Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

W dniu 28.06.2016 o 15:50, mle...@ripnet.com pisze: > > I just forked Keenerd's repo, which actually has support for turning > dither on/off in the API, but of course, gr-osmosdr has no support for it. > > My fork is: > > https://github.com/patchvonbraun/rtl-sdr > > Hi Marcus and all, I've

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

On 06/28/2016 06:25 AM, Piotr Krysik wrote: Hi Marcus, It's great to hear that there is interest in using the block. I can change how parameters are displayed but I don't have clear idea how to do this so the user experience with for a systems with 8+ inputs will be improved. I can separate RF

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

I just forked Keenerd's repo, which actually has support for turning dither on/off in the API, but of course, gr-osmosdr has no support for it. My fork is: https://github.com/patchvonbraun/rtl-sdr Also the difference in frequency resolution with dither on/off is very small--less than the

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

W dniu 28.06.2016 o 12:25, Piotr Krysik pisze: > W dniu 28.06.2016 o 03:31, Marcus D. Leech pisze: >> On 06/25/2016 04:25 PM, Piotr Krysik wrote: >>> W dniu 25.06.2016 o 01:56, Marcus D. Leech pisze: On 05/26/2016 04:09 AM, Piotr Krysik wrote: > Is there some good candidate that can be

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

W dniu 28.06.2016 o 03:31, Marcus D. Leech pisze: > On 06/25/2016 04:25 PM, Piotr Krysik wrote: >> W dniu 25.06.2016 o 01:56, Marcus D. Leech pisze: >>> On 05/26/2016 04:09 AM, Piotr Krysik wrote: Is there some good candidate that can be asked to do that? When I search for rtlsdr

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

On 06/25/2016 04:25 PM, Piotr Krysik wrote: W dniu 25.06.2016 o 01:56, Marcus D. Leech pisze: On 05/26/2016 04:09 AM, Piotr Krysik wrote: Is there some good candidate that can be asked to do that? When I search for rtlsdr driver the first page with actual source code is osmocom's site:

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

On 06/25/2016 04:25 PM, Piotr Krysik wrote: Hi Marcus, If it is possible to do estimate this frequency offset correctly (better than one would expect from normal measurement thanks to some a-priori knowledge like ~0.072Hz granularity that as you said might be there) - I can live with

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

W dniu 25.06.2016 o 01:56, Marcus D. Leech pisze: > On 05/26/2016 04:09 AM, Piotr Krysik wrote: >> Is there some good candidate that can be asked to do that? When I search >> for rtlsdr driver the first page with actual source code is osmocom's >> site: >> >> sdr.osmocom.org/trac/wiki/rtl-sdr >>

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

On 05/26/2016 04:09 AM, Piotr Krysik wrote: Is there some good candidate that can be asked to do that? When I search for rtlsdr driver the first page with actual source code is osmocom's site: sdr.osmocom.org/trac/wiki/rtl-sdr Maybe they have the maintainer who feels responsible for how this

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

A bias in the dither algorithm could explain that, which is why turning off dither clears up the problem. The drifting-out-of-lock problem is due to charge-pump current settings being too low in some cases. On 2016-05-26 11:47, Juha Vierinen wrote: > Would either of these issues in the rtlsdr

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Would either of these issues in the rtlsdr driver consistently tune the two dongles on slightly different frequencies, even if you ask them to tune to exactly the same frequency? This is what the problem seems to be. juha On Wed, May 25, 2016 at 10:35 AM, wrote: > There are

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

I was using a dongle with r820. juha > On May 25, 2016, at 23:27, Piotr Krysik wrote: > > Juha, > > What type of demodulator did you have in the dongles used for the test? > > -- > Piotr > > W dniu 25.05.2016 o 14:46, Juha Vierinen pisze: >> In my testing, this phase rate

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Is there some good candidate that can be asked to do that? When I search for rtlsdr driver the first page with actual source code is osmocom's site: sdr.osmocom.org/trac/wiki/rtl-sdr Maybe they have the maintainer who feels responsible for how this code works? I can try to correct this offset in

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Juha, What type of demodulator did you have in the dongles used for the test? -- Piotr W dniu 25.05.2016 o 14:46, Juha Vierinen pisze: > In my testing, this phase rate difference seemed constant and I could > simply calibrate it out by looking at the phase rate term estimated > from the phase

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

The AirSpy uses the R820T2 chip for the tuner, but a different sampling/DSP "engine". Yes, making the charge-pump and "dither" mods will help with phase-coherence. Somebody needs to "own" the rtlsdr driver, and merge in the last couple of years of field experience and branching that has gone

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Hi Marcus, I don't know much about AirSpy. Does it use the same demodulator chip as current RTL-SDR dongles? And does it mean that change to low level part of rtlsdr driver might help to get rid of that frequency offset? -- Piotr W dniu 25.05.2016 o 16:35, mle...@ripnet.com pisze: > > There

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

There are a couple of issues with the rtlsdr driver used by gr-osmocom in this regard: (A) The charge-pump loop current is too constrained for the higher frequencies (B) The "dither" option appears to have a bias that causes a (small) frequency offset. The driver that AirSpy uses fixes

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

That, or simply, the output clock VCO changes its reaction to the control voltage under certain circumstances (temperature, frequency) so much that the control loop loses the ability to reach stationary exactness (e.g. due to natural limits on the magnitude of the VCO voltage). These devices

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

In my testing, this phase rate difference seemed constant and I could simply calibrate it out by looking at the phase rate term estimated from the phase of the cross-correlated noise. The samples stay aligned for hours, so the issue is caused by the tuner or the DDC. One theory that I had was that

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Hi, > of the drift remains a mistery (probably due to the implementation of the PLL, > but I cannot understand why Phase Locked Loops would drift in Phase !). If the phase comparator is digital ( i.e. a XOR ) and the input clock is somewhat analog, the gate thresholds might vary depending on

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

>From our own experience with dual-dongle measurements, the phase drift seems to be strongly related to R820T(2) temperature. We reduced significantly the phase drift by gluing a large heat sink common to both chips on both dongles, without completely removing this effect (we aim at measurements

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Hi Juha, It wouldn't be as simple as it was for me as a developer and as it (hopefully) is for the end user without your hardware mod. Can you say something more about the residual center frequency difference? Where might it come from? I prepared little test of coherency between the receivers

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

This is awesome! I'll definitely try this out soon. I use one off python scripts to find the sample offset and the small residual center frequency difference. This simplifies the process significantly. This should make it much easier to implement a passive radar block, or an interferometry block.

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Hi Piotr, Another great stuff from you after Gr-GSM.. thank you for sharing. will take a look there.. best regards, -Bass On Wed, May 25, 2016 at 2:16 AM, Marcus D. Leech wrote: > On 05/24/2016 08:20 PM, Ben Hilburn wrote: > > Hi Piotr - > > Nice work, good docs, and thanks

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

On 05/24/2016 08:20 PM, Ben Hilburn wrote: Hi Piotr - Nice work, good docs, and thanks for sharing this. You should create a proper OOT module from this (you basically already have) and submit the recipe to PyBOMBS and get it on CGRAN! Cheers, Ben Yup, this is good stuff. I will have to

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Hi Piotr - Nice work, good docs, and thanks for sharing this. You should create a proper OOT module from this (you basically already have) and submit the recipe to PyBOMBS and get it on CGRAN! Cheers, Ben On Tue, May 24, 2016 at 4:25 PM, Przemek Lewandowski wrote: >

Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Nice Job :) Good to see friends from Poland playing with GnuRadio :) All Best 2016-05-24 22:03 GMT+02:00 Piotr Krysik : > Hi all, > > I want to announce new GNU Radio related project prepared by me - > Multi-rtl: > https://github.com/ptrkrysik/multi-rtl > > It is a Gnu Radio

[Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

Hi all, I want to announce new GNU Radio related project prepared by me - Multi-rtl: https://github.com/ptrkrysik/multi-rtl It is a Gnu Radio block that combines multiple RTL-SDR receivers into one multi-channel receiver. Only hardware modification to RTL-SDR dongles required is connecting them