Note: The subsequently presented circuits, components and measurement equipment were not optimized. Some were derived from experimental results and actuated under my particular local conditions. A successful reproduction elsewhere cannot be ensured.
1. MF RX DL3ARM
As a receiver the TS570 with additional preamplifier and preselector is employed. The idea of using the mechanical filter type FZ02 arose while designing the receiver for the MF grabber which is now in use at DM4TR. I would like to acknowledge Wolfgang DH1AKF for contributing the following FET circuit:
Preselector and preamplifier with mechanical filter
Frequency response of the filter obtained by connecting the SDR-stick “Nano”. By skipping the RF section the signal is directly fed to the ADC inside the stick.
In this configuration the SDR-stick works from 0-1 MHz