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‘ZoneCasting’ Concept to Be Tested

Companies assess narrowly targeted broadcasting using FM booster network

PALM BEACH, Fla. — A proposed system called ZoneCasting would use a series of boosters to give FM radio stations the ability to divide their coverage areas into geographic zones and “geo-target” their advertising and programming. The system is being scrutinized by the FCC and others in the industry.

Geo-Broadcast Solutions says its ZoneCasting system uses GPS and mobile broadband technologies to slice up the FM signal but avoid interference via a single-frequency network made up of FM boosters.

Toallow the system to work, the company has asked the commission to modify its current rule that prohibits booster stations from originating programming. A booster operates on the same frequency as an FM station’s main channel and is used to improve signal within the station’s coverage contour.

The graphic shows a potential application of a ZoneCasting network architecture in Chicago. Zones show how coverage could be targeted to Chicago and the North Shore, the southwest suburbs and other areas. ‘FCC’ is the defined service contour. The map is a conceptual sample, not an actual case study.

Credit: Courtesy Harris

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The company and Harris are partnering on the first commercial test, which is expected to launch early next year at WRMF(FM) in Palm Beach, Fla.

Rich Redmond, vice president of product management and strategy, transmission systems for Harris Broadcast Communications, said WRMF will require experimental authority, which must be granted by the FCC.

Redmond said Harris believes the ZoneCasting initiative will open up advertising opportunities to many new companies. Geo-Broadcast Solutions has designated Harris as its supplier of choice for signal transmission equipment.

Limiting interference between a main channel signal and booster can be a challenge, broadcast engineers say. Geo-Broadcast Solutions said the purpose of the test at WRMF is to prove ZoneCasting will not cause excessive interference.

Dean Goodman, chief executive of WRMF owner Palm Beach Broadcasting, stated in a press release that localization of advertising to specific neighborhoods makes radio advertising both sensible and affordable for advertisers.

The company “is currently negotiating tower leases on behalf of WRMF,” said Geo-Broadcast Solutions CEO Peter Handy. Construction of the booster network is expected to begin by the end of the year, with completion by the end of the first quarter of 2013.

The WRMF test project is expected to include 22 FM boosters in an effort to create a zone to geo-target much of Broward County, Handy said, which represents a zone of 25-plus miles.

“Typically, an application would include a half-dozen boosters to cover a zone of eight to 10 miles,” according to Handy. “This is a very big and complicated network for WRMF. Using a series low-power transmitters and short sticks will provide for an almost seamless transition between zones and better signal strength on the fringes.”

Though it hasn’t done so yet, Handy is confident the commission will issue the experimental authorization needed to launch its ZoneCasting test.

Geo-Broadcast Solutions says it already tested ZoneCasting successfully at stations KNIV(FM) and KDUT(FM) in Salt Lake City, Utah, in March 2010, and at WWOJ(FM) in Sebring, Fla., in July 2011.

The company says the concept of geo-targeting content on FM radio will allow radio stations to make more money by selling advertising to new customers targeting specific geographical areas. In addition, the stations could serve the public interest by geo-targeting Amber Alerts and weather warnings.


Geo-Broadcast Solutions, based in Dallas, is an FM radio technology company that provides geographic targeting solutions, according to its website. Media Brokerage firm Star Media Group is part owner.

GeoBroadcast states that these zone maps are conceptual samples. ‘Actual zones in a real situation will depend on the broadcaster’s service contour, demographics, tower availability, terrain and propagation factors, and other considerations.’

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For the WRMF test project, Harris is deploying multiple corresponding Flexiva low-power FM transmitters within the network architecture, adding Intraplex SynchroCast simulcasting gear.

Both companies say the ZoneCasting system includes multiple transmission schemes for analog FM and HD Radio.

In its petition for rulemaking this year, Geo-Broadcast Solutions said it holds pending patents for the technology that enables the booster to avoid causing interference to the main channel and other boosters. A check of records with the United States Patent and Trademark Office indicates that the patents, the first of which was filed for in 2009, remained pending as of mid-October.

The FCC accepted public comments on the technology but had not taken further action on Geo-Broadcast Solutions’ request for rulemaking as of mid-October.

Several advertisers wrote the commission in favor of the proposal, claiming that radio advertising is cost prohibitive for many smaller businesses.

The ZoneCasting concept “helps put fairness back into radio broadcasting and opens up a critical advertising outlet for small businesses which have been effectively closed out of the medium for the better part of 10 years,” wrote Charles Moore, president of Dyna Wash, a prospective radio advertising client. Among the comments made during the filing period, none were opposed to the idea.

“We think our technology is very much in the public interest and we think the technology does not put anyone in harm’s way. There isn’t any new equipment the public needs to purchase to receive the programming,” Handy said. He is hopeful the FCC will issue a Notice of Proposed Rulemaking in 2013 “and eventually green light it.”

Summaries of Geo-Broadcast’s pending patents describe an “equipment system and methodologies for segmentation of listening area into sub-areas enabling delivery of localized auxiliary information” and “equipment, system and methodologies for time synchronization between multiple RF frequencies, RF power and antenna selection for boosters in segmented listening area delivering localized auxiliary information.”

According to the company, the system allows licensees to insert different hyper-local programming on each individual booster.

Several industry observers described ZoneCasting as an effort to marry the technology of the synchronous booster with marketing by increasing the commercial inventory that radio stations have to offer. That, coupled with the ability to target specific geographic areas within a primary facility’s 60 dBu contour with advertisements, is unique; however, doing so could raise serious interference issues, according to some observers.

An informal survey of numerous RF specialists and consulting engineers by RW found a variety of opinions on the eventual technical success of ZoneCasting.

Opinions vary

“At first glance, I’m a bit skeptical about such a system,” said Mario Hieb, a consulting engineer who has multi-FM translator management experience and is an occasional RW contributor.

“Boosters, which operate co-channel to the primary station, have been around for quite a while. Even in areas like Salt Lake City where there is significant terrain shielding between the valleys that make up the metro area, there are still interference zones where the primary and the booster have less than 15 dB of difference in signal.”

With synchronization, antenna selection and power control, one can somewhat control the interference zones, but they don’t go away entirely, according to Hieb, who added, “Because of enhanced error correction, HD Radio might work better where boosters are involved, but conventional FM would theoretically still suffer.”

Others queried about ZoneCasting see obstacles at the FCC and in the field before a successful commercial launch.

Jim Stanley, owner of Stanley Broadcast Engineering, said the commission’s stated mandate “is to protect broadcast licensees from receiving co-channel or adjacent-channel interference from other facilities, [but] since in this case it would be self-inflicted interference, they might grant such a request.”

However, limiting or eliminating interference within the geographical area where the primary and booster overlap would be challenging, Stanley said.

“Theoretically, where the primary and booster coverage contours are of equal amplitude, the analog FM stereo signal is unusable. This is caused when two equal amplitude signals of the same frequency are present in the IF of the receiver. Under this condition, the receiver discriminator cannot lock onto one signal and produces an unusable demodulated audio output,” Stanley wrote in an e-mail. “Propagation delay can be introduced into one or the other audio path to gain some control over the contour overlap regions.”

Stan Salek, senior engineer with Hammett & Edison Consulting Engineers, said analog compatibility would be a primary issue in running separate programming on the main and booster signals.

Hammett & Edison “has encountered two types of analog FM booster designs. The first is where the area to be served by the booster is severely terrain-shadowed from the main station transmitter. In that case, the booster almost operates as an independent station, anyway, so separating the audio programming at times would likely be unnoticed by the listener,” according to Salek.

“The other case is where the booster service area is not completely shielded from the main transmitter service area. In such cases, a great deal of engineering effort goes into synchronizing the carrier frequencies, stereo pilot frequencies and modulating signals of the main/booster transmitters,” Salek said. “So in reception areas where that synchronization is needed, separating the audio programs would seemingly result in an unusable situation until the programming is once again the same.”

In general, Salek concluded, it has been his experience that nearby co-channel analog FM facilities cannot just be implemented without the benefit of terrain shielding. Synchronization can help, but generally only in a relatively small area between the transmitters.

Meanwhile, Jeff Gehman, a principal with Kessler and Gehman Associates Inc., reviewed Geo-Broadcast’s proposed rulemaking and believes the system should work provided the company can convince the FCC to allow FM boosters to transmit programming different from the main station.

“Geo states that self-interference issues are minimized using an electronic synchronization technique they developed,” Gehman said.

Geo-Broadcast said Harris Intraplex Synchrocast technology allows for “synchronous delivery of content across the defined zones.”

Other observers believe the patents held by Geo-Broadcast hold the key to making the system work in total.

“It looks like these patents are the key since the Harris Intraplex Synchrocast system is decades old,” said Mark Fehlig, a consulting RF engineer.

A Harris spokesman said Synchrocast was introduced in the late 1990s and has migrated to IP in the last several years. “It’s also important to note that with the introduction of the Flexiva transmitter, Harris brought technology from its Digital TV and DAB digital radio experience, like integrated GPS, that isn’t available in other systems,” the Harris spokesman said.