The annual celebration is a unique opportunity to test two-way communication between radio amateurs and military stations (authorised under Part 97.111 of the Amateur Service rules). It features traditional military-to-amateur crossband SSB voice, CW, practice using legacy interoperability waveforms, and the opportunity for participating hams to utilise more modern military modes, such as MIL-STD Serial PSK and Automatic Link Establishment (ALE). Military stations and Amateur Radio stations are authorised to communicate directly on certain 60-meter interoperability channels - 5,330.5, 5346.5, and 5,371.5 kHz.
These tests give Amateur Radio operators and shortwave listeners a chance and a challenge to demonstrate individual technical skills and to receive recognition from the appropriate military radio station. QSL cards will be available for stations successfully contacting participating military stations.
The Armed Forces Day message will be transmitted via Military Standard radio teletype modes (MIL-STD 188-110A/B).
Software is available to demodulate the military serial PSK waveform, and detailed instructions can be downloaded - http://www.n2ckh.com/MARS_ALE_FORUM/MSDMT.html
Utilising this mode with sound card equipment can be challenging; review the instructions carefully.
A short practice transmission will be sent at 1930 and 2330 on 6, 7, 10 May 2017 and 12 May on 13.506.5 MHz USB and 17.443.0 MHz USB.
Military FSK is Baudot at 850 Hz, 75 baud, low mark, and 2000 Hz centre. Most RTTY programs can be set to decode this mode. To achieve low mark while receiving in USB, select reverse shift.
QSL cards are available for individuals that receive the Armed Forces Day test message. To receive a card, copy the printed text of the test message as received from the military station, and include it in your report. No attempt should be made to correct possible errors.
Stations copying Armed Forces Day messages transmitted from US Army and US Navy stations and requesting a QSL card, can complete the QSL report form online - http://www.usarmymars.org/
Stations copying the Armed Forces Day message transmitted from US Air Force stations and seeking a QSL card should send a request to Armed Forces Day Celebration, Chief, Air Force MARS, 203 W. Losey St, Scott AFB, IL 62225.
Include a transcript of the received text, time observed, frequency observed, military station call sign, your full name and Amateur Radio call sign (if applicable), full mailing address (including ZIP code).
Stations with Automatic Link Establishment (ALE) capability can contact a military station on specific half duplex cross band channels established for this purpose. ALE is a selective calling and linking method utilised by the government, military, and amateur radio communications.
Military stations will scan and receive certain amateur HFLINK ALE frequencies and transmit on the corresponding military ALE frequency. Military stations will also transmit ALE station identification (soundings) on each military frequency at 30- to 90-minute intervals.
Amateur stations may scan military frequencies and monitor the soundings to build the LQA database or select the channel manually. Amateur stations will call military stations using ALE selective calling on one of the paired cross band channels.
Complete information, including military stations, modes, and frequencies, is available on the US Army MARS website - http://www.usarmymars.org/home/announcements
