This time I will prtesent you how to make a AM/FM Radio, based on radio module with TEF6686 chip from NXP. This miniature module has amazing possibilities, great sensitivity and selectivity, adjustable de-emphasis and filter. It has a output analog audio L + R, or MPX, depending on the configuration.
Also, this module has an I2C communication protocol, so the simplest way to communicate with a personal computer is an Arduino microcontroller with the appropriate code uploaded. For the PC there is an application called XDR-GTK through which we control the module. I mounted the module on proto board so I could connect it to the Arduino more easily.
So to make a complete radio receiver we need only a few components:
- radio module with TEF6686 chip
- Arduino microcontroller
- Two capacitors
- Audio jack and cable
- and Personal Computer
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Now I will describe the whole procedure in detail:
First of all, let me mention that on the Internet you can find more Arduino codes from different authors, and also versions of the XDR-GTK application. I first tested almost all of them, and this time I will describe only one way, which, at least in my specific case, was the simplest and worked best and most stably.
On the GitHub page:
https://github.com/marsel90-1/NXP-TEF6686_F8602_F8605-Arduino-Radio
it has everything we need for this project.
A few words about the Arduino code: there are two types of radio modules with F8602 and F8605 version of the chip. In my case it is F8602 chip version.
Similarly, the appropriate code "TEF6686-arduino-F8602" is uploaded to the Arduino microcontroller. How to upload the code has been described many times before in my videos, and there are also great tutorials online, so we will skip this step.
Next, the TEF-GTK.v1.1.2 application should be installed on the PC, actually you just need to unzip the archive to a certain location and extract the shortcut to the desktop.
Now we need to determine on which port is installed the Arduino microcontroller, because we will need this information later.
The consumption of the Tuner module is about 100 milliamps, so we can power it directly from the microcontroller. Now we start the PC Application, and select the communication method, in this case through serial port COM 6. We press OK and the radio starts working on the frequency that we can previously define in the settings tab.
In the central part you can see a graphic representation of the quality of the reception signal. The "STEREO" signal is also displayed, and if there is an "RDS" signal, that information is also marked with an appropriate sign. We can follow the RDS text in the upper right corner. There are also several buttons for setting the Antenna, AGC, and bandwidth.
The next super useful option is "Spectral Scan" wich alows us to scan the entire FM area.
TEF-GTK appplication also supports external Applications. One of them is "Station List" aplpplication, that shows the name of current radio station, the country from wich it is broadcast, the strenght and location of repeater, and other useful informations.
Also a useful external appplication is "RDS SPY" with the help of wich we get detailed information about the RDS signal.
And finally, a short conclusion. First of all, let me mention that for the FM band I used a 137 Mhz V-dipole antenna for weather satellites reception, as the closest option since I don't own an antenna for FM, and for the AM area I used a so-called Loop Over Ground Antenna that works perfectly with my amateur radio receivers. To my great surprise, the FM reception is excellent, even when I used a short wire of about 50 cm as an antenna. I was especially surprised by the sensitivity and quite solid reception of distant FM radio stations.
This receiver is superior to the Arduino radio receivers with RDA and TEA chip that I have built, and in my opinion it also has better reception than the well-known portable radios from the brands XHDATA, DEGEN, TECSUN, especially in terms of sensitivity weak FM signals.
