EMA was originally a part of the Ohio Adjutant General's Department (National Guard). As it is now part of the Department of Public Safety, the former EMA primary HF frequency of 4.64150 has been returned to AG's department. The others are part of the federal HF radio system and remain in use.
Frequencies
Ohio EMA
Ohio EMA Voice Channels
OEMA is in the process of de-commissioning the old VHF voice system. The replacement cost for narrow-banding was found to be excessive.