History
The wider area around the Holyhead site includes older Post Office installations such as an early VHF link to Douglas (Isle of Man) and landing stations for cables. Some of the associated buildings remain and the SHF site is just north east of an ealier installation labelled "WT Station" (PO Telephones)".
In the mid-1970s an additional route between the UK and the Republic of Ireland was planned, connecting to the main SHF network at Manchester and running via North Wales to Holyhead. In the Republic the link appears to have been routed from Dublin via Three Rock Mountain.
The SHF installation features a short tower, not of one of the standard pattern. There were also several small towers to support further dishes facing out to sea, located on the sloping ground to the north west. The building appears to be of the standard design but is finished in stone - the overall design of the site seems to have been intended to minimise the visual impact and it is screened by higher ground in some directions.
An aerial view in 2006 shows the tower with at least two dishes facing east and one towards the west with one or two of the low-level mounts still in use. Originally the links would have been analogue and in the 4 GHz or 6 GHz bands. Early plans for the 1980s digital network appear to have excluded the route via Holyhead however the UK trunk network had converted to digital operation by 1990.
Following a long haitus during which SHF links seemed to dominate, a new cable was laid between Holyhead and Portmarnock (north east of Dublin) in 1988, capable of 6 x 140 MBit/s. Further cables followed in the 1990s, allowing GBit/s rates. With multiple cable routes in operation by the early 2000s there would appear to have been little benefit in retaining the SHF link even as a backup.
