If the HackRF One is the most versatile, the RTL-SDR is the most affordable. RTL-SDR Blog V3 R820T2 RTL2832U 1PPM TCXO HF Bias Tee SMA Software Defined Radio with Dipole Antenna Kit This bundle is only available on Amazon and is noted as a limited time offering, so be sure to check the link for availability. The combination of the Nooelec NESDR SMArt SDR coupled with the Ham It Up up-converter will allow this rig to operate from 100kHz to 1.7GHz. The bundle includes the Nooelec NESDR radio, a Ham It Up up converter, 3 different antenna, an impedance matching balun, and interconnect adapters. The Nooelec NESDR Smart HF Bundle is a complete and affordable kit that includes everything you need receive HF bands. SMA female clock input and output for synchronization.software-controlled antenna port power (50 mA at 3.3 V).software-configurable RX and TX gain and baseband filter.compatible with GNU Radio, SDR#, and more.8-bit quadrature samples (8-bit I and 8-bit Q).Designed to enable test and development of modern and next generation radio technologies, HackRF One is an open source hardware platform that can be used as a USB peripheral or programmed for stand-alone operation. HackRF One from Great Scott Gadgets is a Software Defined Radio peripheral capable of transmission or reception of radio signals from 1 MHz to 6 GHz. Below is additional information from the vendor describing the HackRF One SDR Radio. This bundle includes everything you need to get the SDR up and running: adapters to connect a wide range of antennas to your HackRF One, including F-connector, N-connector, BNC and PAL antennas. Although the HackRF One SDR can both transmit and receive, it is only half-duplex, meaning it can transmit OR receive, but not both at the same time.