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Can a pilot transmit and receive information at the same time? Or can he either transmit or receive but not at the same time?

I thought communication channels were half-duplex because this reduced the chance of the information by trasmitter (say the ATC) being overlapped by information from the receiver (the pilot) in case he possibily accidentaly pressed the PTT button. Is that a right assumption or not?

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  • $\begingroup$ They are half-duplex because all parties share the same frequency. Only one party can transmit at any time. Full duplex would require two frequencies. Can you edit your question to clarify if you don't understand this aspect of communication. $\endgroup$
    – Transistor
    Commented Jun 17, 2018 at 9:33
  • $\begingroup$ That is very clear, thanks. So the reason behind the channels being half-duplex lies in the fact that it would be necessary the use of two frequencies for the two parties to transmit and receive at same time. But was it the intention of non being able to transmit and receive at the same time wanted from the start because (as I said) that would potentially create confused situations? Or is that just a plain technical limitation as having two frequencies assigned per aircraft is just non convenient? $\endgroup$
    – aviation_geek
    Commented Jun 17, 2018 at 9:41
  • $\begingroup$ Full duplex would require two frequencies and therefore third parties would have to monitor both frequencies simultaneously in order to hear both sides of the conversation. Half-duplex operation on a single frequency is inherently 'open-channel' - everybody can hear everything transmitted by anybody else on that frequency. That's the way it's always been done in aviation and in many other fields. $\endgroup$
    – Fiddlesticks
    Commented Jun 17, 2018 at 10:41
  • $\begingroup$ Full duplex isn't unheard of though in aviation, there are some frequencies that are transmit only or receive only (like listening for an FSS over a VOR and transmitting on a separate frequency). $\endgroup$
    – Ron Beyer
    Commented Jun 17, 2018 at 16:15
  • $\begingroup$ @Fiddlesticks You should go ahead and make your comment an answer. They're trying to cut down on "answers in comments." $\endgroup$
    – TomMcW
    Commented Jun 17, 2018 at 16:47

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They are half-duplex because all parties share the same frequency. Only one party can transmit at any time.

Full duplex would require two frequencies and therefore third parties would have to monitor both frequencies simultaneously in order to hear both sides of the conversation. Half-duplex operation on a single frequency is inherently 'open-channel' - everybody can hear everything transmitted by anybody else on that frequency. That's the way it's always been done in aviation and in many other fields.

(Answer taken from comments by https://aviation.stackexchange.com/users/13124/transistor and https://aviation.stackexchange.com/users/15152/fiddlesticks)

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