In the 1980s we downloaded games from the radio

My brain is unable to grasp it..How does it work and at what speed things used to get downloaded?

Regular audio cassettes were also used as storage medium for software. Distributing over radio just mean playing these tapes. And people could then record the broadcast at home and load the software from cassette.

This is the “loading” of the classic ZX Spectrum computer game Manic Miner coded by programming genius Mathew Smith. The data is converted into audio and sold on cassette tapes. Instead of a disk drive, you would plug in an audio cassette tape player into the ZX Spectrum computer and “play” the sound into the computer, which would then read this audio as data and use it to load the game into memory, after which it could then be played. So instead of distributing the audio as cassette, in this case that same audio is broadcast over the radio and people would record it from the radio onto a cassette tape. Then playing the cassette into the computer would load (“download”) the game into the machine. Primitive but it works, and what we had to put up with.

Imagine being six years old and wanting to play Manic Miner, and having to sit there for 6 minutes while your TV did this before you could play the game:

https://youtu.be/kHn_BvTBALI?si=5CrKYa6DlNZTN7In

(Please watch in full without doing anything else or scrolling for the authentic experience)

More or less just like Wi-Fi.

Your wi-fi access point takes electrical signals coming from something else, like a router, and turns them into radio waves that are captured by the antenna on your phone or computer. This is, then, fed to the Wi-Fi controller on your phone or computer which translates these transmissions back into electrical signals.

Loads of math are involved in getting it right, but that's the gist of it.

The data is encoded in subtle shifts in the frequency. This is a type of modulation. Look up https://en.wikipedia.org/wiki/Signal_modulation and https://en.wikipedia.org/wiki/Frequency-shift_keying

This series of videos walks through building a circuit to decode one type of audio data format that was used in the 80s and send data to a computer and discusses how the audio signal works and simple circuit to turn it into digital data https://www.gregorystrike.com/2023/01/07/kansas-city-standar...

(I just got another one of these kits because I had previously built, successfully tested, then threw it out after I had some issues using it as-is, but I want to build it again with the additional electronics experience I have now.)