Navtech offers a wide range of systems to meet all requirements for receiving digital COFDM video transmissions from offshore marine video links. This covers portable equipment, mobile command vehicle systems and fixed site, long range installations. Equipment can be tailored and customised to suit a particular user’s individual requirements.
Medium and Long Range
For reception of video images from ranges up to 100Km (airborne) 50Km (ship to shore), a fixed array of six sector antennas is used. Typically these have a gain of between 15 and 17 dB (depending on frequency band used). The antennas can be roof-top or mast mounted together with their individual frequency ‘block down converters’ (BDC’s). These Sector Arrays do not require GPS tracking.
These BDCs convert the high frequency transmitted signals to lower frequency UHF signals that are then supplied, via simple co-axial cables, to the receiver. The receiver can thus be mounted in an equipment room several hundred meters from the antennas. Standard 19” rack-mount units or ruggedised portable systems are available.
The receiver utilises the latest Maximal Ratio Diversity combining technology for optimal COFDM performance whilst maintaining full DVB-T compliance.
6W MRC diversity COFDM receiver
17dBi sector antenna in diversity array
6W MRC diversity COFDM receiver
3U 19” or desk-top mount
Integral display screen & Keypad for control and monitoring
Remote Control option
Integrated down converters
UHF IF for low loss down feeds
Suitable for permanent outdoor installation
Short and Medium Range
For local reception of COFDM linked video images, the same high performance diversity reception technology that is utilised in the long range system is packaged into a simplified, small lightweight unit. Instead of six high gain sector antennas, two lower gain omni-directional antennas are used (although a high gain antenna can be attached for increased reception range). When operating in high multi-path environments (such as urban areas), particularly when the transmission source or receiver is mobile, the capabilities of diversity reception enable maximum performance and solid, reliable video reception. This 2-way diversity receiver is offered in a variety of packages to suit different applications.
Examples of typical configurations:
‘Grab and Go’ series portable receivers
Battery, DC and Mains operation
Integrated 10.4” High brightness LCD monitor
Mag Mount antennas
‘Mobile Command Post’ receiver
2U 19” rack mounting
Internal or external down-converters
Multiple buffered video outputs and ASI
Mains or 12 - 36 V DC operation
Portable antennas
Diversity Omni antennas with flat panel directional
