Is VHF the Answer to the Spectrum Crunch?

Last week Lectrosonics announced the release of the IFB-VHF, a 174-216 MHz tuned version of their popular IFB-UHF system.

(Which, by the way, has nothing to do with, and does not look like, the vintage marketing image from the old manufacturer Vega, shown above, and plenty more here.)

Of the new product, Lectrosonics President Karl Winkler said: “By adding the IFB system on the VHF frequencies, it allows users and system designers to move these out of the critical UHF band, which should improve the ability to coordinate larger systems even in a crowded RF environment.”

Lectrosonics is one of the first—but certainly not the last— major wireless audio manufacturers to reintroduce products in the VHF (30-300 MHz) band in an effort to ease the RF congestion at every large-scale production in UHF, and get a running start on the incentive auction’s decimation of 40-50% or more of current UHF spectrum available.

So far, these early second wave VHF devices are all non-performance devices—devices that wirelessly transmit some sort of audio or control that is not heard by the audience. (I say second wave because wireless audio began in VHF, and then migrated up to UHF in the mid to late 90s.) The only other major player to go VHF has been Radio Active Designs, with their successful UV-1G intercom system. There are no wireless microphones or monitors yet in VHF, though we might see some drop down to VHF sooner or later.

The announcement from Lectrosonics last week has got us thinking about VHF in general.

How suitable is it to performance and non-performance wireless audio gear?

What are the benefits of VHF over UHF?

And, crucially, if those benefits exist, can we expect them to last?

[NOTE: This discussion is mostly relevant to the United States and VHF spectrum in the US. Other regions may have different VHF allocations.

What is VHF?

“VHF” is defined by the ITU as radio waves between 30 MHz to 300 MHz. Go ahead and get yourself oriented with this supersized spectrum map.

Wireless audio users are not allowed free range across all 270 MHz that VHF theoretically offers. We are confined to empty VHF broadcast band DTV channels.

In a location where there are no VHF DTV channels, there are 76 MHz of spectrum available.

I want to repeat that. In the best case scenario VHF offers only 76 MHz of spectrum. By comparison, UHF currently offers 220 MHz, and 2.4 GHz around 86 MHz.

The VHF TV broadcast band is also non-contiguous; it is split into three bands (the highlighted blue bars in the chart above) containing 16 DTV channels separated by other services. “Low band” VHF, “mid band” VHF, and “high band” VHF. Low band extends from 54-72 MHz, mid band from 76-88, and high band from 174-216 MHz. Because the separation between low and mid band is so small (only 4 MHz) some lump both low and mid band VHF into simply “low band VHF” and call it 54-88 MHz.

The Pros of VHF

• Lower Traffic
  At the moment, VHF has fewer devices and fewer TV stations in it than UHF. During the DTV transition, many TV stations migrated up to UHF, abandoning VHF due to concerns over interference. Every major wireless audio manufacturer abandoned VHF by the mid 90s, so aside from RAD, Lectrosonics, and a few other products you might encounter on a production, like Comtek IFBs, VHF is a veritable oasis of solitude for low power wireless audio devices like wireless microphones and in-ear monitors. This is the main draw to VHF, and make no mistake: it’s a big one.

• Better Range
  Because of the propagation characteristics of VHF frequencies, signals are able to carry farther with the same amount of transmission energy than they are at UHF. Well-designed VHF equipment, operating with the same transmitter power, under the same conditions, and the same gain antenna, will travel farther than a UHF signal.

• Less In-Line Attenuation
  The generosity of VHF propagation extends into coaxial cables, too. You get much less in-line attenuation (signal loss inside cable) with VHF equipment than you do with UHF, which means you can do longer coaxial cable runs with fewer or no amplifiers, and use less expensive types of cable and expect the same performance.

Cons of VHF

• Larger Antennas & Components
  This is probably the biggest hangup. Because VHF frequencies have longer wavelengths, the devices themselves tend to be larger, heavier, and more expensive if they are engineered to the same quality standards as current-day UHF gear. For example, the wavelength of 180 MHz is about 5.5’. Whereas a 550 MHz signal has a wavelength of only 1.8’.

  Because of the long wavelengths of low band VHF (54-88 MHz), it’s unlikely that we’ll see much, if any, performance equipment manufactured there at all. Designing the antennas and electronics for a flawlessly reliable wireless microphone or in-ear for low band VHF are practically impossible without resorting to some wacky, expensive, and aesthetically unappealing tricks.

Non-performance equipment, like IFBs and intercoms however can use low-band VHF, since the audio quality of the audio feed is less critical. Comtek already offers a few products in that range.

• Incentive Auction Uncertainty
  There are still TV stations that use VHF frequencies. Most of them are public access or low power TV stations. But others may return.

  One of the “incentives” built into the incentive auctions is the option for a broadcaster to swap their UHF license for a VHF license and still get a payout. How many broadcasters will bite on that worm is yet to be seen. It’s possible that an uncertain number of current UHF stations will take the bait and move down to VHF, further crowding what is (remember) only 76 MHz.

• Low Power Pig Pile
  If all wireless audio manufacturers suddenly started making lots of gear in VHF, we’d have a problem.

  As James Stoffo once told me, “VHF is like that bar that used to be crowded, but now no one goes to anymore. There’s nothing wrong with the bar—it’s just that people have the perception that it was crowded, so they don’t go there anymore.” 

  If people (manufacturers) started going to the VHF bar again in droves, it would get crowded. And it would get crowded a lot faster than it took to crowd up UHF, because of its relatively small size.

  It might be argued the pig pile problem has happened in the last 1-2 years at 2.4 GHz. Since 2013, just about every major manufacturer has rolled out a 2.4 GHz band microphone.

  The result?

  It is very difficult to use multiple channels of 2.4 GHz microphones in any realistic venue. If you only need one 2.4 Gig mic—you’re fine. But need four, eight, or 12 channels of 2.4 wireless? Don’t look to tech support to solve that problem, look to religion; the 2.4 GHz ISM band is simply too utilized, even without adding a spectrum hogging microphone to the mix. WiFi and bluetooth devices use 2.4 GHz spectrum, too, and their use has exploded at 2.4 GHz even more than wireless audio.

• Higher Noise Floor
  In most locations, the noise floor at VHF is slightly higher than it is at UHF. The difference, though, is small. And the noise floor in a large-scale production is always going to be elevated.

IS VHF the Answer?

VHF is not “the” answer to wireless audio’s impending spectrum shortage. But it is one of several answers that, combined, will lead us out of the darkness ahead.

Future regulatory and technological seismic shifts will not allow us to keep all of our equipment exclusively in UHF for much longer.

Instead, the numerous low power wireless devices used in large-scale productions will have to fan out across the spectrum in combination with the correct deployment of tools like external antennas, filtration, and new modulation schemes if we are to continue to use them in the same quantities.

There is almost no other alternative.

Luckily, we’ve got RF options. We have VHF, we have the unlicensed bands at 900 MHz, 1.9 GHz, and 2.4 GHz, as well as (debatably) 5.8 GHz. There are plenty of additional bands open to holders of Part 74 and Part 90 licensees, as well as new bands that are slated to open to license holders post-auction, including the 169–172 MHz band, the 944–952 MHz band, the 941– 944 MHz and 952–960 MHz bands, the 1435–1525 MHz band, and the 6875–7125 MHz band. More on those here.

We won’t be kissing UHF goodbye, at least not yet. We’ll just be saying hello to unfamiliar spectrum elsewhere, making wireless production band-planning far more fragmented, but still doable.

Want better wireless? Download our eBook on three essential concepts for correctly deploying and maintaining interference-free wireless audio systems.

Shure Europe Now the Exclusive Distributor of RF Venue Products In Europe, Middle East, and Africa

Today, we’re excited to announce that Shure Europe and RF Venue, Inc. have entered into an exclusive distribution agreement across the EMEA regions.

Shure Europe’s regional distribution offices in Germany, the United Kingdom, and BeNeLux – alongside Shure Europe’s third party distribution partners across EMEA – will now distribute and sell RF Venue antenna and signal distribution products..

“We’re pleased to partner with the world’s leading wireless audio brand to bring RF Venue products to EMEA regions,” our CEO Chris Regan commented. “Shure Europe’s marketing, distribution, and fulfillment capabilities will provide RF Venue customers in those regions the highest level of sales and support. RF Venue products are highly complementary to Shure wireless systems, so this agreement is a great fit for both organizations.”

Over the last two years, we’ve seen our international base of customers increase substantially. Reduced UHF spectrum and the overall increase in number of wireless microphones has been a worldwide trend, and audio professionals everywhere realize that operating demanding wireless systems requires superb tools, like those that RF Venue and Shure offer, while still remaining cost-effective.

Our distribution agreement with Shure Europe will give those customers—both existing and new—faster and more complete access to RF Venue products and support, in their home countries and native languages.

“RF Venue antennas and distribution systems complement our extensive Shure wireless offering very well,” said Ron Marchant, General Manager Shure EMEA. “This distribution partnership strengthens our wireless market position across the EMEA region by offering a more comprehensive set of RF solutions for the most demanding applications. We look forward to working with RF Venue going forward.”

Region specific information on RF Venue products can now be found on the Shure EMEA and UK websites.

Shure UK

Shure BeNelux

Shure Germany

*Leading image courtesy Shure EMEA.

WRC-15 Upholds UHF Broadcasting and Wireless Microphones As Services of Value – In Europe, Asia, and Africa – For Now

The World Radio Congress (WRC) is held every few years by The International Telecommunications Union (ITU), who invite an esteemed congress of delegates from 193 member states (FYI, only three countries are missing) to discuss and vote on wide-ranging and critical topics relating to radio and telecommunications.

WRC-15 concluded on the 27th of November, lasted an entire month, spanned 40 topics, and was attended by 162 of the 193 Member States.

Among those topics was a debate on the continued relevance of terrestrial over-the-air television broadcasting.

Although the topic was low on the priority list, it was still on the agenda, and it had its day in the sun.

As reported by the EBU:

“…representatives reached a consensus that this spectrum, currently used by broadcast services such as digital terrestrial TV [DTT] and radio microphones, is too important to be allocated to mobile services. They agreed that there would be no change to the allocation in the 470-694 MHz band either now, or at WRC-19 in four years’ time. Instead there will be a review of the spectrum use in the entire UHF band (470-960 MHz) at the WRC in 2023. Only then will it be decided whether to make further changes to the Radio Regulations.”

The EBU is an interest group similar to the NAB, so their interpretation of the representative’s consensus is upbeat.

This could be taken as good news for traditional broadcasting everywhere and, by extension, wireless microphones that operate in UHF spectrum, but many organizations seemed to have overstated the positive ramifications of the decision for the United States.

The NAB was even more blunt and politically charged than the EBU in a statement released yesterday.

“NAB was pleased by the global unity demonstrated at WRC-15 for the importance of a vibrant system of over-the-air broadcasting. Of the 162 nations attending the conference, more than 140 countries rejected the wireless broadband industry’s anti-broadcasting UHF spectrum grab and recognized that frequency band is harmonized to provide television services on a worldwide scale. This broad consensus should send a strong message that while wireless broadband services are important for those who can afford the fees, that service should not come at the expense of a ubiquitous over-the air TV service that is available to all for free.”

Yet this statement seems odd coming from an American organization, because America was not part of that “global unity.”

The ITU’s decision to safeguard the UHF broadcast band until 2023 was agreed upon only in Region 1—Europe, Africa, and Asia. North America and the United States are in Region 2.

Any positive windfall for broadcasters from WRC-15 will not be felt here in America.

It seems that the ITU has identified UHF OTA broadcasting as a radio service and spectrum allocation worth saving in the absence of other alternatives, and that preserving the UHF band for broadcasting is part of a longer term transition to other mobile internet/broadband services.

As long as the digital divide exists, OTA broadcasting plays a critical role in delivering information and entertainment to impoverished, disenfranchised, minority populations, as well as the general public in times of peace and disaster, free of charge.

But the digital divide is unlikely to last forever.

As described in the Lamy Report given to the European Commission in 2014, terrestrial broadcasting is recommended to exist in tandem with mobile broadband, and a reassessment of the UHF allocations from broadcasting is suggested to commence in 2025, right around that second to next WRC conference in 2023.

The United States, meanwhile, has the workings of some sort of mechanism to close the digital divide within its own population through the Connect America Fund. In their own words: “Broadband has gone from being a luxury to a necessity for full participation in our economy and society – for all Americans.”

Oh, and did I mention?- Google, Facebook, and Elon Musk have already launched balloons, satellites, and high altitude drones to blanket the earth with broadband internet coverage—free of charge to those who can’t afford it.

This morning, there seemed to be widespread jubilation among the broadcasting community at the WRC-15 outcome on terrestrial broadcasting in Region 1. But I think that jubilation jumps the gun.

Sure, the ITU is a big deal. What they say and do matters. And as an intergovernmental body they in some cases define the technical and legal standards by which radio and telecommunications activities are conducted globally, and in others, make powerful recommendations that participating states usually heed.

The coverage casts the illusion that the WRC-15 decision will somehow percolate from the roundtable at Geneva, cross the Atlantic, and infiltrate the minds of congressmen and women—wrenching them awake from their wireless broadband industry induced stupor to the daylight reality of the power of over-the-air TV in 2015.

The disparate connection between opinions on the importance of broadcasting in Region 1 and Regions 2 and 3 could also allude to a concerning trend: global disharmony and the US as lone wolf.

The United States picks and chooses what to align with on the international consensus on spectrum policy, sometimes following, sometimes affirming, but leading less often than it historically has—and receiving more pushback on what it proposes when it does decide to lead.

America and the FCC wants to lead forcefully as an agent of global peace through power, and, critically, power through superior technology. Spectrum technologies, and spectrum regulation concepts originating in the United States are a small, but still real, component of our assertion of influence on the global stage.

But what was missing from the US broadcaster reaction of the consensus at WRC-15 was not that a consensus on preserving the UHF for broadcasting was reached. It was that the United States was not part of that consensus; the resulting agreement (which as I understand it does not have the binding authority of international law) was a fragmentation of member states on the allocation of the remaining UHF band, with the U.S. dragging Region 2 into the minority due to its hellbent quest to recover UHF spectrum via the incentive auctions—an ingenious but unproven mechanism planned by no other nation.

In preparation for WRC-15, US delegates issued this proposal in March, which I found through the NTIA:

Recognizing the growing need for mobile spectrum below 1 GHz, the current deployment and future development of broadcasting systems, and the differing national priorities of the member states as regards UHF broadcasting, it is necessary for WRC-15 to adopt a regulatory solution that would:

• Enable administrations to preserve and protect broadcasting and other services in the UHF range,
• Consider ways to facilitate the development of future broadcasting systems, and
• Allow administrations flexibility to address the mobile spectrum shortage consistent with their domestic requirements.

To achieve these objectives, the United States proposes modifications to the Radio Regulations that would add an allocation to the mobile services and identification for IMT in the range 470-694/698 MHz except for the 608-614 MHz band in Region 2. The United States also proposes retention of the primary allocation to the Broadcasting Service in the 470-890 MHz frequency range, including the mandatory application of No. 9.21, which would ensure that the existing services, such as broadcasting, maintain coordination priority (i.e., remain super-primary) vis-à-vis IMT systems.

Further…

Globally harmonized allocations to the mobile service in the 470-698 MHz frequency range would enable introduction of innovative broadband services while preserving access to spectrum for the existing services, such as broadcasting. A new allocation to the mobile service would provide administrations with the flexibility to maximize spectrum utilization.

As the EBU release makes clear, the rest of the world did not agree with the United States’ proposal that the UHF band should become new home to mobile broadband services. They rejected the proposal because terrestrial broadcasting in Europe, Asia, and Africa is important in ways that we, isolated by two oceans, and richer than any other country in the world, cannot fathom.

I think it’s important to recognize that that rejection by consensus does not by default mean the United States will follow suit in preserving the remaining licenses of OTA broadcasters between the commencement of the auctions next year and 2023.

To conclude, and in other words, we are not on the same page with the rest of the world when it comes to OTA broadcasting, and that means broadcasting (and wireless microphones) are still in immediate danger of disruption, even though we have traditionally led the world in efforts to “harmonize” allocations, as well as other issues that I am not as qualified to discuss.

Is that because United States policy is so far advanced beyond the ITU’s comprehension that it can it afford to dissent or contradict proposals from delegates from the other 192 ITU member states?

Or is it for some other more alarming, sinister, or dysfunctional reason that we blaze our own trail?—ahead, or behind.