Retuning Advice for Customers
The band width which is used to transmit Television Channels ranges from 21 to 69.Before Switch over one Television Channel would be transmitted on one channel number.
Analogue Example from the Tunbridge Wells (Pembury) Transmitter.
BBC1 =Ch51, BBC2=Ch44, ITV1=Ch41, Ch4=Ch47, Ch5=Ch37.
Digital enables a group of channels to be transmitted on one channel number. The group of channels which are transmitted together are called a Multiplex, (mux).The Main Transmitter transmits SIX multiplexes.
The Relay Transmitters transmit only three multiplexes so offering a less channels; which I think the term they will use is they offer a ‘LIGHT’ service.
Automatic Tuning starts tuning from Ch21 up to Ch69.
The problems with this Auto Tuning is some equipment will lock into the wrong transmitter as it tunes into which ever channel it finds first, which may not be the Transmitter the Aerial is aligned to.
Customer has aerial pointing towards Tunbridge Wells (Pembury) and the house is on Bidborough Ridge. The Mux channel numbers for:-
Crystal Palace are 23,26,30,25,22,28.
The Mux channel numbers for:-
Pembury are 52,49,47,42,44,41.
Therefore in this example some equipment will tune into Crystal Palace, with enough signal to lock in; but not enough to give constant good reception.
Manual tuning overcomes this problem as some equipment can have the correct channel numbers entered directly, which correspond to the Transmitter the aerial is aligned to.
When tuning the equipment it is advisable to clear the existing memory on the tuner by doing a factory reset or doing an automatic tune with no aerial attached.
For Additional Help Check out http://www.digitaluk.co.uk/how_do_i_switch/connections__and__retuning/retuning_instructions