The master clock dictates the frequency accuracy of the transceiver. The service manual instructs technicians to measure the reference frequency at a designated test point and adjust the internal TCXO electronic trimmer until the frequency reads exactly 122.880 MHz (or the specified sub-harmonic). 2. Receiver Sensitivity Calibration

Faulty relays can prevent power from reaching the antenna connector on specific bands. The Main Unit (RF/Digital Core)

use lead-free solder (ideally Sn-3.0Ag-0.5Cu alloy) to maintain compliance and prevent joint degradation. SMD Components: