osmocom-sdr January 2018

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gr-osmosdr: add clock_source= parameter
by Michael Loeffler 25 Mar '21

25 Mar '21

Hello, the attached patch allows to set the clock_source on uhd devices in programs like gqrx. Bye

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SDRPlay in gr-osmosdr
by Jeff Long 26 Jan '18

26 Jan '18

Here is a PyBOMBS recipe file that pulls gr-osmosdr from my sdrplay2 branch. If anyone would like to try out this support with a PyBOMBS build, this would be the easiest way. Best to build everything from scratch, but you can remove the src/gr-osmosdr directory, do a pybombs fetch/rebuild if you're comfortable with that. The SDRplay SDK v2.11 is required, and should be installed before gr-osmosdr is rebuilt. The ENABLE_NONFREE flag is turned on for this build. This is just for testing, so I can get some feedback. Hopefully, this will go into the gr-osmosdr master at some point. It "works for me". Note that the gains on SDRplay are actually attenuations, so they appear backward. The LNA attenuation steps on RSPs are frequency dependent, so I gave up trying to make them look like gains. My main use case is GQRX, and that way was even more confusing. There is a GRC sdrplay source that is a little less generic than the osmocom source. There are probably ways to repackage this so it can be distributed freely, but I'll address that if there's more interest. The SDK include file is redistributable and its terms seem to be compatible with GPL. The shared object can be dynamically loaded over a placeholder library that does nothing. Yes, that's hackish and it would be better to have everything free.

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[gr-osmosdr] Patch: Update SDRplay Support
by Jeff Long 15 Jan '18

15 Jan '18

SDRplay support, rewritten, supporting RSP1, RSP1A, and RSP2 Requires ENABLE_NONFREE=yes. Requires SDRplay's SDK v2.11 to be installed by the user. In the future, if there is a way to redistribute mirsdrapi-rsp.h from the SDK, that problem could be addressed using a shim library that looks for /usr/local/lib/libmirsdrapi-rsp.so at runtime.

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Looking for help decoding Pulse Interval Width Modulation
by Adam Callis 14 Jan '18

14 Jan '18

Good afternoon, I am a complete noob playing with my YardStick one and HackRf one. I am working a signal that I am fairly certain is using pulse interval encoding and I am having a heck of a time understanding how to turn the NRZ 1's and 0's into the Pulse Interval. The closest thing I have seen is how RFID uses pulse interval encoding but I don't think that is the same thing. I started by recording in osmocom_fft I then used inspectrum to extract symbols and found that most symbols were 1 unit in inspectrum, but there were a few places where there were 2 or 4 in a row of high or low. Once I exported the symbols I was able to generate a bit string of 1's and 0's representing highs and lows. I was able to identify the preamble and what I think is the sync word, but that's where I get lost. I have seen many examples where people take 3 bits and assume that say 001 is a 0 and 011 is a 1n a PWM model but nothing I seem to do seems to work to uncover the PIE encoding and was hoping someone out there could point me in the right direction. Thanks, Adam Sent from my iPad

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modify rtl-sdr.h to lower the sample rate at 125000
by Olivier SCHMITT 08 Jan '18

08 Jan '18

Hello dear RTL-SDR community, I just whant to ask if it's possible to modify rtl-sdr.h to lower the admissible sample rate. I am currently using 8 dongle successfully but would like to use 12 dongle simultaneously with software (rtlsdr-wsprd) to decode wspr signals. This one uses the library rtl-sdr. I would therefore like to be able to use sampling frequencies lower than 250000. Thanks in advance!

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limitations of using multiple RTL-SDR dongles simultaneously
by Olivier SCHMITT 08 Jan '18

08 Jan '18

Hello dear RTL-SDR users, I whant to use multiples dongles as array for decode wspr. My problem is that I can not use more than 4 USB dongle simultaneously. I check with usbmon, each dongle uses 500kbits / s around. So I am far from the maximum bandwidth allowed by usb 2. I tried using a USB switch with external power supply but it does not work better. The default test performed is: #!/bin/bash for ((i=0;i<=4;i++)) do rtl_test -d $i -s 250000 & done First 4 is starting but last 5 doesent. And i whant to use more... Is this a limitation of the RTL-SDR library or the kernel driver? Do we have a solution to get around the problem? Thank you in advance for your valuable feedback.

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[PATCH] rtl_tcp: rtl_tcp_source_c.cc: Adds explicit cast
by Mike Morris 03 Jan '18

03 Jan '18

To prevent build errors on macOS 10.13.2 --- lib/rtl_tcp/rtl_tcp_source_c.cc | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/lib/rtl_tcp/rtl_tcp_source_c.cc b/lib/rtl_tcp/rtl_tcp_source_c.cc index ecdeee0..c962dd8 100644 --- a/lib/rtl_tcp/rtl_tcp_source_c.cc +++ b/lib/rtl_tcp/rtl_tcp_source_c.cc @@ -298,17 +298,17 @@ rtl_tcp_source_c::rtl_tcp_source_c(const std::string &args) : // set direct sampling struct command cmd; - cmd = { 0x09, htonl(direct_samp) }; + cmd = (struct command){ 0x09, htonl(direct_samp) }; send(d_socket, (const char*)&cmd, sizeof(cmd), 0); if (direct_samp) _no_tuner = true; // set offset tuning - cmd = { 0x0a, htonl(offset_tune) }; + cmd = (struct command){ 0x0a, htonl(offset_tune) }; send(d_socket, (const char*)&cmd, sizeof(cmd), 0); // set bias tee - cmd = { 0x0e, htonl(bias_tee) }; + cmd = (struct command){ 0x0e, htonl(bias_tee) }; send(d_socket, (const char*)&cmd, sizeof(cmd), 0); } @@ -567,7 +567,7 @@ bool rtl_tcp_source_c::set_gain_mode( bool automatic, size_t chan ) send(d_socket, (const char*)&cmd, sizeof(cmd), 0); // AGC mode - cmd = { 0x08, htonl(automatic) }; + cmd = (struct command){ 0x08, htonl(automatic) }; send(d_socket, (const char*)&cmd, sizeof(cmd), 0); _auto_gain = automatic; -- 2.15.1

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SDRplay rewrite w/RSP2
by Jeff Long 01 Jan '18

01 Jan '18

I picked up a SDRplay RSP2 recently, and the gr-osmosdr support needed some work. Here's a rewrite that works with RSP2 and has other improvements. When the RSP1A comes in, I'll finish support for that. No plans to pick up a RSP1, but someone can see if this works if interested. This was tested against the Nov 2017 binary blob. https://github.com/willcode/gr-osmosdr/tree/sdrplay2 ===== Complete rewrite of sdrplay support - Supports RSP2 - Will support RSP1A when hardware arrives - RSP1 is untested - Uses streaming callbacks instead of polling - Tuning, gain control imporoved, AGC supported - Better performance (one less layer of buffers)

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osmocom-sdr January 2018