osmocom-sdr July 2013

osmocom-sdr@lists.osmocom.org

12 participants
15 discussions

by Pawel Janowski

Hello its great idea ! I think the next step (small for man big form mankind) should be decoding (based on rtl_fm) APRS messages and putting into APRS-IS Servers ! with regards Pawel, SQ7MRU http://sq7mru.blogspot.com/

11 years, 11 months

Re: ACARS decoder using rtl-sdr

by Adam Nielsen

> Hi, > > The grab connection doesn't work :( > > 73, Murat TA1DB If you're running a recent version of Linux, it will load DVB drivers so you can watch TV with the device. You'll have to unload these to make the device available for use: sudo rmmod dvb_usb_rtl28xxu rtl2832 e4000 (assuming an e4000 device, not sure what module to unload for other tuners, lsmod will tell you.) Cheers, Adam.

11 years, 11 months

Possible bug in device removal detection code in librtlsdr.c

by Alexey Kruglov

Hi. Device removal detection code in _libusb_callback in librtlsdr.c may be buggy. Every time we get any status other than LIBUSB_TRANSFER_COMPLETED (including LIBUSB_TRANSFER_ERROR) the code doesn't resubmit current buffer, and we get the real number of working buffers decreased by one. If that number goes down to 0, rtlsdr_read_async() will hang. Linux version tries to control it by counting the number of LIBUSB_TRANSFER_ERROR buffers that came in row in dev->xfer_errors. But if we already have _one_ failed buffer during the whole transfer up to the moment, that counter will never reach dev->xfer_buf_num. So it seems more straightforward to 1. count the failed buffers and rtlsdr_cancel_async() when it reaches 0 or some sensible threshold, and 2. maybe resubmit some kinds of the failed buffers other than LIBUSB_TRANSFER_COMPLETED, if it makes sense. I am not a libusb guru and it's not well documented in this part, so I am not sure about my second point. Hoping some librtlsdr developers will appear on this list. -- GPG fp: 6DFA 1186 7576 DE60 6CCB EB39 AD81 1733 EEBB 970A

11 years, 11 months

Delay after rtlsdr_cancel_async

by Alexey Kruglov

Hi. I noticed there is a 1 second delay in librtlsdr between calling rtlsdr_cancel_async and releasing from rtlsdr_read_async. I'm writing a radio scanner and this delay limits scanning speed considerably. I tracked the delay down to this piece of code in librtlsdr.c: while (RTLSDR_INACTIVE != dev->async_status) { r = libusb_handle_events_timeout(dev->ctx, &tv); [...] if (RTLSDR_CANCELING == dev->async_status) { next_status = RTLSDR_INACTIVE; [...] if (dev->dev_lost || RTLSDR_INACTIVE == next_status) { >>>> libusb_handle_events_timeout(dev->ctx, &tv); break; } The marked line is almost always(?) invoked when all the events are already processed, hence it blocks for tv = 1 second. In fact I don't understand what this `if' is supposed to do at all. I tried to modify this line by changing the delay to 0 making it a non-blocking call (leaving the timeout of 1 sec for the former libusb_handle_events_timeout call). This worked with my project and the 1 second delay disappeared. So, I suppose, it's better to either a) remove the whole `if' or b) make the latter libusb_handle_events_timeout non-blocking as I did. I checked that b) works for me, and didn't test a) yet. The question is: what that `if (dev->dev_lost ...' is supposed to do? And the two possible fixes for 1 second delay bug depending on the answer are (diffs): === 1630a1631 > struct timeval tv_nb = { 0, 0 }; 1696c1697 < libusb_handle_events_timeout(dev->ctx, &tv); --- > libusb_handle_events_timeout(dev->ctx, &tv_nb); === === 1694,1698d1693 < < if (dev->dev_lost || RTLSDR_INACTIVE == next_status) { < libusb_handle_events_timeout(dev->ctx, &tv); < break; < } === -- GPG fp: 6DFA 1186 7576 DE60 6CCB EB39 AD81 1733 EEBB 970A

11 years, 11 months

Anybody running gr-osmosdr or gr-baz under Windows?

by Murat Toloğlu

Hi All, After more than 2 weeks of endless trials to build, install and run gr-osmosdr and/or gr-baz in Windows 7 to have an RTL2832 source in GNU Radio - GRC without success I really wander if anybody exists and running these programs under Windows? Do you know anybody who succeeded to build and install gr-osmosdr and/or gr-baz in Windows? Regards, Mu

11 years, 11 months

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osmocom-sdr July 2013