Site Records


Site Name: RAF Schoolhill - Chain Home Radar Station

Schoolhill
Portlethen
Aberdeenshire
OS Grid Ref: NO908982

Sub Brit site visit 29th June 2004

[Source: Nick Catford]

Following the development of radar at Orfordness and at the Bawdsey Research Station in Suffolk during the mid 1930's, the Air Ministry established a programme of building radar stations around the British coast to provide warning of air attack on Great Britain. A survey was undertaken in 1938 to assess the suitability of the local terrain for Air Defence Radar operations with the first of these new stations coming on line by the end of the year. This network formed the basis of a chain of radar stations called CHAIN HOME (CH).

These stations consisted of two main types; East Coast stations and West Coast stations. The East Coast stations were similar in design to the experimental station set up at Bawdsey in 1936. In their final form these stations were designed to have equipment housed in protected buildings with transmitter aerials suspended from 350' steel towers and receiver aerials mounted on 240' timber towers.

The West Coast stations differed in layout and relied on dispersal instead of protected buildings for defence. Thus the West Coast stations had two transmitter and receiver blocks with duplicate equipment in each. Transmitter aerials were mounted on 325' guyed steel masts with the receiver aerial mounted on 240' timber towers.

The majority of Chain Home stations were also provided with reserve equipment, either buried or remote. Buried reserves consisted of underground transmitter and receiver blocks, each with three entrance hatches (two for plant and one for personnel) set on steel rollers. Nearby were the emergency exit hatch, ventilation shafts and 120' wooden tower carrying the aerials. On some stations the transmitter and receiver buried reserves were together on an adjoining site (often the next field).At others the two buried reserves were separate but located close to their respective above ground building. Many of the West Coast stations had remote reserves some distance from the main station but utilising similar above ground transmitter and receiver blocks.

Photo:The transmitter block
Photo by Nick Catford

Most stations were powered from the National Grid but they were also provided with generators to cover interruptions in the mains electricity supply. These were located in another protected building known as a stand-by set house. These were similar in design to the transmitter and receiver block although smaller and were of brick construction and surrounded by a traverse (earth banks) for blast protection.

The East Coast Chain Home station at Schoolhill was opened in about 1940 and remained operational through the war. There is little recorded operational history about the station but in mid 1942 two of the 350' steel towers were taken down to be supplied to a Gee radio station and they were replaced by 325' guyed masts which would normally only be supplied to west coast Chain Home stations.

At the end of the war RAF Schoolhill was placed on care and maintenance but was later selected as one of 15 stations promoted to a 'readiness chain home'. The station was equipped with a Type 1 radar and two channels, as part of the first phase of the rotor programme. (Code HSL). With introduction of Type 80 radar in 1955 RAF Schoohill was redundant.

Map showing the major buildings at RAF Schoolhill. The receiver site has now been completely cleared and three large warehouses built on the site.

In 1964 the transmitter block was acquired by the Home Office to provide a temporary location for the United Kingdom Warning and Monitoring Organisation's (UKWMO) Caledonian Sector Control. This had been co-located with the Caledonian ROTOR Sector Operations Centre (SOC) at Barnton Quarry but with the demise of the SOC's in the mid 1950's, the bunker at Barnton Quarry provided protected accommodation for a regional seat of government (RSG11) in the early 1960's and there was no longer room for the Caledonian Sector Control.

The UKWMO remained at Schoolhilll until 1976 when it was relocated to the ROC Group Headquarters at Craigiebarns in Dundee.

Grampian Fire Brigade took over the Schoolhill site in 1978, as a training centre for offshore fire fighting on north seas oil rigs. The fire brigade has expanded the site and it is hoped to find a continued training use for the old Chain Home transmitter block. As part of a new development on the site the stand-by set house was demolished in 2003. A number of aerial mast bases still stand within the transmitter compound together with two losenge shaped pillboxes on the field boundary. Both of these pillboxes have a triangular metal framework on each end of the roof. This could have been used to support camouflage netting but it has also been suggested that the pillboxes at Schoolhill were disguised as haystacks.

The domestic camp was south west of the transmitter block, alongside the modern Grampian Fire Brigade headquarters building which stands on the site of the combined living accommodation huts. The two warden married quarters still stand alongside a short drive; they are now in private ownership and somewhat altered. At the end of the drive the Seco guard house also stands. There are two other huts and a small brick building within the domestic area, it's impossible to determine their original purpose.

The receiver block was on the opposite side of the road but this has now been completely cleared and the site is now occupied by three large warehouses. The receiver site also included a watch house and a second pair of wardens cottages but these have gone without trace. A third lozenge shaped pillbox still stands however on the boundary fence line to the rear of the warehouses.


Photo: Buried reserve showing the three access hatches on steel rollers and the unusually tall ventilator behind.
Photo by Nick Catford

The two buried reserves are within 30 yards of each other on farmland 100 yards east of the transmitter block. The main access was by moving three flat reinforced concrete covers mounted on steel rollers and running rails. The two larger covers were for plant access and the smaller cover gives access to a steel staircase down 17' 5" into the bunker. Close to each set of hatches there are three cement rendered brick ventilators with wooden slats for intake and exhaust ventilation. Each reserve has two short ventilators standing about two feet high with the wooden slats missing and a long ventilator standing approximately 16 feet high. It is unclear why two of the ventilators at Schoolhill are so tall, at other buried reserves all the ventilators are the same height.

Close to each reserve there are four concrete bases for the 120' high reserve masts. A short section of steel for fixing the wooden legs still protrudes from each concrete base. Each reserve also has an emergency escape shaft with the steel hatches still in place.

The two buried reserve bunkers are completely flooded and are used by the police for diver training.

For further information and pictures of the Caledonian Sector Control in the old transmitter block click here
For further pictures of RAF Schoolhill click here


[Source: Nick Catford]

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