No one is able to answer me !
Does anyone know the default broadcast format?

It's worrying.

Hello, I start with the esp32 with the Arduino framework. I try station mode with no problem and access point mode, both modes taking examples. I have a problem with AP mode: I'm testing transmission with a smartphone application: Wifi Analyzer. While all the Wifi broadcasts around me are 22MHz band...

Have a look :
https://community.platformio.org/t/noob ... de/19117/5

You have to add this two lines to platformio.ini :
monitor_rts = 0
monitor_dtr = 0

You can also go to :
https://docs.platformio.org/en/latest/p ... onitor-rts