Divis transmitting station

Divis

Divis transmitting station (Northern Ireland)
Location	Hannahstown,County Antrim
Mast height	140.7 metres (462 ft)
Coordinates	54.6075°N 6.009444°W/54.6075; -6.009444
Grid reference	NW4111830995
BBC region	BBC Northern Ireland
ITV region	UTV
Local TV service	NVTV

Transmitter in 2007

Divis transmitting stationis the main high-power UHF and BBC National FM/DAB station that servesCounty Antrimand parts ofCounty Down.

History

Situated just outside Belfast, it is the primary UHF/FM main station inNorthern Irelandand was originally Northern Ireland's main BBC 405-line television transmitter, coming into operation in this capacity on 21 July 1955. As such, it was the first permanent television transmitter to be established within the island of Ireland. It was built byJ. L. Eve Construction,which also built the similar-heightMeldrum transmitting stationfor north-east Scotland, at the same time.

Although one of three UHF main stations in Northern Ireland, it is the only one to feature a stayed mast; the other stations atBrougher MountainandLimavadyboth utilising smaller self-supporting towers. Stayed masts are however located at the UHF relay stations at Derry andStrabane(respectively former BBC and ITA405-linerelays) and at Black Mountain, the former ITA 405-line (and Channel 5) main station sited adjacent to Divis. It is owned and operated byArqiva.

The Divis station is located in a range of hills directly overlooking Belfast from the west, in an area which was controlled by theMinistry of Defenceuntil it was sold in 2004 to theNational Trustand subsequently opened to the public. It is sited between the peaks of Divis Mountain and Black Mountain and is ironically closer to the latter than the transmitter that is named after it.

Television history

Divis was opened by the BBC on 21 July 1955 as its permanent 405-line Band I transmission facility serving Northern Ireland. It superseded the temporary station atGlencairn,which was one of two transmitters (the other beingPontop Pike) to be rushed into operation on 1 May 1953, in time for the televised Coronation ofQueen Elizabeth II.Although the BBC had by this time already obtained the Divis site, the need to construct the long access road was the primary factor preventing its immediate use.

Divis was designated as a medium-power transmitter, on which type of installation the second phase of BBC Band I stations were based. In this respect, Divis was grouped with permanent installations atMeldrum,North Hessary Tor,Pontop Pike,Rowridge,SandaleandTacolneston.Transmissions from Divis were on VHF Channel 1 at a peak output of 35 kW vision e.r.p.

In due course, a number of relay stations were established across Northern Ireland to enhance coverage from Divis, most notably at Derry’sSheriff's Mountaintransmitter which opened in December 1957, andBrougher Mountainin County Fermanagh which opened in February 1964, the latter being the site of a future UHF main station.

In the meantime, theIndependent Television Authority(ITA) built its equivalent 405-line VHF Band III station close to Divis. Located atBlack Mountainquarry, less than two miles to the south-west, this came into operation on 31 October 1959 and utilised a taller 750-ft mast.

Divis became the UHF main station for Belfast and the surrounding area withBBC2being the first regular service commencing on 18 March 1967. Colour UHF transmitters for BBC1 and ITV came into operation in September 1970.

Both this site and Black Mountain are dual ring-fenced for security.

It was announced that the 152.5m transmitter mast at Divis would be removed and replaced by a new guyed steel mast (192.7 m). This meant for a period of time there would be two broadcast masts at the site in preparation for the digital switchover in the Ulster region which occurred in October 2012. However a new 152m guyed mast has been constructed and the original mast remains to carry VHF and DAB services.

The Divis site contributes significantly to thetelecommunicationsnetwork for much of Northern Ireland.

Services available

Digital television

Digital television services broadcast on the following frequencies with the following powers:

Frequency	UHF	kW	Operator	System
474.166MHz	21+	100	PSB2 (D3&4)	DVB-T
490.000MHz	23	50	COM4 (SDN)	DVB-T
498.000MHz	24	100	PSB3 (BBCB)	DVB-T2
514.000MHz	26	50	COM5 (ARQA)	DVB-T
522.000MHz	27	100	PSB1 (BBC A)	DVB-T
546.000MHz	30	50	COM6 (ARQ B)	DVB-T
594.000MHz	36	10	LTVmux	DVB-T
690.000MHz	48	0.01	NIMM (RTÉ)	DVB-T2
746.000MHz	55	8.9	COM7 (Closed)	DVB-T2

Before switchover

Frequency	UHF	kW	Operator
489.833MHz	23-	2.3	SDN(Mux A)
513.833MHz	26-	2.3	BBC(Mux B)
538.000MHz	29	2.3	BBC (Mux 1)
569.833MHz	33-	2.3	Digital 3&4(Mux 2)
578.166MHz	34+	1.6	Arqiva(Mux D)
690.000MHz	48	2	Arqiva (Mux C)

Analogue television

Analogue television services were broadcast on the following frequencies:

Frequency	UHF	kW	Service
471.25MHz	21	500	Channel 4
495.25MHz	24	500	UTV
519.25MHz	27	500	BBC Two Northern Ireland
551.25MHz	31	500	BBC One Northern Ireland
775.25MHz	59	—	TG4

All of the above channels, except TG4, were broadcast at a power of 500 kW. As well as providing direct reception for most TV viewers in Northern Ireland, all the other analogue transmitters in the province sourced their output, either directly or indirectly, from Divis. TG4, a channel operated by a state-owned body of theRepublic of Ireland,was broadcast at a very low power and not relayed to any other transmitters.Channel 5was broadcast from the nearbyBlack Mountain transmitting station.

Analogue radio

FMradio service broadcast on the following frequencies and with the following powers:

Frequency	kW	Service
90.1 MHz	250	BBC Radio 2
92.3 MHz	250	BBC Radio 3
94.5 MHz	250	BBC Radio Ulster
96.0 MHz	125	BBC Radio 4
99.7 MHz	250	BBC Radio 1
101.9 MHz	250	Classic FM

Digital radio

DABradio broadcasts on the following frequency:

Frequency	Block	kW	Operator
225.648 MHz	12B	10	BBC National DAB

External links

• Divis Transmitting Station at mb21.co.uk
• Divis Transmitting Station at thebigtowerArchived12 October 2012 at theWayback Machine