Many radio amateurs in practice use two receivers, one portable and the other a fixed receiver with a PC control facility. The Elektor DSP radio can operate in either capacity, with a USB interface giving the option of PC control. An additional feature of the USB interface is that it can be used as the source of power for the receiver, the audio output being connected to the PC’s powered speakers. To allow portable 6 V battery operation the circuit also provides for an audio amplifier with one or two loudspeakers.
Features
– no set-up adjustments required
– Si4735 DSP receiver IC
– ATmega168 microcontroller
– USB interface using FT232R
– backlit 2 x 16 LCD panel
– battery voltage 4.8 to 6 V
– current consumption approximately 50 mA
– 3.3 V internal power supply
– power from PC over USB interface
– stereo audio output
– stereo audio amplifier (2 x LM386)
– RDS display
– AM from 153 kHz to 21.85 MHz
– automatic station search
– antenna signal strength indication in dBµV
– signal strength meter connection
– diode switching of AM band
– automatic tuning of AM resonant circuit
– switchable AM bandwidth
– optional PC control over USB
– tuning using rotary encoder
– four control pushbuttons
– station memory (30 AM presets and 30 FM presets)
– open-source firmware (free download)
– in-system programming interface
– printed circuit board available ready-populated and tested
The assembled and tested PCB is US$240.40.