[SOLVED] How easy/hard is SDR on Linux?

273 · 08-22-2015, 01:34 PM

I am considering buying a cheap USB SDR, probably one of these (well, OK, I'm almost certainly purchasing one in the next couple of weeks unless I find it would be a waste of money):
http://www.amazon.co.uk/Receiver-RTL...7&keywords=sdr
I like the idea of listening to aircraft control (I live fairly near an airport) and exploring anything else I may discover. I have been googling around and, while it seems there are lots of SDR packages in Debian, most tutorials and the like seems to suggest that one needs to clone GIT repositories and compile things to get the devices working.
So, how easy is it to get SDR working under Linux and do the tools need a lot of knowledge to use?
I'm not too worried about compiling from GIT and the like, but I would prefer just apt-get for simplicities sake so uninstalling is easier and the like. I also don't mind reading a lot of material about SDR and radio fundamentals but it would be good to know some decent starter reading.
Any SDR people out there have any advice?

fatmac · 08-23-2015, 06:54 AM

Basically it looks like you may have trouble getting drivers for some, that is why they are talking about the git repos.

If you are happy with compiling, & someone is working on a driver for your device, it should work out OK.

derive · 08-31-2015, 08:38 PM

I have an sdr setup on debian. It was a little bit hard for me to get it work with pulseaudio, but finally it works.
But you need an sdr with a recommended tuner chip. As I remember the ubuntu packages works out of the box (tried that out before starting to compile, etc.) with a good hardware (tuner chip).
I tried two nameless chinese usb tv tuner, both was working, but one of them is limited in frequency range ( caused by the tuner ), so you should choose that correctly, that's the secret

http://www.instructables.com/id/rtl-sdr-on-Ubuntu/
http://gqrx.dk/
http://packages.ubuntu.com/trusty/libs/rtl-sdr

273 · 09-04-2015, 12:54 PM

Well, I ordered the card linked to not long after posting and it arrived last night. I tried to install gnuradio this morning but the package seems to be broken in Sid -- unresolved dependencies. Is there an alternative?
I'll try to play with Windows to confrm the device works but, as I understand it, I can't use a VirtualBox VM under my current installs because the USB bandwidth (or latency?) is too bad?
I'll try it on my desktop too, also running Sid, in case it's just a package conflict -- doesn't seem like it though.

derive · 09-04-2015, 01:26 PM

Check an older package from the http://ftp.fsn.hu/debian/pool/main/g/gnuradio/ and install it with dpkg -i, after that apt-get -f install, if it can resolv the dependencies... I can check my version on monday...

273 · 09-04-2015, 01:32 PM

Quote:

Originally Posted by derive

Check an older package from the http://ftp.fsn.hu/debian/pool/main/g/gnuradio/ and install it with dpkg -i, after that apt-get -f install, if it can resolv the dependencies... I can check my version on monday...

Thanks, heading home now [eventually] so I might try that later tonight.
As I mentioned, I am not against compiling but it would make it a lot easier if I could use packages on all my machines.
Have you listened to Air Traffic Control at all yourself?
I may actually use the device as a digital TV stick if it works and just play too, of course.

273 · 09-04-2015, 03:09 PM

IT seems that I can now install gnuradio and gqrx-sdr on both machines I've tried it on. I think I had problems with repositories earlier.
I'll report back upon my failures.

273 · 09-04-2015, 03:43 PM

I have gnuradio installed and have started it and it seems to detect the device. However, when I start playback I can't seem to find a channel which provides me with anything that sound like voice. Is there any way I can verify that this is working at all will it, for example, tune into my local FM radio broadcaster in the UK and, if so, what are the settings? I dialled in what I thought was the frequency of the local FM station but I didn't even get a change in the static using any of hte FM modes.

tredegar · 09-06-2015, 07:10 AM

If you are going to listen to ATC, you might want to know where the planes are...

Slightly off-topic, but I have dump1090 running on my Raspian Pi with a RTL2838 DVB-T dongle, with a simple bent-wire aerial.

This tracks all the planes over SE England that are equipped with ADS-B (ie most of them).

I can watch air traffic in real time on my laptop's browser, and upload my air traffic data to
http://www.flightradar24.com/51.56,-0.27/9

This project was dirt cheap, and way too much fun.

273 · 09-06-2015, 07:25 AM

Quote:

Originally Posted by tredegar

If you are going to listen to ATC, you might want to know where the planes are...

Yeah, I had looked at that but for the time being I'm just trying to work out whether my unit's faulty or not. I'm fairly close to an airport and I've found the various ATC frequencies but I'm getting nothing on any of them. The device is definitely detected as gnuradio produces static when it's plugged in but doesn't do anything when it's not. The provided aerial is tiny but I would expect to, at least, hear something when tuned to the local radio station but I can't get anything at all. There's, perhaps, something monumentally obvious I'm missing here?

tredegar · 09-06-2015, 08:19 AM

You might need to check which modules are being loaded when it is plugged in. Maybe blacklist them, and try again.

I forget the details, but when I played with gnuradio, I had trouble if the kernel decided I had plugged in a DVB-T stick and therefore assumed I wanted to watch TV, when I just wanted to play with gnuradio.

273 · 09-06-2015, 08:23 AM

How do I go about finding out what is loaded? I tried dmesg but just see:

Code:

[ 8339.670413] usb 3-2: new high-speed USB device number 2 using xhci_hcd
[ 8339.866942] usb 3-2: New USB device found, idVendor=0bda, idProduct=2838
[ 8339.866954] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 8339.866959] usb 3-2: Product: RTL2838UHIDIR
[ 8339.866963] usb 3-2: Manufacturer: Realtek
[ 8339.866967] usb 3-2: SerialNumber: 00000001

tredegar · 09-06-2015, 09:10 AM

Code:

lsmod

Will list all the modules that are loaded.
You could run lsmod > before on a freshly booted machine, then plug in the RTL2838 and run lsusb > after, then compare before with after.

273 · 09-06-2015, 09:28 AM

Running "lsmod | wc -l" before and after insertion returns the same value of 121 and I can't see anything in the listing that suggests it's for the device. It's seen with lsusb though (as "Bus 003 Device 002: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T") and, as mentioned, when I fire up gnuradio it does seem to see the device I just don't get anything that sounds like a broadcast.
I did fire up an SDR program under Windows also and couldn't find anything with that either. So, I think that either the device is faulty or I'm doing something wrong here. I'm not sure I can be bothered with the returns process but if I can confirm whether or not the device is faulty I'll know whether to buy another or not.

Edit: Sorry it's not gnuradio I'm using, as such, it's this:
https://packages.debian.org/wheezy-backports/gqrx-sdr

tredegar · 09-06-2015, 09:40 AM

If it doesn't work with linux or windows, think you are correct: The device is faulty.
I know the supplied aerial is small and cheap, so maybe try a different aerial if you can.