M23 operates on many regular schedules and commonly changes ID’s. Sometimes it transmits on parallel frequencies. M23 has many variants, some of them very strange but all of them use a long zero. After 3/3/07 the call-up format changed to having 5 seconds between numbers and 12 seconds between call groups. M23 has been known to have long periods of inactivity.
Message Sample
Station Structure
ID (###) repeats, BT, Group Count (##)x2, BT, 5-figure single groups (#####), BT, IMI IMI, BT Repeat Group Count (##)x2, BT, Repeat Message, AR AR (or no ending)
Null Format: ID (###) repeats
Station Summary
Activity: Active
Emission Mode: ICW
Believed Country of Origin: West of Paris, France
Sources
