Pi Software Controlled Radio - SCR


* Be sure to read comments below. As things change I will update comments.

Along with the many HATs and such that I bought from MicroCenter when I got my first pies, I picked up a usb software controlled radio or SCR. The cost was only $23 and I thought it would be fun to play with. At that point I was thinking only radio, AM/FM but it turns out it can do other frequency monitoring. This is not all inclusive, it is just some of the things I did this weekend to get it to work.

First off, the radio is an AdaFruit http://adafru.it/1497.
The radio receiver itself is from what I can determine Realtech Semiconductor corp 0bda:2832/2828..
I believe it was installed by default in /etc/udev/ruls.d/rtl-sdr.rules file.

I went about installation in probably the wrong way which did a full compile/install of GQRX.
This full install did not work but I am sure that was probably due to inexperienced linux operator errors.

I did however also download the compressed file, extracted to a pi folder called SCR and it ran after that by pointing directly to the GQRX file once I followed the library steps in the readme.txt file.
The install packed file software I downloaded was here:
After i downloaded I ran the installs it said in the readme file.
sudo apt update
sudo apt install gnuradio libvolk1-bin libusb-1.0-0 gr-iqbal
sudo apt install qt5-default libqt5svg5 libportaudio2

The library installs took quite some time, so be prepared to wait around a bit.
I did not however perform the step in the readme about copying the rules as mentioned above, but this may depend on your radio type.

I was able to launch GQRX, set the frequency to a local FM station.
To do this I simply typed in 96495.000 (or something thereabouts) in the Frequency text box and hit the play button.
This put me in the FM range around the lower end of our FM dial.
The waterfall showed a full stream around 96.5 with strong audio... "somewhat lacking audio" but it was audio. This is probably to be expected since I was using the tiny 4 inch antenna that came with the unit.
The audio was very faint until I increased the gain slider in the app to increase the decibels.
On the mode selector, FM mono seemed to work much better than FM stereo or FM narrow. Stereo was pretty choppy.
If you turn on RDS under the "View" tab, you can see information about the station and what is playing. That is kind of a cool feature that appeared to work. It will give you another tab on the right panel.

The USB dongle for the SCR seemed to get quite warm in the pi. It may be just the way it works but not something I want to leave on all the time. Possibly due to having such a small antenna (that came with the unit) or not enough ground plane.
It did cool down after I stopped receiving. I also noticed that on occasion the little power indicator would show up on the pi so it was probably consuming quite a bit of power from the power line and pi itself

One thing I did like however was the ability to set labels and add bookmarks. This allowed me to set up a bookmark for every radio station I could find and label it as radio. Turning off the checkbox on everything but radio makes only radio stations appear for selection.
A quick search on the internet allowed me to find many of the frequencies in the area like police, fire, news, radio but I was not really able to bring in any of the cooler things. Again, probably due to the antenna.. or they were not broadcasting at the time.

Cool little pi toy though. I reset the pi and only tried the "download install method" above and those seemed to be the correct steps to get it to work.
Beuller... Beuller...

abitowhit's picture

So it appears my first attempt caused some network issues on the pi, so I have loaded a new image and will start from scratch or load on a different pi. I was thinking of possibly having just the radio software on a standalone pi with a 3.5 inch monitor. I am fairly sure it was due to the installs to get the radio to work. It does provide a TCP interface so possibly there are conflicts. I may try it on a pi zero but not sure it has the horsepower. I will create a build sheet whichever route I take to make installs easier.