PandwaRF (formerly GollumRF) is a RF analysis tool with a sub-1 GHz wireless transceiver controlled by a smartphone or a PC. Its purpose is to capture, display & transmit RF data very easily. It can be connected to an Android smartphone using BLE or USB, and to Linux using USB. It is based on the well-known RfCat & Yard Stick One tools with the Texas Instruments CC1111 RF transceiver, but with a lot of new features, making PandwaRF the perfect portable RF analysis tool.
Cheaper, simpler, smaller than a SDR.