Design For Life: Argosy On Integrated Systems

This may seem like an obvious thing to say, but the key to maintaining a system over its complete life cycle is to get the design right in the first place. So start out with products that are appropriate for the design, says Mike Purnell, Director at Argosy.

At Argosy we supply the down-to-earth infrastructure, and it is just as important to choose carefully here as anywhere else. Are the racks suitable for the project? What about power distribution: do you need dual-feed MDUs for additional security?
In this era of HD moving to 3Gb/s HD and maybe even multiple HD-SDI connectivity for 4K, you need to think carefully about interconnections between equipment. Do you go for copper or fibre?
Traditionally, systems integrators would use co-ax for interconnection between devices and between racks, because it is simple and because any wireman can put a BNC plug on a cable without thinking about it. But when you get to HD and beyond you are right at the technical limits of co-ax cable.
Problems can arise, for example, if a co-ax cable is bent around too small a radius, or if the cable is tightly cinched causing the insulation to deform. This is a real maintenance issue: the systems integrator may have installed the system perfectly, but subsequent work in the rack might disturb the cables and cause problems.
Be clear about this: if you mishandle a co-ax cable carrying digital HD, then it will significantly reduce the transmission level. Digital being what it is, this could mean the signal stops being received and a lot of time is wasted trouble-shooting the devices at either end, when actually the problem lies with a cable tie pulled too tight.
So there is an increasing interest in fibre, even for interconnections between devices. Fibres are now available which are capable of even very tight bends – we demonstrate our BendBright fibre by coiling it around a pencil – so they can stand up to the rigours of life at the sharp end. Fibre patch panels are becoming available in today's market.
But not every device has a fibre I/O port, so you may need to specify external electrical to optical converters, which need their own power supplies. This reduces resilience, as well as increasing the carbon footprint. So the decision may not be clear cut.
The received wisdom used to be that fibre was a nightmare for maintenance engineers as it could not be repaired. That is no longer true: we sell simple kits that allow fibres to be repaired, or new connectors spliced on to fibres. Together with resilient cables for patch cords and interconnects, and bundled fibres for rack-to-rack links, fibre is a good option.
Whether you go for co-ax or fibre, it is really important to choose the right materials. While there are standards for both, they are much more reliable if you match the particular brand and type of cable to the connector.
If you look at our catalogue you may be amazed at the sheer number of different sorts of seemingly identical cables and connectors we stock. Our team will have discussed with the systems integrator which is the right brand and model of cable for the job, and will then have ensured that the brand and model of connector which best matches its physical and signal capabilities will have been supplied to ensure optimum performance.
You need to maintain a stock of the same cables and connectors for future maintenance, so you also need to be sure that they are not nearing the end of their product lives, or that a good equivalent will continue to be available.
Some cables and connectors have a tough life by design. Camera cables – triax and SMPTE fibre – and audio multicore snakes spend their days being dragged around and repeatedly coiled and uncoiled. Good brands designed to take the punishment should have been supplied in the first place, but if you have a problem then we at Argosy offer a rapid test and repair service for OB and studio floor cables to get them back into service as soon as possible.
A problem with a cable or connector stops the signal - and the production or transmission - every bit as completely as a failure of the equipment. That is why it is vital to get the right connections in the first place, and have the same components in stock for instant repairs.
Read the article in the online edition of RFV here.
(IT/JP)