When digital switchover was complete, two new sub-bands of the UHF spectrum were clear (frequencies corresponding to channel ranges 31–40 and 63–69), leaving only channels 21–30 and 41–62 for digital television multiplexes. This "digital dividend" required millions of homes to upgrade their aerials to the wideband type to receive some or all of the Freeview multiplexes. This spectrum is useful because of its trade-off between bandwidth and range. Following a consultation, in September 2011 Ofcom stated that an auction for the 600 MHz band will most likely lead to channels 31–37 being used for three new TV multiplexes; a reference transmission plan assumes two frequencies would be multiple-frequency networks, and channel 36 would be used as a national single-frequency network. The remaining reallocated frequencies can be re-used for other services, for example the provision of: