R-Pi and DVB-T dongle for SDR

[W9RAN]

I'd like to hear from other uses who are using their Pi to run rtl_tcp to serve I/Q packets from cheap DVB-T dongles as part of an SDR implementation. I'm having excellent success on wired ethernet, where 1.024 megasamples/sec runs 20% CPU utilization and 2.048 ms/s takes it up to about 45%. I run ssh to control the server from the PC that runs the DSP app (typically SDR#).

It took a few hours of frustration to determine that rtl_tcp cannot run while Xorg/XLDE is running. I'd like to understand why this is - does X preempt the ethernet datastream, or is it something else? The rtl server runs flawlessly from CLI but will not even start if the GUI is running. I have Wireshark captures of all the above if anyone would like to see them.

This setup makes it possible to locate a DVB-T dongle anywhere - near the antenna, for example - and serve packets via ethernet rather than suffering the length limitations of USB. And it's been a great learning opportunity for this linux noob

73, Bob W9RAN

[tony1tf]

Hi Bob

I'm trying to set up my RPi for a FunCube Dongle, but struggling to find the correct libraries etc. So have you got a list of the commands you used to set up for the rtl-tcp server?

Tony

[ferrymanr]

I wonder how far anyone has got with the funcube on the R-Pi. I have managed to get various amateur applications that use a soundcard to work properly but struggled at first. The latest firmware has made considerable improvements and I am getting reliable results with applicationbs that push simultaneous use of the USB and network quite hard. This has spurred me on to think of using a funcube dongle and R-Pi for monitoring 23cm beacons instead of using my current setup of transverter, FT-817 and laptop. I did have a play with a borrowed FCD on a PC some time ago but that was a much faster machine than the R-Pi and used Windows based software.
Dick G4BBH

[Ioan]

Hi all!,

I can confirm that Rpi is working with rtl-tcp. My setup on Rpi is the latest Rasbian with turbo mode on (1GHz), ThightVNC server on, SSH on, LXDE off, Apache2 off. On the PC side I run SDR# with a maximum sample rate of 1 000 000. More than 1Msps is not working. My dongle is a NewSky E4000/RTL2838. This setup works on my local LAN I didn't tried yet from outside my lan. I have noticed that Apache server prevented the rtl-tcp streaming even at low sampling rate of 25000sps so I have turned it off.

On the PC side also I run SSH into RPi to see what is happening there. Sometimes I run also VNC in just to bother the RPi a little bit more... Anyhow the processor is running low, less than 20%.

Overall RPi/RTL SDR dongle/rtl_tcp is a wonderfull mix.

73! Ioan/YO4 2783....

P.S. Right now I am running VLC player above all this setup streaming internet radio into my audio system. RPi at 75% processor load. Me listening the 2 meter band...