Software Defined Radio, or SDR, is a way of building radios that replaces much of the radio hardware with software and allows customization and re-configuration without having to upgrade the radio itself. A number of commercial systems for amateur radio are available as well as modular systems from TAPR and others but they’re mostly all high-performance systems that are appropriately priced. Luckily, if you have more modest needs there are now ways to get into SDR without spending thousands.
One of those ways is via a cheap ($30) USB dongle originally intended for receiving EU digital TV. The dongle takes care of RF signal detection and the A/D conversion, you provide the software on your computer to turn the raw digital information into something useful. I haven’t got my dongle yet so I’m not sure which software I’ll be using, but I will report back on how it goes once I settle on something.
The USB dongle I purchased is available on eBay: EzTV688 USB DVB-TV Receiver. Some people are using GNURadio software to build a working SDR, but it’s more of a toolkit than a plug and play radio, so I may not go that route at first. Over on Reddit there’s a RTL-SDR community that covers SDR using this dongle and rtl-sdr software from Osmocom. Hack a Day also posts on cheap SDR in their radio hacks category. Software for SDR runs on Linux, Windows and Mac OS X, so you can likely keep using what your already have. I will probably use my WinXP laptop at first but that may change if it lacks sufficient CPU power.
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