Start Point transmitting station
Encyclopedia
The Start Point transmitting station is a broadcasting
facility at Start Point, Devon
, owned by National Grid Wireless. The site is just north-west of the Start Point lighthouse
.
The station currently transmits a single broadcast: BBC Radio 5 Live
on 693 kHz.
in Somerset. Start Point came on air on June 14th, 1939 using an ST&C
type C100 100 kW transmitter on 1050 kHz, and broadcast the West of England regional programme. A directional aerial array was used to avoid wasting power over the English Channel
and to enhance the signal to the east and west. It consisted of two 137.2 m ( 450 ft) stayed lattice masts, one being a mast radiator
and the other a parasitic reflector. Both masts had a break at 94.5 m ( 310 ft) to allow for the insertion of a loading coil
.
The station obtained power from two 11 kV mains feeders and a 400 kW diesel alternator.
The building design followed L. Rome Guthrie's earlier work at the Brookmans Park transmitting station. By agreement, the BBC obtained copyright in the Brookmans Park elevation drawings and was able to follow them, with changes to allow for building size, for several other sites.
The station closed on September 1st, 1939, in anticipation of the outbreak of war between Britain and Germany two days later.
A Marconi SWB18 short wave transmitter (Sender 22) was added to the station to carry the Home Service on 6075 kHz, from January 20th 1940. This was intended to provide coverage where the mediumwave
signals were poor, and to provide an emergency backup to the landline distribution network in case of major disruption. This transmitter also carried the European Service (Norwegian) at certain times.
In October 1940, the station began to transmit the European Service on 1050 kHz. This also used a horizontally-polarised antenna. The transmitter's power was increased to 180 kW, with a consequent increase in audio distortion.
Broadcasting
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
facility at Start Point, Devon
Start Point, Devon
Start Point is a promontory in the South Hams district. It is one of the most southerly points in Devon, England, . It marks the southern limit of Start Bay, which extends northwards to the estuary of the River Dart....
, owned by National Grid Wireless. The site is just north-west of the Start Point lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....
.
The station currently transmits a single broadcast: BBC Radio 5 Live
BBC Radio 5 Live
BBC Radio 5 Live is the BBC's national radio service that specialises in live BBC News, phone-ins, and sports commentaries...
on 693 kHz.
1930s
In 1935 the BBC started looking for transmitter sites to improve radio coverage in Devon, Dorset and Cornwall. After investigating 23 sites and carrying out extensive tests, two sites were selected: Start Point and ClevedonClevedon
Clevedon is a town and civil parish in the unitary authority of North Somerset, which covers part of the ceremonial county of Somerset, England...
in Somerset. Start Point came on air on June 14th, 1939 using an ST&C
Standard Telephones and Cables
Standard Telephones and Cables Ltd was a British telephone, telegraph, radio, telecommunications and related equipment R&D manufacturer. During its history STC invented and developed several groundbreaking new technologies including PCM and optical fibres.The company began life in London as...
type C100 100 kW transmitter on 1050 kHz, and broadcast the West of England regional programme. A directional aerial array was used to avoid wasting power over the English Channel
English Channel
The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...
and to enhance the signal to the east and west. It consisted of two 137.2 m ( 450 ft) stayed lattice masts, one being a mast radiator
Mast radiator
A mast radiator is a radio mast or tower in which the whole structure itself functions as an antenna. This design is commonly used for transmitting antennas operating at low frequencies, in the VLF, LF and MF ranges, in particular those used for AM broadcasting. The metal mast is electrically...
and the other a parasitic reflector. Both masts had a break at 94.5 m ( 310 ft) to allow for the insertion of a loading coil
Loading coil
In electronics, a loading coil or load coil is a coil that does not provide coupling to any other circuit, but is inserted in a circuit to increase its inductance. The need was discovered by Oliver Heaviside in studying the disappointing slow speed of the Transatlantic telegraph cable...
.
The station obtained power from two 11 kV mains feeders and a 400 kW diesel alternator.
The building design followed L. Rome Guthrie's earlier work at the Brookmans Park transmitting station. By agreement, the BBC obtained copyright in the Brookmans Park elevation drawings and was able to follow them, with changes to allow for building size, for several other sites.
The station closed on September 1st, 1939, in anticipation of the outbreak of war between Britain and Germany two days later.
World War II
In October 1939 BBC Research engineers experimented with horizontally-polarised transmissions at Start Point. The idea was to see if broadcasts could be made without providing enemy aircraft with a navigational radio beacon. A horizontal dipole antenna was suspended between the two masts. The test was reasonably successful and between February 18th and September 15th, 1940 regular transmission were carried in the evenings, on 877 kHz, of what became the "Forces' Programme".A Marconi SWB18 short wave transmitter (Sender 22) was added to the station to carry the Home Service on 6075 kHz, from January 20th 1940. This was intended to provide coverage where the mediumwave
Mediumwave
Medium wave is the part of the medium frequency radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz...
signals were poor, and to provide an emergency backup to the landline distribution network in case of major disruption. This transmitter also carried the European Service (Norwegian) at certain times.
In October 1940, the station began to transmit the European Service on 1050 kHz. This also used a horizontally-polarised antenna. The transmitter's power was increased to 180 kW, with a consequent increase in audio distortion.