Here’s what you need to know about broadcast RF and other “surprise guests” at events.


Often when I hear reports of RF interference at a show, the description includes the line, “It just came out of nowhere!” 

video camera - RF wireless strategies

If you see one of these at an event you’re working, it’s time to pay extra attention to the RF situation.

Actually, where it probably came from is a van or SUV with the name of a local TV station emblazoned on the side. Here’s what you need to know about broadcast RF and other “surprise guests” at events.

1. Who is bringing these wireless devices to the event?

Typically, they’re either news crews (a.k.a, ENG, short for Electronic News Gathering) or videographers that have been hired to document the event (a.k.a, EFP, short for Electronic Field Production).

2. What devices are they bringing in?

In the case of ENG crews, count on at least one or often two transmitters (one bodypack and one handheld) per crew. These can be on one (or two) different Tx (transmit) frequencies.

Further, if they’re accompanied by a field van or uplink truck, they may also have one (or sometimes two) IFB (interruptable foldback) systems, which are the little earpieces that the reporter wears to hear the “throws” from the station.

These systems are almost universally Lectrosonics IFBT4’s, which work and sound great, and have a whopping 250 mw output. That’s how it can cover the distance from a van on the street into a venue. For comparison, a Shure PSM-1000 IEM transmitter puts out 10, 50 and 100 mw on low, medium and high power settings, respectively.

Meanwhile, the wireless microphone transmitters are often the plug-on type, with the most common makes being Lectrosonics, Sennheiser, and Sony, with an occasional Shure as well. An EFP crew may have as little as one transmitter and receiver or an entire bag (a pouch the sound people wear around their necks) or cart system with as many as eight or more transmitters.

The author’s message at events where he’s handling the RF/wireless.

3. How likely is it that they will show up at an event?

It really depends on the type of event. For example, when I parachuted into the Shania Twain Rock This Country tour in 2015 to manage wireless/RF, one of the first questions I asked the management team was what kind of media presence we could expect at each show. They told me “none” and I thought, “well, we’ll see…” In fact, I didn’t see one crew on the whole tour.

The point is that when working with artists of that caliber, they pretty much own the venue when you’re there and have complete say over who gets in and when. Note that this doesn’t prevent the media from doing “streeters” (a.k.a., person-on-the-street interviews) outside the venue, and it’s possible that this RF signal will get inside, albeit at a reduced level.

The same thing is true of large corporate events; however, there may be one or more documentary crews on site. In these cases, the crew had to be hired by someone and so, in theory at least, there should be someone like a production manager who is aware of their presence and can provide a heads-up so that their frequencies can be included in your coordination. I say “in theory” because the EFP crew(s) may be hired by a completely separate department (like the PR department) from the show production people.

Moving down the list, any event at which politicians are expected to appear either as speakers or distinguished guests are pretty much guaranteed to have ENG crews on site. This is especially true of sporting events, but public festivals also fall into this category.

4. You say that you work with a wedding/bar mitzvah band that only does art gallery openings, so you don’t have to worry about any of this, right?

Wrong! It’s extremely common for these events to have videographers present and they often have wireless systems. The Sennheiser ew100 G3 system with either a plug-on or beltpack transmitter is the one I see most often. Note that the receiver looks identical to the beltpack in this system, and the crews usually use much smaller cameras (like DSLR’s), so they may be harder to spot.

As well, if the weddings and bar mitzvahs you’re working include celebrities, expect the media to be on hand. Note that these ceremonies often take place in houses of worship, so if you’re the sound tech at the given worship venue, it’s a very good idea to have strong lines of communication with the person/team who books these events. Through that contact, you should (hopefully) be able to find out if there will be videographers at the ceremony and coordinate with them before they step on the bride or groom saying “I do” (or “maybe” or “can I text a friend?”).

5. Why are these crews more likely to step on our wireless channels than we are to step on theirs?

As noted earlier, the systems these folks use can have – and be set to – very high output power settings. And since they’re often transmitting over very short distances (usually just a few feet from the talking-head to the camera), nothing is going to interfere with them. Remember, with RF it’s whatever signal that gets to the receiver strongest that’s going to win.

I’ve often seen ENG crews show up with their RF systems tuned in the middle of an active, off-air DTV channel. I used to get excited about this and ask, “Hey, did you know you’re in the middle of an active TV channel?” and then move them to another frequency. Now, however, I’m more likely to leave them there because A) none of my channels will be in there, B) they don’t care, and C) their receivers are just going to see the DTV signal as an elevated noise floor that their transmitters are going to step over anyway.

6. OK, how do we spot these crews?

Apart from the obvious issue of having one of them land on or near one of the frequencies you’re using, they might pop up on a spectrum analyzer. However, for that to happen, you’d need to be scanning the whole width of the spectrum you’re occupying and be aware of all of your own transmitters. This can work if it’s a limited amount of spectrum, say 20 MHz for six wireless mics and six IEMs, but at the events I work we’re usually talking about at least 200 MHz and hundreds of frequencies.

This is why I’m a big fan of scanning in a much higher frequency range: visible light. That’s right, often the best chance of spotting these folks is keeping our eyes open and looking around. After a while, we start noticing different signs of them being present.

For example, if you see a heavy-duty tripod with no camera on it, it’s a pretty sure bet that a crew is nearby doing a “hit” (as they call it). Other times, you’ll see the tripod, a blue Cordura bag with a camera in it, and a well-dressed person standing around keeping an eye on the gear – while their camera person is parking the SUV.

World Cup of Hockey RF Coordination poster - RF wireless strategies

Posted notice regarding RF at the 2016 World Cup of Hockey, an international ice hockey tournament sanctioned by the National Hockey League (NHL).

Another tip-off is a camera with two closely spaced antennas on it. Shown in the photo that opens this article (top/right of this page), these two small whip antennas are the UHF Rx antennas. You may also see two other antennas on the back, which are for a wireless camera (video) signal. Of these two, the large rod antenna is the camera signal transmit (the picture), which operates in either the 2 or 5 GHz range, and the “rubber ducky” antenna on the back is the data or “paint” control for the camera (so it’s a receive antenna), which is in the 450 – 470 MHz “walkie-talkie” band. Note that typically we don’t need to be concerned about the last two, and that it’s very common to see cameras with those two antennas but without the UHF microphone receiver.

7. So, once we’ve spotted them, how do we deal with them?

Once again it depends on the event. For example, when I’m working a National Hockey League (NHL) outdoor hockey game, the league mandates that it has complete control over all wireless devices in use. In this situation, I have complete authority to A) ask what frequency a crew is using, and B) coordinate a new frequency and verify that the crew has switched to it and remain on it. I typically have the same leverage at political events.

In contrast, last summer at a four-day festival at a public square in downtown Toronto, I had virtually no authority to ask anyone to change their frequency while they were at large in the square, so the job became more of an “observe and report” scenario. I would approach the crews, find out what frequency they were on, check it against my coordination and then if necessary, work around it.

This situation does change somewhat if the crew decides to make use of the media risers provided by the event organizers (in this case, the city of Toronto). Then, I have authority. However, an important thing to note is that all professional video cameras have audio XLR inputs on them, so the best course of action is to explain the RF situation and request that they use an XLR out of the media pool feed provided on the riser.

Lately, I’ve begun requesting that the PA supplier provide plenty of XLR cables with the pool feed so that no camera person can use the old “Oops, I didn’t bring a cable!” dodge.

And dodge they will. I’ve found that while most of the ENG/EFP folks are cooperative and even appreciative of being given a frequency they can call their own, there’s still a certain number that try to talk or walk their way around it. There are a variety of reasons why, the most common one being that they’re always in a rush to get in, do their hit, and get back in the SUV to go to the next one.

Other reasons can be that they either don’t like to, or don’t know how to change frequencies, and/or that they’re assigned frequencies at the station that they’re expected to stick to. (These are usually marked on the camera, sometimes incorrectly. On several occasions, I’ve been asked to change a frequency back to the assigned one after an event, which I always do).

If they demand to know why they need to change the frequency, I often respond with, “Well, if your news report turns out to be that the star’s microphone failed during the performance, let’s make sure that it wasn’t your mic that caused it to happen in the first place!”

This article first appeared on www.prosoundweb.com