1. Introduction
The detail of the Flughafenbereich Morlaix—Flugplätze und Ln Anlagen map (Henoff, 2023) in Figure 1 shows the position of some WWII German military installations in the south Finistère studied in past publications: The German radar stations Renntier (QU 300, QU 500) and QU 13 (Tomezzoli, 2021) respectively at the Pointe du Raz and Men Tan and the Y-Peiler station Atlantik II (Tomezzoli, 2024) near Penmarc’h.
In addition, it shows the position of the radio navigation station Elektra/Sonne E6/S6 provided with three antenna masts about 100 m high located respectively on the territories of the municipalities of Lanlean, Ploeven, Plonevez-Porzay, dealt by various authors.
The post-WWII similar, nearby French radio navigation station Consol, it too provided with three antenna masts about 100 m high located respectively on the territories of the municipalities of Guegant, Ploneis, Pluguffan is not shown, but various documents about it exist at the Archives Départementales du Finistère in Quimper.
However, up to now, no author seems to have paid attention to the German base Grille (Figure 1) at Plas ar Horn and Kerdelan Bihan, both near Locronan, 33 km north of Penmarc’h.
Figure 1. U.K.W. Jäger-Sprechstelle Grille position and Unterstellungverhaltnis.
2. Historical Context
Le Bas Breton, the republican newspaper of the district of Chateaulin, on its edition of 28th March 1939 published the article “A quand le phare de Locronan?” (When the Locronan lighthouse will be built?) (Daniélou, 1939) signed by the ancient French minister Charles Danielou (1878-1953) (Gourlay, 1996), in which he summarized the history and the state of his signaling project at La Motte de Locronan, dating back to 1928, and the decision of the Air Ministry of that time to urgently carry out this project, dating back to July 1929. In August 1928, Mr. Etienne Pazkiewicz, a young engineer, was tasked with a first investigation on the terrain. Back in Paris, on 31st August 1928, he informed Mr. Danielou to have pointed out to his director the remarkable location offered by the hill of Locronan, for the installation of a powerful signal and that if a beacon had one day to be established in the region, it was there that it must be located. Few weeks later, Mr. Caquot, director of bases at the Air Ministry, came to the site and not only confirmed the opinion of his subordinate Pazkiewicz, but immediately decided to acquire a surface for the establishment of the beacon and to open a wide access road along the hillside to reach it, while the Air Ministry was still at the beginning of the study the beacon project.
On 10th June 1929, since the project had not yet come to realization, Mr. Danielou sent to the Under-Secretary of State for Air Mr. Laurent-Eynac a letter in which he reminded him that on 26th May 1927, during a lunch, Charles Lindbergh said that the last phase of his Atlantic crossing would have been made easier if, through remote signaling, he had been able to make contact with the European land. Few weeks later, the American pilot Byrd, after reaching the Irish waters, due to a compass accident, nearly got lost in the ocean. Struck by these facts, he reminded to Mr. Laurent-Eynac that it was urgent to establish on one of the Finistère heights, a luminous Hertzian beacon that air navigators were longtime calling for, that the French President of the Council Mr. Raymond Poincaré and the Minister of Finance even suggested and that the Air administration told him that there was no need for new credits. He concluded that, due to administrative delays, after two years, unfortunately, the construction of the beacon was still at the project stage.
To this letter, Mr. Laurent-Eynac, replied on 18th July 1929 informing that the Air administration proceeded on August 1928 to a reconnaissance visit of the Locronan region which permitted to identify the most suitable location for the beacon on the highest point of the hill located two kilometers east of Locronan, that the telephone connection for the beacon would be installed by the post office of the village, that the only difficulty was the power supply of the beacon with electricity, because of the non-electrification of the region. However, studies and preliminary projects of electrification, drawn up by Lebon Company, were subordinate to the formation of a Syndicate of the municipalities of which Locronan would have to be a part, and to the possible results of transactions between this Syndicate and the Company. However, according to very recent Lebon Company information in his possession, a power of 50 kw would be available in the Locronan sector, which would allow to supply the beacon. He concluded by informing Mr. Danielou that the services of the Air administration were alerted so that the construction of the beacon would be pushed forward with all possible diligence.
Two months later, the Syndicate of the municipalities for the electrification of the region was formed under Danielou’s presidency and the electrical network completed six months later.
The Air Minister took advantage of this intercommunal electrical network to have immediately the electrical line for the beacon.
In this situation, Mr. Danielou wrote in the article that after almost ten years since the surface was purchased by the Air Ministry, a wide two km long access road was opened on the hillside, an electrification line established up to the location of the beacon, the beacon still was not existing. Although urgent for transatlantic navigation, the beacon had become urgent also because, in parallel, the nearby aeronautical base of Lanvéoc-Poulmic was activated and, daily, dozens of planes and seaplanes of the base and of the aircraft-carrier Béarn flew over La Motte de Locronan. It was possible that the commander of a French air-wing that crashed on La Motte made a navigation error, but it was certain that the Air Ministers who have succeeded for ten years brought the responsibility of having suspended the implementation of the beacon that president Raymond Poincaré wanted in 1928 and that his minister Laurent-Eynac asked “to push with all possible diligence”.
Daniélou did not have the chance to see his project accomplished because of the rapid German invasion of France. Concerning the Finistère, on 18th June 1940 a motorized vanguard entered Saint-Brieuc. On 19th June, after the departure of the British troops, the burning of the Taulé and the plunder of the Saint-Thégonnec camp by the civilian population, the first German detachments entered Morlaix. The mayor of the city encountered them informing that Morlaix was an open city. Continuing their progression, they crossed Landivisiau and encountered resistance in entering Landerneau were some people died. On 19th June at about 5 pm two motorcyclists arriving from Plabennec at Gouesnou were killed by marine-gunners at the Castel house. In the evening the first German detachment arrived at Brest. At 8 pm they came down from rue Jean-Jaures and rue du Siam and occupied the place of the town.
Some officers at the Prefecture maritime encountered the town authorities and their commander was settling at the Continental hotel. The day after at 3 pm a big parade took place during an hour.
After the signature of the armistice, the Oberst Degener took the direction of the department under orders of the Brittany Gouverneur Generalleutenant Lemelsen. In parallel, the Occupation administration was put in place, each district had its Kommandantur (Le Grand & Thomas, 1980; Le Grand & Thomas, 1981).
The Kommandantur of Locronan was at the Park Trion house at Gorrequer. Some general staffs took turns in Locronan and the 1st Submarine Flotilla of Brest (unit M06 153) in July 1941 requisitioned a hotel and an adjoining building in Locronan for the rest and relaxation of submariners (Floch, 2012).
Who decided the construction of Grille is not known.
Daniélou passed the essentials of the WWII at Neuilly. As the immense majority of the French population, he accepted the collaboration Pétain government, but the departure to London of one of his sons caused the change of his opinion. Aged of sixty years in 1939, he did not actively participate in the French resistance and remained on the side line during the war, although some members of his family were engaged in the resistance and aided British parachutists. His Locronan city council was deposed on 16th November 1944 by the prefect Leconte. Daniélou died in Neully of heart failure on 30th December 1953 (Gourlay, 1996).
Locronan was liberated on 8th August 1944 (Floch, 2012).
3. Grille Position and Organization
The Grille position is indicated on the map by a red dot and a red-character b. The Unterstellungverhaltnis (Subordination relationship) shows on 14th August 1943, the map date, no Grille subordinate relationship. On the map it is identified as: U.K.W. Jäger-Sprechstelle “Grille” Locronan Y8T: U.K.W.—Ultra Kurze Wellen (ultra short waves), Jäger-Sprechstelle (Fighter intercom station), Grille (Cricket), red b (?), Y8T (?). A red cross on the map is superimposed on these indications.
The examination of post-WWII French air reconnaissance images permitted to recognize that Grille was actually formed by two groups of components: a first group at the locality La Motte—Plas ar Horn (Horn Place), in the Forêt du Duc (Duke’s Forest), on the Locronan hill, and a second group at the locality Kerdelan Bihan 1 km east (Figure 2, Figure 3).
Figure 2. Locronan Hill—D—Duke’s Forest; H—Plas ar Horn—Grille first group components; K—Kerdelan Bihan—Grille second group components; L—La Motte; R—road to Locronan (Géoportail). IGNF_PVA_1-0__1948-04-16__C3639-0471_1948_MISSIONBRETAGNE6_0091.
(a) (b) (c)
Figure 3. Grille components—(a) Plas ar Horn—Grille first group components: 1 farm, 2 - 4 shacks, 5 possible bunker, 6 Tromenie trail, 7 Ar Zonj enclosure entrance, 8 Ar Zonj chapel, 9 - 11 possible bunkers, 12 possible Freya radar emplacement, 13 ditch, 14 - 15 possible bunkers; (b) (c) Kerdelan Bihan—Grille second group components: 1 - 8 aerial bases, 9 cabin, 10 shack, 11 - 13 aerial bases (Géoportail). (a) (b) IGNF_PVA_1-0__1948-04-16__C3639-471_1948_MISSIONBRETAGNE6_0091 (c) IGNF_PVA_1-0__1952-05-23__C0319-0051_1952_F0418-0818_0103.
4. The Visit
The Grille sites visit took place on 21st December 2024. Large portions of the terrains at Plas ar Horn and Kerdelan Bihan were covered by mud and vegetation, therefore, only some components and their positions were identified.
4.1. Plas ar Horn—Grille First Group Components
The identified Grille first group components were the following.
A farm (1) (48˚05'56.97"N, 4˚10'47.92"W, height 278.95 m). One of the original buildings on the east side and the original building on the west side disappeared. The two original buildings of different width on the north side and the other of the original buildings on the east side were renewed and adapted to the today’s life.
The emplacement of a rectangular 9 × 8 m shack (2) (48˚05'55.67"N, 4˚10'48.21"W, h. 279.71 m) completely covered by vegetation, consequently its preservation state has not been established.
The emplacement of a rectangular 8 × 5 m shack (3) (48˚05'55.34"N, 4˚10'46.67"W, h. 279.59 m) completely covered by vegetation, consequently its preservation state has not been established. On its west side wall was a square base of a possible tower.
A 5 × 4 m shack (4) (48˚05'54.32"N, 4˚10'47.32"W, h. 279.22 m), apparently built on an original German shack, near a modern telecommunication antenna. The vestiges of the ancient shacks disappeared, and the modern shacks appear in a good preservation state.
The emplacement of a possible bunker (5) (48˚05'56.29"N, 4˚10'50.57"W, h. 279.03 m) disappeared, consequently its preservation state has not been established.
The Tromenie trail (6) (Figure 4) extending towards the north direction for several km, it passed close to the Grille components (5), (12), (14).
A stone pulpit erected in 1887 (7) (48˚05'55.96"N, 4˚10'53.43"W, h. 280.04 m), partially degraded by the weather elements, on the right side and Celtic cross superimposed on a pillar, on the left side at the enclosure entrance of the Ar Zonj chapel (8) (48˚05'56.62"N, 4˚10'53.78"W, h. 279.52 m) (Figure 5). The altar and the religious furniture at the chapel interior witnessed that religious ceremonies were still operated.
The emplacement of a possible bunker (9) (48˚05'56.77"N, 4˚10'55.37"W, h. 278.7 m), completely covered by vegetation, consequently its preservation state has not been established.
The emplacement of a bunker (10) (48˚05'58.88"N, 4˚10'53.51"W, h. 278.83 m) covered by vegetation, consequently its preservation state has not been established.
The possible emplacement of a Flak gun bunker (11) (48˚05'59.33"N, 4˚10'53.39"W, h. 278.24 m) covered by vegetation, consequently its preservation state has not been established.
(a) (b)
Figure 4. Tromenie trail (6)—(a) near the Grille component (12) on the left; (b) near the component (14) on the left.
Figure 5. Ar Zonj chapel enclosure—on the left entrance with the stone pulpit and Celtic cross pillar, in the middle the chapel rebuilt in 1977.
The emplacement of a 4 × 4 m Freya radar bunker (12) (48˚05'55.67"N, 4˚10'48.21"W, h. 279.71 m). Its walls and its protection wall covering its south-east entrance were completely covered by vegetation, consequently their preservation state has not been established.
The emplacement of a triangular ditch (13) (48˚06'00.98"N, 4˚10'57.06"W, h. 272.77 m) covered by vegetation, consequently its preservation state has not been established.
The possible emplacement of a Flak gun bunker (14) (48˚06'04.73"N, 4˚10'52.57"W, h. 257.47 m) covered by vegetation, consequently its preservation state has not been established.
The possible emplacement of a Flak gun bunker (15) (48˚06'09.72"N, 4˚10'57.28"W, h. 272.69 m) covered by vegetation, consequently its preservation state has not been established.
4.2. Kerdelan Bihan—Grille Second Group Components
The identified Grille second group components were the following.
The emplacement of eight aerial masts (1 - 8) covered by vegetation, consequently their preservation state has not been established.
The emplacement of a rectangular 8 × 6 m cabin (9) (48˚05'47.64"N, 4˚09'57.59"W, h. 199.32 m), 1.12 km east from the Ar Zonj chapel, covered by vegetation, consequently its preservation state has not been established.
The emplacement of a 4 × 4 m shack (10) (48˚05'49.45"N, 4˚09'55.42"W, h. 207.47 m) covered by vegetation, consequently its preservation state has not been established.
The emplacement of three other masts (11 - 13) disappeared.
5. Discussion
The meaning of the handwrite red character b near the Grille position on the map is unclear and the meaning of the red cross superimposed on the Grille indications is also unclear. This last probably indicated that at the date of the map: 14th August 1943 Grille was not yet operative or cancelled. The indication Y8T seems to correspond to the Grille numbering order.
The construction dates of the Grille components are unknown. The constructor was probably the Organisation Todt (O.T.).
The position of Grille components at Plas ar Horn on the top of the Locronan hill was dictated by its height of about 280 m dominating the Locronan surroundings.
The farm (1) was probably the Grille headquarter and officers’ lodgment. The courtyard between the east and west buildings was probably the parade ground for military gatherings and ceremonies. The rectangular constructions (2) - (4) were probably personnel lodgments including kitchens, canteens and services.
Grille was connected to Locronan by the 2 km wide access road and power supplied by the electrification line both mentioned by Mr. Daniélou.
The Ar Zonj chapel (8), (Chapelle de la Remembrance), dedicated to Saint Ronan, was built in 1912 and it was probably in use for religious services at Grille. It was rebuilt in 1977 and today’s is one of the major stages of the Troménie Forgivess (Administrateur Breizhnet, 2014).
The star-like structure (Figure 2) included a central cabin encircled by eight aerial masts disposed on a circle of about 15 m in diam. The mast heights and the possible presence of a mast directly leaning to the cabin were not possible to be determined. This star-like structure appears to correspond to a radio direction finder or radio-goniometer similar to a “Hütte II”—FuPeil A 70 h (Staritz, 1985). Actually, it was formed by two quadrupole Adcock antenna stations each formed by four vertical dipole masts rotated by 45˚ from one another. The horizontal conductors from the masts to the central cabin provided the necessary symmetry to cancel the reception of horizontal components of the incident electromagnetic radiation, so that only the incident vertically polarized electromagnetic radiation provided relevant output signals. As a consequence, the station was sensitive only to the vertically polarized components of the electromagnetic radiation coming from a radio source. The eight dipole masts configuration had the advantage of reducing the azimuth error in locating the direction of the radio source. The mast dipoles were all passive and sensitive in a specified range of emitted signals. A display circuitry in the cabin indicated the direction or bearing of the radio source. The radio direction finder was responsive to any located radio source so that it could be used, for example, to respond to voice transmissions from aircraft pilots requesting landing information or to instruct fighter pilots about the targets to be intercepted (Ellis, 1919; Green et al., 1976; Staritz, 1985; Denisowski, 2020).
The radio direction finder was not positioned together with the other Grille components on the top of the Locronan hill but at Kerdelan Bihan at the feet of the hill at about 200 m height. This positioning protected the direction finder against possible air attacks and radio interference signals coming from the northern direction but it obstructed its sensitivity in that direction. Its sensitivity towards east, south and west was unobstructed. This suggests that it was active as control facility for the nearby Quimper airfield (Pluguffan) located south east and that the construction of Grille was probably decided by some authority of the Luftwaffe.
The shack (10) near the cabin (9) was probably a guardhouse.
A jogger and a hunter met by chance at Plas ar Horn, requested for information, resulted unaware of the presence of the Grille components and their history. An inquiry concerning Grille directed to the municipality of Locronan received as reply that no information was available.
The map allows to recognize some other similar WWII German stations: UKW-Jäger-Sprechstelle BIENE at Saint-Renan, UKW-Jäger-Sprechstelle MOTTE at Laniscat, UKW-Jäger-Sprechstelle WESPE—at Keramanac'h (Plounevez-Moëdec), UKW-Jäger-Sprechstelle LIBELLE at Lamballe, UKW-Jäger-Sprechstelle HUMMEL at Plouharnel all depending on the Luftnachrichten-Regiment 54 (Jäfu 4).
6. Conclusion
The visit on the Grille sites permitted to determine that many of its components are covered by vegetation and consequently not recognizable. Therefore, for the moment, their covered and forgotten positions contribute to their preservation, but a more certain legal status and cultural recovery of the sites would be desirable. As usual in such kind of archaeological researches, further issues remain to be investigated: the possible Grille operative state of after the 20th September 1943, its subordinate relationship after that date, its possible missions and services eventually accomplished and the vicissitudes of the personnel in service during WWII. In addition, the map indicates further possible UKW-Jäger-Sprechstelle to be investigated.
Acknowledgements
I express my sincere gratitude to Mr. Henoff for the Mr. Daniélou’s article on Le Bas Breton and the map Flughafenbereich Morlaix—Flugplätze und Ln Anlagen 4318-631.