UKCemaes
Wales · TV
- Position
- 53.405068, -4.448939
- Grid reference
- SH37309260
- Nation
- Wales
- Ground height
- 40 m
- Antenna height
- 16 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
- Llanddona
- Ofcom site number
- 11811
How far it reaches
Two different questions, and the map below can be switched between them. Reaches is everywhere this mast puts a usable signal; strongest is the much smaller slice where nothing else does it better.
| Band | Reaches | Strongest in | |
|---|---|---|---|
| Television | 18 of 238,895 Output Areas | under 0.1% of UK Output Areas | a relay, serving a local area |
More detail
Most places can receive several transmitters — a median Output Area hears twelve — and only one of them can be the best, which is why the two columns are so far apart. Reach counts an area once the model clears the reception threshold there at all, and it inherits the sweep's screen: only the strongest twenty candidates per area are stored, so a mast lying twenty-first somewhere does not count as reaching it. Both are a share of areas, deliberately, and not a number of homes: checked against Ofcom's own coverage the model ranks transmitters correctly (Spearman 0.861) but 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. How this is worked out.
On the map
Everywhere Cemaes is predicted to reach for television, shaded by how much signal is left over. Other transmitters reach most of this ground too.
Only the areas where Cemaes is the strongest option for television — the ones the postcode lookup would send here. A smaller picture than its reach, and a different question.
The lines are how far the signal is modelled to get: solid while the margin still clears 10 dB, dashed out to where it last clears 0 dB. The real edge sits inside them — every point inherits the model's measured optimism of about 17 dB.
How the rings were drawn
It is an envelope, not a boundary: terrain can still block reception well inside it, and it is an edge, not a fill — the colour says how far the signal gets, not that every spot under it works. Zoom in and the shading gives way to the per-area prediction, which is the same question answered Output Area by Output Area. The television ring was contoured from the stored predictions, which keep only the strongest candidates for each area — the true edge can extend beyond what is drawn [I].
The modelled outer edge drawn above: television about 10 km toward the east but barely beyond the mast toward the north [I].
Open this transmitter on the full mapreach, the aerial direction, and everything else within range
Television
| Mux | Freeview name | Channel | Frequency | ERP | System | Operator |
|---|---|---|---|---|---|---|
| PSB1 | BBC A | C32 | 562 MHz | 25 W | DVB-T | BBC |
| PSB2 | D3&4 | C34 | 578 MHz | 25 W | DVB-T | Digital 3&4 (ITV/Channel 4) |
| PSB3 | BBC B | C35 | 586 MHz | 25 W | DVB-T2 | BBC |
Other transmitters nearby
Every structure Ofcom list within 40 km, nearest first. Close is not the same as an alternative: most of these are single-service relays, and one of them may radiate a thousandth of this mast's power in a direction that misses you.