Posted on November 25, 2010
A violent storm erupted here in the mid-waste, I mean, mid-west, last night, causing me to shut down KDX radio for protection from power interruptions. Tornado sirens had me positioned in the basement with emergency lighting handy, and a weather radio listening to NOAA at 162.550mHz. It was a good time for brain bending.
1. I wondered about antenna shape. The subject of fractal antennas has been well discussed and has to do with shaping an antenna. Here’s a good link
In some ways acoustics are comparable to electronics, e.g., speed of sound/light; resonant frequency; harmonics and overtones. So I thought of an interesting discovery of a few years ago I read about, regarding the shape of a bell. Traditional bells have a familiar flare-out-at-the bottom shape, which produces minor harmonics and over-tones, thus the “mournful” bell sound. But someone figured out that a bell flaring IN at the bottom produces MAJOR harmonics and overtones! A significant acoustic finding. Maybe a bell shaped antenna?
The only clue I can think of as to “what electricity looks like” is lightning, and that shape is always a fractal one, which brings us back to that.
2. In music it’s the harmonics and overtones that give each instrument its distinctive rich characteristic and therefore “high-fidelity” demands preservation of the wide-spectrum harmonics. But the opposite applies in radio transmission, where we only use the fundamental frequency and try to smother the uppers. BUT, imagine, say, a transmitter with the fundamental at 600kHz and a perfect well tuned 2nd-harmonic at 1200kHz, wouldn’t it be neat if entirely different programming could be modulated on each of the two carriers? Impossible? I wonder.