Llanidloes transmitting station

The Llanidloes transmitting station is a broadcasting and telecommunications facility consisting of a self-supporting 23 m lattice mast erected on land that is itself about 245 m above sea level about 1 km to the west of the town of Llanidloes in Powys, Wales. It was originally built by the BBC,[1] entering service just before Christmas 1966 transmitting the now-defunct 405-line VHF television system. Transmissions of the original three FM radio services began in February 1967.

Llanidloes
Llanidloes transmitting station (Powys)
Mast height23 metres (75 ft)
Coordinates52.447858°N 3.548588°W / 52.447858; -3.548588
Grid referenceSN947843
Built1966
Relay ofLong Mountain
BBC regionBBC Wales
ITV regionITV Wales

Currently, the transmitter provides DVB-T digital television to the area, along with FM radio. With only 2 W ERP, the television broadcasts only cover the town of Llanidloes to the east, the radio broadcasts reach somewhat further east along the Severn valley towards Llandinam.

Specifications and history

As built, the 405-line television and VHF FM radio services came (indirectly) from Wenvoe near Cardiff, and this site was therefore classed as a relay of Wenvoe.

UHF television was added to the site in the late 1970s, launching with just the three programme services that were active at the time. S4C was added in 1982 when it launched. This made Llanidloes a very indirect off-air relay of Blaenplwyf, receiving its signal from Llandinam which relayed Long Mountain. Curiously, Long Mountain was classed as a relay of Blaenplwyf despite being fed from an SHF link from Blaenplwyf via Llangurig Link. A site was normally considered a "relay" only if it picked up its signal off-air.

Across the UK, 405-line television was finally shut down in January 1985.[2] However, Llanidloes was closed early - in the second quarter of 1983.[3]

When digital television was introduced in 2009, the site formally became a relay of Long Mountain which had now become classed as a main transmitter in its own right.

Services listed by frequency

Analogue television

19 December 1966 - Late 1975

BBC 405-line television started up with the site acting as an off-air relay transmitter of Llandrindod Wells about 25 km to the south.

Frequency VHF kW Service
214.75 MHz 13H 0.014 BBC1 Wales

Late 1975 - 1 November 1982

When 625-line colour television was added, the site additionally became an indirect relay of Blaenplwyf about 50 km to the west. The direct line-of-sight to Blaenplwyf is heavily obstructed and so Llanidloes rebroadcast the off-air signal from Llandinam's relay transmitter about 10 km to the east.

Frequency VHF UHF kW Service
214.75 MHz 13H — 0.014 BBC1 Wales
479.25 MHz — 22 0.005 BBC1 Wales
503.25 MHz — 25 0.005 HTV Wales
527.25 MHz — 28 0.005 BBC2 Wales

1 November 1982 - Second Quarter 1983

Channel 4 was added to the set transmitted from the site when it launched in November 1982. Being in Wales, Llanidloes radiated the S4C variant.

Frequency VHF UHF kW Service
214.75 MHz 13H — 0.014 BBC1 Wales
479.25 MHz — 22 0.005 BBC1 Wales
503.25 MHz — 25 0.005 HTV Wales
527.25 MHz — 28 0.005 BBC2 Wales
559.25 MHz — 32 0.005 S4C

Second Quarter 1983 - 4 November 2009

Llanidloes's Band III transmitter ended its service after 16 years. From then until the start of the digital switchover 26 years later, only UHF television would be available from the site.

Frequency UHF kW Service
479.25 MHz 22 0.005 BBC1 Wales
503.25 MHz 25 0.005 HTV Wales
527.25 MHz 28 0.005 BBC2 Wales
559.25 MHz 32 0.005 S4C

Analogue and digital television

4 November 2009 - 3 December 2009

Llanidloes's immediate off-air parent was always Llandinam which was an off-air relay of Long Mountain.[4] As part of the digital switchover plan, Long Mountain became a main transmitter in its own right. When the UK's digital switchover commenced at Llanidloes it therefore mirrored the changes taking place at Long Mountain. Analogue BBC Two Wales closed on channel 28 and ITV1 Wales took over on that frequency for what would be its final 3 weeks of service, vacating channel 25 as it did so. The new digital BBC A multiplex started up at full power in 64-QAM mode on channel 25.

Frequency UHF kW Service System
479.25 MHz 22 0.005 BBC One Wales PAL System I
506.000 MHz 25 0.002 BBC A DVB-T
527.25 MHz 28 0.005 ITV1 Wales PAL System I
559.25 MHz 32 0.005 S4C PAL System I

Digital television

3 December 2009 - present

All the analogue television services closed and the new digital multiplexes took over their frequencies.

Frequency UHF kW Operator
482.000 MHz 22 0.002 BBC B
506.000 MHz 25 0.002 BBC A
530.000 MHz 28 0.002 Digital 3&4

Analogue radio (FM VHF)

6 February 1967 - Circa 1990

From the outset, Llanidloes radiated the BBC's three FM radio services, acting as an off-air relay of Llandrindod Wells.[1]

Frequency kW Service
88.1 MHz 0.005 BBC Light Programme
90.3 MHz 0.005 BBC Third Programme
92.5 MHz 0.005 BBC Welsh Home Service

Present

Radio 2, Radio 3 and Radio Cymru still use the original frequencies that have been used since 1967, but Radio 1 launched in 1989 and at some point national Radio 4 was added which, along with Radio Cymru, have replaced the Welsh Home Service (later known as Radio Wales). The transmitters have also been upgraded to deliver 20 W each.

Frequency kW Service
88.1 MHz 0.02 BBC Radio 2
90.3 MHz 0.02 BBC Radio 3
92.5 MHz 0.02 BBC Radio Cymru
97.7 MHz 0.02 BBC Radio 1
104.8 MHz 0.02 BBC Radio 4
gollark: The moon snipers are obviously real, but not on the "moon".
gollark: There's no ice wall. It just loops over at the edges.
gollark: Why is it sometimes dark?
gollark: Why can't I go there and look at it if it's so real and extant?
gollark: How can something both be falling down due to gravity and staying up there every night?

See also

References
  1. http://downloads.bbc.co.uk/rd/pubs/reports/1968-16.pdf
  2. "Archived copy". Archived from the original on 13 August 2012. Retrieved 15 November 2013.CS1 maint: archived copy as title (link)
  3. "Archived copy" (PDF). Archived from the original (PDF) on 5 December 2014. Retrieved 4 April 2012.CS1 maint: archived copy as title (link)
  4. http://www.digitaluk.co.uk/transmitternetwork/tools__and__resources/almanac/installer_newsletters_transmitter_groups2009_pdfs/Installer_Newsletter_Long_Mountain_1_month_out_Updated_28_Oct_09.pdf
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