# FreeCAD tracker models **Rubber duck antenna**: - `antenna_base` - base for rubber duck antenna, to be printed with PETG filament. - `antenna_cover` - cover for rubber duck antenna, to printed with TPU filament. 👉 Rubber duck antenna spiral widing was done with 1.3mm copper wire on 8mm aluminium scaffolding tube. **Tracker case**: - `aprs_tracker_e22_base` - base for tracker case without battery compartment. - `aprs_tracker_e22_cover` - upper cover for headless tracker without any controls. - `aprs_tracker_e22_antenna_ring` - TPU filament ring placed under antenna. - `aprs_tracker_e22_base_battery_lid` - lid for battery compartment. - `aprs_tracker_e22_base_battery` - base for tracker case with battery compartment (for single 18650 with charging + dc-dc 5v converter). - `aprs_tracker_e22_cover_dv` - DV cover version with holes for screen, encoder, ptt button, speaker, mic. - `aprs_tracker_e22_encoder_knob` - knob for encoder.