ROTOR

Entrance bungalow to former ROTOR station at Kelvedon Hatch

ROTOR was a huge and elaborate air defence radar system built by the British Government in the early 1950s to counter possible attack by Soviet bombers. The system was built up primarily of war-era radar systems, and was used only briefly before being replaced by the more modern Linesman/Mediator system. A similar expedient system in the United States was the Lashup Radar Network.

Post-war situation

UK radar operations were wound down late in the war, and by the time the war ended were already largely unused. It was assumed that another war was at least ten years away, and the need for any improvements in the cobbled-together system seemed remote.

Thinking changed dramatically in 1949 with the Soviet test of their first atom bomb. It was known that the Soviets had made exact copies of the B-29 Superfortress as the Tu-4 Bull, and these aircraft had the performance needed to reach the UK with a nuclear payload. Studying the problem, the 1949 Cherry Report suggested that the 170 existing Royal Air Force radar stations be reduced to 66 sites and the electronics extensively upgraded.

Most of the new network would be made up of 28 re-built Chain Home systems, while the rest were taken from the existing selection of Chain Home Low, Chain Home Extra Low and the various Ground-controlled interception (GCI) radars that had formerly served special purposes. This was, in part, a stop-gap measure anticipating the availability of the dramatically improved Type 80 Green Garlic radar which would replace the various early warning radars with a single system of much greater performance. Interception guidance would still be handled by existing systems in either case.

All of the radars were to be improved in terms of siting with the addition of hardened control bunkers to protect the operators from a conventional attack. On the east coast, the coast toward which a Soviet attack would be most likely, the bunkers were underground in the 'R' series (R1, R2, R3 and R4 etc.), while those on the western side of the UK were generally semi-sunken hardened structures ('R6') or above ground 'Secco' type huts (Hartland Point etc.). The R-series bunkers themselves were otherwise similar, featuring 10-foot-thick (3.0 m) concrete walls with all equipment, operations generators and air conditioning located inside.

Additionally, ROTOR re-arranged the existing RAF Fighter Command structure into six "Sector Operational Commands" (SOC) with their own command bunkers (three level 'R4' protected accommodation). Only four of these were built. Additional "Anti-Aircraft Operations Rooms" were built to coordinate the British Army's AA defences in the same overall system. The entire network of bunkers, radars, fighter control and command centres used up 350,000 tons of concrete, 20,000 tons of steel and thousands of miles of telephone and telex connections.

The work was mainly carried out by the Marconi Wireless and Telegraph Company in several phases, called ROTOR 1, ROTOR 2 and ROTOR 3.

Post-ROTOR

As the anticipated Type 80 "Green Garlic" radar started testing shortly after ROTOR came online, it became clear that it could fill both early warning and interception guidance from a single site. This dramatically decreased the complexity of the ROTOR system, which otherwise required sightings from the early warning radars to be telephoned to the fighter control GCI stations for local plotting. By concentrating all of this complexity at a single site the total number of operators was greatly reduced.

As a result of the introduction of the Type 80 (Green Garlic), many of the existing ROTOR sites were rationalized into Master Radar Stations (MRS), while the rest were made redundant, some only two years after opening, and all of the AAOR sites were closed. A few of these were re-used for government department ('RSG's) and local authority wartime headquarters. In the mid-1960s the MRSs themselves were replaced with a new system called Linesman/Mediator.

Until the end of the Cold War many of the sites were retained by the government but now have been sold off to private buyers or converted into museums (for example 'RAF Hack Green') and some transferred to the National Air Traffic Control Centre.

List of ROTOR sites

Site Name	Site Designator	Grid Reference	Site Purpose
Aird Uig	WIU	NB 047390	R10 CEW Type 80
Anstruther	FAT	NO 568808	R3 Type 80
Barnton Quarry	MHA	NT 203748	R4 SOC Caledonian Sector
Bawburgh	WRK	TG 165080	R4 SOC Eastern Sector
Bawdsey	PKD	TM 347388	R3 GCI(E)
Beachy Head	HEB	TV 590959	R1 CEW Type 80
Bempton	RMF	TA 192736	R1 CEW
Boulmer	EZS	NU 240125	R3 GCI Type 80
Box	XOB	ST 850690	SOC Southern Sector
Buchan	GBU	NK 113408	R3 GCI Type 80
Calvo	CAL	NY 144545	R8 GCI
Charmy Down	CHA	ST 768702	R8 GCI
Chenies	HAM	TQ 015997	R8 GCI
Cold Hesledon	IDW	NZ 417468	R1 CEW/CHEL
Comberton	COB	SO 968461	R8 GCI
Crosslaw	HCV	NT 880680	R2 CHEL
Danby Beacon		NZ 732097	CH
Douglas Wood		NO 488415	CH
Drone Hill		NT 845665	CH
Drytree		SW 732218	CH
Dunkirk	TDE	TR 076595	CH Type 80
Fairlight	GWB	TQ 862113	R2 CHEL(A)
Faraid Head	RAI	NC 389714	R10 CEW Type 80
Folly		SM 858195	CH
Foreness	WJW	TR 385710	R2 CHEL
Gailes	FUL	NS 327361	R8 GCI Type 80
Goldsborough	JEX	NZ 830138	R2 CHEL(A)
Hack Green	HAK	SJ 647483	R6 GCI
Hartland Point	HAT	SS 237277	R8 GCI
Hayscastle Cross	CHX	SM 920256	CH Type 80
High Street		TM 411720	CH
Hill Head		NJ 947616	CH
Holmpton	VQJ	TA 367225	R3 GCI(B) Type 80
Hope Cove	HOP	SX 716374	R6 GCI
Hopton	TOH	TM 540990	R2 CHEL(B)
Inverbervie	LGZ	NO 841734	R1 CEW
Kelvedon Hatch	XSL	TQ 561995	R4 SOC Metropolitan Sector
Kilchiaran	ECK	NR 207616	R11 CHEL
Killard Point		IJ 605435	R8 GCI Type 80
Langtoft	LAT	TF 155129	R6 GCI Type 80
Longley Lane	LOA	SD 541365	SOC Western Sector
Murlough Bay	URB	ID 213407	R11 CHEL
Neatishead	BWP	TG 346184	R3 GCI
Netherbutton	BNT	HY 464045	CH
Pevensey		TQ 644073	CH
Poling		TQ 043052	CH
Portland	NIB	SY 696735	R1 CEW
Prestatyn	SYP	SJ 079819	R11 CHEL
Ringstead		SY 751817	CH
Rye		TQ 968232	CH
Sandwich (Ash)	YTM	TR 303574	R3 GCI Type 80
Saxa Vord	AXA	HP 629165	R10 CEW Type 80
Scarinish	FLY	NM 032456	R8 GCI Type 80
School Hill	HSL	NO 908982	CH
Seaton Snook	DYR	NZ 519280	R3 GCI Type 80
Sennen		SW 376246	CH
Shipton	KFY	SE 542618	R4 SOC Northern Sector
Skendleby	UPI	TF 438709	R3 GCI
Snaefell	MOI	SC 397869	R11 CHEL
Sopley	AVO	SZ 163977	R3 GCI Type 80
St Annes	SAN	SD 348303	R8 GCI
St Margarets	AGC	TR 370451	R1 CEW
St Twynnells	TWY	SR 944976	R6 GCI Type 80
Staxton Wold		TA 023778	CH
Stenigot		TF 256827	CH
Stoke Holy Cross		TG 257028	CH
Swingate		TR 335429	CH
Trelanvean		SW 762193	CH
Treleaver	TEL	SW 766174	R6 GCI(B) Type 80
Trerew	RTW	SW 812585	CH
Trewan Sands	TES	SH 322754	R8 GCI
Trimingham	QLE	TG 290385	R1 CEW Type 80 CHEL
Truleigh Hill	SNG	TQ 224109	R2 CHEL
Ventnor	OJC	SZ 565784	CH R1 CEW Type 80
Wartling	ZUN	TQ 662088	R3 GCI Type 80
West Beckham		TG 142389	CH
West Myne	ZEM	SS 928486	R11 CHEL
West Prawle		SX 771374	CH
Wick	IKA	ND 326537	R8 GCI

ROTOR sites today

See here for modern aerial site photographs of both 'retained' Chain Home and ROTOR sites.

RAF Staxton Wold is the only Chain Home site still used as a military radar site but with no remains of the CH station on site after being rebuilt for Linesman/Mediator in 1964. Today it is the home of an RAF TPS 77 RRH (remote radar head).^[1]

In terms of current condition, the ROTOR sites vary from demolished to intact.

For example, West Myne^[2] in Somerset was the last ROTOR 3 CHEL site. It was completed in 1957 after the introduction of the type-80 radar and after many ROTOR stations had already closed. The site was within Exmoor National Park and its creation was strenuously opposed by the National Trust who lost no time in obliterating the site immediately after closure.

Many of the buildings have been re-purposed since being active as ROTOR sites. An example is the Bawburgh R4 SOC^[3] which was re-purposed as SRHQ4.1 and then RGHQ4.1 to suit the evolving needs of government. The building is intact, but it has been significantly reconfigured since its use as a ROTOR SOC, notably with the addition of an extra floor and the flooring-over of the original R4 operations well.

References

External links

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