WHEAT:NEWS Volume 6, No. 5

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Summer has hit HARD here in the southern and middle Atlantic states, and we hope you're ready. Now's the time to recheck those transmitter building air filters and air handlers, and make sure your plant is prepared for the summer's baking heat.

This month in WHEAT:NEWS we'll have a feature on IP Microwave STLs, courtesy of our friends at DoubleRadius. We'll have the latest findings in the first on-air use of Belar's ADC algorithm for the elimination of diversity delays in HD/FM broadcasting. We'll visit Leighton's studios in St. Cloud, Minnesota, and we'll find out what "ACI" means and what it's all about.

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Life on the EDGE: STL via IP Microwave

WheatstoneIP STL Splash 300Any wireless IP microwave system will work as an STL, just as any camera (or phone) can take a picture. But as to how far and how robust, and for how much, that’s when the picture starts to get a little fuzzy.

There’s licensed versus unlicensed systems. Part 101 versus Part 15. Full duplex or half. Matters of throughput, range, delay and buffering, and where to install it and with what – it’s all-important in the wireless IP world. And certainly there’s cost, which can start at $500 for a basic unlicensed-frequency wireless IP system complete with radios and dishes and run up to $30,000 for a licensed-frequency system, depending on how far, how fast, and how reliable you need that link to be.

Systems vary, but they all have a few basic advantages.

High-speed Bidirectional IP Data Throughput

When you put up an IP link from the studio to the transmitter, your transmitter site immediately becomes part of your Ethernet network. Audio from a WheatNet-IP audio network I/O BLADE or EDGE unit connects directly into the IP wireless radio through RJ-45 connectors, and because it’s all IP, that means you can carry audio, video, voice-over-IP, and data of all kinds. Back and forth. Both ways. If you have video surveillance at your tower site, you can carry that data back. If you have a Burk or other transmitter remote control system, you can carry that data back. And, if your transmitter is remotely located with spotty or no cellphone coverage, you can put VoIP out there and carry that back and forth over wireless IP. Your remote tower site is now part of your network, even though it’s miles down the road.

Wireless IP systems can go some distance, too. “Our longest shot on wireless IP microwave is 55 miles,” says Jeff Holdenrid, who specializes in wireless IP for broadcast and other emerging markets for DoubleRadius engineering firm. Jeff has installed dozens of wireless IP microwave systems with our WheatNet-IP audio network in the past five years, most averaging in the 20 to 25 mile range.

The make or break rule is, as always, line of sight.

As for throughput, IP microwave has plenty of that, too. For example, a WheatNet-IP audio IP-88D BLADE into an IP wireless radio can run 8 stereo channels across a wireless IP link and still have enough bandwidth left over for all those things we just talked about: video surveillance, VoIP, remote control and other periphery functions.


Edge-Flowchart 2560Licensed Versus Unlicensed

Your choices are generally 5.8 GHz unlicensed wireless IP systems or licensed wireless IP systems in the Part 101 band, usually 6 GHz or 11 GHz (18 GHz and 23 GHz under Part 101 aren’t all that practical for ranges beyond one to two miles). Licensed systems are generally full duplex, whereas unlicensed wireless IP systems are almost always half-duplex.

The former has the obvious benefit of a licensed frequency as protection against someone using and interfering with that frequency for their purposes, but the latter can be useful, as well.

IP wireless systems operating on the unlicensed band often make a good option as an affordable backup STL. They’re also priced low enough to bring VoIP communications to transmitter sites that have limited or expensive cell coverage. “A lot of broadcasters are paying $600 or $1000 a month for their Internet connection to the transmitter site. Other than a tower climb to install the wireless, their return on investment is two to three months compared to paying for a leased line from their provider,” explains Jeff.

One critical difference between unlicensed and licensed wireless IP systems is how the two handle latency. According to Jeff, latency on an unlicensed system can jump from 2 milliseconds up to 12 or 20 milliseconds depending on interference or something as simple as changes in weather patterns. Comparatively, IP wireless radios operating on a licensed frequency have a consistent, lower latency, typically around 100 microseconds.

But there are plenty of uses for unlicensed 5.8 GHz IP wireless systems, especially now that Wheatstone introduced in April a special network unit, the Network EDGE, which has more data buffering built into it in order to handle the latency swings typical of unlicensed wireless IP radios. The EDGE provides the necessary delay as a buffer to any latency shifts that come across the link, which acts as a interface between the WheatNet-IP audio network and the IP radio.

“Unlicensed IP has taken off because for 1,000 dollars you can get a system, and now that the EDGE can hold the clock time consistently, we’ll probably see more applications for these,” says Jeff.

Unlicensed: Distance and Throughput

Although unlicensed systems can go far (the 55-miler that Jeff mentioned earlier is an unlicensed wireless IP microwave), generally you’re going to be trading off throughput for distance. “The biggest unlicensed radios --- like the Airfiber by Ubiquiti – have a shorter range and you can pull 700 megs out of them in a perfect world scenario (half-duplex),” says Jeff. But with licensed, he adds, “We can stack up greater than 2.5 gig.”

If you’re considering an unlicensed system, features like interference mitigation will be important. “In the 5.8 world, there’s the signal to interference ratio – how much noise it can take before the link drops. Some of these products have interference mitigation, where they see the frequencies all the time, so if someone puts something up on your band, it jumps to the best frequency it can perform on. If you’re considering unlicensed, that’s going to be a big product differentiator,” says Jeff.

Whether you decide on licensed or unlicensed, you’ll need IP wireless radios and microwave dishes on each end of the STL, and a good surge protector. For more information on WheatNet-IP and IP microwave STLs, contact your Wheat sales team.

Next month in Wheat News, we’ll explore licensed IP microwave systems.

Jeff Holdenrid is a senior sales engineer with DoubleRadius. He can be reached at 866-891-3602 X185 or by email at This email address is being protected from spambots. You need JavaScript enabled to view it..

Time to Align: Belar and Wheatstone

BelarStory2 2000We went live in New York and Detroit with a Wheat processor and Belar’s ADC algorithm to determine the success of HD radio and analog signal alignment in blended areas.

Tests so far look promising, indicating a consistent and seamless HD blend to analog whenever HD Radio coverage is less than robust.

"We've had the system on since the beginning of May and the delay between the analog and HD has been within one sample. It was pretty close before, but now it's spot on,” said engineer Brian Kerklan with WMUZ-FM in Detroit, a market chosen for its ties with the auto industry. Belar’s FMHD-1 continuously measures FM/HD time alignment and transmits closed-loop diversity delay corrections back to the Wheatstone on-air processor via our ACI interface. (See related article in this edition of Wheat:News: ACI: It’s Wheatstone’s DNA Needle and Thread).

Initial Findings

Belar's FMHD-1 has a +/- 375mS correction window, so if alignment is within that error band, it can measure it and tell the processor what correction to make. Our processors can adjust over their entire diversity delay range. ”Because the correction scheme is 'closed loop', there are normally no large jumps in delay as correction is applied. With a closed loop system, delay correction is typically on the order of a few samples at most, once the target delay value is met. If I were to go and purposely enter a 300ms offset at the processor, the Belar would see it, order the processor back to the correct value, and then keep it there - probably in one or two or perhaps three correction jumps from what I have observed,” explained Jeff Keith, Wheatstone’s Senior Product Development Engineer for the Vorsis line.

Also being field tested is a new Wheatstone “ramp delay correction” feature that if the time offset error is larger than "x", the correction ramps the delay towards zero offset in user-definable small increments steps over "x" time; both variables are user-definable.

These new developments will eliminate the need for yet another box in the air chain to correct for diversity delay errors between the HD digital and FM analog signals. Wheatstone processors AirAuraX3, FM-531HD, VP-8ip and FM-55 support the automatic diversity delay correction.

ACI: It’s Wheatstone’s DNA Needle and Thread

ACI STORY_1000We have built into all of our audio processors a control protocol we call ACI, for Automation Control Interface. ACI is how Belar’s FMHD-1 with new ADC algorithm tells our audio processors what corrections need to be made for a consistent and seamless HD blend to analog whenever HD Radio coverage is less than robust.

ACI operates over the locally connected network via TCP/IP and can touch any parameter on the processor, whether it's a setting for the diversity delay, recalling a preset, changing input sources, modifying output levels, or even lowering just the AGC band three threshold by 1.62dB during some externally triggered event. Most of the program automation systems can also talk ACI, as can our console surfaces, so ACI brings new possibilities to our audio processors as well as WheatNet-IP system.

From St. Cloud to Grand Forks, Leighton’s Dream Studios

There’s a lot of that going on here, from the usual satellite relays to the calls on-hold and lobby P.A. systems that are part of the WheatNet-IP system. (They put the phone system and lobby speakers on WheatNet-IP, and the NexGen automatically changes the station every hour for waiting guests. Cool.) They’ve even engineered the WheatNet-IP to unlock the doors in the morning. “We have programed soft keys on the consoles to unlock doors for early morning guests through the I/Os on the BLADEs,” said Tony Abfalter, DOE for Leighton.

Video: Audio over IP Control Applications

andyframe 300In this video, Wheatstone Vice President Andy Calvanese talks about the unique control aspects of our WheatNet-IP intelligent network. He discusses how the inclusion of three key components in the network are critical to making it adaptable to virtually every production and live broadcast application.



  • RP Broadcasting (Bemidji, MN) purchased an L-12 control surface
  • Bustos Media (Portland, OR) purchased an IP-12 digital console and M4-IP four-channel mic processor BLADE.
  • CHIN-FM (Ottawa, ON) purchased an IP-16 digital console and IP-12 digital console.
  • CBC (Edmonton, AB) purchased a split E-6 control surface for an existing WheatNet-IP audio network.
  • Badlands Radio Network (Sioux Falls, SD) purchased an LX-24 control surface.
  • KEXP-FM (Seattle, WA) purchased an L-8 control surface and an LX-24 control surface.
  • Jackson State University (Mississippi) purchased an E-1 control surface.
  • Entravision (Los Angeles, CA) purchased an L-12 control surface.
  • Beasley Broadcast (Fayetteville, NC) purchased an E-1 control surface.
  • Mexicast purchased an IP-12 digital audio console.
  • iHeartMedia (Myrtle Beach, SC) purchased an IP-12 digital console.
  • Goodwill Industries (Dayton, OH) purchased an IP-12 digital console through AVI Systems.
  • Signal Media (Little Rock, AR) purchased an IP-12 digital console.
  • Office of Cable Television (Washington, D.C.) purchased an E-1 control surface with WheatNet-IP audio networking through CEI.
  • College of Staten Island’s WSIA-FM (New York) purchased three LX-24 control surfaces and WheatNet-IP audio network.
  • WITI-TV (Milwaukee, WI) purchased two E-6 control surfaces.
  • Diversified Systems (DSI) (Washington, DC) purchased a Series Four TV audio console for Xinhua News.

Audioarts Engineering

  • WRBE-FM (Lucedale, MS) purchased an Air-4 console.
  • WVLI-FM (Kankakee, IL) purchased an R-55e audio console.
  • KNEI-FM (Waukon, IA) purchased an Air-1 console.
  • Agile Broadcast (Australia) purchased an Air-4 console and WheatNet-IP audio network BLADEs.
  • Apex Broadcasting (Fort Walton Beach, FL) purchased an R-55e console.
  • WVXE-LP/Calvary Chapel (Orange Park, FL) purchased an Air-4 console.
  • KXKZ-FM (Ruston, LA) purchased an R-55e console.
  • Crouse Kimzey (Grand Prairie, TX) purchased a D-76 console.
  • Northwest Missouri State University (Maryville, MO) purchased an R-55e console.
  • SAVE DIFFUSION purchased an Air-1 console, LX-24 control surface and M4-IP four channel mic processors.
  • Sun Prairie Media Center (Sun Prairie, WI) purchased an Air-4 console.
  • New Haven Independent (Connecticut) purchased an Air-4 console.
  • WRFD-AM (Columbus, OH) purchased an R-55e console.

Wheatstone Audio Processing

  • KKDA/KRNB-FM (Grand Prairie, TX) purchased an FM-55 audio processor.
  • CICX-FM (Orillia, ON) purchased an FM-55 audio processor.
  • CHIN-FM (Ottawa, ON) purchased an M4-IP four channel mic processor BLADE.
  • KEXP-FM (Seattle, WA) purchased an M4-IP four channel mic processor BLADE and FM-531HD audio processor.
  • Beasley (Philadelphia, PA) purchased several M4-IP four channel mic processor BLADEs.
  • Ocala Broadcasting (Florida) purchased an M2 dual channel mic processor.
  • Media Engineering (Switzerland) purchased several M4-IP four channel mic processor BLADEs.
  • CBS (Houston, TX) purchased an M1 mic processor and M4-IP four channel mic processor BLADE.