Barcode challenge for radio operators

[Scott Harden] came across a few posts about QR code matrix barcodes coming through on the 40m baud radio band. A few operators had captured the signals and assembled them into the code block seen above but they weren’t able to get a clear enough shot for a smartphone to decode the image. [Scott] took on the challenge and decoded the mysterious message himself. He tried some graphic editing to separate and enhance the color channels in order to up the contrasts of the image. This helped, but still couldn’t be read automatically. In a move similar to those seen in Hackaday’s own barcode challenges he dropped the image into Inkscape so that he could manually clean it up. Once it was overlaid on a grid the job was pretty simple. the left side did require some more image manipulation and precision”squinting” to eliminate interference from the vertical banding, but he managed to get the message. We won’t spoil it here in case you want to take on the challenge yourself. Good luck!


  1. it isn’t “40m baud band” it’s the 40m band (as in 40 Meters wavelength), in digital mode (looks like a PSK31 digital mode waterfall maybe)

    -Jimmy, ke5tuz

  2. Shane says:

    Pro tip: When your eyes start hurting from all the squinting, use wax paper or tracing paper. Works for seeing faces and reading words in blurry photos as well.

  3. ftk says:

    Why not just reproduce the code pixel by pixel in like… mspaint, and resize it ?

  4. spiderwebby says:

    roborealm it.

  5. o says:


    Also, why would someone use this as a digital mode? Seems rather odd and complicated…

  6. Owen says:

    It’s Yaesu’s first attempt at viral/social marketing for their amateur radio products.

  7. @ o
    if you mean the barcode, it’s just for fun.
    if you mean the waterfall type output, here’s a basic explanation for the curious:
    the waterfall is a view of the the different data streams at different operating tones – it allows multiple “channels” on the same frequency by using a different audio modulation.
    The view shown allows the operator to graphically see all possible data signals on a frequency, then select it to open a Comm. From there it is real-time text based communication, as well as basic file sharing.

  8. JEDITALIAN says:

    all you gotta do is cross your eyes and you can read it.

  9. DarkFader says:

    For part 2, the decoded QR has some encoded text in it too… bah :)

  10. ewan says:

    here is the program used to do this stuff:

    a famous example is the aphex twin image.

    the face is at about 5:25

  11. zool says:

    cool, you could put this in music and have secret messages
    paul is dead~!

  12. Alex Rossie says:

    pathetic that it took so long I just used dilate /erode

  13. Richard says:

    @ Owen: Any form of ‘on the air marketing’ done from the UK would be a breach of the UK amateur license conditions, as would responding to it from the UK regardless of where it came from… although of course there’s nothing to stop you receiving it.

  14. draeath says:

    So… I don’t suppose anyone wants to spoil this for those that can’t do this kind of thing themselves?

  15. Nash says:

    I DID IT! i took the image above, loaded it in photoshop, established a grid, and made a per-pixel remake by hand. i then read it from my phone… i’m rather proud of myself!

  16. Maave says:

    The decoded message is at the end of the original article.

  17. Nash says:

    also, i just found out that my QR code is slightly different than the one [scott] got. still got the same result, though… odd

  18. Joeee says:

    It says
    #Done by blacking out a Excel sheet VY 73

  19. wa5znu says:

    In 2004 was inspired by the Apex Twin image and contacted the guy who wrote baudline about it and he gave me some pointers. I did a “Visual CQ” and eventually got the visual mode ID into fldigi.

  20. Cory says:

    it links to!

  21. DarwinSurvivor says:

    Does anyone know of a *working* linux application that can decode QR codes? I’ve found many libraries (both c and python) but nothing that can be just “run” on either an image or with the webcam. The only compiled decoders I can find are for phones :(

  22. DarwinSurvivor says:

    I swear, part of google’s evil algorithm is only returning useful results until *after* I’ve asked people for suggestion!

    Needs python2, but other than that it seems to work just fine.

  23. Javier says:

    It is “WELL DONE / F4GKA QSL PSE 73″.

  24. JEDITALIAN says:

    @ewan. if coagula only converts image to sound, what converts sound to images? i want the program that is in the youtube video, but it isn’t named.

  25. JEDITALIAN says:

    nvm. found something with btjunkie and the word ‘spectrogram’

  26. JEDITALIAN says:

    eh, don’t feel like converting my entire music collection to .wav just to watch the imagery

  27. ferdi says:

    this link go to a page ware you can make QR codes
    from your mobile nr to site links or check the code from the photo input the text en see off the code are the same

  28. pissed off ham says:

    This is a neat and useless trick, bravo. One slight bitch though: If you’re going to be using obfuscating your messages with experimental encoding, please put a station ID in some kind of plaintext in your transmission somewhere. Having to go through all that just to find out the originating station is kind of bullshit, though fine with me for a one-time stunt. If this becomes a popular activity, then please put your call letters in plaintext so those of us who don’t want to solve a puzzle can know who is making the transmission.

  29. ker2x says:

    the tranmission mode used is MT-Hell

    i played a lot with that mode on 30m (10Mhz)
    never tought about transmitting QRcode, but it’s easy to do.

    The software used to display the waterfall is DL4YHF’s spectrum laboratory.

  30. Zom-B says:

    @DarwinSurvivor: Look at the ZXing project. It’s a Java implementation mainly intended for mobile phones, but with a few lines of extra code I was able to load and decode images on my pc.

  31. GameboyRMH says:

    @DarwinSurvivor: Look at Zbar

  32. Sasha says:

    How is this not detected? My iPhone read this in an instant!

    The last to numbers are 73 for all the haters out there :p

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