The majority of TV transmitters/relays in Ireland and the UK have been assigned one of the following 10 sets of 4 UHF channel groups (see below). In Ireland most transmitters follow this pattern, with some exceptions, including Three Rock, Kippure.
It is obvious that transmitters/relays where RTE1 and NET2 are broadcast on VHF have two spare assigned UHF channels (after TV3 and TG4 are taken into account).
However the 2 spare channels may in the future be used for:
(A) A move of RTE1 and NET2 to UHF (This has already happened at some RTE relays which were previously VHF)
or:
(B) may instead be reserved for future high power digital TV services
1: 21,24,27,31 (Aerial Group A) i.e. Mullaghanish 2: 22,25,28,32 (Aerial group A) 3: 23,26,29,33 (Aerial Group A) i.e. Holywell Hill 4: 39,42,45,49 (Aerial Group B) 5: 40,43,46,50 (Aerial Group B) i.e. Cairn Hill 6: 41,44,47,51 (Aerial Group B) 7: 52,56,66,68 (Aerial Group C/D) i.e. Clermont Carn, Maghera 8: 53,57,60,63 (Aerial Group C/D) i.e. Spur Hill, Truskmore 9: 54,58,61,64 (Aerial Group C/D) 10: 55,59,62,65 (Aerial Group C/D)