2 trucks long truck 2 cars I94 near K 154.6550 . raido problems "switch to the marks channel" ?
To further what Hazmat34 has already stated. MARC frequencies are valuable when an incident requires multiple agencies (fire departments, police departments, flight for life, ALS ambulances, highway department) to respond that normally don't work together.
For example.... This sounds like a crash on I-94 requiring a fire department, state patrol, police department and highway department to respond. All of theses agencies have their own radio frequencies they use. However, to maintain communications when all agencies are working on the same incident, the state mandates all radios are programmed with MARC frequencies. The incident commander can then request all units go to MARC channel 1, all radios in the fire trucks, police cars, highway department vehicles will be programmed properly and able to communicate.
If the state didn't have MARC frequencies, agencies on the same incident scene could not communicate and would be trying to relay stuff back-and-forth, obviously not the most ideal.
Here are some to get you started....
MARC 1 - 151.2800
MARC 3 - 154.0100
MARC 4 - 154.1300
WISPERN - 155.4750
Point-to-Point - 155.3700
Little known fact, about 90% of Wisconsin is covered by repeaters on MARC frequencies in-case of large scale disasters that require repeaters to aid in communication. These systems were funded by the government pouring money into homeland security. It could be simplex, or repeater operations on MARC freqs.