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At the risk of sounding ignorant to anyone with more knowledge of radio technology than myself: I recently purchased a radio-controlled alarm clock and was high
by mahathu 5y ago
At the risk of sounding ignorant to anyone with more knowledge of radio technology than myself: I recently purchased a radio-controlled alarm clock and was highly fascinated by how these devices get their time (and date) information accurately encoded through amplitudes and frequencies of radio waves from some radio antenna hundreds of kilometres away. I'm young enough to have grown up with the internet and have a decent understanding of the different network stacks in use today. But radio communications and their various applications is still such a fascinating topic to me!
- zh3 5y agoBecause of the long wavelength and high powers, the radio waves can be picked up pretty well by small ferrite aerials ('loopsticks'). In most cases, all the receiver has to do is detect the presence/absence of a signal; the transmissions start and stop every second, with variations in the starts and stops encoding the time (mostly it's necessary to receive a full 60s of transmissions, to get 60 bits of data that can be decoded to give the time). It's one of the easiest radio signals to pick up, a cardboard box with a few turns of wire around it and single transistor are enough in most of Europe.