I recently returned to shortwave listening after a few decade absence. I discovered computer controlled receivers. These, with associated software, are very efficient at looking through a large number of frequencies with possible catches in a short time.

I also discovered Digital Radio Mondiale (DRM). It was difficult for me to get it to work, but when I did, how wonderful! You either receive the signal or you don’t. If you do, it is crystal clear!

See http://www.drm.org/ and http://drm.sourceforge.net/ and http://www.drmrx.org/ and http://www.dxtra.org/.