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 18 - Issue 187

October 25, 1999 - Issue 188 Final Edition

FCC Releases Experimental Application Grants for August (Oct. 22)
The FCC Office of Engineering and Technology released another of its periodic listings of Experimental Actions (pnet9023) listing grants of experimental applications. The list for August 1999 included some interesting grants. Although most new communications systems are designed for frequencies above 500 MHz, there is still interest in the spectrum below 30 MHz. Helixing Inc. received a license to operate on 185, 530 and 1620 kHz for antenna testing. Flash Comm was authorized to operate between 3155 and 26960 kHz for HF propagation testing in all fifty U.S. states. The Geophysical Institute at the University of Alaska was allowed to operate between 8000 and 19990 kHz as part of the Super Dual Aurora Radar Network. The Network is "used to measure global scale magnetospheric convection by observing plasma motion..."

In the shorter wavelengths, several companies received grants in the 17.3-20 GHz, 30 GHz and 40 GHz bands for testing low earth orbit satellite systems. L-3 Communications Satellite Transmission Systems was licensed to operate in the 2.1-2.7 GHz band for demonstation of a fixed wireless loop system for use outside of the United States.

Refer to the complete list of Experimental Actions (pnet9023) for additional details and a complete list of the grants.

FCC Allocates Spectrum for Intelligent Transportation Service Communications (Oct. 22)
In a Report and Order - ET Docket 98-95 (FCC 99-305) released today the FCC allocated the spectrum at 5.850-5.925 GHz to the mobile service. The spectrum is for use by Dedicated Short Range Communications (DSRC) systems operating in the Intelligent Transportation System (ITS) radio service. The DSRC systems would be used to transmit information between vehicles and roadside systems.

The FCC defines DSRC service as:
The use of non-voice radio techniques to transfer data over short distances between roadside and mobile radio units, between mobile units, and between portable and mobile units to perform operations related to the improvement of traffic flow, traffic safety and other intelligent transportation service applications in a variety of public and commercial environments. DSRC systems may also transmit status and instructional messages related to the units involved.

The 5.850-5.925 GHz spectrum is currently allocated internationally for Fixed Services, Fixed Satellite Service (FSS) Earth to Space uplinks and Mobile Services. In Region 2, which includes the U.S, the band is allocated to the Amateur radio service and the Radiolocation service on a secondary basis. In the U.S., the band is allocated on a co-primary basis for the Government's Radiolocation Service, which includes high power military radar systems. ISM and unlicensed Part 15 devices are allowed in the 5.850-5.875 GHz portion of the band. The FCC rejected requests by the American Radio Relay League (ARRL) that the 75 MHz allocation was too large and alternative spectrum above 40 GHz should be considered.

The FCC will allow the Amateur radio service to share the spectrum on a secondary basis. FSS operations would also be allowed to continue operating in the band. With regards to the high power government radar operations, the FCC found sharing is possible with proper coordination. DSRC applications cannot claim protection from existing radar operations, but new radar installations deployed subsequent to DSRC implementation would have to coordinate with the incumbent DSRC operations.

DSRC operations would be allowed a maximum peak transmit output power not exceeding 750 mW or 28.8 dBm with up to 16 dBi in antenna gain. If higher gain transmitting antennas are used, power must be reduced to compensate for the extra gain. The devices maximum EIRP shall not exceed 30 W EIRP. Transmit power may be increased to account to line losses due to long transmission cables. DSRC devices must comply with RF safety guidelines contained in the Second Memorandum Opinion and Order in ET Docket 93-62.

Refer to the Report and Order linked to above for full details.

FCC Responds to ABC 20/20 Story on Cell Phone RF Exposure Safety (Oct. 21)
The FCC issued a News Release titled Safety Guidelines for Hand-Held Cellular Telephones addressing cell phone RF safety issues raised by the ABC 20/20 news show aired on October 20. The story reported that some cell phones it tested failed to comply with FCC RF exposure guidelines. The FCC release said, "Whether these phones are not in compliance with our limits remains to be determined, since variability in evaluation procedures is often an issue and the specific test procedures used by the European laboratory that conducted the tests for ABC have to be review further." It also stated that, "The values of exposure reported by ABC were well within "the large margin of safety between allowed levels of exposure and exposure thresholds identified with "known adverse health effects."

The FCC called on standard-setting committees "to develop specific uniform procedures and methodologies for testing cell phone radiofrequency emissions." The FCC warned "If they do not act promptly to finalize standardized testing methods, the Commission will mandate action on its own."

The News Release referred readers to the FCC RF Safety Web Site.

INDUSTRY - Acrodyne Announces Move to New, Larger, Facilities (Oct. 20)
Acrodyne Industries, Inc. said it was moving its entire operation to new corporate headquarters in Oaks, Montgomery County, PA outside of Philadelphia. The new 60,000 square foot facility will include corporate headquarters, a state-of-the-art manufacturing facility and a training facility. Relocation is scheduled for the middle of 2000. Nat Ostroff, Chairman of the Board of Acrodyne, remarked, "I am extremely pleased with the design and location of the new facility and look forward to a rapid expansion of Acrodyne's product capabilities. I am particularly grateful for the support of the Sinclair Broadcast Group in helping us obtain this modern facility." Robert Mancuso, President and CEO of Acrodyne said the new facility "...will provide the ability for rapid growth without compromising our present employees' status and also entice additional professional personnel to join Acrodyne."

See the Acrodyne Press Release for more information on the move.

DTV - Sinclair Responds to FCC OET Report on COFDM (Oct. 19)
Sinclair felt it necessary to file comments with the FCC concerning the DTV Report on COFDM and 8-VSB Performance. See the October 4, 1999 RF Current for a summary of the Report. In its comments, Sinclair said it believes that, "overall, OET's report supports its views regarding the benefits of broadcaster flexibility." However, Sinclair stated its concern that critical finding in the OET Report rely on technical data from Oak Technology Ltd.'s data from the Sinclair tests. Refer to the Oak Technology White Paper on data captured from the Sinclair Broadcast Transmission tests in Baltimore. Sinclair included a statement that Oak made that said "The Oak Report was deliberately intended to give a lot of generally intersting information whilst withholding vital information which would be useful to Oak's competitors." " The information not disclosed was data on the dynamic multipath conditions which Sinclair found at most of the 31 sites within the A grade contour. Regarding the ability of first generation 8-VSB signals to work in these environments, the Oak statement said "It is the time variation that kills them, and this is the information which we did not provide." The statement continued, "Although I do not know the details, it would seem to me that if anyone has used information in this report as a basis for demonstrating that a demodulator works for these channels, it shows a rather naive attitude."

Sinclair also disputed the statement in the OET Report attributed to Bruce Allen that Harris tested a DTV receiver with an improved equalizer and received 8-VSB service at all of the Sinclair sites. Sinclair pointed out that it had not disclosed the location of all forty of its sites and that of the five public demonstation sites, at least one of the indoor sites was owned by a Sinclair employee who "indicates that no such testing occurred." Based on this, Sinclair concluded that "to the extend that Harris and Hitachi actually have technical evidence that second-generation 8-VSB receivers or other new technologies permit reliable indoor reception, such support must have been derived from simulated tests based on the misleading Oak data."

Sinclair questioned OET's statement that the COFDM system would have a 5 percent data rate disadvantage compaired to 8-VSB. Sinclair said that the COFDM modulator they used could have transmitted data at rates from 4 to 24 Mbps and that the data rate selected was chosen as a data rate that would support HDTV service while overcoming complex multipath effects. Sinclair also said that a modern COFDM transmitter could use an occupied bandwidth of 5.7 MHz, rather than the 5.625 MHz the OET Report indicated would be required to comply with FCC emission bandwidth requirements.

Sinclair pointed to its field tests that showed that under real-world conditions, the power advantage enjoyed by 8-VSB decreases to 2 dB, instead of the 4 dB mentioned in the OET Report. According to Sinclair, that 2 dB difference "does not lead to any material difference in the receivability of 8-VSB and COFDM signals."

The Sinclair comments address several other issues in the OET Report, including the cost of allowing COFDM for DTV, impulse noise effects and the historical background concerning COFDM in 1995-1996 when the U.S. DTV standard was being set, The Sinclair DTV Page links to a page with comments on the FCC's OET Report.

FCC Satellite Applications and Grants (Oct. 19)
The FCC has granted Loral Orion Services, Inc final authority to launch its Orion F2 satellite to the 15 degree West Longitude orbital location for in-orbit testing consistent with an earlier Special Temporary Authority. The FCC, however, did not authorize a final authority to provide commercial service from this or any other orbital location. See FCC Order and Authorization (DA 99-2222) for additional information.

PanAmSat filed a request for Special Temporary Authority to conduct in-orbit testing of its Galaxy XI satellite at 78.5 degrees West Longitude for up to ninety days after the launch of the satellite. PanAmSat has a pending application to operate Galaxy XI at 99 degrees West Longitude until it can launch Galaxy VI-R into that location. At that time, it wants to move Galaxy XI to 91 degrees W.L. Galaxy XI is scheduled to be launched in November this year. Comments on this request may be filed on or before October 29, 1999. See Satellite Policy Branch Report Number SAT-00028 (PNIN9206) for more information. Note that this links to an Adobe Acrobat PDF file.

FCC Proposes Changes to Conducted Emission Limits Below 30 MHz (Oct. 19)
The FCC has released a Notice of Proposed Rule Making - Conducted Emissions LImits Below 30 MHz for Equipment Regulated under Parts 15 and 18 of the Commission's Rules (ET Docket 98-80) which would adopt the international CISPR limits in place of the current FCC conducted emssion standards.

The FCC agreed with a Microsoft request that some relief be provided for conducted emissions on the fundamental frequency of intentional radiators operating below 30 MHz. Under the proposed rules, the level of the emissiosn conducted into the AC power lines at the transmitter's fundamental frequency could be ignored provided the energy radiated from the AC power lines is included as part of the total radiated emissions from the intentional radiator. Testing of radiated emission levels at a minimum of three installations representative of typical installation sites. The FCC requested comments on how this increased testing burdgen could be reduced through alternative test procedures, "especially test procedures that would enable the equipment to be subjected to a single test at a laboratory open field test site."

The FCC rejected the National Association of Broadcaster's request to set emission limits for incidental radiators such as electric motors. However, consumer ISM equipment such as RF lighting devices, induction cooking ranges, ultrasonic equipment and microwave ovens would be required to comply with international CISPR Publication 11 limits. Non-consumer ultrasonic and magnetic resonance equipment used for medical diagnostic and monitoring applications and additional industrial or commercial ISM equipment would not be subject to the CISPR limits.

The Notice of Proposed Rule Making contains the text of the proposed rule changes. Refer to it for a complete discussion the changes, specific requests for comments and disposition of comments filed earlier in the proceeding.

SPECTRUM - CEMA Says Early Auction Sells UHF Channel 60-62 and 65-67 Spectrum Short (Oct. 19)
CEMA said a provision in the 1999 Defense Appropriations Bill (HR 2561) mandates the FCC auction UHF TV channels 60-62 and 65-67 by September 30, 2000 to have the proceeds in the U.S. Treasury before the end of the fiscal year. CEMA President Gary Shapiro warned "Congress has once again intruded into spectrum management, setting the stage for a potential giveaway of what otherwise would be very valuable spectrum. This accelerated timeline does not allow the FCC time to allocate the spectrum in the manner that best serves the public interest. The new date precludes the creation of new, innovative services for consumers and ensures that the public will not get full market value for the spectrum at auction."

CEMA had proposed the UHF TV channels be used for a new Mobile Multimedia Broadcasting Service (see RF Current - August 9, 1999). Shapiro explained, "This spectrum would be of enormous value if the FCC had the time to adopt service rules and bidders had the opportunity to develop business plans for the optimum use of the spectrum. Our proposal to establish MMBS would provide high value for the spectrum, strong returns to the Treasury and exciting new entertainment and information services for consumers."

This information is from CEMA news release Budget Bill Sells Spectrum Short.

DTV - CEMA Files Opposition and Motion for Immediate Dismissal of Sinclair DTV COFDM Petition (Oct. 14)
The Consumer Electronics Manufacturers Assocation (CEMA) filed an Opposition to Petition for Expedited Rulemaking and Motion for its Immediate Dismissal asking the FCC to decline to accept Sinclair's Petition for Expedited Rulemaking to take action leading to inclusion of COFDM in the U.S. DTV standard. CEMA's Opposition said "The Petition fails to assert any valid basis for reopening the digital television standards proceeding at this late date, and presents only arguments that are repetitive of those previously considered and that otherwise do not warrant consideration in the public interest." CEMA warned, "Re-opening the proceeding on a DTV standard years after its adoption by the Commission will benefit no one but the handful of broadcasters desiring to delay the transition to digital broadcasting. No matter how some may attempt to cast the issue, opening a proceeding -- particularly a needless proceeding such as is the one requested by Sinclair -- would create the type of uncertainty that will inhibit purchasing equipment and financing new and improved products and programs."

CEMA placed the blame for the poor performance of 8-VSB in Sinclair's Baltimore tests squarely on the receivers, rejecting any argument that the transmission system itself was to blame. The CEMA Opposition ignored the fundamental differences in the characteristics of two modulation methods, stating: "The Commission also must consider that Sinclair's basis for requesting this extraordinary action -- that the DTV standard based on 8-VSB is deficient -- is demonstrably and totally incorrect. The most glaring of Sinclair's false assumptions is that the fault is with the transmission standard if multipath interrupts digital reception in one or more locations. One with even a passing familiarity with the DTV standard would understand that for the DTV 8-VSB standard, multipath reception is determined not by the transmitted signal but by the technical characteristics of the digital television receivers."

CEMA didn't argue that multipath posed challenges for 8-VSB. The Opposition explained, "When the first broadcasts began in 1998, a number of entities, like Sinclair now, recognized the necessity to improve reception in high signal urban areas. Unlke Sinclair, however, these experts recognized that the true technical nature of the difficulty was not with the transmission standard, but with the design range of receiver equalizers." "Today's chips containing the new equalizers have been manufacturered and tested in the laboratory and confirmed in the field." CEMA expressed confidence that these chips would solve the problems documented in the Sinclair demonstrations. The report mentioned that a paper presented at the IEEE Broadcast Technical Symposium in Washington on 8-VSB receivers testing which included some of the new designs "conclusively demonstrate the magnitude of improvement over first generation implementations."

CEMA was concerned that the pioneers that purchased the first DTV sets would be disenfranchised, commenting that " consumer electronics manufacturers have sold more than three hundred million dollars worth of equipment that uses the 8-VSB standard." CEMA used the AM stereo debacle to show that allowing the marketplace to determine between multiple standards didn't work. CEMA warned:

"The Sinclair Petition guarantees nothing but uncertainty. In effect, Sinclair is proposing that manufacturers embark on a journey without a destination. First, if the full rulemaking proceeding is carried to its conclusion, it is theoretically possible that a dual 8-VSB/COFDM standard could be adopted. In reaching this result, COFDM would have to undergo the exhaustive and time-consuming research, testing, and scrutiny (both by all affected industries and the Commission) that produced the ATSC DTV standard before it could be considered suitable for U.S. broadcasters. In the alternative, for the same reasons that led the ATSC process to reject COFDM after extensive debate and study, any new standard-vetting process could again deem COFDM inadequate for the United States."

The CEMA Opposition also expressed concern about the need to do new interference tests. It said that Sinclair did not provide precise technical specifications for the alternative transmission system it was proposing, making it difficult to do comparisons. CEMA warned, "It is also extremely unlikely that the DTV Table of Allotments could accommodate the introduction of COFDM transmissions." (The FCC OET report said its "...analysis indicates that if the 1 MW cap is retained, the overall increase in interference to NTSC service would be generally small.", but added that "for a small number of NTSC stations, population service loss would be more significant." It concluded, "At this time, it is unclear whether any changes in the DTV Table of Allotments would be needed to accommodate a change to COFDM.")

See the CEMA FCC filing Opposition to Petition for Expedited Rulemaking and Motion of its Immediate Dismissal (Adobe PDF). A report on Sinclair's response will appear in the November 1 RF Current.

OTHER Items of Interest

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Last modified November 4, 1999 by Doug Lung dlung@transmitter.com
Copyright 1999 H. Douglas Lung