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.

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June 12, 2000 - Issue 218 Final Edition

FCC Establishes New Wireless Medical Telemetry Service (June 12)
The Federal Communications Commission has assigned the frequencies from 608-614 MHz (TV Channel 37 but reserved for radio astronomy), 1395-1400 MHz (used for some government operations) and 1429-1432 MHz (also used by the government) to a new Wireless Medical Telemetry Service (WMTS). Maximum field strength allowed in the 608-614 MHz band is 200 mV/m measured at 3 meters with a bandwidth of 120 kHz +/- 20 kHz using a CISPR quasi-peak detector. In the other two bands, maximum allowed field strength is 740 mV/m measured at 3 meters over a 1 MHz bandwidth using an average reading detector.

Medical telemetry equipment is not allowed to cause harmful interference to radio astronomy operations in the 608-614 MHz band and must be coordinated under FCC rules Section 95.1119. Non-medical telemetry government operations are secondary to WMTS operations in the 1390-1400 and 1429-1432 MHz bands, although government operations authorized as of March 22, 1995 will be fully protected until January 1, 2009 in the 1390-1400 MHz band and January 1, 2004 in the 1429-1432 MHz band.

WMTS will exist was one of the Citizen's Band services contained in Part 95 of the rules. Equipment used in the service will be "licensed by rule". Only health care providers are are eligible to operate transmitters in the WMTS.

For more information on WMTS, including background on the need to move medical telemetry to more protected frequencies than those previously authorized on TV channels on a secondary basis under Part 15 and on frequencies reserved for low power operation under Part 90, refer to the Report and Order in ET Docket 99-255/PR DOcket 92-235, Amendment of Parts 2 and 95 of the Commission's Rules to Create a Wireless Medical Telemetry Service available on-line inas a plain text file - fcc00211.txt and Microsoft Word file - fcc00211.doc. Also see the FCC News Release FCC Establishes New Wireless Medical Telemetry Service (nret0009) for general information.

FCC Requests Comment on Rules for Satellite Carriage of Broadcast Signals (June 9)
The FCC has launched another proceeding in its implementation of the Satellite Home Viewer Improvement Act (SHVIA). The general purpose of SHVIA is to place satellite carriers on an equal footing with local cable television operators regarding availability of broadcast programming. In a Notice of Proposed Rule Making adopted May 31 and released June 9, 2000, the FCC seeks comment on topics including: carriage obligations and definitions; market definitions; delivery of a good quality signal; duplicating signals; channel positioning; content to be carried; material degradation; digital television obligations; compensation for carriage; and remedies for carriage violations.

The SHVIA legislation requires satellite carriers, by January 1, 2002, to carry upon request all local broadcast stations' signals in local markets in which the satellite carriers carry at least one broadcast station signal licensed to the suject television market, pursuant to Section 122 of title 18 of the US Code. Details on the non-technical aspects of the NPRM are not discussed here. Refer to the Notice of Proposed Rule Making for details on carriage requirements and obligations.

The Act states that, "A television broadcast station asserting its right to carriage under subsection (a) shall be required to bear the costs associated with delivering a good quality signal to the designated local receive facility of the satellite carrier or to another facility that is acceptable to at least one-half the stations asserting the right to carriage in the local market." The FCC NPRM states, "A host of novel technical and definitional questions arise under this particular provision." It continues, "There are a variety of possible technical configurations that a satellite carrier might use to receive, uplink, and distribute local market broadcast signals. ...It appears likely that the most economically feasible means would be to aggregate the signals in each local market at one point and deliver them over the facilities of an interstate telecommunications carrier to the uplink site(s). If this is correct, the 'local receive facility' provider, which acts as the central processing facility for local television signals that will eventually be uplinked to the appropriate satellite.would be co-located at suitable carrier's switching center or 'point-of-presence'." The FCC seeks comment on whether POPs should be considered the "local receive facility" for purposes of the Act. The FCC noted that these facilities could resemble a cable operator's headend, because that is where signals are received and processed. Comment is sought "on the parameters under which a satellite carrier may construct and designate such a facility, " and, "on other reception points a satellite carrier can consider to satisfy the provision's requirements," and "on the procedures by which a satellite carrier must inform local market television stations of the location of the receive facility."

The FCC also wants comments about what constitutes a "good quality signal", as that term is used in Section 338. Under current cable rules, TV stations must deliver an RF level of -45 dBm for UHF signals or -49 dBm for VHF signals at the input terminals of the signal processing equipment to be considered eligible for carriage. If the broadcaster doesn't meet this requirement, it can provide the equipment necessary to improve its signal to the required level and gain carriage rights. The FCC questions whether the signal quality parameters under Section 614 and in the FCC's cable regulations are appropriate in the satellite carriage context. Cable regulations also specify methods for measuring the signal, including measurements over a 24-hour period if the initial reading is less that -51 dBm for a UHF station. Other signal quality measurement issues are discussed in the NPRM.

FCC cable rules state, "The signals of local commercial television stations that a cable operator carries shall be carried without material degradation." The FCC notes that degradation occurs when video signals are digitally compressed for transmission and notes that MPEG-2 supports a wide range of compression ratios and data rates. The NPRM discusses areas in the transmission chain where degradation can occur and specifically notes that "degradation may result when the satellite carrier encodes an analog broadcast signal and readies it for digital retransmission. During the encoding process, certain artifacts may be introduced into the original material that would have an effect on picture quality. The most dominant artifact is quantization noise in the picture. This effect is often visible on edges of subjects and textured areas of the image. It is caused when there is a high amount of picture detail along with a high degree of picture activity and levels of quantization are restricted due to data rate reduction. Random noise can also be introduced into the source video. This can result in activity or 'busyness' in detail areas of the picture and tiling or flicker in other areas of the picture. Such effects are caused by the encoder attempting to encode random noise. During the encoding process, data rate reduction in combination with rapid picture changes may result in another artifact known as the 'dirty window,' where noise appears stationary while the images behind it are moving."

The NPRM asks, "when a broadcast television station freezes, 'tiles' or looks 'dirty' due to a satellite carrier's choice of encoding and compression techniques, should that be considered 'material' or 'immaterial' degradation?" The FCC also seeks comment on whether there are certain compression ratios or encoding techniques that should be prohibited because their use would result in material degradation. The FCC notes "questions arise as to what standards and measurement techniques the Commission should employ where specific broadcast signal quality disputes arise," and said, "We seek suggestions for measurement standards that may be used in addressing signal degradation issues."

The FCC NPRM also considers how cable regulations requiring the Commission to "initiate a proceeding to establish any changes in the signal carriage requirements of cable television systems necessary to ensure cable carriage of such broadcast signals of local commercial television stations which have been changed to conform with such modified standards" would apply to satellite systems and how this affects treatment of broadcast digital TV signals.

Broadcasters, cable companies and satellite operators should take time to review the complete Notice of Proposed Rule Making - Implementation of the Satellite Home Viewer Improvement Act of 1999 - Broadcast Signal Carriage Issues. While the application of decisions in this rule making is limited to implementation of the SHVIA, the outcome is likely to influence the discussion of quality issues for other services using digitally compressed video, both inside and outside the FCC. The full text of the NPRM is available as ASCII text file fcc00195.txt and as a Microsoft Word file fcc00195.doc. The FCC News Release FCC Seeks Comment on Rules for Satellite Carriage of Broadcast Signals provides a non-technical overview of the NPRM.

FCC Satellite Applications Accepted for Filing (June 8)
The FCC Satellite Policy Branch released Report SAT-00047 - June 8, 2000 listing satellite applications accepted for filing. GE American Communications requested Special Temporary Authority to test its GE-7 satellite at 146 degrees West Longitude for up to 90 days prior to its commencement of service at 146 degrees W.L. GE-7 is scheduled for launch in July 2000.

Telesat Canada filed the technical information for its Anik E1 and E2 satellites as required by Section 25.114 of the FCC's rules. The FCC released an order on December 9, 1999 permitting Anik E1 and E2 to be added to the Commission's "Alsat" list, with certain conditions. Telesat requests the FCC determine that these satellites can operate interference free in a two-degree spacing environment. It asked the FCC to removed the conditions requiring operation of Anik E1 and Anik E2 on a non-interference basis relative to two degree compliant satellites on the Commission's Permitted Space Station list.

DTV - ATSC Approves PSIP Enhancements (June 7)
The Advanced Television Systems Committee (ATSC) has revised its Program and System Information Protocol (PSIP) standard to provide for "Directed Channel Change (DCC)" and to clarify some existing aspects of the standard.

DCC, as the name implies, allows broadcasters to direct a DCC equipped receiver to change channels to receive targeted commercials, localized news stories, weather reports and other specialized information. Viewers would enter information such as their zip code and desired subjects into their DCC equipped receiver. A broadcaster could use the viewer's category of DCC request to direct a viewer to a program containing subject matter they want to what.

Mark Richer, ATSC Executive Director, explained, "Broadcasters may transmit multiple programs simultaneously using the ATSC Standard. The DCC equipped receiver will automatically switch to a specific program or commercial based upon the information voluntarily entered by the consumer."

This information is from the ATSC Press Release ATSC Approves Enhancements for PSIP Standard. This link is a PDF file. It can be viewed with the free Adobe Acrobat Reader.

OTHER Items of Interest

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Last modified July 4, 2000 by Doug Lung dlung@xmtr.com
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