The FM radio wave (Frequency Modulation) enabled transmitting and receiving a wider range of audio frequencies in a static-free environment, far surpassing the quality that AM radio provided (Amplitude Modulation).
That's about as deep into science I'm prepared to go at the moment because I'm more interested in telling you about Armstrong's quirkiness.
Armstrong had some bizarre habits and lived a life that ended tragically.
He adored radio towers and was prone to climbing them. One time he even climbed to the top of the 450-foot RCA radio tower on top of the RCA Building in New York City and stood on the very top - absolutely infuriating the head of RCA at the time, David Sarnoff.
But, there's a little more to this story. Armstrong had recently met Marion MacInnis who was employed as General Sarnoff's secretary. (The reason why people referred to Sarnoff as "General" is yet another story for another time.) Mr. Armstrong became infatuated with Miss MacInnis and devised a way to really get her attention.
That's where the RCA radio tower came in. Armstrong scaled the tower which was no easy feat. The tower was 115 feet high and was perched atop the 21 story Aeolian Hall in midtown Manhattan. Armstrong was careful not to climb to the apex without someone available to document his achievement.
And when I say "document", I don't mean to write about it. Edwin Armstrong arranged for someone to photograph his ascent to the very top. Once he reached the zenith, which was a hollow ball with a metal skeletal exterior, he mugged for the camera, did a little one-legged dance, sat with legs outstretched, and generally had a good time.
After he came down, Armstrong waited for his photographs to be developed and then sent copies of his prank to Miss MacInnis in the hopes she would realize what a catch he really was.
Needless to say, General Sarnoff was furious that anyone would breach the protocol of his glistening mast to perform such foolish stunts. The head of RCA immediately banned Armstrong from the building but Armstrong had the last laugh. He married MacInnis on December 1, 1923 and promptly went to Palm Beach, Florida for their honeymoon. As a wedding gift, he presented his new wife with the world's first "portable" radio which was enormous compared to the transistor radios and later years and the portable digital