| Abbreviation | Definition |
|---|---|
| AREC | Amateur Radio Emergency Communications |
| AREN | Amateur Radio Emergency Network |
| ARES | Amateur Radio Emergency Service |
| ARES | Amateur Radio Emergency Services |
| ARF | Amateur Radio Forum |
| ARFCN | Absolute Radio Frequency Channel Number |
| ARHAB | Amateur Radio High Altitude Ballooning |
| ARKB | Amateur Radio Kota Bharu |
| ARLOY | Amateur Radio Lady Of the Year |
| ARO | Amateur Radio Operator |
| ARO | Austin Repeater Organization |
| AROS | Amateur Radio Observation Service |
| ARPS | Amateur Radio Packet System |
| ARRG | Amateur Radio Repeater Geezers |
| ARRL | American Radio Relay League |
| ASAP | Area, Speed, And Power |
| ASCP | Amateur Station Control Protocol |
| ASDIC | Anti-Submarine Detection Investigation Committee |
| ATT | At This Time |
| ATV | Amateur Television |