  In this paper, we test the possibility that the structure of the largest
radio galaxy J1420-0545 may have been formed by restarted rather than primary
jet activity. This hypothesis was motivated by the unusual morphological
properties of the source consisting of two edge-brightened, narrow, highly
collinear, and symmetric lobes, thus suggesting an almost ballistic propagation
of powerful jets into a particularly low-density external medium. New
observations made with the VLA together with the currently available GLEAM and
TGSS ADR1 data releases allow the detection of an excess emission at low
frequencies. An extracted part (88 MHz - 200 MHz) of the spectrum of the
emission is fitted with the DYNAGE model, giving a forecast for the
environmental conditions and the energetic requirements for the presumed old
cocoon related to a preceding epoch of jet activity.
