Issue link: https://digital.copcomm.com/i/1530210
28 PRODUCTION SOUND & VIDEO – Winter 2025 framework that manufacturers must adhere to when developing technology and products that use WMAS transmission. It defines the spectrum emission mask and minimum system performance requirements. Many of the questions you might have about WMAS fall to the manufacturers' implementation of WMAS and not to the regulatory framework itself. For example, you might need to know how many channels can fit into one carrier? What happens if there is interference to the wideband channel? Would I lose all of my channels or just a few if there was interference? Do I have to use an entire 6MHz TV channel for each WMAS deployment or can I use a smaller section of spectrum? What is the audio quality of each channel? How much delay or latency can I expect? How much range does the system have? The answers to all of these questions would be dependent on how the framework is deployed by a given manufacturer. However, the WMAS standard can answer what frequencies can be used and maximum output power specifications. WMAS will still operate in the current available spectrum bands, including the AFTRCC 1.4 GHz band. One limit to WMAS frequency use is that each radio must only occupy one TV station (6MHz) and cannot overlap to adjoining TV channels. For example, if you have the upper 3MHz clean in TV channel 21 and need 6MHz total, you cannot use the clean, lower 3MHz of TV channel 22. In the AFTRCC 1.4 GHz, where up to 30MHz is permitted, users could operate one 20MHz WMAS system and one 10MHz WMAS system, or two 15MHz WMAS systems, etc. Unlicensed users are allowed a WMAS max system power of 50mW up to 1MHz wide and 100mW when your carrier is 1-6MHz wide. Part 74 licensed users are allowed the same power levels as narrowband carriers, typically 250 MW. Different manufacturers will implement this power in different ways. As with any new technology, there are pros and cons to the WMAS framework. On the positive side, WMAS has the potential to offer much better spectral efficiency than we currently have with narrowband carriers. It also offers the opportunity for physical hardware efficiency as well. The ability to do more with less hardware can reduce the need for large racks of equipment, saving both space and weight for audio departments on production, on tour, and on live events. The hardware designs will be manufacturer dependent, but WMAS offers the potential for a major shift in the need for rack space. A major advantage is the ability to deploy a high channel count. Large events such as major sporting events, large conventions, live theater, and reality TV—which all typically need hundreds and hundreds of wireless channels—will benefit greatly from the increased spectral efficiency that WMAS offers. When using traditional narrowband digital wireless in higher efficiency modes with sub 3ms delay, it's possible to reach up to forty- seven channels in 6MHz. WMAS can offer even higher channel counts in that same space. Channels can be as wide as 6MHz in the U.S. and 8MHz in Europe. A system is not required to use a 6MHz wide carrier, meaning a manufacturer could design a system that uses only a 2MHz or 3MHz wide RF carrier as long as it adhered to the minimum channel count of three channels per 1MHz. It may even be the case in the future that a WMAS system is manufactured that could be scalable based on the needs of the user. Another benefit that WMAS offers is bi-directional communication. While this is also going to depend on each manufacturer's implementation, a system could transmit IEM's and also transmit the talent microphones all within the same 6MHz carrier without any frequency separation typically created by a frequency coordinator. Frequency coordination is simplified because there is only one carrier to coordinate. While this doesn't eliminate the need for frequency coordinators or even properly choosing a clean frequency, it puts the coordination of each individual channel in the hands of the hardware. I know a lot of us don't like frequency coordination and it can be difficult in congested places like Los Angeles, so letting the box handle all of that will definitely make your RF life easier.