The ITU (International Telecommunication Union) decided that. They developed a standard which can be found here
Bonus question : Why a channel rather than a frequency ? I have no idea how to set my radion on channel 16, but I can most likely listen or even talk on the maritime band with my free-flight radio (which technically is an unlocked VHF-UHF transmiter) Obvious note that I stay on the allocated frequencies for free-flight or the PMR-446 band and never use the HAM band
under the hood it is a frequency, it’s standardized by ITU
I believe this is for ease of use. When using HF or MF you have to set the frequency yourself. That is a level above The required SRC - short range certificate needed for a VHF.
The frequency is 156.8mhz. The documentation gives both.
“Because” or “Shut up that’s why” (that’s my favorite “because”)
It is. We had to decide on a standard distress channel. That’s it.
