Broadcasters Eye A BAS Reboot

The time is right for a BAS overhaul. Old spectrum is getting new tools with private LTE and mesh networking as engineers and vendors create ways to achieve the same flexibility and two-way connectivity that bonded cell affords within BAS. Above, Silvus Technologies’ StreamCaster radio gives bi-directional IP connectivity for camcorders. Here it’s being used for the New Year’s Eve live webcast from Times Square in New York.

One of the biggest technical advances in electronic newsgathering has been the wide adoption of IP-based bonded cellular transmission for contribution feeds.

This “backpack” technology has made it easy to quickly transmit live and edited video from most places, and its quality and reliability have steadily improved as wireless carriers like Verizon and AT&T have expanded their networks and implemented Long-Term Evolution (LTE) technology, and vendors — including LiveU, TVU and Dejero — have refined their highly portable gear.

But bonded does have its limitations compared to traditional microwave. The biggest one being “contention issues” as more and more people — and more and more stations — use cellular networks to stream live video, thus clogging the bonded pipe.

Many rural markets still lack enough cellphone towers to make bonded transmission reliable. And some stations are finding bonded’s data costs onerous, with 40-50 GB of data costing around $500 per month, and many stations using twice that or more across multiple bonded units.

So top broadcast engineers and vendors are exploring ways to achieve the same flexibility and two-way connectivity that bonded cell affords within the Broadcast Auxiliary Spectrum (BAS), the microwave frequencies that stations have long been assigned for ENG use, by replacing their existing microwave systems with new technology.

“We’re using what we’ve got, and although it’s not brand new, it still works very well and we still use it in lots of markets,” says Rick Wheeler, Fox Television Stations Eastern region VP of engineering. “But I’m trying to think outside of the microwave box and get out of that end of the business. I still like the [BAS] frequencies, and obviously we’re licensed for those channels, but I’m looking for new modulation schemes to work within those channels.”


Wheeler and other top broadcast engineers have options. There are systems from established broadcast vendors that apply new transmission techniques to existing microwave infrastructure to achieve an IP-based workflow, such as Accelerated Media Technology’s ENGenesis and IMT/Vislink’s Newsnet.

These systems generally re-use existing microwave masts and towers, though new antennas and transmit/receive equipment need to be installed.

Another possibility is “mesh-networking” systems based on military radios reconfigured for broadcast use by companies such as Silvus Technologies and Persistent Systems, both relatively new players in newsgathering.

Instead of the point-to-point transmission methodology used by traditional microwave, mesh networks rely on multiple small radios that communicate among themselves to create a robust wireless network.

The radios can be mounted on cameras, in trucks or at fixed locations, and could be used in conjunction with existing bonded, microwave or satellite links.

The time is ripe for a BAS overhaul. Most of the existing microwave gear that stations use today is 10 years old or more and dates back to the 2 GHz Relocation Project, an FCC-mandated initiative under which the seven BAS channels in each market were shrunk from 17 MHz to 12 MHz each and moved to new frequency assignments to free up spectrum for Sprint Nextel and other wireless services.

Under the project, which ran from 2005 to 2010, stations switched to new digital microwave gear based on COFDM (DVB-T) modulation, with Sprint Nextel picking up the tab. Most of that gear is still working, but is nearing the end of its useful life, particularly when it is compared to the new bi-directional IP alternatives.

Here’s a look at the evolving IP-BAS technology based on projects involving some leading vendors in the space:

Accelerated Media Technologies

Broadcast truck vendor Accelerated Media Technologies (AMT) has been at the forefront of putting IP-based bonded cellular and Ka-band systems in news vehicles. Now it is trying to bring BAS into the IP age with its ENGenesis system, which remodulates the microwave spectrum to create a two-way LTE network with the ability to support up to 10 trucks on one 12 MHz ENG channel.

The ENGenesis approach, called “private LTE” by some, is already deployed at Graham Media’s WJXT Jacksonville, Fla., where it is being used by both live trucks and the station’s helicopter. AMT says it has six other stations under contract but their implementation has been delayed by tower delays relating to the broadcast repack.

ENGenesis is based on LTE radios originally built by defense giant General Dynamics for military applications, with Haivision providing MPEG-4 encoders and decoders. The system divides a typical microwave central receive site into three 120-degree sectors, using panel antennas and radios dedicated to each sector to transmit a bi-directional data stream that can include live video and audio feeds as well as voice over IP (VoIP), IFB (interruptible feedback), file transfers and other Internet traffic. Each sector delivers about 25 Mbps of throughput. Back at the station is a central receive server that can handle feeds from up to 30 radios.

An ENGenesis system can cost from $250,000 to $500,000, says Steve DeFala, AMT director of sales, with a system outfitted with three to four trucks, a couple of receive sites and a server running around $300,000. The signals can be received and transmitted via small omnidirectional antennas, for live-and-drive capability, and directional antennas mounted on a mast can also be used for long-distance transmissions or challenging signal environments.

One wrinkle, say broadcast engineers, is that stations with very high microwave antennas might need to relocate them for ENGenesis since 500 feet often works better for LTE than 2,000 feet. DeFala says that is incorrect, as ENGenesis has different requirements than LTE smartphones. He says that several stations in New York are exploring using ENGenesis off the One World Trade skyscraper.

WJXT started working with ENGenesis two years ago and the independent station now has it in five live trucks as well as its helicopter, with two towers outfitted for 360-degree coverage. One of the major attractions of ENGenesis for WJXT was the ability to remotely control the station’s helicopter from the studio over the bi-directional link, allowing it to save money by eliminating a camera operator aboard the chopper.

WJXT had some “growing pains” with ENGenesis in the first year, says WJXT Chief Engineer James Lowery, but worked with General Dynamics to sort out the bugs. The station has spent about $400,000 on the system, which Lowery says is far less than the estimated $900,000 to simply replace its existing microwave gear.

WJXT has a dozen TVU bonded-cell backpack units which it continues to use, but is getting ready to turn two of them in because of the performance of LTE. Since each backpack was using 80 to 90 GB of data per month, says Lowery, that will save the station about $2,000 per month or $24,000 per year. He plans to add two more sectors to the ENGenesis system next year.

“The reason why we do this, is so we can do more,” says Lowery. “We’ve got news 12 hours a day. Our morning newscast goes from 4:30 to 10 am. The LTE, it’s live for the five-and-a-half hour block; we have someone in the truck with the LTE unit running with a dashcam and the POV [point-of-view]. It doesn’t cost us any data, because we own the network, it’s a microwave link.”


Transmission gear vendor IMT/Vislink has created its own IP-centric system for the BAS spectrum called newsnet. It uses COFDM modulation (but a different flavor than DVB-T) in conjunction with time-slicing techniques TDD (Time Division Multiplexing) and TDMA (Time Division Multiple Access) to deliver encrypted, bi-directional communication across multiple radios.

Newsnet is designed to work with a station’s existing microwave infrastructure but requires new radios and modified antennas to create a system where mobile high-speed network “nodes,” such as news trucks, connect with a base station located at a microwave central receive site.

Newsnet uses four dual-polarized antennas at a microwave central receive site, which IMT/Vislink calls a “sector site,” and each looks at a 90 degree arc, or sector. The system delivers a maximum throughput of 70 Mbps for each sector site, says Lowell Beckner, newsnet product manager, with each of the four directional sectors getting 17.5 Mbps to share among multiple transceivers.

Newsnet uses a full 12 MHz BAS channel and tunes the frequencies (using both the plus-and-minus offsets) to create two 5 MHz channels per sector site.

Newsnet is able to re-use a truck’s existing microwave antenna, but Beckner says that IMT/Vislink will install a modified feedhorn that allows for full polarization (both the horizontal and vertical poles). For smaller vehicles like SUVs, newsnet also offers a low-profile MIMO antenna with internal array that’s about a foot tall and roughly the same diameter.

The newsnet nodes communicate with a central server back at the station, allowing other IP-based functions such as prompting and VoIP to be sent to the field and providing remote access to newsroom computer systems and media asset management systems.

Up to eight trucks can be connected to a sector at one time. The newsnet system manages bandwidth by delivering proxy-resolution from all of the trucks until a live HD feed is needed. A touchscreen interface at the station shows the trucks connected and the available bandwidth per sector.

In addition to providing “a complete ecosystem,” says Beckner, newsnet can be gradually rolled out within a market alongside existing DVB-T COFDM equipment. Newsnet leverages existing Newstream systems already deployed in the field. This enables an easy transition from DVB-T to newsnet both operationally and financially.  

If a station has two BAS channels assigned, one can be used with newsnet and the other with traditional ENG, or both systems could be used on one channel as long as only one was powered up at time. Beckner says that newsnet could also be used in the 7 GHz band as a transitional step.

Installing newsnet would cost about $180,000 for one truck, a sector site and a control server, not including tower work. Adding vehicles is cheaper because the station already has the server.

The first beta site for Newsnet is NBC’s New England Cable News in Boston, which is working on getting the system up and running with its helicopter. Keith Barbaria, NBC Boston VP of technology and operations, declined to be interviewed for this story, saying only that the project was still in its early stages.

No other station is actively testing Newsnet, though Beckner says that there has been fresh interest from several groups in the past month. KPRC, WJXT’s sister station in Jacksonville, Fla., is a longtime Vislink customer for traditional ENG and recently hosted IMT/Vislink for a Newsnet demonstration.

The demo was limited but successful, says Edgar Zavala, KPRC director of technology, with a KPRC news truck able to use a VoIP deskphone it borrowed from the station over the Newsnet network and two live HD feeds being sent concurrently in one sector.

Silvus Technologies

Los Angeles-based Silvus Technologies is an established provider of mesh-networking for government and military applications—customers include the Defense Advanced Research Projects Agency (DARPA), Army, Navy and Air Force—but a relatively new entrant in the broadcast space.

The company began marketing its technology for newsgathering at the 2015 NAB Show, showing a bi-directional radio system that worked with JVC’s ProHD streaming camcorders to deliver HD news feeds (JVC also has a bonded cellular solution called ProHD Bridge that uses the camcorder’s internal encoder).

In contrast to a point-to-point wireless transmission, mesh networks are based on wireless signals being relayed across multiple radios, each one serving as a a transceiver, to create a peer-to-peer mobile network without any centralized hub. The radios each act as “nodes” that automatically discover and connect to each other, and if one node goes down, communication across the network remains interrupted. This is called a Mobile Ad-Hoc Network (MANET).

Silvus’ StreamCaster radios, which use COFDM modulation, also employ MIMO — Multiple In, Multiple Out — technology, in which signals are both transmitted and received by multiple antennas in order to improve reception in difficult environments. Silvus calls the combination of these various technologies MN-MIMO (Mobile Networked MIMO).

Silvus’ radios first drew the attention of sports production specialists like CP Communications, which now uses them in the unlicensed 5 GHz band to provide wireless video links and camera control for Fox Sports’ golf coverage.

Silvus also did some demonstrations with local broadcasters at Super Bowl 50 in San Francisco in February 2016, and CBS O&O KOVR Sacramento, Calif., subsequently purchased the radios for use in the 5 GHz band.

Since then Silvus has incorporated support for the 2 GHz band, and they have been purchased by CNN for use in Atlanta, New York and Washington, and by Fox for several stations including WTXF Philadelphia, WAGA Atlanta, KDFW Dallas, WJBK Detroit and KTBC Austin, Texas. Other customers include ABC News, Cox’s WFTV Orlando, Fla., and Scripps’ WRTV Indianapolis.

Stations use the Silvus radios either to transmit live shots from a camera back to a news truck or to transmit directly to the studio when shooting nearby, says Mark Tommey, Silvus director of sales, broadcast. At WTXF in Philadelphia, for example, the systems generally operate in a four-to-five block range.

“They tend to use two wireless cams shooting into the mesh network, and we can put two video paths over the same network, just wtih different IP networking addresses,” says Tommey. “Those two video streams show up on two different decoders.”

In the case of CNN, the cable network has set up Silvus radios at several fixed locations in Washington such as the roof of the Hart Senate Office Building and at the Trump International Hotel, with fiber paths back to its Washington bureau. This provides wireless freedom for its camera operators within range of the mesh network, without having to worry about bonded-cell contention issues.

Silvus sells two versions of its StreamCaster; a smaller model with two omnidirectional antennas radio and up to 4 watts of output power that runs from $5,500 to $9,000, and a four-antenna model with up to 8 watts of power that runs from $9,000 to $15,000, depending on configuration.

Radios can have different power levels and be either single or dual-band, with 2 GHz BAS and 5 GHz in one radio. With the multiple antennas, Silvus employs a technique called “transmit beamforming” to achieve 3 to 6 dB of signal gain with the two-antenna radio and between 4 and 6 dB of gain with the four-antenna model.

Tommey says most stations have bought dual-band radios but many are currently using the 5 GHz band. One of the reasons why is that they can often get a wider “pedestal”, or usable slice of spectrum, in the unlicensed band. With a 20 MHz pedestal the Silvus radios can achieve up to 100 Mbps throughput, says Tommey, while the maximum they could achieve in an ENG channel would be 50 Mbps, with 20 Mbps being more the norm.

Fox stations generally try to operate their Silvus mesh networks in the BAS spectrum, where they work well, says Fox’s Wheeler. But some like WAGA use it in the unlicensed band.

“If you install it in an area where the mesh [network] isn’t mobile, it’s fixed, and you’ve got predictability, you greatly increase the likelihood of it working,” says Wheeler of unlicensed use.

But Wheeler still worries about interference issues in the unlicensed band, particularly as more stations adopt mesh networks. To aid further development of BAS-compliant mesh technology, he has actually loaned some frequencies in New York to another mesh-network vendor, Persistent Systems LLC, to help it develop a 2 GHz version of its MPU5 “smart radio” that is used by U.S. Special Forces troops and the FBI.

Persistent Systems

Like Silvus, New York-based Persistent has a long history as a government contractor but is relatively new to the broadcast market. It also uses MANET and MIMO technology in a mesh-network system based on small handheld radios. But the company says its proprietary Wave Relay algorithm provides superior performance by adapting to fluctuations in terrain and environment to deliver high-throughput, low-latency data transmissions at distances of up to 1 kilometer.

“Basically, we provide an Ethernet wire in the sky,” says James Ocon, Persistent Systems VP of business development. “We specialize in providing high data rates into hard-to-reach locations, where Wi-Fi or LTE is hard to operate.”

Ocon, a former VP of technology for Gray Television, is marketing mesh to broadcasters as a way to wirelessly deliver live video from the field back to an ENG van or production truck, particularly at big events when they previously would have relied on long cable runs.

The MPU5, which runs on the Android operating system and lists for around $11,000, has three omnidirectional antennas, a max output power of 6 watts and an integrated H.264 encoder that supports 1080p/30 or 720p/60 video.

Like Silvus’ radios, it also can also work easily with a streaming camera that has its own encoder through an Ethernet connection.

Ocon says that Persistent’s technology addresses “two pain points” for broadcasters: the rising data costs of using bonded cellular networks for short wireless hops and the labor and hassle involved with running cable to deliver news coverage from events like the Super Bowl.

Persistent’s MPU5 can already operate for broadcast applications on multiple frequencies including C-, L- and S-band, and is due to be used at next month’s Super Bowl for newsgathering applications. Persistent is now readying a version designed specifically for the 2 GHz spectrum, which it hopes to have commercially available this spring.

In addition to Fox, NBC and Sinclair have also helped test the new Persistent radio, which Wheeler says may work better than Silvus in challenging urban environments.

Sinclair Television Group CTO Del Parks confirms that the group has tested Persistent’s technology and said WJLA Washington is considering setting up a mesh network in a “heavily used area” on the BAS spectrum.

“That may be going from the camera all the way to the station, or maybe just to the truck,” says Parks, who adds that WJLA hopes to set it up “in a cooperative manner” with other stations and share costs.

Like any other new technology, the ROI will ultimately determine whether Sinclair uses mesh.

“From a cost perspective, you don’t want to spend $100,000 on a mesh network if you’re only going to use it three times a year,” says Parks. “But if you’re using it five times a week, and you don’t have to dedicate a live truck to it, that’s different.”

The BAS Endgame

Just as bonded cell works better in some markets than others, what new BAS technology stations adopt may depend greatly on the existing topography in their market. For example, Wheeler is impressed by the technical capabilities of the ENGenesis system but doesn’t think it’s well-suited to a market like New York, where WNYW currently has microwave receive sites on top of the Empire State Building and One World Trade.

Wheeler has no interest in contracting for lower antenna placements with other building owners in New York. In other markets LTE would be more feasible due to shorter towers, but Wheeler isn’t sure he would invest in swapping out existing antennas since he is trying to get out of leasing tower space in general.

He also says the ENGenesis gear is “big” and relatively expensive, and he wants to continue moving to smaller, lighter, less expensive equipment and smaller vehicles, a process that began with bonded cell.

“LTE is a great technology, and it’s got better coverage area than a mesh network does,” Wheeler says. “But the mesh network is a so much smaller footprint. I’m going to need more of it, but I don’t take up more square footage. I can outfit a vehicle with it, it’s much less expensive, and it’s the same workflow.”

It is possible that stations might adopt both mesh networking and LTE and use them together. WJXT is exploring using mesh-network systems from Silvus or Persistent as a wireless link from the camera to the truck, such as when shooting in an indoor location like a courthouse. Then it would use ENGenesis as the link back to the station.

WJXT succesfully tested such a scenario with the Silvus radios last month, using mesh in the unlicensed 5.2 GHz band to provide connectivity between a camera and an LTE-equipped truck or helicopter.

“The LTE devices aren’t going to go on the back of a camera,” Tommey says. “But getting that IP connectivity out to the camera is very attractive, especially as more and more camera manufacturers have encoders built in. Then you can look at camera control and all kinds of other stuff.”

Comments (1)

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Carmen Diaz says:

January 18, 2018 at 6:29 pm

Great article. It’s too bad the FCC has not responded to the July 25, 2016, Request for Declaratory Ruling filed by Vislink, Inc. That RDR asked the Commission to confirm the legality of two-way ENG under a TV station’s existing TV Pickup license. The architecture of two-way ENG does not quite meet the definitions for mobile TV Pickup stations or fixed link Inter City Relay stations. However, the architecture is identical to that approved for the narrow band Lower and Upper Data Return Link channels, so it is a logical extension of that architecture to the 12-MHz wide main 2 GHz ENG channels. So long as two-way LTE can be accomplished without interference to any adjacent-channel and nearby ENG receive-only sites, the FCC should not stand in the way of new and better technology. The recent entry of DoD into the 2 GHz TV BAS band may complicate the issue, although DoD has not only an obligation to not cause interference to existing Part 74 Subpart F TV BAS operations, but also to “not constrain the deployment and use” of Part 74 TV BAS (per the US92 footnote to the FCC Section 2.108 Table of Frequency Allocations, as adopted by the March 31, 2014, GN Docket 13-185 R&O).