MARS
| MARS | |
|---|---|
| Full name | Military Auxiliary Radio System |
| Sponsor | US Department of Defense |
| Current branches | Army MARS and Air Force MARS |
| Origins | 1925, with the Army Signal Corps |
| Operating | |
| Members | Volunteer licensed amateurs |
| Frequencies | Assigned military channels, mostly HF, outside the amateur bands |
| Modes | SSB voice and military-standard digital modes |
| Authority | Department of Defense, not FCC Part 97 |
| History | |
| Former name | Military Affiliate Radio System (1952–2009) |
| Navy-Marine Corps MARS | Closed in 2015 |
MARS, the Military Auxiliary Radio System, is a US Department of Defense program in which volunteer amateur radio operators support military communications, particularly when normal networks are disrupted. Members use their own stations and skills, but on MARS duty they transmit on assigned military channels outside the amateur bands, use separate MARS call signs, and operate under military authority rather than the FCC's amateur rules in Part 97. An amateur license is a requirement for joining, but MARS itself is not part of the amateur service. Two branches exist today, Army MARS and Air Force MARS.
History
MARS traces its history to 1925, when the Army Signal Corps began organizing amateur volunteers to support it and civil authorities in emergencies. The program was suspended during World War II and revived afterward, and in 1948 separate Army and Air Force programs were formed; the name Military Affiliate Radio System was adopted in 1952. A Navy-Marine Corps program followed in the early 1960s.
For decades MARS was best known for phone patches: MARS stations relayed radio calls from service members overseas, in remote posts and in Antarctica onto the telephone network, connecting them with their families, and passed short written messages called MARSgrams. Satellite telephones and the internet made most of that morale traffic unnecessary, and the program's focus shifted to contingency communications. The name became Military Auxiliary Radio System in 2009. The Navy-Marine Corps program was closed at the end of September 2015.
Mission today
MARS provides the Department of Defense with a volunteer HF radio network that works without the internet, satellites or the commercial telephone system. Its main jobs are:
- Contingency communications for the military services when normal networks are degraded, for example by a disaster or a cyberattack.
- Situational awareness in disasters: gathering reports from the affected area, including from ordinary amateur stations, and turning them into summaries for military planners supporting humanitarian relief.
- Exercises with military units and other agencies, some of which invite participation from the wider amateur community on the amateur bands.
Members of both branches usually operate from their home stations, take part in regular nets and exercises, and are expected to train all year.
Air Force MARS is an auxiliary program of Air Combat Command, based at Scott Air Force Base, Illinois, with about 500 volunteers in 2025. It runs HF phone patches for military aircraft when satellite radios fail, about 1,000 to 1,500 a year.
The best-known point of contact between MARS and ordinary hams is the Armed Forces Day crossband test, traditionally held around Armed Forces Day in May. Military and MARS stations transmit on their own frequencies and listen for amateurs on nearby amateur bands, giving hams with general-coverage receivers a chance to make two-way contacts with military stations. Such contacts between amateur and military stations are permitted under §97.111 of the FCC rules. The 2026 test was held on 9 May. Each military station announces the amateur frequencies it is monitoring, voice contacts use upper sideband, and a message is also broadcast in two military-standard digital modes, a serial-tone PSK mode and wide-shift RTTY, for listeners to copy. That year the US Naval Academy's club station, W3ADO, put the Navy's historic call sign NSS on the air from the grounds of a former Navy transmitting site in Annapolis, Maryland. Army MARS handles QSL requests, and the exercise has been held for more than 50 years.
Joining
Requirements are set by each branch and can change, so check with the branch before applying. According to the Army MARS website, applicants must be at least 18, a US citizen or lawful permanent resident, and hold an FCC amateur license of any class. They must sign a membership agreement and a non-disclosure agreement and pass a background check. To renew their membership, Army MARS members must log at least 72 hours of HF operation on Army MARS nets each calendar year and take part in at least one national-level exercise. Department of Defense policy requires all MARS members to be at least 18, a US citizen or lawful permanent resident, and hold a valid FCC amateur license, and Air Force MARS sets its own requirements on top of these.
Army MARS members are unpaid and supply their own stations. The branch requires an HF transceiver that can operate on all frequencies from 2 to 30 MHz with at least 100 watts of output, together with a computer, a modem and software for its military-standard voice and data modes. Many amateur transceivers need a modification to transmit outside the ham bands. A radio modified this way may be used outside the amateur bands only on assigned MARS channels and only for MARS business; on amateur frequencies the normal Part 97 rules still apply.
MARS and other emergency services
MARS differs from ARES and RACES, which use amateur frequencies to support civilian agencies such as county emergency management, hospitals and the Red Cross. MARS serves the military, on military frequencies. Many members belong to more than one of these organizations, and MARS exercises that collect reports from the amateur bands are one place where they meet. Like the other services, MARS falls under the broader umbrella of auxiliary communications described in AUXCOMM.