Amateur radio (by alaric)

The radio spectrum is a complicated and varied thing.

Although some people seem to separate "radio" from "microwaves", I tend to lump them together, so I'm going to consider "the radio spectrum" to be the section of the electromagnetic spectrum from the very lowest frequencies we can usefully use (a few Hertz) up to frequencies that we'd start to count as "infrared light" (several terahertz).

Those bounds are based on practicality - for very low frequencies, the antennas required to efficiently transmit become impractically large and the bandwidth available to communicate gets ridiculously low; at very high frequencies, our electronics cannot process the signals and we have to switch to optical methods, which is a whole different ballgame.

I'm going to give you a whirlwind tour of the radio spectrum - but with an agenda: I'm just setting the scene so I can talk to you about amateur radio... Read more »