London 3

DAB ensemble · block 11B · 16 transmitters

Ensemble identifier: C199
Block: 11B
Frequency: 218.640 MHz
Licence: DL000026
Area: London
Services: 21 radio

On the map

Where London 3 is radiated from — 16 transmitters [V], Ofcom's published positions. This says nothing about how far the signal reaches; it is not a coverage map.

What it carries

Transmitters

16 transmitters, strongest first. TII is the transmitter identifier a receiver can report, which is how you tell which one you are actually hearing in a single-frequency network.
Transmitter	Nation	Block	Frequency	ERP	Height	Area	TII
Wrotham	England	11B	218.640 MHz	4.5 kW	150 m	North West Kent	08/0F
Croydon	England	11B	218.640 MHz	2.5 kW	128 m	London	0B/06
Epping Green	England	11B	218.640 MHz	1.0 kW	102 m	Hertfordshire	08/09
Bluebell Hill (S)	England	11B	218.640 MHz	900 W	41 m	London	0B/12
BT Tower	England	11B	218.640 MHz	800 W	192 m	Central London	08/17
Guildford	England	11B	218.640 MHz	782 W	39 m	London	0B/03
Alexandra Palace	England	11B	218.640 MHz	700 W	102 m	North London	0B/02
Chepping Wycombe	England	11B	218.640 MHz	600 W	50 m	London	03/16
Zouches Farm	England	11B	218.640 MHz	427 W	62 m	London	03/13
Reigate	England	11B	218.640 MHz	382 W	51 m	London	0B/05
Hemel Hempstead	England	11B	218.640 MHz	244 W	69 m	London	0B/07
Caterham Old Park Wood	England	11B	218.640 MHz	140 W	48 m	Caterham	08/0D
Pin Green	England	11B	218.640 MHz	60 W	28 m	Pin Green	0B/0C
Maidenhead Hyde Farm	England	11B	218.640 MHz	25 W	31 m	Maidenhead	08/05
Leatherhead Stoke dAbernon	England	11B	218.640 MHz	10 W	51 m	Leatherhead	08/12
Dartford Tunnel	England	11B	218.640 MHz	0 W	0 m	Dartford Tunnel

Radiation pattern

Its strongest transmitter with a published pattern, Wrotham. Other transmitters of this ensemble may shape their signal differently.

Radiates most strongly toward the west (290°), as published by Ofcom.

More detail

Each ring is 10 dB of attenuation below the pattern's own peak; the outer rim is the peak itself and anything 30 dB down or deeper is drawn at the centre rather than off the edge of the chart, so a very deep null reads as “weak” and not as a hole in the picture. The shape says which direction radiates harder relative to the mast's own peak, not the absolute field strength there or how far it reaches — that is what the coverage map and the postcode lookup are for.