The sub-reflector of an antenna

The sub-reflector of an antenna, or secondary reflector, is the structure in charge of concentrating the signals received by the main dish (parabolic primary reflector) and directing them towards the receivers in charge of converting the analog signal into a digital signal. Sometimes it is necessary to repair them on-site under extreme weather conditions. © Juan Carlos Rojas - ALMA (ESO / NAOJ / NRAO)