[mech422]

I must be missing something ... Why broadcast speech over AM in an 'unmanned' tunnel ?? who's gonna hear/receive it ?? I wish the repo had some sort of use case summary or something...

Edit: I'm also sorta puzzled by the choice of AM in any sort of 'alert' context...Do people still listen to/use AM radios?

[anonymoosestdnt]

Updated the README with a use case section - vehicles with AM radios transit during construction/maintenance. Leaky feeder distributes the signal. Thanks for the feedback :)

[jacquesm]

AM radios are extremely simple and utterly fool proof, they can be made with only a handful of simple parts. Even so, these systems are archaic and these days you can make much more complex radio systems using a SDR which effectively reduces the whole radio to a pre-amp an ADC, an embedded CPU and some software.

[drweevil]

AM is a good modulation choice for low signal environments. It is used in the airbands for this reason.

[jacquesm]

Precisely, it degrades very gracefully, unlike FM or digital.