A few moments ago I was able to receive the Radio-DARC-transmission from 11:00 CEST, Sunday, June 13, 2021, with my homebuilt SDR, that just became ready for a first try on the antenna.
The received sound was loud and clear.
The SDR comprises an anti-aliasing-filter, a preamp, a NUCLEO-STM32H743ZI evaluation board, an active loudspeaker and nothing else.
Reception of the AM transmission at 6070 kHz is done by undersampling the signal from the antenna by using the internal ADC of the microcontroller.
IQ-Downmixing, Filtering and AM-Demodulation is done by using the internal peripherals of the STM32H7 and by running a very small program with only a few lines of code.
A detailed explanation will come soon…