rtl_tcp OrangePi .pc to Ubuntu GQRX. RTLSDR Dongle over TCP Ethernet /Wifi.

Seasalt · April 6, 2016

For any one interested in software defined radio the OrangePi.pc and Armbian 5.05 software is a killer combination.

The extra horsepower of the Allwinner H3 quad core and the clean Armbian Linux implementation give you a great platform for Software defined Radio.

The $10 low cost RTL2838 dongle has an enormous amount to offer. But plugging it into a big computer laptop is not always practical

It is often better to put the RTL2838 dongle as close to the antenna as possible.

This could mean a long USB cable and voltage drop issues.

So now you can buy a $9.99 Orange Pi.one and use it as a RTL to ethernet/ opt.wifi extender.

You "just" Plug the RTL2838 into the OrangePi USB port and run a software called rtl_tcp. Which then sends whatever the RTL2838 dongle receives in packets across your local network.

I will assume people have installed rtl_tcp which from memory is part of GNU radio.

To run rtl_tcp on your OrangePi use the following command with "YOUR OrangePI's IP ADDRRESS"

@orangepione:~$ rtl_tcp -a 192.168.X.XX

Found 1 device(s):

0: Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM

Found Rafael Micro R820T tuner

Tuned to 100000000 Hz.

listening...

Use the device argument 'rtl_tcp=192.168.X.XX:1234' in OsmoSDR (gr-osmosdr) source

to receive samples in GRC and control rtl_tcp parameters (frequency, gain, ...)

This is confirming that it has found a RTL2832 dongle and has set it to 100Mhz and it is now listening on IP address of the OrangePI 192.168.X.XX and on port 1234.

Next we need to tell our network attached computer to use a Software Defined Radio software to talk to the RTL dongle accross the Network.

I am using Ubuntu and It comes with the absolutely Magical GQRX SDR software. This is a magnificent Open Source project that never ceases to amaze me.

In GQRX you need to set the Remote dongle that is sending TCP packets accross the network as the device that GQRX will communicate with.

We do this by pasting the message part from the rtl_tcp output into GQRX.

'rtl_tcp=192.168.X.XX:1234'

In GQRX configure i/o devices select "RTL-SDR Spectrum Server"

You will see a editable box that says

rtl_tcp=localhost:1234

You need to change localhost to the network IP address of your OrangePi/Armbian with the RTL dongle connected.

ie

rtl_tcp=192.168.X.XX:1234

If everything is running GQRX should appear.

It seems to crash a bit whilst I was mucking around getting it to work and I had to go and kill off the zombie GQRX before it would let me try again.

GQRX should now work as if the RTL2832 dongle was directly connected via a USB connection. You can change all the software defined radio setting on the virtual connection the same as on the real connection.

It seems to take one second for the remote commands to change frequency etc to be relayed across the network to the OPi connected RTL dongle. But once you get used to it its fine.

I have only played and listened to some local FM stations so far. I would definitely say it APPEARS the OrangePI.pc has enough grunt to run the rtl_tcp without too much lag or delay.

For an experimental system it is a lot of fun.

Next I will be setting up my Soft66RTL HF Upconverter RTL dongle from Japan (great product) to my OrangePi and see if I can get the lower HF bands successfully to stream across my network correctly.

Once again a big thanks to the Armbian Team and also the excellent work by the GQRX team

svkatielee · April 6, 2016

Nice ideas.

I presume that you intend to put the antenna, RTL dongle and Orange pie up the antenna mast and have the only cable to it be a Cat5E network cable with PoE, Power over Ethernet? It may require custom PoE injector/extractor but should be an efficient setup.