Elektor’s software defined radio (SDR) has been an unprecedented success in terms of publicity and sales, especially in the USA. The original publication in May 2007 was graced not just by favorable feedback from the radio community but also by follow-up projects like a simple tester, a VLF add-on and various software packages for tuning and decoding, like the G8JCFSDR package.
The December 2009 issue of Elektor has the long-awaited article about the auto-tuning preselector for better selectivity of the SDR and ease of tuning to stations otherwise blurred by noise and strong signals.
The project is complete with a PCB and a tuned loop antenna is also described that lets you use the Elektor SDR receiver without an outdoor antenna.
A kit of parts for the SDR Preselector is available from the Elektor Shop, it contains the circuit board and all parts, including the ferrite rod and ready wound coils.