Wednesday, 30 January 2013

The First Radar on Unst

Following the invasion of Poland, Britain declared war on Germany on 3 Sep 1939.  After the quick German success in Poland a period of about 6 months ensued, now sometimes known as the “phoney war”, when it might have appeared that Germany could be resting on its laurels and concentrating on absorbing its new territories. Then on 9 Apr 1940, probably surprising most of the British establishment, German forces invaded both Denmark and Norway.
During WW1 most British forces were involved in fighting in France and Belgium with the main threat to the UK being to the Home Counties. The sudden invasion of Denmark & Norway in Apr 40 shifted the threat axis. A look at the map below will help understand the planner’s reactions. (Left click or zoom on pictures to enlarge):
Successful German campaigns would bring airfields from which they could operate against Scapa Flow – base of the UK Home Fleet. It would also bring RAF Sullom Voe within range – since Aug 39 Saro London and Sunderland Flying boats had been based there – essential in helping to prevent German surface ships & u-boats getting easy access to the North Atlantic. The capture of an island or two in the Hebrides, Orkneys or Shetlands could establish a base to launch an attack against a sparsely populated and less well defended part of UK.
Norway had been sympathetic to the allied cause and both France & Britain had treaties with Norway. For once the British reaction was almost instantaneous. The Royal Navy had a significant number of ships in the area, including the aircraft carrier HMS Glorious. These vessels became active in supporting the Norwegians almost immediately. An expeditionary force with both British & French troops was dispatched within days – the first British troops landing in Norway on 12 Apr 40 with the main force arriving in the Trondheim area 5 days later. By the 24 Apr No 263 Sqn RAF (Gladiators) had set up a base on a frozen lake. The short campaign in Norway can be read about elsewhere. The few things I’ve mentioned are to illustrate the major reallocation of resources sometimes required when the enemy does the unexpected.

So, what’s all this got to do with Unst? Two radar stations were already planned for Unst and work was going on.  The RN Admiralty Experimental Station Number 4 on Saxa Vord was in the pipeline, but it was not the Navy’s highest priority and would not be ready until Sep ‘40.
The RAF was building RAF Skaw, a Chain Home radar at Lamba Ness, but that too was nowhere near completion – the first operations crew not arriving on site until Nov ‘40. It was decided that radar cover to the north and east of Scapa & Sullom was essential and that it must be provided quickly. It was also a possibility that the planners wanted a radar in the area to help cover the expeditionary force resupply and routine surveillance of aircraft movements associated with it.

Operational radar was still in its infancy but its potential had been recognised by all 3 services. Equipment was in short supply and technological developments were rapid. However, the need for “transportable” radar had been recognised and the RAF had orders placed for 2 sets of equipment.  This new situation was deemed important enough for the provision of an extra transportable radar and so, on 11 Apr 40, the decision to form Number 3 Transportable Radio Unit (3 TRU) was taken.
The equipment was gathered, probably some of it originally destined for use as Army gun-laying radar, and the personnel (mainly inexperienced), allocated.  In the wartime conditions in the first half of 1940 it is almost unbelievable that a unit conceived on 11 Apr 40 could be put together in the south of England, heavy (highly classified) equipment located and assembled, then it & 62 servicemen transported to Unst in less than 4 weeks.  
The equipment provided for 3 TRU was similar to what we now call an AMES 9 Mk1 radar system. The radar would have operated on a frequency of about 43 MHz (wavelength about 7 metres) and a peak power of around 300Kw, provided by the Units own 2 Lister generators.  The picture below (kindly provided by Bob Jenner) gives a good idea of the layout and type of vehicles involved.
The personnel had varied backgrounds – there were 2 Volunteer Reserve Officers and 60 other ranks. Squadron Leader Mike Dean MBE has provided a complete nominal role of the unit which I have attached as Note 1. to this section. The Commanding Officer was Flight Lieutenant Len Pittendrigh, who had a significant role in a number of WWII radar establishments. This was his second RAF radar unit, having served in Suffolk before being put in charge of 3 TRU. The picture below is from after his time on Unst (I notice he has been promoted to Squadron Leader rank).

The site which had been surveyed for the unit on Unst, not far from the Baltasound pier, proved to be pretty useless with radar cover largely obscured by high ground – for those of you who know the area – the Heogs & the Keen of Hamar were in the way. Pittendrigh did the only sensible thing an experienced radar man would do – he decided to head for the nearest suitable high ground and hence the unit was erected on the Keen of Hamar. Theoretically, at about 300ft (89m), there should have been good radar coverage to the east & north-east in particular. There were problems in getting the equipment up the hill to the site – some of the zig zag tracks of the vehicles can still be seen. Once all the components were in position there were further problems. All of the radio equipment worked on batteries and it was discovered that the Coventry Climax powered battery charger had been damaged.  Without easy access to spares it took the CO a number of days to find a solution and even longer to make contact with Sumburgh for the first time. It took all hands to get the 70’ aerials erected and once up there were difficulties in earthing the radar system due to the solid rock below the surface layer. These problems delayed the start of radar operations until 28 May. Once operational it was found that the only serious screening was from 330° - 005°, where aircraft below 1,000 feet were not seen.
The Keen has a very barren landscape, mainly what could be termed serpentine debris. Today it is a reserve – the only known site of Edmonston's chickweed –
In this area things grow slowly and 72 years on the wheel ruts of 3 TRU’s trucks can still be seen:
On the ground there is still much evidence to indicate that the “transportable” unit was there – but subsequently left. Local folk tell me that the “L” shaped wall in the picture below was not there before the unit arrived and that servicemen planned to grow vegetables on site – perhaps the wall was erected to provide some shelter for crops or even constructed at the behest of NCOs or Officers in an attempt to keep the troops occupied.
Close to this wall and spelled out in stone on the surface are the letters “RAF” and “UNST” –

Two 70ft (21m) masts were erected; one for the Transmitter and one for the Receiver, each of these masts were anchored to the ground by four steel cables. Where the surface was suitable metal stakes may have been used but where the ground was unsuitable, anchor points were constructed – five of these points can still be seen:

There is something about wet cement that some people can’t resist. A larger picture of the last anchor point is shown below and it can be seen that the cement has the name of the unit “3 TRU 1940” and a skull & crossbones picked out in serpentine. A swastika has also been inscribed but for some reason it’s the wrong way round for the NAZI symbol – it is rather surprising to see it and I am sure it was added without the CO’s knowledge. Flight Lieutenant Pittendrigh was known to have worries about German sympathizers or even saboteurs amongst his personnel - these matters were taken very seriously early in the war.

The same anchor point has the names or initials of many of the men who served on the Unit, as can be seen in the next set of pictures. The name D Lamont is visible in the first - a look at Note 1 – the nominal roll - shows an AC2 Lamont, DL – a Wireless Operator - on the strength in 1940.
Two further examples:-
EDR is almost certainly AC1 Rhodes, ED – a Radar Operator and

OH would probably be LAC Hare, OF – Radar Mechanic.
It had been the intention for the men to live under canvas near the Baltasound Hall. The CO decided that more weather-proof accommodation was needed and sent his Adjutant to look for somewhere more suitable. It was discovered that the nearby Nord Hotel was unoccupied (though unfurnished) and it was immediately requisitioned.
Most of the men and the Adjutant moved into this building, which much later became Harry’s Shop & today is known as Ethel’s Shop. A small number stayed in the homes of local folk. Some huts were erected on the Keen for the use of on-duty personnel and the CO, Flight Lieutenant Pittendrigh, lived on site. The next photo shows what is possibly part of the foundations of one or more of these huts.
The Unit had brought rations from south, mainly dry and tinned, but the stock of cigarettes and rum had been plundered by civilian dockers en route. The shop nearest to the Nord Hotel, Millbrae, was soon emptied of provisions – Unst was a “dry” island so the rum could not be replaced locally. Personnel soon found that the boring diet could be supplemented with rabbits, fish & birds eggs.
During the period the Radar was on the Keen there was a manned Coastguard lookout hut close by. This was used throughout the war and indeed for long periods after the war ended. The lookouts were local men (mainly ex WW1 mariners), working as Auxiliary Coastguards. They worked 6 hour shifts whatever the weather. There must have been some interaction between them and the RAF personnel but, so far, I have found no details of it. The photo below shows the base of a later Coastguard hut, built on the site of the WWII construction:
The following Google Earth Image shows the layout of the site as it is today.

Operations. There is little data available about how the unit performed after it was set-up and what there is suggests it was not too successful. Reasons for this are not hard to find. What briefings they had must have been very sparse – who were they to contact on arrival and how, for example. Many of the men knew little about radar and the W/T operators would have been slow – it takes a long time to be proficient with Morse code and the necessity to encode messages would have delayed signal traffic considerably. Aerials were erected for R/T and W/T but bad interference was experienced. The communications aerials had to be re-erected out of line of sight from the Radar Transmitter aerial to minimise this problem. Working conditions for the Radar Operators would not pass any of today’s ergonomic tests. The display was about 4 or 5 inches (10-12cm) in diameter and at eye level.

Their work area would have been similar to that shown in the next picture.
The whole environment must have been totally alien to a large proportion of the men.
On 4 Jun 40 the Unit came under the operational Control of HQ 60 Group. It is at this stage I think that some confusion evolved regarding the history of the unit. I believe that is shortly after this date that the Unit changed its name from 3 TRU to Number 203 Mobile Radio Unit (MRU) – certainly it is 203 MRU when it left Unst.
There were a few equipment problems; for example, it took 3 days to replace a W/T valve –without it they would have been unable to pass information to higher authority by normal routes. When the W/T was working it was not particularly efficient, with reports being received late. An RDF (Radio Direction Finding) Chain Operational Report dated 27 Jun 40 stated “Dr Bower, Scientific Observer, at Wick Fighter Sector wrote:- “About noon today Unst reported that their W/T was now serviceable so they presumably have the valve they require. It may interest you to know that Unst were sending plots via Sumburgh and Donibristle (teleprinter) and that these plots arrived anything up to 11 hours late.”
I don’t feel that the Unit can be held particularly responsible for these late reports - I suspect it was more down to inexperience and a long-winded communications system. Donibristle is in Fife and Wick is 200miles from Unst so I’m not sure why this route was chosen or what could have been done at Wick if the reports had been almost instantaneous.
For those with an interest in radio, the frequencies which were allocated are in Note 2.

The actual performance of the radar was fairly poor, another RDF report at the beginning of Aug ’40 states that the average pickups were in the region of 20 miles and the maximum 40 miles. Once again we are talking about inexperienced personnel operating unfamiliar equipment without expert advice readily available. I’m sure that, given time, the performance would have improved.
A Squadron of Gloster Gladiators had been based at Sumburgh (then a grass airfield), since early in 1940, but there were no modern fighters based in Shetland until a Flight of Hurricane Mk 1’s  was detached to Sumburgh (70 miles south of the Keen of Hamar) in the middle of the year. I believe that a controller accompanied this deployment but, with the poor ranges achieved from the Keen, the radar cover would have been inadequate to produce effective results until the performance of the Unit could be improved.
The Royal Navy had a fully operational Coastal Defence Radar, based at Sumburgh from Sep ’39 onwards, but its main purpose was to monitor surface movements to the south. Later in the war this radar was used to control a number of interceptions of German aircraft.
Defence of the Unit
There is anecdotal evidence of a machine gun post just to the south-east of the radar masts but I haven’t been able to find any sign of it. The area is actively farmed, being outside the Nature Reserve and this has possibly destroyed any evidence of it. The Unit had guards on duty, as can be seen from this copy of Daily Routine Orders (DRO’s even in those days), dated 18 Jul 40 – the original document was found by my wife’s grandfather, John Sutherland, who was one of the Coastguard lookouts. According to the CO after the War, none of his men had fired more than 3 rounds in training before their deployment to Unst.

To provide another line of defence an armed trawler was stationed at Baltasound. Nowadays an “armed trawler” can sound insignificant but the Royal Navy operated a number of different classes of vessel which came into this category – many used to bolster harbour defences. Between 1939 and 1945, for example, 197 “Isles” Class armed trawlers were built for the RN and each of these vessels could carry a 12 pounder and 3 or 4 x 20mm Oerlikon AA guns. I don’t know what class of vessel was deployed to Baltasound but I’m sure that the airmen were glad of its presence.   Initially communications between the trawler and the Unit were visual – a mast especially for this purpose being erected on the Keen and, in darkness, a signal lamp was used. The mast & signal lamp would have been used for passing air raid warnings.
In extremis, the sensitive equipment had been rigged with explosive and could have been destroyed had the Germans landed on the island. Radar was highly classified and the thought of it falling into enemy hands was of great concern. A further indication of how Shetland was considered to be in the front line at this stage in the war can be seen at RAF Scatsa. Scatsa, the most northerly RAF airfield in UK, was built near Sullom Voe specifically for fighter aircraft to provide cover for the flying boat base. The first 3,600 ft runway was completed in Apr ’40 but no fighters based there at the time the radar was on the Keen of Hamar. It was the only airfield in Scotland built with pipe mines laid at 50 yd intervals along the runway and taxi-ways. These mines would have been used to destroy the facilities should the Germans invade Shetland – the threat was considered that seriously.
Visitors and the Local Population.   There were official visits to the site during the short life of the Unit. Certainly a Group Captain and an Admiral arrived on Unst for separate formal visits – both by Supermarine Walrus Amphibians from Sullom Voe - landing at Baltasound. I believe these aircraft were operated by No 700 Sqn Fleet Air Arm. Their arrival, other than the disruption to normal life, would have had little operational effect on the personnel on the Keen. Fortunately AES4 on Saxa Vord and RAF Skaw on Lamba Ness were under construction, so there were other things for them to do.
The effect of the Unit on the local population is not recorded officially but there are many anecdotes/stories and some of them have been recounted by my late mother-in-law Lexie McMeechan (Sutherland as she then was).  Lexie would have been 17 when the Unit landed and she lived about 200yds from the pier and less than a mile from the site on the Keen of Hamar. A few of the stories are summarised below.
1.      When the Unit landed at Baltasound the Unst folk, who were more used to seeing dark blue naval uniforms, saw light blue uniforms with eagle badges. They thought it was a German landing force and made themselves scarce! Flight Lieutenant Pittendrigh expressed surprise at the time that no locals appeared at the scene of the landing to see what was going on.
2.      Later a local asked one of the airmen how they kept warm in their huts on the Keen without range or a peat fire. When the airman said he had an “electric” fire & tried to explain how it worked there was disbelief and suspicion that someone’s leg was being pulled (no mains electricity on Unst until more than 15 yrs later)
3.      RAF Sullom Voe, with its flying boats, was a very active RAF Unit at this stage of the War. It had a very credible station band and it was decided to send the musicians up to Unst to hold a Dance in the Baltasound Hall. The musicians duly arrived by sea at Baltasound on 3 Jul 40 and the dance took place that night. The local population had a fairly high percentage of females – many of the men were away with the Services, Merchant Navy or fishing. The isles were used to dances going on into the night, weddings and significant events being celebrated – one would think it was the ideal situation for the young servicemen. However, Unst had no mains power so the music people were used to came from a fiddle or two, possibly an accordion & maybe a piano in the hall. The ladies only knew reels and jigs etc – the Band played foxtrots & tangos etc – very little dancing took place but perhaps there was some fraternisation.
The End.  On 1 Aug 40 the Unit received a signal which said “Close down. Prepare to embark by August 4th.”
This message took personnel by surprise and Flight Lieutenant Pittendrigh refused to take action on it until he had sought confirmation. After much hard work the Unit had been operational for just a few weeks and was beginning to fulfil the role for which it had been deployed.
After 3 months on the island and even less time operational, the Unit was shut-down – why?  There are a number of theories – the first involves the threat of invasion and the compromise of classified equipment.
The theory that the Germans might land on Unst and capture this sensitive equipment is highly attractive – the allied raid on Bruneval early in 1942, when secret German radar equipment was seized, shows what might have been accomplished. Personally, I don’t subscribe to this idea – the construction of AES4 on Saxa Vord and the building of RAF Skaw continued. Many knowledgeable radar personnel were left on Unst after the Unit departed – people and equipment just as valuable to a German raiding party.  Besides, the naval Coastal Defence U boat radars (AES2 & AES3) on Fair Isle were left in situ, despite the fact that they were probably just as vulnerable to intruders.
Another possibility, if the Unit had been deployed to help cover the resupply of the allied expeditionary force in Norway, then that mission was complete. The British/French force was withdrawn from Norway early in June, just after the Norwegian surrender.
The theory I give most credence to is that based on a change in the perceived threat. On 10 May 40 Germany invaded France and the Low Countries and met with quick success, advancing very rapidly. The evacuation at Dunkirk took place between 26 May and 4 Jun 40. Once again the main threat would appear to be to the Home Counties – perhaps the army wanted the gun-laying equipment or perhaps the now relatively experienced radar personnel would have been of better use on radar sites further south. To put it in perspective – the Battle of Britain had entered its first phase and radar was playing an important role. The RAF and MOD recognise 10 Jul 40 as the start of the battle with the onset of the “Kanalkampf” – the Luftwaffe attacking coastal shipping and its naval escorts in the English Channel. The Germans achieved much success, sinking a number of vessels including several destroyers. Perhaps the planners decided that experienced radar personnel would be of better use elsewhere!
Could it be possible that the politicians and the military believed that the defence of the Home Counties was more important than the defence of the Northern Isles?
After leaving Unst the Unit was disbanded.
What did 3TRU/203MRU Achieve.  It would be simple to say that the deployment to Unst was a waste of resources at the time of a major threat to the country. That would be simple – but untrue!
Radar was new and the thought of a transportable radar unit an important, but largely untried concept. The Unit was quickly formed and moved fairly rapidly to its operational location. Yes, not everything went well, but the experience of the operation was invaluable to future “mobile” and static radars.  The siting problems, the communication problems, the command problems etc – there was a steep learning curve, which helped later operations. The men in this deployment were largely untrained when they arrived but, when the Unit was disbanded, they were posted to other radar units with invaluable experience. No one left Unst under the cloud of failure – they were welcomed back onto mainland UK as “experienced veterans”. One of the airmen, Wally Morton, arrived on Unst as an AC2 Radar Operator (under training); on closure of the Unit he was posted to RAF Bawdsey. Later on in he was posted to other radar sites including Hopton & Stoke Holy Cross. A picture of the late Wally Morton taken in 1940, just after he arrived at Bawdsey is below:
The letter reproduced below was sent to Len Pittendrigh just after he left Unst by his superior, the CO of RAF Sullom Voe Group Captain Croke, it indicates his efforts on Unst had been appreciated. The fire referred to in the letter was in the Nord Hotel and had been extinguished by Pittendrigh and his men just before they left the island. The Dr Saxby, also referred to in the letter, was the Unst GP – his son, Stephen, joined the RAF, served at Sullom Voe in WWII and later worked as an MT Fitter in the RAF Saxa Vord MT Section.
Flight Lieutenant Pittendrigh went on to promotion and to play a significant role in the WWII radar story. Amongst other postings he commanded the CH site at RAF Worth Matravers and worked on the identification and location of enemy jamming sites when he was at Malvern
The departure must have mystified the local population but, there again, so did the arrival. Were any of them concerned? Who knows! – no civilians on Unst would have been involved in strategic or tactical decision making and, besides, there were plenty of other things happening on the island – the naval radar on Saxa Vord, RAF Skaw, Walrus Amphibians and the occasional Catalina/Canso flying boat at Baltasound, the Local Defence Force Volunteers and an RAF High Speed Rescue Launch based at the pier – plenty of distractions!
The RN radar site on Saxa Vord, Admiralty Experimental Station No4, became operational in Sep 1940; just weeks after 203MRU left the island.
Note 1. Nominal Role 3TRU/203MRU
Note 2. Radio Frequencies
2150 Kc/s W/T - Wick/Unst for Plotting
6470 Kc/s R/T Lerwick/Graven/Unst for Plotting (including contact with patrols and to Naval Walrus aircraft stationed at Baltasound in emergency.

3085 Kc/s W/T - Graven/Unst for Admin or code traffic (Graven was where the Admin & Domestic Sites for RAF Sullom Voe were located)
Sources & Acknowledgements
Letters between Lexie McMeechan and Wally Morton
The Keen of Hamar in 1940: Unst’s First Radar Station by David Waters
Scatsa Airfield (Revisited), Shetland by Terry Mayes
AVIA 7/439 - RDF Chain Operational Reports
AVIA 7 - 709 GM E69 stamped AMRE 2 July 1940 - Report on Unst station No 3 TRU

The Unst Heritage Centre
Bob Jenner
Ian Brown