No RF filter has been added yet. The project currently contains an RP2040 and a 47 kΩ resistor; I’m blocked from editing because no ACUs are available.

Before implementation, the filter still needs key requirements: intended center frequency (likely 900 MHz, not 900 mHz), bandwidth, 50 Ω source/load impedance, filter type, required rejection/insertion loss, RF transceiver, and antenna interface. Once ACUs are available, I can select a practical matching/filter topology, add datasheet-backed RF components, connect it between the radio and antenna, and verify the schematic.