What does LoRa look like?

Up close: a plain radio wave.

But its frequency slides,

low to high: a chirp.

Plot frequency against time

and each chirp is a diagonal,

four milliseconds long.

Every packet opens plain,

then down-chirps: the start.

Data chirps start mid-band

and wrap around the edge.

The start point is the data:

eight bits in every chirp.

Far away, noise buries it.

A receiver straightens them

and their energy piles up

into spikes above the noise.

Stretch the chirps longer

to hear ten times fainter:

slower, but farther.