▁ 7 2 8 ▁den oting ▁the ▁dat ar ate ▁of ▁the ▁digital ▁s tere o ▁information ▁– ▁the ▁dat ar ate ▁was ▁ 7 2 8 k bit / s , ▁non - PC M . ▁ ▁Channel ▁alloc ations ▁ ▁The ▁ 6 2 5 ▁line ▁system ▁divided ▁the ▁spectrum ▁into ▁ 4 4 ▁channels , ▁ 2 1 – 3 4 ▁and ▁ 3 9 – 6 8 ▁( B ands ▁IV ▁and ▁V ). ▁These ▁channels ▁were ▁allocated , ▁by ▁the ▁G PO , ▁to ▁the ▁broad c aster s ▁to ▁allow ▁for ▁four ▁networks ▁to ▁operate ▁with ▁event ual ▁maximum ▁coverage ▁and ▁minimum ▁cross - network ▁inter ference . ▁The ▁two ▁BBC ▁channels ▁and ▁the ▁I TV ▁network ▁were ▁c ater ed ▁for , ▁as ▁well ▁as ▁space ▁for ▁a ▁future ▁fourth ▁network , ▁at ▁the ▁time ▁expected ▁to ▁be ▁a ▁second ▁network ▁for ▁the ▁I TA . ▁The ▁fourth ▁network ▁didn ' t ▁come ▁into ▁being ▁until ▁the ▁Broadcast ing ▁Act ▁ 1 9 8 0 ▁created ▁Channel ▁ 4 ▁and ▁S 4 C . ▁This ▁early ▁provision ▁meant ▁that ▁near ▁complete ▁coverage ▁was ▁afford ed ▁to ▁both ▁networks ▁at ▁launch , ▁in ▁ 1 9 8 2 . ▁ ▁When ▁Channel ▁ 5 ▁launched ▁in ▁ 1 9 9 7 ▁it ▁was ▁allocated ▁U H F ▁channels ▁which ▁were ▁in ▁use ▁by ▁many ▁domestic ▁V CR s , ▁requiring ▁a ▁massive ▁equipment ▁ret uning ▁exercise ▁to ▁be ▁undert aken ▁at ▁the ▁broad c aster ' s