osmocom-sdr

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906 discussions

Why is there Sleep() in rtl_fm?
by Alan Corey 02 Jan '13

02 Jan '13

Is this from Windows or something? In unix it's sleep, not Sleep, and it only takes ints or something similar. I have a native (OpenBSD) usleep so I ifdefed: #ifdef _WIN32 #define usleep(x) Sleep(x/1000) #endif It didn't affect my problem but it made me feel better. Alan ----- Radio Astronomy - the ultimate DX

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Trying to use rtl_fm, etc
by Alan Corey 02 Jan '13

02 Jan '13

With rtl_fm, I get a tiny burst of audio about once a minute. My dongle is a vendor ID 0x0bda, product ID0x2838 from http://www.amazon.com/gp/browse.html?ie=UTF8&marketplaceID=ATVPDKIKX0DER&me… I did: rtl_fm -f 88500000 - | play -t raw -r 24k -e signed-integer -b 16 -c 1 -V1 - I got: Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000013 Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Found Rafael Micro R820T tuner -: (raw) Encoding: Signed PCM Channels: 1 @ 16-bit Samplerate: 24000Hz Replaygain: off Duration: unknown In:0.00% 00:00:00.00 [00:00:00.00] Out:0 [ | ] Clip:0 Oversampling input by: 42x. Oversampling output by: 1x. Buffer size: 8.13ms Tuned to 88752000 Hz. Sampling at 1008000 Hz. Output at 24000 Hz. Exact sample rate is: 1008000.009613 Hz Tuner gain set to automatic. In:0.00% 00:00:00.68 [00:00:00.00] Out:16.4k [ =====|===== ] Clip:0 ^CSignal caught, exiting! The dongle works if I boot into Windows, but in OpenBSD I can't get anything out of it. I'm still trying to get dependencies for Gnuradio together. The only odd thing is that being OpenBSD, there's no -lrt when I link. Those functions are built into something else so I compile without the -lrt. There isn't an -lrt library. I've tried writing little scripts to run it so I do it consistently. My wide FM one: #!/bin/sh rtl_fm -W -l 0 -f 88500000 - | play -t raw -r 32000 -e signed-integer -b 16 -c 1 -V4 - Narrow: #!/bin/sh rtl_fm -N -l 0 -f 162550000 - | play -t raw -r 32k -e signed-integer -b 16 -c 1 -V4 - I've played with various options. If I use -R it runs for a long time with lots of data by Sox's meter, but I don't hear anything. If I pipe it to a file (without -R) the file is very small and grows slowly, not what I would expect from audio. I just grabbed a fresh copy by git yesterday but it works about the same. A fresh run: freebie# rtl_fm -N -f 162550000 - | play -t raw -r 32k -e signed-integer -b 16 -c 1 -V 4 - Found 1 device(s): play: SoX v14.3.2 0: Realtek, RTL2838UHIDIR, SN: 00000013 Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Found Rafael Micro R820T tuner Oversampling input by: 42x. Oversampling output by: 1x. Buffer size: 8.13ms Tuned to 162802000 Hz. Sampling at 1008000 Hz. Output at 24000 Hz. Exact sample rate is: 1008000.009613 Hz Tuner gain set to automatic. Signal caught, exiting! I don't have much idea what's going on, but I'm tempted to try opening it from a pipe (in C) to see if I can capture anything more. Alan ----- Radio Astronomy - the ultimate DX

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Remote SDR# connection to Ham-It-Up HF Converter using RTL-SDR/TCP - Receiver is Deaf
by KD9GN 01 Jan '13

01 Jan '13

Happy New Year to Everyone .... I am thinking this may be more of an issue with rtl_tcp than with the client software (SDR#) so I thought I would throw this out there and see if anyone has any ideas. I have a Ham-it-Up up converter connected to an EZcap 668 (e4000) dongle and am using a random length long wire antenna all connected on a remote linux server (with minimal OS install) where I am running rtl_tcp. I am starting rtl_tcp using the following command: rtl_tcp -a 192.168.110.220 -p 1236 -d 2 When I connect to the remote dongle/converter using SDRSharp with RTL-USB/TCP I get nothing but static / noise. If I put the converter in bypass mode, then SDRSharp and my dongle perform with the typical performance I have experienced in the past. If I move the same dongle and up converter combo to the same pc running SDRSharp and connect to the dongle using RTL-SDR/USB I am able to receive many HF signals, as one would expect. For example, CHU Canada, WWV, some local CB radio chatter and even our local airport's LF beacon at 329 KHZ. I also tried starting rtl_tcp with the -g option and setting a gain to try to match the gain options available under RTL-SDR/USB but that had no effect. I am just wondering if I am not finding the correct settings so this will work or if this is an issue with rtl_tcp? BTW: I actually have two other Ezcap 668's running simultaneously on the remote linux server as device 0 / port 1234 and device 1 / port 1235 working just fine when connected to other remote instances of SDR Sharp. 73's - Dave KD9GN

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RTL2832
by ab ni 01 Jan '13

01 Jan '13

Hi, Does anyone technical documentations about RTL2832U ? soso

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Re: Direct sampling mode and rtl_xxx
by Sdr Guru 31 Dec '12

31 Dec '12

On Mon, Dec 31, 2012 at 2:02 AM, Alan Corey <alancorey(a)yahoo.com> wrote: > Some of them have a -R option for raw, I think that's what it does (rtl_fm > anyway). > This is a different topic. raw = no demodulation About "Direct sampling mode" https://groups.google.com/forum/#!topic/ultra-cheap-sdr/cG988R1D8uE SG > > Any documentation on this set of programs would be a good thing, other > than looking in the code or using --help. > > Alan > > > ----- > Radio Astronomy - the ultimate DX > > ------------------------------ > *From:* Sdr Guru <sdrguru1(a)gmail.com> > *To:* osmocom-sdr(a)lists.osmocom.org > *Sent:* Sunday, December 30, 2012 5:39 PM > *Subject:* Direct sampling mode and rtl_xxx > > Hi > > Is it possible to use rtl_fm, rtl_sdr and rtl_tcp in "Direct sampling > mode" > > SDR Guru > > > >

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rtl-sdr over multicast & multiple decoders
by James Sharp 31 Dec '12

31 Dec '12

I've been playing around with rtl-sdr as a way to stream trunking radio and air band traffic. I've done a bit of research and found people who are using multiple dongles, one to digest the control channel and one or more to tune and receive the voice channels as the talk groups come and go. They're also using multiple dongles and/or squelch scanning to stream airband signals Around here, all of the channels of the trunking system as well as all of the "interesting" fit inside the bandwidth of a dongle running at 3.6Msps. So, my question is this: Would it not be more efficient to have a single tuner dongle outputting all of its samples over multicast (or into a shared memory segment for that matter, if you want to stay on the same host) and then having a bunch of decoder processes listening to the samples and decoding what they need out of them?

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Direct sampling mode and rtl_xxx
by Sdr Guru 30 Dec '12

30 Dec '12

Hi Is it possible to use rtl_fm, rtl_sdr and rtl_tcp in "Direct sampling mode" SDR Guru

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decode raw
by Vitaliy Kulchevych 21 Dec '12

21 Dec '12

Hi, all! I want parse and decode raw data from my sdr device. I have RTL2832 based DVB-T receiver. I want get data from receiver via rtl-sdr sotware, parse and decode, and sent completed data through websocket to client in browser. Where I can find description of returning data from rtl_sdr, rtl_tcp. Specs, docs? Or what is the best way to do something like this my idea? Thanks! -- live free or die;

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Exceptionally Hard & Soft Meeting,exploring the frontiers of open source and DIY,Berlin, December 28-30 2012
by Andrea Montefusco 21 Dec '12

21 Dec '12

Maybe I lost some previous message, but I don't remember to have already seen that here. Anyway... From http://ehsm.eu/index.html: Harald Welte will present the Osmocom project he founded. In particular, there will be OsmocomBB, a free software GSM stack evolved enough to actually make phone calls and send SMS (plus all the possible explorations of the GSM system), and OsmoSDR, a small-size, low-cost software defined radio device. *am* --------------------------------------------------------- Andrea Montefusco iw0hdv http://www.montefusco.com tel: +393356992791 fax: +390623318709 ---------------------------------------------------------

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Information about the sampling rate of the RTLSDR driver
by frederic.evennou＠orange.com 17 Dec '12

17 Dec '12

Hello, I am testing a DVB-T USB key including the Elonics E4000 chipset and I want to check the sampling rate of this card. I set up the sampling rate at 2.048 Ms/s (rtlsdr_set_sample_rate), and my storing buffer is 8*1024 bytes, so I expect receiving 1024 I/Q samples every 500 microseconds. I am using the rtlsdr_read_async function to read the samples. Unfortunately the loop in my program indicates that 8*1024 bytes are read every 2 milliseconds. I am using the gettimeofday function to measure the time in microseconds. Does this result mean that the best I can do is to read some samples every 2 ms at 2.048 Ms/s. This would mean that I am missing 1.5 ms of signal. Is that correct or I am doing something wrong ? Thanks for your help. Frederic _________________________________________________________________________________________________________________________ Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration, France Telecom - Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. This message and its attachments may contain confidential or privileged information that may be protected by law; they should not be distributed, used or copied without authorisation. If you have received this email in error, please notify the sender and delete this message and its attachments. As emails may be altered, France Telecom - Orange is not liable for messages that have been modified, changed or falsified. Thank you.

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