CNN CNN Newsroom March 11, 2014 18:14:00
Radar is kind of like the polo to the marco. when primary radar is out looking, it can say hey, i see something out there. but until you get the polo back, which is the transponder telling you here's who i am, here's where i am, that's the secondary information that's missing. so from the cockpit, you can turn that off. what you can't turn off is the primary radar, which is going to tell you there is something out there. so i think with the search, you're right, it's a huge area where it could go. but if this information is krek correct, it's very significant indeed and would really narrow tha...
Source: archive.org