The Abergavenny transmitting station was originally built by the IBA in 1969 as a relay for BBC and ITV VHF405-line analogue television. It consists of a 46 m guyed lattice mast carrying the aerials at the top. This structure was built on a 440 m hill known as Gilwern Hill overlooking the towns of Gilwern and Abergavenny in Monmouthshire, South Wales. The band III VHF television feeds were provided off-air from St. Hilary and Wenvoe, both near Cardiff.
In 1973 the site was enhanced to transmit UHFanaloguecolour television. The UHF television feed came via a two-hop route from Wenvoe, via the Ebbw Vale repeater.
The 405-line VHF television service closed across the UK in 1985, but according to the BBC's and IBA's transmitter list and the BBC's internal "Eng. Inf." magazine, Abergavenny was due to close early - in the third quarter of 1982.
Currently, the hill's transmitters provide UHF digital terrestrial TV, VHF FM radio and DAB digital radio. The transmission station is currently owned and operated by Arqiva.
Freeview digital terrestrial TV was not available from this transmitter before the digital switchover process began at Wenvoe, with the first stage taking place on 31 March 2010. The second stage was completed on 27 April 2010.
Abergavenny transmitter initially provided BBC and ITV 405-line VHF television to the mid Usk valley area which is strongly shielded by local hills from both the Wenvoe transmitter and the St. Hilary transmitter.
The 405-line VHF TV services were shut down after 15 years. From then onwards TV transmissions were on UHF only. Channel 4 launched across the UK on 1 November 1982. Abergavenny (being in Wales) transmitted the S4C variant.
The UK's digital switchover commenced at Abergavenny on 31 March 2010. Analogue BBC Two Wales on channel 45 was first to close, and ITV Wales was moved from channel 49 to channel 45 for its last month of service. The new BBC A mux started up in 64-QAM and at full power (i.e. 200 W) on channel 49 which had just been vacated.
As a side-effect of frequency-changes elsewhere in the region to do with clearance of the 800 MHz band for 4G mobile phone use, Abergavenny's "BBC A" multiplex will have to be moved from channel 49 to channel 39.