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Stations Seek Fix for Part 15 Overkill

Broadcasters Get Stomped, Listeners Offended

Broadcasters Get Stomped, Listeners Offended

Some of the satellite radio plug-and-play devices flagged by the FCC for exceeding RF emission limits have been altered. But questions remain among broadcasters about how to prevent interference from these and other low-power wireless FM modulating add-on devices, including some models of iPods or MP3 players.

Broadcasters are concerned about what they say is growing interference from mobile devices as well as indoor and hand-held short-range FM modulators. Indeed, tests on several devices conducted for the NAB showed several exceeded Part 15 field strength limits and were substantially wider in bandwidth than the 200 kHz-wide FM channel (see sidebar.)
What Listeners Are SayingThese are excerpts of listener complaints to WYPR(FM) Baltimore received by the station in May and forwarded to the FCC. NAB released these comments to press with the personal identification removed. This text includes phrases that may be offensive to some readers.

“I listen to 88.1 (WYPR) on a regular basis, and within the past month interference has escalated. I know it’s satellite radio because I can hear Howard Stern and Robin! Sometimes it lasts only a minute or two when I’m near certain other cars. But when I’m on the highway it has gone on for 5 minutes or more. It’s not always possible to maneuver away from the offending vehicle.”

“The interference from Sirius while listening to your programming on 88.1 FM continues to increase during my commute along the I-95 corridor daily. In the last two days, I would offer to you that approximately 50 percent of your programming is overridden by the following words, phrases and language: b*tch, c*nt, sh*t, f*ck, topic of ‘golden showers,’ topic of ‘menstruation.'”

“It is so upsetting to drive along listening to an important news story or heart-felt humanitarian piece only to be interrupted by someone shouting out of my speaker: ‘…and her pussy smelled like diarrhea. Hahahaha.’ I have included this quote to offer ONE example of the type of grotesque dialogue I hear bursting in on what I have chosen to tune in to. … I no longer tune into WYPR when my children are in the car out of concern that they would witness the interruptions that occur at a daily minimum of six times during a 25-mile commute.
The issue involves technical matters not usually of interest to those outside of radio engineering circles. But it erupted into public awareness when listeners and broadcasters began complaining about uncensored, unwanted language being received by car radios from devices in nearby cars that were re-broadcasting satellite content onto the FM dial.

Essentially, some satellite radio-equipped cars have been turned into miniature rolling radio stations, causing interference to listeners in other cars who were tuned, typically, to the low end of the FM band.

Broadcasters want to know whether it is the devices, or the installation methods used, that cause interference to terrestrial stations.

To that end, NPR Labs planned to run tests on several satellite radio so-called FCC Part 15 devices for several weeks beginning in late June “to demonstrate the frequency of occurrence and investigate the instances of excessive field strengths from FM modulators,” said NPR Vice President and Chief Technology Officer Mike Starling, who is executive director of the lab.

Testing now

“Our issue is more over power and wide bandwidth,” said Starling. “There could be some [devices] running at legal power but running excessive radiation because of how they’re installed in a vehicle. We’re just now getting a sample of FM modulators into the lab to see if we could make some generalizations about what might be a power issue.”

NPR Labs briefed the North American Broadcasters Association about the test plan. NABA is made up of broadcasters in United States, Canada and Mexico and is a member of the International Telecommunications Union.

Starling said NPR sponsored a preliminary draft recommendation through the ITU and NABA that calls for an internationally recognized policy regarding FM modulated devices. The ITU has influence on manufacturers seeking to sell products globally.

The draft states: “NABA’s preliminary studies indicate that while emission limitations of FM modulators (250 uV/m at 3 meters) do not generally appear to be problematic to other receivers nearby in adjacent vehicles and rooms, some combination of installation errors and consumer misuse are becoming increasingly common …

“In mobile settings, switching devices are commonly provided to disconnect the external FM receiving aerial when the short-range FM modulator is in use. Improper connection or omission of these switches can result in direct radiation of the short-range FM modulator emission through the vehicle’s antenna system. This can result in audible detection or interference effects of the short-range modulator on nearby receivers for up to 100 meters [about 30 feet] or more.”

The modulator receives the satellite signal from the antenna, recognizes and decodes the information, converts it to an RF signal and wirelessly transmits that signal into the car stereo. Newer models are frequency agile, allowing consumers to select from anywhere on the FM band, from 87.9 to 107.9 MHz. They come with instructions to the consumer to choose a frequency that’s unused by stations in their market.

But older models can come pre-tuned to a low frequency or allow the consumer to select from only lower channels on the band, said Starling. These are the same frequencies noncom and religious stations use.

Instructions for the Audiovox Sirius model SRSIR-001, for example, available on the Sirius Web site, state that the “FM Switching Box,” typically used for the signal conversion, comes with a default setting to 88.5 MHz but can also be set to transmit on other frequencies, namely 88.1, 88.3, 88.7, 88.9, 89.1 and 89.3.

Bad consumer installs

The switch box, said Dave Wilson, director of technology and standards for the Consumer Electronics Association, usually is installed behind the car radio and has one output and two inputs: the car antenna and the audio output from a satellite tuner. If XM is turned on, for example, it will take the signal and modulate it onto an FM frequency; that signal is fed into the FM antenna input. When the FM receiver is turned off, a switch in the box disconnects the FM circuit and reconnects the car antenna.

Starling believes some consumers are installing the devices improperly, stripping a wire and taking the output of the satellite receiver directly to the antenna input of the car.

“The problem with that is, when you turn on the FM radio, the satellite signal is fed into the car, but it’s also sent back up the antenna and radiated out of the car antenna so the car is acting like a station,” said Wilson, who said this situation doesn’t mean the products themselves are not compliant with FCC’s Part 15 rules specifying a power limit of 250 microvolts per meter.

CEA seeks to address poor installations through a training program for installers.

Starling said once a car is turned into a low-power station, its signal can be heard on other cars for up to a quarter of a mile.

Tuning out

NPR has heard of complaints of interference from FM modulated devices to some member stations for the past couple of years, but complaints spiked this year as people began using devices given to them over the holidays, he said.

He cited WYPR(FM) in Baltimore and WDIY(FM) in Philadelphia as having the most problems with interference from FM modulated devices.

Those stations told Radio World in June that protests are still coming.

WYPR President/GM Anthony Brandon said, “The most vocal complaints are those who have picked up Howard Stern, and the sharp contrast to us is shocking,” he said. The station airs a non-commercial news/talk format.

Brandon said listeners in the fringe areas seem to be hit hardest. WYPR operates at 10 kW. A station with a stronger signal, such as WAMU’s 50 kW, may get fewer complaints, he believes. Brandon turned over approximately 60 complaints to the FCC.
NAB: Three-Quarters of Devices Exceeded Field-Strength LimitsNAB says many RF modulators on the market are not only overriding terrestrial signals but have the potential to interfere with HD Radio signals as well. In letters sent to the FCC and Senate Commerce Committee leadership, the trade group urged the commission to undertake “swift action” to solve the problem and “vigorously enforce” its Part 15 rules.

Most of the devices tested were not satellite radio RF modulators, but rather, MP3 or iPod-like devices.

NAB hired engineering firm Meintel, Sgrignoli & Wallace to test 17 FM modulated devices in light of recent complaints by listeners who say their terrestrial car radios are being interfered with by the devices.

“Thirteen of the 17 wireless devices (76 percent) were found to exceed the 48 dBuV/m limits of Part 15 operation. … Six devices were found to exceed the FCC field-strength limit by more than 2,000 percent,” NAB wrote in a letter to FCC Chairman Kevin Martin and Senate Commerce Committee Chairman Ted Stevens, R-Alaska and co-Chair Daniel Inouye, D-Hawaii.

In addition, NAB stated: “Many devices transmitted signals that were substantially wider in bandwidth than the 200 kHz-wide FM channel, resulting in potential interference not only to the signal in the channel to which the Part 15 device is tuned but to first- and second-adjacent-channel signals as well.”

The trade group says many modulators in the marketplace are violating FCC Part 15 rules and could interfere with new digital radios as well.
Neil Hever, program director of WDIY, said he’s afraid interference has caused considerable damage to his listenership, but he has no way to track it. “I suspect some listeners just gave up listening to us because of the constant irritation of interference.”

His hope is that Part 15 analog devices sold as vehicle add-ons eventually will disappear once drivers switch to “new, self-contained systems.”

Sources close to the commission would not confirm or deny the existence of an investigation of the satellite radio devices. They did say the agency monitors the certification process, which takes place at FCC-approved labs. Tens of thousands of such equipment certifications are issued every year. The reports are sent to the FCC for review so its engineers or lab personnel can review, for example, how the testing was done, what equipment was used and what measurements were taken, a source said.

Several models involved

XM first revealed in SEC filings this spring that the commission sent letters to some of its manufacturers asking for test data and emissions characteristics of certain FM modulated devices. Shipments to stores of several FM modulated devices stopped. Models affected included the XM RoadyXT, XM Delphi SkyFi2, Audiovox Xpress Model XMCK10 and the Sportscaster, made by AGT.

“We’ve been working closely with the FCC to ensure the products meet their requirements,” said spokesman Chance Patterson. A ferrite bead, also called a clip, was attached to the antenna wires of the first three products to reduce RF emissions. Inventory was modified at distribution centers and new product coming out of the factory includes the modification, he said.

Cost estimates for the ferrite add-on from several sources range from 25 cents for the manufacturer to $1.50 at retail.

The Sportscaster presents a different challenge to modify; the FM modulation is done in the body of the device rather than in the wiring. That fix remained under discussion, Patterson said.

XM was also working to modify the Delphi MyFi in June.

After the altered devices were given the go-ahead, the commission reserved 30 additional days to continue its review process, ask further questions and conduct more tests.

Sirius Satellite Radio said a couple of its radio manufacturing partners also heard from the FCC recently about FM modulated products exceeding commission emission limits; it said those products have been fixed.

In Sirius’ only public comments about the issue, David Frear, Sirius executive vice president and chief financial officer, said at a financial conference in May that the FCC had sent letters to two of its manufacturing partners “asking for their test data on FM modulated products and their emission characteristics.” That data was provided to Sirius and the commission, he said.

“Some of them did test outside of the allowable emissions,” Frear said.

Sirius “went into the plants and made the appropriate changes to production,” he said. “All of the products rolling off the line now are fully compliant with FCC standards.” He did not identify the manufacturers or the specific models.

Sirius did not respond to subsequent queries for comment. Starling said the company had been “especially responsive” to NPR in looking into the issue and answered questions about how the FM modulated products were made. NPR programming airs on Sirius.


One broadcast RF supplier likened the ferrite fix as an inexpensive “Band-Aid” so manufacturers wouldn’t have to redesign products.

No observers contacted for this article believe the satcasters would recall their products, because the problem is not deemed a safety issue.

While ferrite add-ons fix new products, they don’t address devices already in consumers’ hands.

The NPR testing will look at both XM and Sirius FM modulators. If it finds data “that leads us to specific conclusions, we’ll share that” with the FCC, NAB and manufacturers, Starling said.

The draft NABA recommendation states FM modulators should be frequency agile and have permanently attached male and female connectors to match the respective radio input and antenna connections to prevent “inadvertent reverse connection to the external antenna.” It also calls for tamper-proof antennas.

With Part 15 wireless devices proliferating, Starling suggests one possible solution: All such devices might be required to operate at 87.9 MHz. Though this is not currently a legal Part 15 frequency, some devices operate there now, he said.

Normally, radios don’t extend beyond the limits of the FM band at 88 MHz, although some do tune to 87.9 or 87.7, Wilson noted.

NAB President/CEO David Rehr also called for the FCC to look into the problem, noting the “unwelcome satellite programming that could clearly fall within the FCC’s definition of indecent material.” NAB’s timing coincided with the congressional vote to raise fines for broadcast indecency, leading XM to tag that maneuver a “desperate publicity stunt.”