37.5hZ

[nyazzip]

...i learned today that the blackbox ping from a downed airliner is +_40hZ....much lower than i wouldhave thought. i understand low fq would travel greater distances, but it also takes much more power to transmit...anyone know how the black box produces a pulse? just curious

[Geek]

37.5 KHz

Must have been a typo on your news site.

[nyazzip]

yes, i went back to the article before i posted to verify and it said hertz, not kilohertz...they were wrong. thanks

[Geek]

...anyone know how the black box produces a pulse? just curious

I have an old US Navy training book with early black box designs. Simply put, think of an electronic clock. Only instead of the pulse driving a solenoid, it drives an electromechanical resonator. Low parts, silly simple, outrageously reliable.