Aviation transponder

A transponder comprising:

• at least one antenna port;
• at least one controller;
• a local oscillator configured to generate a radio signal at a first frequency;
• a first switch coupled to the local oscillator and configured to selectively couple the local oscillator to a transmit path or a receive path;
• and
• a second switch coupled to an antenna path and configured to selectively couple the antenna path to the transmit path or to the receive path;
• wherein the at least one controller is configured to, at a first time:
• cause the first switch to couple the local oscillator to at least a portion of the receive path;
• cause the second switch to couple the receive path to the antenna path;
• and
• receive an interrogation signal via the at least one antenna port;
• and
• wherein the at least one controller is configured to, at a second time after the first time:
• enable at least one transmit amplifier associated with the transmit path;
• cause the first switch to couple the local oscillator to the transmit path;
• cause the second switch to couple the transmit path to the antenna path;
• and
• cause the at least one antenna port to output an identification signal at least partially in response to receiving the interrogation signal.

A method comprising:

• causing, by at least one controller of a transponder, and at a first time, a first switch to couple a local oscillator to at least a portion of a receive path of the transponder;
• causing, by the at least one controller, a second switch to couple the receive path to an antenna path of the transponder;
• receiving an interrogation signal via at least one antenna port;
• enabling, by the at least one controller, at least one transmit amplifier associated with a transmit path;
• causing, by the at least one controller, and at a second time that is different than the first time, the first switch to couple the local oscillator to the transmit path;
• causing, by the at least one controller, the second switch to couple the transmit path to the antenna path;
• and
• causing, by the at least one controller, at least one antenna port to output an identification signal at least partially in response to receiving the interrogation signal.