I think the same way as usual, but due to very narrow beams of modern systems, they are hard to be detected by someone else than a targeted plane (also acts as a partial HARM immunity).
Modulation and other RF properties are the same.
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You just move the beam like you would move the whole antenna (or feeder) in a "classical" non-phased system.
Last edited by Alien_MasterMynd; 07/15/15 07:40 PM.