Retain the original carrier feature from PR #11 with zero-deviation FSK, board PA calibration, and LoRa restoration. Re-key after power changes without extending the timeout, and restore prior power after a failed sweep. Cover native and SX1276 transitions, failure recovery, external PA and RFO mapping; verify Linkflow repeater and Heltec V2 USB Companion builds.
Support fractional seconds, guard active packet work, keep the MCU awake, and restore reception after carrier tests. Include regression coverage and independent-radio RF validation for the V4 and T1000-E.
mikecarper