Leonardo Busi is president of Elenos SRL, Broadcast Electronics, Elenos, Itelco Broadcast and ProTelevision Technologies, all members of the Elenos Group.
What are the important recent developments in how transmitters are made?
Leonardo Busi: The newest designs in FM and FM digital are based on software-defined modulators, which are field-programmable and updateable for virtually any analog or digital standard worldwide. This means improvements can be made in the field and hardware doesn’t have to change.
If designed properly, the same modulator can also be used for TV operation, which means the manufacturer gets economies of scale, allowing a more competitively priced product for the customer. As the modulator can also be used for the operation in every TV standard as well as almost every radio standard like DAB, HD Radio, DRM and CDR it means the manufacturer acquires more experience that he can turn around to make the product even more reliable and constantly improving.
What do buyers need to know about hybrid radio when buying a transmitter?
Busi: As more and more listener devices offer the possibility to display both dynamic text and graphics drawn from both over-the-air RDS and digital data, as well as the web, it is important for transmitters to be transparent to the data path, and upgradeable as standards change. Bonus points for simple configuration with station playout systems. Coming back to the software-defined modulator, a transmitter must be adaptable for whatever comes next, whether it is DTS AutoStage or HD Radio. It must be adaptable and almost limitless in terms of its flexibility.
How can managers best calculate what a transmitter will cost to operate?
Busi: Total cost of ownership involves far more than AC to RF efficiency – the cost of sourcing parts, the cost of engineering time spent repairing, and the ability to update the transmitter via firmware rather than change hardware all contribute.
A manager should look at not what the cost is in the first year, but what it will be in five years, how easy is it to get parts, how trustworthy is a company to provide those parts. How good of an engineer is required to repair systems, and is the transmitter really designed for true full system redundancy. Even with failures, a station must stay on the air, so having a transmitter designed with redundancy as the first criteria is critical.
Concepts of efficiency are often discussed, but not always understood.
Busi: Some manufacturers specify the PA efficiency, ignoring the energy losses in power supplies, fans, IPAs and even in combiners and splitters. It’s easy to be fooled – ask specifically for the total AC load, with the fans running, at the rated power output.
However, highest efficiency is not the only criteria. Take for example a 10 kW FM transmitter at 72% efficiency versus 75% efficiency. In most cases it will save about $50 a month, but pushing a transmitter to its limit may cost you a lot more if something fails, or the performance is not 100%.
Get the highest efficiency you can, it does save money; but do not let that be the only reason of selection. Often a manufacturer will obtain a high efficiency by “squeezing” the MOSFET device, but this produces an internal thermal heat reaction that reduces the life of the device itself.
When designing an RF amplifier you must consider the temperature of the device in the worst climate, not the “optimum” climate. For example, your transmitter should be designed to operate in an environment of at least 45° C or 113° F. Most producers consider the room temperature 25° C or 77° F, as if it were a consumer product! A broadcast transmitter site should be considered closer to a military application rather than that of a consumer installation. Elenos and BE transmitters have the right efficiency and performance algorithms for the right room temperatures, keeping the maximum efficiency but not compromising reliability.
What features stand out as notable recent additions?
Busi: In our latest design transmitter, to be released very soon, we will introduce a giant step in redundancy and simplicity, significantly reducing the need for highly trained engineers to travel to the transmitter site as often, and therefore dramatically reducing the cost of repair, transportation.
In addition, all our transmitters in the future will include a software-defined modulator and central control system.
The pace of change in our industry is increasing, and the ability to adapt to future change by installing a firmware upgrade makes tremendous sense.
How will designs change in the next five years?
Busi: Artificial intelligence will be incorporated in new designs so that the equipment will learn from the environment, and optimize their own parameters to maximize reliability, performance and efficiency.
They will also be able to self-diagnose issues before they cause failure and recommend corrective action. It will become standard to have advanced warnings and suggested solutions. They will include the latest concepts in redundancy, and they will be made that they are so exceptionally simple to upgrade, repair and maintain, that a highly qualified RF engineer will not be needed to go the site every time to do even more complex repairs or maintenance.