About two years ago, I spent an evening and hacked together a simple program for taking recordings of HF-FAX transmissions and converting them into image files. The other day, I thought I’d dust that code off, but I couldn’t find it. So, instead, I reimplemented it from scratch. There is an interesting bit of math that I finally understood when I reimplemented it, which actually worked out rather well. I took a recording that I made of the New Orleans Coast Guard’s station broadcast, and it turned into this picture:
I’ll have to work a bit on the sync detection and scaling, as well as rectification, but it’s looking pretty good for the small amount of effort I’ve placed in it.