Worldcast Systems - Radio & TV Broadcast Solutions

Building a greener landscape for FM

To support radio broadcasters in meeting their sustainability goals and economic challenges, WorldCast Systems developed SmartFM, a worldwide patented software that enables up to 40% lower energy consumption of FM transmitters.

Global CO2 emissions from energy combustion and industrial processes rebounded in 2021 to reach their highest ever annual level, according to a March 2022 report from the International Energy Agency. In total, more than 36 gigatons of emissions were pushed over the air in 2021, a 6% increase compared to 2020.

Combined with worldwide increases in electricity costs, sustainable energy has become one of the greatest challenges facing radio broadcasters.

In the broadcasting chain, the transmitter represents the most impactful equipment as it continuously delivers a fixed output power to the antenna. In the FM chain, transmitters go from a few watts to dozens of kilowatts depending on the coverage area, landscape, and radio listeners’ profile.

To reduce FM transmitters’ energy consumption, the first step is to ensure highest efficiency. After years of innovation and the integration of state-of-the-art technologies such as the most recent LDMOS devices and PSUs, FM transmitters have nearly reached their maximum efficiency in terms of physical components. Therefore, it is necessary to rethink the concept of FM broadcasting by building upon the already incredible performances of transmitters and receivers.


A common misconception is to think that the technical objective of an FM broadcast chain is to transmit at a specific output power to cover a service area, but the real objective is to deliver high-quality and constant listening comfort for listeners over the entire service area.

Listening comfort can be summarized as the signal-to-noise ratio. Is the listener disturbed by the noise? Listeners’ audio perception of the same noise ratio varies depending on the type of audio content. For example, with speech programs, the slightest disturbance will have a negative impact on listening comfort. With highly processed music (covering the full audio spectrum), the noise will be easily covered by the signal itself. It is then possible to slightly reduce the signal-to-noise ratio without impacting audio perception.

WorldCast Systems developed SmartFM based on this concept. It employs a psychoanalysis algorithm to qualify the robustness of audio content to perturbations. When the signal is robust enough, AI adjusts the transmitter power accordingly. This results in up to 40% electricity savings while maintaining listeners’ comfort and service.

Another impact of SmartFM is to reduce the average heat dissipation of the transmitter, reducing the cooling system’s electricity consumption proportionally.  

For example, the efficiency of a 10kW FM transmitter is about 74%, which means that the direct electrical consumption is approximately 13kWh, 24/7. Total electricity consumption to feed one 10kW FM transmitter during one year is then estimated at 120MWh. With SmartFM, total consumption for the same system drops by 10% to 40% - a maximum reduction of 50MWh per year for a 10kW FM transmitter. This represents an annual saving of 18 tons of CO2 (for Europe where average annual consumption is 71 tons).

To help broadcasters reduce the electricity consumption of their FM transmission network and improve their carbon footprint, the industry must rethink the whole concept of radio broadcasting and continue to find new ways to innovate. WorldCast Systems will continue to play a key role in enabling positive, technology-led change.


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