EP0237392B1 - Transmission centre, particularly for decametric waves - Google Patents

Description

The present invention relates to a transmission center provided, for example, to operate in HF and comprising transmitters associated with antennas distributed in a given space constituting what is generally called an antenna field.

Such centers are known, they include fixed antennas, transmitters grouped in a central building and a complicated interconnection between the transmitters and the antennas with means for switching, impedance transformation, radiofrequency energy transport distributed over the land with the disadvantages of construction, protection and operation that this entails. In addition, such a center is practically frozen from its conception because modifications and extensions are often very difficult.

The object of the present invention is to avoid or, at the very least, to reduce the drawbacks mentioned above.

This is achieved, in particular, through the use of rotary antennas and through the systematic juxtaposition of antenna-transmitter.

According to the invention a transmission center, in particular in HF, comprising a central building with its central unit designed to manage the operation of the entire center and n (n integer greater than 1) antennas distributed over a field for form an antenna field, is characterized in that the antennas are rotary antennas and in that the center comprises n transmitters associated respectively with the n antennas according to an invariable one-to-one relationship, and n premises arranged respectively at the foot of the n antennas, serve as a shelter for the transmitter associated with the antenna at the foot of which they are arranged.

• la figure 1, un centre d'émission en ondes décamétriques selon l'art connu,
• la figure 2, un centre d'émission comparable à celui de la figure 1 mais selon l'invention.

The present invention will be better understood and other characteristics will appear with the aid of the description below and of the figures relating thereto which represent:

• FIG. 1, a HF emission center according to the known art,
• Figure 2, a transmission center comparable to that of Figure 1 but according to the invention.

By way of convention and to facilitate understanding of the diagrams, the lines bringing the energy necessary for the radiation of the antennas have been drawn in strong solid lines in FIGS. 1 and 2 while the edges of the buildings have been drawn in strong broken lines. Furthermore, to simplify the drawings, with a few exceptions, power lines other than radiofrequency have not been shown.

FIG. 1 represents an HF emission center according to known art. This center includes, in particular, a central building B ′, fixed antennas Af1, Af2 ... formed of radiating doublets and distributed over the field, and an energy supply building, Bj, also called "energy substation ". It should be noted that for the convenience and clarity of the drawing, only two antennas and two transmitters have been shown in FIGS. 1 and 2, in fact the emission centers which have served as an example in the present description would include , for figure 1, four transmitters and twenty antennas and, for figure 2, four transmitters and four antennas. .

The low frequency energy of the substation is supplied to an energy distribution circuit, J, located in the central building, B ′, and is distributed, still in the central building, between the transmitters E1, E2 to give the radiofrequency energy to be emitted and between two circuits Jc and Jb intended respectively to supply the energy necessary for the switching of the radiating elements inside each antenna and the energy necessary for the night lighting of the pylons serving as supports for the antennas fixed.

The central building includes, in addition to the transmitters and circuits used to distribute the energy, a central unit, Uc, consoles, Cs, Ce1, Ce2, Cm, Ca, two control cabinets Cdm and Cda and two distribution matrices Ma and Mr.

The central unit, Uc, includes a computer; it is intended to manage the operation of the entire transmission center.

• pour la console audio, Cs, vers quels émetteurs doivent être aiguillés, par la matrice de répartition Ma, les différents signaux audiofréquence, Sa, à émettre,
• pour les consoles émetteur, Ce1, Ce2, les conditions de fonctionnement des émetteurs E1 et E2, en particulier en ce qui concerne la puissance et la fréquence d'émission,
• pour la console matrice, Cm, à quelle antenne est connecté tel ou tel des émetteurs, la console Cm fournissant pour cela des signaux de commande à l'armoire de commande de matrice Cdm de manière à assurer les liaisons voulues dans la matrice Mr,
• pour la console antennes, Ca, quels sont les signaux à envoyer à l'armoire de commande de commutation d'antennes Cda pour effectuer la télécommande de commutation d'axe de tir dans chacune des antennes. En retour la console Ca reçoit la télésignalisation en provenance de l'antenne avec, en particulier, les signaux de retour des chaînes de sécurité dont le trajet aller est constitué par des lignes qui suivent des trajets parallèles aux trajets de l'énergie radiofréquence entre les émetteurs et les antennes auxquelles ces émetteurs sont connectés ; ces trajets parallèles incluant des contacteurs mécaniquement couplés aux contacteurs traversés par l'énergie radiofréquence, permettent de vérifier si les liaisons désirées ont bien été établies.

The consoles each have a control console and are used to define:

• for the audio console, Cs, to which transmitters must be routed, by the distribution matrix Ma, the different audio frequency signals, Sa, to be transmitted,
• for the transmitter consoles, Ce1, Ce2, the operating conditions of the transmitters E1 and E2, in particular with regard to the power and frequency of transmission,
• for the matrix console, Cm, to which antenna is connected one or other of the transmitters, the console Cm supplying for this purpose control signals to the matrix control cabinet Cdm so as to ensure the desired links in the matrix Mr,
• for the antenna console, Ca, what signals are to be sent to the antenna switching control cabinet Cda to carry out the firing axis switching remote control in each of the antennas. In return, the console Ca receives the remote signaling coming from the antenna with, in particular, the return signals from the security chains whose outward path consists of lines which follow paths parallel to the paths of the radiofrequency energy between the transmitters and the antennas to which these transmitters are connected; these parallel paths including contactors mechanically coupled to the contactors traversed by the radiofrequency energy, make it possible to check whether the desired connections have indeed been established.

The radiofrequency supply lines, in strong lines, which connect the central building B ′ to the antennas Af1, Af2 pass through sets T1, T2 comprising in series a balun and an impedance transformer; the balun allows the passage from a coaxial line transmission on the matrix side Mr to a symmetrical line transmission on the antenna side, and the impedance transformer ensures the impedance adaptation, with a standing wave ratio as close to 1 as possible on the transmitter side.

The fixed antennas Af1, Af2 are associated with switching boxes which, under the control of the Cda cabinet itself controlled by the antenna console, Ca, make it possible to modify the firing axis of the antennas, by switching lines phase shift.

It should be noted that the central building b4, by the amount of resources it houses, is large (more than 60 meters long in the example described) and therefore poses production problems both with regard to its actual construction and its air conditioning. As will appear in what follows, the transmission center according to FIG. 2 does not pose this kind of problem because the central building is much smaller in size there, and the annex buildings associated with each antenna are all identical, of small size, have the same elements and therefore lend themselves to being produced in the form of a factory-made shelter transported by truck, with all the elements it must contain, to the places of operation.

FIG. 2 represents an HF emission center according to the invention. This center comprises, in particular, a central building, B, rotary antennas, A1, A2, associated with premises, b1, b2, to form emission units, Ue1, Ue2, and an energy supply building , Bj, also called "energy substation".

The low frequency energy from the substation is directly conveyed by supply lines to the premises b1, b2. It should be noted that the transport of this energy, because it is low frequency energy, is much easier and causes very much less loss than that of radio frequency energy between the central building and the antennas of the center according to Figure 1; in fact this transport can be carried out by flexible cables laid on the ground or buried whereas, in the case of figure 1, the transport of the radiofrequency energy was done by symmetrical lines, suspended at a height of several meters au- above the ground thanks to posts and insulators.

The central building B in FIG. 2, compared with the building B ′ in FIG. 1, contains only one central unit, U, consoles, Cs, C1, C2 and a distribution matrix Ma.

The central unit, U, has a computer; it is intended to manage the operation of the entire transmission center. It is a simplified version of the central unit according to FIG. 1 since, as will appear in what follows, it does not have to manage the operation of a switching matrix between the transmitters and the antennas; in fact the matrix Mr according to FIG. 1 has completely disappeared in the emission center according to FIG. 2.

The console Cs is identical to the console Cs in FIG. 1, it is an audio console intended to define to which transmitters must be routed, by the matrix Ma the different audio frequency signals to be transmitted.

The consoles C1 and C2 relate respectively to the emission units Ue1 and Ue2; they include the elements of the Ce1, Ce2 consoles in FIG. 1 and the means for developing control signals for the light signaling of the antenna and control signals for the angular position of the antenna; these means are produced in the same way, but simpler (sending a number of bits corresponding to the angle of rotation to be obtained), than the part of the antenna console Ca in FIG. 1 relating to the preparation of signals for the firing angle switching command.

The rotary antennas A1 and A2 are shown in schematic view from above in FIG. 2. At their feet are the premises b1 and b2 which have been discussed further in this description. These premises are, in the example described, made from prefabricated panels and mounted on a concrete slab poured at the foot of each antenna at the same time as the base of the antenna.

The premises b1, b2 each contain an emitter, E1, E2, identical to the emitters of FIG. 1, with, at the output, a balun and an impedance transformer which are therefore grouped in the same room as the emitter and no longer scattered on the ground as in the case of Figure 1; the transmitters receive the audiofrequency signals from the matrix Ma and supply on the one hand the radiofrequency energy to the antenna and on the other hand receive consoles C1, C2 the remote control information and in return supply the remote signaling information which is sent to the consoles C1, C2. An antenna rotation control cabinet, located in the base of the antenna, is controlled by the remote control information received by the transmitter. In the example described, the antennas A1 and A2 are antennas with two vertical curtains of dipoles allowing the two of them to operate from 6 to 26 MHz. It should be noted that it is planned to produce a transmission center according to FIG. 2 but in which the antennas will include means for feeding only part of the dipoles in order to modify the radiation pattern of the antenna; in this other center It is also planned to place the energy substation in the central building.

Claims (2)

1. A transmission center, in particular for decametric waves, comprising a central building (B) which houses a central unit (U) conceived for managing the operation of the entire center, and n antennas (A1, A2) (n being an integer above 1), the antennas being distributed over a site for constituting an antenna network, characterized in that the antennas (A1, A2) are rotating antennas and that the center comprises n transmitters (E1, E2) respectively associated to the n antennas according to a bi-univoque invariable relation, and n premises (b1, b2) respectively disposed underneath the n antennas in order to house a transmitter (E1, E2) associated to the antenna underneath which it is disposed.
2. A transmission center according to claim 1, characterized in that the premises (b1, b2) and their contents are all identical.

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