Llanarmon Yn Ial
Wales · TV
Position 53.114867, -3.205648 Grid reference SJ19405820 Nation Wales Ground height 346 m Antenna height 18 m Aerial group Group A — C21–37, the low end of the band Polarisation Vertical BBC region Wales ITV region Wales ITV news region Wales Parent transmitter Moel y Parc Ofcom site number 14517 The position is our conversion of Ofcom's grid reference SJ19405820 from OSGB36 to WGS84 [V] . Ofcom publish no latitude and longitude for television sites. The transform is verified rather than assumed: on the 3,403 radio records that carry both, it reproduces Ofcom's own coordinates to within 0.1 m. OpenStreetMap has a mast 94 m away, matched on a name match [V] . That is an independent check on the position, not a correction to it — see how positions were checked .
How far it reaches The share of the UK's 238,895 Census Output Areas where this mast is the strongest signal of its kind. Not the share it reaches at all — most places can receive several transmitters, and only one of them can be the best.
This is a share of areas, deliberately, and not a number of homes. Checked against Ofcom's own published coverage, this model gets the ranking of transmitters right (Spearman 0.861) and over-states how far each one gets by a median factor of 2.5. A share is a ranking statement and survives that; a household count would not, so there isn't one. How this is worked out .
On the map
Where Llanarmon Yn Ial is the strongest signal for television.
Television This site carries the three public-service multiplexes and none of the three commercial ones, which is the normal arrangement at a relay — 1,059 of 1,169 sites are like this. Channels on SDN, ARQ A and ARQ B are simply not transmitted here, and no aerial will recover them; they need a main station. PSB3 (BBC B) is the UK's only DVB-T2 multiplex and carries every HD channel. Losing the HD channels while keeping the rest is therefore a single-multiplex fault rather than an aerial problem.
Transmitter data is Ofcom's; every dataset and the terms it is used under are listed under sources . Coverage figures are modelled, not measured, and are systematically optimistic .