for most of the algorithms it teaches. And it is available openly on the Internet with source code here!: http://dspguide.com/ My own GPL'ed application is available for inspection here: www.5b4az.org/pkg/sdrx/sdrx-0.3-beta.tar.bz2 The filter functions are in src/filters.c and SDR functions in src/rtlsdr.c My thanks here in advance! -- Best Regards Neoklis - Ham Radio Call:5B4AZ http://www.5b4az.org/

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Raspberry Pi 2B
by Leif Asbrink 02 Sep '16

02 Sep '16

Hi All, This video shows that one can run a rtlsdr at 2.4 MHz on a Raspberry Pi 2B. Maybe interesting for portable use. https://www.youtube.com/watch?v=qGZmD8O4Flk Regards Leif

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Re: osmocom-sdr Digest, Vol 21, Issue 2
by CT2FZI IM58kr 25 Aug '16

25 Aug '16

unsubscribe Em 24/08/2016 22:55, <osmocom-sdr-request(a)lists.osmocom.org> escreveu: > Send osmocom-sdr mailing list submissions to > osmocom-sdr(a)lists.osmocom.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.osmocom.org/mailman/listinfo/osmocom-sdr > or, via email, send a message with subject or body 'help' to > osmocom-sdr-request(a)lists.osmocom.org > > You can reach the person managing the list at > osmocom-sdr-owner(a)lists.osmocom.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of osmocom-sdr digest..." > > > Today's Topics: > > 1. PATCH: Fixed arbitrary resampling in rtl_fm > (f.meyer-hermann(a)gsg-elektronik.de) > 2. Uccess! My first librtlsdr application (Neoklis Kyriazis) > 3. Re: Uccess! My first librtlsdr application (Lucas Teske) > 4. Fwd: Development of rtl-sdr driver (Piotr Krysik) > 5. RTL-SDR and RTL-TCP drivers (Krzysztof Halasa) > 6. [PATCH] RTL-SDR: convert _lut to float[] to reduce size by a > factor of 256 (Krzysztof Halasa) > 7. [PATCH] RTL-TCP: Convert to single class model (Krzysztof Halasa) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 25 Jul 2016 13:13:13 +0200 > From: f.meyer-hermann(a)gsg-elektronik.de > To: osmocom-sdr(a)lists.osmocom.org > Subject: PATCH: Fixed arbitrary resampling in rtl_fm > Message-ID: <20160725111313.GA15278(a)gsg-elektronik.de> > Content-Type: text/plain; charset=us-ascii > > As already on github, I fixed rtl_fm's arbitrary resampling by fixing the > output buffer length and allowing upsampling by copying the audio data > since > the algorithm cannot work in-place. > I have attached a patch, if you are interested to integrate it into the > official branch. > Regards, > > Ferdinand Meyer-Hermann > > > ------------------------------ > > Message: 2 > Date: Fri, 5 Aug 2016 05:09:49 +0000 (UTC) > From: Neoklis Kyriazis <nkcyham(a)yahoo.com> > To: "osmocom-sdr(a)lists.osmocom.org" <osmocom-sdr(a)lists.osmocom.org> > Subject: Uccess! My first librtlsdr application > Message-ID: > <1565657774.9528793.1470373789409.JavaMail.yahoo(a)mail.yahoo.com> > Content-Type: text/plain; charset=UTF-8 > > Hi > > > First, my thanks to everyone involved with the development and > release of librtlsdr. Well done. :-) > > I always wanted to try my hand building an SDR application and > so I installed the latest librtlsdr and started writing code > > to test the various functions in the librtlsdr library. Having > gotten familiar with this, I started work on modifying my old > Wx satellite APT image decoder app, xwxapt, to support an rtlsdr > receiver beside the linear VHF receiver it was written for. > > Its always difficult to extensively modify an existing app, but > in the end it all worked out well and xwxapt can now receive the > old APT format images from Wx sats with the rtl-sdr receiver. In > the process, I modified xwxapt to include controls for the rtl-sdr > unit, display an FFT-derived spectrum of the 2.4kHz sub-carrier > and a spectrum of the baseband O/P of the RTL2832 device. Images > are decoded in real time and displayed incrementally in xwxapt's > window. xwxapt is available under the GPL at: > > > http://www.5b4az.org/ in Weather Imaging->Image Decoders menu. > > -- > Best Regards > Neoklis - Ham Radio Call:5B4AZ > http://www.5b4az.org/ > > > ------------------------------ > > Message: 3 > Date: Fri, 5 Aug 2016 13:29:29 -0300 > From: Lucas Teske <lucas(a)teske.net.br> > To: osmocom-sdr(a)lists.osmocom.org > Subject: Re: Uccess! My first librtlsdr application > Message-ID: <fb16ab1f-4ff9-3ba5-04a0-5b1231fa72ef(a)teske.net.br> > Content-Type: text/plain; charset="utf-8" > > Nice Neoklis! > > > It looks good, I will give a try on the weekend :D > > > Btw, you should post the source-code at github, in this way it is easier > to submit patches and stuff. > > > Lucas > > Em 05/08/2016 02:09, Neoklis Kyriazis escreveu: > > Hi > > > > > > First, my thanks to everyone involved with the development and > > release of librtlsdr. Well done. :-) > > > > I always wanted to try my hand building an SDR application and > > so I installed the latest librtlsdr and started writing code > > > > to test the various functions in the librtlsdr library. Having > > gotten familiar with this, I started work on modifying my old > > Wx satellite APT image decoder app, xwxapt, to support an rtlsdr > > receiver beside the linear VHF receiver it was written for. > > > > Its always difficult to extensively modify an existing app, but > > in the end it all worked out well and xwxapt can now receive the > > old APT format images from Wx sats with the rtl-sdr receiver. In > > the process, I modified xwxapt to include controls for the rtl-sdr > > unit, display an FFT-derived spectrum of the 2.4kHz sub-carrier > > and a spectrum of the baseband O/P of the RTL2832 device. Images > > are decoded in real time and displayed incrementally in xwxapt's > > window. xwxapt is available under the GPL at: > > > > > > http://www.5b4az.org/ in Weather Imaging->Image Decoders menu. > > > > -- > > Best Regards > > Neoklis - Ham Radio Call:5B4AZ > > http://www.5b4az.org/ > > >

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Fwd: Development of rtl-sdr driver
by Piotr Krysik 08 Aug '16

08 Aug '16

Hi everyone, I've send the e-mail to the OpenBSC list before, but as I was informed by Harald this is the right place for such discussions. So I'm resending it here. The osmocom's version of rtl-sdr driver seems to be the main one. Osmocom's repository is used by distributions to build rtl-sdr packages and it is source of the code for compilation with use of GNU Radio's Pybombs. Is there someone in the Osmocom who is maintaining it? There were some important developments regarding this driver and it would be great to add these patches in the Osmocom's repo. For example one that interests me is turning off dithering so multiple dongles sharing the same clock generate the same LO frequency. Currently there is always little frequency offset that makes coherent of the receivers operation much harder. Such changes of course have to be done carefully so nothing gets broken in the process. In case of turning off dithering it results with worse tuning granularity, so for example turning it off could be made optional. -- Best Regards, Piotr Krysik

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