| Abbreviation | Definition |
|---|---|
| MARM | Manitoba Amateur Radio Museum |
| MBARC | Mount Baker Amateur Radio Club |
| MBARC | Mt Baker Amateur Radio Club |
| MBARC | Mt Beacon Amateur Radio Club |
| MBX | Multi-Band Transmitter |
| MC | Master of Ceremonies |
| MDT | Modulated Data Transfer |
| MEA | Multi-Element Antenna |
| MM | Maritime Mobile |
| MOPA | Master Oscillator, Power Amplifier |
| MPT | Manner, Place, Time |
| MRC | Milwaukee Repeater Club |
| MRC | Mobile Range Communications |
| MRRC | Mad River Radio Club |
| MRRL | Michigan Radio Relay League |
| MS | Mobile Station |
| MSNBC | Mars Society News Broadcasting Channel |
| MSUARC | Michigan State University Amateur Radio Club |
| MSWR | Modified Standing Wave Ratio |
| MTN | Michigan Traffic Network |