NOAA APT Decoder

Decode analog, APT signals from the NOAA weather satellites.

Images are decoded from WAV files with a sample rate of 20800Hz. Files can be resampled using two methods.

Installation on Linux

sudo apt install git
pip install pillow numpy scipy
git clone https://github.com/zacstewart/apt-decoder
cd apt-decoder

Resampling

• Method 1: Using a Python script with no additional dependencies.

  cd apt-decoder
  python3 resample.py recording.wav resampled.wav
  

• Method 2: Using SoX and a bash script. This method is faster and filters the signal to improve the quality of the image.

  sudo apt install sox
  cd apt-decoder
  ./resample.sh recording.wav resampled.wav
  

Usage

cd apt-decoder
python3 apt.py resampled.wav image_out.png

Images will probably look upside down if the satellite passed from south to north instead of north to south. In fact, the following examples are upside down.

Examples

Alternatives

You can also try wxtoimg but looks dead.

Alternatively atp-dec/apt-dec works really good. Keep in mind that the 1.7 release looks newer than the repo's master branch.