Software Defined Radios (“SDR”) were first developed by and for the US Air Force to enhance air to ground radio communication. The SDR software performs filtering, demodulation and signal enhancement. More recently, SDRs have moved into the mainstream. Typical amateur and home uses include morse code, signal sideband, slow-scan television and packet radio. www.wikipedia.com
First, for you non-geeks, a Software Defined Radio (SDR) is a radio where the typical radio hardware has been replaced by software. This allows you to turn any computing device (laptop, smartphone, etc.) into a radio. With an SDR, first responders and others cancommunicate with anyone, anywhere – no cell phone towers necessary. The Wireless Innovation Forum wrote a short paper with a thorough overview.
Most of the SDR kits available on the market today assume that you have some level of technical knowledge. Many of the kits are USB peripherals that require programming knowledge to implement. Some are full kits with limited functionality others are pc boards for enhancing existing radio hardware. Bliley Technologies wrote a good summary of the various SDR kits available in 2016 and again in 2018. In the years spanning these two reviews, the technology had developed significantly.
And, that technology continues to develop. There is a new SDR solution coming soon that brings this high-tech device into the hands of all of us – using your smartphone as the base components. i-BLADES is developing an SDR Smartblade that will snap onto your i-BLADES Smartcase, transforming your smartphone into a two way radio. How cool!