Nikola Tesla was convinced that radio waves could be used to communicate with
beings on other planets, especially that favorite of his era, Mars. He even tried it
several times, plus he also suggested using a series of flashing lights to communicate
with the Martians.

Tesla also believed he had picked up radio signals from ETI, but scientists
think he had detected what radio experts now call whistlers, low frequency
radio waves generated by lightning. He may have also inadvertently picked
up Jupiter's natural radio signals at times, which were not "officially"
recognized as such until 1955.

Articles online:

Corum, K. L., J. F. Corum, "The Electrical Signals of Planetary Origins

http://www.teslasociety.com/mars.pdf

Tesla, Nikola, "Talking with Planets". Collier's Weekly, February 19, 1901

http://earlyradiohistory.us/1901talk.htm

"The thought flashed through my mind that the disturbances I had observed
might be due to intelligent control . . . The feeling is constantly growing on me
that I had been the first to hear the greeting of one planet to another."

- Nikola Tesla, 1899

"I think that nothing can be more important that interplanetary communication.
It will certainly come some day and the certitude that there are other human
beings in the universe...will produce a magic effect on mankind."

http://roundtownufosociety.com/Book%20Reviews/tesla.htm

http://www.setileague.org/articles/mars1924.htm

http://instrumentationcolloquium.lbl.gov/Is_Anybody_Out_There.pdf

Plus there is a farside lunar crater and a planetoid named in his honor.