On: Software-Defined Radio for Engineers (2018) [pdf]

[mikewarot]

The transmitter has an electronically switched antenna that virtually moves in a circle at 3600 rpm, causing FM modulation phased with direction. The carrier is also AM modulated with a reference phase signal.

I built a gnu radio flowgraph to receive both and display heading to the VOR.

[mikewarot → mikewarot]

Sorry I was working from memory yesterday... It's 1800 rpm / 30 Hz, not 60.

https://en.wikipedia.org/wiki/VHF_omnidirectional_range

[pyinstallwoes → mikewarot]

Woah coming from a dsp / synth background that’s wild to hear.