DE20319983U1 - Lightning protection for antenna systems - Google Patents

Abstract

Lightning protection for antenna systems, with a plurality of vertically offset radiators and radiator arrangements (3), wherein preferably a the radiator or radiator structures (3 ') surrounding, preferably cylindrical protective housing (5) is provided from permeable to electromagnetic radiation material, and having a supporting structure (1), which preferably has a protective housing (5) or a mast-shaped antenna support device preferably comprising the protective housing (5), with the following features:
- a lightning protection device is provided,
- The lightning protection device comprises from top to bottom extending lightning conductors (17), which are preferably mechanically connected to the protective housing (5),
characterized by the following further features:
- The at least one extending from top to bottom lightning discharge (17) is deviated from the vertical so that the lightning discharge or individual portions thereof are aligned in side view at an angle to the vertical direction.

Description

To such antenna systems before Weather and environmental influences to protect, they usually become housed in a surrounding the radiator and radiator structures cylindrical protective housing. It is a for electromagnetic radiation permeable housing, which is usually from a fiberglass reinforced Plastic (GRP) is formed.

Typical dimensions of such cylinders for broadcast transmitters be a diameter of 0.3 m to 4 m and more. The height of such cylindrical protective housing can certainly have values of 20 m to 30 m.

In general, the lightning protection exists from a lightning catcher at the top of the cylindrical protective housing. Frequently to several lightning rods or all common lightning devices circumferentially offset, e.g. in the form of straight running Conduit ends facing radially and vertically upwards Component to the outside protrude and end freely. Possible but are also so-called lightning baskets, where two each diametrically opposite and to the outside extending, in itself free ends of metallic rods over a semicircular electrical connection line or metal rod connected together are, resulting in a basket-like design.

The resulting lightning catcher is then with several offset in the circumferential direction lightning derivatives connected to the outer circumference of the Cylinder in vertical direction down to the cylinder base, where they are connected to the ground potential. By thus formed Lightning conductors, the lightning current from the lightning catcher can be derived to ground become. At the same time, such lightning conductors are also suitable to protect the entire antenna assembly against lateral impacts.

However, all metallic influences Structures inside and outside of the protective cylinder, the electrical properties of the antenna assembly.

For example, the antenna system includes transmitting antennas with horizontally polarized radiators (for example horizontally polarized dipole radiators or slot radiators etc.), so is the Influence of the lightning arrestor in general due to polarization decoupling very low.

In contrast, however, the radiation pattern vertically polarized transmit antennas by a lightning rod strong affected. This basically applies even if alternatively and additionally provided receiving antennas are.

Therefore, it has already been proposed been on such a lightning arrester described above to dispense in the radiation field of the antenna. This then requires however, that possibly over the lightning catcher captured lightning current within the antenna structure is derived in the cylinder, for example, by lightning conductor lines through a hole in the protective cylinder in the interior of the antenna assembly ushered be connected to there with electrically conductive support systems to become. About that can during lightning strike the current down to ground potential guided become.

Object of the present invention is it in contrast, an improved and yet simple lightning protection for antenna systems to create, usually by one for electromagnetic radiation permeable housing are surrounded.

The object is according to the invention solved the features specified in claim 1. Advantageous embodiments The invention are specified in the subclaims.

A clear improvement in the radiation characteristics especially for vertically polarized antennas and transmitting antennas can be realize that the lightning conductors or the lightning arrester structure is designed so that the lightning conductor lines preferably along a spiral from top to bottom and the antenna surrounded with the radiators and radiator structures therein. Preferably, at least two offset by 180 ° to each other Helix provided, which are preferably mounted on the GRP cylinder. Due to the deviating from the vertical direction alignment of the lightning conductor tracks or lightning conductors can cause deterioration of the electrical Property of the transmitting antenna are avoided, if this particular Include spotlights and radiator structures with vertical polarization. The lightning arrester devices simultaneously serve as lightning arresting devices.

A lightning arrester structure formed in this way but can also be used with spotlights or spotlights used, for example, in horizontal polarization send or receive. In other words, such a lightning rod structure Advantages even if the transmitter initially only emitters or radiator structures with should include horizontal polarization. Because even with a belated upgrade the antenna system with vertical radiators or radiator structures this has the advantage that the lightning arrester structure left unchanged can be, since when using the lightning arrester structure according to the invention possibly retrofitted vertically polarized antenna elements with respect to their electrical characteristic Transmission and reception properties are not adversely affected.

The slope of the helical or helical spaced apart from the antenna around this lightning rod structures can vary widely with respect to the slope and / or the number of helices. Preferably, the training is such that at least each vertical strip on the front usually seen cylindrical protective enclosure of the antenna mast system is crossed at least once by the helix, helically or diagonally extending lightning rod structure or lightning conductor line. In other words, the pitch of the helical structure can vary within wide ranges and, for example, preferably more than 20 ° and less than 87 °. Preferred are angular ranges between 40 ° to 70 °. In this case, the pitch of the helix is to be seen in relation to the number of circumferentially offset helical arrangement, since with increasingly denser lightning rod structure ultimately increasing shielding of the radiator and radiator elements could be caused on the antenna mast (Faraday effect). Ultimately, an optimum is to be chosen, which takes into account that the lightning discharge should on the one hand as short as possible from top to bottom to the ground potential (ie as vertical), and on the other hand, the ground dissipation should be sufficiently inclined relative to the vertical in order to obtain the best possible radiation pattern ,

For the sake of completeness, it is also noted that the opposite the vertical sloping lightning conductor discharges, the not only with a vertical component but also with a superimposed one Horizontal component are aligned, not in the sense of a continuous Spiral or helix extending from top to bottom have to. Rather, it is possible that the lightning conductor lines, for example, in side view the antenna mast or in side view on the antenna mast and the emitters surrounding preferably cylindrical protective sheath, for example zigzagged are arranged running from top to bottom. Decisive in the Purpose of the invention is merely that individual, the lightning rod structure belonging electrical leads and leads not aligned exactly vertically are, but when viewing the page are aligned so that their positioning as an overlay a vertical and horizontal component.

The invention will be described below of exemplary embodiments explained in more detail. there show in detail:

1 : A schematic side view of an antenna system with an antenna mast and a cylindrical GRP protective housing with top arranged lightning catcher and two helical lightning conductors;

2 : A perspective view of the lightning conductor structures in three-dimensional rendering with two helical lightning conductors;

3 : a settlement of in 1 and 2 reproduced cylindrical protective jacket only in a partial height with the lightning derivatives thereon according to the embodiment according to 2 ;

4 : one too 3 modified embodiment in unwound side view in the case of three mutually offset helical lightning derivatives;

5 : one too 4 modified embodiment in unwound side view, in which four derivatives are used with a larger pitch angle;

6 a modified embodiment with zigzag from top to bottom extending lightning conductors, where each adjacent lightning conductors are arranged symmetrically to each other; and

7 : one too 6 modified embodiment in side view at unwound protective sheath with lightning discharges extending thereon, the lightning conductors are also provided zigzag, but are the same aligned (ie are aligned the same height).

In 1 is shown in a schematic side view of an antenna system with a lightning protection device.

The antenna system comprises a vertically oriented supporting structure 1 in which, in the vertical direction one above the other and offset in the circumferential direction, a plurality of radiators 3 and radiator structures 3 arranged to send and / or receive. Such an antenna system can serve, for example, as a television and / or radio antenna system which operates, for example, in the so-called Band III (174 MHz to 230 MHz) and / or, for example, in Band IV and V (470 MHz to 860 MHz). Additionally or alternatively, the transmitter can send and receive in the FM range, so for example in the 88 to 108 MHz range.

The whole supporting structure 1 with the radiators and radiator structures 3 is in the embodiment shown in a cylindrical protective housing 5 arranged and thereby protected from environmental influences. It is a protective housing permeable to electromagnetic radiation, usually a GRP housing. The supporting structure 1 can essentially by the cylindrical protective housing 5 be formed, which includes transverse members in the interior at a vertical distance. The radiator and radiator structures can then be fastened inwardly protruding to the protective covering. Alternatively or additionally, but also inside the protective cover 5 Mast-shaped belonging to the support structure facilities may be provided, for example, steel beams, where then the radiator and radiator structures as well as the protective enclosure attached in addition to or connected thereto.

In the upper front end 5 ' of the protective housing is a so-called lightning catcher 9 intended. This includes a conductive, on the front end 5 ' of the protective housing 5 attached end cap 11 on which offset in the circumferential direction with vertical and horizontal component to au radially projecting lightning rods 11a are arranged, which via one or more annular connecting lines connecting them 11b electrically connected, which also provides mechanical support of the lightning rods 11a is guaranteed. Two diagonally opposite ends of the aforementioned lightning rods are preferred 11a by means of convex upwardly projecting the semicircular line sections 11c connected, resulting in a structure formed in the manner of an inverted basket, which is why this arrangement is also called lightning catcher.

According to embodiment according to 1 and 2 are on the outer circumference of the protective housing 5 the lightning catcher 9 with a ground potential 15 at the antenna base 1' connecting lightning conductors 17 intended. These lightning leads 17 exist in the embodiment according to 1 made of two helical or helical lightning conductors offset by 180 ° from each other 17 , which in the embodiment shown after 1 the cylindrical protective housing 5 For example, rotate at least once from top to bottom.

In 2 is a perspective view of this lightning rod structure without antenna mast and spotlights or radiator structures and without lightning catcher 9 played.

In 3 is the side view of the cylindrical protective housing 5 reproduced in developed form.

It can be seen that the individual lightning conductors a pitch angle α with respect to Include horizontal. The gradients of the individual lightning derivatives can be quite in the Magnitude of a few meters. The pitch angle α can therefore preferably values between 20 ° to 87 ° opposite the Have horizontal, in particular values between preferably 40 ° to 70 °.

In principle, a einlündlige lightning rod structure can be selected. In this case, based on the total height of the protective housing, the arrangement should be such that the at least one helical formation of the derivative 17 over the entire length of the protective housing 5 rotates the antenna mast with the radiator and radiator structures at least once, preferably several times.

Based on 4 is merely shown that, for example, three offset by 120 ° to each other, generally helically arranged lightning conductors 17 can be provided. The number can basically be arbitrary, it being only necessary to ensure that, with an increasingly higher number of lightning conductors, as a rule the pitch angle relative to the horizontal should be greater, in order not to make a too dense overall coverage of the outer circumference of the protective housing 5 To obtain with lightning derivatives, so that then at increasingly greater occupancy density shielding of the antenna radiator caused by the so-called Faraday effect. Therefore, in 5 a lightning rod structure with four circumferentially offset lightning conductors 17 shown, the pitch angle α, for example, is steeper than in the embodiment according to 3 and 4 and about 45 °.

Whether the coil or the coils 17 can be left or right around running, can be chosen arbitrarily.

Based on 6 is shown with respect to the reproduced in a page view in the manner of a settlement protection housing that the lightning conductors 17 basically not over the entire height helical or helical or the like must be designed to extend, but only partially so should be designed. Therefore, a more zigzag-shaped derivative structure may result in side view. For the purposes of the invention, it is especially important that over longer distances exactly vertically extending line sections for lightning dissipation are avoided, as this the transmission and reception properties of vertically polarized radiators and radiator elements are degraded.

It is also possible that the lightning discharge, for example, clockwise, preferably on the protective housing 5 is arranged circumferentially and then merges at a certain height in an opposing helix or helical structure. If such a change more often, so it can be spoken of a zigzag structure, as for example with reference to 6 and 7 is explained.

According to the embodiment 6 is the first lightning derivative 17a shaped like a zigzag from top to bottom. The same applies to the lightning discharge 17b . 17c and 17d ,

In the embodiment according to 6 four leading from top to bottom leads 17a to 17d shown, which are aligned in pairs in opposite directions, where they are at their mutually facing coupling points 107 touch. The embodiment is thus chosen as if a clockwise and a left-handed helix (here with the same pitch) are provided, each at the coupling points 107 touch.

Basically, this results also a lightning discharge, which runs zigzagging from top to bottom could be. It could the zigzag Derivatives at their coupling points also separated and laterally be arranged apart.

This is in principle based on 7 explained, in which, however, deviating from 6 the arrangements are aligned in the same direction. In particular, then offers, as this is based on 7 shown is that the individual structures 17a to 17d do not overlap, leaving in an imaginary vertical strip 105 in each case a section comes to lie, in which no lightning discharge structures are provided.

Deviating from the illustration according to 7 However, the lightning rods could also be formed from top to bottom sinusoidal running. Mixed forms between a sinusoidal and a zigzag structure are also conceivable. The lightning conductors have a double function. On the one hand, they serve as lightning conductors and on the other hand they are intended to provide protection against lateral impacts. They are therefore often referred to in the literature as a guide.

In practice, according to one embodiment 7 or, for example, with sinusoidal or rather sinusoidal lightning derivatives, as a rule preferably not only two but three or four such derivatives are provided. By appropriate design, the scope increases. The smallest distance between two adjacent trap lines should preferably be less than 4 m.

Claims (11)

Lightning protection for antenna systems, with several vertically offset radiators and radiator arrangements ( 3 ), wherein preferably one of the radiators or radiator structures ( 3 ' ) surrounding, preferably cylindrical protective housing ( 5 ) is made of material permeable to electromagnetic radiation, and having a supporting structure ( 1 ), preferably a protective housing ( 5 ) or preferably the protective housing ( 5 ) comprises a comprehensive mast-shaped antenna support device, with the following features: - a lightning protection device is provided, - the lightning protection device comprises top-to-bottom lightning conductors ( 17 ), preferably with the protective housing ( 5 ) are mechanically connected, characterized by the following further features: the at least one top-to-bottom lightning discharge ( 17 ) is oriented away from the vertical such that the lightning discharge or individual portions thereof are aligned at an angle with respect to the vertical direction. Lightning protection according to claim 1, characterized in that at least one helix, helical or helical lightning discharge ( 17 ) is provided. Lightning protection according to claim 1 or 2, characterized in that at least two offset by 180 ° to each other lying helix, helical or helical lightning conductors ( 17 ) are provided. Lightning protection according to claim 1 or 2, characterized in that the lightning conductors ( 17 ) are formed spirally in axial plan view and thereby extend over an axial height. Lightning protection according to one of claims 1 to 4, characterized in that at least one lightning conductor ( 17 ) is provided, which merges in side view from top to bottom extending from a right-handed to a left-handed helix, helical or screw structure or vice versa. Lightning protection according to claim 5, characterized in that at least one lightning conductor ( 17 ) is provided, which is formed in side view from top to bottom zigzag or sinusoidal or a mixed form thereof from top to bottom back and forth. Lightning protection according to one of Claims 1 to 6, characterized that the at least one lightning discharge or sections thereof in a pitch angle α arranged who are taller than 20 ° and is less than 87 °, preferably greater than 40 ° and less than 70 °. Lightning protection according to one of claims 1 to 7, characterized in that it is provided in antenna systems, the horizontally polarized radiator and radiator structures ( 3 ). Lightning protection according to one of claims 1 to 8, characterized in that it is provided in antenna systems, the horizontally polarized radiator arrangement, vertically polarized radiator arrangements and / or circularly polarized radiator arrangements ( 3 ). Lightning protection according to one of claims 1 to 9, characterized in that the zigzag and / or sinusoidal or in any other way from top to bottom back and forth lightning discharge ( 17 ) in the direction of the antenna arrangement at least twice, preferably three or four times offset from one another. Lightning protection according to one of Claims 1 to 10, characterized that the antenna system comprises radiators and radiator structures, especially for the DVB-T operation are provided.