When the planets approached a similarly cozy distance 94 years ago, in August 1924, some people, including Curtis D. Wilbur, the Secretary of the U.S. Navy, thought it might be possible to actually hear messages from our neighbor. If Martians were ever going to drop us a line, they suspected, that’d be the time.
From an office in Washington, D.C., Wilbur’s department sent orders to every naval station clear across the country. An outpost in Seattle received a telegram asking operators to keep their ears tuned to anything unusual or, maybe, otherworldly.
“Navy desires [sic] cooperate [sic] astronomers who believe [sic] possible that Mars may attempt communication by radio waves with this planet while they are near together,” it read. “All shore radio stations will especially note and report any electrical phenomenon [sic] unusual character …” The orders asked for operators to keep the lines open and carefully manned between August 21 and August 24, just in case.
Full article:
https://www.atlasobscura.com/articles/radio-signals-from-mars