RF CURRENT



Welcome to RF Current, a weekly electronic newsletter focusing on Broadcast technical and F.C.C. related issues. This newsletter is part of The RF Page @ www.transmitter.com, a web site devoted to TV Broadcast RF engineering. For more information see the What is... guide to the R.F. Page site.

Issues are dated each Monday, although recently I've needed an extra day or two to complete each issue. Articles may be posted earlier if time permits or if there is a major, breaking story.

<<< Back to October 4 - Issue 185

October 11, 1999 - Issue 186 Final Edition

SATELLITE - DirecTV Successfully Launches DIRECTV 1-R - capacity will enable local broadcast channels (Oct. 9)
DIRECTV 1-R was successfully launched at 20:28 PDT, October 9th on a Zenit rocket from the ocean-based Sea Launch platform. Visit the Boeing Sea Launch Web Site for photos of the launch. The satellite will eventually be located at 101 degrees West Longitude. Its extra capacity will provide the capacity needed to deliver local broadcast network channels to up to 20 of the nation's top television markets, once pending legislation is passed by the U.S. Congress.

The DIRECTV 1-R satellite is a Hughes HS601HP, with 16 high-power Ku-band transponders. DBS-1, now at 101 degrees W.L., will move to 110 degrees W.L. to serve as a backup satellite once DIRECTV 1-R is operational. DIRECTV expects DIRECTV 1-R to be offering servies by the end of this year. The FCC granted DIRECTV's request to allow the satellite to be tested at 82 degrees West Longitude for sixty-days, provided no harmful interference is caused to any lawfully operating radiocommunication system.

More information is available in the Hughes Press Release and the FCC Order and Authorization on DIRECTV's request for Special Temporary Authority to Operate the DBS-1R Direct Broadcast Satellite at 82 Degrees West Longitude for an Eight-Week Period.

WIRELESS - Adaptive Broadband Demos Prototype for MMDS Duplex Networking (Oct. 8)
Adaptive Broadband(tm) has demonstrated a working prototype of its AB-Access(tm) wireless data networking equipment operating in the 2.5 GHz MMDS band. The prototype works with either QPSK or 16QAM modulation, allowing data throughput up to 16.7 Mbps in one 6 MHz channel. Next year, units using 64QAM will support data rates up to 25 Mbps. AB-Access uses TDD/TDMA access technology, which allow flexible data rates in both upstream and downstream transmissions.

More information is available in the Adaptive Broadband Press Release.

DTV - RCA DTC100 DTV Set-top Box Now Shipping (Oct. 7)
RCA issued a press release Thursday titled RCA DTC100, The Industry's Most Affordable Digital Television Set-top Receiver, Now Shipping to Retail Customers. The press release, however, did not contain any information on the availability of the much awaited DTC100. The DTC100 set-top box, which will allow off-air reception of all 18 ATSC formats for display on a $2,499 multiformat digital high resolution monitor from RCA or on a standard analog TV set. The DTC100 set-top box, which also receives DirecTV digital satellite signals, has a suggested retail price of $649, as previously announced.

FCC Notice of Proposed Rule Making to Modify DTV Table of Allotments in Klamath Falls, OR (Oct. 5)
California Oregon Broadcasting, Inc. (COBI), licensee of KOTI, NTSC Channel 2 in Klamath Falls, Oregon has requested the substitution of DTV Channel 13 for its assigned DTV Channel 40. COBI said the channel 40 allocation would result in a 46 percent loss in population served, with a replication of only 54.5 percent. Use of DTV Channel 13 would improve the figure to 64.5 percent. The FCC determined COBI's application is acceptable under the 2 percent de-minimis rule and complies with principle community coverage requirements. The technical parameters of the modified allotment on Channel 13 would specify an effective radiated power of 45.3 kW at a height above average terrain of 671 meters.

Interested parties may file comments on or before November 26, 1999. Reply comments are due on or before December 13, 1999. Refer to the Notice of Proposed Rule Making (MM Docket 99-296) for details on the request and information on filing comments.

FCC Notice of Proposed Rule Making to Modify DTV Table of Allotments in Oklahoma City, OK (Oct. 5)
Ohio/Oklahoma Hearst-Argyle Television, Inc. (Hearst-Argyle), permittee of KOCO, NTSC Channel 5 in Oklahoma City, OK, has requested the substitution of DTV Channel 7 for its assigned DTV Channel 16. Hearst-Argyle states the use of channel 7 will allow it to provide service to 1,265,000 persons. Using channel 16, KOCO would provide service to only 1,146,000 persons. KOCO's analog station has 1,317,000 persons in its Grade B contour. The FCC has found this channel change would meet its requirements. The technical parameters of the modified allotment on Channel 7 would specify an effective radiated power of 45 kW at a height above average terrain of 446 meters.

Interested parties may file comments on or before November 26, 1999. Reply comments are due on or before December 13, 1999. Refer to the Notice of Proposed Rule Making (MM Docket 99-297) for details on the request and information on filing comments.

DTV - ATSC, CEMA and Others Continue to Support 8-VSB DTV Transmission Standard (Oct. 7)
The Consumer Electronics Manufacturers Association (CEMA) and the Advanced Television Systems Committee (ATSC) issued a joint Press Release reaffirming their support for the ATSC / 8-VSB DTV transmission standard. Gary Shapiro, president of the CEMA, commented, ""The ATSC DTV standard was carefully designed to meet the requirements of the American DTV broadcast market, and it does so brilliantly. Nearly three years after the 8-VSB system was approved, the DTV transition is well under way."

Robert Graves downplayed the results of Sinclair's 8-VSB Reception Tests, saying, ""The Sinclair demonstrations focused on one aspect of DTV reception - immunity to ghosts - to the exclusion of many other important parameters, Moreover, Sinclair's field experience has no bearing on the quality of the ATSC transmission standard itself, and ignores improved receivers on the near horizon designed to address the challenges of indoor reception." He rejected the idea that another transmission system should be considered, warning, "With the finish line clearly in sight, it would be foolhardy now to rethink the fundamental decisions surrounding the nation's digital television standard. Instead, we must continue to move forward, making improvements as we go, to bring the benefits of digital television to all Americans as quickly as possible."

FCC Releases Order On Reconsideration of Definition of Grade B TV Signals for SHVA Purposes (Oct. 7)
DIRECTV and EchoStar petitioned the FCC for reconsideration of its February 1, 1999 Report and Order that, among other things, defined methods for determining whether a household received "Grade B" service from a broadcast station for the purposes of the Satellite Home Viewers Act (SHVA).

The Order on Recondsideration denied EchoStar's petition to change the definition of Grade B and to include multipath (ghosting) in the service definition. The FCC said " raising the Grade B values to give a consumer a stronger television signal could actually exacerbate the problem of multipathing. As the signal strength increases, "noise" or "snow" in a television picture may be reduced, but the chance of ghosting increases. Moreover, the multipath "interference" created by the same signal is very difficult to measure objectively." The FCC indicated they may reconsider this, if a petitioner can offer "concrete solutions to the ghosting problem" that are "objective and verifiable." The FCC declined to revisit the confidence factor issue, as EchoStar had requested.

The FCC, however, did amend the rules to allow the use of a gain antenna with several elements or the half-wave diople originally endorsed. The revised rule, however, does say that an impedance match must be maintained at all frequencies. The FCC also relaxed the rule regarding the bandwidth of the signal level test instrument. Instruments with bandwidths from 200 kHz through 1 MHz will be allowed. The original rule required a bandwidth of at least 450 kHz.

See the Order on Reconsideration - Satellite Delivery of Network Signals to Unserved Households for Purposes of the Satellite Home Viewer Acts - Part 73 Definition and Measurement of Signals of Grade B Intensity (FCC 99-278) for the details and changed regulations.

TECHNOLOGY - Carbon Nanotubes May Be Ideal Emitter for Flat Panel Displays (October)
Flat screen television sets require emitters capable of creating stable high density electron emissions. Existing materials used in flat-panel displays use Spindt-type diamond and silicon emitters. A team of researchers from the University of North Carolina and Bell Laboratories/Lucent Technologies believe they have a better material - carbon nanotubes. RF Curent has reported on nanotube technology in previous issues. In this application, carbon nanotubes had the highest and most stable electron densities observed to date. The emission stability is a result of the nanotube's ship tip and its chemical robustness in a vacuum environment. Many conventional emitters degrade over time and become blunt. Some require special coatings to prevent interaction with the phosphors used in flat-panel displays.

More information on these developments is available in the Office of Naval Research October News Tips.

DTV - Motorola Releases Data Sheet and Specs for MCT5100 Integrated DTV Audio and Video Decoder (Oct. 6)
Motorola has released a data sheet and detailed specifications for the MCT5100 Integrated DTV Audio and Video Decoder announced last week. The MCT5100 takes an 8-VSB IF signal and outputs standard definition video and stereo audio. While the data sheet doesn't specifically state the unit is capable of decoding all 18 ATSC formats and displaying them on a standard definition display, the device is called a "'HDTV to NTSC" Converter Module. The module outputs RGB, composite (NTSC), S-Video or YUV/YPrPb signals. The module outputs stereo audio as well as a S/PDIF serial digital channel for Dolby Digital(tm). The module is fully enclosed in a metal can and has a 22 pin TV chassis interface.

More information is available in the MCT5100 Product Preview and the MCT5100 Data Sheet (Adobe Acrobat PDF).

OTHER Items of Interest

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Last modified October 17, 1999 by Doug Lung dlung@transmitter.com
Copyright 1999 H. Douglas Lung