British Telecom TowerEdit profile
The BT Tower (formerly known as the Post Office Tower and, before that the GPO Tower) is a landmark in Birmingham, England, and is also the tallest building in the city. Its Post Office code was YBMR.History
Construction of the tower commenced in July 1963 and was completed in September 1965. The tower became operational in December 1966 and was officially opened by the Lord Mayor of Birmingham, Alderman James S. Meadows on 5 October 1967. It was designed by the Ministry of Public Building and Works with M.H. Bristow being the senior architect. It has 26 storeys, housing technical areas and offices, and five levels of circular aerial galleries at the top.
The original intention was to build a circular tower similar to the London one but without the public floors above the aerial galleries. At one time the Post Office wanted to increase the height from 500 feet, which had been agreed by the Ministry of Aviation, to 600 feet. This was refused in order to avoid non-standard procedures for aircraft approaching Birmingham Airport from the north-west. Cost over-runs on the London tower led to a review of the Birmingham design, and then it was decided to use a circular design of the 'Chilterns' type as used at Stokenchurch, Charwelton, Pye Green, Sutton Common, Heaton Park and Tinshill radio stations, but with the internal diameter increased from 32 feet to 37 feet to provide sufficient space on the equipment floors. The square design, as built, was proposed for aesthetic reasons by the Chief Architect of the Ministry of Public Building and Works.
The tower was designed to be stable in high winds. Channels at each corner funnel the wind to counteract the force of the wind swaying the building. A stable platform is necessary so that the microwave dishes mounted on the side of the building keep line of sight with the remote transmitter they are communicating with.
There were two steel rails on one wall on which a trolley was designed to run to carry the dishes up to the aerial galleries. The original horn dishes were too heavy for the roof mounted crane to lift and had to be stripped down, even in this state they were only just under the crane's maximum load capacity.
The ability to lift dishes was dependent on the weather and to complicate matters, the steel rails only went to the bottom of the first aerial gallery. To get the dishes higher a steel cable system was used that was mounted on poles. When the trolley reached the aerial gallery it had to be disconnected from the rails and swung out to attach to the cables.
In August 2003, the tower was painted an ultramarine blue to cover the existing light brown which had started to discolour. The balconies were painted to stand out from the tower in a dark shade of blue. On 18 March 2004, Jasper Carrott switched on the night time illuminations of the tower in response to Birmingham City Council's policy of encouraging the illumination of local landmarks.
The tower is home to a pair of Peregrines, with a webcam installed in 2010.Brindley House
The Birmingham and Fazeley Canal runs beneath the adjacent, decommissioned, Brindley House Telephone Exchange. This may have been the only telephone exchange in the world under which boats passed. Construction of Brindley House commenced in 1967 and was completed the following year. It was designed by D.K. McGowan. Brindley House is currently undergoing a refurbishment into apartments by MCD Developments. It will also be reclad and an extra floor is being constructed at the top.
As originally built there were 15 office floors at the front of the building and 10 equipment floors at the rear. It housed the equipment and test facilities for the 60 MHz coaxial cable systems, operator services using the new cordless switchboard system (CCS No 1) that replaced the operator positions that were found on the 4th floor of Telephone House and the associated switching equipment.
The 60 MHz system pushed the limits of coax cable and had 5 times the capacity of the 12 MHz system. The circuit breakdown is as follows - 12 channels in a group, 5 groups in a supergroup, 15 supergroups in a hypergroup (4 MHz), 3 hypergroups in a mastergroup (12 MHz) and 5 mastergroups in a supermastergroup (60 MHz). There were 12 calls in group, 60 calls in a supergroup, 900 calls in hypergroup, 2700 calls in a mastergroup and 13500 calls in a supermastergroup. Great care was taken in the route of the cables which were buried twice as deep as normal cables. These cables had 10 coaxs, or tubes, which meant there were 4 operational circuits and 1 spare.