The Diepholz, Germany based Value Added Distributor Secura Systems markets three products to cover the different demands made of terrestrial radio links. Each of these is optimized for the distance it is expected to cover and operates in the relevant unlicensed frequency band for the country of installation. Contemporary and innovative features enable a wide range of applications.

If you've tried installing a satellite dish for a friend recently, one of the first things you will have checked is if there is any object between the satellite and where you want to mount the dish. Reception from geo-stationary orbit is strictly line-of-sight only. Coming down to earth and a little further down the frequency spectrum, but still in the Gigahertz range, a clear line of sight between transmitter and receiver significantly helps signal strength and thereby a robust connection. However, Secura's ‘Wave' range of microwave links does not necessarily need an unobstructed path in order to provide reliable point-to-apoint or point-to-multipoint communication at respectable data rate.

The Wavesprint, the ‘baby' of the family, is built to cover distances of up to 1 km and, depending upon local conditions, will provide up to 54 Mbps of bandwidth. Typical applications for this system are the transmission of data between company buildings that are separated by roads or rivers for example, to deliver CCTV images from distant cameras to a central control room or to provide that difficult last-mile access for broadband data or voice services.

The radio equipment and integrated antenna are both contained in one ruggedized housing that is hardly bigger than a man's hand. All that is needed to set up the link comes in one box and everything is pre-configured for rapid deployment. A built-in SNMP interface also allows easy integration with existing network management and monitoring tools.

In for the Long Haul
Where the application demands a longer range, the Waveflow system provides point-to-multipoint bridging at up to 5 km. It also meets the requirements of bandwidth-hungry CCTV by supplying data rates up to 108 Mbps, depending upon conditions. This is equivalent to the performance of cabled Ethernet and represents a transparent link that bridges a gap that cannot be filled by cabled solutions.
The high-end solution for wireless access applications is called Wavemax. It will typically find application with utility companies and telcos, with local government and emergency services but also in security installations where a range of up to 40km is required. The Wavemax can form part of a WAN or MAN configuration and also help to efficiently extend enterprise networks.

Fit to Burst
This system can make do with near-line-of-sight and, thanks to the OFDM encoding employed, it copes well with potential interference sources. Security and throughput are ensured by a unique packet compression and bursting technology together with many flavors of WEP and WPA protection, MAC address filtering and 802.1x radius client support. The Wavemax is optionally available as a stand-alone unit for use with a separate antenna or integrated into one casing that is weatherproofed to IP67+ standard.

With this comprehensive range of equipment, the list of potential applications becomes very long indeed. Some case studies demonstrate how the installation of these radio links can provide very effective solutions to everyday problems. The London Borough of Hackney, for example, is responsible for an inner-city area that features many high-rise residential buildings. The council has installed a large number of CCTV cameras over recent years to act as a crime deterrent and to provide peace-of-mind for residents. The challenge was to get the video stream from the cameras to the control room with minimal civil engineering work.

The DSSL Group of Basildon specializes in supplying CCTV and access control systems and recommended that the council use Secura Wavemax equipment to transport the video streams. As many as ten cameras can be working on one building and this amounts to a significant total bandwidth requirement. Here the system's software accelerators handling the compressed data deliver up to 21 Mbps of throughput over a range of some 2km. This conforms with the Hackney project requirements and also gives room for the planned future system expansion with the addition of internal access point hotspots linked into the existing Wavemax backbone.

Ring Road
That security at airports is both high and involves a lot of effort is known to every air traveler. The responsible security managers at one airport decided to move the first line of defense against terrorism and other crime by employing automatic number plate recognition cameras on the approach roads. A total of 28 cameras deliver images 24/7 to a central control and processing point over compact Wavemax and Wavesprint systems that are mounted on lamp posts along the perimeter roads at around 4 meters height. This ensures that the radio link is focused along the road, does not cross the airport compound itself and therefore cannot interfere with other essential airport systems that operate on similar frequencies.
These two CCTV applications demonstrate how the Wave series of fixed radio links can be employed to transport data either point-to-point or point-to-multipoint, where cable or fiber solutions would be too expensive or even impossible to realize. Fitted with wide-angle antennas, they can also be employed to transport all types of data between vehicles and fixed points. Train to track, covert observation from vehicles and even VoIP or data transmission from passing ships can all be effectively and reliably implemented by selecting the right system for the specific operating conditions. Effective use of the high bandwidth and long range of these systems can inspire some very innovative value-added applications.