Here is a YouTube video about Michael Ossman Talks About the HackRF and JawBreaker Low Cost SDR Platforms, and is part of a growing collection of videos I have found to be useful. The reason is discussing the origin story and development of the HackRF and JawBreaker software defined radios and understanding science related to software defined radio.
This tutorial, "Michael Ossman Talks About the HackRF and JawBreaker Low Cost SDR Platforms" is free education you can watch, which will help you deepen your knowledge and be better prepared for licence exams, schoolwork, or operating radio equipment.