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
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!
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…
> >>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
> >
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…
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
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
This is with a version of rtl-sdr I got by git last night and OpenBSD 5.2 (current release). 5.2 has some pthreads fixing so I waited until I bought another computer and loaded it. Are the crashes related to threads? I don't know, but possibly. It didn't work with OpenBSD 5.0 either.
rtl_fm crashes and uses threads
rtl_adsb crashes and uses threads
rtl_tcp doesn't crash, uses threads, actually stops on ctrl-c
rtl_test doesn't crash, doesn't use threads, won't stop
rtl_eeprom doesn't crash, doesn't use threads, ends normally
I'm not real practiced using gdb but I tried looking at a couple of core files, here's a run of rtl_fm:
rtl_fm -f 162550000 -N - | play -t raw -r 24k -e signed-integer -b 16 -c 1
-V1 -
-: (raw)
Encoding: Signed PCM
Channels: 1 @ 16-bit
Samplerate: 24000Hz
Replaygain: off
Duration: unknown
In:0.00% 00:00:00.00 [00:00:00.00] Out:0 [ | ] Clip:0
Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000013
Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle
Found Rafael Micro R820T tuner
Oversampling input by: 42x.
Oversampling output by: 1x.
Buffer size: 8.13ms
Tuned to 162802000 Hz.
Sampling at 1008000 Hz.
Output at 24000 Hz.
Exact sample rate is: 1008000.009613 Hz
Tuner gain set to automatic.
In:0.00% 00:00:00.00 [00:00:00.00] Out:0 [ | ] Clip:0
Done.
Abort (core dumped)
d530# gdb -c rtl_fm.core /usr/local/bin/rtl_fm
GNU gdb 6.3
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-unknown-openbsd5.2"...
Core was generated by `rtl_fm'.
Program terminated with signal 6, Aborted.
Reading symbols from /usr/lib/libpthread.so.16.0...done.
Loaded symbols for /usr/lib/libpthread.so.16.0
Reading symbols from /usr/lib/libm.so.7.0...done.
Loaded symbols for /usr/lib/libm.so.7.0
Reading symbols from /usr/local/lib/librtlsdr.so.0.0...done.
Loaded symbols for /usr/local/lib/librtlsdr.so.0.0
Reading symbols from /usr/local/lib/libusb-1.0.so.1.0...done.
Loaded symbols for /usr/local/lib/libusb-1.0.so.1.0
Symbols already loaded for /usr/lib/libpthread.so.16.0
Reading symbols from /usr/lib/libc.so.65.0...done.
Loaded symbols for /usr/lib/libc.so.65.0
Loaded symbols for /usr/libexec/ld.so
#0 0x0abbd98d in kill () from /usr/lib/libc.so.65.0
(gdb) bt
#0 0x0abbd98d in kill () from /usr/lib/libc.so.65.0
#1 0x0ac29545 in abort () at /usr/src/lib/libc/stdlib/abort.c:68
#2 0x005e9298 in pthread_mutex_unlock (mutexp=0x3c003d8c)
at /usr/src/lib/librthread/rthread_sync.c:218
#3 0x1c00266e in full_demod (fm=0xcfa2de5c)
at /usr/src/misc/osmocom/2013-04-15/rtl-sdr/src/rtl_fm.c:583
#4 0x1c0028ff in demod_thread_fn (arg=0xcfa2de5c)
at /usr/src/misc/osmocom/2013-04-15/rtl-sdr/src/rtl_fm.c:641
#5 0x005ebc2e in _rthread_start (v=0x84da4c00)
at /usr/src/lib/librthread/rthread.c:111
#6 0x0aba62e9 in __tfork_thread () from /usr/lib/libc.so.65.0
The backtrace (bt) shows that it dies trying to do a mutex_unlock (I think). rtl_tcp also does a mutex_unlock and it doesn't crash. I'm probably reading it wrong for all I know. I don't know what's causing the signal 6 either.
I'd also like to get the -lrt of of the cmake files. OpenBSD doesn't use or have lrt, it works without. I can edit it out and compile, but every time I run cmake again, I have to edit the files again.
Alan
-----
Radio Astronomy - the ultimate DX
---------- Forwarded message ----------
From: *Andrew Mount*
Date: Friday, August 9, 2013
Subject: Need a starting point to learn RTL-SDR
To: Andrew Back <andrew(a)carrierdetect.com>, "
osmocom-sdr-request(a)lists.osmocom.org" <
osmocom-sdr-request(a)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(a)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
>
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
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
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
