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The Chapter 24 Newsletter is published monthly by Chapter 24 of the Society of Broadcast Engineers; Madison, Wisconsin. Original hard copy edited by Mike Norton on Pagemaker 5.0. Submissions of interest to the broadcast technical community are welcome. You can make your submissions by e-mail to:

© 1998 by SBE Chapter 24. Views expressed herein do not necessarily reflect the official positions of the Society, its officers, or its members. SBE Chapter 24 regrets, but is not liable for, any omissions or errors. The Chapter 24 Newsletter is published twelve times per year. Other SBE Chapters are permitted to use excerpts if attributed to the original author, sources, and SBE Chapter 24.

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This month's program will consist of the first Chapter 24 Youth Membership Night. Bob Miller, General Manager of WKOW-TV, will be the featured speaker. A tour of the facility will follow the meeting, with a Q & A session for students. Pizza will be served!

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Chapter 24 of the Society of Broadcast Engineers met on Wednesday, October 21, 1998 at the Marriott - Madison West, in Madison, Wisconsin. This meeting was in conjunction with the Broadcasters Clinic and the Upper Midwest region of the SBE. 10 Midwest chapters were represented: 24-Madison, 25-Indianapolis, 26-Chicago, 28-Milwaukee, 30-South Bend, 80-Fox Valley, 74-Midland (NE), 87-Holdrege (NE), 96-Rockford, and 112-Western Wisconsin. There were 42 members, and 8 guests present. 28 reported being certified.

The meeting was called to order by Chair Fred Sperry at 7:00 PM. Fred recognized the visiting SBE chapter members and guests. He also recognized those attendees who had recently received National SBE awards, Tom Smith for Frequency Coordination and Leonard Charles for Broadcast Engineering.

Leonard Charles, National SBE Board Member and Chapter Liaison, then gave the national level update, including the national meeting in Bellevue, Washington, and the SBE's efforts to save Broadcast Auxiliary Frequencies. He spoke of the upcoming exam schedule, new high school student recruitment, and announced that a student mentoring program is now under development. He also talked about the FCC's announcement of the elimination of the EAS authenticator list, and pending action on updated codes for the EAS and N.W.S. The SBE is also investigating Y2K EAS issues.

Leonard's 2nd National Board Term as head of the National EAS Committee is up next week, and he gave thanks for all of the support he has received over the last two years, and especially from his employer WISC-TV and his co-workers. He also thanked Gary Timm for his exhaustive work on the Wisconsin EAS.

Gary Timm then thanked Leonard and the SBE membership for their assistance with the development and implementation of the Wisconsin EAS.

Leonard Charles announced Larry Wilkins will replace him as national Chair of EAS, invited the members present to run for national SBE posts, and invited members to participate in Steve Bauder's DTV survey project.

Kevin Ruppert announced the winner for the annual SBE Cookie Bake-Off. Denise Maney was voted the winner.

Fred Sperry then adjourned the business portion of our meeting at 7:33 PM and opened the evening's program by introducing the guest speaker, John Reuter from Odetics.

Mr. Reuter spoke on preparing for the upcoming Year 2000 computer problems, as well as other lesser-known "date related" hardware and software difficulties that broadcasters must be prepared to handle.

Submitted by Lloyd Berg, Secretary

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In a Public Notice dated September 3, 1998, the FCC announced that it will discontinue the use of Authenticator Lists in EAS procedures. The wording of the Public Notice follows.

COMMISSION TO DISCONTINUE DISTRIBUTION OF EAS AUTHENTICATOR LISTS

With the concurrence of the Federal Emergency Management Agency (FEMA) and the White House Communications Agency (WHCA), the Commission will no longer distribute Emergency Alert System (EAS) authenticator lists. The lists, commonly referred to as the red envelopes, have been in use since the inception of the Emergency Broadcast System (EBS) in 1963. FEMA thanks the Commission for its on-going support of this important national security program.

When EAS was adopted by the Commission in 1994 to replace EBS, broadcasters and cable operators were required to install new EAS equipment. The new equipment can operate in an automatic mode without the need for human intervention and authentication. FEMA and WHCA were requested to comment on this matter and they recommended that use of the authenticator lists be discontinued.

Part 11 of the Commission's EAS rules will be amended to delete use of the authenticator lists. Also, the procedures in the EAS AM/FM and TV Handbooks will be revised to reflect that the use of the authenticator lists is discontinued. If you have any questions, please contact the FCC EAS Staff in the Compliance and Information Bureau at (202) 418-1220 or 418-1226 or by e-mail at EAS@fcc.gov.

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This is Part 26 in a series of articles about broadband networks. In this article, we'll conclude our discussion of the FCC rules governing signal egress from broadband networks.

As we have noted in previous articles (Parts 24 and 25), FCC rules regulating egress from broadband networks are contained in Part 76, Subpart K, of the Code of Federal Regulations. Part 76 covers Cable Television Service generally; the technical standards set forth in Subpart K apply to all broadband networks, CATV or otherwise.

This article is devoted to a discussion of a single rule: §76.611 - Basic Leakage Performance Criteria.

THE EGRESS BUBBLE

Before we discuss the rule itself, we will digress a bit and discuss something called the "egress bubble."

The shape of the egress field generated a single leak is indeterminate. A cut cable may approximate a point source, radiating in all directions at random polarization angles. But a crack in a cable sheath is more likely to simulate a slot radiator, generating an egress field in a specific direction at a specific polarization.

The egress field generated by a number of leaks spread over a large geographic area is more easily characterized. Research conducted by an FCC Advisory Committee during the 70s indicates that the field takes the shape of a "bubble" over the distribution system. The following graph, taken from the Advisory Committee's Final Report illustrates this bubble:

This bubble may extend for several hundred feet above ground level. The field intensity of this bubble at any given altitude is a function of the number of leaks and the average intensity of these leaks. Obviously, if the field intensity of the bubble is sufficiently strong, it could cause interference to aeronautical communications systems.

The FCC's goal in establishing §76.611 is to require each cable television operator to determine, on an annual basis, a number which represents the field intensity of the bubble. This number is a "snapshot" of the cumulative egress emanating from all leaks during a specific time interval.

The resulting "snapshot" number must be reported to the FCC by July 1 of each year. If the reported number exceeds a specified value, the cable operator must cease operations until a sufficient number of leaks are repaired.

Of course, as a practical matter, no cable operator would ever report a number which exceeds the FCC's maximum permissible value. Every competently-managed cable system maintains an ongoing repair program to assure that the annual measurement will pass.

And that, of course, is precisely what the rules are intended to do in the first place: keep leakage under control.

MEASURING THE "SNAPSHOT" NUMBER

There are three different ways to measure the "snapshot" number, each obtained by a different procedure: CLI_INFINITY, CLI₃₀₀₀, and AIRSPACE. The cable operator can select any one of the three procedures. We will discuss each of these methods separately.

This method calculates a quantity called the "Cumulative Leakage Index" (CLI) which represents the total egress coming from the entire cable system. This is a ground-based measurement: each leak is measured on the ground and the CLI is then calculated from measurement data. The calculated value of CLI_INFINITY must not exceed 64.

I_INFINITY is calculated using the following formula:

Now that looks like a pretty scary formula. But the procedure it defines is actually quite straightforward if we break it down into steps:

Here's an example. Assume we measure 100% of the plant and find three leaks:

         E1 = 55 mV/m
         E2 = 65 mV/m
         E3 = 45 mV/m

Since E₃ is less than 50mV/m, we discard it. We then calculate:

         E12 = 3025
         E22 = 4225

Adding these quantities yields

         IINFINITY = 7250

Since we measured 100% of the plant, Q = 1, and the factor 1/Q drops out. Completing the calculation,

         CLIINFINITY = 10*log10(IINFINITY)
         CLIINFINITY = 10*log10(7250) = 38.6

Since 38.6 is less than 64, we pass. We report this value to the FCC.

This method also calculates a "Cumulative Leakage Index" (CLI). In this case, however, CLI₃₀₀₀ represents the total egress coming from the entire cable system as normalized to a point 3000 meters over the center of the distribution system. Theoretically, this method produces a more realistic estimate of the actual field intensity of the bubble at the center of the distribution system.

This is still a ground-based measurement: leaks are measured on the ground and the CLI is calculated from the measured data. However, we do some additional mathematical manipulation to determine the theoretical field intensity of each leak if we were to measure it from a hypothetical point 3000 meters over the center of the distribution system. The calculated value of CLI₃₀₀₀ must not exceed -7.

CLI₃₀₀₀ is calculated using the following formula:

where:

Compare these formulas with the formulas used to calculate CLI_INFINITY. The difference is the factor R_i in the denominator of the summation argument. R_i is the "slant height distance," in meters, from leak i to a point 3000 meters above the center of the distribution system. R_i is calculated from the formula

where r_i is the distance in meters from the center of the distribution system to leak i.

The following figure illustrates the situation. Note that R_i is simply the hypotenuse of a right triangle whose sides are r_i and 3000.

Let's take an example to illustrate this procedure. Again, we measure 100% of the plant and find three leaks:

         E1 = 55 mV/m; r1 = 3000 meters
         E2 = 65 mV/m; r2 = 7000 meters
         E3 = 45 mV/m; r3 = 1400 meters

And again, since E₃ is less than 50mV/m, we discard it. Using the above formulas, we then calculate

         I3000 = 0.000241

Again, since we measured 100% of the plant, Q = 1, and the factor 1/Q drops out. Completing the calculation,

         CLI3000 = 10*log10(I3000)
         CLI3000 = 10*log10(0.000241) = -36.2

Since -36.2 is less than -7, we pass. We report this value to the FCC.

WHAT'S THE DIFFERENCE?

So why are there two methods for calculating CLI? What's the difference between the two?

The answer to this question will become apparent if we examine a distribution system with many large leaks. Consider the four hypothetical cases shown in the following table:

Note that:

This illustrates a general rule: If the distribution system is relatively small, the r_i factor doesn't have much effect. But in a large system (larger than about 4 kilometers diameter), r_i becomes more significant.

Cable television technicians conducting CLI tests are keenly aware of this distinction:

The last method is straightforward in concept: direct measurement of the field intensity of the egress in the airspace above the distribution system. The specific rule states that the field intensity shall not exceed 10 mV/m at an altitude of 450 meters above the average terrain of the distribution system.

Actually making this measurement isn't so straightforward, however. An aircraft must be fitted with a special antenna (described by the FCC as a "well characterized antenna consisting of orthogonal resonant dipoles, parallel to and one quarter wavelength above ground plane of a diameter two meters or more at ground level"). The measurements are then made following a procedure that goes something like this:

Using this procedure is obviously an expensive proposition: the cost of making just one set of airspace measurements runs several thousand dollars. To the best of my knowledge, no cable television company owns the equipment to perform this test itself. However, a number of commercial firms are equipped to perform this test on a contract basis.

In view of the cost, why would any cable operator use airspace measurements?

Because it's an independent evaluation of the system's egress compliance, conducted by a (presumably) disinterested party. No employee of the system operator has a chance to fudge the numbers. An operator wishing to sell a system may include airspace measurements as part of the sale offer. An operator contemplating the purchase of a system may conduct airspace measurements as part of the due-diligence process.

HOW LONG IS A "SNAPSHOT"?

Given that the Basic Leakage Performance Criteria number is supposed to represent a "snapshot" of the system's egress performance, how long a time period is allowed to "take" the snapshot?

The FCC allows 90 days to conduct the CLI tests. This time period coincides with one regular quarterly-monitoring period. This period allows the cable operator time to find the leaks, measure them, log them, fix them, and then re-measure them for the CLI test. Following this procedure, the operator could theoretically end up reporting a CLI value of zero.

While this procedure might sound like "cheating," it's consistent with the FCC's goal: find the leaks and fix them!

By implication, the FCC also allows 90 days for the airspace measurement. However, for cost reasons, this almost never happens. Any cable operator who contracts for an airspace measurement had better be very confident that the system will pass the first time around.

HAS IT WORKED?

Rule §76.611 has been in effect since July 1, 1990. During this time period, nine sets of Basic Leakage Performance Criteria measurements have been reported to the FCC.

Has all this effort produced any net reduction in egress from cable television systems?

Michael Lance, the Deputy Chief of the Engineering and Technical Services Division of the FCC's Cable Services Bureau, thinks so. Mr. Lance is the FCC staff member responsible for reviewing the annual reports. He states that he has seen a consistent drop in the reported measurements every year since 1990.

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This ends our discussion of signal leakage. This series will resume in January with a discussion of headends.

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I am pleased to announce that the SBE National Board of Directors has accepted an invitation from Chapter 24 and the Broadcasters Clinic to host the 1999 SBE National Meeting. The meeting will take place in conjunction with next year's Broadcasters Clinic in Madison taking place October 19th - 21st. The Board of Directors accepted the invitation at their October 27th meeting that took place at the SBE National Meeting which was held in conjunction with Chapter 16's Electronic Media Expo in Bellevue, WA.

This should prove to be an exciting opportunity for Chapter 24 and it's members!

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Research volunteers are needed for a study on the competencies required of broadcast engineers to implement DTV. Steve Bauder, a graduate student at the University of Wisconsin-Stout and Chief Engineer of Wisconsin Public Television/Radio station WHWC, is conducting the research on behalf of the SBE.

Volunteers are needed to complete a survey in which they will be asked to rate the importance of various skills, knowledge and abilities compiled from a panel of leaders in the field of digital television. The only pre-requisite for participation is a cursory understanding of the technologies of digital television.

Please e-mail your interest in the study to: bauders@post.uwstout.edu

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• In a speech before the Personal Communication Industry Association Convention in Orlando recently, FCC Commissioner Susan Ness expressed support for amateur radio spectrum allocations. Ness said that spectrum auctions are primarily for assigning licenses, and "are not a substitute for the allocation process." She said, "we need to ensure that adequate spectrum is available for public safety purposes, for unlicensed - that is, Part 15 - uses, for the amateur service, and for experimental and scientific purposes. None of these needs would be met if auctions displaced judgment in the spectrum allocation process."

• The FCC has adopted its long-proposed Universal Licensing System, which will replace Amateur Radio Form 610 with a new Form 605. The new form will cover ship, aircraft, amateur, and general mobile radio services, and restricted and commercial operator applications. The action consolidates 40 existing forms into four ULS application forms, including the new Form 605. Amateurs will not yet be required to file electronically, but will have that option.

• The FCC has begun to crack its amateur enforcement whip. The Commission issued an Official Notice of Violation October 21 against James C. Thompson, KA2YBP, of New Jersey, who was accused by FCC inspectors with illegally retransmitting programs from an AM broadcast station on 40 meters and willfully interfering with an amateur network. The FCC also charged Thompson with failing to properly identify. It's the Commission's first amateur enforcement action since its consolidation of amateur enforcement within the Compliance and Information Bureau.

(Excerpts from November 1998 "QST" and the American Radio Relay League's October 30, 1998 "ARRL Letter")

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There will be four 10-day periods when SBE Certification exams will be offered in local chapters during 1999. Certification candidates will have more flexibility in choosing when to take an exam. To schedule an exam contact Jim Hermanson or Tim Trendt. For more information about SBE Certification contact Linda Godby-Emerick at the SBE National Office at (317) 253-1640 or lgodby@sbe.org.

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PACIFIC NORTHWEST ROLLS OUT RED CARPET FOR SBE NATIONAL MEETING

The 1998 SBE National Meeting was held October 27-29 in conjunction with Chapter 16's Electronic Media Expo in Bellevue, WA. More than 2,000 attendees and exhibitor personnel took part. The convention included two days of technical papers, more than 200 exhibit booths and the Ennes Workshops. Participants could also attend the SBE National Awards Dinner and the fall meeting of the national Board of Directors. Craig Tanner, Executive Director of the Advanced Television Systems Committee in Washington, D.C., served as keynote speaker at the Awards Dinner. Terry Baun was recognized with the SBE Fellow Award during the dinner. Leonard Charles was named Broadcast Engineer of the Year and Richard Farquhar, Educator of The Year.

NATIONAL BOARD OF DIRECTORS MEETING RE-CAP

SBE President Ed Miller presided over the October 27th meeting of the SBE Board of Directors in Bellevue, WA. The Board approved the National SBE budget for 1999. Finance Committee Chairman Bob Hess reported that the budget includes a 2% increase in revenue and a 1% increase in expenses. Regular Member dues will remain the same for the eighth year.

The Board authorized the Publications Committee to proceed with plans to develop a new "Chief Operators Handbook." Release is expected for early 1999. The Board authorized computer network, hardware and software upgrades for the National Office. Funds will come from long-term savings.

The Board also approved expanding the scope of the electronic newsletter, "Short Circuits." Beginning with the January 1999 issue, it will be sent to all members whose e-mail addresses are in the National Office database. Short Circuits provides information on SBE programs and activities in between issues of the quarterly THE SIGNAL. The new service will enhance the flow of information to many of our members.

The Board accepted the invitation of Chapter 24 in Madison, Wisconsin and the Broadcasters Clinic to host the 1999 National Meeting. Locations for the National Meeting were also tentatively scheduled for 2000 and 2001. Following approval by those host chapters, locations for those years will be announced.

MONTHLY HAMnet BRINGS SBE TO REMOTE AREAS

At 8:00 pm EST, 0000 GMT, on the second Sunday of each month, SBE Chapter 73 takes the air. Hal Hostetler, WA7BGX, of Tucson, Arizona, is the control station for the "meeting." Updates on SBE activities are given each month and participants can discuss technical issues and visit. HAMnet was originally begun to help serve members who lived too far to attend meetings of any regular chapter, but any amateur operator is welcome and encouraged to participate. Look for HAMnet on 14.205 mHz.

CHAPTER REBATE REPORTS DUE

Chapters are reminded to get in all of their chapter meeting reports for this year by December 31, 1998. Those chapters who have documented at least five meetings during 1998 will be eligible for the annual rebate, paid on June 1, 1999. Chapter reports, which include a brief description of the meeting and attendance list, should be mailed, faxed or e-mailed to Teresa Ransdell, Membership Coordinator at the SBE National Office.

MEMBERS ENCOURAGED TO PARTICIPATE IN NATIONAL GROUNDHOG JOB SHADOW DAY

The SBE Board has endorsed National Groundhog Job Shadow Day, February 2, 1999. Sponsored in part by "America's Promise, The Alliance For Youth," and chaired by USA Ret. General Colin Powell, National Goundhog Job Shadow Day will enable hundreds of thousands of students to participate in the second annual event that gives students a close-up look at how the skills they learn in school are put into action in the workplace.

SBE Members are encouraged to participate by having one student shadow them during the work day on February 2. Local Junior Achievement offices will be facilitating the student placements. More information on how to participate will follow in the December "Short Circuits."

Questions and comments about SBE may be e-mailed directly to Executive Director, John Poray at jporay@sbe.org.

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PROPOSED RULEMAKINGS

IB Docket No. 98-172; FCC 98-235

Redesignation of the 18 GHz Frequency Band, Blanket Licensing of Satellite Earth Stations in the Ka-band, and the Allocation of Additional Spectrum for Broadcast Satellite Use

The FCC is proposing to reallocate spectrum from 17.3-20.2 GHz for the use of satellite to earth station downlinks for a number of satellite services. Currently these frequencies are shared by a number of users, including broadcasters for point to point microwave relay use. Current users and applicants would be grandfathered, but new applicants would be given secondary status and would have to accept interference from the new satellite services. The FCC is asking for comments on the possible need to relocate the existing users if the new satellite services cannot avoid interfering with them.

The 17.3 GHz band will be assigned for direct broadcast satellite service. The following will have primary allocations, 17.7-18.3 for terrestrial fixed service, 18.3-18.55 GHz for geostationary orbit fixed satellite service, and 18.8-19.3 for non-geostationary orbit fixed satellite service. Co-primary designations with terrestrial fixed service use will include the 18,55-18.8 GHz band for geostationary orbit fixed satellite service feeder use (uplink) and 19.3-19.7 GHz band for mobile satellite service feeder use. The FCC is also planning to allocate 24.75-25.25 GHz for direct broadcast service uplinks, and 28.35-28.6 GHz and 29.5-30.0 GHz for other satellite uplink use.

This rulemaking is the result of a petition by Lockheed Martin, AT&T, Hughes Communications, Loral Space and Communications, and GE American with supporting comments by Teledesic.

Comments were due on November 5, 1998 with replies due on December 7, 1998. The FCC action was on September 17, 1998 and the notice was released on September 18, 1998. It was published in the FEDERAL REGISTER on October 8, 1998 on pages 54,100-54,104.

RM-9395; DA 98-2244

Petition for Rulemaking

The FCC is seeking comment on a petition for rulemaking From USAFormosa Digital Radio Partners, LP to amend Part 73 of the rules. USADR would like the FCC to adopt their in-band on-channel digital audio broadcasting system for use in the existing AM and FM broadcast bands.

Comments are due on December 23, 1998 and replies are due on January 25, 1999. The FCC released the public notice on November 6, 1998 and it is available on the FCC web site.

FINAL RULEMAKING

MM Docket No. 95-176;

FCC 98-236

Closed Captioning of Video Programming

The FCC has amended some of it's rules concerning closed captioning in response to a number of petitions for reconsideration.

All programming that was first exhibited after January 1, 1998 will have to be captioned by January 1, 2006. Under the original rules, the FCC called for 95% compliance. Programming first exhibited before January 1, 1998 is called exempt programming and 75% of this programming will have to be captioned by January 1, 2008. The amend rules are to clarify that this includes all programming by any distribution method including movies and home videos.

The FCC is also requiring ABC, CBS, Fox, and NBC and their affiliates in the top 25 markets to use live captioning instead of using TelePrompTer copy to be used in figuring compliance with the rules. New Networks are exempt during their first four years from launch or for four years from January 1, 1998 if they had not reached their fourth anniversary by that date.

The FCC also issued rules concerning the transitioning in of captioning for new DTV programming and Spanish language programming.

This action becomes effective on November 19, 1998 and was adopted on September 17, 1998. The notice was released on October 2, 1998 and published in the FEDERAL REGISTER on October 20, 1998 on pages 55,959-55,963.

>From the FEDERAL REGISTER (www.access.gpo.gov) and the FCC Web Site (www.fcc.gov).

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