From ARRL.org:
The US Department of Defense (DoD) will host this year’s Armed Forces Day (AFD) Crossband Test on May 13, 2023. This annual event is open to all licensed amateur radio operators and will not impact any public or private communications. For more than 50 years, military and amateur stations have taken part in this event.
The AFD Crossband Test is a unique opportunity to test two-way communications between military communicators and radio stations in the Amateur Radio Service (ARS), as authorized in 47 CFR 97.111. These tests provide opportunities and challenges for radio operators to demonstrate individual technical skills in a tightly controlled exercise scenario.
Military stations will transmit on selected frequencies and will announce the specific ARS frequencies monitored. All of the times are Zulu (Z), and all frequencies are Upper Side Band (USB) unless otherwise noted. The frequencies used for the test will not stray outside the confines of the exercise.
A complete list of frequencies, time periods, QSL cards, and other information can be found at DoD MARS – Armed Forces Day.
AFD is a time of honor. It will be celebrated on Saturday, May 20, 2023. The first AFD was celebrated with parades, open houses, receptions, and air shows. Today, many events and activities take place and may include multi-service military displays in areas open to the public, various educational activities that teach children about the armed forces, and large parades with local celebrations.
The longest running AFD parade in the United States is held in Chattanooga, Tennessee. Certain types of music will be played at AFD 2023 events to show respect to those in the armed forces who died for their country.