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 August 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.

August 26, 1996 - Issue 39 Final

SATELLITE Cycle Sat to Convert to Digital Satellite Transmission (August 21)

In a news release issued today on PR Newswire, Cycle Sat said it had "completed the first two phases of their plan to begin delivering television spot commercials using MPEG-2 technology." Cycle Sat is using GI Communications Division MPEG-2 digital satellite encoders and GI DSR-4400 digital satellite receivers. The system is operating at 19.5 Mbs., over twice the rate commonly used for digital video distribution. The release noted that "In the future, this data rate will be the benchmark for transmission to the Cycle Sat network affiliate stations." At a "sneak preview" of the digital system at Cycle Sat's technical service center in Burbank, Tom Mikkelsen, VP and Chief Technology Officer, said "Our digital system is designed specifically for our broadcast network, and we utilize the best technologies available. Our package has received great approval by the people that use the system daily: the broadcasters and our clients; and they welcome our conversion to digital"

SATELLITE General Instrument and TCI Agree to Support Backyard Digital Dishes (August 21)

A Press Release from General Instrument announced that TCI's Head End in the Sky (HITS) has agreed in principe to support distribution of digital programming to the consumer "backyard dish" C-band market when HITS begins service the end of this year. Consumers equiped with GI's new MPEG- 2 receivers will be able to receive the over 80 video and 40 audio services TCI anticipates supplying. The release states: "Consumers with new digital C-band receivers will be able to access HITS programming primarily off G7. Utilizing 12 transponders on Ku-band satellite G7..." It did not explain how the C-band receivers would receive the Ku-band signals. Rich Fickie, Vice President of Marketing for HITS, was quoted as saying "We are encouraged by GI's demonstration of commitment to deploy new digital boxes in the consumer C-Band market, and believe this is a market programmers on HITS will be interested in. The HITS offering could provide consumers with a vast amount of digital content that will continue to grow". See the Press Release for more details.

TECHNOLOGY NCAR Tests New High-Tech Weather Radar (August 20)

The National Center for Atmospheric Research (NCAR) in Boulder Colorado issued a news release outlining the results of tests of their new experimental radar instruments, called S-Pols. The radars were able to distinquish between large, flat raindrops and round hailstones. Traditional Doppler radar is unable to do this. The release quoted NCAR scientist Jim Wilson: "Hail can fool Doppler radar into 'thinking' it's raining harder than it actually is, thereby introducing uncertainty into the issuance of flash flood warnings. S-Pol can more accurately measure the size and shape of raindrops. This helps us spot areas of heavy rainfall and predict the resulting runoff." While the release is not very technical, the system appears to be based on the use of two polarities for radar transmission and reception The experimental system is called "dual-polarimetric". The system uses a 28 foot aluminum dish mounted on a base of four seatainers, the same ones it can be shipped in. It was tested at Front Range Airport in Watkins, Colorado, the first town east of Denver on I-70.

August 19, 1996 - Issue 38 Final

HDTV - Public TV Engineers Study Impact of FCC DTV Allocations (August 19)

Current Online, the on-line edition of the bi-weekly newpaper on public broadcasting Current has an article adapted from its August 19th edition that describes some of the problems Public TV engineers see with the plan. While saying "the FCC has done an incredibly good job at dealing with a very complicated issue" Bruce Jacobs, engineering director at North Dakota's Prairie PTV, was concerned that the FCC's high replication figures may be "misleading". Harvey Arnold, associate director of North Carolina's PTV network, was concerned about loss of channels for translators. The article offers a very good overview of the FCC's channel and it worth reading.

FCC Offers Software for Automated Submission of Regulatory Fee Data (August 19)

In a Public Notice (pnmc6029.txt) the FCC announced it is offering a software program that can be used in place of manual submission of the detailed data. If the software is used, the data can be submitted on a disk along with the payment and a "Fee Remittance Advice" (Form 159). The software is available online from the FCC on the Fees Software Page. Regulatory fee schedules are available for Mass Media licensees (AM, FM, TV, LPTV, Broadcast Auxiliary), International Bureau (Satellite earth stations, shortwave broadcasters and other international carriers), Commercial Wireless and Cable TV.

INDUSTRY - Cox Broadcasting Signs Agreement with Harris for Digital TV transmitters (August 15)

Harris Corporation announced today that Cox Broadcasting had signed an agreement to purchase Harris digital television transmitters for its eleven owned and operated stations, including WSB in Atlanta and KTVU in Oakland/San Francisco.The Cox deal is the second major group digital transmitter purchase agreement snagged by Harris. In June the company signed an agreement with Capital Cities/ABC Inc. making it the supplier of digital TV transmitters for the group-owned stations. Harris has a digital TV transmitter operating at the first HDTV station on the air - WRAL-HD in Raleigh NC.

HDTV - FCC Releases 6th NPRM on Advanced TV (August 14)

Today the FCC released the much awaited Sixth Further Notice of Proposed Rule Making on Advanced Television Systems and Their Impact upon the Existing Television Broadcast Service. Copies of the NPRM in Adobe Acrobat PDF format and in the FCC's original WordPerfect format are available from a special web page. The Allocation Table extracted from Appendix B of the Notice is also available from the page as a Excel 4.0 spread sheet.

A convenient state by state listing of the FCC's proposed digital TV allocation plan is available from www.transmitter.com.

A quick glance at the allocations shows some potential problems, particularly along the Southern California coast where signals from San Diego TV stations are regularly received in Los Angeles and vice versa. The table has at least one DTV signal in Los Angeles on the same channel as full power NTSC station in San Diego that is received in parts of Los Angeles. I'll have more information on this in later issues.

SCIENCE - New Studies Show Stress May Cause Your Brain to Shrink (August 14)

Are the rapid changes in broadcasting and telecommunications increasing your stress level? If so, you may want to check out the release from Stanford University stating that "New studies of human brains show stress may shrink neurons". The Stanford release reported:

"In a review article in the Aug. 9 edition of the journal Science, biological sciences Professor Robert Sapolsky said that the work of several research groups shows links between long-term stressful life experiences, long-term exposure to hormones produced during stress, and shrinking of the part of the brain involved in some types of memory and learning."

HDTV - Dolby Laboratories Urges Quick Adoption of ATV Standard (August 13)

Dolby Laboratories issued a Press Release today summarizing its formal reply comments in the FCC's Fifth Further Notice of Proposed Rule Making (NPRM) on Advanced Television. The filing responded to comments filed by Digital Theater Systems (DTS) and Universal City Studios (MCA) that claimed Dolby's AC-3 digital audio compression system was obsolete. Dolby said that wasn't the case, replying that AC-3 is a "standard gaining increasing acceptance, with a range of evolutionary opportunities that still lie ahead". Dolby also said that DTS has not proven superiority nor is it an accepted standard in any consumer format. Dolby's filing also replied to other criticisms of the ATSC standard. Its reply comments included:

  • Allowing interlace transmission will not prevent a move towards progressive scan since the existing interlaced NTSC signals via VHS video tapes and conventional cable and terrestrial transmissions will be with us for many more years, and progressive displays will have to allow us to view these interlaced signals;
  • The transmission of non-square pixels does not prevent compatibility with computers since, where necessary, pixel shapes can be easily converted by a resampling/filtering process;
  • The 16:9 aspect ratio is a proper choice for a consumer display device as it is well suited to rendering all aspect ratios, from wide screen movies at 2.35:1 to conventional 4:3 television pictures and everything between. No image need be cropped horizontally or vertically to be fully displayed on a 16:9 screen. Abandonment of 16:9 would leave the U.S. isolated in the world with a unique aspect ratio, one that serves the purpose no better than 16:9;
  • The matter of downconversion of a transmitted wide screen picture to a 4:3 display needs attention from the ATSC Implementation Subgroup to control the final aspect ratio;
  • A layered resolution video coding system would reduce spectrum efficiency, and is not necessary for low cost receivers to become available;
  • The early success of the DBS industry does not imply that terrestrial DTV would not become another AM Stereo debacle if the Commission fails to mandate the ATSC DTV Standard. It may actually suggest the contrary, as there are already three different DBS systems operating in the US which are not interoperative, but competitive. This wastes valuable spectrum space, and should not be seen as the way to adopt digital television in the US.

Dolby has also placed its initial comments filed July 11th in the 5th NPRM on its web site. For the other side to these issues, see the Americans For Better Digital TV Press Release and related stories in the July RF Current.

August 12, 1996 - Issue 37 Final

SCIENCE - Martian Meteorite Mesmerizes Mainstream Media (August 12)

Last week you could switch on any TV newcast, even National Public Radio's esteemed news shows and hear stories about Martian life found on a meteorite. The stories often included clips from famous science fiction movies. President Clinton even got into the act. Behind the glitz, there is a substantial amount of real science. Perhaps more important, this discovery may once again lead the world to tackle another grand scientific/technological exploration such as those that put man on the moon, satellites in geostationary orbit and Europeans (and others) in the western hemisphere. Knowing that RF Current readers are looking for more than the popular press angle on science, I've collected a few links that will give you much deeper understanding of this latest discovery

SPECTRUM - Public Safety Wireless Advisory Comm. Draft Report Requests More Spectrum (August 9)

The FCC today released an Executive Summary of the Draft Report of the Public Safety Wireless Advisory Committee and requested comments on it. A copy of the full report is available on the Public Safety Wireless Advisory Committee site. Some of the observations and recommendations of the committee included:

These recommendations would have a significant affect on broadcasters (particularly translator and LPTV operations in the 60 - 69 channel range), TV remote news gathering in the 2 GHz. microwave band, and users of C band satellite receive systems in the 3.7 to 4.2 GHz. band. Comments are due by 5 PM EDT on Friday, August 16th.

FCC Increases Cost of Filing Fees Effective September 12 (August 8)

The FCC notified Congress that it will increase processing fees charged applicants, licensees and permittees on September 12, 1996. The increases are based on the Consumer Price Index - Urban cost of living increases. The FCC is legally permitted to adjust the fee schedule every two years. The News Release (nrmc6063.txt) announcing the increase said the "new Schedule of Charges will reflect the net change in the CPI-U of 21.5 percent, calculated from December 1989 through September 1995 in accordance with the Section 1.1115 of Part 1 of the Commission's rules.

FCC Limits Restrictions on Over-the-Air Reception Devices (August 8)

The FCC released the full text of its Report and Order, Memorandum Opinion and Order, and Further Notice of Proposed Rule Making on restrictions on antennas used for TV, DBS and MMDS reception. Earlier it issued a fact sheet on the Order which clearly outlines what the rules do and do not mean for people desiring to erect a satellite or MMDS dish or TV antenna.

In brief, the rules prohibit restrictions that:

  1. Unreasonably delay or prevent installation, maintenance or use
  2. Unreasonably increase the cost of installation, maintenance or use
  3. Preclude reception of an acceptable quality signal

Exceptions exist for health and safety reasons and for historical districts. "Reasonable" also may vary from community to community. If you have to screen your trash can or air conditioner, the Order doesn't consider a requirement to screen your satellite dish unreasonable. On the other hand, while communities can require dishes be located in the home owner's back yard, it appears they can't enforce this if you couldn't receive an acceptable quality signal from a back yard dish. Note this applies only to dishes under 39 inches in diameter, unless you live in Alaska. As far as TV antennas are concerned, local permits and safety regulations still apply. However, requirements for permits or fees for TV antenna masts under twelve feet will usually be considered unreasonable. These provisions only apply to privately owned property. The FCC requested comments on Rule Making for renters and condominium owners where the roof top is common property.

HDTV - WHD-TV Becomes 2nd HDTV Station on Air, 1st to Air Live Programming (August 7)

Yesterday WHD-TV, the Model HDTV Station funded equipment manufacturers and broadcasters, held the first public demonstration of the transmission and reception of live and taped HDTV using the Grand Alliance (ATSC) system proposed by the FCC. WHD-TV experimental license allows operation on channels 27, 30 and 34. Jim McKinney, Model HDTV Station Project Director was quoted as saying:

We are delighted that both the broadcast and reception of a Grand Alliance HDTV signal were successful and ahead of schedule. Both video and audio signals were broadcast as were data signals. Importantly, full high definition television pictures and digital audio signals were received, decoded and displayed as part of the first transmissions.
More details are available in a Press Release issued by the MSTV and CEMA. One interesting comment in the Press Release was that the WHD-TV HDTV demonstrations will include a taped segment of "Lawrence of Arabia," supplied by Sony Pictures Entertainment. In what appears to be an effort to quelch criticisms of the ATSC system by some in the computer and film industry, the released noted "The movie will be transmitted using progressive scan, and in its original aspect ratio."

WRAL-HD, in Raleigh NC holds the claim as the first HDTV station on the air. It too participated in Tuesday's demonstration. James F. Goodman, President and Chief Executive Officer of WRAL's parent company, Capitol Broadcasting Co., Inc., said today's demonstration of WRAL-HD is proof that private industry is ready to move forward with the proposed FCC standard for digital television. "HDTV," he said, "is critical to the future of free, over-the-air television in America. Consumers demand the best possible product and anyone who sees HDTV will agree this is the wave of the future. The Grand Alliance standard is a viable system and superior to anything offered abroad." WRAL-HD also took the opportunity to announce plans to tape three local events for broadcast on the station, starting Thursday (August 8). The production truck will be supplied by NHK. After testing signal strength in the Raleigh-Durham-Fayetteville area, the station plans to begin a regular, fixed program schedule in early fall.

WRAL-HD has put together an excellent collection of links and resources on HDTV on the WRAL HDTV web page announcing their license application. Be sure to check out the HDTV-Begins page which gives the story behind the first HDTV transmission on July 23rd. It is written from an engineering perspective and includes photos and comments from the participants, including CBS Vice President of Engineering Bob Seidel saying "Okay. You're beginning to see the first high definition carrier being transmitted. Okay we're up ten-o-six on the twenty third." Information about Tuesday's events is also available. Viewing these pages you really get a sense of history in the making.

August 5, 1996 - Issue 36 Final

FCC Updates Radio Frequency Radiation Hazard Guidelines (August 5)

The FCC today released details of its new guidelines for evaluating the environmental effects of radiofrequency emissions. The Office of Engineering and Technology outlined the new rules in an HTML formatted News Release that includes links to both WordPerfect and Adobe Acrobat copies of the entire rule making. A text version of the Order is available. The new guidelines shouldn't surprise readers who have been following the OET's efforts. In general, exposure limits in controlled environments is the same as before, although stations operating below 300 MHz. will also have to deal with additional types of exposure. In most cases, exposure limits in uncontrolled environments will be one fifth that permitted in controlled environments. Certain transmitters are categorically exempted, however, the guidelines and requirements for evaluation of hand-held devices will apply immediately. For other stations, the new RF guidelines will apply to applications filed after January 1, 1997. Look for a special report in next week's RF Current.

HDTV - FCC Proposes Policies for Initial DTV Allotments (July 30)

The FCC finally placed its July 25th News Release (nret6009.txt) titled "Commission Begins Final Step in the Implementation of Digital Television (DTV)" on-line. The Release adds little information to that reported in last week's RF Current. The report lists the proposed primary DTV allotment objectives as:

  1. Identify DTV allotments that fully accommodate all eligible broadcasters, i.e., provide a second channel for DTV service for all existing eligible NTSC broadcasters;
  2. Identify DTV allotments that replicate broadcasters' existing NTSC service areas; and
  3. Minimize unavoidable interference without preference to either NTSC or DTV service.
The report also noted the Commission's proposal to eventually locate all TV service within channels 7 to 51. The ideal of "early recovery" of spectrum used by TV channels 60 through 69 was mentioned. The Commission, however, did request comment on the Association for Maximum Service Television's suggestion that the entire existing TV spectrum be used during the transition phase, with spectrum recovery after the transition. The Commission wants to know if this approach might have less impact on LPTV and translator stations and result in less interference and improved service area replication.

FCC Releases On-Line Annual Report (July 30)

The FCC has placed its entire Annual Report on-line in hypertext format. The report details what the FCC as a whole and each Bureau in particular have accomplished in the past year. Hypertext links allow jumping direct to Notices of Proposed Rule making and other documents on the FCC's Web site. Check it out at http://www.fcc.gov/annual_report_95.html or read the News Release (nrmc6058.txt) for a more information. You will need the Adobe Acrobat reader to view the annual report. The free reader is available for downloading.

Other Issues Available:



1995 and 1996

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Last modified August 25, 1996 by Doug Lung dlung@transmitter.com
Copyright © 1996 H. Douglas Lung