History of St Lys Radio – first part

Dear Sparks,

following article by OM Marcin Marciniak – SP5XMI (Technical journalist)

Preface

My articles are written almost entirely from interviews with former sparks – this one is no exception. Thanks to Gerard Clarac F5YD – here is the history of St Lys Radio/FFL as said by Edgar Ambiaud, FFL operator and then Deputy Head of St-Lysradio Center who worked there from 1950 to 1987.

The St. Lys Radio/FFL

The history of St.Lys Radio/FFL goes back to 1941. The station was needed for radio link to French colonies. There were three centers – receiving center in St Lys, a transmitter center in Vernet and an operations center in Muret. All work began in 1942. In 1945 the three centers were almost completed and first link to Bamako was already working. When the war was over, radio center near Paris gradually resumed all its links with overseas. Finally the Group Radioelectric Toulouse was no longer necessary. The station was then used for maritime radio communication. In 1946 Saint-Lys Radio replaced Saintes-Maries-de-Provence la-Mer station that was destroyed during the war and started the work under FFL callsign. Station was open for first traffic in October 1948 with standard CQ tape (CQ de FFL4 FFL4 FFL4 QSX 8 MHZ”) and started its full activity on 1st of January 1949.

(Main building of St Lys Radio receiving center and the antenna field)

The advertisement and the reality

“St-Lys-Radio can communicate with ships around the world on all the oceans of the globe” – the ads said. This was not entirely true. It should have been added “…but not necessarily 24 hours a day, depending on their position”. Up to 8000km from St Lys Radio contact could be established quite easily during the day. Beyond this approximate limit contacts became more and more difficult. Sometimes it was possible for a few hours a day only. During some days it was impossible at all. The R/Os had to choose the frequency range that worked best. For example for a ship in the North-East Pacific the best choice was 8 MHz band at the end of the night, around 4 o’clock UTC (it was called “dark” wave route). FFL could receive quite well. Interference from parasitic emissions produced by nearby powerful and poorly tuned transmitters was quite rare in St. Lys because of the perimeter of protection of the center.

Receiving center was located about 21 km from Toulouse on a clear plateau. Despite its name the station was located 2.5 km away from the village of St. Lys (chief town of canton), in the town of Fontenilles in a place called “Génibrat”. A large central cross-shaped building housed an operating room, offices for management staff and technicians, and various other special premises. It was surrounded by receiving antennas and many metal-wooden masts, almost 30m each.

Electrical substation, local energy distribution devices, self-starting power generators, workshops, garages, shops and warehouses were placed in ancillary buildings, 250 m away. There was also a water tower with well and pumps to supply water to the entire center until the station was connected to the water supply network. Accommodation for staff was built near the village of St Lys in a subdivision called “Cité Radio”. For many years the staff that lived at Cité Radio went to the center by bicycle because there were very few motor vehicles.

Transmitting center was located 20 km from Toulouse, in the lower Ariège valley where ground is flat and clear. Two transmitting buildings, E1 and E2, distant from each other a little more than one km, each had their antennas around. Originally they had directional antennas, that were build for the fixed service, but for the maritime service omnidirectional antennas were also needed. There was a emergency diesel power station and a water tower too. As in St. Lys, the administration had to build housing for the staff. At the time neither the Vernet nor the neighboring communes could provide housing to all the people of the radio center.

(Manintenance works with the transmitting antenna and their feedline)

The antennas

The transmitting center at Vernet used omnidirectional antennas – horizontal two wavelength squares (half wave per leg) called “carrés Gouriaud” tuned for optimal performance on chosen frequency. They were fed by a ladder line and a high frequency transformer.

(Omnidirectional full size square horizontal antenna used at St Lys Radio)

The receiving center near St. Lys used them as well but their main set of receiving antennas comprised broadband rhombics pointing to many different directions. Each “diamond” could cover all six shortwave ranges used at St-Lys-Radio from 4 to 22 MHz. The rhombics were very popular in St. Lys because they made wanted signal stronger and they attenuated unwanted signals from other directions including interferences – all at the same time.

(The diorama of antenna field of the St. Lys Radio).

 

To be continued.

(One of the antenna pilon)

73’s

Marcin Marciniak and webmaster