Complex sentence: It is broadcast around the clock on DAB and web radio; also (evenings and overnight only) on FM--since 1 November 2011 P2 has timeshared its FM frequencies with P1.
Split into simpler sentences: It is broadcast around the clock on DAB and web radio; also (evenings and overnight only) on FM. Since 1 November 2011, P2 has timeshared its FM frequencies with P1.