December 2013 - osmocom-sdr - lists.osmocom.org

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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rtl_tcp problem or not?
by Favati 25 Feb '14

25 Feb '14

Hi there! I'm using a dongle on a raspberry + rtl_tcp and sdrsharp on another machine (quad core.... 3gb ram...good machine!) The problem occour at 00:57 http://www.youtube.com/watch?v=4E2MPfEzEi8 and at 1:34 in this video: http://www.youtube.com/watch?v=8snz1wQSRpw If i stop and start sdrsharp, it works ok for some minutes...then the problem is up again! No errors appear on the console of raspberry/rtl_tcp I'm not able to understand if it's a problem of rtl_tcp,raspberry or whatelse... Things i've tryed: 1) Changed the samplerate 2) Changed the raspberry (tested tp1/tp2 too...getting 4.98v!!!) 3) Changed the dongle 4) Updated sdrsharp The dongles tryed work ok on a pc I've no more idea.... Anyone can help me? PS: If someone know a program that works in linux and is similar to sdrsharp AND CAN INTERFACE TO A REMOTE RTL_TCP...

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odd results working at 250ksp/s
by David Jacobowitz 10 Feb '14

10 Feb '14

Hi, I've been working on a project the involves tuning VOR signals. They are narrow band signals. > 25 kHz. For that, the wide bandwidth of the RTL dongles isn't that helpful to me. (and actually a hindrance when two signals are inside the sample range but widely different strengths) Anyway, the lowest I can get my dongles (R820T) to go is 250ksps, which is fine. I've been working at that frequency for awhile, but getting some strange results. For example, if I tune in to 116.8 MHz, which should be the OAK VOR, it works fine. But if I tune to 115.8 MHz, which should be the SFO VOR I get ... the OAK VOR. That is, there is a perfect copy of the OAK signal 1 MHz shifted down. If I switch the sample rate to 1.024Msps or 900ksps, I don't get this problem. I don't understand what is happening here. 1 MHz is an even multiple of 250kHz, so maybe I'm getting an image of OAK overpowering the relatively weaker SFO signal. But should there not be filters that manage this? I guess I was expecting that if the device is set to 250ksps, then it would "close down" filters appropriately to reject signals out of that band. But maybe the filters don't work properly below a certain sample rate? Like the rtl2832 can sample down to 250ksps, but the 820T tuner was not designed for it? Or perhaps I'm doing something wrong? Can I control the filters directly? I'm glad I find this issue because I was going nuts thinking my software had some mysterious bug. But I can reproduce this issue just with SDR# or whatever. :-) Regards. Dave J

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RE: How to get IQ samples from multiple rtl-sdr dongles in asynchronized manner?
by Jiao Xianjun 02 Jan '14

02 Jan '14

Hi, I don't use the method of hardware modification. That can do synchronization promisingly, sure. I know this scheme couple of months ago, and good to know it works pretty well from you. My thought is doing the compensation by software according to a common source over the air instead of over the hardware. Do you think it is doable? And what would be the bottleneck according to your experience? Any possibility to tune the hardware by software after we estimate the synchronization error in frequency and timing? BR Jiao xianjun -----Original Message----- From: "Sdr Guru" <sdrguru1(a)gmail.com> Sent: ‎2013/‎12/‎30 19:01 To: "Jiao Xianjun" <putaoshu(a)gmail.com> Cc: "osmocom-sdr(a)lists.osmocom.org" <osmocom-sdr(a)lists.osmocom.org> Subject: Re: How to get IQ samples from multiple rtl-sdr dongles in asynchronized manner? Hi Are you using a common clock? http://kaira.sgo.fi/2013/09/16-dual-channel-coherent-digital.html I've modified some of the RTL dongles, played with GNURadio and Octave. The results are promising, sample level correlation (2.4M/10, FM radio signal). On Mon, Dec 30, 2013 at 9:38 AM, Jiao Xianjun <putaoshu(a)gmail.com> wrote: Hi guys, For the multiple dongles synchronization in signal level instead of bits/packets level, I setup a working repo in github, and write a initial demo framework. See below: https://github.com/JiaoXianjun/multi-rtl-sdr-udp-relay.git You may find information and instruction of demo quickly by reading the README. My initial purpose is performing in-fly calibration for multiple dongles according to some pre-known signal (GSM, ADS-B?) to let them work together coherently. An ideal scheme may be that we should generate a very narrow band and very week signal in (or just located at the edge of) target working band of dongles, and perform the software in-fly calibration in background (or driver level). This would be user friendly. Cheap (8USD+PP), simple, computer-controlled and legal FM band "marker" http://blog.palosaari.fi/2013/08/naked-hardware-12-usb-audio-transmitter.ht… I know it is far from final state currently, and many things are not clear yet (See TODO). But please join me if you also think this is a good idea. Just check out the demo and run it to have a look. Testing it and I'll let you know. Currently I just test the demo in Ubuntu-Linux. BR Jiao Xianjun On Mon, Sep 2, 2013 at 8:23 PM, Sylvain AZARIAN <sylvain.azarian(a)gmail.com> wrote: Thanks. sylvain 2013/9/2 Sdr Guru <sdrguru1(a)gmail.com> The second way, use MLAT enabled dump1090 https://github.com/antirez/dump1090/pull/23 http://www.satsignal.eu/raspberry-pi/dump1090.html On Sun, Aug 25, 2013 at 4:13 PM, Jiao Xianjun <putaoshu(a)gmail.com> wrote: Hi, I want to use multiple rtl-sdr dongles to do some multi-antenna experiments. Is it possible to read IQ samples from multiple rtl-sdr dongles in a synchronized manner? I already have a glance at dump1090 codes, which is a project using rtl-sdr to decode aircraft broadcasting ADS-B messages in 1090MHz. Seems that I should use rtlsdr_read_async() instead of rtlsdr_read_sync(), because that if rtlsdr_read_sync() is used, I have to call it multiple times sequentially. That looks not synchronized. But rtlsdr_read_async() function only accept one rtl-sdr device as input parameter, and it will be blocked after it is called. So seems that it also can't be used for my purpose directly. Also welcome any opinion on how to improve rtl-sdr lib/driver to support this feature. Thank you. BR Jiao Xianjun

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How to get IQ samples from multiple rtl-sdr dongles in a synchronized manner?
by Jiao Xianjun 02 Jan '14

02 Jan '14

Hi, I want to use multiple rtl-sdr dongles to do some multi-antenna experiments. Is it possible to read IQ samples from multiple rtl-sdr dongles in a synchronized manner? I already have a glance at dump1090 codes, which is a project using rtl-sdr to decode aircraft broadcasting ADS-B messages in 1090MHz. Seems that I should use rtlsdr_read_async() instead of rtlsdr_read_sync(), because that if rtlsdr_read_sync() is used, I have to call it multiple times sequentially. That looks not synchronized. But rtlsdr_read_async() function only accept one rtl-sdr device as input parameter, and it will be blocked after it is called. So seems that it also can't be used for my purpose directly. Also welcome any opinion on how to improve rtl-sdr lib/driver to support this feature. Thank you. BR Jiao Xianjun

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OsmoDevCon 2014 / Date / Venue
by Harald Welte 01 Jan '14

01 Jan '14

Hi all, time is moving fast, and I want to start some initial discussion and planning for OsmoDevCon 2014. There are basically four questions which I'm raising below. Please provide your feedback to the osmocom-event-orga mailing list only, to avoid cross-posting over all the project lists. = Who? = My intention is to keep it an 'active developer/contributer only' event, like we had it before. I would also want to keep the group relatively small, to keep the 'Osmocom family' atmosphere. If desired, we could have one half or full day of public prsentations in a larger auditorium, but the developer meeting should be a close group, as known so far. = Where? = If we keep the number of attendees within the same range as this year, then I'm sure we could again hold it at the same venue. I know it is not perfect, but it is a place that we have access to, 24 hours per day, and free of cost for community projects like osmocom.org. If the community wants a larger event, then this is something that would require more funds and much more time organizing. And that is something that I personally could not offer to take care of, sorry. I'm happy to attend and support any larger events, but I'm unable to take care of fundraising and venue research. = When? = Q1/2014. In January, I'm not aware of any 'blocker' events. February, there is Fosdem (Feb 1 + Feb 2), and MWC from Feb 24 through Feb 27. In March there is CeBIT (March 10-14) and Easter holidays (with EasterHegg March 17-21). Did I miss any other FOSS / mobile event that might clash in Q1? So my preference woudl be to do it either late January (23-26) or in February (6-9 or 13-16). Any preferences regarding preferred schedule? Once we have some concencus here on the list [and we want to do it in the same size / venue], I'll talk to IN-Berlin. = What? = I think that question is easy to answer, if we have the above three figured out... There's no shortage of topics, I suppose. You can start adding your suggestions to http://openbsc.osmocom.org/trac/wiki/OsmoDevCon2014 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)

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miri_fm scanning speed
by Sdr Guru 31 Dec '13

31 Dec '13

Hi The test results: miri_fm 543-723 step/sec - 65% CPU load (800MHz Intel) rtl_fm 7,65 step/sec - 6,3% CPU load (800MHz Intel) SG

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Bandwidth
by IZ8MBW Fabio 27 Dec '13

27 Dec '13

Hi again. I would like to stream the RTL SDR over the Internet. My Internet connection is 1 Megabit in upload (much less than a LAN connection). Is there a way to decrase or cap the bandwith of rtl_tcp? In others words: is possible for example limit the audio stream on a bandwith of 300 Hz to 3400 Hz? Thanks. Fabio, IZ8MBW

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Re: Bandwidth
by IZ8MBW Fabio 26 Dec '13

26 Dec '13

Hi Jay, rtl_fm can be used like rtl_tcp ? Can I use SDR Sharp (SDR#) on a Windows 7 PC (Client side) to connect on the RTL SDR on the Raspberry Pi (Server side) like rtl_tcp? 73 Fabio, IZ8MBW www.iz8mbw.net >________________________________ > Da: Jay Bougie <jaybougie(a)gmail.com> >A: IZ8MBW Fabio <iz8mbw(a)yahoo.it> >Inviato: Lunedì 23 Dicembre 2013 23:33 >Oggetto: Re: Bandwidth > > > >Have you checked out rtl_fm yet? >May just do the trick for your setup. >On Dec 23, 2013 5:10 PM, "IZ8MBW Fabio" <iz8mbw(a)yahoo.it> wrote: > > >>Hi again. >>I would like to stream the RTL SDR over the Internet. My Internet connection is 1 Megabit in upload (much less than a LAN connection). >>Is there a way to decrase or cap the bandwith of rtl_tcp? >>In others words: is possible for example limit the audio stream on a bandwith of 300 Hz to 3400 Hz? >> >>Thanks. >> >>Fabio, IZ8MBW >> >> >> > >

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RTL2832U on Raspberry Pi
by IZ8MBW Fabio 23 Dec '13

23 Dec '13

Hi. I'm trying to install OSMOSdr on a Raspberry Pi. I'm following this guide: http://www.hamradioscience.com/raspberry-pi-as-remote-server-for-rtl2832u-s… After installing I try to test the RTL2832 USB SDR but I have this error: root@raspberrypi:~/rtl2832/rtl-sdr/build# rtl_test Found 1 device(s): 0: Generic RTL2832U OEM Using device 0: Generic RTL2832U OEM Kernel driver is active, or device is claimed by second instance of librtlsdr. In the first case, please either detach or blacklist the kernel module (dvb_usb_rtl28xxu), or enable automatic detaching at compile time. usb_claim_interface error -6 Failed to open rtlsdr device #0. This is my lsmod: root@raspberrypi:~# lsmod Module Size Used by tun 18459 2 i2c_dev 5557 0 w1_therm 2921 0 w1_gpio 2363 0 wire 24832 2 w1_gpio,w1_therm cn 4783 1 wire snd_bcm2835 16165 0 evdev 9419 1 r820t 16279 1 rtl2832 8020 1 snd_soc_bcm2708_i2s 5474 0 regmap_mmio 2806 1 snd_soc_bcm2708_i2s dvb_usb_rtl28xxu 14333 0 dvb_usb_v2 14860 1 dvb_usb_rtl28xxu rc_core 16313 3 dvb_usb_rtl28xxu,dvb_usb_v2 rtl2830 7378 1 dvb_usb_rtl28xxu snd_soc_core 131268 1 snd_soc_bcm2708_i2s dvb_core 92797 3 rtl2830,rtl2832,dvb_usb_v2 regmap_spi 1897 1 snd_soc_core snd_pcm 81593 2 snd_bcm2835,snd_soc_core snd_page_alloc 5156 1 snd_pcm regmap_i2c 1645 1 snd_soc_core snd_compress 8076 1 snd_soc_core snd_seq 53769 0 snd_timer 20133 2 snd_pcm,snd_seq snd_seq_device 6473 1 snd_seq leds_gpio 2059 0 led_class 3688 1 leds_gpio snd 61291 7 snd_bcm2835,snd_soc_core,snd_timer,snd_pcm,snd_seq,snd_seq_device,snd_compress i2c_bcm2708 3949 0 This is a portion of /var/log/messages . . . Dec 23 13:15:06 raspberrypi kernel: [ 2.369348] usb 1-1: new high-speed USB device number 2 using dwc_otg Dec 23 13:15:06 raspberrypi kernel: [ 2.377867] Indeed it is in host mode hprt0 = 00001101 Dec 23 13:15:06 raspberrypi kernel: [ 2.387121] devtmpfs: mounted Dec 23 13:15:06 raspberrypi kernel: [ 2.399736] Freeing unused kernel memory: 144K (c0572000 - c0596000) Dec 23 13:15:06 raspberrypi kernel: [ 2.590087] usb 1-1: New USB device found, idVendor=0424, idProduct=9512 Dec 23 13:15:06 raspberrypi kernel: [ 2.599431] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 Dec 23 13:15:06 raspberrypi kernel: [ 2.609377] hub 1-1:1.0: USB hub found Dec 23 13:15:06 raspberrypi kernel: [ 2.615786] hub 1-1:1.0: 3 ports detected Dec 23 13:15:06 raspberrypi kernel: [ 2.899604] usb 1-1.1: new high-speed USB device number 3 using dwc_otg Dec 23 13:15:06 raspberrypi kernel: [ 3.009979] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00 Dec 23 13:15:06 raspberrypi kernel: [ 3.018605] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 Dec 23 13:15:06 raspberrypi kernel: [ 3.047105] smsc95xx v1.0.4 Dec 23 13:15:06 raspberrypi kernel: [ 3.124437] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-bcm2708_usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:30:43:fd Dec 23 13:15:06 raspberrypi kernel: [ 3.229549] usb 1-1.3: new high-speed USB device number 4 using dwc_otg Dec 23 13:15:06 raspberrypi kernel: [ 3.352535] usb 1-1.3: New USB device found, idVendor=0bda, idProduct=2838 Dec 23 13:15:06 raspberrypi kernel: [ 3.365766] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Dec 23 13:15:06 raspberrypi kernel: [ 3.375070] usb 1-1.3: Product: RTL2838UHIDIR Dec 23 13:15:06 raspberrypi kernel: [ 3.381218] usb 1-1.3: Manufacturer: Realtek Dec 23 13:15:06 raspberrypi kernel: [ 3.391654] usb 1-1.3: SerialNumber: 00000001 Dec 23 13:15:06 raspberrypi kernel: [ 5.123693] bcm2708_i2c_init_pinmode(0,0) Dec 23 13:15:06 raspberrypi kernel: [ 5.249498] bcm2708_i2c_init_pinmode(0,1) Dec 23 13:15:06 raspberrypi kernel: [ 5.255625] bcm2708_i2c bcm2708_i2c.0: BSC0 Controller at 0x20205000 (irq 79) (baudrate 100k) Dec 23 13:15:06 raspberrypi kernel: [ 5.468627] bcm2708_i2c_init_pinmode(1,2) Dec 23 13:15:06 raspberrypi kernel: [ 5.545257] bcm2708_i2c_init_pinmode(1,3) Dec 23 13:15:06 raspberrypi kernel: [ 5.614064] bcm2708_i2c bcm2708_i2c.1: BSC1 Controller at 0x20804000 (irq 79) (baudrate 100k) Dec 23 13:15:06 raspberrypi kernel: [ 6.451707] usb 1-1.3: dvb_usb_v2: found a 'Realtek RTL2832U reference design' in warm state Dec 23 13:15:06 raspberrypi kernel: [ 6.510309] usbcore: registered new interface driver dvb_usb_rtl28xxu Dec 23 13:15:06 raspberrypi kernel: [ 6.552127] usb 1-1.3: dvb_usb_v2: will pass the complete MPEG2 transport stream to the software demuxer Dec 23 13:15:06 raspberrypi kernel: [ 6.575184] DVB: registering new adapter (Realtek RTL2832U reference design) Dec 23 13:15:06 raspberrypi kernel: [ 6.614879] bcm2708-i2s bcm2708-i2s.0: Failed to create debugfs directory Dec 23 13:15:06 raspberrypi kernel: [ 6.639092] usb 1-1.3: DVB: registering adapter 0 frontend 0 (Realtek RTL2832 (DVB-T))... Dec 23 13:15:06 raspberrypi kernel: [ 6.693199] r820t 2-001a: creating new instance Dec 23 13:15:06 raspberrypi kernel: [ 6.721703] r820t 2-001a: Rafael Micro r820t successfully identified Dec 23 13:15:06 raspberrypi kernel: [ 6.744416] Registered IR keymap rc-empty Dec 23 13:15:06 raspberrypi kernel: [ 6.755520] input: Realtek RTL2832U reference design as /devices/platform/bcm2708_usb/usb1/1-1/1-1.3/rc/rc0/input0 Dec 23 13:15:06 raspberrypi kernel: [ 6.785036] rc0: Realtek RTL2832U reference design as /devices/platform/bcm2708_usb/usb1/1-1/1-1.3/rc/rc0 Dec 23 13:15:06 raspberrypi kernel: [ 6.808934] usb 1-1.3: dvb_usb_v2: schedule remote query interval to 400 msecs Dec 23 13:15:06 raspberrypi kernel: [ 6.840041] usb 1-1.3: dvb_usb_v2: 'Realtek RTL2832U reference design' successfully initialized and connected Dec 23 13:15:06 raspberrypi kernel: [ 10.489768] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) Dec 23 13:15:06 raspberrypi kernel: [ 10.929880] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) . . . Any idea to how to solve? Many thanks!! 73 Fabio, IZ8MBW www.iz8mbw.net

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