by Jay Patterson CAS
For more than five decades, radio transmissions have played an increasingly large part in the infrastructure of motion picture and television production, worldwide. In the greater Los Angeles production environment, the operation, management, and maintenance of radio transmitters has always been the explicit responsibility of IATSE Local 695. As clearly stated in the “AGREEMENT OF AUGUST 1, 2018, BETWEEN PRODUCER AND I.A.T.S.E. & M.P.T.A.A.C. AND LOCAL #695 THEREOF,” Article 1 Scope of Agreement, Paragraph 5: “It is recognized that the IATSE Constitution grants the following jurisdiction to the IATSE Local #695: Work of any nature in or incidental to the transmission of sound and carrier frequencies…”
The vast majority of bands in the spectrum are only to be used for specific types of transmissions, and require a license, granted by the FCC in order to legally operate a transmitter. There are also bands that allow “Intentional Radiators” (i.e.,—low-power transmitters), devices that do not require a license to operate. Examples of Intentional Radiators include but are not limited to cordless telephones; remote-controlled cars, planes, and drones; Wi-Fi, video links, and remote focus systems used by camera departments; and the broad range of DMX control signals used by special effects, media servers, and set lighting. Many of these devices operate in the 2.4 GHz and 5 GHz frequency bands. The federal regulations regarding the use of Intentional Radiators are contained in Title 47, Chapter 1, Subchapter A, Part 15, Subpart C, which can be found within the Electronic Code of Federal Regulations website (https://www.ecfr.gov/cgi-bin/text-idx?SID=d8fcd9a4dd2c890b5e400718cac89ab1&mc=true&node=sp47.1.15.c&rgn=div6#se47.1.15_1209).
Frequency coordination occurs on a massive scale every single day in motion picture and television production, be it on a studio lot or on location. Every single walkie-talkie, radio microphone, wireless camera hop, etc., is coordinated, enabling the devices to work together without interfering with one another. On a studio lot, this is usually handled by a Local 695 Coordinator, usually a Y-3A (Supervising Sound Engineer). On a scripted show, more than two dozen transmitters may need to be coordinated every day. Talks shows and reality programs might use upward of fifty. Coordinating a sporting event or an awards show becomes an Olympian task as more than a hundred different transmitters might be used at any given time.
It is significant to note that devices that are designed to operate in the 2.4 GHz and 5 GHz bands do not require a license to operate. In fact, there is no license available for the 2.4 GHz and 5 GHz spectrum, which is a portion of the National Wi-Fi Infrastructure Backbone established by the FCC. Due to considerations of range, penetration, and workable antenna lengths, the 2.4 GHz and 5 GHz bands are extremely popular bands for Intentional Radiator manufacturers. In the last several years, there has been a dramatic rise in the use of remotely-controlled everything in motion picture and television production. Generally speaking, devices that approach ‘real time’ operation in these bands rely upon ‘frequency hopping,’ where a device’s carrier is constantly changing. Different devices will use various ‘groups’ of frequencies to hop around on, thus enabling multiple devices to use the same range of available frequencies depending on their moment to moment needs.
Anecdotally, this technology was co-invented by the actress Heddy Lamar.
Several years ago, there were significant conflicts in production in the use of 2.4 GHz and 5 GHz devices, primarily between the wireless network-controlled DMX dimming systems and the wireless transmitters used by the camera departments to stream images from the cameras. This was a very real problem and an ad-hoc committee of users and manufacturers came together to address the issues. These discussions were initiated by the manufacturers of DMX lighting control devices, and all affected crafts and manufacturers were invited to participate, including Local 728, Local 600, and the Technical Trends Committee of Local 695. Various solutions were discussed and models of “coordinated behavior” were identified, primarily by drawing on the practical experiences of our counterparts in the world of theater. With so many theaters nestled so close together on Broadway, the stage industry had overcome the challenge of running fifty channels of wireless microphones, several channels of production communication, DMX control, and Wi-Fi, all without stepping on one another’s toes. The concept of “coordinated behavior” contains the practice of frequency coordination, along with the practice of using all transmitters at their lowest acceptable power level. As the 2.4 GHZ and 5 GHz bands are open to any properly manufactured Intentional Radiator, the committee could only recommend ‘best practices.’ Shortly thereafter, a practical solution was achieved by the manufacturers—the companies making wireless video for the camera departments would only operate in the 5 GHz band, and the DMX devices would be only in the 2.4 GHz band.
In terms of coordination, a simple phone call in pre-production between those crafts using the unregulated portions of the radio spectrum can effectively reduce the risk of interference between them. Along with identification of frequency groups used, if participants agree to transmit at the lowest acceptable ERP (radio energy transmitted from the antenna), multiple departments can and do share the Wi-Fi bands.
It is also paramount to note that these unlicensed Intentional Radiators are not allowed to cause interference to any licensed operation such was wireless microphones in the UHF (Ultra-High Frequency) band.
The FCC recently released a new online process for obtaining the Part 74 license, called Form 601 in the FCC’s Universal Licensing System (ULS). It is cross-platform and should run on any modern HTML 5 browser. Thanks to Bill Ruck in San Francisco and our own Laurence Abrams and Tim Holly, Local 695 is again sponsoring completely rewritten Step-by-Step Application Guide with detailed instructions from start to finish. If you have to obtain a license, please let us know your experience using the guide so we may improve it in future editions and make it as easy as possible to use.
In order to contribute to our database of entertainment professionals holding their FCC Part 74 licenses, please let us know if you hold a license. Send contact info and license number to email@example.com