SG teams maintain radio contact with each other while off-world using radios which fit into the upper left breast pocket of the SG vest. The radios can also be fitted with earpieces that are worn in the left ear, used most frequently during the third year of SG missions. The radios can have a significant range on a planet's surface and can maintain contact between a planet and a ship in orbit, although they do not reliably transmit from deep underground. While off-world, a team can maintain radio contact with the SGC by using the relay antenna of the MALP or UAV to relay the radio signal through an open wormhole for live two-way audio communication. The radios are also equipped with an RDF (radio direction finding) signal that can be used to determine the location of another radio transmission. In radio transmissions, the designation "niner," for example "SG-1 niner," refers to the commanding officer of the given SG unit.
First Introduced: Children of the Gods