Introduction
Coordinating radio frequencies across an event that spans a small city is a complex but critical task in festival production. Imagine a multi-stage festival or city-wide event with dozens of wireless microphones, in-ear monitors (IEMs), intercom systems, and wireless cameras all competing for space on the RF spectrum. Without careful planning, these devices can interfere with each other – causing dropouts, noise, or complete communication failures. Whether it’s a music festival stretching across downtown blocks or a sprawling outdoor event site as large as a town, RF coordination ensures that every wireless signal finds a clear channel. It’s a behind-the-scenes art and science that separates a seamless show from a chaotic one.
Festival producers around the world – from the United States and Mexico to the UK, Australia, India, and beyond – increasingly recognize the importance of professional RF management. Large events like Glastonbury in the UK or Coachella in the US employ dedicated RF coordinators, and even smaller regional festivals benefit from these best practices. The goal is simple: deliver interference-free sound and communication to performers, crew, and audiences. Achieving that goal, however, requires discipline, technical know-how, and the strategies outlined below.
Appoint a Dedicated RF Lead with Authority
The first step in city-scale RF coordination is to designate a single RF lead – an individual or team responsible for managing all wireless frequencies event-wide. This RF coordinator acts as the airwaves traffic controller, ensuring that every stage and department (audio, video, communications, etc.) operates on assigned frequencies that won’t conflict. Giving one qualified person the authority to assign and approve frequencies across all wireless mics, IEMs, intercoms, and cameras prevents different teams from inadvertently stepping on each other’s signals.
Having an official RF point-person is standard at major festivals. For example, large-scale events often see hundreds of wireless channels in use simultaneously, from artist microphones to production communications. In such scenarios, a dedicated coordinator is indispensable – they maintain a master frequency list and can veto or reassign any channel that poses a conflict (www.sounddevices.com) (www.prosoundweb.com). This central authority also streamlines communication: touring engineers, vendors, and local crews all have one expert to consult for any wireless needs. It fosters a “big picture” frequency plan rather than siloed approaches by separate teams.
Critically, the RF lead should begin coordination early, well before the event. They’ll gather frequency requirements from all performers and vendors, then use coordination software (or meticulous manual planning) to map out a spectrum allocation that accounts for local regulations and avoids intermodulation issues. Every transmitter – from a singer’s handheld mic to a roving camera’s video link – should get a slot in the master plan. If an artist arrives with unexpected wireless gear, the RF lead checks it against the plan and either finds it a safe frequency or replaces it with event-provided equipment. This proactive oversight averts on-site surprises like two stages unknowingly using the same mic frequency.
Another advantage of an authoritative RF lead is managing rogue or unplanned transmitters. In a “small city” festival environment, it’s not uncommon to discover a nearby wireless user that wasn’t in the advance plan – for example, a local media crew or a pop-up stage. A vigilant RF coordinator will scout the venue and its surroundings for any such devices. In one Canadian festival, the RF lead even discovered a small, unlisted side-stage where a local radio promotion had set up two wireless microphones (www.prosoundweb.com). He noted their frequencies and adjusted the main stage’s in-ear monitor channels to ensure there was no overlap or interference. Without a single coordinator looking out for all wireless systems, these kinds of hidden conflicts could easily disrupt a performance.
In summary, appointing one experienced person (or integrated team) with ultimate authority over the wireless spectrum is the foundation of RF coordination at scale. It creates order out of potential chaos, much like an air traffic controller managing dozens of planes. The festival’s various technical departments must all respect the RF lead’s assignments – this top-down approach is essential to avoid a free-for-all that could jam the airwaves.
Test in “All-On” Show Mode for Interference
Planning frequencies on paper (or software) is only half the battle – the real RF environment comes to life when all devices and systems are powered on. That’s why it’s crucial to conduct tests in “all-on” show mode, meaning every wireless transmitter, piece of sound gear, lighting rig, LED wall, and power circuit is turned on exactly as it will be during the live event. This full systems test often reveals interference sources and noise issues that might be missed in isolated checks.
One common culprit is LED lighting and large video walls. Modern LED fixtures and screens use high-frequency switching power supplies that can emit broad-spectrum electromagnetic interference (EMI). On an empty stage with lights off, your wireless mics might look perfectly clear. But when you turn those LED lights on, you could see a significant spike in the noise floor – occasionally raising it by 10–15 dB and effectively drowning out wireless mic signals (www.rfvenue.com). Power distro systems, neon signage, motors, and even charging stations can similarly introduce RF noise. The only way to catch these issues is by replicating show conditions: lights at full brightness, sound systems up, all wireless packs on, and even any nearby generators or large electrical devices running.
During the all-on test, have the RF lead perform a thorough frequency scan of the spectrum being used. This scan will show any unexpected signals or noise across the bands. Walkie-talkies, Wi-Fi channels, and distant TV broadcasters might also appear during this full test. It’s far better to identify a problem now – perhaps an intercom system that crackles whenever the big LED screen displays white content – than during a live show. For example, an event in Singapore found that a high-powered video wall introduced interference on certain UHF mic channels only when displaying bright content; the solution was to slightly tweak those mic frequencies during rehearsals once the issue was observed in all-on testing.
The all-on rehearsal or soundcheck is also the time to verify that multiple stages operating concurrently aren’t interfering with each other. In a city-spanning festival, stages might be far enough apart to use similar gear without issues, but overlapping coverage zones can happen. If two stages are within earshot or line-of-sight of each other, a powerful transmitter at Stage A could still reach Stage B’s area. Testing all stages’ wireless systems at the same time – a full RF dress rehearsal – allows the coordinator to observe any inter-stage interference. If a problem arises (for instance, a guitar wireless from one stage breaking squelch on another stage’s receiver), the RF lead can immediately adjust frequencies or power levels as needed.
In summary, don’t skip the full systems RF test. Turn everything on as if the show were in progress: every mic, IEM, intercom pack, lighting fixture, screen, and generator. Have your RF coordinator scan and listen for noise or hits. This proactive step will catch environmental RF noise (like that from LED lighting) and any interaction between systems, giving you time to fix it – whether that means swapping out a problematic light, adding a filter, or simply shifting a couple of frequencies to cleaner channels.
Keep Backup Frequencies and Label Them per Stage
Even with rock-solid coordination and thorough testing, live events are dynamic. A frequency that was clear during rehearsals could encounter unexpected interference mid-show – perhaps a surprise local transmission or a piece of gear failure. Prepared festival producers always have backup frequencies ready for every critical wireless channel. A backup frequency is a pre-vetted, intermodulation-safe alternative that you can switch to on the fly if trouble arises. Keeping these backups documented and labeled for each stage ensures that the audio crew can respond in seconds to an RF problem rather than scrambling for a solution.
In practice, the RF coordinator will generate one or two backup frequency options for each wireless system during the planning phase. These should be included in the frequency coordination chart or database. For example, if the lead vocalist’s mic on Stage 2 is primarily assigned to 556.500 MHz, the plan might designate 558.125 MHz as “Mic 1 backup.” The transmitter and receiver can even be pre-programmed with this alternate channel stored in memory. A physical label or color code on the mic or beltpack can also indicate its backup channel for easy reference.
It’s important to isolate backups by stage or area. This means the backup frequencies for Stage 1 should ideally be unique to Stage 1, and not in use anywhere else unless absolutely necessary. By partitioning backup pools per stage, you avoid a scenario where triggering a backup on one stage inadvertently conflicts with another stage. At an international multi-stage festival (for instance, in Australia or Germany), RF teams often partition the spectrum – Stage A uses one range of frequencies, Stage B uses a different range, etc. They then select backups within those ranges to keep things compartmentalized.
Documentation is key. The RF lead should distribute a frequency sheet to each stage’s audio leader that clearly lists all primary and backup channels for that stage. When something goes wrong – say a presenter’s wireless mic starts getting hit with interference – the engineers can quickly mute that mic, switch both transmitter and receiver to the pre-assigned backup channel, and resume the show. Because the backup was coordinated in advance, everyone can be confident it won’t step on any other wireless device. This process might take 30 seconds instead of several minutes of panic, and the audience may never even notice a hiccup.
Beyond just frequencies, consider preparing backup hardware for crucial links. For example, have a spare handheld mic or beltpack tuned to the backup frequency, ready to hand to a performer if their primary fails. Similarly, spare IEM packs can be kept on standby. By labeling these spares by stage (e.g., “Stage 2 Spare Vocal Mic – Channel 38”) you reduce confusion during an emergency swap. In the high-pressure environment of a festival, clarity and preparation save the day.
Log Intermodulation Issues and Solutions for Next Year
One hallmark of veteran festival teams is that they learn from every event. Wireless spectrum behavior can change year to year – new telecom services roll out, venue infrastructures change, or you might get a one-off interference from a nearby source. By logging any RF issues encountered and the solutions implemented, you create a knowledge base that makes future coordination easier and more robust.
Right after the festival (or even during, stage by stage), have the RF lead maintain an RF log. This can be as simple as a notebook or as structured as a spreadsheet or database. Key things to record include:
– Interference incidents: Note the date/time, stage, which frequency was affected, and symptoms (dropout, noise, loss of range, intermodulation artifacts, etc.).
– Potential cause: If known, record what was believed to cause the issue. Was it intermodulation between two specific transmitters? An unscheduled device appearing on that frequency? An environmental factor like a weather-related range drop or local TV station bleed?
– Resolution: Document what action was taken to fix the problem – for example, “switched performer’s mic to backup frequency 556.875 MHz” or “found IEM pack with loose antenna, replaced pack”, or “repositioned receiving antennas away from LED wall – interference cleared.”
– Observations: Any additional notes, such as “interference occurred only after 10 PM – possibly due to distant TV transmitter becoming active” or “noticed two cameras on adjacent frequencies causing intermod spikes in spectrum”.
These notes are gold when planning the next year’s festival. If, for instance, the log shows that a certain frequency range consistently gave trouble at Stage 3, the next year’s coordinator might avoid that range entirely. Or if intermodulation between specific devices was an issue, they can plan more spacing or ensure those devices aren’t used in that combination again. Trends may also emerge: perhaps every year around a certain time, a local taxi dispatch transmitter briefly interferes with the range your crew intercoms use – a logged pattern like that allows you to adapt (maybe changing the intercom channel or adding filtering).
Additionally, sharing the log with manufacturers or RF consultants can help diagnose tricky problems beyond the event. Sometimes an equipment firmware update or an improved antenna setup (learned in hindsight) can be identified and implemented for next time.
Logging issues isn’t only about solving technical problems; it’s also about continuous improvement of protocols. For example, if the log shows that a backup frequency saved the day on multiple occasions, that reinforces the importance of having those backups. If it shows that some issues arose from lack of enforcement (e.g., a vendor turned on an unapproved wireless device), then producers know to tighten communication and oversight next year.
Finally, the log becomes part of the festival’s institutional memory. Festivals often involve new staff or contractors each year, but a written record ensures hard-won knowledge isn’t lost in turnover. Next year’s RF lead (if it’s someone new or a returning veteran) can review the document well in advance. It primes them on local RF quirks – perhaps the venue has an odd RF reflection spot or a neighboring TV channel that comes in strong at night (www.prosoundweb.com). Armed with this historical insight, the coordinator can design a frequency plan that circumvents known pitfalls, and allocate extra testing or gear where needed.
Key Takeaways
- Centralize RF coordination under one lead: Always assign a single RF coordinator (or team) with the authority to manage all wireless frequencies across the event. This prevents conflicts and ensures a cohesive strategy rather than siloed, competing wireless setups.
- Simulate full show conditions for testing: Don’t rely on partial tests. Run an all-systems-on rehearsal with every wireless device, LED wall, lighting fixture, and power source active. This “all-on” test will reveal hidden interference (like LED-related RF noise or inter-stage clashes) that you can fix before showtime.
- Prepare backup frequencies (and gear): For each stage and each critical wireless channel, have pre-coordinated backup frequencies ready. Document them clearly and label equipment so that if interference strikes, you can switch to a backup channel in seconds without guessing.
- Document issues for the future: Keep a log of any RF problems, interference sources, and solutions encountered during the festival. This record will be invaluable when planning the next event – helping you avoid repeat problems and refine your coordination plan year over year.
- Adapt to local conditions and rules: Remember that different regions have different RF environments and regulations. Work with local authorities (such as Ofcom in the UK or FCC coordination in the US) if needed, and account for local TV stations, communications services, and geography in your frequency plan. A city environment can present unique challenges (reflections, intrusive signals) – learn and adjust each time.
By following these practices, festival producers can master the art of RF coordination even across a “small city” footprint. The result will be a reliable wireless experience for artists, crew, and attendees – ensuring technology never steals the spotlight for the wrong reasons.
25th August 2025