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Issue: Aug. 15, 2008
White Space Devices Fail to Score at FedEx Field
Wireless microphone manufacturer Shure, Inc. said that white space devices failed to accurately detect wireless microphones during FCC tests conducted before a Redskins vs. Buffalo Bills pre-season game on Aug. 9 at FedEx field.
“The FCC’s tests of prototype white space devices at FedEx field prior to Saturday’s game between the Redskins and the Bills conclusively show that spectrum sensing white space devices will cause harmful interference to wireless microphones during live events,” said Mark Brunner, Shure’s senior director of public and industry relations.
Simply stated, the prototype devices were unable to consistently identify operating wireless microphones or distinguish occupied from unoccupied TV channels. More troubling, the devices failed to detect the presence of wireless microphones when switched on—an occurrence that takes place multiple times during any NFL game.
“Given the poor performance of these sensing devices, there is no reason to believe that the other proposed protections, such as beacons, will be any more capable of providing reliable and robust interference protection to wireless microphone transmissions,” Brunner said. “These tests reveal fundamental deficiencies of sensing devices—issues that cannot be pushed off with a promise to resolve these problems at some later time during certification testing.”
Brunner added that Shure appreciated that the FCC, NFL and ESPN acknowledged the importance of wireless mics at sporting events and agreed to the testing. He further called the use of wireless microphone technology as “critical” to players, referees and fans.
“If these sensing devices cannot be counted on, then the FCC must put them on the bench."
Scientific American covered the testing in their article Could Next-Gen Cell Phones Interrupt a Football Game?. The article disputes Brunner’s statement that the sensing devices failed. It quotes Kiran Challapali, a project leader at Philips Research saying, “Our prototype was tested for its ability to detect over-the-air ATSC (Advanced Television System Committee, or digital TV) and NTSC (National Television System Committee, or analog) signals, in addition to wireless microphones. We also successfully detected wireless microphones when switched on, in every instance."
You may recall from my earlier reports on the FCC white space device testing, that the Philips sensing unit was extremely sensitive, significantly limiting the number of channels available for use by the device.
The Scientific American article said the FCC would not reveal what it has found in its field tests.
Maybe Now's the Time for Licensed White Space, Aloha Partners Says
While much of the focus on white space devices has been on unlicensed devices, don’t rule out the possibility that licensed services may be given access to open channels after the DTV transition is completed. Aloha Partners, LP filed comments in the white space proceeding (ET Docket 04-186) outlining the benefits of allocating these TV channels for use by licensed rather than unlicensed devices.
In its comments, Aloha said licensed spectrum is utilized at least twice as much as unlicensed spectrum. To back up this claim, Aloha submitted results of a study comparing licensed spectrum utilization in the original cellular frequencies (806-902 MHz) versus the original unlicensed ISM frequencies (902-928 MHz). PCS licensed frequencies from 1710-1990 MHz were compared to unlicensed PC frequencies in the 2390-2560 MHz band. The study, conducted by the National Science Foundation, found that licensed spectrum was consistently used 2 to 10 times as much as unlicensed spectrum in the six locations studied. One of the six was the National Radio Astronomy observatory at Green Bank, W.Va., where none of the spectrum was used. The other locations were in Virginia near Washington D.C. and at Penn Station in New York City. While not included in the averages, spectrum utilization was also measured at the IIT Lab in Chicago.
Aloha’s comments included a page showing expected auction revenue from licensed white space use. If only co-channel stations are protected, the estimated revenue was $15 billion from Aloha Partners and $25 billion from Brattle Group. If both co-channel and adjacent channel stations, the revenue drops to $8 billion and $12 billion.
FCC Lifts Freeze on New 17/24 GHz BSS Applications
After allowing filing of applications to amend previously filed Broadcasting Satellite Service (BSS) applications in the 17/24 GHz bands, the FCC lifted the freeze on the filing of applications for new U.S. licensed space stations, or requests for market access by non-U.S licensed space stations in the 17/24 GHz BSS, effective Thursday, Aug. 14, 2008 at 10:00 am. Applications are being processed on a first-come, first-served licensing approach.
The Public Notice announcing the lifting of the freeze (DA 08-1887) states, “The Commission will grant a 17/24 GHz BSS application if the applicant is legally, technically and otherwise qualified, the proposed system complies with all applicable rules, regulations and policies, the proposed system is not technically incompatible with a previously-authorized space station or with a space station proposed in a previously-filed application, and the grant will serve the public interest, convenience, and necessity.”
Applications that don’t meet these criteria will be returned and the next application filed will be processed.
120 GHz Microwaves Provide Realtime HDTV at Olympics
Most broadcast microwaves operate in the 2, 7 and 13 GHz broadcast auxiliary service bands. Unfortunately, the bandwidth available in this part of the spectrum requires use of video compression for transmission of high-definition TV. The latency introduced by the compression can cause problems in live broadcasts. At the Beijing Olympics, Fuji Television Network Inc. and NTT Corp. are testing a possible solution for live feeds from the games. The two companies previously demonstrated simultaneous wireless transmission of multiple HDTV video channels without delay, using 120 GHz equipment. At this year’s Olympics, they are testing a compact, lower power 120 GHz transmitter that can be powered by batteries.
The equipment is intended for transmission of HDTV signals from special live feed locations at the Beijing Olympics to the International Broadcast Center over a range of about 1 km without using video compression. The system is supposed to provide live reports in HD from almost all of the Olympic Park area. The 120 GHz radios can handle data rates up to 11.1 Gbps, allowing transmission of up to six uncompressed HDTV signals.
EDN Writer Tries Off-Air DTV – Part Two
Electric Design News (EDN) senior technical editor Brian Dipert continued his tale of off-air TV reception in postings last Friday and this Thursday. Last week Jack Antonio, chief engineer at Reno, Nev. Station KTVN, along with his assistant, Eric Brown, visited Dipert, who was having trouble receiving the station, even though he was able to receive other stations on Slide Mountain, outside Reno.
It turned out the cable in his house was attenuating the high VHF DTV signals by 8 dB. After reviewing the specifications, the engineers confirmed that the Clearstream 2 antenna from Antennas Direct was a UHF-only antenna. Dipert asked Antennas Direct Founder and President Richard Schneider to explain the company’s claim of “consistent gain” through the entire DTV channel spectrum. Schneider responded that designing an antenna that would cover both bands without compromising UHF reception turned out to be harder than expected. The solution they came up with was to redesign the antenna balun to allow the feed line to act as a high-band VHF antenna. The ClearStream 5, a high-band VHF only antenna, is recommended for viewers in fringe areas with high-band VHF reception problems.
In my RF Technology column in the Sept. 3 issue of TV Technology magazine, I’ll look at spectrum usage after Feb. 17, 2009. One quarter of all U.S. TV stations will then be using VHF channels.
See Brian Dipert’s Thin-Air ATSC (And NTSC): An Engineer Visit and An Antenna Reposit for the full story. Also see Thin-Air ATSC (And NTSC): The De-Boost (or Over-Boost) Debacle describing Dipert’s experiences with TV preamplifiers.
Satellite Update
From FCC Report SAT-00546:
- Intelsat New Dawn Company has requested authority to construct, launch and operate a C/Ku/Extended C-band Fixed Satellite Service (FSS) satellite at 32.8 degrees east longitude (EL) using Earth-to-space frequencies in the 5850-6550 MHz and 14000-14500 MHz bands and space-to-Earth frequencies in the 3625-4200 MHz, 10950-11200 MHz, and 11450-11700 MHz bands. Intelsat requested a waiver of some technical requirements in the FCC rules.
- EchoStar requested special temporary authority (STA) to operate EchoStar 8 for 180 days in the 12.2-12.7 GHz and 17.3-17.8 GHz bands from 77 degrees west longitude (WL). The requested operations are pursuant to agreements between and among EchoStar, QuetzSat S. de R.L. de C.V. (QuetzSat), and SES Global Latin America, S.A.
From FCC Report SAT-00545.
- On Aug. 6 the FCC International Bureau’s Satellite Division approved an arrangement where SES Gibraltar will operate the AMC-21 satellite at 124.9 degrees WL under an authorization from the Gibraltar Regulatory Authority. When the transaction is completed, the FCC will add AMC-21 to the Permitted Space Station List for FSS and FSS Direct-to-Home service in the 11.7-12.2 GHz (space-to-Earth) and 14.0-14.5 GHz (Earth-to-space) frequency bands. Intelsat North America LLC’s request for modification of its authorization for C- and Ku-band Intelsat 602 allowing operation at 177.85 degrees EL using 3625-4200 MHz, 5850-6245 MHz, 10.95-11.2 GHz, 11.45-11.70 GHz and 14.00-14.50 GHz frequency bands was granted.
DTV Station Status
DTV Station Status per FCC CDBS – Aug. 14, 2008
LICENSED (LIC) 1249 (+1)
CONSTRUCTION PERMIT:(CP) 694 (+10)
CP Modification (CP MOD) 374 (+25)
STA (All variations - authorized) 1006 (-6)
STA (Modifications) 158 (-3)
APPLICATIONS (minus rule making and channel/service elections) 838 (-57)
Rule making - Digital channel changes
PENDING APPLICATIONS 76 (+3)
GRANTS 156 (-0-)
Final DTV Facilities Only (dtv_type = “POSTTRAN” or “BOTH”)
CONSTRUCTION PERMIT:(CP) 510 (+8)
CP Modification (CP MOD) 200 (+31)
APPLICATIONS (minus RM and elections) 597 (-63)
(Change from July 30, 2008 listing)
Note: These totals do not include digital class A TV, low power TV or TV translator entries. The total will be greater than the number of DTV stations as some stations have licenses, construction permits and applications on file. Some stations also have licenses, construction permits or applications for backup facilities (auxiliary broadcast). Subtracting the STA Modification number from the number in STA (All variations) will give a more accurate indication of the number of DTV stations operating under STA, although STA records sometimes remain in the CDBS long after the licensed facility is operational.
A spreadsheet (dtvdb.zip) showing all DTV entries (including digital LPTV and translator) in the FCC CDBS TV engineering database files as well as a spreadsheet (tvdb.zip) showing the entire TV engineering database (large file - over 2 MB) extracted from the CDBS will be available at www.xmtr.com/fcc/. The Aug. 14, 2008 spreadsheets are available now.
Your comments and story leads are always appreciated! Drop me a note at dlung@transmitter.com.
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