logo elektroda
logo elektroda
X
logo elektroda
Advanced Search
logo elektroda

AM / FM tuner TEF6686 controlled from the computer

dktr 49056 80

TL;DR

  • A TEF6686-based AM/FM tuner module is controlled from a computer and can output analog audio L+R or MPX depending on configuration.
  • An ATmega328 bridge translates I2C commands for the tuner into UART, and xdr-gtk provides PC control.
  • The module costs about PLN 100 and offers adjustable de-emphasis, filter settings, great sensitivity, and selectivity.
  • Remote operation uses a Raspberry Pi and a sound card with line-in, letting the tuner run over the Internet from a separate installation.
Generated by the language model.
ADVERTISEMENT
Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
Report a violation of the law
Reply Cool? Ranking DIY | New topic
Notify about new articles
📢 Listen (AI):
  • #31 20248400
    armin12
    Level 5  
    Posts: 60
    Rate: 2
    Board Language: polish
    It worked. Thanks for the help.

    Interface of the XDR-GTK program with RMF FM signal at 100.100 MHz.
  • ADVERTISEMENT
  • #32 20250286
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    armin12 wrote:

    How is it not analog? DAB + is not there, so it is probably not a digital radio. There is AM and FM also analog radio only.


    The FM radio is analog, the tuner described here is a device with a digital signal processor. In details, it differs from regular FM radio, but in blocks it is the same. It has high sensitivity and selectivity, and in addition, digital processing significantly improves the reception parameters.
  • #33 20250326
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    armin12 wrote:
    It worked. Thanks for the help.

    Interface of the XDR-GTK program with RMF FM signal at 100.100 MHz.


    The signal graph in your screenshot looks strange. Anything at all changing? This is how it looks for me.

    FM radio signal displayed on the XDR-GTK program screen, tuning to RMF FM 95.3 MHz.
  • #34 20251042
    armin12
    Level 5  
    Posts: 60
    Rate: 2
    Board Language: polish
    This is what it looks like at 120 kW stations from the nearby (10 km) RTCN in Sucha Góra, for example, this is how the Three looks like:

    AM / FM tuner TEF6686 controlled from the computer

    Yes, Jedynka - just like RMF FM

    AM / FM tuner TEF6686 controlled from the computer

    At weaker local stations, not broadcasting from RTCN, and from other venues, a bit changes, e.g. here Złote Przeboje:

    AM / FM tuner TEF6686 controlled from the computer

    Trendy Radio here:

    AM / FM tuner TEF6686 controlled from the computer

    And this is what it looks like at distant stations. Here is One of the Holy Cross:

    AM / FM tuner TEF6686 controlled from the computer

    In places where there is nothing (noise) it looks like this:

    AM / FM tuner TEF6686 controlled from the computer


    Generally, this FM tuner receives very well, it is very selective. Yesterday evening I caught RMF FM, Jedynka and Trójka from Raszyn, 300 km away from me. The three of them were in a slightly humming stereo, sometimes even loading RDS. It is weak on AM, but it is probably because the antenna (Dipol 3 RZ B) is an antenna for the VHF FM band. All it catches is some Russian station on 999 kHz. At 225kHz, where the One should be, I only have noise.

    And what are the RF + and IF + options? This is some gain, when I click, the amount of dBf increases, but there is no difference in reception.
    Maybe someday, when I have some time, I will record and throw some bandscan.
  • #35 20251213
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    You must have some very old soft in this atm, the signal level varies by 1 dB, you have no decimal values, and that was done quite a long time ago. Note that in my graph you can see what is happening between 77 and 76dBf.
  • #37 20251895
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    dktr wrote:
    You must have some very old soft in this atm, the signal level varies by 1 dB, you have no decimal values, and that was done quite a long time ago. Note that in my graph you can see what is happening between 77 and 76dBf.


    What could such differences result from?
    I also bought this tuner module, but I did not run it - I was wondering what to control it? What's going to be the best?
  • #38 20251997
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    Well, I wrote that he has an old soft in the processor, which is between the tuner and the computer. In the first post, I turned on the soft, which has it already covered.
  • #39 20252015
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    Will Arduino Mini or nano be sufficient to work with this FM tuner module?
  • #40 20252114
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    I do not know what is on these "arduino mini", because there is a lot of it and it is not known what it is about. Atmega328 is enough for this task.
  • ADVERTISEMENT
  • #41 20252231
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    @dktr
    I checked - these Arduino have Atmega328-20AU (SMD case), Arduino Nano (and clones) and ATmega328P-U (DIP case) Arduino Uno (and clones).
    Did you do everything yourself with this microcontroller? Do you have any buttons and LCD connected?
  • #42 20252467
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    I don't use arduino, I prefer bare atmega. But when the m328 sits there, it will be fine. This is how I connected displays, buttons, encoder, IR receiver, etc.



  • #43 20252527
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    How did you connect with Denon?
    I2C or what else? My guess is that you have data from the driver on the display.
  • #44 20252659
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    Nothing, only the housing, transformer and cinch sockets remained from the Denon.
    Decorated front-panel buttons on universal boards, VFD display from a fiscal printer :)

    AM / FM tuner TEF6686 controlled from the computer

    AM / FM tuner TEF6686 controlled from the computer
  • #45 20253728
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    It turned out nice :)
    It probably sounds like Denon - ie sensitivity, selectivity and other parameters?
  • #46 20254028
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    It sounds like TEF6686. Originally the Denon worked, but its parameters were much worse than that of TEF - when it comes to sensitivity and selectivity. In addition, it already had a bright VFD display and almost nothing was visible, so I treated it as a housing donor :)
  • #47 20308903
    armin12
    Level 5  
    Posts: 60
    Rate: 2
    Board Language: polish
    I recorded Bandscan on TEF 6866, in Krosno, Podkarpacie. The antenna is a Dipole 3 RZ B. I invite you to watch:

    https://www.youtube.com/watch?v=Jm6o4VDd2Gw&ab_channel=AdamosDX

    To display caught stations and transmitters on a regular basis, turn on subtitles.

    The TEF 6866 is a very good, sensitive and selective receiver. It receives a lot of very distant stations, as evidenced by the video I shared
  • #48 20309089
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    Decent results, have you tried with a better antenna?
    I used the Quad in my apartment and it sounded pretty good - I have a maximum of 7-8 km to a dozen or so stations, and I would be able to receive it on the wire. But there is a difference - a good FM tuner compared to a home theater.

    I bought the TEF6686 FM tuner module, but I didn't start it - from what I can see, the simplest controller should handle it (in the sense of the simplest Atmega).
  • ADVERTISEMENT
  • #49 20724524
    dariuszkulmaczewski
    Level 4  
    Posts: 4
    Board Language: polish
    Hello,
    I purchased a tef 6686 fm tuner and would like to swap in my android car radio. What will I need to make it work, any drivers, will the app that is preloaded handle this module?
  • #50 20724570
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    It doesn't work like that, you swap it and that's it. It communicates over i2c and I doubt you'll find an android app that supports this tuner that way.
    We're in a period of elevated tropospheric conditions right now and this tuner does a pretty good job.



  • #51 20724629
    dariuszkulmaczewski
    Level 4  
    Posts: 4
    Board Language: polish
    Is there a way to embrace it?
  • #52 20769477
    henryk2f
    Level 12  
    Posts: 130
    Help: 2
    Rate: 14
    Board Language: polish
    >>19665798 I also have such a radio, after connecting to a 4 x 20,5 m square antenna on 4 masts h=7,5 m I have all-day reception of UKF stations from Gdansk to Krakow (and Krosno also catches). The radio is great. I installed CH340 driver on PC and comp sees this radio. Now I'm just looking for a good software to control the radio from PC - what can you Fellows suggest? In the first photo the TEF6686 radio, in the second photo the current consumption at 5 VDC. I also attach a list of stations heard in Warsaw on this radio connected to the aforementioned antenna.

    TEF6686 digital radio displaying EskaROCK station against a background of radio station list. Current meter display showing 5.15 V and 0.335 A. .
    Attachments:
    • Stacje UKF w Warszawie 25.09.2023.xlsx (16.71 KB) You must be logged in to download this attachment.
  • #53 20772110
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    The 4x20.5m antenna is not an antenna for the FM band, better results would be given by an antenna for this band.
  • ADVERTISEMENT
  • #54 20772176
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    Quote:
    after connecting to a 4 x 20.5 m square antenna on 4 masts h=7.5 m I have all day reception of UKF stations from Gdansk to Krakow (and Krosno also catches). Radio great.

    This kind of reception is very difficult without elevated conditions from central Poland on Yagi antennas on the right bands with considerable gain let alone on a piece of wire for KF bands. Someone is misrepresenting the truth here.
  • #55 20772385
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    Here's the thing - the antenna does not work better because it is large only works if it is effective.
    DX are possible, but on a matched antenna with high gain - the condition, of course, is elevated conditions in the troposphere.
    Sa in the network information keidy such conditions are forecast - I was able to receive FM stations distant about 230km 3 to 3 hours before the storm from the direction of the transmitter. Antea was a dipole with a 300 ohm wire and a tuner built into a portable radio.
  • #56 20772775
    henryk2f
    Level 12  
    Posts: 130
    Help: 2
    Rate: 14
    Board Language: polish
    >>20772110
    This is how I get reception downstairs - the signal is better from this 4x20.5m antenna - probably because the signal from the omnidirectional UKF antenna (mounted at about 9m high) is split by 3 antenna splitters along the way. Upstairs, as I connect directly to this UKF antenna, the signal is better from the UKF antenna - see the table in my post.

    Added after 5 [minutes]:

    dktr wrote:
    Quote:
    after connecting to a 4 x 20 square antenna,5 m on 4 masts h=7,5 m I have all day reception of UKF stations from Gdansk to Krakow (and Krosno also catches). The radio is great.

    This kind of reception is very difficult without elevated conditions from central Poland on Yagi antennas on the right bands with considerable gain let alone on a piece of wire for KF bands. Someone here is mistaking the truth.


    But such reception I have (and this is not tropo, but continuous reception) - unbelievers I invite you to a site visit :)
    Please compare my performance (--> table !) when connected to the KF antenna downstairs and the performance when directly connected to the omnidirectional UKF antenna (the signal from this antenna reaches the socket downstairs after passing through 3 signal dividers).
  • #57 20772781
    dktr
    Level 26  
    Posts: 930
    Help: 45
    Rate: 702
    Board Language: polish
    This is another matter. Simply put, an antenna of this length will work well somewhere on KF, e.g. around 7 MHz or even 3.5 MHz, while on UKF it will be a random piece of wire having negative gain. I recommend going with this radio and, for example, a three-element yagi antenna to some mountain then only then will show what sensitivity and selectivity in TEF6686 can do.
  • #58 20772788
    henryk2f
    Level 12  
    Posts: 130
    Help: 2
    Rate: 14
    Board Language: polish
    sq3evp wrote:
    A 4x20.5m antenna is not an antenna for the FM band, better results would be given by an antenna for this band.


    This is how I get reception downstairs - the signal is better from this 4x20.5m antenna - probably because the signal from the omnidirectional UKF antenna (mounted at about 9m high) is split by 3 antenna splitters along the way. Upstairs, as I connect directly to this UKF antenna, the signal is better from the UKF antenna - see the table in my post.
  • #59 20773442
    sq3evp
    Level 39  
    Posts: 6334
    Help: 210
    Rate: 833
    Board Language: polish
    This might be so despite the antenna mismatch, but better results would be for a yagi for the FM range.
    A omnidirectional antenna has too little gain to play with DX.
  • #60 20774278
    henryk2f
    Level 12  
    Posts: 130
    Help: 2
    Rate: 14
    Board Language: polish
    I agree with my colleague, I need to talk to my neighbor (he has a flat roof at the height of the 3rd floor) to make the roof on his house available to me for such tests (TEF6686 + Yagi antenna) and then I will enter this performance in the table (or rather I will create a new one, because after all I will have to add another column - azimuth of the Yagi antenna) :) .
Reply Cool? Ranking DIY | New topic
Notify about new articles
📢 Listen (AI):
Report a violation of the law

Topic summary

✨ The TEF6686 AM/FM tuner module, available for around PLN 100 from Chinese suppliers such as AliExpress, is a highly sensitive and selective digital FM tuner with analog audio output (L+R or MPX). It is controlled via I2C communication, often interfaced through an Atmega328 microcontroller that translates I2C commands to UART for PC control. The module supports adjustable de-emphasis, filtering, and RDS decoding, with software like XDR-GTK enabling tuning and signal visualization. Users report excellent reception capabilities, including distant stations and good AM performance, especially when paired with appropriate antennas such as dipoles or directional antennas (Yagi, Moxon). The module requires a 3.3V I2C interface with proper pull-up resistors and a 5V power supply for the microcontroller. Firmware updates (e.g., version 2.20) improve functionality and compatibility. Integration with Arduino Nano or similar Atmega328-based boards is common, with available open-source code on GitHub. Audio output is analog and must be connected to an amplifier or line-in for sound; headphones can work but with limited volume. The TEF6686 differs from simpler tuners like QN8035 or SI4703 by offering superior sensitivity and selectivity, making it suitable for DX listening and antenna testing. Users also discuss antenna matching, impedance considerations, and the benefits of directional antennas for enhanced reception. Some challenges include initial setup, firmware configuration (e.g., quartz frequency adjustment), and ensuring correct voltage levels on I2C lines. Community resources include GitHub repositories, YouTube tutorials, and Facebook groups for firmware, software, and hardware support.
Generated by the language model.
Today's popular

FAQ

TL;DR: With a –120 dBm noise floor, "TEF6686 is a completely different league" [Elektroda, dktr, #19665625; #19659203]. Update firmware, add 3.3 V pull-ups, and XDR-GTK or Wi-Fi control unlocks DX-grade AM/FM up to 300 km. Why it matters: a €20 board can rival vintage hi-fi tuners when set up correctly.

Quick Facts

• Frequency coverage: 153 kHz–30 MHz AM & 64–108 MHz FM [Datasheet, NXP, 2016] • FM stereo sensitivity: ≤2 µV (-107 dBm) typ. [Datasheet, NXP, 2016] • Module cost: PLN 67–100 (≈US$15–25) [Elektroda, simw, post #19656257] • Logic voltage: 3.3 V (I²C), analog 5 V tolerated [Elektroda, dktr, post #20251997] • I²C bus speed: 100–400 kHz selectable [Elektroda, bup00124545, post #21075906]

1. Where can I buy a TEF6686 tuner module?

Search “TEF6686 radio module” on AliExpress or similar Chinese marketplaces; prices range from PLN 67 to PLN 100 plus shipping [Elektroda, simw, #19656257; dktr, #19658014].

2. Which microcontroller works best for control?

An ATmega328 (Arduino Uno/Nano) is enough; it translates UART ↔ I²C commands. Any board exposing 3.3 V-safe I²C lines will work [Elektroda, dktr, post #20252114]

3. How do I wire the module to an Arduino?

  1. Connect SDA/SCL through 10 kΩ pull-ups to 3.3 V. 2. Tie module 3.3 V and GND to Arduino 3.3 V/GND. 3. Link audio L/R to an amplifier or PC line-in. Follow the schematic in the first post [Elektroda, dktr, post #19656231]

4. XDR-GTK shows “Waiting for tuner” – what’s wrong?

Older firmware (≤v1.18) uses different serial commands. Flash Sjef’s v2.20 firmware via USB, then select the correct COM port at 115 200 bps [Elektroda, henryk2f, post #21586701]

5. My signal meter steps 1 dB at a time.

Decimal resolution appears only in firmware ≥v2.0. Update the ATmega code from the FM-DX-Tuner repo to restore 0.1 dB steps [Elektroda, dktr, post #20251213]

6. The frequencies are offset by ~18 MHz. How do I fix this?

If your board has a 4 MHz crystal, set TUNER_TEF668X_REF_CLOCK to 4000000 in ConfigTEF668X.hpp and recompile; the spectrum then aligns correctly [Elektroda, bup00124545, post #21075906]

7. Can I hear audio through XDR-GTK alone?

No. XDR-GTK only sends control commands. Route L/R outputs to an amp or enable “Listen to this device” on the PC line-in mixer for monitoring [Elektroda, dktr, #20246285; lechoo, #20247886].

8. How sensitive is TEF6686 compared with QN8035 or TEA5767?

Tests show stereo locks at –91 dBm, RDS at –75 dBm, beating QN8035 and TEA5767 which fail under –65 dBm adjacent-channel conditions [Elektroda, dktr, #19659365; #19665625].

9. Does it really handle AM longwave and medium-wave?

Yes. Even with an FM dipole it received 225 kHz LW and city-noise MW signals; adding a proper loop improves clarity [Elektroda, dktr, post #19684703]

10. How can I use the tuner over Wi-Fi?

Install xdr-gtk on a Raspberry Pi, forward UART via TCP, and stream audio with foobar2000; public demo at dktr.pl shows <1 s latency [Elektroda, dktr, post #19656231]

11. Nothing shows without an antenna—is that normal?

Yes. With input shorted, meter rests near –120 dBm. Attach a tuned FM antenna to see stations; an unmatched wire yields negative gain [Elektroda, dktr, #19665625; #20772781].

12. TPA3255 amp makes the tuner “go stupid.” What can I do?

Digital amps radiate HF noise via the audio cable. Add ferrite beads on the minijack, keep grounds short, or use an optical isolator; after filtering, the tuner regains stability [Elektroda, bendix101, post #21585259]

13. Can I lower USB noise entirely?

Power the Arduino+TEF from a battery bank and replace USB with an HC-05 Bluetooth serial link; level-shift HC-05 RX to 3.3 V using 1 kΩ+2.2 kΩ divider [Elektroda, bup00124545, post #21075906]

14. What’s the edge case that bricks the module?

Driving SDA/SCL at 5 V without pull-ups can latch the I²C bus and corrupt the RF front-end; always keep logic at 3.3 V [Elektroda, bup00124545, post #21075906]
Generated by the language model.
ADVERTISEMENT