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 February 1997. 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. If you find a changed link, I'd appreciate it if you'd let me know by dropping me a note indicating the new location at firstname.lastname@example.org.
Venture outside about an hour and half before dawn and look to the east-northeast, about 20 degrees above the horizon. You should be able to see what looks like a fuzzy star. It is comet Hale-Bopp. You may see a tail extending above the comet if light pollution isn't too intense. Binoculars should make it visible even with light pollution. The comet should grow brighter through March, reaching a peak late in the month or in early April.
NASA has collected together the best links to Hale-Bopp information, including links to recent (often within the last 24 hours) photos of the comet. Check out the Comet Hale-Bopp Home Page. Viewing information is available from Sky and Telescope's Comet Page. I also recommend the NASA page Information on Comet Hale-Bopp for the Non-Astronomer
Wednesday the FCC released a Report and Order that established a new Wireless Communications Service, Part 27, using frequencies at 2305 to 2320 MHz. and 2345 to 2360 MHz. The rules offer a maximum amount of flexibility - a WCS licensee may offer services including data and wireless local loop services, wireless Internet access and other one way or two way services that meet the technical requirements of Part 27. Licenses won in an auction would be granted for ten years and licensees would have to provide "substantial service" within their license term.
One major constraint on WCS applications is the need to protect other allocations, either in the same band or on adjacent frequencies. The FCC felt that the protection criteria required to protect satellite Direct Audio Broadcast would preclude the use of the frequencies for mobile communications. The 2310 to 2360 MHz. spectrum is allocated to broadcast-satellite service and fixed and mobile radiolocation services on a primary basis. The Amateur Radio Service is also allocated frequencies, on a secondary basis, in both WCS bands. The FCC decided continue to allow amateurs and aeronautical telemetry to continue to use the bands, provided they do not interfere with WCS licensees.
Of interest to TV broadcasters, the Report and Order said that the Commission found little interest in these bands from public safety radio users. It said that the comments of the Association of Public-Safety Communications Officials (APCO) requested "that the Commission move forward to allocate at least 24 MHz of spectrum from UHF channels 60-69 to public safety and suggests that the Commission recommend to Congress that it take action to permit a portion of the proceeds from the 2.3 GHz auction to be targeted for funding public safety communications systems in other bands." The FCC response was
It is our belief that public safety agencies would benefit greatly from such action. We note that legislation recently introduced by Senator John McCain would provide for a portion of the revenues raised from an auction of spectrum currently used by television broadcast stations operating on channels 60-69 to be earmarked for "funding State and local law enforcement and public safety agencies' mission-related radio communications capabilities." We believe that legislative approaches such as that taken in the McCain bill would substantially aid public safety agencies in their communications needs and thereby improve the safety of all Americans.
The FCC also stated
In addition, we note that several commenters, including APCO and Motorola, reiterated the public safety community's need for 24 MHz of spectrum at UHF channels 60-69. We believe that their proposal has merit and plan to give it serious consideration in our Digital Television proceeding. We note that legislation recently introduced by Senator McCain would direct the Commission to allocate 24 MHz of the channel 60-69 spectrum to public safety use, and that the Administration's 1998 budget also supports such a reallocation.
A short summary of the Report and Order, which does not include the specific references to allocation of spectrum from TV channels 60-69 for public safety use, is available in a News Release. More information and links to the McCain bill are available in last week's RF Current, below.
In a bill introduced February 4, 1997, Senator McCain introduced a bill, S.255, to " To amend the Communications Act of 1934 to provide for the reallocation and auction of a portion of the electromagnetic spectrum to enhance law enforcement and public safety telecommunications, and for other purposes." The bill states that within 30 days after it is enacted, the Commission "shall allocate and assign 24 megahertz of electromagnetic spectrum to law enforcement and public safety use."
The spectrum is taken from the TV channels between 746 and 806 MHz. The bill also states that "Within 1 year after the date of enactment of that Act, the Commission shall allocate 36 megahertz of electromagnetic spectrum between 746 and 806 megahertz for commercial uses." The bill also provides that up to $750,000,000 of auction revenue can be distributed to the state "for use in funding State and local law enforcement and public safety agencies' mission-related radio communications capabilities." TV stations operating in this band would not have to move until the end of the DTV transition period. At that time they would have to "surrender any license to operate such a television broadcast station, or permit to construct such a television broadcasting station, to the Commission for reallocation under this Act within 30 days after that date."
I have obtained the full text of the bill from the Government Printing Office and copies are available here, in Text format (37k) or in PDF format (170k).
Space scientists, using the European Space Agency - NASA Solar Heliospheric (SOHO) satellite have produced dramatic pictures showing the origin and propagation of large solar explosions. A video showing the explosions and other interesting phenomena was shown in Seattle Saturday at the annual meeting of the American Association for the Advancement of Science. Dr. Guenter Brueckner of the Naval Research Laboratory presented the video. He said
""I spend my life examining the Sun, but this movie is a special thrill," Brueckner said. "For a moment, I forget the years of effort that went into creating LASCO and SOHO, and leave aside the many points of scientific importance in the images. I am happy to marvel at a new impression of our busy star that gives us life, and which affects our environment in many ways that we are only now beginning to understand."
More information is available in a NASA Press Release and a Naval Research Laboratory Press Release. The Naval Research Laboratory's SOHO/LASCO home page has images from the observatory. Images related to the NRL press release are also available.
Recent rule making has significantly changed the way licensees and manufacturers of transmitters have to deal with the issue of safety and protection from excessive RF radiation. In preparation for the final revision to these rules, the FCC has established an RF-Safety web page. For those awaiting the revised version of OST-65 "Evaluating Compliance With FCC-Specified Guidelines for Human Exposure to Radiofrequency Radiation ", the FCC said it would be available from that location in the near future.
If you visit hamfests or read the popular scanner magazines, you may have caught someone selling scanner modifications that allow popular scanners to receive the forbidden cellular bands. The FCC has noticed this too, and Thursday it released a Public Notice stating that it considered the modification of scanners to receive cellular frequencies the same as manufacturing an illegal scanner. Specifically, it said:
"The modification of scanners on a substantial scale to receive cellular frequencies will be considered to constitute manufacture of such equipment in violation of FCC Rules. Entities engaged in such activity are cautioned to cease advertising and/or performing any such activity immediately."
Most scanner enthusiasts are aware it is now illegal to sell scanners that can receive cellular frequencies or are capable of "readily being altered by the user" to receive them. In this Public Notice, the Commission outlined exactly what units this applies to. It said that they include, but is are not limited to, those scanners
"for which the ability to receive cellular telephone frequencies can be added by clipping the leads of, or installing, a simple component, such as a diode, resistor and/or jumper wire;replacing a plug-in semiconductor chip; or programming a semiconductor chip using special access codes or an external device."
Today the FCC released a Report and Order that, it said,
"will provide manufacturers greater flexibility in marketing their products by applying to all RF devices the same, less restrictive marketing regulations that now apply only to industrial, scientific and medical (ISM) devices and to certain types of digital devices. In particular, the new rules will allow all RF devices in the development, design or preproduction stages to be advertised, displayed, and offered for sale to distributors and retailers prior to a demonstration of compliance with the applicable technical standards and compliance with the applicable equipment authorization procedure."
The Report and Order also eliminated the need for obtaining an experimental license for compliance testing, demonstrations or performance evaluation if the product is one that would not normally require a station licenses. This includes equipment operating under Part 15 and some systems operating under Part 95. If a station license is required for normal operation, the Commission is given several options, including issuing a station license, an STA or a Part 5 experimental/developmental license.
The Commission also moved the responsibility for certifying modified equipment from the manufacturer to the party doing the modification. Under the new rules, "the party performing the modifications will be responsible for ensuring continued compliance with the regulations and will be required to relabel the product with its name, address and telephone number in order to identify clearly the new responsible party." The Report and Order said
"A party that modifies an authorized product, even a modification falling within the purview of a Class I permissive change, becomes responsible for the compliance of that product, unless there is a specific authorization from the grantee (or manufacturer or importer for verified products or products authorized under a declaration of conformity) permitting the modifications, i.e., the grantee of the product continues to accept responsibility for the modified product."
Wavephore today announced the creation of "WaveTop - a nationwide broadcast medium for the home PC. The new broadcast service will deliver entertainment and information programming via existing TV broadcasting signals without the bottleneck of the Internet or tying up phone lines.", The service will use the broadcast signals of PBS National Datacast's 264 PBS member stations, reaching 99 percent of U.S. TV households. The system is based on Intel's Intercast platform. Some of the seven content categories will be broadcast to users' PCs, including "RadioTop", an FM-like radio station, "SoftTop" new and updated software and "NewsTop" offering multimedia content. Full details are available on WavePhore's What's New page.
In an Order released Friday, the FCC's Cable Bureau said
"The rule governing over-the-air reception devices applies to restrictions on antennas and dishes installed where the viewer has a direct or indirect ownership of property which is within his or her exclusive use or control. The rule applies to installation in or on a manufactured home owned by a viewer living in a land lease community because the owner of the manufactured home has an ownership interest in, and exclusive use or control of, the property in which he or she resides even though the home rests on land leased from the park owner."See the Order for more details.
In a Notice of Forfeiture released last week and made available on the 'Net today the FCC's Compliance and Information Bureau concluded the $20,000 forfeiture against Ace Communications was warranted. Ace was charged with marketing scanning receivers without obtaining an equipment authorization by the Commission as required by the Commission's marketing rules. The notice said no authorization would have been granted because the scanners in question were able to tune to cellular radio frequencies. More details are available in the Notice of Forfeiture.
In a conference sponsored by the NAB (National Association of Broadcasters) , Bruce Allan, Vice President for Technology and Business Development at Thomson Consumer Electronics said that a recent survey found that after seeing a side-by-side comparison of HDTV and SDTV, prospective large screen set buyers "expressed a willingness to to pay an additional $1200 to upgrade their main TV to high-definition performance." He also noted that consumers usually replace their primary TV receivers every seven years, "so their decisions will focus on the incremental investment to upgrade to the improvements in quality that HDTV provides." He expected prototype HDTVs to debut at the Consumer Electronics Show next January, with production models available in the second half of 1998, when the first HDTV broadcasts will begin.
CAI Wireless Systems, Inc. in a Press Release issued today, announced it had been granted permanent authorization from FCC to use its MMDS wireless spectrum for fixed two-way video, voice and data services in the Boston market. Jared E. Abbruzzese, CAI's chairman and CEO, said the authorizations "are a major step forward in allowing the development of a Wireless Information Network (WIN), a wireless full-service network providing digital video, voice and data services." The two-way system uses highly directional antennas at the customer's site to transmit and receive information from cell sites located in and around the Boston area.
One of the problems caused by the rapid expansion of digital technology is that business models become out of date quickly. CAI's president John J. Prisco comments show how his company is addressing the problem:
The key to the WIN platform is its flexibility. Once developed, we will have the ability to deliver two-way services in targeted areas of Boston while simultaneously delivering one-way data and digital video to other areas of the market. In the end, it will be market economics that decide what services are provided and where. Indeed, as this process develops, the term `wireless cable' as a business description of CAI should become unduly limited and outdated.
Yesterday the FCC's Office of Engineering and Technology released its monthly list of experimental licenses granted in December. Channel 13 TV broadcasters in Southern California may be interested in WA2XFV, a license granted to Fred Daniel, DBA Orion Telecom, to use 216-218 and 219-220 MHz. for the test and development of an improved Automated Maritime Telecommunications System. Other interesting licensed included WA2XFA, to Baldwin Piano and Organ Company, to use 285-322 MHz. and 410-470 MHz. to design and test a digital RF remote control link and WA2XEL, to AT&T Corp., for experiments in the 38-40 GHz. range to evaluate the effects of atmospheric anomalies on millimeter wave propagation.
GE American Communications, Inc. (GE Americom), announced the successful launch of its new GE-2 communications satellite. An Ariane 44L rocket was used to launch the satellite into orbit late Thursday. GE said that, so far, all systems on the satellite are operating normally. The satellite was built by Lockheed Martin Telecommunications and features 36 MHz. bandwidth C and Ku-band transponders, a shaped beam reflector antenna design and up to 60 watts of Ku-band power. The orbital location will be 85 degrees West Longitude. Primestar, will use GE-2's Ku transponders to provide its direct to home service. On the C-band side, expect to see some Spacenet 2 customers move to GE-2.
Scientists are taking a three pronged approach to studying the aurora this winter. The aurora will be observed on the ground, from a Saber 60 jet aircraft and from the Fast Auroral Snapshot (FAST) Explorer satellite. A report on the project from the Geophysical Institute quoted Professor Hans Nielsen comparing the auroral displays seen on Earth to an image seen on a television screen. saying that scientists know the sun is the power source of the aurora, just as electricity is the power source of a television set. "Using this analogy, the FAST satellite is designed to fly back in the inner workings of the TV, where the picture is forming. We want to find out exactly how the auroral picture forms and what processes create it."
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Last modified February 23, 1997 by Doug Lung email@example.com
Copyright © 1997 H. Douglas Lung