The past seven decades have not only seen Superman's powers dramatically increase, but also branch off into some rather startling, bizarre directions. In part one, we witnessed Superman projecting a beam of telepathic will control and, a few panels later, morphing into a completely different body shape! Obviously, those exotic new abilities never stuck...but there are plenty more weird new powers to catalog!
One of the weirdest appeared back in Superman #22 (1943). While in the process of rounding up the criminal gang of "Beetlebrow" Macklin, Superman employed some combination of his superpowers to broadcast his voice into police radios across Metropolis!
Now, long-time Superman fans might view this oddball power as a precursor to the equally silly super-ventriloquism power he used through much of the 50's and 60's. However, unlike that more direct, one-to-one form of long-distance communication, the super radio voice appeared to mass-communicate directly through radio waves. Or, more amazing yet, through a specific police radio frequency!
Some have postulated that all of these voice-projecting abilities could actually be psionic or mental in nature...unknown to even Superman himself. In other words, what Superman believes to be a long distance projection of his physical voice might actually be a mental projection of his thoughts to "listeners" he pictures in his mind...in this case the Metropolis police force.
That's the theory, anyway...one I don't really subscribe to. In fact, the psionic angle becomes kind of a Pandora's Box that leads to more "explanations" for Superman's scientifically impossible feats (such as flying, lifting buildings or ships without destroying them, etc), which tends to leach all of the fun and fancy out of the character.
Which may be the reason these strange "outlier" powers never really took root. While convenient to the plot, powers like super radio voice seemed to cross a subtle line that caused fans and even the creators themselves to think "Oh, come ON!". I mean, "powers and abilities far beyond those of mortal men" is one thing...but a super radio voice?