Kilnahirk's best kept secret.
Sometime in the late 1930's a government building and its infrastructure arrived among the farms and green pastures which make up the town land of Ballyhanwood. It was one of those places which everyone in the loval area was aware of, but that it was. From the beginning the Radio Station has been associated with all sorts of rumours and wild tales. This account will reveal only part of the true story about the role it played during the second world war. The fine detail is still locked up in top secret government files.
This article was dedicated to the memory of Captain Joe Banham the officer in charge at Gilnahirk during the war years. We remember also the men and women who worked at Gilnahirk, but their names remain a mystery to this day, because those who worked at this station never talked about their work, neither during nor after the war. It was a part of WW-2 history that each and everyone took to their graves.
During the run up to WW-2 the General Post Office established a radio station on the Castlereagh Hills overlooking Belfast. The site consisted of a few wooden and nissan huts which were surrounded by a considerable number of very tall telepraph poles dotted about the adjoining fields. These poles were linked together with overhead wire and formed the aerial network which was used to intercept the radio traffic of the time. The wooden huts served a number of roles, but one hut would have contained the main radio room. This consisted of eighteen banks of American HRO receivers. These receivers were the Rolls Royce of their day and no signal escaped the fine tuning of an HRO receiver.
This article was dedicated to the memory of Captain Joe Banham the officer in charge at Gilnahirk during the war years. We remember also the men and women who worked at Gilnahirk, but their names remain a mystery to this day, because those who worked at this station never talked about their work, neither during nor after the war. It was a part of WW-2 history that each and everyone took to their graves.
During the run up to WW-2 the General Post Office established a radio station on the Castlereagh Hills overlooking Belfast. The site consisted of a few wooden and nissan huts which were surrounded by a considerable number of very tall telepraph poles dotted about the adjoining fields. These poles were linked together with overhead wire and formed the aerial network which was used to intercept the radio traffic of the time. The wooden huts served a number of roles, but one hut would have contained the main radio room. This consisted of eighteen banks of American HRO receivers. These receivers were the Rolls Royce of their day and no signal escaped the fine tuning of an HRO receiver.
HRO receiver.
During the establishment of this station a Top Secret Marconi Adcock Direction Finding facility was placed into an all metal tank and then the whole thing was buried just below the ground some distance from the main collection of wooden huts. Four thirty feet high telegraph poles were placed one at each corner of this underground strcture.
The Adcock antenna is an antenna array consisting of four equidistant vertical elements which can be used to transmit or receive directional radio waves.
The Adcock array was invented and patented by British engineer Frank Adcock and since his August 1919 British Patent No. 130,490, the 'Adcock Aerial' has been used for a variety of applications, both civilian and military. Although originally conceived for receiving low frequency (LF) waves, it has also been used for transmitting, and has since been adapted for use at much higher frequencies, up to ultra high frequency (UHF).
In the early 1930s, the Adcock antenna (transmitting in the LF/MF bands) became a key feature of the newly created radio navigation system for aviation. The low frequency radio range (LFR) network, which consisted of hundreds of Adcock antenna arrays, defined the airways used by aircraft for instrument flying. The LFR remained as the main aerial navigation technology until it was replaced by the VOR system in the 1950s and 1960s.
The Adcock antenna array has been widely used commercially, and implemented in vertical antenna heights ranging from over 40 m (130 feet) in the LFR network, to as small as 13 cm (5 inches) in tactical direction finding applications (receiving in the UHF band).
Diagram from Adcock's 1919 patent, depicting a four-element monopole antenna array; active antenna segments are marked in red.
Frank Adcock originally used the antenna as a receiving antenna, to find the azimuthal direction a radio signal was coming from in order to find the location of the radio transmitter; a process called radio direction finding.
Prior to Adcock's invention, engineers had been using loop antennas to achieve directional sensitivity. They discovered that due to atmospheric disturbances and reflections, the detected signals included significant components of electromagnetic interference and distortions: horizontally polarized radiation contaminating the signal of interest and reducing the accuracy of the measurement.
Adcock—who was serving as an Army officer in the British Expeditionary Force in wartime France at the time he filed his invention—solved this problem by replacing the loop antennas with symmetrically inter-connected pairs of vertical monopole or dipole antennas of equal length. This created the equivalent of square loops, but without their horizontal members, thus eliminating sensitivity to much of the horizontally polarized distortion. The same principles remain valid today, and the Adcock antenna array and its variants are still used for radio direction finding.
The Adcock antenna is an antenna array consisting of four equidistant vertical elements which can be used to transmit or receive directional radio waves.
The Adcock array was invented and patented by British engineer Frank Adcock and since his August 1919 British Patent No. 130,490, the 'Adcock Aerial' has been used for a variety of applications, both civilian and military. Although originally conceived for receiving low frequency (LF) waves, it has also been used for transmitting, and has since been adapted for use at much higher frequencies, up to ultra high frequency (UHF).
In the early 1930s, the Adcock antenna (transmitting in the LF/MF bands) became a key feature of the newly created radio navigation system for aviation. The low frequency radio range (LFR) network, which consisted of hundreds of Adcock antenna arrays, defined the airways used by aircraft for instrument flying. The LFR remained as the main aerial navigation technology until it was replaced by the VOR system in the 1950s and 1960s.
The Adcock antenna array has been widely used commercially, and implemented in vertical antenna heights ranging from over 40 m (130 feet) in the LFR network, to as small as 13 cm (5 inches) in tactical direction finding applications (receiving in the UHF band).
Diagram from Adcock's 1919 patent, depicting a four-element monopole antenna array; active antenna segments are marked in red.
Frank Adcock originally used the antenna as a receiving antenna, to find the azimuthal direction a radio signal was coming from in order to find the location of the radio transmitter; a process called radio direction finding.
Prior to Adcock's invention, engineers had been using loop antennas to achieve directional sensitivity. They discovered that due to atmospheric disturbances and reflections, the detected signals included significant components of electromagnetic interference and distortions: horizontally polarized radiation contaminating the signal of interest and reducing the accuracy of the measurement.
Adcock—who was serving as an Army officer in the British Expeditionary Force in wartime France at the time he filed his invention—solved this problem by replacing the loop antennas with symmetrically inter-connected pairs of vertical monopole or dipole antennas of equal length. This created the equivalent of square loops, but without their horizontal members, thus eliminating sensitivity to much of the horizontally polarized distortion. The same principles remain valid today, and the Adcock antenna array and its variants are still used for radio direction finding.
All this work was carried out by the Royal Corps of Signals and the GPO radio department. The Belfast electricity company supplied a transformer to the site, but the main cable feed for that transformer had to be buried below the ground incase it caused any interference to the signal reception. The GPO also provided an underground high grade telephone cable which allowed the station to be part of a much bigger wartimecommunication network.
Local farmers supplied the radio station with milk and vegetables. On Sunday mornings of the duty solders were marched down the road to Gilnahirk Presbyterian Church.
Before the Belfast Blitz if not all the radio operators lived in military accomodation within the city. After the Blitz, a local farmer was asked to convert a big wooden chicken house into a brrack block for most of the operators. The remainder boarded with local people in the Gilnahirk area. Through time additional nissan huts were added to the site along with a NAAFI. The local bus service to Manns Corner had been around for some years, but with the coming of the radio station the timetable was adjusted to fit the needs of the station. As the war progressed wooden poles were replaced with steel radio masts and older out of date equipment was continually updated.
The radio signal was the internet of the war. It allowed people, military units and government departments to keep in touch when they were traveling. The GPO were the guardians of this technology and under an act of parliament they had to police the airwaves. Anyone caught operating a radio set without approval was up to no good and it was the job of the GPO to put them out of business. When Gelnahirk was officially switched on it had the ability to listen to all radio transmissions and it also had the ability with the assistance of one or two locations within the UK to locate the position of those transmissions.
The government of the day believed that Germany and her allies would send secret agents into the UK to spy and report back on the various aspects of our wartime planning. When all this started there was a serious lack of trained radio operators to listen in on the many frequencies available to the enemy. To assist in this mammoth task the Government secretly selected and recruited hundreds of amateur radio enthusiasts to listen in on given frequencies. Here in Northern Ireland our amateurs had their part to play and every transmission they heard was recorded on paper logs giving the date, the time, the frequency and the message. These amateurs were known as the Radio Security Service or RSS for short. Sometimes only part of a message was received, but everything was recorded and sent to PO Box 25 Barnet. Please remember that each of these amateurs had signed the Official Sectrets Act and most if not all in Northern Ireland have gone to their graves without revealing their secret wartime role. It was drummed into them that they must never ever talk about their work, not even to family or other radio amateurs.
At PO Box 25 all these reports were crossed referenced and checked. Part of a message which was missed by a listener in Scotland may well have been heard by someone in Southhampton, the Isle of Man or county Down. It was just like putting a jigsaw together, a piece here and a piece there, but over time a picture began to emerge of what was going on. If something of interest or importance to our war effort appeared it was handed over to the professionals.
The frequency of special interest message was passed on to a fulltime operator. He tuned his HRO set and waited. Please understand that we are not listening to a constant stream of information. This was a twentyfour seven watch and there may have been hours, even days, when nothing was heard, but our operator had to be ready when suddenly without warning that frequency came to life with the tapping of a Morse key.
All messages which were heard and recorded by both the amateurs and professionals were simply a jumble of letters. Normally sent in groups of five letters. This was ot a message in plain readable text. It was encoded so that only the sender and the oficial receiver would have known the key to breaking the code and reading the text of the message. We now bring two very familiar wartime names into our story. 'Bletchley Park' and 'Enigma'. The work of gilnahirk which had started modestly under the control of the GPO was now in the realms of MI-6 and was part of Special Communication Unit Three The first military guards around the site were the Inniskillings and the Royal Ulster Rifles, but by 7 Febriary 1942 the Blue Caps of the Royal Military Police were in charge and everything at the Radio Station was air tight. The building and its content were considered a valuable point and had become one of the most secure and secret places in the nation. The fine details of what Gilnahirk acually did are still locked away in top-secret government files and this current generation may never read what went on. It is true to say that even the people who worked at Gilnahirk did not know what they were doing; such was the way in which our intelligence organization worked. The information of a Secret, Top-Secret and Ultra-Secret nature would have been known to only a very few individuals. It was the old rule of 'A need to know'
In concluding the story of Gilnahirk's wartime role I will give a considered example of the war against Nazi Germany. The Battle of the Atlantic was very close by with Glasgow, Liverpool, Belfast and Derry ready to send or receive the merchant navy convoys.
A member of the Radio Security Service picks up a part of a U-Boat message looking for a convoy. This frequency has now been passed on to Gilnahirk and is monitored around the clock.Daus pass and nothing more is heard, but suddenly and without warning another message is overheard by the HRO set operator who has been patiently waiting. At this point he does a number of things:
1. he starts to write the message down, letter by letter.
2. At the same time he alerts his controller, who will also listen in and make a copy.
3. Finally he sends the very same radio signal down a telephone line to Beaumanor central control in England.
(Ik denk dat deze operator het signaal meteen naar Beaumanor doorstuurde, gezien de korte duur van de berichtgeving vanuit de onderzeeboot. Men wist ook wel dat men uitgepeild zou worden.)
The Adcock Direction Finding equipment at Gilnahirk was also manned twentyfour seven just like the rest of the site. The difference, the operator was sitting in a metal tank, just below the surface of the ground on your eight hours shift. Once again, hours and days may have passed with nothing to do but wait. Suddenly central control at Beaumanor alerts the operator to task in hand. The signal frequency which has been received just yards away in the wooden hut down the field, is now coming to you over a telephone line via England and he can hear it loud and clear in the right hand ear piece of the headset. As quickly as possible he starts to hunt for the same signal using a Goiniometer and a HRO receiver. Within seconds the signal is loud and clear in the lefthand ear piece of the headset. The compass bearing can now be read from the dial in front of the operator. Using a morse key the bearing is send to Beaumanor on a second dedicated telehone line. So quick and skilled were the DF operators that it took them only seconds to get a bearing on the transmission.
This Direction Finding task would also have been carried out at the same time in other locations within the UK. By sending the signal via telephone line from Gilnahick to beaumanor , it is possible to send the same signal back to Gilnahirk on a separate telephone line and on to other DF sites at the same time. With the bearing readings of two or more DF sites it was possible to quickly pinpoint the location of the transmission on a very large map in the Beaumanor plotting room. The U-Boat is now on the map and the convoys will be informed about its position and rerouted. The route of the submarine is further plotted by receiving further radio transmissions. These transmissions will in turn reveal other U-Boats and support vessels in the Atlantic. Over time a complete picture of who is in the Atlantic is plotted on the map. The type of U-Boat is known, also its speed, its range and if the signal is lost there is still a possibility to guess where it might be. (Men kon het type boot pas bepalen wanneer de gebruikte Enigma codering gekraakt was)
In time the hunter became the hunted and could be destroyed. The radio operator on a U-Boat would have a way of handling his morse key, this is called a finger print. A good operator at Gilnahirk could tell if he was listening to the same German WT operator even though the frequency may have changed.
This is just one example of the important role of the few huts, a collection of telegraph poles and a metal tank in the town land of Ballyhanwood played in the war against Nazi Germany.
The wartime site is gone and the town land of Ballyhanwood has returned to green pastures.
Source: benvista.
Article ID: A8533811
Date: 14-01-2006
THE Y-SERVICE.
The "Y" service was a network of British signals intelligence collection sites, the Y-stations. The service was established during the First World War and used again during the Second World War. The sites were operated by a range of agencies including the Army, Navy and RAF, and the Foreign Office (MI6 and MI5). The General Post Office and the Marconi Company provided some receiving stations, ashore and afloat. There were more than 600 receiving sets in use at Y-stations during the Second World War.
The "Y" name derived from Wireless Interception (WI). The stations tended to be one of two types, for intercepting the signals and for identifying where they were coming from. Sometimes both functions were operated at the same site, with the direction finding (D/F) hut being a few hundred metres from the main interception building to minimise interference. The sites collected radio traffic which was then either analysed locally or, if encrypted, passed for processing initially to the Admiralty Room 40 in London and then during World War II to the Government Code and Cypher School at Bletchley Park in Buckinghamshire.
In the Second World War a large house called "Arkley View" on the outskirts of Barnet (now part of the London Borough of Barnet) acted as a data collection centre, where traffic was collated and passed to Bletchley Park; it also housed a Y station. Much of the traffic intercepted by the Y stations was recorded by hand and sent to Bletchley by motorcycle couriers, and later by teleprinter over Post Office landlines. Many amateur radio operators supported the work of the Y stations, being enrolled as "Voluntary Interceptors".
The term was also used for similar stations attached to the India outpost of the Intelligence Corps, the Wireless Experimental Centre (WEC) outside Delhi.
Specially constructed Y stations undertook high-frequency direction finding (D/F) of wireless transmissions. This became particularly important in the Battle of the Atlantic where locating U-boats was vital. Admiral Dönitz told his commanders that they could not be located if they limited their wireless transmissions to under 30 seconds, but skilled D/F operators were able to locate the origin of their signals in as few as six seconds.
The design of land-based D/F stations preferred by the Allies during the Second World War was the U-Adcock system, where a small operators' hut was surrounded by four 10 ft-high (3.0 m) vertical aerial poles, usually placed at the points of the compass. Aerial feeders ran underground, surfaced in the centre of the hut and were connected to a direction finding goniometer and a wireless receiver, that allowed the bearing of the signal source to be measured. In the UK some operators were located in an underground metal tank. These stations were usually in remote places, often in the middle of farmers' fields. Traces of Second World War D/F stations can be seen as circles in the fields surrounding the village of Goonhavern in Cornwall.
Y station sites in Britain:
Beachy Head, Sussex
Beaumanor Hall, near Loughborough, Leicestershire (operated by the Army)
Beeston Hill, Beeston Regis, Norfolk
Bishop's Waltham, Hampshire (operated by the Army)
Brora, Sutherland
RAF Canterbury, Kent
RAF Cheadle, Cheadle, Staffordshire
RAF Chicksands, Bedfordshire (operated by the RAF)
RAF Clophill, Bedfordshire
Cromer, Norfolk
Forest Moor, near Harrogate (operated by the Army)
G.P.O. Transatlantic Radiophone Station Kemback, near Cupar, Fife
Denmark Hill, Camberwell (operated by the Metropolitan Police and General Post Office (GPO) for the Foreign Office)
Met Office Dunstable, Bedfordshire
Felixstowe, Suffolk
Gilnahirk, Belfast
Gorleston, Norfolk
Hall Place, Kent
Harpenden, Hertfordshire (Army, No. 1 Special Wireless Group)
Hawklaw, Fife
HMS Flowerdown, Winchester, Hampshire
HMS Forest Moor, Harrogate, Yorkshire
Kedleston Hall, Derbyshire
RAF Kingsdown, Hollywood Manor, West Kingsdown, Kent
RAF Monks Risborough, Monks Risborough, Buckinghamshire
Knockholt, Kent (run by the Foreign Office for non-Morse radiotelegraphy signals)
Markyate, Hertfordshire (operated by the Army)
Newbold Revel, RAF 'Y' Service Secret Intelligence and German Telephony Communications Base, Warwickshire.
North Walsham, Norfolk
Sandridge, Hertfordshire (operated by the Foreign Office)
Saxmundham, Suffolk
Scarborough, Yorkshire (operated by the Royal Navy)
Shenley Brook End Milton Keynes (operated by the Army)
South Walsham, Norfolk
Southwold, Suffolk
Stockland Bristol, near Bridgwater, Somerset
Stockton-on-Tees, Cleveland
HMS Ventnor, Rew Down, Isle of Wight
RAF Waddington, Lincolnshire
Whitchurch, Shropshire in The Old Rectory, Claypit Street (operated by the Foreign Office)
Wick (operated by the RAF)
Wincombe, Donhead St Mary, Wiltshire (operated by the GPO for the Foreign Office)
Withernsea, East Yorkshire from a pub, the St. Leonards, now known as Captain Williams
Woodcock Hill, Sandridge, St Albans
Source: Wikipedia.
Listening to the Enemy: Ventnor’s Y Station.
Most people who live in Ventnor know about the WWII radar station on top of St Boniface Down, which anchored the western end of the original
Chain Home early warning system and was the reason for the heavy German bombing raids that damaged many parts of the town.
What fewer people know is that Ventnor was home to part of another, even more secret system that was critical to the Allied victory. It was the
site – the only one on the island -- of one of the twenty or so Royal Navy ‘Y stations’ (from ‘WI’ for Wireless Interception) that intercepted and
located enemy transmissions and passed the information on to Portsmouth HQ and Bletchley Park (‘Station X’) for decoding. If the radar
stations were the ‘eyes’ of the war effort, the Y stations were the ‘ears’.
The headquarters of the Ventnor Y Station was 'The Heights' on Whitwell Road, a large private house (later a hotel, demolished in 1989 and
now the site of the Foxhills estate), with additional accommodation at a nearby house called Chilonga. Manned by Wrens from the WRNS
Special Duties (SD) Service, it mostly intercepted messages in the German Naval Enigma code, which was broken by Bletchley Park. Reading
these messages was critical for winning the Battle of the Atlantic against the U-boats.
Other messages, in a simpler, more easily broken code, were sent by local naval facilities, harbour masters and lighthouses on the French coast
and in the Channel Islands. By knowing which lighthouses were to be turned on and when, the Royal Navy could deduce if German E-boats
were planning a sortie or the movements of coastal convoys. The failure to pick up any such messages on the night before D-Day in 1944 was
an important sign that the invasion had achieved the necessary surprise.
As important as intercepting the messages was, knowing where they came from was equally valuable. Some Y Stations, such as Ventnor, had
DF (Direction Finding) facilities, usually a 30-foot wooden tower on a concrete base, incorporating a hut with a swivelling antenna. If two or more
stations could get a bearing on an enemy transmissions, the sending ship could be precisely located. A skilled operator could pin down the
bearing in as little as six seconds.The Ventnor tower stood on Rew Down, above the Heights. Such towers had to be a few hundred yards from the main receiving station to avoid interference. Most such towers were manned by a single person, and it could be quite scary at night under strict blackout conditions. At Ventnor, the operator had to sit with her back to the door, which could be even more nerve-wracking.
On 15 July 1944 the tower was damaged by a V1 ‘doodlebug’ flying bomb, which also blew out windows of several houses along Whitwell Road. A large crater about 100 feet from the site of the tower is still visible. The Y station wasn’t the target – V1s were accurate only to within a few miles at best. The six buzz bombs that exploded on the Island during the course of the war were all probably aimed at Portsmouth or Southampton! It was sheer bad luck that this one hit where it did, so close to the DF tower.
The tower was repaired, but the Ventnor Y station ceased operation by September 1944, presumably because Allies now controlled the parts of
France and the Channel it monitored. The tower remained standing until 1948 or 1949, but all that now remains is an octagonal brick ‘pillbox’
just below the V54 bridle path, with a concrete foundation and external concrete pads for the wooden supports. Its nature was a mystery until
quite recently: some people did remember the tower, but thought it was a transmitter, part of the radar station, or an observation post. Most
investigators weren’t even aware the tower had been there, and thought the brick structure was likely to have been an anti-aircraft gun
emplacement or the housing for a generator for a searchlight.
A few years ago, members of the Isle of Wight Industrial Archaeology Society began an investigation of the structure, identifying it as a DF
tower. Their findings were instrumental in the Grade II listing of the site by English Heritage in October last year. It is one of the best preserved
Y station towers nationally and possibly only one of two that retain their brick blast wall.
Jeff Mazo, Ventnor & District Local History Society. Main sources: Historic England, “Remains of a Direction Finding (D/F) tower, Ventnor YStation” List entry number 1427450, 26 October 2015; Gwendoline Page, ed., They Listened in Secret (2003).
weggum.com
Local farmers supplied the radio station with milk and vegetables. On Sunday mornings of the duty solders were marched down the road to Gilnahirk Presbyterian Church.
Before the Belfast Blitz if not all the radio operators lived in military accomodation within the city. After the Blitz, a local farmer was asked to convert a big wooden chicken house into a brrack block for most of the operators. The remainder boarded with local people in the Gilnahirk area. Through time additional nissan huts were added to the site along with a NAAFI. The local bus service to Manns Corner had been around for some years, but with the coming of the radio station the timetable was adjusted to fit the needs of the station. As the war progressed wooden poles were replaced with steel radio masts and older out of date equipment was continually updated.
The radio signal was the internet of the war. It allowed people, military units and government departments to keep in touch when they were traveling. The GPO were the guardians of this technology and under an act of parliament they had to police the airwaves. Anyone caught operating a radio set without approval was up to no good and it was the job of the GPO to put them out of business. When Gelnahirk was officially switched on it had the ability to listen to all radio transmissions and it also had the ability with the assistance of one or two locations within the UK to locate the position of those transmissions.
The government of the day believed that Germany and her allies would send secret agents into the UK to spy and report back on the various aspects of our wartime planning. When all this started there was a serious lack of trained radio operators to listen in on the many frequencies available to the enemy. To assist in this mammoth task the Government secretly selected and recruited hundreds of amateur radio enthusiasts to listen in on given frequencies. Here in Northern Ireland our amateurs had their part to play and every transmission they heard was recorded on paper logs giving the date, the time, the frequency and the message. These amateurs were known as the Radio Security Service or RSS for short. Sometimes only part of a message was received, but everything was recorded and sent to PO Box 25 Barnet. Please remember that each of these amateurs had signed the Official Sectrets Act and most if not all in Northern Ireland have gone to their graves without revealing their secret wartime role. It was drummed into them that they must never ever talk about their work, not even to family or other radio amateurs.
At PO Box 25 all these reports were crossed referenced and checked. Part of a message which was missed by a listener in Scotland may well have been heard by someone in Southhampton, the Isle of Man or county Down. It was just like putting a jigsaw together, a piece here and a piece there, but over time a picture began to emerge of what was going on. If something of interest or importance to our war effort appeared it was handed over to the professionals.
The frequency of special interest message was passed on to a fulltime operator. He tuned his HRO set and waited. Please understand that we are not listening to a constant stream of information. This was a twentyfour seven watch and there may have been hours, even days, when nothing was heard, but our operator had to be ready when suddenly without warning that frequency came to life with the tapping of a Morse key.
All messages which were heard and recorded by both the amateurs and professionals were simply a jumble of letters. Normally sent in groups of five letters. This was ot a message in plain readable text. It was encoded so that only the sender and the oficial receiver would have known the key to breaking the code and reading the text of the message. We now bring two very familiar wartime names into our story. 'Bletchley Park' and 'Enigma'. The work of gilnahirk which had started modestly under the control of the GPO was now in the realms of MI-6 and was part of Special Communication Unit Three The first military guards around the site were the Inniskillings and the Royal Ulster Rifles, but by 7 Febriary 1942 the Blue Caps of the Royal Military Police were in charge and everything at the Radio Station was air tight. The building and its content were considered a valuable point and had become one of the most secure and secret places in the nation. The fine details of what Gilnahirk acually did are still locked away in top-secret government files and this current generation may never read what went on. It is true to say that even the people who worked at Gilnahirk did not know what they were doing; such was the way in which our intelligence organization worked. The information of a Secret, Top-Secret and Ultra-Secret nature would have been known to only a very few individuals. It was the old rule of 'A need to know'
In concluding the story of Gilnahirk's wartime role I will give a considered example of the war against Nazi Germany. The Battle of the Atlantic was very close by with Glasgow, Liverpool, Belfast and Derry ready to send or receive the merchant navy convoys.
A member of the Radio Security Service picks up a part of a U-Boat message looking for a convoy. This frequency has now been passed on to Gilnahirk and is monitored around the clock.Daus pass and nothing more is heard, but suddenly and without warning another message is overheard by the HRO set operator who has been patiently waiting. At this point he does a number of things:
1. he starts to write the message down, letter by letter.
2. At the same time he alerts his controller, who will also listen in and make a copy.
3. Finally he sends the very same radio signal down a telephone line to Beaumanor central control in England.
(Ik denk dat deze operator het signaal meteen naar Beaumanor doorstuurde, gezien de korte duur van de berichtgeving vanuit de onderzeeboot. Men wist ook wel dat men uitgepeild zou worden.)
The Adcock Direction Finding equipment at Gilnahirk was also manned twentyfour seven just like the rest of the site. The difference, the operator was sitting in a metal tank, just below the surface of the ground on your eight hours shift. Once again, hours and days may have passed with nothing to do but wait. Suddenly central control at Beaumanor alerts the operator to task in hand. The signal frequency which has been received just yards away in the wooden hut down the field, is now coming to you over a telephone line via England and he can hear it loud and clear in the right hand ear piece of the headset. As quickly as possible he starts to hunt for the same signal using a Goiniometer and a HRO receiver. Within seconds the signal is loud and clear in the lefthand ear piece of the headset. The compass bearing can now be read from the dial in front of the operator. Using a morse key the bearing is send to Beaumanor on a second dedicated telehone line. So quick and skilled were the DF operators that it took them only seconds to get a bearing on the transmission.
This Direction Finding task would also have been carried out at the same time in other locations within the UK. By sending the signal via telephone line from Gilnahick to beaumanor , it is possible to send the same signal back to Gilnahirk on a separate telephone line and on to other DF sites at the same time. With the bearing readings of two or more DF sites it was possible to quickly pinpoint the location of the transmission on a very large map in the Beaumanor plotting room. The U-Boat is now on the map and the convoys will be informed about its position and rerouted. The route of the submarine is further plotted by receiving further radio transmissions. These transmissions will in turn reveal other U-Boats and support vessels in the Atlantic. Over time a complete picture of who is in the Atlantic is plotted on the map. The type of U-Boat is known, also its speed, its range and if the signal is lost there is still a possibility to guess where it might be. (Men kon het type boot pas bepalen wanneer de gebruikte Enigma codering gekraakt was)
In time the hunter became the hunted and could be destroyed. The radio operator on a U-Boat would have a way of handling his morse key, this is called a finger print. A good operator at Gilnahirk could tell if he was listening to the same German WT operator even though the frequency may have changed.
This is just one example of the important role of the few huts, a collection of telegraph poles and a metal tank in the town land of Ballyhanwood played in the war against Nazi Germany.
The wartime site is gone and the town land of Ballyhanwood has returned to green pastures.
Source: benvista.
Article ID: A8533811
Date: 14-01-2006
THE Y-SERVICE.
The "Y" service was a network of British signals intelligence collection sites, the Y-stations. The service was established during the First World War and used again during the Second World War. The sites were operated by a range of agencies including the Army, Navy and RAF, and the Foreign Office (MI6 and MI5). The General Post Office and the Marconi Company provided some receiving stations, ashore and afloat. There were more than 600 receiving sets in use at Y-stations during the Second World War.
The "Y" name derived from Wireless Interception (WI). The stations tended to be one of two types, for intercepting the signals and for identifying where they were coming from. Sometimes both functions were operated at the same site, with the direction finding (D/F) hut being a few hundred metres from the main interception building to minimise interference. The sites collected radio traffic which was then either analysed locally or, if encrypted, passed for processing initially to the Admiralty Room 40 in London and then during World War II to the Government Code and Cypher School at Bletchley Park in Buckinghamshire.
In the Second World War a large house called "Arkley View" on the outskirts of Barnet (now part of the London Borough of Barnet) acted as a data collection centre, where traffic was collated and passed to Bletchley Park; it also housed a Y station. Much of the traffic intercepted by the Y stations was recorded by hand and sent to Bletchley by motorcycle couriers, and later by teleprinter over Post Office landlines. Many amateur radio operators supported the work of the Y stations, being enrolled as "Voluntary Interceptors".
The term was also used for similar stations attached to the India outpost of the Intelligence Corps, the Wireless Experimental Centre (WEC) outside Delhi.
Specially constructed Y stations undertook high-frequency direction finding (D/F) of wireless transmissions. This became particularly important in the Battle of the Atlantic where locating U-boats was vital. Admiral Dönitz told his commanders that they could not be located if they limited their wireless transmissions to under 30 seconds, but skilled D/F operators were able to locate the origin of their signals in as few as six seconds.
The design of land-based D/F stations preferred by the Allies during the Second World War was the U-Adcock system, where a small operators' hut was surrounded by four 10 ft-high (3.0 m) vertical aerial poles, usually placed at the points of the compass. Aerial feeders ran underground, surfaced in the centre of the hut and were connected to a direction finding goniometer and a wireless receiver, that allowed the bearing of the signal source to be measured. In the UK some operators were located in an underground metal tank. These stations were usually in remote places, often in the middle of farmers' fields. Traces of Second World War D/F stations can be seen as circles in the fields surrounding the village of Goonhavern in Cornwall.
Y station sites in Britain:
Beachy Head, Sussex
Beaumanor Hall, near Loughborough, Leicestershire (operated by the Army)
Beeston Hill, Beeston Regis, Norfolk
Bishop's Waltham, Hampshire (operated by the Army)
Brora, Sutherland
RAF Canterbury, Kent
RAF Cheadle, Cheadle, Staffordshire
RAF Chicksands, Bedfordshire (operated by the RAF)
RAF Clophill, Bedfordshire
Cromer, Norfolk
Forest Moor, near Harrogate (operated by the Army)
G.P.O. Transatlantic Radiophone Station Kemback, near Cupar, Fife
Denmark Hill, Camberwell (operated by the Metropolitan Police and General Post Office (GPO) for the Foreign Office)
Met Office Dunstable, Bedfordshire
Felixstowe, Suffolk
Gilnahirk, Belfast
Gorleston, Norfolk
Hall Place, Kent
Harpenden, Hertfordshire (Army, No. 1 Special Wireless Group)
Hawklaw, Fife
HMS Flowerdown, Winchester, Hampshire
HMS Forest Moor, Harrogate, Yorkshire
Kedleston Hall, Derbyshire
RAF Kingsdown, Hollywood Manor, West Kingsdown, Kent
RAF Monks Risborough, Monks Risborough, Buckinghamshire
Knockholt, Kent (run by the Foreign Office for non-Morse radiotelegraphy signals)
Markyate, Hertfordshire (operated by the Army)
Newbold Revel, RAF 'Y' Service Secret Intelligence and German Telephony Communications Base, Warwickshire.
North Walsham, Norfolk
Sandridge, Hertfordshire (operated by the Foreign Office)
Saxmundham, Suffolk
Scarborough, Yorkshire (operated by the Royal Navy)
Shenley Brook End Milton Keynes (operated by the Army)
South Walsham, Norfolk
Southwold, Suffolk
Stockland Bristol, near Bridgwater, Somerset
Stockton-on-Tees, Cleveland
HMS Ventnor, Rew Down, Isle of Wight
RAF Waddington, Lincolnshire
Whitchurch, Shropshire in The Old Rectory, Claypit Street (operated by the Foreign Office)
Wick (operated by the RAF)
Wincombe, Donhead St Mary, Wiltshire (operated by the GPO for the Foreign Office)
Withernsea, East Yorkshire from a pub, the St. Leonards, now known as Captain Williams
Woodcock Hill, Sandridge, St Albans
Source: Wikipedia.
Listening to the Enemy: Ventnor’s Y Station.
Most people who live in Ventnor know about the WWII radar station on top of St Boniface Down, which anchored the western end of the original
Chain Home early warning system and was the reason for the heavy German bombing raids that damaged many parts of the town.
What fewer people know is that Ventnor was home to part of another, even more secret system that was critical to the Allied victory. It was the
site – the only one on the island -- of one of the twenty or so Royal Navy ‘Y stations’ (from ‘WI’ for Wireless Interception) that intercepted and
located enemy transmissions and passed the information on to Portsmouth HQ and Bletchley Park (‘Station X’) for decoding. If the radar
stations were the ‘eyes’ of the war effort, the Y stations were the ‘ears’.
The headquarters of the Ventnor Y Station was 'The Heights' on Whitwell Road, a large private house (later a hotel, demolished in 1989 and
now the site of the Foxhills estate), with additional accommodation at a nearby house called Chilonga. Manned by Wrens from the WRNS
Special Duties (SD) Service, it mostly intercepted messages in the German Naval Enigma code, which was broken by Bletchley Park. Reading
these messages was critical for winning the Battle of the Atlantic against the U-boats.
Other messages, in a simpler, more easily broken code, were sent by local naval facilities, harbour masters and lighthouses on the French coast
and in the Channel Islands. By knowing which lighthouses were to be turned on and when, the Royal Navy could deduce if German E-boats
were planning a sortie or the movements of coastal convoys. The failure to pick up any such messages on the night before D-Day in 1944 was
an important sign that the invasion had achieved the necessary surprise.
As important as intercepting the messages was, knowing where they came from was equally valuable. Some Y Stations, such as Ventnor, had
DF (Direction Finding) facilities, usually a 30-foot wooden tower on a concrete base, incorporating a hut with a swivelling antenna. If two or more
stations could get a bearing on an enemy transmissions, the sending ship could be precisely located. A skilled operator could pin down the
bearing in as little as six seconds.The Ventnor tower stood on Rew Down, above the Heights. Such towers had to be a few hundred yards from the main receiving station to avoid interference. Most such towers were manned by a single person, and it could be quite scary at night under strict blackout conditions. At Ventnor, the operator had to sit with her back to the door, which could be even more nerve-wracking.
On 15 July 1944 the tower was damaged by a V1 ‘doodlebug’ flying bomb, which also blew out windows of several houses along Whitwell Road. A large crater about 100 feet from the site of the tower is still visible. The Y station wasn’t the target – V1s were accurate only to within a few miles at best. The six buzz bombs that exploded on the Island during the course of the war were all probably aimed at Portsmouth or Southampton! It was sheer bad luck that this one hit where it did, so close to the DF tower.
The tower was repaired, but the Ventnor Y station ceased operation by September 1944, presumably because Allies now controlled the parts of
France and the Channel it monitored. The tower remained standing until 1948 or 1949, but all that now remains is an octagonal brick ‘pillbox’
just below the V54 bridle path, with a concrete foundation and external concrete pads for the wooden supports. Its nature was a mystery until
quite recently: some people did remember the tower, but thought it was a transmitter, part of the radar station, or an observation post. Most
investigators weren’t even aware the tower had been there, and thought the brick structure was likely to have been an anti-aircraft gun
emplacement or the housing for a generator for a searchlight.
A few years ago, members of the Isle of Wight Industrial Archaeology Society began an investigation of the structure, identifying it as a DF
tower. Their findings were instrumental in the Grade II listing of the site by English Heritage in October last year. It is one of the best preserved
Y station towers nationally and possibly only one of two that retain their brick blast wall.
Jeff Mazo, Ventnor & District Local History Society. Main sources: Historic England, “Remains of a Direction Finding (D/F) tower, Ventnor YStation” List entry number 1427450, 26 October 2015; Gwendoline Page, ed., They Listened in Secret (2003).
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