I just want to get some clarifications regarding the transmission and receiving of a radio waves between planets as a means of communication with aliens for story building.
Is it better to transmit the signal from the surface of the earth or by placing any beacon or antenna in outer space? it is said that atmosphere has placed some limitations for sending messages.
Does a FM or AM radio wave transmitted to outer space gets dispersed while it propagates through outer space? lets consider that a message is transmitted to a planet of our nearest star. if disperses, can that signal be detected from any other planets of the same star?
To detect transmitted FM or AM signal from any other planets, do we need to point the telescope exactly towards that location? lets consider a radio signal being directed towards earth. let it be towards Arecibo Observatory. can we detect that signal from Arecibo telescope even if that telescope is pointed towards some other sources?
do we require big dishes or need the method of interferometry for detecting the radio signals or does the size of the telescope helps us to get better resolution of the detected radio signal?
THANK YOU FOR YOUR VALUABLE ANSWERS.