Just like on Earth, where some radio waves can travel around the
horizon, radio waves on Saturn can also do that.

"Cassini's radio plasma wave instrument detects the storm every time it
rotates into view, which happens every 10 hours and 40 minutes, the
approximate length of a Saturn day. Every few seconds the storm gives
off a radio pulse lasting for about a tenth of a second, which is
typical of lightning bolts and other electrical discharges. These
radio
waves are detected even when the storm is over the horizon as viewed
from Cassini, a result of the bending of radio waves by the planet's
atmosphere."

Ring planet DX anyone? :-)