Any aliens who decided to check us out would have to have originated within about 67 light years from us, because the first radio transmission was sent in 1897. That's assuming aliens would be limited to light speed...and also assuming they'd be capable of light speed. There aren't many star systems within that distance, and the odds of the ones that are being conducive to intelligent life are...well... astronomical.
I suppose it's possible someone was just passing by, exploring the Milky Way, and stumbled upon Earth at just the right time to catch us shortly after the industrial revolution, when things might be slightly interesting to them, but that seems unlikely, concerning the vast expanse of the galaxy.