The subject of Software Defined Radio (SDR) has been introduced to the RSGB syllabus for students at each of the three levels.
Most modern radios now sport colourful waterfall displays, and there is a wide range of SDR dongles available from a few pounds to several thousand.
The SDR manufacturers specifications look impressive but what do all the numbers mean? To answer that question, I will start with a little history, describe the three dongle I own, and compare the specifications I felt were important when I was deciding what to purchase