Trends in BUCs (Block UpConverters)

by Jonathan Barter, Director, Product Management 

Probably the most significant advances in today’s BUCs result from improvements in power efficiency, because this one aspect results in tangible benefits in so many areas. Most of the power supplied to a BUC is wasted as heat that needs to be dissipated, so achieving the same RF output power with lower power consumption reduces the size of heat-sinks. This results in smaller BUC housings countering the spiraling cost of raw materials and also reduces tooling and production costs. Reductions in size and weight ripple on to lower costs for packaging, storage and shipping. In operational terms a smaller lighter BUC may also allow use of lightweight antennas, for example the latest 4W BUCs can fit within the weight rating of a Class 1 antenna, extending advances in electronics to the mechanical side of what goes on the roof. 

For low power BUCs the latest designs are only a fraction of the size, weight and power consumption of just a few years ago. As a good example of this new generation, iDirect’s 3W Universal BUC exploits component integration and advanced manufacturing techniques such as direct die-attachment and wire bonding to decrease package weight to 350g and volume to 265cc. (For beer drinkers, that’s about half a pint!) Maximum power consumption is just 22W (P1dB) and when backed off, the Class AB power amplifier design further reduces power demands. 

With opportunities for networks to satisfy the increasingly stringent monitoring and control needs of utilities and oil & gas companies, often requiring remote locations powered by solar or other onsite power sources, reduced power consumption can make all the difference for satellite-based services to succeed – each Watt saved is reckoned to slash $100 off the cost of solar power. In our labs we have measured savings in total power consumption for a site (remote + BUC + LNB + cable losses) of around 50% with the light burst duty cycles associated with SCADA traffic. 

Further up the power curve other benefits result from improved BUC efficiency. Operators sometimes need to deploy BUCs above the 2W – 5W norm. Such BUCs have conventionally been beyond the power capabilities of most IDU, necessitating the use of expensive accessory PSU units from ODU vendors and complicating installation by requiring power injection into the IFL cable or extending power cabling to the outdoors. Improved BUC efficiency can eliminate the need for these power supplies. For example, some of the latest 6W BUCs, such as the NJT5127, are comfortably within the power rating of iDirect enterprise-class remotes and we anticipate this becoming possible with 8W Ku / 10W C BUCs in coming years. 

Another advance in BUC design has been the addition of Extended Ku (13.75GHz upwards) into Standard Ku products, to give BUCs that cover both bands (13.75 – 14.5GHz) at little or no price premium over conventional BUCs. (This also requires an extended span of 750MHz on the L-band IF interface, a feature of both iNFINITI and Evolution remotes.) These ‘universal’ BUCs can eliminate the need to manufacture two product variants, allowing ODU vendors to achieve greater volumes and lower prices. For an operator, particularly those supplying networks into the Middle East and Africa where the use of Extended Ku is becoming more commonplace, ‘universal’ Ku-band BUCs provide the reassurance that terminal systems being deployed today will be able cope with alternative transponders within the Ku-band spectrum and with minimal lead time on volume quantity.