Sonde balloon

A sonde balloon was a piece of equipment used to increase the range of communication devices. Consisting of a small balloon attached to a wire, it would lift communications equipment, such as an antenna, to an altitude that would enable it to clear ground-based obstacles. However, a sonde balloon is nondirectional, allowing anyone in the surrounding area to listen in if it is not encrypted.

While hiding from Imperial forces in the forests of Myrkr during the beginning of the Thrawn campaign in 9 ABY, Mara Jade and Luke Skywalker used a sonde balloon kept inside her survival kit to send an encrypted message back to Talon Karrde's nearby Myrkr Base. The high metallic content of trees native to Myrkr caused natural interference with sensors and communications equipment necessitating the use of a sonde balloon to rise above the forest canopy.

Text and facts from the “Sonde balloon” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.