Receive and decode images from weather satellites

noaa-apt takes a recorded WAV file and decodes the image. As an example, this is a WAV file I recorded using GQRX using a RTL-SDR and a double cross antenna. When loading that file on noaa-apt, you get as a result this image.


NOAA satellite reception is fun, cheap and relatively easy. You can buy a RTL-SDR for less than 30USD, it looks like a USB drive but it has a connector for antennas. Using SDR software like GQRX and SDR# you can receive FM signals, for example broadcast FM (around 100MHz) or better, receive APT signals from NOAA satellites (around 137MHz) and then decode them with noaa-apt.

I made noaa-apt because WXtoIMG, the most popular decoding software, it's propietary and no longer maintained, but you can get old recovered versions from an unofficial website. Also, the steps required to decode WAV files on it are not that obvious.

There are lots of really good Alternatives, but all of them require compilation, Python or don't provide graphical user interfaces. So I wanted to create an easy to use alternative for Windows users, being useful to advanced GNU/Linux users doing some kind of automation too.


WXtoIMG has lots of features you might want that noaa-apt does not have, for example false-color images and live decoding. Anyways, the quality of the black and white image should be the same. Currently, my program has problems doing accurate map overlays, but you can get nice results if you play a bit with some settings.

If you get some kind of error or bad result open a Issue or send me an email. Also I'm not a native english speaker so please let me know where I made mistakes. Both the code and the website is on the GitHub repository.




  • Decode raw images from WAV files.
  • Add map overlays with countries, states, provinces and lakes.
  • Really easy to use GUI (at least easier than most decoders).
  • Histogram equalization.
  • You can disable syncing and export every step of the decoding process, useful for corrupted recordings.
  • Telemetry band reading.
  • Resample WAV files preserving modification timestamps.
  • Modify timestamps of files.
  • Edit filter parameters from a configuration file.
  • Rotate the output image, in case of ascending (South to North) passes.