[[https://www.rtl-sdr.com/about-rtl-sdr/ RTL-SDR]]- Very low cost (~$30) receiver operating from about 52MHz to 2200MHz.
[[https://greatscottgadgets.com/hackrf/one/ HackRF One]]- Capable of transmission or reception of radio signals from 1 MHz to 6 GHz. Open source hardware platform that can be used as a USB peripheral or programmed for stand-alone operation. Cost ~$340
[[https://www.ettus.com/all-products/ub200-kit/ Ettus Research USRP B200]]- Universal Software Radio Peripheral with continuous frequency coverage from 70 MHz –6 GHz. Wider bandwidth and higher resolution ADC/DAC than the HackRF; cost with enclosure ~$875.