Aircraft Repeaters also operate on the primary and secondary repeater frequencies, and aircraft repeaters will always have special IDs transmitted with them. Aircraft will announce they have switched to repeater mode by transmitting the tactical callsign "HIGH BIRD" along with thier "CAPFLIGHT 45xx" callsign. CAP aircraft also use 122.9 and 123.1 MHz, AM, for air-to-air communications. Virginia Wing radio stations ID with "Jefferson" callsigns, with a two or three number suffix. Stations with callsigns "Jefferson 7xx" are CAP mobile stations. Stations with callsigns "Jefferson x00" (for example, "Jefferson 200" or "Jefferson 400") are group radio cache stations. During search and rescue operations, many stations will assume tactical callsigns, such as "Mission Base", "Ground Team Alpha" etc. Large search and rescue operations will usally see a repeater being used, another channel for simplex operations, and the aircraft channel, channel 4 (149.5375 MHz) being used also. Radios have Virginia State Police and Virginia Department of Emergency Management VHF-high band frequencies as well as National Park Service frequencies for communication with these agencies.