Coast Defence/Chain Home Low Station M73
Coast Defence/Chain Home Low Station M73 is a former radar station in the northern region of Tout Quarry, close to Priory Corner and overlooking Lyme Bay. The station, named M73 (Westcliff), was constructed by the British Army during World War II as an early warning radar system, allowing shipping and aircraft movement to be monitored and targeted.
History
Coast Defence/Chain Home Low (CD/CHL) stations were borne out of the need to detect and assist in the direction of fire at enemy surface shipping, at a time when there was an anticipated German invasion of Britain. The War Office developed their plans for a network of CD/CHL stations in 1940. These stations were independent of the RAF's own network of Chain Home Low stations, which provided early warning system against hostile aircraft, and allowed RAF fighters to intercept the enemy more quickly and efficiently. The British Army's Coast Defence radar was developed in 1938 for detecting and directing fire at enemy surface shipping. When it was found to be effective in detecting aircraft flying as low as 500 feet, something the original Chain Home could not accomplish, CD was also adopted by the RAF and renamed Chain Home Low (officially known as AMES Type 2) to replace their original Chain Home network.
The earliest of the Army's CD/CHL stations became operational in early 1941. Two sites were established at Portland during that year: M73 (Westcliff) was sited on the west side of Portland and M72 (Eastcliff) on the east side. Many of the CD/CHL stations followed a standard design, consisting of a combined transmitter, receiver and operations block with an aerial gantry mounted on the roof, and a separate standby set house for reserve power. M73's transmitter, receiver and operations block was built on a summit overlooking Lyme Bay and its standby set house was built in a gulley below. Other buildings were established below the summit's north side and on its lower space to the south, which are likely to have included accommodation and other facilities for the station's personnel.
M73 was used to detect shipping and aircraft, and produce the range and bearings of a target. This information would be passed to Portland's fire command post and/or the naval plotting room, both of which had direct lines of telephone communication with M73. It was from the F.C. post that information and orders to engage an enemy vessel could be given to the area's batteries. Reports on aircraft would be passed from the F.C. post to the gun operations room at Nottington House in Weymouth, from where local anti-aircraft defence was coordinated.
In 1942, a number of CD/CHL stations were transferred to the RAF under the "Triple-Service" agreement, which saw radar coverage for shipping and aircraft unified. While the Army retained their M72 (East Cliff) station, the transfer of M73 took place in April 1942. After its transfer, the station was considered to be the least useful on Portland to the Army, being described in F.C. Portland's fighting book as "under R.A.F. and of little use to F.C." and "not usually very helpful".
After World War II, M73 remained operational into the Cold War. During the early 1950s, it was used as part of the ROTOR project, possibly as a R/T (TX and RX) site. This air defence radar system was built by the British Government to counter possible attack by Soviet bombers. The system primarily used World War II-era radar systems and was only briefly operational before being replaced by the more modern Linesman/Mediator system. During the 1950s, two large radar towers were erected at West Cliff; one on the next summit east of the M73 site and another further south towards the disused Trade Quarries.
After the ROTOR period, the Royal Navy took control of the station for assistance in air to ground communications, where it was used in connection with RN Air Station Portland (HMS Osprey), which itself was established in 1959. Once no longer required, the station was demolished during the 1960s, along with the radar tower on the adjacent summit, and a 1910 position finding cell associated with Blacknor Battery. The other tower further south was retained by the Ministry of Defence until 1977.
Various remains of the station can still be seen today including brick rubble (thrown into a gulley), mast bases, power cables and a duct cable entry. There are also remains of the southern radar tower's base, along with rubble from its ancillary building.
References
The following is an A-Z list of references for this page.
1) Aerial.Freeserve - G8HUL's Web Page - Radar Sites on Portland - website page
2) Building Radar: Forging Britain's Early-warning Chain, 1939-45 - Colin Dobinson - Methuen Publishing Ltd - 2010 - book
3) Exploring Portland - Tout Quarry Sculpture Park And West Weares: World War 2 Radio Station - Geoff Kirby - website page
4) Frontline Dorset - A County at War 1939-45 - George Forty - Dorset Books - 1994 - ISBN: 978-1871164213 - page 45 - book
5) Pastscape - Chain Home Extra Low Station K73 - website page
6) Pastscape - Coastal Defence/Chain Home Low Station M72 - website page
7) Pastscape - Coastal Defence/Chain Home Low Station M73 - website page
8) Thanks also to Stuart Morris for providing the south tower's year of demolition
9) The National Archives - Fire Command, Portland - WO 192/150 - fort record book - 1941-44 - website page
10) Wikipedia - Chain Home - website page
11) Wikipedia - Chain Home Low - website page
History
Coast Defence/Chain Home Low (CD/CHL) stations were borne out of the need to detect and assist in the direction of fire at enemy surface shipping, at a time when there was an anticipated German invasion of Britain. The War Office developed their plans for a network of CD/CHL stations in 1940. These stations were independent of the RAF's own network of Chain Home Low stations, which provided early warning system against hostile aircraft, and allowed RAF fighters to intercept the enemy more quickly and efficiently. The British Army's Coast Defence radar was developed in 1938 for detecting and directing fire at enemy surface shipping. When it was found to be effective in detecting aircraft flying as low as 500 feet, something the original Chain Home could not accomplish, CD was also adopted by the RAF and renamed Chain Home Low (officially known as AMES Type 2) to replace their original Chain Home network.
The earliest of the Army's CD/CHL stations became operational in early 1941. Two sites were established at Portland during that year: M73 (Westcliff) was sited on the west side of Portland and M72 (Eastcliff) on the east side. Many of the CD/CHL stations followed a standard design, consisting of a combined transmitter, receiver and operations block with an aerial gantry mounted on the roof, and a separate standby set house for reserve power. M73's transmitter, receiver and operations block was built on a summit overlooking Lyme Bay and its standby set house was built in a gulley below. Other buildings were established below the summit's north side and on its lower space to the south, which are likely to have included accommodation and other facilities for the station's personnel.
M73 was used to detect shipping and aircraft, and produce the range and bearings of a target. This information would be passed to Portland's fire command post and/or the naval plotting room, both of which had direct lines of telephone communication with M73. It was from the F.C. post that information and orders to engage an enemy vessel could be given to the area's batteries. Reports on aircraft would be passed from the F.C. post to the gun operations room at Nottington House in Weymouth, from where local anti-aircraft defence was coordinated.
In 1942, a number of CD/CHL stations were transferred to the RAF under the "Triple-Service" agreement, which saw radar coverage for shipping and aircraft unified. While the Army retained their M72 (East Cliff) station, the transfer of M73 took place in April 1942. After its transfer, the station was considered to be the least useful on Portland to the Army, being described in F.C. Portland's fighting book as "under R.A.F. and of little use to F.C." and "not usually very helpful".
After World War II, M73 remained operational into the Cold War. During the early 1950s, it was used as part of the ROTOR project, possibly as a R/T (TX and RX) site. This air defence radar system was built by the British Government to counter possible attack by Soviet bombers. The system primarily used World War II-era radar systems and was only briefly operational before being replaced by the more modern Linesman/Mediator system. During the 1950s, two large radar towers were erected at West Cliff; one on the next summit east of the M73 site and another further south towards the disused Trade Quarries.
After the ROTOR period, the Royal Navy took control of the station for assistance in air to ground communications, where it was used in connection with RN Air Station Portland (HMS Osprey), which itself was established in 1959. Once no longer required, the station was demolished during the 1960s, along with the radar tower on the adjacent summit, and a 1910 position finding cell associated with Blacknor Battery. The other tower further south was retained by the Ministry of Defence until 1977.
Various remains of the station can still be seen today including brick rubble (thrown into a gulley), mast bases, power cables and a duct cable entry. There are also remains of the southern radar tower's base, along with rubble from its ancillary building.
References
The following is an A-Z list of references for this page.
1) Aerial.Freeserve - G8HUL's Web Page - Radar Sites on Portland - website page
2) Building Radar: Forging Britain's Early-warning Chain, 1939-45 - Colin Dobinson - Methuen Publishing Ltd - 2010 - book
3) Exploring Portland - Tout Quarry Sculpture Park And West Weares: World War 2 Radio Station - Geoff Kirby - website page
4) Frontline Dorset - A County at War 1939-45 - George Forty - Dorset Books - 1994 - ISBN: 978-1871164213 - page 45 - book
5) Pastscape - Chain Home Extra Low Station K73 - website page
6) Pastscape - Coastal Defence/Chain Home Low Station M72 - website page
7) Pastscape - Coastal Defence/Chain Home Low Station M73 - website page
8) Thanks also to Stuart Morris for providing the south tower's year of demolition
9) The National Archives - Fire Command, Portland - WO 192/150 - fort record book - 1941-44 - website page
10) Wikipedia - Chain Home - website page
11) Wikipedia - Chain Home Low - website page
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