osmocom-sdr

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906 discussions

Recent librtlsdr and example program don't work
by Andrea Montefusco 09 May '12

09 May '12

After about a month, I refreshed the local git sandbox but I was not anymore able to receive any sample, even with the test program. I am using a Terratec NOXON DAB/DAB+ USB dongle (rev 1) on Ubuntu 11.10 x86_64 . ./rtl_sdr - Found 1 device(s): 0: Terratec NOXON DAB/DAB+ USB dongle (rev 1) Using device 0: Terratec NOXON DAB/DAB+ USB dongle (rev 1) Found Fitipower FC0013 tuner Tuned to 100000000 Hz. Tuner gain set to -1.000000 dB. Reading samples in async mode... but I can get no output. *am* --------------------------------------------------------- Andrea Montefusco iw0hdv http://www.montefusco.com tel: +393356992791 fax: +390623318709 ---------------------------------------------------------

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Re: OT: usb hub power switching (Re: Recent librtlsdr and example program don't work)
by Dieter Spaar 09 May '12

09 May '12

Hello Peter, On Tue, 8 May 2012 23:47:33 +0200, "Peter Stuge" <peter(a)stuge.se> wrote: > > Yes, I haven't seen it available in any userspace API on any system. :\ > > It may be possible to send the request to the hub from userspace, but > I haven't tried it. Older Windows Version (before Vista) had IOCTL_USB_HUB_CYCLE_PORT to perform a power cycle. I think there is still a way in newer version too, If I am not wrong the WHQL driver testings tools do perform USB power cycles frequently when testing USB devices. Of course the above is only relevant if you care about Windows ;-) Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de

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RTL2832 questions
by Jeff Gustafson 08 May '12

08 May '12

Hi all, First of all, props to the person that found out how to put the RTL chip into a SDR compatible mode! I've been wanting to play around with SDR and, specifically, P25 for a while now. Finally an inexpensive way to get my feet wet. My question is probably a bit of a noob question. I have successfully received a broadcast FM radio station with the RTL dongle. The problem is that I can't seem to decode anything else. I tried to receive some ham radio (NFM) transmissions from my radio and I didn't get any sound. The white noise blanked out, the scope in gnuradio spiked up, but no real demodulation. Would someone be willing to share a .grc file they know will decode NFM with the gr-osmosdr/rtl-sdr driver? I tried taking some files that used the USRP driver and swapping out the USRP driver with the osmosdr/rtl driver, but no go. Could it be that I don't have all the sampling rates and decimation rates set correctly? ...Jeff

1 1

Patch for Compro U680F support.
by Marek Kroemeke 03 May '12

03 May '12

Hi guys, Unclear in what format you require patches - but I bought Compro U680F 2 days ago, it has the E4000 chipset and it only required adding usb id in, so as requested in docs - sending a small "patch" that makes it work :-) regards, Marek Kroemeke

2 1

Detach kernel driver
by Michal Demin 24 Apr '12

24 Apr '12

Hello, Attached are 2 patches: 1 - Try to detach kernel driver from device, when kernel driver present. 2 - add rtl_tcp binary to gitignore. Michal Demin

2 5

RTL-SDR ghost signal at center frequency & hangs in GR spectrum view
by Benedikt Heinz 20 Apr '12

20 Apr '12

Hi everyone, can someone explain to me, what the origin of the ghost signal close to center frequency is? It can be seen at [1] and [2] - both are EzTV668 with no antenna connected. It seems to me, that the higher the frequency, the more one can see the "burst-like" nature of this signal. Is this some mixer artefact from the E4k tuner? The best workaround is probably tuning a bit off the actual target frequency and using frequency xlate? Also, in [3] (german) the blind spot at 0Hz due to the coupling capacitors between E4k & RTL is mentioned. Is it possible to replace the capacitors with 0-Ohm resistors to work around this issue, or will this cause other unwanted side-effects? Or does this make no sense at all since one should always tune a bit off and use xlate due to the ghost signal? I guess it should also be possible (w/ some hot glue & wires) to insert some jumpers (like OsmoSDR) instead, so one can use the ADCs directly for LF/MF with some extra analog stuff? Regarding the OsmoSDR source - I also gave the RTL-source from gr-baz a try and noticed, that with averaging enabled in the spectrum view in GR, the top-block GUI usually won't react to user input any longer when using OsmoSDR, but this doesn't happen with the gr-baz RTL source, although I used the same sample rate in both cases. Does anyone understand why it doesn't hang with the gr-baz source? Thanks for your answers! Regards, hunz [1] http://hackdaworld.org/~hunz/rtl-sdr/wo_ant_2m_osmo.png [2] http://hackdaworld.org/~hunz/rtl-sdr/wo_ant_70cm_osmo.png [3] http://www.mikrocontroller.net/topic/253371#2610540 -- Benedikt Heinz hunz(a)jabber.berlin.ccc.de

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OsmoSDR - they're on final approach
by Christian Daniel -- maintech GmbH 19 Apr '12

19 Apr '12

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi everybody, just as a short heads up: The new boards have arrived and the first batch of 20 is assembled. Since we did changes to the layout we will verify them before we do the other 80. This should take no more than a few days. Stay tuned! BTW: The new pre-amp/lnb really does add 18dB :) Best regards, Christian - -- - --------------------------------------------------- | maintech # Dipl. Inf (FH) Christian Daniel | | GmbH ### Otto-Hahn-Str. 15 · D-97204 Höchberg | - --------------------------------------------------- | AG Würzburg, HRB 8790 Tax-ID DE242279645 | - --------------------------------------------------- | http://www.maintech.de cd(a)maintech.de | - --------------------------------------------------- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPkBrEAAoJEHkgzUIsAWritBgH/RqDZuLRLQ/22msTdvZ+EIqk 6Y98xDBrDcXSkTSsFBQvLwdKANUxxi3dVvTjknBw3lnrWzT8fo2uVMg97c/R6Eov fGOvALbXckgrmvz0n/IZdROu8x38zs/ro0uweN0oxb14+U/2CW5VVeJusqcQoBL6 Ug4XAtzXpyR04pmjjq6jzxtsmsXuv42KToG7R9UvkiNz8WXhxlaaUmA+ccJGM+8+ FCITzYY9ZMfFo2IekXDGkZNsKwux37B8cQxYIlcSlPxlSrPzusFyyqEq2AmM1iIn SbuRnmjzeUQbsgGVINmVP1B3EDOczeYWyeKC/5myXbr+Ogpp9/PD9K9aJG/sKYM= =KY1W -----END PGP SIGNATURE-----

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Real-time DRM+ receiver chain using the NOXON stick
by Feilen, Michael 19 Apr '12

19 Apr '12

Dear Osmocon-SDR People, Thank you so much for providing the information on the RTL-SDR USB sticks on your webpage! I've used the stick to get a DRM+ receiver implementation running and the stick seems to work quite well: http://www.youtube.com/watch?v=zeGs7CQlvRg I've had to twiddle around with the tuner parameters of the FC0013 to get it running stable. However, I've never reached more than 25 dB SNR for the in-band OFDM signal (which has a bw of 100 kHz and I'm resampling from 1 MS/s to 120 kS/s). I wonder if the tuner is the limiting factor or the RTL chip. With a resolution of 8 bit, I would have expected more. Hmm, maybe it's the phase noise of the tuner or the IQ correction routines of the RTL chip? Has anybody of you guys a meaningful measure for the quality of the different tuners for the RTL stick? I know that the E4000 supports a higher bandwidth but does it provide a better IQ signal with less distortion? Cheers, Michael

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rtl-sdr with Compro Videomate U620F
by Simeon Miteff 12 Apr '12

12 Apr '12

Hi All The Compro Videomate U620F has the magic RTL2832+E4000 combination. rtl-sdr recognises it with the patch: https://gist.github.com/2362895 Regards, Simeon.

2 1

Buffer length in rtlsdr_wait_async
by Andrea Montefusco 08 Apr '12

08 Apr '12

Hi all, together with Oliver DL6KBG (that really provides me with all the hardware needed, thanks !), we are attempting to write a server suitable for use with ghpsdr3-alex SDR software. A first attempt using the a home built code was quite successfully, albeit some defect is yet there. Now we are trying to use the librtlsdr: first off, many thanks to developers. We are stucked into rtlsdr_wait_async that is using a fixed quite large buffer, as per #define BUF_LENGTH (16 * 16384) now that is quite inconvenient in ghpsdr3-alex, because, at low sample rate (250000) we use, we are unable to cope with the large delay that this large buffer introduces. So, just as crude workaround, we simply patched the value into the lib. What would be ideal is an additional parameter in rtlsdr_wait_async that allow us to reduce the buffer to a more suitable size for our needs. Thanks in advance *am* --------------------------------------------------------- Andrea Montefusco iw0hdv http://www.montefusco.com tel: +393356992791 fax: +390623318709 ---------------------------------------------------------

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