Viewers in Derby will, from 5th October 2011 are able to watch Freeview HD for the first time from the mast located in the city.
In addition, the D3+4 service moves from C30 to C51, so you will need to do a "full retune" to get all of the Freeview Light services.
Most homes in Derby using this relay transmitter should also be able to pick up the commercial multiplexes from the Sutton Coldfield transmitter - and also pick up the "West Midlands" version of BBC One and ITV1.
Just north of Derby at Belper and Stanton Moor, the BBCB multiplex (that carries Freeview HD) will move from C65 to C55. If you use Freeview HD from these two transmitters, you will also need to retune on 5th October.