Simple illustration of how the observed radio frequency pattern changes as the star–planet system rotates, assuming a dipolar, axisymmetric magnetic field. We show the frequency pattern as seen from an observer located at mid-to-high magnetic latitudes from the star system. The planet is shown moving from positions 1 to 3. It appears larger when it is closer to the observer (position 2), and the same perspective effect applies to the radio beam cones. Colored cones indicate the radio emission directed toward the observer: blue-yellow (top-bottom), green-red (right-left), and gray indicates directions with no emission toward the observer (represented by the eye symbol). As the planet orbits, different portions of the emission cone become visible to the observer, leading to changes in the observed frequency pattern. The magnetic field line is shown in magenta color. The illustration is not to scale.