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.
This page contains stories from RF Current issues published in June 1996. Links referenced in the articles were current when published but by this time may have changed. If you find a bad link, try connecting to the home page of the publication or company and look for an archive of past articles.
This week the Committee on Commerce, Science, and Transportation resumed hearings examining the use and management of RF Spectrum. Thursday's session focused on spectrum for digital or high definition TV. People testifying included Robert Wright, NBC, Ray Rodriquez, Univision TV Network, William Sullivan, KPAX-TV in Missoula Montana, James Keelor, Cosmos Broadcasting in South Carolina, Craig Mundie, Microsoft, J. Peter Bingham, Philips Electronics, Robert Stearns, Compaq, and Rob Hummell from Dreamworks, representing the American Society of Cinematographers.
Information from the hearings was limited, however, Philips released information on the testimony of Dr. Bingham, a senior executive at Philips Electronics. He said that an ATV standard is "absolutely essential if the United States is ever to successfully transition to digital broadcast television". He also dimissed as "utterly cynical" the suggestions by some computer industry factions that the Grand Alliance system is not inoperatable with computers, pointing out the GA system is a combination of progessive and interlaced formats. He said "the genius of the Grand Alliance's 'Big Tent' is that no matter which format they choose, they're taken care of."
The Philips executive told the committee he predicted "If the Commission rejects the 'standard-certain' approach in favor of a patchwork-quilt strategy to digital broadcasting standards, American industry, the investment community and consumers will shy away from the investment needed to move this technology to its full fruition." He said "what could be one of America's crowning technological achievements of the 20th century would instead, over time, simply wither on the vine." Dr. Bingham also spoke out against proposals to auction spectrum for the digital TV transition, saying they "hang like a sword of Damocles over this digital revolution" and the increased costs would destroy the "entire economic basis for their decision to go digital."
NewsBytes reported Friday that NBC President and CEO had spoken in support of the overall objectives of Senator Pressler's Grand Spectrum Bill, but had "strong reservations" about several key proposals in the bill. NewsBytes subscribers can obtain the full text of the article, which appeared June 21.
Hearings will continue in closed session on Tuesday, June 25. If you have access to testimony made at the Spectrum hearings, please drop me a note at firstname.lastname@example.org. Note that I cannot use copyrighted material from other publications. I am willing to post copies of remarks (from official sources) on my site or link to them on your company's site.
HDTV Newsletter carried several stories related to the WRAL's HDTV station today. The Raleigh, N.C. experimental station, WRAL-HD, will use Channel 32. The transmitter will consist of a high power Harris SigmaCD transmitter using the CD-1 Digital TV exciter. The station will use a special version of Andrew Corporation's ALP series medium power UHF-TV slot antenna, fed with Andrew Heliax transmission line.
Please link to these stories on the HDTV Newsletter's Web site for more information:
At the time this issue was written, WRAL TV had not updated their HDTV project web page. Check it later in the week for updates.
Business Wire carried a story from Hauppauge Computer announcing a planned demonstration of the Hauppauge "WinCast/TV" board at PC Expo in New York. The board builds on existing Hauppauge products which show a "TV in a Window" on a PC screen by adding the ability to receive Intercast data. Intercast allows web pages to be received by a computer using data transmitted in the vertical interval of a conventional TV signal. Full details on Intercast are available in the organization's On Line Brochure. Norpak, a manufacturer of Vertical Blanking Interval (VBI) encoders often used for Intercast demonstrations has a web page that describes how VBI Internet distribution works.
Last week a small news item on PRNewswire from In Focus Systems (R) caught my attention. It was touting the "first SVGA Projector Featuring Texas Instrument's Digital Light Processing Technology", the "LitePro 620". The DMD (TM) holds promise of making high quality, high definition more affordable to consumers, although that isn't obvious from the quoted list price of $10,999 for the LitePro 620. Of course, the LitePro 620 also has extensive multimedia capability that may not be needed in mass market sets.
The T.I. Digital Micromirror Device (TM) or DMD (TM) is essentially an array of over 480,000 mirrors controlled by semiconductor optical switches. Visit Texas Instruments Web Page for an excellent tutorial describing "Digital Light Processing". An archive of press releases regarding previous TI demonstrations of the DLP subsystem technology and DMD prototypes is also available.
In remarks at the FCBA/Warren Publishing Wireless Communications Summit in Washington D.C. released today, Commissioner Susan Ness said:
"Unlike cellular and other subscriber-based services, free over-the-air broadcast services require a transmission standard if equipment is to be widely available at low prices. The standard also ensures that all Americans can have access to a full array of over-the-air broadcast programming. Consumers need to know that a TV set bought in Richmond will also work in Rochester and in Redwood City."However, she offered support for more flexibility in the future, saying "Once the digital television standard has had an opportunity to succeed, the FCC should consider relaxing its rules to permit other transmission systems which do not cause interference."
In the presentation, she also did not advocate a single standard for other over the air video distribution services such as DBS or "wireless cable". Full details are available in Ness' June 10th talk, released Friday, titled Spectrum Management Principles for the Twenty-First Century.
BusinessWire carried an announcement from Winstar that it had signed a licensing agreement with Source Media, Inc. to carry the "The Interactive Channel" on its new 38 GHz. systems. Source said the Interactive Channel "is capable of delivering Internet E-Mail and Web site programming." Winstar's release said it held 38 GHz. licenses in 41 of the top 45 U.S. MSAs. Information Week described the system in an article available on CMP's Techweb. The article pointed out that the system needed a clear line of sight path. It said Winstar claimed the service can provide 99.999% availability with a 10E-13 error rate. Initial speed will be 1.544 Mbps, eventually reaching 45 Mbps. Given broadcasters' experience with 38 GHz. analog links, it will be interesting to see how well the Winstar digital technology holds up in the real world under harsh weather conditions.
The FCC today issued a CORRECTION to its previous news release on its implementation of rules regarding silent broadcast stations pursuant to the Telecommunications Act of 1996. See the corrected report for details.
Today PR Newswire carried a short item indicating that General Instrument had agreed to acquire the MPEG-2/DVB product family of Compression Labs, Inc. Many digital broadcasters now require digital video compression systems comply with DVB standards. This acquistion is surprising in that GI is a DVB member and included DVB compliance as part of its Digicipher II specification. Dow Jones News Service reported GI paid 12.5 million dollars for CLI's Magnitude MPEG-2 line. Full details are now available in the June 10th Press Release from Compression Labs, Inc.
Harris Corporation, in a Press Release issued today, said Capital Cities/ABC Inc. signed an agreement making Harris Corporation its provider of Advanced Television transmitters. Under the agreement Capital Cities/ABC will purchase ATV transmitters for its ten owned and operated TV stations, including WABC, New York; KABC Los Angeles, WLS Chicago, WPVI Philadelphia, KGO San Francisco, KTRK Houston, WTVD Durham, KFSN Fresno, WTVG Toledo and WJRT Flint.
PanAmSat announced today that major performance tests are underway at its PAS-6 Atlantic Ocean Region satellite are underway at the manufacturer, Space Systems/Loral, in Palo Alto, California. The FS-1300 satellite will have 36 Ku-band transponders and is intended for Direct to Home (DTH) transmission of digitally compressed TV signals into Latin America. Full details are available in the Press Release from PanAmSat.
In the Report and Order on WT Docket No. 95-47 the "Commission adopted a Notice of Proposed Rule Making (Notice) proposing to allow Interactive Video and Data Service (IVDS) licensees to provide mobile service to subscribers on an ancillary basis." The NPRM continues:
We amend Part 95 of our rules to authorize mobile in addition to fixed operation for IVDS response transmitter units (RTUs) operated with an effective radiated power (ERP) of 100 milliwatts or less. We also eliminate, for such low-power mobile RTUs, the requirement that such units utilize automatic power control. In addition to authorizing such mobile IVDS operations, we eliminate the IVDS duty cycle requirement for operations outside of TV channel 13 Grade B contours. The power restriction on mobile devices and duty cycle limitation in TV channel 13 markets will help ensure noninterference with respect to TV channel 13 while permitting IVDS licensees to provide a variety of new applications. Finally, we permit communication between cell transmitter stations (CTSs) on a primary basis. Together, these amendments provide additional flexibility for IVDS licensees to meet the communications needs of the public, which the record indicates may include commercial data distribution and inventory monitoring services, without increasing the likelihood of objectionable interference to other licensees.
While the possibility of interference to Channel 13 TV signals is admitted, the R&O pointed out that the 100 mW power limitation should provide sufficient protection. Of particular interest to broadcasters is the the Commission's statement that the "NAB's contention that IVDS should be developed primarily as an interactive service for use in conjunction with the broadcast industry is misplaced." Instead, the FCC takes a broad view of IVDS as a two way service "for exchanges with other services providing video, voice and data." A quick overview of the R&O is available in FCC NEWSReport No. DC 96-46
In two recent speeches FCC Chairman Reed Hundt suggested "a five percent "set aside" for educational television and free time for candidates on the new digital spectrum." The five percent is based on programming time, not data rate or spectrum. Full details are available in Hundt's May 23 speech at the National Press Club in Washington DC and in his June 6th talk at Museum of Television and Radio in New York.
In the last speech Hundt also noted that Bill Gates and the Business Software Coalition were in his office "expressing concern that a Commission misstep could have a significant negative impact on our country's economic growth. They don't know why a progressive-only, computer-friendly standard shouldn't be preferred, if we are to pick a standard." He invited comments on recently released Fifth Further Notice of Proposed Rule Making in MM Docket No. 87-268 on Advanced TV, asking "Why is it in the public interest to adopt rules freezing the current state of technology?"
In the March 1996 RF Current I reported on the NASA and Italian Space Agency Tethered Satellite Experiment. Last week NASA issued a Press Release 96-112 on the investigation of the failure of the tether. The report noted the tether broke as a result of "arcing and burning of the tether, leading to a tensile failure after a significant portion of the tether had burned away...". It noted that a breach in the layer of insulation surrounding the conductor allowed current to arc from the wire in the tether to a nearby electrical ground. During the experiment the tether system was generating 3,500 volts of DC at up to 500 milliamps.
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Last modified June 23, 1996 by Doug Lung email@example.com
Copyright © 1996 H. Douglas Lung