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https://axleos.com/building-a-gps-receiver-part-1-hearing-whispers/
I decided to try my hand at decoding these GPS signals, guided by the vague end-goal of plucking out my position from peanuts. I learned that the GPS signals that facilitate our mapping apps are ever-present, around us at any altitude, in any weather conditions, at all times.
This sounds cool in the abstract, but the tangible reality is staggering. These signals are all around me as I write this. They're all around you as you read it. The world is soaked in these whispers, repeating themselves endlessly for anyone willing to listen.
You can find out exactly where you are, from thin air, anywhere at any time, by learning to speak the language of the electromagnetic waves flowing over your skin. These waves have been a constant and quiet companion for most people's entire lives.
[...] All that said, it's not as though there's a cacophony of navigation data swarming around you, deafening if you could just hear it. In reality, the GPS signals surrounding you are astoundingly weak. To take an analogy: imagine a normal light bulb, like the one that might be above you now. Pull it twenty thousand kilometers away from the room you're in, and have it flash, on, off, on, off, a million times a second. Imagine straining your eye to watch the shimmer of the bulb, two Earths away, and listen to what it's telling you.
[Ed's Comment: Links to subsequent parts of this series are included in the source article]
(Score: 0) by Anonymous Coward on Wednesday April 17, @02:35PM (7 children)
Transistors...bah humbug!
We had to make all our RF circuits with vacuum tubes!
(Score: 3, Funny) by JoeMerchant on Wednesday April 17, @02:48PM
How many vacuum tubes for a single GPS receiver channel?
🌻🌻 [google.com]
(Score: 5, Informative) by Anonymous Coward on Wednesday April 17, @03:18PM (2 children)
You don't need tubes or transistors to build a radio! When I was a kid building crystal radio receivers was a common project in electronics, which use only a diode.
If you ever wondered why these were called "crystal radios", well, that was because in the very early days of radio the diode itself was something called a "cat's whisker." To build one of these, you take a literal crystal of a semiconductor material (such as galena, which is a natural occuring ore), and then touch it with a very sharp metal point (e.g., a thin wire -- hence the name cat's whisker).
This actually forms a metal-semiconductor junction (like a schottky diode) and is the origin of the diode's schematic symbol.
(Score: 1, Funny) by Anonymous Coward on Wednesday April 17, @04:01PM (1 child)
Cat's whisker...bah humbug!
We used to make our radios with tiger's whiskers - and that tiger was none to pleased about it!
(Score: 1) by khallow on Friday April 19, @03:52PM
Indeed. Things got a lot easier once we realized the sharp point goes in the cat.
(Score: 3, Funny) by Tork on Wednesday April 17, @05:35PM (1 child)
🏳️🌈 Proud Ally 🏳️🌈
(Score: 3, Funny) by DannyB on Wednesday April 17, @06:48PM
Wut's dis? You didn't use the Cap'n Crunch Whistles [telephone-museum.org] to avoid paying for long distance?
When trying to solve a problem don't ask who suffers from the problem, ask who profits from the problem.
(Score: 2) by driverless on Friday April 19, @02:21AM
Meh, when I were a lad we had to locate the North Star and then hold up sticks tied into a cross shape to correct for position.
Anyway, haven't got time to stand around chatting, need to start banging the rocks together to start the fire for dinner.