| Three Rock Mountain | |
|---|---|
 Masts on Three Rock Mountain | |
| Highest point | |
| Elevation | 448 m (1,470 ft)[1] |
| Coordinates | 53°14′43″N6°14′21″W / 53.24528°N 6.23917°W /53.24528; -6.23917[2] |
| Naming | |
| Native name | Binn Trí Charraig / Sliabh Ruadh |
| Geography | |
  Three Rock Location in Greater Dublin Show map of Dublin Three Rock Three Rock (island of Ireland) Show map of island of Ireland | |
| Location | Dún Laoghaire–Rathdown, Ireland |
| Parent range | Dublin Mountains |
| OSI/OSNI grid | O176231 |
| Topo map | OSI Discovery No. 50 |
Three Rock Mountain (Irish:Binn Trí Charraig;[3]archaic:Sliabh Ruadh[4]) is a mountain inCounty Dublin, Ireland. It is 444 metres (1,457 feet) high[1] and forms part of the group of hills in theDublin Mountains which comprisesTwo Rock, Three Rock,Kilmashogue andTibradden mountains.[5]
The mountain takes its name from the three groups ofgranite rocks at the summit.[6] It was once believed that these features were man-made: for instance,Gabriel Beranger wrote of them in 1780, "I take them to be altars upon which sacrifices were offered […] the regularity which is observed in piling them convinces me they are the work of man, as they could not grow in that position".[7] In fact, the three outcrops aretors: natural geological features produced by the gradual process ofweathering.[6]
Today, the summit is dominated by the manyradio masts and towers that use the site to broadcast their signals across the Dublin area below.[8] The forestry plantations on the slopes consist mainly ofSitka spruce,Japanese larch,Scots pine,Monterey pine andlodgepole pine.[1]
The views from the summit are extensive and have attracted visitors for many years.[9] The writer Weston St. John Joyce described the vista thus: "The view from this commanding height, 1,479 feet over sea-level, extends over a vast tract of mountain, sea, and plain, comprising, to the north, the blue waters ofDublin Bay, withClontarf andHowth, theNaul or Man-of-War hills, and theMourne Mountains; eastward,Kingstown,Dalkey, andKilliney, and then in succession the fertile vale of Shanganagh,Carrickgollogan,the Scalp,Bray Head, theSugar Loaves, and the slopes of Prince William's Seat. In clear weatherHolyhead and the Welsh mountains may frequently be discerned,Snowdon and theLlanberis Pass being usually the most conspicuous, but occasionally the elongated outline ofCader Idris may be observed some distance to the right".[10] By way of contrast, Gabriel Beranger said of Three Rock, "The extensive summit of this mountain, the parched ground and its solitude, make it the most awful spot I had ever seen".[7]
Access to the mountain is possible via theCoillte-owned forest recreation areas ofTicknock and Kilmashogue.[1] The route via Kilmashogue follows theWicklow Way hiking trail for part of the way.[11] Three Rock is also traversed by theDublin Mountains Way hiking trail that runs betweenShankill andTallaght.[2] In 2007 a concept was submitted toDún Laoghaire–Rathdown County Council to create a cableway from theSandyford Luas stop to Three Rock Mountain and to open up the views to touristic and easier access.[12]
Several local sports clubs take their name from the mountain such as theThree Rock Orienteering Club has mapped the area and runorienteering competitions there since 1981[13] as well asThree Rock Rovers Hockey Club[14] (field hockey) andThree Rock Rovers association football club.[citation needed]
On the top of the central tor at the summit are four bowl-shaped depressions: these arebullauns which were used in early Christian times for grinding.[15] At one time, to the east of central tor was the remains of an abandonedpublic house.[15]
Close to the summit is the ruins of an old armyshooting range which closed in the 1970s.[16] The targets were raised and lowered by 12 men using levers in a concrete dugout.[17] A red flag was raised along the forest road to alert visitors that firing exercises were in progress.[17]
The remains of severalhill forts,ring forts and otherenclosures are to be found on the slopes of the mountain though they have largely disappeared under the forestry plantations.[18][19]
During the nineteenth century, much of the lower slopes of Three Rock were covered with small quarries, especially around the village ofBarnacullia, which supplied paving stones forDublin Corporation for many years.[20] Close to Barnacullia was a cottage that was occupied for many years by theCountess Markievicz up until the 1916Easter Rising.[21] The children ofJames Connolly stayed at the cottage during the week of the Rising.[21] During theIrish War of Independence (1919–21) the 6th Battalion of the Dublin Brigade established a camp at Barnacullia.[22]
Further down the slopes, near the Ticknock Road, is aholy well, known as Grumley's Well, reputed to cure eye ailments.[23]
The main transmission site on Three Rock is owned and operated by2RN a subsidiary of the Irish national broadcasterRTÉ, its 140-metre (360') cable-stayed mast is close to the peak, which is 448 metres (1470') aboveOrdnance Datum.
This site, andCairn Hill in County Longford, were the firstUHF television transmitters built by RTÉ to facilitate the introduction of their second television channel (RTÉ 2) in 1978. Both transmitters also helped improve television reception in their respective service areas. Since 1961 Dublin city had been served by theKippure VHF television transmitter in County Wicklow which did not cover some Eastern and Southern parts of the city very satisfactorily. A low-power VHF TV relay transmitter (now defunct) had broadcast from the links tower at the RTÉ campus in Donnybrook to serve most of the districts not reached byKippure. The original transmission tower on the site was superseded by the present 140m mast in 2002, but the tower remains as amicrowave link facility carrying service feeds for broadcast and telecoms.
Today the Three Rock transmitters provide the Irishdigital television service,Saorview, toDublin city and county,[24] as well as FM andDAB radio networks. Other masts at the site carry the majority of Dublin's local radio stations.
| Frequency | UHF | kW | Multiplex | Pol |
|---|---|---|---|---|
| 546 MHz | 30 | 125 | Saorview 1 | H |
| 570 MHz | 33 | 125 | Saorview 2 | H |
| Frequency | kW | Service |
|---|---|---|
| 88.5 MHz | 5 | RTÉ Radio 1 |
| 90.7 MHz | 5 | RTÉ 2fm |
| 96.7 MHz | 5 | RTÉ lyric fm |
| 92.9 MHz | 5 | RTÉ Raidió na Gaeltachta |
| 94.9 MHz | 1.5 | Classic Hits 4FM[25] |
| 98.1 MHz | 5 | Dublin's 98FM |
| 100.3 MHz | 12.5 | Radio Nova 100 |
| 101.8 MHz | 0.5 | Today FM[26] |
| 102.2 MHz | 2 | Q102 |
| 103.2 MHz | 1 | Dublin City FM[27] |
| 103.8 MHz | 5 | SPIN 1038 |
| 104.4 MHz | 5 | FM104 |
| 106.0 MHz | 10 | Newstalk |
| 106.4 MHz | 0.5 | Raidió Na Life[28] |
| 106.8 MHz | 0.5 | Sunshine 106.8 |
| DTT Relay | County | Mux 1 | Mux 2 | kW | Pol |
|---|---|---|---|---|---|
| Greenore | Louth | 41 | 44 | 0.2 | V |
| Greystones | Wicklow | 42 | 45 | 0.5 | V |
