HackRF One from Great Scott Gadgets
Overview: Software Defined Radio transmission or reception of radio signals from 1 MHz to 6 GHz.
Price $328.00 https://hakshop.com/collections/wireless-gear/products/hackrf
About Video https://youtu.be/R0xEnIXCl2g
Main Page https://greatscottgadgets.com/hackrf/
Documents https://github.com/mossmann/hackrf/wiki
Recommend Reading https://github.com/mossmann/hackrf/wiki/Getting-Started-with-HackRF-and-GNU-Radio
FAQs https://github.com/mossmann/hackrf/wiki/FAQ
GitHub https://github.com/mossmann/hackrf
Forums https://github.com/mossmann/hackrf/issues
Hak5 Videos
Getting Started With The HackRF, Hak5 1707
Using A RTL-SDR To Learn About The GSM Network Around You, Hak5 1621

Michael Ossmann Videos
SDR with HackRF One, Lesson 1 – Welcome – 720p
SDR with HackRF One, Lesson 2 – DSP – 720p
SDR with HackRF One, Lesson 3 – What is a Decibel – 720p
SDR with HackRF One, Lesson 4 – Mysteries – 720p
SDR with HackRF One, Lesson 5 – HackRF One – 720p
SDR with HackRF One, Lesson 6 – Complex Numbers – 720p
SDR with HackRF One, Lesson 7 – Complex Numbers in DSP – 720p
SDR with HackRF One, Lesson 8 – On-Off Keying – 720p
SDR with HackRF One, Lesson 9 – Aliasing – 720p
SDR with HackRF One, Lesson 10 – Filters – 720p
SDR with HackRF One, Lesson 11 – Replay – 720p