From lucas.lorenzi at gmail.com  Thu Aug  1 19:25:15 2013
From: lucas.lorenzi at gmail.com (Lucas Ingles)
Date: Thu, 1 Aug 2013 16:25:15 -0300
Subject: RTL SDR Hardware Architecture
Message-ID: <CAHA_kS3n9Lz89hjmNHtWuPZZ0+=kM7Zi+vK01gmFc7MbRSXUGg@mail.gmail.com>

Hello to all,

I am an electrical engineering student from Brazil and I have already been
studying GNURadio using RTL-SDR for a while (I have an EZCAP dongle). This
is my first post here. I am studying the basic FM receiver and my question
is:

Which is the actual receiver architecture used in the RTL-SDR dongles? I
mean, do we have a Hartley receiver, a Weaver receiver, a zero-IF receiver,
a low-IF receiver?

Also, the E4K tuner has two outputs: one output is the in-phase component
and the other output is the quadrature component. So, does the RTL2832U has
two ADCs to sample the two components? Or just one ADC and it samples the
two components interleaved?

Thanks very much in advance,
Lucas Ingles
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From steve at steve-m.de  Thu Aug  1 20:07:22 2013
From: steve at steve-m.de (Steve Markgraf)
Date: Thu, 01 Aug 2013 22:07:22 +0200
Subject: RTL SDR Hardware Architecture
In-Reply-To: <CAHA_kS3n9Lz89hjmNHtWuPZZ0+=kM7Zi+vK01gmFc7MbRSXUGg@mail.gmail.com>
References: <CAHA_kS3n9Lz89hjmNHtWuPZZ0+=kM7Zi+vK01gmFc7MbRSXUGg@mail.gmail.com>
Message-ID: <51FABFFA.6040406@steve-m.de>

Hi,

On 01.08.2013 21:25, Lucas Ingles wrote:
> Which is the actual receiver architecture used in the RTL-SDR dongles? I
> mean, do we have a Hartley receiver, a Weaver receiver, a zero-IF
> receiver, a low-IF receiver?

Depends on the tuner, the RTL2832 can be used both in zero-IF and in
low-IF mode. For the R820T it's low-IF, for all the other tuners
(including E4K) zero-IF.

> Also, the E4K tuner has two outputs: one output is the in-phase
> component and the other output is the quadrature component. So, does the
> RTL2832U has two ADCs to sample the two components? Or just one ADC and
> it samples the two components interleaved?

It has two ADCs, one for the in-phase and the one for the quadrature
component.

In the low-IF mode only one of them is used, which one can be selected.
The generation of the I/Q signals then is done by an internal DDC.

Regards,
Steve




From lucas.lorenzi at gmail.com  Thu Aug  1 22:16:25 2013
From: lucas.lorenzi at gmail.com (Lucas Ingles)
Date: Thu, 1 Aug 2013 19:16:25 -0300
Subject: RTL SDR Hardware Architecture
In-Reply-To: <51FABFFA.6040406@steve-m.de>
References: <CAHA_kS3n9Lz89hjmNHtWuPZZ0+=kM7Zi+vK01gmFc7MbRSXUGg@mail.gmail.com>
	<51FABFFA.6040406@steve-m.de>
Message-ID: <CAHA_kS2B6mF9=NCndhCoGZRv19cMgSC8qnD3eBV=oaf8awNnBg@mail.gmail.com>

Thank you very much for your response Steve!
This was exactly what I needed.

Regards,
Lucas


2013/8/1 Steve Markgraf <steve at steve-m.de>

> Hi,
>
> On 01.08.2013 21:25, Lucas Ingles wrote:
> > Which is the actual receiver architecture used in the RTL-SDR dongles? I
> > mean, do we have a Hartley receiver, a Weaver receiver, a zero-IF
> > receiver, a low-IF receiver?
>
> Depends on the tuner, the RTL2832 can be used both in zero-IF and in
> low-IF mode. For the R820T it's low-IF, for all the other tuners
> (including E4K) zero-IF.
>
> > Also, the E4K tuner has two outputs: one output is the in-phase
> > component and the other output is the quadrature component. So, does the
> > RTL2832U has two ADCs to sample the two components? Or just one ADC and
> > it samples the two components interleaved?
>
> It has two ADCs, one for the in-phase and the one for the quadrature
> component.
>
> In the low-IF mode only one of them is used, which one can be selected.
> The generation of the I/Q signals then is done by an internal DDC.
>
> Regards,
> Steve
>
>


-- 
Lucas Lorenzi Ingles
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From bwojtowi at gmail.com  Sat Aug  3 23:47:01 2013
From: bwojtowi at gmail.com (Ben Wojtowicz)
Date: Sat, 3 Aug 2013 18:47:01 -0500
Subject: openLTE release V00.08.03
Message-ID: <CAF9-9qkzTOqFsV5kStzVk__6TigFRoYaNAu03mJWQRmqp8Uvqg@mail.gmail.com>

All,

I have released openLTE V00.08.03 (http://sourceforge.net/projects/openlte/)
with support for HackRF and RTL-SDR via GrOsmoSDR.  Using this release, I
have been able to successfully decode broadcast information (MIB and SIBs)
from LTE networks.

I was also wondering if there is a good way to determine which type of
hardware is connected?  Currently I am using the get_sample_rates routine
and comparing the maximum against the expected max for each hardware type.

Thanks,
Ben
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From slothpuck at gmail.com  Sun Aug  4 15:24:09 2013
From: slothpuck at gmail.com (lee jones)
Date: Sun, 4 Aug 2013 16:24:09 +0100
Subject: Problems compiling rtl-sdr on debian
Message-ID: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>

Hello all!

Just been trying to compile rtl-sdr (
http://sdr.osmocom.org/trac/wiki/rtl-sdr ) on my linux box but I'm
having a few problems. Btw the linux distro is debian running a 64-bit
kernel; 3.10-1-amd64.

Here's the problem. I can't seem to get rtl-sdr to compile quite right
either with the cmake or autotools instructions from the sdr website.
I've tried both methods; only one completes (but produces an unstable
version) the other version dosen't compile at all.

Here's the output I get from trying to build by using cmake -
http://slothpuck.no-ip.org/tmp/cmake-build.txt

and then with autotools method -
http://slothpuck.no-ip.org/tmp/autoconf-build.txt

I get a lot of errors with the cmake method with lots of warnings
about unused paramaters; the autotools method dosen't even complete.
The cmake version does however but appears to be very unstable. If I
try to run one of the programs made by rtl-sdr -- the program rtl_tcp
with another program such as gqrx, .e.g by starting rtl_tcp in a
terminal then run gqrx in another (
http://www.oz9aec.net/index.php/gnu-radio/gqrx-sdr ) I find it causes
rtl_tcp to crash - either with a segfault, or with a  "worker cond
timeout, signal caught exiting!" message (rtl_tcp hung in this case).

I do have libusb (both library and dev) and gnuradio installed btw.

any thoughts on what might be going wrong at all? Thanks

ljones



From horiz0n at gmx.net  Sun Aug  4 15:36:34 2013
From: horiz0n at gmx.net (Dimitri Stolnikov)
Date: Sun, 04 Aug 2013 17:36:34 +0200
Subject: openLTE release V00.08.03
In-Reply-To: <CAF9-9qkzTOqFsV5kStzVk__6TigFRoYaNAu03mJWQRmqp8Uvqg@mail.gmail.com>
References: <CAF9-9qkzTOqFsV5kStzVk__6TigFRoYaNAu03mJWQRmqp8Uvqg@mail.gmail.com>
Message-ID: <op.w1atm8guvay7ep@wopr.artelis.net>

Hi Ben,

> I have released openLTE V00.08.03  
> (http://sourceforge.net/projects/openlte/)
> with support for HackRF and RTL-SDR via GrOsmoSDR. Using this release, I
> have been able to successfully decode broadcast information (MIB and  
> SIBs)
> from LTE networks.

Thanks for the update & congratulations!

> I was also wondering if there is a good way to determine which type of
> hardware is connected?

Ideally you enumerate through available devices and select one to work  
with (example attached). Then you pass it's device string to the  
source/sink and continue from there as usual. You can check for something  
like dev.count("rtl") || dev.count("rtl_tcp") and dev.count("hackrf") to  
distinguish between devices. In our applications we also provide a command  
line switch like

         parser.add_option("-a", "--args", type="string", default="",
                           help="Device args, [default=%default]")

to select a specific device via CLI and to be able to change it's default  
parameters: -a "hackrf,buffers=128".


Best regards,
Dimitri
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From df8oe at gmx.de  Sun Aug  4 15:43:55 2013
From: df8oe at gmx.de (df8oe at gmx.de)
Date: Sun, 4 Aug 2013 17:43:55 +0200
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
Message-ID: <201308041743.56095.df8oe@gmx.de>

Am Sonntag, 4. August 2013, 17:24:09 schrieb lee jones:
> Hello all!
> 
> Just been trying to compile rtl-sdr (
> http://sdr.osmocom.org/trac/wiki/rtl-sdr ) on my linux box but I'm
> having a few problems. Btw the linux distro is debian running a 64-bit
> kernel; 3.10-1-amd64.
> 
> Here's the problem. I can't seem to get rtl-sdr to compile quite right
> either with the cmake or autotools instructions from the sdr website.
> I've tried both methods; only one completes (but produces an unstable
> version) the other version dosen't compile at all.

Look at the following line - it is telling you everything you want to know...

Could NOT find PkgConfig (missing:  PKG_CONFIG_EXECUTABLE) 


Good luck
Andreas



From bwojtowi at gmail.com  Sun Aug  4 17:54:56 2013
From: bwojtowi at gmail.com (Ben Wojtowicz)
Date: Sun, 4 Aug 2013 12:54:56 -0500
Subject: openLTE release V00.08.03
In-Reply-To: <op.w1atm8guvay7ep@wopr.artelis.net>
References: <CAF9-9qkzTOqFsV5kStzVk__6TigFRoYaNAu03mJWQRmqp8Uvqg@mail.gmail.com>
	<op.w1atm8guvay7ep@wopr.artelis.net>
Message-ID: <CAF9-9qkU94p=HHeF15m05kW8uWnBB_K9qm+SK0_Yguhg86ML5Q@mail.gmail.com>

Dimitri,

Thanks for the example code!  I'll roll this into the next release.

Thanks,
Ben


On Sun, Aug 4, 2013 at 10:36 AM, Dimitri Stolnikov <horiz0n at gmx.net> wrote:

> Hi Ben,
>
>
>  I have released openLTE V00.08.03 (http://sourceforge.net/**
>> projects/openlte/ <http://sourceforge.net/projects/openlte/>)
>> with support for HackRF and RTL-SDR via GrOsmoSDR. Using this release, I
>> have been able to successfully decode broadcast information (MIB and SIBs)
>> from LTE networks.
>>
>
> Thanks for the update & congratulations!
>
>
>  I was also wondering if there is a good way to determine which type of
>> hardware is connected?
>>
>
> Ideally you enumerate through available devices and select one to work
> with (example attached). Then you pass it's device string to the
> source/sink and continue from there as usual. You can check for something
> like dev.count("rtl") || dev.count("rtl_tcp") and dev.count("hackrf") to
> distinguish between devices. In our applications we also provide a command
> line switch like
>
>         parser.add_option("-a", "--args", type="string", default="",
>                           help="Device args, [default=%default]")
>
> to select a specific device via CLI and to be able to change it's default
> parameters: -a "hackrf,buffers=128".
>
>
> Best regards,
> Dimitri
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From slothpuck at gmail.com  Sun Aug  4 21:07:22 2013
From: slothpuck at gmail.com (lee jones)
Date: Sun, 4 Aug 2013 22:07:22 +0100
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
Message-ID: <CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>

On 8/4/13, lee jones <slothpuck at gmail.com> wrote:
>>Look at the following line - it is telling you everything you want to
>> know...
>>Could NOT find PkgConfig (missing:  PKG_CONFIG_EXECUTABLE)
>
> Will try that though not sure why on the other method the configure
> script wouldn't complete! x.x
>

Ok I gave that a try. I managed to track down the missing pkgconfig file.

The line about not finding pkgconfig has now gone - but all of the
errors at compile time are all still there, and rtl_tcp still crashes.
Installing pkg-config got rid of the error, but not much else
unfortunarly x.x

ljones



From slothpuck at gmail.com  Sun Aug  4 20:54:58 2013
From: slothpuck at gmail.com (lee jones)
Date: Sun, 4 Aug 2013 21:54:58 +0100
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <201308041743.56095.df8oe@gmx.de>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
Message-ID: <CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>

>Look at the following line - it is telling you everything you want to know...
>Could NOT find PkgConfig (missing:  PKG_CONFIG_EXECUTABLE)

Will try that though not sure why on the other method the configure
script wouldn't complete! x.x

ljones

On 8/4/13, df8oe at gmx.de <df8oe at gmx.de> wrote:
> Am Sonntag, 4. August 2013, 17:24:09 schrieb lee jones:
>> Hello all!
>>
>> Just been trying to compile rtl-sdr (
>> http://sdr.osmocom.org/trac/wiki/rtl-sdr ) on my linux box but I'm
>> having a few problems. Btw the linux distro is debian running a 64-bit
>> kernel; 3.10-1-amd64.
>>
>> Here's the problem. I can't seem to get rtl-sdr to compile quite right
>> either with the cmake or autotools instructions from the sdr website.
>> I've tried both methods; only one completes (but produces an unstable
>> version) the other version dosen't compile at all.
>
> Look at the following line - it is telling you everything you want to
> know...
>
> Could NOT find PkgConfig (missing:  PKG_CONFIG_EXECUTABLE)
>
>
> Good luck
> Andreas
>
>


-- 
:)

SP



From slothpuck at gmail.com  Sun Aug  4 21:43:08 2013
From: slothpuck at gmail.com (lee jones)
Date: Sun, 4 Aug 2013 22:43:08 +0100
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
	<CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
Message-ID: <CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>

I also have re-tried with installing the pkgconfig file recompiling by
using autoconf rather than cmake. But I still get lots of errors;

http://slothpuck.no-ip.org/tmp/autoconf-build2.txt

what's concerning me are all those "unused parameter" error messages,
as if they aren't being built in and that's maybe why rtl_tcp just
hangs or crashes.

ljones

On 8/4/13, lee jones <slothpuck at gmail.com> wrote:
> On 8/4/13, lee jones <slothpuck at gmail.com> wrote:
>>>Look at the following line - it is telling you everything you want to
>>> know...
>>>Could NOT find PkgConfig (missing:  PKG_CONFIG_EXECUTABLE)
>>
>> Will try that though not sure why on the other method the configure
>> script wouldn't complete! x.x
>>
>
> Ok I gave that a try. I managed to track down the missing pkgconfig file.
>
> The line about not finding pkgconfig has now gone - but all of the
> errors at compile time are all still there, and rtl_tcp still crashes.
> Installing pkg-config got rid of the error, but not much else
> unfortunarly x.x
>
> ljones
>


-- 
:)

SP



From slothpuck at gmail.com  Sun Aug  4 22:01:19 2013
From: slothpuck at gmail.com (lee jones)
Date: Sun, 4 Aug 2013 23:01:19 +0100
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
	<CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
	<CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
Message-ID: <CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>

Apologies for continually replying but I also just noticed these
three lines in dmesg as I've been trying all of this out:

[   66.714466] rtl_tcp[3670]: segfault at 0 ip 00007f5d329389f2 sp
00007fff71c8e780 error 6 in libusb-1.0.so.0.1.0[7f5d32930000+15000]
[   87.168292] rtl_tcp[3812]: segfault at 0 ip 00007f0d2fc609f2 sp
00007f0d2e26cb50 error 6 in libusb-1.0.so.0.1.0[7f0d2fc58000+15000]
[  398.814077] rtl_tcp[8760]: segfault at 0 ip 00007f623a1a09f2 sp
00007f62384acb40 error 6 in libusb-1.0.so.0.1.0[7f623a198000+15000]

Maybe this is a case of something not liking libusb at all? BTW here's
some info on the version of libusb I have installed on my system:

# aptitude show libusb-1.0-0
Package: libusb-1.0-0
State: installed
Automatically installed: no
Multi-Arch: same
Version: 2:1.0.16-3
Priority: optional
Section: libs

ljones


On 8/4/13, lee jones <slothpuck at gmail.com> wrote:
> I also have re-tried with installing the pkgconfig file recompiling by
> using autoconf rather than cmake. But I still get lots of errors;
>
> http://slothpuck.no-ip.org/tmp/autoconf-build2.txt
>
> what's concerning me are all those "unused parameter" error messages,
> as if they aren't being built in and that's maybe why rtl_tcp just
> hangs or crashes.
>
> ljones
>
> On 8/4/13, lee jones <slothpuck at gmail.com> wrote:
>> On 8/4/13, lee jones <slothpuck at gmail.com> wrote:
>>>>Look at the following line - it is telling you everything you want to
>>>> know...
>>>>Could NOT find PkgConfig (missing:  PKG_CONFIG_EXECUTABLE)
>>>
>>> Will try that though not sure why on the other method the configure
>>> script wouldn't complete! x.x
>>>
>>
>> Ok I gave that a try. I managed to track down the missing pkgconfig file.
>>
>> The line about not finding pkgconfig has now gone - but all of the
>> errors at compile time are all still there, and rtl_tcp still crashes.
>> Installing pkg-config got rid of the error, but not much else
>> unfortunarly x.x
>>
>> ljones
>>
>
>
> --
> :)
>
> SP
>


-- 
:)

SP



From df8oe at gmx.de  Mon Aug  5 05:59:37 2013
From: df8oe at gmx.de (df8oe at gmx.de)
Date: Mon, 5 Aug 2013 07:59:37 +0200
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
	<CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
Message-ID: <201308050759.38037.df8oe@gmx.de>

Am Montag, 5. August 2013, 00:01:19 schrieb lee jones:
> Apologies for continually replying but I also just noticed these
> three lines in dmesg as I've been trying all of this out:
> 
> [   66.714466] rtl_tcp[3670]: segfault at 0 ip 00007f5d329389f2 sp
> 00007fff71c8e780 error 6 in libusb-1.0.so.0.1.0[7f5d32930000+15000]
> [   87.168292] rtl_tcp[3812]: segfault at 0 ip 00007f0d2fc609f2 sp
> 00007f0d2e26cb50 error 6 in libusb-1.0.so.0.1.0[7f0d2fc58000+15000]
> [  398.814077] rtl_tcp[8760]: segfault at 0 ip 00007f623a1a09f2 sp
> 00007f62384acb40 error 6 in libusb-1.0.so.0.1.0[7f623a198000+15000]
> 
> Maybe this is a case of something not liking libusb at all? BTW here's
> some info on the version of libusb I have installed on my system:
> 
> # aptitude show libusb-1.0-0
> Package: libusb-1.0-0
> State: installed
> Automatically installed: no
> Multi-Arch: same
> Version: 2:1.0.16-3
> Priority: optional
> Section: libs
> 


You have missing packages at all - I think *dev-packages.

Do you have run 'make clean' before trying to build again? This can reduce error.messages to 
the ones you need for lacating the problem...

Here you can find a small howto on compiling rtlsdr:

 http://pd0mz.nl/2012/04/13/rtl2832u-chipset-makes-a-cheap-software-defined-radio-part-2/

Good luck
Andreas



From peter at stuge.se  Mon Aug  5 11:18:41 2013
From: peter at stuge.se (Peter Stuge)
Date: Mon, 5 Aug 2013 13:18:41 +0200
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
	<CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
	<CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
	<CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
Message-ID: <20130805111841.11860.qmail@stuge.se>

lee jones wrote:
> [   66.714466] rtl_tcp[3670]: segfault at 0 ip 00007f5d329389f2 sp
> 00007fff71c8e780 error 6 in libusb-1.0.so.0.1.0[7f5d32930000+15000]
> [   87.168292] rtl_tcp[3812]: segfault at 0 ip 00007f0d2fc609f2 sp
> 00007f0d2e26cb50 error 6 in libusb-1.0.so.0.1.0[7f0d2fc58000+15000]
> [  398.814077] rtl_tcp[8760]: segfault at 0 ip 00007f623a1a09f2 sp
> 00007f62384acb40 error 6 in libusb-1.0.so.0.1.0[7f623a198000+15000]

This shows a crash inside the library. That is caused either by a bug
in the library or by a bug in the application.


> Maybe this is a case of something not liking libusb at all? BTW here's
> some info on the version of libusb I have installed on my system:
> 
> # aptitude show libusb-1.0-0
> Package: libusb-1.0-0
> State: installed
> Automatically installed: no
> Multi-Arch: same
> Version: 2:1.0.16-3
> Priority: optional
> Section: libs

Actually this is not libusb at all. You have libusbx installed, it
was changed to be the default in debian and several other
distributions immediately after a Red Hat employee changed
the default in Fedora and wrote a one-line blog post about it.

The libusbx community doesn't value code quality highly so it's
about equally likely that the problem is in libusbx as that it is in
the application calling libusbx.

It would be interesting to see the output from a run that uses
libusb-1.0.9 or better yet the code from libusb.git, but that
requires building it from source and running with the special-built
library. You could look at https://libusb.org/wiki/debug for
copypaste instructions.


//Peter



From slothpuck at gmail.com  Mon Aug  5 17:40:18 2013
From: slothpuck at gmail.com (lee jones)
Date: Mon, 5 Aug 2013 18:40:18 +0100
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <20130805111841.11860.qmail@stuge.se>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
	<CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
	<CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
	<CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
	<20130805111841.11860.qmail@stuge.se>
Message-ID: <CAKwpmoKj4a6Z7t+t5i=E20Jx7FF9Wtdq9Y_SxP2TpLdJKxgFyA@mail.gmail.com>

>It would be interesting to see the output from a run that uses
>libusb-1.0.9 or better yet the code from libusb.git

Should I apt-get remove the libusb (libusbx) before I try this or
leave it installed?

>Hi, Which version of Debian are you using?
I'm using debian 7 but upgraded. Looking at /etc/debian_version it
reports "jessie/sid".

ljones

On 8/5/13, Peter Stuge <peter at stuge.se> wrote:
> lee jones wrote:
>> [   66.714466] rtl_tcp[3670]: segfault at 0 ip 00007f5d329389f2 sp
>> 00007fff71c8e780 error 6 in libusb-1.0.so.0.1.0[7f5d32930000+15000]
>> [   87.168292] rtl_tcp[3812]: segfault at 0 ip 00007f0d2fc609f2 sp
>> 00007f0d2e26cb50 error 6 in libusb-1.0.so.0.1.0[7f0d2fc58000+15000]
>> [  398.814077] rtl_tcp[8760]: segfault at 0 ip 00007f623a1a09f2 sp
>> 00007f62384acb40 error 6 in libusb-1.0.so.0.1.0[7f623a198000+15000]
>
> This shows a crash inside the library. That is caused either by a bug
> in the library or by a bug in the application.
>
>
>> Maybe this is a case of something not liking libusb at all? BTW here's
>> some info on the version of libusb I have installed on my system:
>>
>> # aptitude show libusb-1.0-0
>> Package: libusb-1.0-0
>> State: installed
>> Automatically installed: no
>> Multi-Arch: same
>> Version: 2:1.0.16-3
>> Priority: optional
>> Section: libs
>
> Actually this is not libusb at all. You have libusbx installed, it
> was changed to be the default in debian and several other
> distributions immediately after a Red Hat employee changed
> the default in Fedora and wrote a one-line blog post about it.
>
> The libusbx community doesn't value code quality highly so it's
> about equally likely that the problem is in libusbx as that it is in
> the application calling libusbx.
>
> It would be interesting to see the output from a run that uses
> libusb-1.0.9 or better yet the code from libusb.git, but that
> requires building it from source and running with the special-built
> library. You could look at https://libusb.org/wiki/debug for
> copypaste instructions.
>
>
> //Peter
>
>


-- 
:)

SP



From wk at ire.pw.edu.pl  Mon Aug  5 23:14:44 2013
From: wk at ire.pw.edu.pl (wk at ire.pw.edu.pl)
Date: Tue, 06 Aug 2013 01:14:44 +0200
Subject: gr-iqbalance documentation build problem
Message-ID: <sig.2929a0791f.20130806011444.600yhyvj9cwow44k@www.ire.pw.edu.pl>

Hello.
I have some build problem with building gr-igbalance with documentation
enabled. Build fails with a message saying that shell interpreter can't
execute Doxyfile. It is the same as I noticed some time ago while
building gr-osmosdr (see
http://lists.osmocom.org/pipermail/osmocom-sdr/2013-April/000553.html
). It was solved by the patch by Jaroslav ?karvada (
http://cgit.osmocom.org/gr-osmosdr/commit/?id=2f6592566bd60d2539f5b976dcf6119876a0e0
).

Similar patch, attached, help for gr-iqbalance. It moves doxygen
detection test to toplevel CMakeLists.txt. Please add it to git
repository.

Wojciech Kazubski


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From r.ranson at ieee.org  Wed Aug  7 09:49:16 2013
From: r.ranson at ieee.org (Richard Ranson)
Date: Wed, 7 Aug 2013 10:49:16 +0100
Subject: IQ Balance
Message-ID: <CAMJiz+gdyh==MtBEO9rLB3yOtXwGTYpDX_fb2PZ+5MejozMpgA@mail.gmail.com>

I am new to this group and would appreciate any help.

Looking at the rtlsdr driver, I see that there seems to be some code to
correct the IQ balance, but I'm only going by the names of functions like
"_IQ_Tree" and "_Compare_Cor".  The algorithm, if there is one, is not at
all clear nor of direct interest, the question is whether or not there is
some IQ balance built into the rtlsdr driver and does anyone know how
effective (e.g. in terms of image suppression) it is.

Then, I'm using this device and software to demonstrate to students the
concepts of SDR. So on a related note, if there is some IQ balance
correction in the driver, can it be turned off? Changing the driver code is
way beyond my ability, but some digging suggests that changing the header
file to have
#define IMR_TRIAL 0.
eliminates a quite complex looking loop of computation that may be the IQ
balance scheme. As a newbie I wouldn't attempt this without some positive
guidance.

It would require a new build of the driver, which I imagine is the same as
for the normal case, and then if it can be done, it would be great to
illustrate the basic IQ balance of the hardware and the improvement
possible with software correction.

thanks Richard
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From steve at steve-m.de  Wed Aug  7 17:23:57 2013
From: steve at steve-m.de (Steve Markgraf)
Date: Wed, 07 Aug 2013 19:23:57 +0200
Subject: IQ Balance
In-Reply-To: <CAMJiz+gdyh==MtBEO9rLB3yOtXwGTYpDX_fb2PZ+5MejozMpgA@mail.gmail.com>
References: <CAMJiz+gdyh==MtBEO9rLB3yOtXwGTYpDX_fb2PZ+5MejozMpgA@mail.gmail.com>
Message-ID: <520282AD.4010307@steve-m.de>

Hi,

On 07.08.2013 11:49, Richard Ranson wrote:
> Looking at the rtlsdr driver, I see that there seems to be some code to
> correct the IQ balance, but I'm only going by the names of functions
> like "_IQ_Tree" and "_Compare_Cor".  The algorithm, if there is one, is
> not at all clear nor of direct interest, the question is whether or not
> there is some IQ balance built into the rtlsdr driver and does anyone
> know how effective (e.g. in terms of image suppression) it is.

What you're looking at is dead code in the r820t tuner driver (which
presumably can correct the internal IQ-offset, as this is a low-IF
tuner). But we're not using it right now, thus it is never called.

For all the other tuners (which are zero-IF) we enable the internal IQ-
compensation of the RTL2832, see [1].
However, it is not really documented and understood what that does, the
observed effects are minimal.

If you want to see for yourself you can disable the internal
compensation, change that write to:
rtlsdr_demod_write_reg(dev, 1, 0xb1, 0x03, 1);

For software IQ-compensation we have the gr-iqbal GNU Radio block:
http://cgit.osmocom.org/gr-iqbal/

Regards,
Steve

[1] http://cgit.osmocom.org/rtl-sdr/tree/src/librtlsdr.c#n562



From soliton33 at live.com  Thu Aug  8 04:13:33 2013
From: soliton33 at live.com (Neela Neela)
Date: Thu, 8 Aug 2013 00:13:33 -0400
Subject: Filtering in baseband spectrum
Message-ID: <BLU162-W1892AA0330E8BD3F630B54CF5F0@phx.gbl>

Hi
 I am a beginner with RTL and observing that the baseband spectrum is centred at 0 Hz and is asymmetric going from -1 MHz to +1 MHz. How does one filter a part of such a spectrum? For example if signal of interest lied in -300 kHz to -150 kHz.   The filtering techniques for typical band pass filters work with positive frequencies and have symmetric frequency selection response. As such a 150 to 300 KHz band pass filter will select signal in both 150 to 300 kHz band as well as from -150 to 300 kHz. Is there a special filtering method available to work with negative frequencies and with an asymmetric baseband spectrum.  I am sure this has been addressed as preassumably the FM and other signals of interest are filtered somehow. Any indications will be appreciated.  Regards  		 	   		  
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From leif at sm5bsz.com  Thu Aug  8 22:16:57 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Fri, 9 Aug 2013 00:16:57 +0200
Subject: Filtering in baseband spectrum
In-Reply-To: <BLU162-W1892AA0330E8BD3F630B54CF5F0@phx.gbl>
References: <BLU162-W1892AA0330E8BD3F630B54CF5F0@phx.gbl>
Message-ID: <20130809001657.f54cf529369229c1e6d0675a@sm5bsz.com>

He Neela,

I think the most efficienmt solution is to first shift the frequency.
The average of -300 and -150 kHz is -225 kHz so you need to multiply
the samples by the appropriater sine and cosine functions.

After that your signal will be centered at 0Hz and it will extend
to +/- 75 kHz. Now you can apply low pass filters with a bandwidth of
75 kHz. Probably it would be clever to resample in the same procedure.

For 150 kHz bandwidth you would not need much above 150 kHz sampling
rate. The rtl should run at the highest possible rate because the
dynamic range improves when sampling is faster.

Regards

Leif



>  I am a beginner with RTL and observing that the baseband spectrum is centred at 0 Hz and is asymmetric going from -1 MHz to +1 MHz. How does one filter a part of such a spectrum? For example if signal of interest lied in -300 kHz to -150 kHz.   The filtering techniques for typical band pass filters work with positive frequencies and have symmetric frequency selection response. As such a 150 to 300 KHz band pass filter will select signal in both 150 to 300 kHz band as well as from -150 to 300 kHz. Is there a special filtering method available to work with negative frequencies and with an asymmetric baseband spectrum.  I am sure this has been addressed as preassumably the FM and other signals of interest are filtered somehow. Any indications will be appreciated.  Regards  		 	   		  



From capeorion at gmail.com  Fri Aug  9 12:03:31 2013
From: capeorion at gmail.com (Andrew Mount)
Date: Fri, 9 Aug 2013 08:03:31 -0400
Subject: Need a starting point to learn RTL-SDR
Message-ID: <CABDbH9und4yKJzbCX55bX57rcKaoCPw+YexX06hzftd-UUHfFw@mail.gmail.com>

Are there any good books or Internet references that the listserv members
could recommend as a starting point ?

I am an amateur astronomer who is interested in learning how to use RTL-SDR
to do radio astronomy.

Thank you,

Andy Mount
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From andrew at carrierdetect.com  Fri Aug  9 12:37:42 2013
From: andrew at carrierdetect.com (Andrew Back)
Date: Fri, 9 Aug 2013 13:37:42 +0100
Subject: Need a starting point to learn RTL-SDR
In-Reply-To: <CABDbH9und4yKJzbCX55bX57rcKaoCPw+YexX06hzftd-UUHfFw@mail.gmail.com>
References: <CABDbH9und4yKJzbCX55bX57rcKaoCPw+YexX06hzftd-UUHfFw@mail.gmail.com>
Message-ID: <CADj1OPA5Ekkp0-EMhsVUwOnhaU3dsAuFPApn0hUkEMKP7zNKVA@mail.gmail.com>

On 9 August 2013 13:03, Andrew Mount <capeorion at gmail.com> wrote:
> Are there any good books or Internet references that the listserv members
> could recommend as a starting point ?
>
> I am an amateur astronomer who is interested in learning how to use RTL-SDR
> to do radio astronomy.

The top Google result looks promising:

  http://www.rtl-sdr.com/rtl-sdr-for-budget-radio-astronomy/

Regards,

Andrew

-- 
Andrew Back
http://carrierdetect.com



From capeorion at gmail.com  Fri Aug  9 14:24:41 2013
From: capeorion at gmail.com (Andrew Mount)
Date: Fri, 9 Aug 2013 10:24:41 -0400
Subject: Fwd: Need a starting point to learn RTL-SDR
In-Reply-To: <CABDbH9sSen84dMwCntBKVmYs3NfNGauf1Roo=MAM4T2bn0dpKw@mail.gmail.com>
References: <CABDbH9und4yKJzbCX55bX57rcKaoCPw+YexX06hzftd-UUHfFw@mail.gmail.com>
	<CADj1OPA5Ekkp0-EMhsVUwOnhaU3dsAuFPApn0hUkEMKP7zNKVA@mail.gmail.com>
	<CABDbH9sSen84dMwCntBKVmYs3NfNGauf1Roo=MAM4T2bn0dpKw@mail.gmail.com>
Message-ID: <CABDbH9sy_W=jsnhi9ehmrJTTEHJOHZE9Hhr4PDFRG1TjZ5pGHw@mail.gmail.com>

---------- Forwarded message ----------
From: *Andrew Mount*
Date: Friday, August 9, 2013
Subject: Need a starting point to learn RTL-SDR
To: Andrew Back <andrew at carrierdetect.com>, "
osmocom-sdr-request at lists.osmocom.org" <
osmocom-sdr-request at lists.osmocom.org>


Andrew,

Thank you.

I have two radio astronomy projects in mind. The first is a HF system that
will enable  me to pick or zoom into a narrow band of frequencies  , say
20-22 mHZ from a larger 18 - 26 mHZ  range ( currently scanned by a
spectrograph) to study N type storm events from Jupiter.   This will
require coding on my part as I have to interface with pre-existing software
in order to load data accepted by the  NASA RADIO JOVE archive.

The other application ( much easier) is to build an RTL based  220 mHZ
range meteor scatter detection system.  The meteor detection system is the
current project.  I have the computer, the RTL and am waiting on the
antenna, ( due to arrive  by 30 August).  This has already been worked out
software wise,  it is a plug and chug type of project.   The advantage is
that I can be collecting meteor data by the end of the year and I will
learn about RTL SDR in the process.

 In order to build my own custom SDR system, what is needed is knowledge of
a more how to -and what is- type. I need  to learn the technical language,
what programs to use, how an RTL works, integration with a build ( i have
access to Matlab? )  environment,  how to write drivers, etc.  I need  to
know how it works,  how to speak the language and what are the prerequisite
tools to get the job done.

Any suggestions that would build proficiency in these areas would be
invaluable for me.

Thanks for responding so quickly and best wishes,

Andy

On Friday, August 9, 2013, Andrew Back wrote:

> On 9 August 2013 13:03, Andrew Mount <capeorion at gmail.com> wrote:
> > Are there any good books or Internet references that the listserv members
> > could recommend as a starting point ?
> >
> > I am an amateur astronomer who is interested in learning how to use
> RTL-SDR
> > to do radio astronomy.
>
> The top Google result looks promising:
>
>   http://www.rtl-sdr.com/rtl-sdr-for-budget-radio-astronomy/
>
> Regards,
>
> Andrew
>
> --
> Andrew Back
> http://carrierdetect.com
>
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From jsalsburg at bellsouth.net  Sun Aug 11 00:24:26 2013
From: jsalsburg at bellsouth.net (Jay Salsburg)
Date: Sat, 10 Aug 2013 19:24:26 -0500
Subject: Need a starting point to learn RTL-SDR
In-Reply-To: <CABDbH9sy_W=jsnhi9ehmrJTTEHJOHZE9Hhr4PDFRG1TjZ5pGHw@mail.gmail.com>
References: <CABDbH9und4yKJzbCX55bX57rcKaoCPw+YexX06hzftd-UUHfFw@mail.gmail.com>	<CADj1OPA5Ekkp0-EMhsVUwOnhaU3dsAuFPApn0hUkEMKP7zNKVA@mail.gmail.com>	<CABDbH9sSen84dMwCntBKVmYs3NfNGauf1Roo=MAM4T2bn0dpKw@mail.gmail.com>
	<CABDbH9sy_W=jsnhi9ehmrJTTEHJOHZE9Hhr4PDFRG1TjZ5pGHw@mail.gmail.com>
Message-ID: <!&!AAAAAAAAAAAYAAAAAAAAALO4+13dC3JEngpmoHTALLLCgAAAEAAAAI9OSbhFLbVFkGxG0dMpscUBAAAAAA==@bellsouth.net>

As far as I understand, you do not need to write drivers or custom software,
but you may be doing something not understood in your message. Radio
Astronomy at 18-22 MHz is possible but not with any of those low cost
Dongles, for 2 general reasons. The biggest is that there are none available
for those frequencies; 18-22 MHz, the other is that they are noisy, with
only 8bit conversion. Use the SoftRock for Astronomy (Antennas are more
important). http://fivedash.com/

 

Radio Astronomy requires narrow band, high dynamic range, and high bit depth
all of which these dongle do not provide. The same restrictions apply for
the NAVSPASUR reception. After you build a very good antenna, NAVSPASUR
monitoring for meteors requires a CW, 3k bandwidth, with moderately good
frequency stability.

 

Visit my web site for massive content.

http://www.salsburg.com/NAVSPASUR/

 

 

From: osmocom-sdr-bounces at lists.osmocom.org
[mailto:osmocom-sdr-bounces at lists.osmocom.org] On Behalf Of Andrew Mount
Sent: Friday, August 09, 2013 9:25 AM
To: osmocom-sdr at lists.osmocom.org
Subject: Fwd: Need a starting point to learn RTL-SDR

 



---------- Forwarded message ----------
From: Andrew Mount 
Date: Friday, August 9, 2013
Subject: Need a starting point to learn RTL-SDR
To: Andrew Back <andrew at carrierdetect.com>,
"osmocom-sdr-request at lists.osmocom.org"
<osmocom-sdr-request at lists.osmocom.org>


Andrew,

 

Thank you.   

 

I have two radio astronomy projects in mind. The first is a HF system that
will enable  me to pick or zoom into a narrow band of frequencies  , say
20-22 mHZ from a larger 18 - 26 mHZ  range ( currently scanned by a
spectrograph) to study N type storm events from Jupiter.   This will require
coding on my part as I have to interface with pre-existing software in order
to load data accepted by the  NASA RADIO JOVE archive.

 

The other application ( much easier) is to build an RTL based  220 mHZ range
meteor scatter detection system.  The meteor detection system is the current
project.  I have the computer, the RTL and am waiting on the antenna, ( due
to arrive  by 30 August).  This has already been worked out software wise,
it is a plug and chug type of project.   The advantage is that I can be
collecting meteor data by the end of the year and I will learn about RTL SDR
in the process. 

 

 In order to build my own custom SDR system, what is needed is knowledge of
a more how to -and what is- type. I need  to learn the technical language,
what programs to use, how an RTL works, integration with a build ( i have
access to Matlab? )  environment,  how to write drivers, etc.  I need  to
know how it works,  how to speak the language and what are the prerequisite
tools to get the job done. 

 

Any suggestions that would build proficiency in these areas would be
invaluable for me. 

 

Thanks for responding so quickly and best wishes,

 

Andy 


On Friday, August 9, 2013, Andrew Back wrote:

On 9 August 2013 13:03, Andrew Mount <capeorion at gmail.com> wrote:
> Are there any good books or Internet references that the listserv members
> could recommend as a starting point ?
>
> I am an amateur astronomer who is interested in learning how to use
RTL-SDR
> to do radio astronomy.

The top Google result looks promising:

  http://www.rtl-sdr.com/rtl-sdr-for-budget-radio-astronomy/

Regards,

Andrew

--
Andrew Back
http://carrierdetect.com

 

  _____  

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.2904 / Virus Database: 3211/6568 - Release Date: 08/10/13

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From capeorion at gmail.com  Sun Aug 11 17:19:37 2013
From: capeorion at gmail.com (Andy Mount)
Date: Sun, 11 Aug 2013 13:19:37 -0400
Subject: Need a starting point to learn RTL-SDR
In-Reply-To: <!&!AAAAAAAAAAAYAAAAAAAAALO4+13dC3JEngpmoHTALLLCgAAAEAAAAI9OSbhFLbVFkGxG0dMpscUBAAAAAA==@bellsouth.net>
References: <CABDbH9und4yKJzbCX55bX57rcKaoCPw+YexX06hzftd-UUHfFw@mail.gmail.com>
	<CADj1OPA5Ekkp0-EMhsVUwOnhaU3dsAuFPApn0hUkEMKP7zNKVA@mail.gmail.com>
	<CABDbH9sSen84dMwCntBKVmYs3NfNGauf1Roo=MAM4T2bn0dpKw@mail.gmail.com>
	<CABDbH9sy_W=jsnhi9ehmrJTTEHJOHZE9Hhr4PDFRG1TjZ5pGHw@mail.gmail.com>
	<!&!AAAAAAAAAAAYAAAAAAAAALO4+13dC3JEngpmoHTALLLCgAAAEAAAAI9OSbhFLbVFkGxG0dMpscUBAAAAAA==@bellsouth.net>
Message-ID: <AC693BFA-8274-401B-B61D-5A07AEDC7FD1@gmail.com>

Jay,

Thank you!  Which Softrock receiver do you recommend for NAVSPASUR ? 

Best wishes,

Andy 

Sent from my iPad

On Aug 10, 2013, at 8:24 PM, "Jay Salsburg" <jsalsburg at bellsouth.net> wrote:

> As far as I understand, you do not need to write drivers or custom software, but you may be doing something not understood in your message. Radio Astronomy at 18-22 MHz is possible but not with any of those low cost Dongles, for 2 general reasons. The biggest is that there are none available for those frequencies; 18-22 MHz, the other is that they are noisy, with only 8bit conversion. Use the SoftRock for Astronomy (Antennas are more important). http://fivedash.com/
>  
> Radio Astronomy requires narrow band, high dynamic range, and high bit depth all of which these dongle do not provide. The same restrictions apply for the NAVSPASUR reception. After you build a very good antenna, NAVSPASUR monitoring for meteors requires a CW, 3k bandwidth, with moderately good frequency stability.
>  
> Visit my web site for massive content.
> http://www.salsburg.com/NAVSPASUR/
>  
>  
> From: osmocom-sdr-bounces at lists.osmocom.org [mailto:osmocom-sdr-bounces at lists.osmocom.org] On Behalf Of Andrew Mount
> Sent: Friday, August 09, 2013 9:25 AM
> To: osmocom-sdr at lists.osmocom.org
> Subject: Fwd: Need a starting point to learn RTL-SDR
>  
> 
> 
> ---------- Forwarded message ----------
> From: Andrew Mount 
> Date: Friday, August 9, 2013
> Subject: Need a starting point to learn RTL-SDR
> To: Andrew Back <andrew at carrierdetect.com>, "osmocom-sdr-request at lists.osmocom.org" <osmocom-sdr-request at lists.osmocom.org>
> 
> 
> Andrew,
>  
> Thank you.   
>  
> I have two radio astronomy projects in mind. The first is a HF system that will enable  me to pick or zoom into a narrow band of frequencies  , say 20-22 mHZ from a larger 18 - 26 mHZ  range ( currently scanned by a spectrograph) to study N type storm events from Jupiter.   This will require coding on my part as I have to interface with pre-existing software in order to load data accepted by the  NASA RADIO JOVE archive.
>  
> The other application ( much easier) is to build an RTL based  220 mHZ range meteor scatter detection system.  The meteor detection system is the current project.  I have the computer, the RTL and am waiting on the antenna, ( due to arrive  by 30 August).  This has already been worked out software wise,  it is a plug and chug type of project.   The advantage is that I can be collecting meteor data by the end of the year and I will learn about RTL SDR in the process. 
>  
>  In order to build my own custom SDR system, what is needed is knowledge of a more how to -and what is- type. I need  to learn the technical language, what programs to use, how an RTL works, integration with a build ( i have access to Matlab? )  environment,  how to write drivers, etc.  I need  to know how it works,  how to speak the language and what are the prerequisite tools to get the job done. 
>  
> Any suggestions that would build proficiency in these areas would be invaluable for me. 
>  
> Thanks for responding so quickly and best wishes,
>  
> Andy 
> 
> On Friday, August 9, 2013, Andrew Back wrote:
> On 9 August 2013 13:03, Andrew Mount <capeorion at gmail.com> wrote:
> > Are there any good books or Internet references that the listserv members
> > could recommend as a starting point ?
> >
> > I am an amateur astronomer who is interested in learning how to use RTL-SDR
> > to do radio astronomy.
> 
> The top Google result looks promising:
> 
>   http://www.rtl-sdr.com/rtl-sdr-for-budget-radio-astronomy/
> 
> Regards,
> 
> Andrew
> 
> --
> Andrew Back
> http://carrierdetect.com
>  
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2013.0.2904 / Virus Database: 3211/6568 - Release Date: 08/10/13
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From leif at sm5bsz.com  Sun Aug 11 20:48:51 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Sun, 11 Aug 2013 22:48:51 +0200
Subject: About 'internal AGC'
In-Reply-To: <003501ce9663$0d096010$271c2030$@me.uk>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
Message-ID: <20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>

Hi Charlie,

The controls for AGC do not affect the peculiar wideband LNA AGC
in the R820T chip. The RTL1090 uses the same rtlsdr.dll as is
used by SDR#. I do not know how to evaluate noise levels and signal
levels in RTL1090, but with SDR# one can see funny things
directly on the waterfall.

The LNA is followed by a VERY sensitive power detector that
is somehow followed by filters and amplifiers. It is arranged
in a way to not react on narrowband signals, but already a 3 dB
increase of the noise floor causes a loss of gain through AGC
action.

Most striking is this experiment:

Connect a combiner to the input of the dongle and use it to 
combine a signal generator and a noise source. The noise
source needs a filter that assures that it does not add any noise
on the frequency of the desired signal. It is OK to use a 
T-connector if you do not have a wideband combiner.

I used a 100 MHz low pass filter connected to a vacuum diode
noise source cabable of delivering 17 dB excess noise combined
with a signal generator on 144 MHz by use of a T connector.

I used SDR# to look at the spectrum around 144 MHz.

Without "RTL AGC" and without "Tuner AGC" the noise floor does not
change when the noise source is switched on or off. That is expected
because the noise source can not send any noise through the 100 MHz
low pass filter. That is true at modest gain settings, but if
the gain is set at maximum (49.6 dB) the noise floor increases by 3 dB 
when the noise source is turned on. A small but unexpected effect.

The signal however is attenuated by 23 dB for a total loss at max
gain of S/N of 26 dB!!!!! Please note that the true S/N is not affected 
at all. There is no noise added at 144 MHz.

If I switch on "RTL AGC" or "Tuner AGC" or both, S/N still changes 
the same way. Depending on the signal level of the 144 MHz signal
one can see the signal go down or the noise go up. Or both.

The way sensitivity is lost due to out-of-band noise is invisible 
to the user. There is no warning about overload.

The noise power from 0 to 100 MHz is -174+17+80 = -77 dBm
( -174 dBm/Hz = room temp)
( +17 dB is excess noise)
( +80dB is 100/MHz/1Hz)
There is some filter loss and the dongle presumably has a high pass
filter so one can assume that the noise power is -80 dBm RMS.

I have tried to activate the LNA AGC by use of narrowband 
signals in the 50 to 100 MHz range. Even two signals at
-30 dBm each do not have any effect regardless of the frequency
spacing. It seems the "intelligent" power detector of the LNA
AGC can reject narrowband signals even if they are much
stronger than the noise floor.

The wideband LNA AGC in the R820T may cause problems when
an up-converter is used in front of the dongle. The noise floor
of the up-converted HF spectrum may cause unexpected loss of
sensitivity in the upper part of the HF spectrum where the
noise floor is low.

Adding a filter for the desired HF band. With some gain to
ensure that the noise floor is higher in the desired frequency 
range than elsewhere could perhaps make the R820T dongles
behave much better.

73

Leif  /  SM5BSZ





 
> I use a R820T chipped dongle for receiving aircraft transponder signals
> through a specialised application called RTL1090 from jetvision, the control
> panel of which allows the tuner and device AGCs to be independently toggled
> on or off. I have not however used this with SDR-Radio in the past so cannot
> comment on the optimum settings.
> 
>  
> 
> 73
> 
> Charlie
> 
> www.G4EST.me.uk
> 
>  
> 
> From: sdr-radio-com at yahoogroups.com [mailto:sdr-radio-com at yahoogroups.com]
> On Behalf Of Leif Asbrink
> Sent: 10 August 2013 22:30
> To: sdr-radio-com at yahoogroups.com
> Subject: [sdr-radio-com] Re: About 'internal AGC'
> 
>  
> 
>   
> 
> Hello Patrick and All,
> 
> The R820T chip has an advanced AGC function that I do not 
> think can be disabled. The chip detects the noise floor 
> in a wide bandwidth and adjusts the gain to keep the noise floor
> constant.
> 
> The wideband AGC has surprising effects. If one tries to measure
> the noise figure with a noise source that is manually switched 
> on and off one finds a really bad NF. That result is false however,
> if one measures S/N of a weak signal one finds the true NF which 
> is quite good.
> 
> To verify the finding one can inject a weak signal together
> with the signal from a noise source. What happens when the
> noise is turned on is that the signal becomes weaker while
> the noise floor does not change.
> 
> A 500 kHz wide filter in front of the R820T chip converts the
> noise from the noise source to a narrowband signal which will
> not affect the wideband AGC.
> 
> I made some effort to switch this feature off but failed.
> 
> The behaviour is probably quite clever for reception of digital TV
> but I find it very disturbing in a general purpose SDR. I did not
> take notes and I did not investigate in detail what types of signals
> will affect the AGC and what types will not. That would be
> a big investigation and I see no reason to do it because there
> are other chips.
> 
> The R820T gives good signals many times but I do not like the feeling
> of not knowing what I am doing.....
> 
> The "internal AGC" option is another thing as far as I understand.
> The chip has RF AGC as well as IF AGC.
> 
> 73
> 
> Leif / SM5BSZ
> 
> > Hello Group,
> > 
> > When using a DVB-T type dongle (mine is a R820T), do you tick the
> "internal AGC" option or not ?
> > 
> > I tried both "internal AGC" desactivated (with more gain) and AGC
> activated (less gain to avoid spurs from my local FM TX) ... I can't tell
> which one is better. Even on weakish sigs it's about the same.
> > 
> > What about your experience ?
> > 
> > Regards,
> > Patrick
> > 
> 
> 
> 



From sdrguru1 at gmail.com  Mon Aug 12 08:43:52 2013
From: sdrguru1 at gmail.com (Sdr Guru)
Date: Mon, 12 Aug 2013 11:43:52 +0300
Subject: About 'internal AGC'
In-Reply-To: <20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
Message-ID: <CACR-see9SZA=H0N_BvN9p5qG5beqaW0oKb7z=ZYgJFEzKaBkkQ@mail.gmail.com>

Hi

This explains why the FM trap filter helps so much.
Especially in the VHF band when the FM transmitters are nearby (city).

SG

On Sun, Aug 11, 2013 at 11:48 PM, Leif Asbrink <leif at sm5bsz.com> wrote:

> Hi Charlie,
>
> The controls for AGC do not affect the peculiar wideband LNA AGC
> in the R820T chip. The RTL1090 uses the same rtlsdr.dll as is
> used by SDR#. I do not know how to evaluate noise levels and signal
> levels in RTL1090, but with SDR# one can see funny things
> directly on the waterfall.
>
> The LNA is followed by a VERY sensitive power detector that
> is somehow followed by filters and amplifiers. It is arranged
> in a way to not react on narrowband signals, but already a 3 dB
> increase of the noise floor causes a loss of gain through AGC
> action.
>
> Most striking is this experiment:
>
> Connect a combiner to the input of the dongle and use it to
> combine a signal generator and a noise source. The noise
> source needs a filter that assures that it does not add any noise
> on the frequency of the desired signal. It is OK to use a
> T-connector if you do not have a wideband combiner.
>
> I used a 100 MHz low pass filter connected to a vacuum diode
> noise source cabable of delivering 17 dB excess noise combined
> with a signal generator on 144 MHz by use of a T connector.
>
> I used SDR# to look at the spectrum around 144 MHz.
>
> Without "RTL AGC" and without "Tuner AGC" the noise floor does not
> change when the noise source is switched on or off. That is expected
> because the noise source can not send any noise through the 100 MHz
> low pass filter. That is true at modest gain settings, but if
> the gain is set at maximum (49.6 dB) the noise floor increases by 3 dB
> when the noise source is turned on. A small but unexpected effect.
>
> The signal however is attenuated by 23 dB for a total loss at max
> gain of S/N of 26 dB!!!!! Please note that the true S/N is not affected
> at all. There is no noise added at 144 MHz.
>
> If I switch on "RTL AGC" or "Tuner AGC" or both, S/N still changes
> the same way. Depending on the signal level of the 144 MHz signal
> one can see the signal go down or the noise go up. Or both.
>
> The way sensitivity is lost due to out-of-band noise is invisible
> to the user. There is no warning about overload.
>
> The noise power from 0 to 100 MHz is -174+17+80 = -77 dBm
> ( -174 dBm/Hz = room temp)
> ( +17 dB is excess noise)
> ( +80dB is 100/MHz/1Hz)
> There is some filter loss and the dongle presumably has a high pass
> filter so one can assume that the noise power is -80 dBm RMS.
>
> I have tried to activate the LNA AGC by use of narrowband
> signals in the 50 to 100 MHz range. Even two signals at
> -30 dBm each do not have any effect regardless of the frequency
> spacing. It seems the "intelligent" power detector of the LNA
> AGC can reject narrowband signals even if they are much
> stronger than the noise floor.
>
> The wideband LNA AGC in the R820T may cause problems when
> an up-converter is used in front of the dongle. The noise floor
> of the up-converted HF spectrum may cause unexpected loss of
> sensitivity in the upper part of the HF spectrum where the
> noise floor is low.
>
> Adding a filter for the desired HF band. With some gain to
> ensure that the noise floor is higher in the desired frequency
> range than elsewhere could perhaps make the R820T dongles
> behave much better.
>
> 73
>
> Leif  /  SM5BSZ
>
>
>
>
>
>
> > I use a R820T chipped dongle for receiving aircraft transponder signals
> > through a specialised application called RTL1090 from jetvision, the
> control
> > panel of which allows the tuner and device AGCs to be independently
> toggled
> > on or off. I have not however used this with SDR-Radio in the past so
> cannot
> > comment on the optimum settings.
> >
> >
> >
> > 73
> >
> > Charlie
> >
> > www.G4EST.me.uk
> >
> >
> >
> > From: sdr-radio-com at yahoogroups.com [mailto:
> sdr-radio-com at yahoogroups.com]
> > On Behalf Of Leif Asbrink
> > Sent: 10 August 2013 22:30
> > To: sdr-radio-com at yahoogroups.com
> > Subject: [sdr-radio-com] Re: About 'internal AGC'
> >
> >
> >
> >
> >
> > Hello Patrick and All,
> >
> > The R820T chip has an advanced AGC function that I do not
> > think can be disabled. The chip detects the noise floor
> > in a wide bandwidth and adjusts the gain to keep the noise floor
> > constant.
> >
> > The wideband AGC has surprising effects. If one tries to measure
> > the noise figure with a noise source that is manually switched
> > on and off one finds a really bad NF. That result is false however,
> > if one measures S/N of a weak signal one finds the true NF which
> > is quite good.
> >
> > To verify the finding one can inject a weak signal together
> > with the signal from a noise source. What happens when the
> > noise is turned on is that the signal becomes weaker while
> > the noise floor does not change.
> >
> > A 500 kHz wide filter in front of the R820T chip converts the
> > noise from the noise source to a narrowband signal which will
> > not affect the wideband AGC.
> >
> > I made some effort to switch this feature off but failed.
> >
> > The behaviour is probably quite clever for reception of digital TV
> > but I find it very disturbing in a general purpose SDR. I did not
> > take notes and I did not investigate in detail what types of signals
> > will affect the AGC and what types will not. That would be
> > a big investigation and I see no reason to do it because there
> > are other chips.
> >
> > The R820T gives good signals many times but I do not like the feeling
> > of not knowing what I am doing.....
> >
> > The "internal AGC" option is another thing as far as I understand.
> > The chip has RF AGC as well as IF AGC.
> >
> > 73
> >
> > Leif / SM5BSZ
> >
> > > Hello Group,
> > >
> > > When using a DVB-T type dongle (mine is a R820T), do you tick the
> > "internal AGC" option or not ?
> > >
> > > I tried both "internal AGC" desactivated (with more gain) and AGC
> > activated (less gain to avoid spurs from my local FM TX) ... I can't tell
> > which one is better. Even on weakish sigs it's about the same.
> > >
> > > What about your experience ?
> > >
> > > Regards,
> > > Patrick
> > >
> >
> >
> >
>
>
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From anton.komarov at gmail.com  Mon Aug 12 14:55:22 2013
From: anton.komarov at gmail.com (Anton Komarov)
Date: Mon, 12 Aug 2013 18:55:22 +0400
Subject: Debian Jessie and kernel 3.9.1
Message-ID: <CAHKdsmRS3oPJjvXx1zwAUkD_YwbtWzM7G=ZSBQD0sGZTER9=rw@mail.gmail.com>

Tested several rtl dongles with linux 3.9.1 on Debian Jessie (testing)
and got disappointing results
2 dongles simultaneously working ok
if using 3 or more than 3rd dongle not working (1st and 2nd working ok)

in Debian Wheezy i did manage to run 5 dongles simultaneously (kernel 3.2)
i suppose  developers should pay attention to than fact.
--
public PGP key
http://pastebin.com/dqZqgyVE
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From 246tnt at gmail.com  Mon Aug 12 15:09:54 2013
From: 246tnt at gmail.com (Sylvain Munaut)
Date: Mon, 12 Aug 2013 17:09:54 +0200
Subject: Debian Jessie and kernel 3.9.1
In-Reply-To: <CAHKdsmRS3oPJjvXx1zwAUkD_YwbtWzM7G=ZSBQD0sGZTER9=rw@mail.gmail.com>
References: <CAHKdsmRS3oPJjvXx1zwAUkD_YwbtWzM7G=ZSBQD0sGZTER9=rw@mail.gmail.com>
Message-ID: <CAHL+j0-b84HUbP3d+vDcc6+g8DKCohbYpJPrASj1S6mkyr7Qig@mail.gmail.com>

On Mon, Aug 12, 2013 at 4:55 PM, Anton Komarov <anton.komarov at gmail.com> wrote:
> Tested several rtl dongles with linux 3.9.1 on Debian Jessie (testing)
> and got disappointing results
> 2 dongles simultaneously working ok
> if using 3 or more than 3rd dongle not working (1st and 2nd working ok)
>
> in Debian Wheezy i did manage to run 5 dongles simultaneously (kernel 3.2)
> i suppose  developers should pay attention to than fact.

Tell that to the kernel dev ...


Cheers,

    Sylvain



From leif at sm5bsz.com  Mon Aug 12 21:48:49 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Mon, 12 Aug 2013 23:48:49 +0200
Subject: False alarm about 'internal AGC' in R820T
In-Reply-To: <CACR-see9SZA=H0N_BvN9p5qG5beqaW0oKb7z=ZYgJFEzKaBkkQ@mail.gmail.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
	<CACR-see9SZA=H0N_BvN9p5qG5beqaW0oKb7z=ZYgJFEzKaBkkQ@mail.gmail.com>
Message-ID: <20130812234849.03c1aafae178bf46a7c7f21b@sm5bsz.com>

Hi All,

I falsely interpreted the phenomenon I described as an
action of the LNA AGC. It is a striking effect experimentally,
but tha cause is not the noise generated by the temperature
limited vacuum diode. As it turns out, the phenomenon is
caused by the DC, about -1.3 V, that is present at the output of
my Magnetic type 123 noise source. 

Obviously the designers of the ezcap USB 2.0 DVB-T/DAB/FM dongle
decided they could save a cent or so by not adding a DC blocking
capacitor on the input....

The data sheet I have indeed tells that there is a wideband LNA 
AGC but is does not behave as I was misled to believe on the basis
of experiments with the 123 noise source.


73

Leif  /  SM5BSZ


> > Hi Charlie,
> >
> > The controls for AGC do not affect the peculiar wideband LNA AGC
> > in the R820T chip. The RTL1090 uses the same rtlsdr.dll as is
> > used by SDR#. I do not know how to evaluate noise levels and signal
> > levels in RTL1090, but with SDR# one can see funny things
> > directly on the waterfall.
> >
> > The LNA is followed by a VERY sensitive power detector that
> > is somehow followed by filters and amplifiers. It is arranged
> > in a way to not react on narrowband signals, but already a 3 dB
> > increase of the noise floor causes a loss of gain through AGC
> > action.
> >
> > Most striking is this experiment:
> >
> > Connect a combiner to the input of the dongle and use it to
> > combine a signal generator and a noise source. The noise
> > source needs a filter that assures that it does not add any noise
> > on the frequency of the desired signal. It is OK to use a
> > T-connector if you do not have a wideband combiner.
> >
> > I used a 100 MHz low pass filter connected to a vacuum diode
> > noise source cabable of delivering 17 dB excess noise combined
> > with a signal generator on 144 MHz by use of a T connector.
> >
> > I used SDR# to look at the spectrum around 144 MHz.
> >
> > Without "RTL AGC" and without "Tuner AGC" the noise floor does not
> > change when the noise source is switched on or off. That is expected
> > because the noise source can not send any noise through the 100 MHz
> > low pass filter. That is true at modest gain settings, but if
> > the gain is set at maximum (49.6 dB) the noise floor increases by 3 dB
> > when the noise source is turned on. A small but unexpected effect.
> >
> > The signal however is attenuated by 23 dB for a total loss at max
> > gain of S/N of 26 dB!!!!! Please note that the true S/N is not affected
> > at all. There is no noise added at 144 MHz.
> >
> > If I switch on "RTL AGC" or "Tuner AGC" or both, S/N still changes
> > the same way. Depending on the signal level of the 144 MHz signal
> > one can see the signal go down or the noise go up. Or both.
> >
> > The way sensitivity is lost due to out-of-band noise is invisible
> > to the user. There is no warning about overload.
> >
> > The noise power from 0 to 100 MHz is -174+17+80 = -77 dBm
> > ( -174 dBm/Hz = room temp)
> > ( +17 dB is excess noise)
> > ( +80dB is 100/MHz/1Hz)
> > There is some filter loss and the dongle presumably has a high pass
> > filter so one can assume that the noise power is -80 dBm RMS.
> >
> > I have tried to activate the LNA AGC by use of narrowband
> > signals in the 50 to 100 MHz range. Even two signals at
> > -30 dBm each do not have any effect regardless of the frequency
> > spacing. It seems the "intelligent" power detector of the LNA
> > AGC can reject narrowband signals even if they are much
> > stronger than the noise floor.
> >
> > The wideband LNA AGC in the R820T may cause problems when
> > an up-converter is used in front of the dongle. The noise floor
> > of the up-converted HF spectrum may cause unexpected loss of
> > sensitivity in the upper part of the HF spectrum where the
> > noise floor is low.
> >
> > Adding a filter for the desired HF band. With some gain to
> > ensure that the noise floor is higher in the desired frequency
> > range than elsewhere could perhaps make the R820T dongles
> > behave much better.
> >
> > 73
> >
> > Leif  /  SM5BSZ
> >
> >
> >
> >
> >
> >
> > > I use a R820T chipped dongle for receiving aircraft transponder signals
> > > through a specialised application called RTL1090 from jetvision, the
> > control
> > > panel of which allows the tuner and device AGCs to be independently
> > toggled
> > > on or off. I have not however used this with SDR-Radio in the past so
> > cannot
> > > comment on the optimum settings.
> > >
> > >
> > >
> > > 73
> > >
> > > Charlie
> > >
> > > www.G4EST.me.uk
> > >
> > >
> > >
> > > From: sdr-radio-com at yahoogroups.com [mailto:
> > sdr-radio-com at yahoogroups.com]
> > > On Behalf Of Leif Asbrink
> > > Sent: 10 August 2013 22:30
> > > To: sdr-radio-com at yahoogroups.com
> > > Subject: [sdr-radio-com] Re: About 'internal AGC'
> > >
> > >
> > >
> > >
> > >
> > > Hello Patrick and All,
> > >
> > > The R820T chip has an advanced AGC function that I do not
> > > think can be disabled. The chip detects the noise floor
> > > in a wide bandwidth and adjusts the gain to keep the noise floor
> > > constant.
> > >
> > > The wideband AGC has surprising effects. If one tries to measure
> > > the noise figure with a noise source that is manually switched
> > > on and off one finds a really bad NF. That result is false however,
> > > if one measures S/N of a weak signal one finds the true NF which
> > > is quite good.
> > >
> > > To verify the finding one can inject a weak signal together
> > > with the signal from a noise source. What happens when the
> > > noise is turned on is that the signal becomes weaker while
> > > the noise floor does not change.
> > >
> > > A 500 kHz wide filter in front of the R820T chip converts the
> > > noise from the noise source to a narrowband signal which will
> > > not affect the wideband AGC.
> > >
> > > I made some effort to switch this feature off but failed.
> > >
> > > The behaviour is probably quite clever for reception of digital TV
> > > but I find it very disturbing in a general purpose SDR. I did not
> > > take notes and I did not investigate in detail what types of signals
> > > will affect the AGC and what types will not. That would be
> > > a big investigation and I see no reason to do it because there
> > > are other chips.
> > >
> > > The R820T gives good signals many times but I do not like the feeling
> > > of not knowing what I am doing.....
> > >
> > > The "internal AGC" option is another thing as far as I understand.
> > > The chip has RF AGC as well as IF AGC.
> > >
> > > 73
> > >
> > > Leif / SM5BSZ
> > >
> > > > Hello Group,
> > > >
> > > > When using a DVB-T type dongle (mine is a R820T), do you tick the
> > > "internal AGC" option or not ?
> > > >
> > > > I tried both "internal AGC" desactivated (with more gain) and AGC
> > > activated (less gain to avoid spurs from my local FM TX) ... I can't tell
> > > which one is better. Even on weakish sigs it's about the same.
> > > >
> > > > What about your experience ?
> > > >
> > > > Regards,
> > > > Patrick
> > > >
> > >
> > >
> > >
> >
> >
> 
> -- 
> You received this message because you are subscribed to the Google Groups "Ultra Cheap SDR" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to ultra-cheap-sdr+unsubscribe at googlegroups.com.
> To post to this group, send email to ultra-cheap-sdr at googlegroups.com.
> Visit this group at http://groups.google.com/group/ultra-cheap-sdr.
> For more options, visit https://groups.google.com/groups/opt_out.



From leif at sm5bsz.com  Wed Aug 14 12:00:51 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Wed, 14 Aug 2013 14:00:51 +0200
Subject: Comparing tuners.
In-Reply-To: <20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
Message-ID: <20130814140051.054897bde1bcc0c26ee0c605@sm5bsz.com>

Hi All,

The rtlsdr dongles come with different tuner chips.
Have a look at this video:
http://www.youtube.com/watch?v=cVU5X1d2XYU

Four dongles are run simultaneously with the same input
signal. A seven port resistive combiner is used to combine
a noise source, a signal generator and a sweep generator
and to distribute the combined signal to the four dongles.

The screen shows three instances of SDRsharp running the 
three tuners plur one instance of Linrad with the E4000
tuner for which Linrad allows a different gain distribution
that provides a much better suppression of false signals.

The Linrad screen is pixel-oriented so the video should
be looked at with high quality.

Regards

Leif / SM5BSZ



From leif at sm5bsz.com  Thu Aug 15 03:06:24 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Thu, 15 Aug 2013 05:06:24 +0200
Subject: About 'internal AGC'
In-Reply-To: <a339def8-031f-4444-87a1-1821a08967a4@googlegroups.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
	<a339def8-031f-4444-87a1-1821a08967a4@googlegroups.com>
Message-ID: <20130815050624.3e59e26e5b3de0ef7aba266c@sm5bsz.com>

On Wed, 14 Aug 2013 19:55:03 -0700 (PDT)
m240zz at gmail.com wrote:

> yes, I am afraid you are assuming all of us are as smart as you on the 
> topic so if you have time please have another go at it. You are in a 
> unique position to do this since you have all the equpiment at hand.
OK. I will try to make things more clear.

>  The thing that confuses me is why is it during the sweeps due the fft look 
> so different in each of the windows  and it seems like the timing of the 
> sweeps are different.  The sweeps happen at the same time for each dongle, 
> right?  The dongles  are all listening in parallel at the same time?  If 
> so, seems like they would look more alike at the same time.  My apologies 
> for the density on this end.
The dongles suffer from various problems. Overload and inadequate anti-alias 
filtering. A lot of false signals are generated but that is different 
between the different dongles.

The input is identical to all the dongles and you can see that in the beginning
of the video where signal levels are low. At high signal levels they
behave quite differently because false signals dominate (But not in Linrad.)

73

Leif / SM5BSZ



From m240zz at gmail.com  Thu Aug 15 02:55:03 2013
From: m240zz at gmail.com (m240zz at gmail.com)
Date: Wed, 14 Aug 2013 19:55:03 -0700 (PDT)
Subject: About 'internal AGC'
In-Reply-To: <20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
Message-ID: <a339def8-031f-4444-87a1-1821a08967a4@googlegroups.com>

yes, I am afraid you are assuming all of us are as smart as you on the 
topic so if you have time please have another go at it.   You are in a 
unique position to do this since you have all the equpiment at hand.

 The thing that confuses me is why is it during the sweeps due the fft look 
so different in each of the windows  and it seems like the timing of the 
sweeps are different.  The sweeps happen at the same time for each dongle, 
right?  The dongles  are all listening in parallel at the same time?  If 
so, seems like they would look more alike at the same time.  My apologies 
for the density on this end.

73 wa5ngp
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From m240zz at gmail.com  Thu Aug 15 12:42:08 2013
From: m240zz at gmail.com (m240zz at gmail.com)
Date: Thu, 15 Aug 2013 05:42:08 -0700 (PDT)
Subject: About 'internal AGC'
In-Reply-To: <20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
Message-ID: <cfbdeedd-bfbd-4811-8b8a-fd69ff11be23@googlegroups.com>

thanks for all the explanations.  Since I'm new to this I was thinking I 
was missing something bigtime.  I guess not.  I was expecting to see a 
single spike sweeping thru there.  When I saw all that stuff it kinda 
reminded me of the intermod that you see on vhf stuff where several 
frequency  signals beat together to make an image back on the channel that 
you are listening to.  Based on those results I am surprised that the whole 
thing is usable as a receiver but I suppose real life listening there 
aren't that many strong signals that create those artifacts.

Somehow on my screen the linrad thing was not very visible due to contrast 
or something so I couldn't quite tell what I was looking at.

If the bandwidth &/or gain  is turned way down, say 200 khz window, do 
those false signals due to the sweep and subsequent aliasing  get minimized?

73 don

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From leif at sm5bsz.com  Sat Aug 17 23:10:49 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Sun, 18 Aug 2013 01:10:49 +0200
Subject: About 'internal AGC'
In-Reply-To: <a339def8-031f-4444-87a1-1821a08967a4@googlegroups.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
	<a339def8-031f-4444-87a1-1821a08967a4@googlegroups.com>
Message-ID: <20130818011049.b67791ef84c5f97de9236b17@sm5bsz.com>

On Wed, 14 Aug 2013 19:55:03 -0700 (PDT)
m240zz at gmail.com wrote:

>  The thing that confuses me is why is it during the sweeps due the fft look 
> so different in each of the windows  and it seems like the timing of the 
> sweeps are different.  The sweeps happen at the same time for each dongle, 
> right?  The dongles  are all listening in parallel at the same time?  If 
> so, seems like they would look more alike at the same time.  My apologies 
> for the density on this end.

The purpose of the vido was to demonstrate that dongles are different.
The sweeps indeed happen at the same time for all the dongles. The very
point is that they do not look very much alike. It is non-trivial
to know in advance which one will perform best in a real life
situation.

It was the first video. It just shows that dongles are (very) different.
I am uploading some more videos as a response to the feedback I received
so far. (Upload is extremely slow from here...)

It would be trivial, but it would take a lot of time, to use a dongle
to provide a wideband map from 50 to 500 MHz or whatever on a particular
antenna in a particular location. With that knowledge it would be easier to
decide what dongle to choose for a particular situation. It is trivial
to add a selective filter and that can make a big difference for the
dongles.

73

Leif





From keenerd at gmail.com  Sun Aug 18 05:43:14 2013
From: keenerd at gmail.com (keenerd)
Date: Sun, 18 Aug 2013 01:43:14 -0400
Subject: OpenBSD: crashing
In-Reply-To: <20130510072456.GN28210@symphytum.spacehopper.org>
References: <1366172088.84920.YahooMailNeo@web161502.mail.bf1.yahoo.com>
	<slrnkn2ek2.9sa.stu@naiad.spacehopper.org>
	<1366430374.52532.YahooMailNeo@web161504.mail.bf1.yahoo.com>
	<518B88F0.2060400@fiane.dyndns.org>
	<20130510072456.GN28210@symphytum.spacehopper.org>
Message-ID: <CAAKTTKOzhn5FHuSyFj+cxc8yUpU0BNd1a4=6U1Z+_d-1XHTDCQ@mail.gmail.com>

I think I've fixed all the problems with rtl_fm. ?It does not use the
async helper functions any more. ?For my purposes async mode is
broken. ?No clue what happened, but when you re-turn it freezes up on
rtlsdr_demod_read_reg(dev, 0x0a, 0x01, 1); line 476 of librtlsdr.c.
The new code is still multithreaded and should be just as fast.

My patch is at
https://github.com/keenerd/rtl-sdr

It would be nice to hear if this fixes the OpenBSD problems, and a
confirmation that the new code still runs under windows.

-Kyle
http://kmkeen.com



From peter at stuge.se  Sun Aug 18 15:49:44 2013
From: peter at stuge.se (Peter Stuge)
Date: Sun, 18 Aug 2013 17:49:44 +0200
Subject: OpenBSD: crashing
In-Reply-To: <CAAKTTKOzhn5FHuSyFj+cxc8yUpU0BNd1a4=6U1Z+_d-1XHTDCQ@mail.gmail.com>
References: <1366172088.84920.YahooMailNeo@web161502.mail.bf1.yahoo.com>
	<slrnkn2ek2.9sa.stu@naiad.spacehopper.org>
	<1366430374.52532.YahooMailNeo@web161504.mail.bf1.yahoo.com>
	<518B88F0.2060400@fiane.dyndns.org>
	<20130510072456.GN28210@symphytum.spacehopper.org>
	<CAAKTTKOzhn5FHuSyFj+cxc8yUpU0BNd1a4=6U1Z+_d-1XHTDCQ@mail.gmail.com>
Message-ID: <20130818154944.22293.qmail@stuge.se>

keenerd wrote:
> I think I've fixed all the problems with rtl_fm. ?It does not use
> the async helper functions any more. ?For my purposes async mode
> is broken. ?No clue what happened, but when you re-turn it freezes
> up on rtlsdr_demod_read_reg(dev, 0x0a, 0x01, 1); line 476 of librtlsdr.c.

The OpenBSD kernel doesn't currently offer any async API that libusb
can use, so libusb has to emulate the async behavior as best it can,
and it is by no means perfect.

If you have a chance, I would very much like to work with you today,
tomorrow and/or on Tuesday in order to look more closely into this.
I have some ideas if you are up for it? After Tuesday I have no
chance for a few weeks or so.


//Peter



From keenerd at gmail.com  Sun Aug 18 17:15:54 2013
From: keenerd at gmail.com (keenerd)
Date: Sun, 18 Aug 2013 13:15:54 -0400
Subject: OpenBSD: crashing
In-Reply-To: <20130818154944.22293.qmail@stuge.se>
References: <1366172088.84920.YahooMailNeo@web161502.mail.bf1.yahoo.com>
	<slrnkn2ek2.9sa.stu@naiad.spacehopper.org>
	<1366430374.52532.YahooMailNeo@web161504.mail.bf1.yahoo.com>
	<518B88F0.2060400@fiane.dyndns.org>
	<20130510072456.GN28210@symphytum.spacehopper.org>
	<CAAKTTKOzhn5FHuSyFj+cxc8yUpU0BNd1a4=6U1Z+_d-1XHTDCQ@mail.gmail.com>
	<20130818154944.22293.qmail@stuge.se>
Message-ID: <CAAKTTKPwc-VrWq3VkFmuJ-A=TbaPHumcHPew2m=GJWmCUuD8ag@mail.gmail.com>

On 8/18/13, Peter Stuge <peter at stuge.se> wrote:
> If you have a chance, I would very much like to work with you today,
> tomorrow and/or on Tuesday in order to look more closely into this.
> I have some ideas if you are up for it?

Sure, I'll be in ##rtlsdr on Freenode today.  Not sure how much help I
can be though.  I still don't know much about libusb or librtlsdr yet.

-Kyle
http://kmkeen.com



From 1cjcarpenter at att.net  Mon Aug 19 21:02:25 2013
From: 1cjcarpenter at att.net (Curt Carpenter)
Date: Mon, 19 Aug 2013 16:02:25 -0500
Subject: Is My RTL2838U + R820T Tuner working?
Message-ID: <521287E1.4040505@att.net>

Hello!

I received my USB-DVB-T+DAB+FM dongle last week, and have been trying to 
find a signal with it since, but with no luck.  Can anyone tell me how 
to tell if it is working at all?

I'm using the Windows version of Osmocom under WinXP.

Using rtl_eeprom, I get the following display:
--------------------------

Vendor ID                               0x0bda
Product ID                              0x2838
Manufacturer                          Realtek
Product                                   RTL2838UHIDIR
Serial Number                        00000000001
Serial Number Enabled        Yes
IR Endpoint Enabled             Yes
Remote Wakeup Enabled     No

-----------------------

When I run

rtl_test -s 1.6e6

I get the following response:

-----------------------

Found 1 device(s)
    0:  ezcap USB 2.0 DVB-T/DAB/FM dongle
Using device 0:  ezcap USB 2.0 DVB-T/DAB/FM dongle
Supported gain values(29):  0.0 0.9 .... 49.6
Info:  This tool will continuously read from the device, and report if 
samples get lost.
If you observer no further output, everything is fine.

Reading samples in async mode...

--------------------------

If at that point after a while I press Control C, I get

---------------------------

Signal caught, exiting!

---------------------------

But then my command prompt window hangs up and will do nothing until I 
close it all together.

Does it appear that my dongle is working?  Where do I find out how to 
use the different gains that are listed by rtl_test?  Could my 
difficulties have anything to do with the fact that my dongle is IR 
Endpoint enabled?

I am brand new to this, and haven't had much luck so far, although I 
think I've gotten further with Osmocom and Windows than with anything 
else I've tried.  Any help/advice/links to more information will be much 
appreciated.  Sorry for the long post -- I was trying to provide as much 
information as I could.


Thanks
Curt Carpenter





From slothpuck at gmail.com  Mon Aug 19 22:59:47 2013
From: slothpuck at gmail.com (lee jones)
Date: Mon, 19 Aug 2013 22:59:47 +0000
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoKj4a6Z7t+t5i=E20Jx7FF9Wtdq9Y_SxP2TpLdJKxgFyA@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
	<CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
	<CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
	<CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
	<20130805111841.11860.qmail@stuge.se>
	<CAKwpmoKj4a6Z7t+t5i=E20Jx7FF9Wtdq9Y_SxP2TpLdJKxgFyA@mail.gmail.com>
Message-ID: <CAKwpmoKQcv4hFbSF_fM-ZVPbMZQ6B3-iOuKD8tOmA7B+aDzOaA@mail.gmail.com>

On 8/5/13, lee jones <slothpuck at gmail.com> wrote:
>>It would be interesting to see the output from a run that uses
>>libusb-1.0.9 or better yet the code from libusb.git
>
> Should I apt-get remove the libusb (libusbx) before I try this or
> leave it installed?
>
>>Hi, Which version of Debian are you using?
> I'm using debian 7 but upgraded. Looking at /etc/debian_version it
> reports "jessie/sid".
>
> ljones
>



I've still not tried this btw. If I remove libusb-1.0-0 it appears it
will break all manner of stuff x.x . Is there any sort of workaround
possible?

ljones



From skip.tavakkolian at gmail.com  Mon Aug 19 23:03:43 2013
From: skip.tavakkolian at gmail.com (Skip Tavakkolian)
Date: Mon, 19 Aug 2013 16:03:43 -0700
Subject: Is My RTL2838U + R820T Tuner working?
In-Reply-To: <521287E1.4040505@att.net>
References: <521287E1.4040505@att.net>
Message-ID: <78E7D7B1-07EB-468F-BD0D-C4E4FD296B4F@gmail.com>

For a quick sanity check I use rtl_fm to tune into a local FM station. Here is a good guide for rtl_fm:

http://kmkeen.com/rtl-demod-guide/index.html


On Aug 19, 2013, at 2:02 PM, Curt Carpenter <1cjcarpenter at att.net> wrote:

> Hello!
> 
> I received my USB-DVB-T+DAB+FM dongle last week, and have been trying to find a signal with it since, but with no luck.  Can anyone tell me how to tell if it is working at all?
> 
> I'm using the Windows version of Osmocom under WinXP.
> 
> Using rtl_eeprom, I get the following display:
> --------------------------
> 
> Vendor ID                               0x0bda
> Product ID                              0x2838
> Manufacturer                          Realtek
> Product                                   RTL2838UHIDIR
> Serial Number                        00000000001
> Serial Number Enabled        Yes
> IR Endpoint Enabled             Yes
> Remote Wakeup Enabled     No
> 
> -----------------------
> 
> When I run
> 
> rtl_test -s 1.6e6
> 
> I get the following response:
> 
> -----------------------
> 
> Found 1 device(s)
>   0:  ezcap USB 2.0 DVB-T/DAB/FM dongle
> Using device 0:  ezcap USB 2.0 DVB-T/DAB/FM dongle
> Supported gain values(29):  0.0 0.9 .... 49.6
> Info:  This tool will continuously read from the device, and report if samples get lost.
> If you observer no further output, everything is fine.
> 
> Reading samples in async mode...
> 
> --------------------------
> 
> If at that point after a while I press Control C, I get
> 
> ---------------------------
> 
> Signal caught, exiting!
> 
> ---------------------------
> 
> But then my command prompt window hangs up and will do nothing until I close it all together.
> 
> Does it appear that my dongle is working?  Where do I find out how to use the different gains that are listed by rtl_test?  Could my difficulties have anything to do with the fact that my dongle is IR Endpoint enabled?
> 
> I am brand new to this, and haven't had much luck so far, although I think I've gotten further with Osmocom and Windows than with anything else I've tried.  Any help/advice/links to more information will be much appreciated.  Sorry for the long post -- I was trying to provide as much information as I could.
> 
> 
> Thanks
> Curt Carpenter
> 
> 
> 
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From peter at stuge.se  Mon Aug 19 23:10:49 2013
From: peter at stuge.se (Peter Stuge)
Date: Tue, 20 Aug 2013 01:10:49 +0200
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <CAKwpmoKQcv4hFbSF_fM-ZVPbMZQ6B3-iOuKD8tOmA7B+aDzOaA@mail.gmail.com>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
	<CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
	<CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
	<CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
	<20130805111841.11860.qmail@stuge.se>
	<CAKwpmoKj4a6Z7t+t5i=E20Jx7FF9Wtdq9Y_SxP2TpLdJKxgFyA@mail.gmail.com>
	<CAKwpmoKQcv4hFbSF_fM-ZVPbMZQ6B3-iOuKD8tOmA7B+aDzOaA@mail.gmail.com>
Message-ID: <20130819231049.4732.qmail@stuge.se>

lee jones wrote:
> >>It would be interesting to see the output from a run that uses
> >>libusb-1.0.9 or better yet the code from libusb.git
> 
> I've still not tried this btw. If I remove libusb-1.0-0 it appears it
> will break all manner of stuff x.x . Is there any sort of workaround
> possible?

Use the principle documented at http://libusb.org/wiki/debug


//Peter



From lucas.lorenzi at gmail.com  Tue Aug 20 02:44:51 2013
From: lucas.lorenzi at gmail.com (Lucas Ingles)
Date: Mon, 19 Aug 2013 23:44:51 -0300
Subject: How RTL-SDR samples signals
Message-ID: <CAHA_kS1bzP5avxn8QdODBnFd2EFETTHgXyA4iLJsjj-vLTMPMw@mail.gmail.com>

Hello to all,

Please, can someone help me to understand how RTL2832U samples signals?
I know it has two ADCs, one for the I (in-phase) component and other ADC
for the Q (quadrature) component.

In http://superkuh.com/rtlsdr.html the author states the signal is sampled
initially at 28.8 Msps and then re sampled to present whatever sample rate
is desired.

But
http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=35&Level=4&Conn=3&ProdID=257
says
that 28.8MHz is the frequency of the crystal, not the ADC.

I am confused with that, can someone help me?
If RTL2832U is able to sample at 28.8Msps, why don't use the maximum sample
rate? Maybe USB limitations?

Also, all ADCs used in RTL-SDR dongles are inside RTL2832U? Or we have
external ADCs?

Thanks very much in advance,
Lucas Ingles
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From 1cjcarpenter at att.net  Tue Aug 20 02:48:21 2013
From: 1cjcarpenter at att.net (Curt Carpenter)
Date: Mon, 19 Aug 2013 21:48:21 -0500
Subject: Is My RTL2838U + R820T Tuner working?
In-Reply-To: <78E7D7B1-07EB-468F-BD0D-C4E4FD296B4F@gmail.com>
References: <521287E1.4040505@att.net>
	<78E7D7B1-07EB-468F-BD0D-C4E4FD296B4F@gmail.com>
Message-ID: <5212D8F5.9000404@att.net>

Thanks for the link Skip.  I used the first example in the guide (with 
freq changed to a known local FM station) as

rtl_fm -W -f 90.1M | play -r 32k -t raw -e signed-integer -b 16 -c 1 -V1 -

but all I am able to hear is noise.  So I'm still stuck wondering if my 
dongle is working or not since I can't get any signals at all -- only noise.

I get two messages that look like the may indicate a problem:

"[R820T] PLL not locked for 3926090 Hz"

and

"WARNING:  Failed to set center frequency."

Any idea what these mean?

On 8/19/2013 6:03 PM, Skip Tavakkolian wrote:
> For a quick sanity check I use rtl_fm to tune into a local FM station. 
> Here is a good guide for rtl_fm:
>
> http://kmkeen.com/rtl-demod-guide/index.html
>
>
> On Aug 19, 2013, at 2:02 PM, Curt Carpenter <1cjcarpenter at att.net 
> <mailto:1cjcarpenter at att.net>> wrote:
>
>> Hello!
>>
>> I received my USB-DVB-T+DAB+FM dongle last week, and have been trying 
>> to find a signal with it since, but with no luck.  Can anyone tell me 
>> how to tell if it is working at all?
>>
>> I'm using the Windows version of Osmocom under WinXP.
>>
>> Using rtl_eeprom, I get the following display:
>> --------------------------
>>
>> Vendor ID                               0x0bda
>> Product ID                              0x2838
>> Manufacturer                          Realtek
>> Product                                   RTL2838UHIDIR
>> Serial Number                        00000000001
>> Serial Number Enabled        Yes
>> IR Endpoint Enabled             Yes
>> Remote Wakeup Enabled     No
>>
>> -----------------------
>>
>> When I run
>>
>> rtl_test -s 1.6e6
>>
>> I get the following response:
>>
>> -----------------------
>>
>> Found 1 device(s)
>>   0:  ezcap USB 2.0 DVB-T/DAB/FM dongle
>> Using device 0:  ezcap USB 2.0 DVB-T/DAB/FM dongle
>> Supported gain values(29):  0.0 0.9 .... 49.6
>> Info:  This tool will continuously read from the device, and report 
>> if samples get lost.
>> If you observer no further output, everything is fine.
>>
>> Reading samples in async mode...
>>
>> --------------------------
>>
>> If at that point after a while I press Control C, I get
>>
>> ---------------------------
>>
>> Signal caught, exiting!
>>
>> ---------------------------
>>
>> But then my command prompt window hangs up and will do nothing until 
>> I close it all together.
>>
>> Does it appear that my dongle is working?  Where do I find out how to 
>> use the different gains that are listed by rtl_test?  Could my 
>> difficulties have anything to do with the fact that my dongle is IR 
>> Endpoint enabled?
>>
>> I am brand new to this, and haven't had much luck so far, although I 
>> think I've gotten further with Osmocom and Windows than with anything 
>> else I've tried.  Any help/advice/links to more information will be 
>> much appreciated.  Sorry for the long post -- I was trying to provide 
>> as much information as I could.
>>
>>
>> Thanks
>> Curt Carpenter
>>
>>
>>

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From davidb-sdr at rcpt.to  Tue Aug 20 03:17:34 2013
From: davidb-sdr at rcpt.to (David Basden)
Date: Tue, 20 Aug 2013 13:17:34 +1000
Subject: How RTL-SDR samples signals
In-Reply-To: <CAHA_kS1bzP5avxn8QdODBnFd2EFETTHgXyA4iLJsjj-vLTMPMw@mail.gmail.com>
References: <CAHA_kS1bzP5avxn8QdODBnFd2EFETTHgXyA4iLJsjj-vLTMPMw@mail.gmail.com>
Message-ID: <20130820031734.GB28406@faith.oztechninja.com>

The RTL2382U has an ADC onboard; The dongles don't use a seperate
ADC. The main other component is the tuner.

The RTL2382U uses a sigma-delta ADC, so it samples at a much higher
rate than it needs, but only at 1 bit. It then trades the high
sample rate for higher dynamic range. (Think reverse PWM, although
that is a huge oversimplification).  


http://www.maximintegrated.com/app-notes/index.mvp/id/1870

The crystal is to drive the clock of the RTL2832U. It's almost certainly
running a single 1 bit sample per clock.

If you were to get the samples at the 28.8Msps rate, they would be 1 bit 
samples, which you would still have to filter and downsample for most
uses.  I'm not aware of any way to get the samples out at that rate.

David

On Mon, Aug 19, 2013 at 11:44:51PM -0300, Lucas Ingles wrote:
> Hello to all,
> 
> Please, can someone help me to understand how RTL2832U samples signals?
> I know it has two ADCs, one for the I (in-phase) component and other ADC
> for the Q (quadrature) component.
> 
> In http://superkuh.com/rtlsdr.html the author states the signal is sampled
> initially at 28.8 Msps and then re sampled to present whatever sample rate
> is desired.
> 
> But
> http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=35&Level=4&Conn=3&ProdID=257
> says
> that 28.8MHz is the frequency of the crystal, not the ADC.
> 
> I am confused with that, can someone help me?
> If RTL2832U is able to sample at 28.8Msps, why don't use the maximum sample
> rate? Maybe USB limitations?
> 
> Also, all ADCs used in RTL-SDR dongles are inside RTL2832U? Or we have
> external ADCs?
> 
> Thanks very much in advance,
> Lucas Ingles



From davidb-sdr at rcpt.to  Tue Aug 20 04:24:21 2013
From: davidb-sdr at rcpt.to (David Basden)
Date: Tue, 20 Aug 2013 14:24:21 +1000
Subject: How RTL-SDR samples signals
In-Reply-To: <5212E6C8.1020103@earthlink.net>
References: <CAHA_kS1bzP5avxn8QdODBnFd2EFETTHgXyA4iLJsjj-vLTMPMw@mail.gmail.com>
	<20130820031734.GB28406@faith.oztechninja.com>
	<5212E6C8.1020103@earthlink.net>
Message-ID: <20130820042421.GC28406@faith.oztechninja.com>

Hmmm. You're right. My bad; I confused it with (I suspect) the E4000
VCO, and it really doesn't make sense given the wider channel bandwidth
of a DVB signal.

At 8 bits, 225 Msps isn't going to fit down USB2 though :(

On Mon, Aug 19, 2013 at 08:47:20PM -0700, jdow wrote:
> That doesn't necessarily square with "7-bit ADC for RF signals level
> measurement". It's unclear to me where it would get the signal with
> enough levels that a 7-bit ADC would get used. You'd have to decimate
> down to 225 Msps or so in order to get 7 bits of data.
> 
> {^_^}   Joanne/W6MKU
> 
> On 2013/08/19 20:17, David Basden wrote:
> >The RTL2382U has an ADC onboard; The dongles don't use a seperate
> >ADC. The main other component is the tuner.
> >
> >The RTL2382U uses a sigma-delta ADC, so it samples at a much higher
> >rate than it needs, but only at 1 bit. It then trades the high
> >sample rate for higher dynamic range. (Think reverse PWM, although
> >that is a huge oversimplification).
> >
> >
> >http://www.maximintegrated.com/app-notes/index.mvp/id/1870
> >
> >The crystal is to drive the clock of the RTL2832U. It's almost certainly
> >running a single 1 bit sample per clock.
> >
> >If you were to get the samples at the 28.8Msps rate, they would be 1 bit
> >samples, which you would still have to filter and downsample for most
> >uses.  I'm not aware of any way to get the samples out at that rate.
> >
> >David
> >
> >On Mon, Aug 19, 2013 at 11:44:51PM -0300, Lucas Ingles wrote:
> >>Hello to all,
> >>
> >>Please, can someone help me to understand how RTL2832U samples signals?
> >>I know it has two ADCs, one for the I (in-phase) component and other ADC
> >>for the Q (quadrature) component.
> >>
> >>In http://superkuh.com/rtlsdr.html the author states the signal is sampled
> >>initially at 28.8 Msps and then re sampled to present whatever sample rate
> >>is desired.
> >>
> >>But
> >>http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=35&Level=4&Conn=3&ProdID=257
> >>says
> >>that 28.8MHz is the frequency of the crystal, not the ADC.
> >>
> >>I am confused with that, can someone help me?
> >>If RTL2832U is able to sample at 28.8Msps, why don't use the maximum sample
> >>rate? Maybe USB limitations?
> >>
> >>Also, all ADCs used in RTL-SDR dongles are inside RTL2832U? Or we have
> >>external ADCs?
> >>
> >>Thanks very much in advance,
> >>Lucas Ingles
> >



From osmosdr at mkarcher.dialup.fu-berlin.de  Tue Aug 20 07:32:27 2013
From: osmosdr at mkarcher.dialup.fu-berlin.de (Michael Karcher)
Date: Tue, 20 Aug 2013 09:32:27 +0200
Subject: How RTL-SDR samples signals
In-Reply-To: <20130820042421.GC28406@faith.oztechninja.com>
References: <CAHA_kS1bzP5avxn8QdODBnFd2EFETTHgXyA4iLJsjj-vLTMPMw@mail.gmail.com>
	<20130820031734.GB28406@faith.oztechninja.com>
	<5212E6C8.1020103@earthlink.net>
	<20130820042421.GC28406@faith.oztechninja.com>
Message-ID: <1376983947.17180.55.camel@localhost>

Am Dienstag, den 20.08.2013, 14:24 +1000 schrieb David Basden:

As far as I understand it, sampling really happens at 28.8MHz with
probably 8 bits per channel. These ADCs are integrated in the RTL2832U
chip. After sampling, the samples are filtered using a symmetric FIR
filter (I reported how that filter is programmed around a year ago on
this list), then resampled to four times the user ADC. At that stage, a
second FIR anti-alias filter which seems ot be fixed (or running on
default coefficients all the time) kicks in before down-sampling to the
requested sample rate.

The 7-bit ADC quoted by jdow is also present on the chip, but it is a
low-bandwidth ADC. Some tuner chips, like the FC0012 (one of my dongles
has that chip) have a wide-bandwidth rectifier indicating the total RF
level at the input, but only an analog output but no digital provision
to read that level. The 7-bit ADC is used to measure the RF level to set
the RF gain for the tuner.

The 3.2MSps limit is definitely caused by the USB interface in the RTL
chips, actually, in my experience, already 2.88MHz is sometimes dropping
samples. It seems (from comments in the vendor-provided DVB-T driver)
like there might be a way to run that chip in USB isochronous mode
instead of bulk mode, but I have no idea whether that would require
strap modification, or just fiddling with some registers in the USB
interface section.

> On Mon, Aug 19, 2013 at 08:47:20PM -0700, jdow wrote:
> > That doesn't necessarily square with "7-bit ADC for RF signals level
> > measurement". It's unclear to me where it would get the signal with
> > enough levels that a 7-bit ADC would get used. You'd have to decimate
> > down to 225 Msps or so in order to get 7 bits of data.
> > 
> > {^_^}   Joanne/W6MKU

Regards,
  Michael Karcher





From 1cjcarpenter at att.net  Tue Aug 20 11:49:43 2013
From: 1cjcarpenter at att.net (Curt Carpenter)
Date: Tue, 20 Aug 2013 06:49:43 -0500
Subject: Is My RTL2838U + R820T Tuner working?
Message-ID: <521357D7.9060705@att.net>

Just to close the loop...

Thanks to Skip's link to rtl_fm here on the list,  I've finally managed 
to get my dongle working, and am happily listening to my local FM 
station on my computer now :-)

And now that I'm sure my hardware is working, I can start to explore the 
osmocom software seriously.   Thanks for the help!




From jared.clements at gmail.com  Tue Aug 20 13:22:04 2013
From: jared.clements at gmail.com (Jared Clements)
Date: Tue, 20 Aug 2013 07:22:04 -0600
Subject: Problems compiling rtl-sdr on debian
In-Reply-To: <20130819231049.4732.qmail@stuge.se>
References: <CAKwpmoKy-JiBbwDsUCWuqkMRh0L=w-SYy2o4gj9wF1PZNmMrbw@mail.gmail.com>
	<201308041743.56095.df8oe@gmx.de>
	<CAKwpmoJMMfB+SH75F828mkV=RpNBA4shzdWRLu1ZSOSy_zoWKg@mail.gmail.com>
	<CAKwpmoL07o85xYcxXa63B54nL3Fm6yf-mpanxnXTOtwzuEYRPQ@mail.gmail.com>
	<CAKwpmoKOef0e94gzd0q6eDwf1HsQBr967G8S-u_nkPZm71=otQ@mail.gmail.com>
	<CAKwpmoJ--Y3Rg43fOo44gvn=Ud6e9mozqX92KpzmaCZXF9+7eQ@mail.gmail.com>
	<20130805111841.11860.qmail@stuge.se>
	<CAKwpmoKj4a6Z7t+t5i=E20Jx7FF9Wtdq9Y_SxP2TpLdJKxgFyA@mail.gmail.com>
	<CAKwpmoKQcv4hFbSF_fM-ZVPbMZQ6B3-iOuKD8tOmA7B+aDzOaA@mail.gmail.com>
	<20130819231049.4732.qmail@stuge.se>
Message-ID: <CAPhnnGs0FQr2ACvY+WJAWBsk2sdFaf4KEun4Gbj21qAej7RZFQ@mail.gmail.com>

sigh, it all broke... command line tools still work, rtl_fm will allow
me to listen to fm stations, rtl_test shows no errors, but anything
else (gqrx, gnuradio) segfaults or just hangs.  Haven't recompiled
since late july, and will now downgrade from testing to stable and
re-attack everything... going to let debian work out the bugs in the
libusb transition before attempting testing again.

Jared

On Mon, Aug 19, 2013 at 5:10 PM, Peter Stuge <peter at stuge.se> wrote:
> lee jones wrote:
>> >>It would be interesting to see the output from a run that uses
>> >>libusb-1.0.9 or better yet the code from libusb.git
>>
>> I've still not tried this btw. If I remove libusb-1.0-0 it appears it
>> will break all manner of stuff x.x . Is there any sort of workaround
>> possible?
>
> Use the principle documented at http://libusb.org/wiki/debug
>
>
> //Peter
>



From alex_stani at yahoo.it  Tue Aug 20 14:46:54 2013
From: alex_stani at yahoo.it (Alessandro Staniscia)
Date: Tue, 20 Aug 2013 15:46:54 +0100 (BST)
Subject: Proposal: Java wrapping of .dll/.so
Message-ID: <1377010014.93596.YahooMailNeo@web171203.mail.ir2.yahoo.com>

Hi ml users,

I'm a newbie of this ml and this is my first message. So, just a little 
presentation of me: I'm a Software analyst and I work full time with 
java
 and some time in C++. I was a linux user on my beautiful but defunct 
linux laptop! Now (almost 15 days) I'm a linux user on windows laptop.
Into the company, java is a solution to write a Crossplatform service and software.
In
 my free time I have used various tools based of rtlsdr library, and I 
found very difficult to retrieve alternative of all? linux-based 
software! 
So, if I would write java program, does exist a java
 wrapping of rtlsdr library? In your opinion, building a wrapper of the library is a stupid or a good feature?
IMHO many software ( parser/plotter/networktool) are
 written in java and this is a opportunity for the library to retrieve this knowhow.
What do you think? 
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From john at johnmoe.com  Sat Aug 24 20:45:31 2013
From: john at johnmoe.com (John Moe)
Date: Sat, 24 Aug 2013 15:45:31 -0500
Subject: Debian Jessie and kernel 3.9.1
In-Reply-To: <CAHKdsmRS3oPJjvXx1zwAUkD_YwbtWzM7G=ZSBQD0sGZTER9=rw@mail.gmail.com>
References: <CAHKdsmRS3oPJjvXx1zwAUkD_YwbtWzM7G=ZSBQD0sGZTER9=rw@mail.gmail.com>
Message-ID: <CAGhGHviUJ3haRyWbN86-ctBmTBg2oGJ+Jizs+s=k+tMCf=3okQ@mail.gmail.com>

Increasing usbcore.usbfs_memory_mb or decreasing the number/size of the
buffers requested in rtlsdr_read_async fixes this for me.




On Mon, Aug 12, 2013 at 9:55 AM, Anton Komarov <anton.komarov at gmail.com>wrote:

> Tested several rtl dongles with linux 3.9.1 on Debian Jessie (testing)
> and got disappointing results
> 2 dongles simultaneously working ok
> if using 3 or more than 3rd dongle not working (1st and 2nd working ok)
>
> in Debian Wheezy i did manage to run 5 dongles simultaneously (kernel 3.2)
> i suppose  developers should pay attention to than fact.
> --
> public PGP key
> http://pastebin.com/dqZqgyVE
>
>
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From leif at sm5bsz.com  Sat Aug 24 23:20:26 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Sun, 25 Aug 2013 01:20:26 +0200
Subject: Debian Jessie and kernel 3.9.1
In-Reply-To: <CAHKdsmRS3oPJjvXx1zwAUkD_YwbtWzM7G=ZSBQD0sGZTER9=rw@mail.gmail.com>
References: <CAHKdsmRS3oPJjvXx1zwAUkD_YwbtWzM7G=ZSBQD0sGZTER9=rw@mail.gmail.com>
Message-ID: <20130825012026.ff573a12186367864f15ee71@sm5bsz.com>

Hello Anton,

It is not only your system. I tried Debian Jessie with
the 3.10-2-amd64 kernel.

I follow the same procedure that works rock stable in Wheezy:

Open 8 terminal windows. Start top in the 8th window.

Then start rtlsdr (I use Linrad) One dongle for each terminal
window. I have 7 dongles and they work all glitch-free in Wheezy
at 2.4 MHz with a total CPU load of about 40% on a 8 core machine
with 4667 bogomips.

If I have only a single dongle connected to the computer it works
under Jessie, but if I have two or more the system crasches. 
If I open terminals first when needed I can run three dongles, 
at least some times, but with all the terminal windows open 
the system crasches already when I try to get the first dongle 
running.

I have seen 100.1% CPU load from udevd as well as kworker/4:1
and other kworkers. There is no way out except the reset switch.

The Debian bug report system is too complicated so I am not able
to file a report to the developers. They assume I have configured 
exim4 or remember the details of my mail accounts....

It seems to be a severe bug so I guess they get reports from
others.

/ Leif


On Mon, 12 Aug 2013 18:55:22 +0400
Anton Komarov <anton.komarov at gmail.com> wrote:

> Tested several rtl dongles with linux 3.9.1 on Debian Jessie (testing)
> and got disappointing results
> 2 dongles simultaneously working ok
> if using 3 or more than 3rd dongle not working (1st and 2nd working ok)
> 
> in Debian Wheezy i did manage to run 5 dongles simultaneously (kernel 3.2)
> i suppose  developers should pay attention to than fact.
> --
> public PGP key
> http://pastebin.com/dqZqgyVE



From putaoshu at gmail.com  Sun Aug 25 13:13:50 2013
From: putaoshu at gmail.com (Jiao Xianjun)
Date: Sun, 25 Aug 2013 21:13:50 +0800
Subject: How to get IQ samples from multiple rtl-sdr dongles in a synchronized
	manner?
Message-ID: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>

Hi,

I want to use multiple rtl-sdr dongles to do some multi-antenna experiments.

Is it possible to read IQ samples from multiple rtl-sdr dongles in a
synchronized manner?

I already have a glance at dump1090 codes, which is a project using rtl-sdr
to decode aircraft broadcasting ADS-B messages in 1090MHz.

Seems that I should use rtlsdr_read_async() instead of rtlsdr_read_sync(),
because that if rtlsdr_read_sync() is used, I have to call it multiple
times sequentially. That looks not synchronized.

But rtlsdr_read_async() function only accept one rtl-sdr device as input
parameter, and it will be blocked after it is called. So seems that it also
can't be used for my purpose directly.

Also welcome any opinion on how to improve rtl-sdr lib/driver to support
this feature.

Thank you.

BR

Jiao Xianjun
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From thierry.leconte at laposte.net  Sun Aug 25 13:49:37 2013
From: thierry.leconte at laposte.net (Thierry Leconte)
Date: Sun, 25 Aug 2013 15:49:37 +0200
Subject: How to get IQ samples from multiple rtl-sdr dongles in a
	synchronized manner?
In-Reply-To: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>
References: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>
Message-ID: <521A0B71.2000100@laposte.net>

Le 25/08/2013 15:13, Jiao Xianjun a ?crit :
> Hi,
>
> I want to use multiple rtl-sdr dongles to do some multi-antenna 
> experiments.
>
> Is it possible to read IQ samples from multiple rtl-sdr dongles in a 
> synchronized manner?
>
Each dongle have its own clock, so it will never be synchronized at the 
sample level.




From putaoshu at gmail.com  Sun Aug 25 14:13:36 2013
From: putaoshu at gmail.com (Jiao Xianjun)
Date: Sun, 25 Aug 2013 22:13:36 +0800
Subject: How to get IQ samples from multiple rtl-sdr dongles in a
	synchronized manner?
In-Reply-To: <521A0B71.2000100@laposte.net>
References: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>
	<521A0B71.2000100@laposte.net>
Message-ID: <CABs6FUq1tRWk9GAtOJxQ9ZSdoc6qsgyShRFau+YdQhSmTR+jFg@mail.gmail.com>

basically you are right.
But there is signal processing algorithm to track two dongles
sampling/oscillator error separately and compensate them separately. Thus
we can get them synchronized finally after signal processing algorithm.

What I need actually is that how to get two streams of sample from two
dongles.

Actually I notice that in dump1090 it put rtlsdr_read_async in a new
created background thread, then there is a possibility that I create two
thread to operate two dongles. But in this method, there should be some
mechanisms to synchronize two threads. It is complicated.

Anyone has simpler solution?

Thank you.



On Sun, Aug 25, 2013 at 9:49 PM, Thierry Leconte <
thierry.leconte at laposte.net> wrote:

> Le 25/08/2013 15:13, Jiao Xianjun a ?crit :
>
>  Hi,
>>
>> I want to use multiple rtl-sdr dongles to do some multi-antenna
>> experiments.
>>
>> Is it possible to read IQ samples from multiple rtl-sdr dongles in a
>> synchronized manner?
>>
>>  Each dongle have its own clock, so it will never be synchronized at the
> sample level.
>
>
>
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From sylvain.azarian at gmail.com  Sun Aug 25 15:30:34 2013
From: sylvain.azarian at gmail.com (Sylvain AZARIAN)
Date: Sun, 25 Aug 2013 17:30:34 +0200
Subject: How to get IQ samples from multiple rtl-sdr dongles in a
	synchronized manner?
In-Reply-To: <CABs6FUq1tRWk9GAtOJxQ9ZSdoc6qsgyShRFau+YdQhSmTR+jFg@mail.gmail.com>
References: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>
	<521A0B71.2000100@laposte.net>
	<CABs6FUq1tRWk9GAtOJxQ9ZSdoc6qsgyShRFau+YdQhSmTR+jFg@mail.gmail.com>
Message-ID: <CAHZVKw18XUjuUpKqfP24COH5P4uoB+fGU0TyJBnTrS_QJDvXfg@mail.gmail.com>

Another issue you'll have is to start both dongles simultaneously...
with the sampling rate you'll have on the dongles this becomes quite tricky
: you get blocks of samples from both dongles but you have no idea of how
many samples they are shifted in time. One way to solve this is to search
for cross correlation between channels, but this is not very easy in
realtime. This can be done by post-processing offline.
I thaught of this a while ago, using a pin diode or something equivalent to
shortcut both inputs to ground to find an easy way to have the synchro
between channels but did not try it yet

sylvain


2013/8/25 Jiao Xianjun <putaoshu at gmail.com>

> basically you are right.
> But there is signal processing algorithm to track two dongles
> sampling/oscillator error separately and compensate them separately. Thus
> we can get them synchronized finally after signal processing algorithm.
>
> What I need actually is that how to get two streams of sample from two
> dongles.
>
> Actually I notice that in dump1090 it put rtlsdr_read_async in a new
> created background thread, then there is a possibility that I create two
> thread to operate two dongles. But in this method, there should be some
> mechanisms to synchronize two threads. It is complicated.
>
> Anyone has simpler solution?
>
> Thank you.
>
>
>
> On Sun, Aug 25, 2013 at 9:49 PM, Thierry Leconte <
> thierry.leconte at laposte.net> wrote:
>
>> Le 25/08/2013 15:13, Jiao Xianjun a ?crit :
>>
>>  Hi,
>>>
>>> I want to use multiple rtl-sdr dongles to do some multi-antenna
>>> experiments.
>>>
>>> Is it possible to read IQ samples from multiple rtl-sdr dongles in a
>>> synchronized manner?
>>>
>>>  Each dongle have its own clock, so it will never be synchronized at the
>> sample level.
>>
>>
>>
>
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From skip.tavakkolian at gmail.com  Sun Aug 25 16:11:37 2013
From: skip.tavakkolian at gmail.com (Skip Tavakkolian)
Date: Sun, 25 Aug 2013 09:11:37 -0700
Subject: How to get IQ samples from multiple rtl-sdr dongles in a
	synchronized manner?
In-Reply-To: <CABs6FUq1tRWk9GAtOJxQ9ZSdoc6qsgyShRFau+YdQhSmTR+jFg@mail.gmail.com>
References: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>
	<521A0B71.2000100@laposte.net>
	<CABs6FUq1tRWk9GAtOJxQ9ZSdoc6qsgyShRFau+YdQhSmTR+jFg@mail.gmail.com>
Message-ID: <CAJSxfm+ydaMa_QejmEcX2_Ox4JFcHaNmkz+3KGj51st-XAQi-w@mail.gmail.com>

if you are trying to process ADS-B from two different dongles, running two
dump1090's isn't a problem. i routinely run dump1090 and rtl_acars using
two dongles on the same machine simultaneously. when running two dump1090
process you must provide the device id for each and make sure both aren't
running their web servers on the same port.

a more useful setup is to have multiple receivers running on cheap servers
(e.g. raspberry pi) at different locations and then collecting and
correlating the data.  having receivers at different locations should yield
a larger coverage area.


On Sun, Aug 25, 2013 at 7:13 AM, Jiao Xianjun <putaoshu at gmail.com> wrote:

> basically you are right.
> But there is signal processing algorithm to track two dongles
> sampling/oscillator error separately and compensate them separately. Thus
> we can get them synchronized finally after signal processing algorithm.
>
> What I need actually is that how to get two streams of sample from two
> dongles.
>
> Actually I notice that in dump1090 it put rtlsdr_read_async in a new
> created background thread, then there is a possibility that I create two
> thread to operate two dongles. But in this method, there should be some
> mechanisms to synchronize two threads. It is complicated.
>
> Anyone has simpler solution?
>
> Thank you.
>
>
>
> On Sun, Aug 25, 2013 at 9:49 PM, Thierry Leconte <
> thierry.leconte at laposte.net> wrote:
>
>> Le 25/08/2013 15:13, Jiao Xianjun a ?crit :
>>
>>  Hi,
>>>
>>> I want to use multiple rtl-sdr dongles to do some multi-antenna
>>> experiments.
>>>
>>> Is it possible to read IQ samples from multiple rtl-sdr dongles in a
>>> synchronized manner?
>>>
>>>  Each dongle have its own clock, so it will never be synchronized at the
>> sample level.
>>
>>
>>
>
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From putaoshu at gmail.com  Mon Aug 26 02:49:58 2013
From: putaoshu at gmail.com (Jiao Xianjun)
Date: Mon, 26 Aug 2013 10:49:58 +0800
Subject: How to get IQ samples from multiple rtl-sdr dongles in a
	synchronized manner?
In-Reply-To: <CAHZVKw18XUjuUpKqfP24COH5P4uoB+fGU0TyJBnTrS_QJDvXfg@mail.gmail.com>
References: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>
	<521A0B71.2000100@laposte.net>
	<CABs6FUq1tRWk9GAtOJxQ9ZSdoc6qsgyShRFau+YdQhSmTR+jFg@mail.gmail.com>
	<CAHZVKw18XUjuUpKqfP24COH5P4uoB+fGU0TyJBnTrS_QJDvXfg@mail.gmail.com>
Message-ID: <CABs6FUrxh61R3fBX3RMuW4t4EYsiuLyb7qe7CaBNtedkpUoEtA@mail.gmail.com>

computer has become more powerful than our imagination. According to my
experiences, order of Msps correlation operation can be done in real time
by using state of art computer.
Instead of cross correlation, we can also transmit a training sequence (for
example spread code, m sequence, barker sequence, M sequence, ZC sequence,
etc.) to do synchronization and sampling/frequency correlation.


On Sun, Aug 25, 2013 at 11:30 PM, Sylvain AZARIAN <sylvain.azarian at gmail.com
> wrote:

> Another issue you'll have is to start both dongles simultaneously...
> with the sampling rate you'll have on the dongles this becomes quite
> tricky : you get blocks of samples from both dongles but you have no idea
> of how many samples they are shifted in time. One way to solve this is to
> search for cross correlation between channels, but this is not very easy in
> realtime. This can be done by post-processing offline.
> I thaught of this a while ago, using a pin diode or something equivalent
> to shortcut both inputs to ground to find an easy way to have the synchro
> between channels but did not try it yet
>
> sylvain
>
>
> 2013/8/25 Jiao Xianjun <putaoshu at gmail.com>
>
>> basically you are right.
>> But there is signal processing algorithm to track two dongles
>> sampling/oscillator error separately and compensate them separately. Thus
>> we can get them synchronized finally after signal processing algorithm.
>>
>> What I need actually is that how to get two streams of sample from two
>> dongles.
>>
>> Actually I notice that in dump1090 it put rtlsdr_read_async in a new
>> created background thread, then there is a possibility that I create two
>> thread to operate two dongles. But in this method, there should be some
>> mechanisms to synchronize two threads. It is complicated.
>>
>> Anyone has simpler solution?
>>
>> Thank you.
>>
>>
>>
>> On Sun, Aug 25, 2013 at 9:49 PM, Thierry Leconte <
>> thierry.leconte at laposte.net> wrote:
>>
>>> Le 25/08/2013 15:13, Jiao Xianjun a ?crit :
>>>
>>>  Hi,
>>>>
>>>> I want to use multiple rtl-sdr dongles to do some multi-antenna
>>>> experiments.
>>>>
>>>> Is it possible to read IQ samples from multiple rtl-sdr dongles in a
>>>> synchronized manner?
>>>>
>>>>  Each dongle have its own clock, so it will never be synchronized at
>>> the sample level.
>>>
>>>
>>>
>>
>
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From putaoshu at gmail.com  Mon Aug 26 02:56:32 2013
From: putaoshu at gmail.com (Jiao Xianjun)
Date: Mon, 26 Aug 2013 10:56:32 +0800
Subject: How to get IQ samples from multiple rtl-sdr dongles in a
	synchronized manner?
In-Reply-To: <CAJSxfm+ydaMa_QejmEcX2_Ox4JFcHaNmkz+3KGj51st-XAQi-w@mail.gmail.com>
References: <CABs6FUqY9D8-+aiTYOYGfRpgKdeK=UboTzr19i1o+j=m7b9KUg@mail.gmail.com>
	<521A0B71.2000100@laposte.net>
	<CABs6FUq1tRWk9GAtOJxQ9ZSdoc6qsgyShRFau+YdQhSmTR+jFg@mail.gmail.com>
	<CAJSxfm+ydaMa_QejmEcX2_Ox4JFcHaNmkz+3KGj51st-XAQi-w@mail.gmail.com>
Message-ID: <CABs6FUoP-Nj1P3Wpc_FNEY0fuQwBunyqsHLmcz_YVWNKQmm1Jg@mail.gmail.com>

Hi,

Yes, you are right. The thought is kind of message combination or
information fusion, diversity receiving. In this situation, large distance
spaced antennas/dongles are required to get enough diversity.
But in some application, such as beam forming, direction finding, we want
to have antennas/dongles located in a strict relation ship, such as
lambda/2 spaced antenna array. In this case we want to detect carrier
phases of each channels.



On Mon, Aug 26, 2013 at 12:11 AM, Skip Tavakkolian <
skip.tavakkolian at gmail.com> wrote:

> if you are trying to process ADS-B from two different dongles, running two
> dump1090's isn't a problem. i routinely run dump1090 and rtl_acars using
> two dongles on the same machine simultaneously. when running two dump1090
> process you must provide the device id for each and make sure both aren't
> running their web servers on the same port.
>
> a more useful setup is to have multiple receivers running on cheap servers
> (e.g. raspberry pi) at different locations and then collecting and
> correlating the data.  having receivers at different locations should yield
> a larger coverage area.
>
>
> On Sun, Aug 25, 2013 at 7:13 AM, Jiao Xianjun <putaoshu at gmail.com> wrote:
>
>> basically you are right.
>> But there is signal processing algorithm to track two dongles
>> sampling/oscillator error separately and compensate them separately. Thus
>> we can get them synchronized finally after signal processing algorithm.
>>
>> What I need actually is that how to get two streams of sample from two
>> dongles.
>>
>> Actually I notice that in dump1090 it put rtlsdr_read_async in a new
>> created background thread, then there is a possibility that I create two
>> thread to operate two dongles. But in this method, there should be some
>> mechanisms to synchronize two threads. It is complicated.
>>
>> Anyone has simpler solution?
>>
>> Thank you.
>>
>>
>>
>> On Sun, Aug 25, 2013 at 9:49 PM, Thierry Leconte <
>> thierry.leconte at laposte.net> wrote:
>>
>>> Le 25/08/2013 15:13, Jiao Xianjun a ?crit :
>>>
>>>  Hi,
>>>>
>>>> I want to use multiple rtl-sdr dongles to do some multi-antenna
>>>> experiments.
>>>>
>>>> Is it possible to read IQ samples from multiple rtl-sdr dongles in a
>>>> synchronized manner?
>>>>
>>>>  Each dongle have its own clock, so it will never be synchronized at
>>> the sample level.
>>>
>>>
>>>
>>
>
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From keenerd at gmail.com  Wed Aug 28 11:55:29 2013
From: keenerd at gmail.com (keenerd)
Date: Wed, 28 Aug 2013 07:55:29 -0400
Subject: rtl_fm, rtl_power, mingw, r820t
Message-ID: <CAAKTTKPZ_uU2SxaXgVAf7EmzBD4grWoFgYh8zAtE_1d2dU040g@mail.gmail.com>

Hey all.

I've been shouting it all over /r/rtlsdr and ##rtlsdr, but just for
you fine folks that are only on the ML, here[1] is what I've been up
to the past week:

Overhauled scanning in rtl_fm.  This fixed a number of issues, where
either scanning did not work at all and some brokenness on OpenBSD.
It also meant giving up on the async API entirely.

Released a whole new application, rtl_power.  This is something I'd
had bouncing around on my hard drive for many months, half-unwritten
due to over-complexity.  It'll generate CSV files of arbitrarily
slow/wide/detailed FFTs.  Also a little visualization script[2] that
won't choke when you give it 50,000 columns of data.

In the process of testing rtl_power, two more things came up.  First
was windows builds.  I've got a half-finished mingw32 build script[3]
that'll let me produce windows binaries[4] on a linux host.  These
have been confirmed to actually run and probably work.  Only W32 for
now, but just because I was too lazy to build the W64 toolchain.

Second was the discovery[5] that scanning had gotten a whole lot
slower since my original experiments with rtl_fm.  85mS to retune is
unacceptably slow.  Since the r820t driver is the slowest, I started
looking into figuring out what is going on.  Still figuring that out
but I have done basic cleanups to the code (removing redundancy,
particularly around register writes) and the driver is 15% shorter
with no modifications to code behavior.

I would not mind talking to Steve or one of the other devs on IRC
about some of the more ambiguous aspects of the driver.  (Like, why
some reg writes are backed up to R828_Arry[] and others aren't.  And
is that array thread safe at all?  If not I'll have to do some very
large changes to support multiple dongles in rtl_power.)

I would really like to get these changes merged, particularly the
rtl_fm stuff because the version in the official repo is rather
bit-rotten.

-Kyle
http://kmkeen.com

[1] https://github.com/keenerd/rtl-sdr
[2] http://www.reddit.com/r/RTLSDR/comments/1ktzwi/
[3] http://kmkeen.com/tmp/mingw32.sh.txt
[4] http://kmkeen.com/tmp/rtl-sdr-mingw32-2013-08-28.zip
[5] http://www.reddit.com/r/RTLSDR/comments/1l2vlx/



From leif at sm5bsz.com  Wed Aug 28 15:50:29 2013
From: leif at sm5bsz.com (Leif Asbrink)
Date: Wed, 28 Aug 2013 17:50:29 +0200
Subject: Obsolete: INCLUDES
In-Reply-To: <CACR-see9SZA=H0N_BvN9p5qG5beqaW0oKb7z=ZYgJFEzKaBkkQ@mail.gmail.com>
References: <ku513p+kvj9@eGroups.com>
	<20130810232956.777b4c410ba63df8efa21ec1@sm5bsz.com>
	<003501ce9663$0d096010$271c2030$@me.uk>
	<20130811224851.e0f1ca17a9337b6c99aec6ba@sm5bsz.com>
	<CACR-see9SZA=H0N_BvN9p5qG5beqaW0oKb7z=ZYgJFEzKaBkkQ@mail.gmail.com>
Message-ID: <20130828175029.1814c483e286b01346578a3d@sm5bsz.com>

Hi All,

An attempt to install rtlsdr under Mageia 3 (32 bit) failed
with a message saying INCLUDES is obsolete and should be
replaced by AM_CPPFLAGS

That means that line 4 in rtl-sdr/Makefile.am and 
rtl-sdr/src/Makefile.am should be changed.

I have verified that this is ok for Ubuntu 9.04 which
is the oldest version on my multiboot system.

Regards

Leif




From john at tonebridge.com  Wed Aug 28 22:16:56 2013
From: john at tonebridge.com (John)
Date: Wed, 28 Aug 2013 17:16:56 -0500
Subject: rtl_fm, rtl_power, mingw, r820t
In-Reply-To: <CAAKTTKPZ_uU2SxaXgVAf7EmzBD4grWoFgYh8zAtE_1d2dU040g@mail.gmail.com>
References: <CAAKTTKPZ_uU2SxaXgVAf7EmzBD4grWoFgYh8zAtE_1d2dU040g@mail.gmail.com>
Message-ID: <521E76D8.3040407@tonebridge.com>

Great work and thanks for posting this here!

I am looking forward to trying the new code.  I have been unable to get 
scanning to work and existing problems you indicate may be the reason why.

John




From john at tonebridge.com  Fri Aug 30 15:04:15 2013
From: john at tonebridge.com (John)
Date: Fri, 30 Aug 2013 10:04:15 -0500
Subject: Calibration / PPM
Message-ID: <5220B46F.2090004@tonebridge.com>

I am trying to get my head around calibration of my RTL dongle.  I used 
gqrx with a known frequency (467.6375Mhz).  Based on this, the dongle 
needs offset of -16Khz.  In gqrx, this offset can be entered directly in 
the user interface.

With rtl_test -p, the PPM number varies.   I have gotten positive and 
negative numbers.

When using the RTL block in gnuradio companion, I need to enter PPM.  I 
have seen various formulas to calculate PPM from frequencies but for me 
they do not yield sane results.   I could be just misusing these formulas.

Any assistance would be appreciated.

Thanks,

John



From john at tonebridge.com  Fri Aug 30 15:13:27 2013
From: john at tonebridge.com (John)
Date: Fri, 30 Aug 2013 10:13:27 -0500
Subject: Calibration / PPM
In-Reply-To: <5220B46F.2090004@tonebridge.com>
References: <5220B46F.2090004@tonebridge.com>
Message-ID: <5220B697.5040109@tonebridge.com>

This request can be ignored for now.

I missed in gqrx where PPM can be selected.   I was using LNB LO as 
correction factor.

With this information I should now be able to determine PPM directly.

Thanks,

John