Photo album: "Pointe Suzanne"

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Three weeks have already passed since our arrival to Port-aux-Français. We have shared our time between fitting out the new Géophy laboratory and mounting of cable ducks outside. Those cable ducks permit to put the numerous cables, which connect this laboratory to the rest of the base, beyond the reach of the teeth of the rabbits which infest the island. Today, October 31^st, 1974, we must install a parabolic antenna that will insure the connection to the automatic station that we will set up on Pointe Suzanne hill, at a distance of about 10 kilometres. That station is dedicate to the acquisition of radio signals at very low frequency (VLF) and of very low amplitude. The Pointe Suzanne site has been chosen because it is far enough from the base and from the interferences it generates (particularly the 50 Hz of the electrical mains). It was the essential condition to get good quality signals. All the heavy parts for the construction of that station were disembarked during the Marion Dufresne call on October 4^th and 5^th, before our arrival to Port-aux-Français.

A first segment of the metallic pylon has been fixed on a concrete base and two members of the Geophy team are waiting for the arrival of the second element they will have to bolt down. Bernard Morlet, assistant manager of the Groupe de Recherche Ionosphérique and responsible of the Géophy team, gives his directions.

The second part of the pylon is hanging under the Alouette 2 helicopter which will be used as a crane.

The helicopter, directed by means of radio and gestures, by a mechanic from the "copter" team has brought the element of pylon near the top of the first segment. The two members of the Géophy team hold it while the helicopter puts it upright. As soon as the positioning is right, bolts are inserted in the apposite holes and the two elements are fastened securely.

The helicopter is now fetching the parabolic antenna, in front of the garage door at the other extremity of the Géophy laboratory.

The helicopter is coming back with the antenna hanging on a sling. The members of the Géophy team who are now on top of the second element of the pylon are reaching out to grasp the antenna as soon as it is near enough..

The antenna, still supported by the helicopter, has been positioned and the two members of the Géophy team are bolting it onto the pylon. The orientation of the antenna has been planned to make it point to the direction of Pointe Suzanne where an identical antenna will be set up.

The antenna is now fixed and the sling which linked it to the helicopter has been let loose. A radome protects the front part of the antenna from the elements. Later, the coaxial cable which will join the antenna to the equipments inside the Géophy laboratory is connected.

A few days later, on November 4th, we watch a soviet ship arriving in Golf of Morbihan, she is bringing the different scientific teams who are participating in the ARAKS campaign: GRI and CNES French teams, about 15 Soviet people and six Americans. The ship will live on November 8th. During the campaign we will be about 200 on the base, whilst during the winter party they are about 75 people.  We see, on foreground, a cable duck in construction. At middle ground, we can see one of the many ponds that scatter Grande-Terre.

On November 14th, the helicopter flies us to Pointe Suzanne where we are going to finish the installation of the VLF station, and particularly, proceed with the setting up of two wind generators which will feed energy to the automatic station.

We are drawing near Pointe Suzanne station where we perceive the different shelters, as well as the pylon, already set up, for the parabolic antenna. The VLF station is dedicated to the reception of very low frequency signals, of natural origin, such as wave emission from lightings in thunderstorms, solar or extraterrestrial particles arrival in the upper atmosphere, etc. The study of propagation of this electromagnetic waves, thanks to a network of similar stations, installed in different points of the Earth or on artificial satellites, helps to get a better knowledge of the terrestrial magnetosphere. The antennae (there are two of them) are set up on the ground. They cover the frequency range of 30 Hz - 20 kHz, they are of magnetic type with a great number of cable winding up and a few-meter length.

The helicopter has landed, one of the "copter" team is walking away. As in Dumont d'Urville, these helicopter are Alouette 2 from the French Air Force. There are two of them in Kerguelen during this campaign. The crews, pilots and mechanics, are militaries from the Air Force placed with their machines at TAAF's disposal.

The orange scientific shelter, contains the instrumentation for the acquisition of VLF signals; the multiplex system which allows the encoding of the information to be sent to the Géophy laboratory as well as the decoding of remote control signal arriving from this laboratory; the 2-gigahertz transmitter and receiver that will be connected to the antenna. This shelter permits as well to accommodate four people when the duration of the task they have to do, or when the weather conditions, do not permit them to go back to the base the same day of their arrival. Communication with the base is possible thanks to a telephone line and an interphone passing through the 2 GHz interconnection. There is also a VHF transmitter-receiver, which antenna can be seen above the shelter.

We perceive the two wind generators, still on the ground, and the shelter where the energy supplied by these generators is dealt with. In this shelter, are also the accumulators which permit the station to run when there is no wind.

One of the wind generators is being risen. Tirfor winches are used for this operation. Since the ground is too soft to permit an efficient anchoring, concrete cubes resting on the ground are used to ensure, with their weight, the stability of the anchoring.

In the meantime, the parabolic antenna has been installed too and the 2-GHz interconnection is ready to work as soon as the electrical energy is available.

The two wind generators are now operational. The varying-pitch propellers turn at constant speed as soon as the wind is strong enough. The frequency of the current delivered by the alternators coupled to the propellers is of 9 Hz in order not to disturb the VLF signal acquisition. Each one of the generators delivers a different voltage: 12 V and 36 V, this permits to feed on one hand the electronic equipment and on the other hand all the electric systems without the need of transformers which would not work with a good efficiency at such a low frequency.

In the Géophy laboratory, on November 22nd, I am feasting with my colleagues the end of this operation and the good functioning of the VLF station.

The evening goes on with a dinner which brings together the two GRI teams (Géophy and ARAKS campaign) in the meeting room of the laboratory.

At the end of the dinner (the bottles are empty), happy talking ends the evening.  An outsider to the GRI teams is part of the guests, he is the steward of the base (second from the left), his help has been precious to organise the dinner.

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