GB2371410A - Platform with collapsible antenna support structure - Google Patents

Abstract

An antenna support system mounted on a platform comprises a pivotally connected antenna support pole and base. The pole is usually upright but may be pivoted into a horizontal position to allow for maintenance of the antenna elements which are located at the end of the pole. The platform is suitable for mounting on a sloping bank and may be supported by ground engaging feet, preferably at the corners of the platform. A counterbalance may be included, which may incorporate springs and/or hydraulic rams. Typically the platform might be located in a road or rail cutting, and may extend longitudinally in a direction parallel to the road or track. The antennae may be suitable for various radio communication systems.

Description

ANTENNA SYSTEM

The invention relates to an antenna system, including support pole and platform structure, in particular for a mobile cellular communications system, for use as an additional antenna in a geographically shadowed area and in particular a narrow, high-walled area with limited additional space for antenna siting such as might be encountered for example in a railway or roadway lying in a cutting or at a tunnel entrance.

State of the art mobile communication systems generally use antenna arrays disposed geographically so as to provide a cellular system of coverage over a geographical area. Such communication systems may fail to produce the desired geographic coverage because of atmospheric conditions, geological factors and various other reasons. In particular, propagation factors, such as natural topography and physical obstructions, may attenuate radio frequency coverage more in certain positions than in others to distort the effective geographic coverage. As a result, antennas frequently yield non circular, non uniform geographic coverage under actual operating conditions.

One of the most problematical areas in which gaps in cellular coverage are encountered arises in relation to deep cuttings and tunnels built to accommodate the road bed of, for example, a railway system or road network.

A conventional cellular network of antennas is likely to fail to penetrate effectively to any great extent into deep cuttings and tunnels which therefore represent a serious gap in coverage.

To date there has been no effective solution to this problem. Providing further antennas to increase the cellular coverage is unlikely to be effective wherever

these are located if they remain outside the cutting or tunnel area. However, siting of an additional antenna, even of a relatively small size, within the shadowed area is frequently entirely impracticable because of the very limited free space for siting which is available in many deep cutting, tunnel and tunnel entrance environments, particularly in a railway system.

In many railway cuttings, flat space in the permanent way bed is at a minimum, and once allowance is made for the necessary working envelope for railway operation relatively little space may be left for siting of any other objects. In many instances, the deeper the cutting, the more space is likely to be at a premium.

In the case of tunnels, placing an antenna in a tunnel is unlikely to be practical from space considerations. However, placing an antenna at or about the tunnel entrance is frequently not an option either. Not only is there rarely much additional space beyond the working envelope of the railway even in tunnel approaches, but also planning issues may arise, where the tunnel entrance has some architectural or other merit, and where the planning authorities are likely to discourage the siting of antennas to the detriment of this. Accordingly, the preferred option for tunnels will be to place an additional antenna away from the tunnel portal but in practice this will still normally need to be within 100 metres of the tunnel portal, which in many instances will necessitate a site within a deep cutting on the tunnel approach with all the siting problems already outlined.

It is an object of the present invention to provide an antenna system which mitigates some or all of the above problems.

It is a particular object of the invention to provide an antenna system which is effective to fill in gaps in the covered areas of a network of conventional cellular antenna systems arising in particular in relation to deep cuttings and tunnels for railway and roadway systems.

It is a particular object of the present invention to provide an antenna arrangement of compact design which can be sited in deep cuttings, such as railway cuttings, compactly against a pre-existing bank where little or no flat space is available without requiring extensive excavation work.

Thus according to the invention, an antenna system with supporting structure comprises an active transceiving portion, a pole having a base portion and a shaft portion, wherein the base portion is adapted for mounting on, and in particular is mounted upon, a platform surface of a reverse or up-bank platform structure, and wherein the base portion and shaft portion are articulately mounted together by means of a generally horizontal pivot such that the shaft portion is pivotable from a normally upright position in which the active transceiving portion is maintained at an elevated location to a more horizontal position for ease of accessibility for repair and maintenance.

Reference herein to a reverse or up-bank platform is to a platform structure, in particular a structure adapted for use in railway cuttings where limited flat ground space is available, which is specifically adapted to abut against a sloping side of such a cutting (being an earth bank, retaining wall or other surface), in that the platform structure comprises a platform member with one edge supported just above the surface of a sloping bank by at least one ground engaging standing support means, the platform member extending generally transversely out therefrom to provide a generally horizontal standing surface, the platform member being provided with at least one ground engaging

standing support means, extending from a lower surface thereof apart from the said first edge (and in particular, towards a distal edge thereof). The reverse platform allows a platform surface to be provided for mounting of the antenna support pole within a cutting even where there is little or no flat space beyond the operational envelope of the railway. By provision of a suitable sized platform surface, and suitable lengths of ground engaging standing support legs, a platform surface of desirable width can be provided which can accommodate the antenna system on a platform which extends transversely out from the bank to provide a flat surface of sufficient extent without impinging on the operational area of the railway or roadway.

The use of a reverse platform enables the antenna to be sited within a deep cutting even when there is no flat space available on the track bed beyond the operational envelope of the railway. The articulating pivot between the antenna pole base and the antenna pole shaft allows for in situ repair and maintenance of the antenna system without the need for the associated structures which would otherwise be necessary for a fixed antenna to enable a technician to reach the active portion and which would therefore again tend to require a greater footprint area in a transverse direction or the use of a temporary structure or ladder with the associated safety implications. Rather than providing such structure or ladder, the antenna is simply pivoted to a near horizontal configuration for repair or maintenance.

The combination of reverse platform and articulated antenna support pole thus produces a compact and practical design for fitment within an existing environment such as a deep cutting with minimal or no need for excavation of the cutting or other work, even where little or no flat ground space is available between the operation envelope and the beginning of the bank. The invention

provides an antenna system which uses existing antenna technology in a compact design effective to fill in gaps in the covered areas of a network of conventional cellular antennas in deep cuttings and at tunnel entrances. The arrangement can be sited against a pre-existing bank even where little or no flat space is available without requiring extensive modification to the cutting itself.

Reference herein to a transverse direction is to a direction generally outwards from a bank of a railway cutting or the like, and hence generally perpendicular to the direction of travel of the railway or the like. Reference herein to a longitudinal direction is to a direction generally parallel to the bank, and hence generally parallel to the direction of the railway or the like. It will be understood by a skilled person that the terms are used to facilitate an understanding of the general orientation of the invention in use, and are not to be interpreted strictly geometrically. In particular, there will be many instances in practice where cuttings or the like do not have entirely parallel walls and/or do not have walls entirely parallel with the roadway or rail trackbed, or where a section of track is not entirely straight, but the invention is nonetheless effective provided the general orientation is followed.

The antenna shaft portion is pivoted from an upright configuration for use (in which the active portion is raised up to an operational height) to a near horizontal configuration for repair or maintenance. It will be apparent from this that for optimum operation the generally horizontal pivot should act to ensure that the base portion and shaft portion of the antenna support pole are articulated to pivot in a plane which lies generally parallel to the bank. If the plane in which the antenna pivoted was significantly different from this, the antenna would tend to impinge either upon the bank or upon the operational window of the railway or road as it approached its horizontal configuration.

Preferably, the platform surface of the reverse platform extends in a longitudinal direction beyond the base area of the antenna to provide an additional working platform area to facilitate access to the active portion when the antenna shaft of the support pole is pivoted to a generally horizontal configuration for repair and maintenance of the active elements thereof. Conveniently, the longitudinal extension of the platform surface may be offset back (i. e. , extends transversely to a lesser extent than the platform surface in the base area) to allow the antenna system to pivot freely to a generally horizontal configuration without the antenna impacting on the platform surface or other equipment.

The longitudinal extension of the platform may also be used as a support platform for other equipment, whether associated with the antenna or not. In a preferred embodiment, the longitudinal extension of the platform may provide a suitable site for one or more cellular communication base transmission stations for association with the antenna system. The platform surface may comprise suitable mounting to accommodate appropriate equipment cabinets, etc. Employing the offset position for the longitudinal extension maximises the space available for other equipment, and/or the space available for an operator to stand on whilst effecting repair and maintenance of the active portion of the antenna system.

Articulation between the base portion and the shaft portion of the antenna support pole is via a generally horizontal pivot. Releasable locking means are preferably provided to lock the system with the shaft in a generally upright position.

The base portion and shaft portion of the support pole are both preferably hollow, for example preferably hollow tubes, to allow wires, cables or the like to provide for electrical communication from the active portion which will usually be at or towards an upper end of the shaft distal from the point of articulation. The base portion, shaft portion and horizontal pivot co-operate together to allow these wires or the like to run down the inside in a manner which is not affected by pivoting of base and shaft from the vertical to the repair position.

For convenience of operation, the articulation between base portion and shaft portion is preferably located towards the bottom of the antenna support pole, for example in close proximity with the platform surface. However, there is then a tendency for the pivoting shaft and active portion to be somewhat top heavy. For safety, counterbalance means are preferably provided in association with the pivot to counterbalance the effective weight of the portion of the antenna above the pivot as the antenna is pivoted from and to an upright position.

Conveniently, these counterbalance means comprise an arrangement of springs and/or hydraulic rams attached or attachable between the shaft portion and the base portion. In particular, the counterbalance means comprises a hydraulic ram, for example where a piston of the ram is connected or connectable to the base portion, and a cylinder of the ram is connected or connectable to the shaft portion at a point closely adjacent to the base portion or vice versa.

The antenna is preferably a directional antenna, and is preferably configured and arranged on the platform to have directionality generally parallel to the direction of the track cutting or the like. Preferably, the antenna is a highly

directional antenna, such as a YAGI dipole antenna which will be familiar to those skilled in the technology. Alternative directional designs can also be used, including flat panel antennas. Thus configured, the directional elements of the antenna will point generally up and down the road, track or the like generally between the cutting walls or other obstructions to provide maximum coverage along a length of a deep cutting and/or through a tunnel portal and into a tunnel or otherwise between obstructions.

Directional antennas are normally required in order to minimise the exposure to radio frequency radiation experienced by passengers who may be travelling in railway carriages or motor vehicles that pass close to the antenna system.

By directing the radiation longitudinally along the cutting the antennas also reduce the amount of radiation transmitted in a transverse direction towards passengers alongside the antennas. If directional antennas are not used, then some form of additional screening may be necessary to reduce radiation exposure to acceptable levels.

For the present envisaged application, the active antenna elements will be preferably 3 metres to 7 metres in height above the railway track bed. This height range is chosen to be sufficient to allow radiation to pass over the top of an adjacent train carriage in order to reach a second train travelling on an adjoining track, but not so high that the radiation might be obstructed by any nearby bridge or could not easily penetrate the aperture of any nearby tunnel portal. Where the invention is applied to roadway cuttings, then different antenna heights may be appropriate, depending on the height of the vehicles using that road and the height of any nearby bridges or tunnel portals.

In all cases, the active antenna elements should be mounted high enough that any personnel having access to the ground area around the antenna is not

exposed to excessive levels of radiation. Maintenance engineers walking onto the platform should preferably be able to walk underneath the active antenna elements without being exposed to excessive levels of radiation. Because safe radiation exposure levels are directly related to frequency, if each active antenna element is operating at a similar power output, those antenna elements operating at the lowest frequency should generally be placed above those operating at a higher frequency.

Any number of active antenna elements may be attached to the support pole within the height range specified provided that adequate vertical spacing is maintained to prevent radio interference between adjacent antenna elements.

Where a number of different radio frequency bands are required at the same site then dual-band or tri-band antenna elements could be used as appropriate.

Where radio coverage improvement is required in both directions, then directional antennas will be mounted in pairs, pointing in opposite directions.

The antenna system as described is generally applicable to all radio communication systems but especially those operating within the UHF frequency bands (from 300 MHz to 3 GHz) due to the availability of suitable directional antennas of reasonable dimensions. In particular, these bands include TETRA systems operating at around 400 MHz and 500 MHz, Cab Secure Radio systems for railways operating at around 450 MHz, DECT systems operating at around 1900 MHz, analogue cellular systems operating at around 450 MHz and 900 MHz, digital cellular systems operating at around 900 MHz, 1800 MHz and 2200 MHz. This latter category of digital cellular radio systems includes those known to radio engineers as GSM, PCN and UMTS (or third-generation) systems and derivatives thereof, such as GSM-R.

If the antenna system is used for radio transmissions operating within the VHF frequency bands (30 MHz to 300 MHz), as used by some emergency services and Private Mobile Radio systems, then highly directional active antenna elements may be too large for mounting on the hinged pole. In this case, it may be necessary to adopt specific means for limiting the exposure to radio frequency radiation experienced by passengers who may be travelling in railway carriages or motor vehicles that pass close to the antenna system.

Such means may include, but are not limited to, additional screening elements attached to the support pole or the use of relatively low power radio base station transmitters. Similar measures may also be needed to avoid other persons being exposed to excessive levels of radio frequency radiation.

Reverse or up-bank platforms are known in the railway industry for use, for example, for the siting of signalling equipment cabinets in cuttings where space is at a premium. A platform surface for use with the invention may be provided by a single such reverse platform, or by a plurality of such platforms having a modular configuration, and attached together to provide a single continuous or at least partially continuous platform surface.

Each platform member of such a platform surface or platform surface module generally incorporates at each comer thereof one ground engaging standing support. For example, this takes the form of a generally vertical supporting leg. The supporting leg may engage the ground by means of a foot, which may be optionally ground penetrating and/or optionally comprise a generally flat plate to spread the load and/or be adapted for fixing into the ground, associating with an in-ground anchor etc. Preferably, the foot is adapted to support the structure stably on the bank surface with minimal requirement for structural alteration to the bank (such as excavation of foundations). Typically, any top soil is removed to provide a stable standing surface for the

foot, but no significant structural engineering work is required to adapt the existing bank to accommodate the platform. To accommodate the slope of the bank, it will be apparent that the standing supports associated with the comers lying closest to the bank will need to be shorter than those associated with comers distant therefrom. Preferably, the ground engaging standing supports, or at least the longer ground engaging standing supports associated with edges or comers of the platform distant from the bank, are adapted to provide a variable height adjustment to the platform surface. For example the ground engaging standing support may incorporate a support member which is adapted to be selectively adjustable in length.

Means to selectively alter the length for such a support member are well known, and will include, for example but not by way of limitation, the provision of mutually slidable such as telescoping parts, or hinged or modular portions. Alternatively, supports may be provided in a variety of fixed lengths.

Means are preferably provided to lock the ground engaging standing support at a desired length in situ.

In a preferred embodiment, the or each platform member is supported by at least one telescoping leg portion extending generally vertically below a lower surface of the platform member and preferably located towards an edge of the platform member transversely distant from the sloping bank. Typically, the platforms are provided with short legs of fixed length in association with edges and comers adjacent the bank, and telescoping legs to accommodate variable height and ensure a stable horizontal platform surface in association with edges or comers distant from the bank.

The edge of the platform member which abuts the bank is adapted such that the ground engaging standing support, for example, generally vertical

supporting legs, raises the platform just above the ground level at that edge. Means may also be provided to fix the edge of the platform against the sloping surface.

The invention will now be described, by way of example only, with reference to Figures 1-3 of the accompanying drawings in which: Figure 1 is a plan view of an antenna system including support pole and platform structure in accordance with the invention shown in use in a railway cutting; Figure 2 is a side elevation of the embodiment of Figure 1; Figure 3 is an elevation looking along the track of the embodiment of Figure 1.

Referring first to Figure 1 an antenna system is shown consisting of a platform structure (1) on which is mounted an antenna pole (2) carrying directional antenna elements directed generally parallel to the direction of the rail track (3). In Figure 1, the antenna pole (2) is shown articulated to a generally horizontal position relative to the antenna pole base (4).

The platform (1) consists of seven conventional up-bank platform modules (5a, 5b). Each platform module (5a, 5b) is around 2 metres square and adjacent platform modules are slidingly engaged, bolted together or otherwise connected to provide a single semi-continuous surface.

The antenna base (4) is mounted on a platform (5a) which is slightly offset from the remaining platforms (5b). Thus, the antenna pole (2) when pivoted to the horizontal for repair and maintenance lies just forward of the remaining platform members (5b) to maximise available space. The remaining platform members (5b) can thus be utilised to their maximum potential for provision of

storage boxes (7) to accommodate, for example, base transmission stations for cellular communications operators, power equipment, or other equipment associated with the railway but not necessarily with the antenna system as such, such as signalling equipment.

Railings (8) are provided for the safety of operating personnel.

Certain features of the embodiment can be seen more clearly on Figures 2 and 3.

In Figure 2, the arrangement of antenna base, antenna pole, and antenna active elements is more clearly illustrated. The antenna base (4) and pole (2) are shown both in an upright configuration, and in a horizontal configuration, being articulated between the two in the direction of the arrow (A).

The antenna pole is around 5 metres in height to carry active antenna elements (lla, llb) comprising pairs of directional YAGI antennas of known design each encased within a radome. In the particular embodiment, the upper

elements (lib) are dual band at 900 and 1800 MHz and the lower elements (lia) are single band at 2. 2 GHz, but it will be understood that other arrangements and combinations of single-, dual-, and tri-band antennas might be appropriate given the particular cellular systems which are to be operated in the area concerned.

Assuming similar power requirements, known safety factors will suggest that the elements operating at lower frequencies should be mounted higher on the pole (i. e. further away from any operator) to minimise levels of exposure to radiation, as is the case in the present example. The active elements will be mounted at suitable polarisation. It is found in practice that antenna

performance, particularly in relation to tunnels, is affected by a number of factors which can vary considerably depending on whether polarisation is horizontal or vertical. The preferred polarisation might vary dependant upon the particular characteristics of the site. To accommodate different preferred polarisations, each element will preferably be provided with a mounting onto the pole which allows for the element to be mounted at vertical, horizontal or 45 degree polarisation as appropriate.

Figures 2 and 3 also illustrate in better detail the platform arrangement relative to the bank (14). The platform members (5a and 5b) making up the platform (1) are clearly shown. Adjacent platform modules are bolted together by means of fastenings (13) to produce the semi-continuous platform surface (1) on which the pole (2) and cabinet boxes (7) can be mounted. Conveniently, the cables connecting the equipment cabinets and antenna system can be contained within cable ducts (18) secured beneath the platform on which the base (4) of the antenna pole (2) and the equipment boxes (7) are bolted. The safety railings (8) may also be seen. An access ladder (19) is also provided.

The whole site would normally be fenced off (17) from general public access.

The platform is supported by short, fixed-length rear support legs (21) towards each rearward comer of each platform module (5a, 5b), and longer telescoping legs (22) towards the front. In each case, feet (23) support the structure stably on the ground, any top soil being first removed so that the feet sit just below the initial ground surface (14), but no significant civil engineering work or foundation work being required.

As can be seen in particular on Figure 3, the reverse platform structure provides a stable horizontal platform surface for mounting of the antenna system which is built stably into the existing bank (14) without requiring

significant further work, without interfering with existing signalling cabling and the like through the existing conduit (26), and without reducing the operational envelope (C) between the antenna pole (2) and the tracks (3). The invention thus offers a simple engineering solution but nonetheless one that is highly effective in solving the problem of providing additional radio coverage in railway cuttings and at tunnel entrances where limited flat ground space is available.

Claims (20)

1. An antenna system with supporting structure comprising an active transceiving portion, a pole having a base portion and a shaft portion, wherein the base portion is mounted on a platform surface of a platform structure, and wherein the base portion and shaft portion are articulately mounted together by means of a generally horizontal pivot such that the shaft portion is pivotable from a normally upright position in which the active transceiving portion is maintained at an elevated location to a more horizontal position for ease of accessibility for repair and maintenance.

2. An antenna system as claimed in claim 1 wherein the platform structure is a reverse or up-bank platform structure and the base portion is mounted upon a platform surface of the reverse or up-bank platform structure.

3. An antenna system as claimed in claim 1 or 2 wherein the platform structure comprises a platform member with one edge supported just above the surface of a sloping bank by at least one ground engaging standing support means, the platform member extending generally transversely out therefrom to provide a generally horizontal standing surface, the platform member being provided with at least one ground engaging standing support means, extending from a lower surface thereof apart from the said first edge (and in particular, towards a distal edge thereof).

4. An antenna system as claimed in any preceding claim wherein the platform surface extends in a longitudinal direction beyond the base area of the antenna to provide an additional working platform area to facilitate access to the active portion when the antenna shaft of the support pole is pivoted to a generally horizontal configuration for repair and maintenance of the active elements thereof.

5. An antenna system as claimed in claim 4 wherein the longitudinal extension of the platform surface is offset back to allow the antenna system to pivot freely to a generally horizontal configuration without the antenna impacting on the platform surface or other equipment.

6. An antenna system as claimed in claim 4 or claim 5 wherein the longitudinal extension of the platform surface is adapted to provide a support site for one or more cellular communication base transmission stations for association with the antenna system.

7. An antenna system as claimed in any preceding claim wherein the platform surface comprises a plurality of platform surface modules having a modular configuration, and attached together to provide a single continuous or at least partially continuous platform surface.

8. An antenna system as claimed in any preceding claim wherein each platform member or platform surface module incorporates at each comer thereof one ground engaging generally vertical supporting leg.

9. An antenna system as claimed in claim 8 wherein the ground engaging standing supports, or at least the longer ground engaging standing supports associated with edges or comers of the platform distant from the bank, are adapted to provide a variable height adjustment to the platform surface.

10. An antenna system as claimed in any preceding claim wherein the generally horizontal pivot by means of which the antenna shaft portion is pivoted from an upright configuration to a near horizontal configuration is oriented to ensure that the base portion and shaft portion of the antenna support pole are articulated to pivot in a plane which lies generally parallel to the bank in use.

11. An antenna system as claimed in any preceding claim wherein releasable locking means are preferably provided to lock the system with the shaft in a generally upright position.

12. An antenna system as claimed in any preceding claim wherein the base portion and shaft portion are hollow tubes, to allow wires, cables or the like to provide for electrical communication from the active portion to the base.

13. An antenna system as claimed in any preceding claim wherein the articulation between base portion and shaft portion is located towards the bottom of the antenna support pole and counterbalance means are provided in association with the pivot to counterbalance the effective weight of the portion of the antenna above the pivot as the antenna is pivoted from and to an upright position.

14. An antenna system as claimed in claim 13 wherein the counterbalance means comprise an arrangement of springs and/or hydraulic rams attached or attachable between the shaft portion and the base portion.

15. An antenna system as claimed in claim 14 wherein the counterbalance means comprise a hydraulic ram, for example where a piston of the ram is connected to the base portion and a cylinder of the ram is connected to the shaft portion at a point closely adjacent to the base portion or vice versa.

16. An antenna system as claimed in any preceding claim wherein the antenna is a directional antenna, and is configured and arranged on the platform in use to have directionality generally parallel to the direction of any of any road, track, cutting or the like in which or alongside which the antenna is to be placed.

17. An antenna system as claimed in any preceding claim wherein the active antenna elements are at 3 metres to 7 metres in height when the support is in an upright position.

18. An antenna system as claimed in any preceding claim wherein the active antenna elements are multi-band with those antenna elements operating at the lower frequencies placed above those operating at a higher frequency.

19. An antenna system as claimed in any preceding claim rated to operate within the UHF frequency bands (from 300 MHz to 3 GHz).

20. An antenna system as claimed in claim 19 operating with one or more digital cellular radio communication systems selected from those

r Amendments to the claims have been filed as follows

known to radio engineers as GSM, PCN and UMTS (or thirdgeneration) systems and derivatives thereof, such as GSM-R.

20. An antenna system as claimed in claim 19 operating with one or more radio communication systems selected from TETRA systems operating at around 400 MHz and 500MHz, Cab Secure Radio systems for railways operating at around 450 MHz, DECT systems operating at around 1900 MHz, analogue cellular systems operating at around 450 MHz and 900 MHz, and digital cellular systems operating at around 900 MHz, 1800 MHz and 2200 MHz.

21. An antenna system as claimed in claim 20 operating with one or more digital cellular radio communication systems selected from those known to radio engineers as GSM, PCN and UMTS (or third generation) systems and derivatives thereof, such as GSM-R.

Amendments to the claims have been filed as follows

CLAIMS 1. An antenna system with supporting structure comprising an active transceiving portion, a pole having a base portion and a shaft portion, wherein the base portion is mounted upon a platform surface of a reverse or up-bank platform structure, and wherein the base portion and shaft portion are articulately mounted together by means of a generally horizontal pivot such that the shaft portion is pivotable from a normally upright position in which the active transceiving portion is maintained at an elevated location to a more horizontal position for ease of accessibility for repair and maintenance.

2. An antenna system as claimed in claim 1 wherein the platform structure comprises a platform member with one edge supported just above the surface of a sloping bank by at least one ground engaging standing support means, the platform member extending generally transversely out therefrom to provide a generally horizontal standing surface, the platform member being provided with at least one ground engaging standing support means, extending from a lower surface thereof apart from the said first edge (and in particular, towards a distal edge thereof).

3. An antenna system as claimed in any preceding claim wherein the platform surface extends in a longitudinal direction beyond the base area of the antenna to provide an additional working platform area to facilitate access to the active portion when the antenna shaft of the support pole is pivoted to a generally horizontal configuration for repair and maintenance of the active elements thereof

Amendments to the claims have been filed as follows

4. An antenna system as claimed in claim 3 wherein the longitudinal extension of the platform surface is offset back to allow the antenna system to pivot freely to a generally horizontal configuration without the antenna impacting on the platform surface or other equipment.

5. An antenna system as claimed in claim 3 or claim 4 wherein the longitudinal extension of the platform surface is adapted to provide a support site for one or more cellular communication base transmission stations for association with the antenna system.

6. An antenna system as claimed in any preceding claim wherein the platform surface comprises a plurality of platform surface modules having a modular configuration, and attached together to provide a single continuous or at least partially continuous platform surface.

7. An antenna system as claimed in any preceding claim wherein each platform member or platform surface module incorporates at each comer thereof one ground engaging generally vertical supporting leg.

8. An antenna system as claimed in claim 7 wherein the ground engaging standing supports, or at least the longer ground engaging standing supports associated with edges or comers of the platform distant from the bank, are adapted to provide a variable height adjustment to the platform surface.

9. An antenna system as claimed in any preceding claim wherein the generally horizontal pivot by means of which the antenna shaft portion is pivoted from an upright configuration to a near horizontal Amendments to the claims have been filed as follows

configuration is oriented to ensure that the base portion and shaft portion of the antenna support pole are articulated to pivot in a plane which lies generally parallel to the bank in use.

10. An antenna system as claimed in any preceding claim wherein releasable locking means are preferably provided to lock the system with the shaft in a generally upright position.

11. An antenna system as claimed in any preceding claim wherein the base portion and shaft portion are hollow tubes, to allow wires, cables or the like to provide for electrical communication from the active portion to the base.

12. An antenna system as claimed in any preceding claim wherein the articulation between base portion and shaft portion is located towards the bottom of the antenna support pole and counterbalance means are provided in association with the pivot to counterbalance the effective weight of the portion of the antenna above the pivot as the antenna is pivoted from and to an upright position.

13. An antenna system as claimed in claim 12 wherein the counterbalance means comprise an arrangement of springs and/or hydraulic rams attached or attachable between the shaft portion and the base portion.

14. An antenna system as claimed in claim 13 wherein the counterbalance means comprise a hydraulic ram, for example where a piston of the ram is connected to the base portion and a cylinder of the ram is connected to the shaft portion at a point closely adjacent to the base portion or vice versa. Amendments to the claims have been filed as follows

15. An antenna system as claimed in any preceding claim wherein the antenna is a directional antenna, and is configured and arranged on the platform in use to have directionality generally parallel to the direction of any of any road, track, cutting or the like in which or alongside which the antenna is to be placed.

16. An antenna system as claimed in any preceding claim wherein the active antenna elements are at 3 metres to 7 metres in height when the support is in an upright position.

17. An antenna system as claimed in any preceding claim wherein the active antenna elements are multi-band with those antenna elements operating at the lower frequencies placed above those operating at a higher frequency.

18. An antenna system as claimed in any preceding claim rated to operate within the UHF frequency bands (from 300 MHz to 3 GHz).

19. An antenna system as claimed in claim 18 operating with one or more radio communication systems selected from TETRA systems operating at around 400 MHz and 500MHz, Cab Secure Radio systems for railways operating at around 450 MHz, DECT systems operating at around 1900 MHz, analogue cellular systems operating at around 450 MHz and 900 MHz, and digital cellular systems operating at around 900 MHz, 1800 MHz and 2200 MHz.