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A monthly newsletter by Society of Broadcast Engineers Chapter 48

December 1997

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The November 1997 Meeting
Upcoming Meetings and Events
Shedding Light on Dimmers
SBE Files for EAS Mods
FCC Rulemakings
SBE Introduction to DTV RF Book Available
SBE/SMPTE Job Postings
Baltimore Radio Engineer Dies at 41

The November 1997 Meeting

Our November meeting was an event! It was our second annual technology seminar at the TCI National Digital Television Center, very well attended by members of SBE, SMPTE and SCTE in the region. Covering five hours including a catered lunch, it evoked these comments from three of the attendees:

Craig Roberts, TCI:

"Overflow in-studio audience .... Up-to-date information on the state of the technology .... Compression techniques have made a quantum advance in the last 12-18 months and some experts foresee 20:1 ratios within 3 years versus today's 12:1".

Fred Baumgartner, TCI:

All of North America was treated to six hours of commercial free, non copy- right techno-info-stuff courtesy the Denver SBE, SMPTE, and SCTE chapters, ...while crowds numbered nearly three digits, five speakers attacked the finer points of digital compression and processing for digital compression.

TCI's National Digital TV Center's Peter Douglas made opening remarks on how much things have changed comression-wise in the last year, and where they were likely to go. Next Level's whiz kid Lee Tram followed with an in-depth review of the basics and barriers to further compression efficiency.

Later that afternoon, Ron Beyers expanded on Lee's presentation with information from the test labs of TCI, and practical tales from the Headend In The Sky project, where through preprocessing, 144 channels are compressed onto 12 transponders.

Historical information was presented in an entertaining manner by Peter Symes of Tektronix, and Faroudja's Matt Miller wound up the technical side with insight into the marketing process.

The Keynote address was delivered by KUSA General manager Roger Ogden, who garnered the most laughs, and "hit the nail on the head."

A future program surrounding all thing AC-3 5.1 and digital audio was announced, dates to be set.

Rome Chelsi, IHS Communications Products:

"The Second Annual Technology seminar provided in depth information on the state of digital television and the migration to HDTV. Seminars of this caliber typically charge $1000 for attendance. The program was a tremendous value for the membership."

(Tapes of the Lee Tram/Ron Beyers sessions will be available shortly via the SBE Video Library (317-253-1640).)

During the lunch recess, elections were held for SBE Denver Chapter 48 officers for the coming year. Reelected to another term were Chairman Andre' Smith and Secretary/Treasurer Bill Harris. Succeeding Eric Schultz as Vice Chair/Programs is Fred Baumgartner. Many, many thanks to Eric for providing two years of great programs.

Be sure to join us on Wednesday, December 17, 1997 at 12:00 noon at the NDTC for our last meeting of the year when we see firsthand how the Global Positioning system can be used to precisely locate your towers!

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Upcoming Meetings and Events

Wednesday - January 14, 1998 Meeting only - KXKL Studios - 12:00 noon - 1560 Broadway, Suite 100

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SBE Chapter 113

At the last SBE meeting, I exchanged comments with others concerning whether someone accompanies them to remote transmitter sites as a safety precaution. Most replied that this was a "loner" job, and that the money (or support of management) was simply not there. This conversation followed a presentation on health and safety by Ms. Curtis, a representative of the American Red Cross. Although not technical, this proved to be a most interesting and informative meeting.

As broadcasters and those employed in telecommunications, we are sometimes exposed to a variety of hazards beyond the typical medical emergencies. Some of these hazards include RF shocks and burns, accidents in the vicinity of high towers, and dangers from transmitting equipment using high voltage. Although not an immediate medical emergency, we are exposed to a number of other hazards as well, such as solder burns and various toxic chemicals. Working alone only adds to all these, and working alone at a remote transmitter site, late at night, certainly magnifies the situation.

Perhaps we could find a way, through SBE, to increase awareness of this danger and communicate it to our employees. Money is always a concern, but perhaps making management more aware of the hazards in working alone can be improved.

There are several things we can do to decrease the danger of working alone:

Let someone know where you are and when you expect to return. Check in periodically by telephone or radio. Make sure someone knows when to expect to hear from you. Wear heavy boots and protective clothing when working at remote transmitter sites. Have a two-way radio or cell phone available (don't forget spare batteries).

Attending a first-aid class, as our speaker mentioned, is something we should all take to heart; and staying current is vital! The standards, such as having a first aid kit, fire extinguisher, safety glasses (I knew a CATV installer that lost an eye to a wiping guy wire that broke loose), flashlight, and other equipment, certainly are paramount. In cold weather, taking a portable heater and extra-heavy clothing along can be life saving.

The old standards in working around electronic equipment should always be observed:

A necktie or loose clothing can get caught in mechanisms. Keep one arm behind you when working on high voltage. Working around dangerous equipment when tired can really get you in trouble. Don't take unnecessary chances, such as defeating interlocks or forgetting to make sure circuits are not hot. The list could go on and on. Some of these rules come with training, others with experience. Common sense should always prevail. Our profession is certainly interesting and often rewarding; let's not forget that safety goes with the territory. Stay alert, and stay prepared.

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The Society of Broadcast Engineers offers a program of certification for broadcast engineers, ranging from the entry-level Broadcast Technologist to the 20+-years-of-experience-needed Professional Broadcast Engineer. A new certification program includes programs for Audio and Video Engineers which do not include any RF related questions.

February 20, 1998 Deadline to apply to take an SBE Certification test at NAB in Las Vegas on April 7th.

April 24, 1998 Deadline to apply to take an SBE Certification test during the June 12-22 local window.

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Shedding Light on Dimmers

After trying several different different commercial houselight dimmers in restaurant locations, the best I've seen for the money comes from Prescolite Controls, Carrollton, TX, 800-346-6377. Prescolite's dimmers are modular, with control modules and power modules. For under $1000, one can buy a control module and 2 PM-36 power modules. Each PM-36 handles 3600 watts, with 3 output legs, any one leg taking up to 2000 watts. The control module is about 7 or 8 inches wide and 5 or 6 inches tall. The power modules are the same width, and about 10 or 11 inches tall. Both are about 3 inches deep. Several power modules can be chained together for control by a single control module. It's a very compact system.

The phasing of the power inputs in dimmers is normally important. Roughly speaking, electronic dimmers control output by switching the power on and off. 60 times a second (or is it 120?). at some points in the phase. Therefore, most dimmers I've seen require all legs to be on the same phase, which means it's more difficult to balance the load between the 3 phases in a typical breaker panel. The individual Prescolite power modules can be powered by any phase, and they will "read" the phase, compare it to the controller's phase, and automatically adjust switching accordingly.

Prescolite makes a variety of control modules for different uses, and a variety of power modules for various voltage and fixture (e.g., incandescent and fluorescent) combinations.

The only problem with Prescolite dimmers that I've worked with has been the sensitivity of the triacs to a short circuit. Each power module has one triac. The failure of a triac normally does not mean a blackout. Instead, it means full power, no dimming. A bad triac normally will "short through." Short circuits will happen when electricians goof while hooking up the light fixtures during construction. Of course the electricians won't normally leave the circuit shorted, but when one tries to dim the lights for the first time, and they won't dim, that usually means that that is what has happened. On rare occasions a light bulb can also cause a very brief short circuit as it burns out, usually too brief to activate a circuit breaker. Replacing a triac in a Prescolite unit is trivial, a 5-minute job. No desoldering/soldering required. Just be sure to apply heat-sink compound (available at Radio Shack) to the new triac before installing it. It won't last long without it.

On the subject of electricity in general, I once changed the ballast on a fluorescent light fixture in a colleague's office, and when we started to smell smoke, I learned that fluorescents in office buildings are often powered by 270-volt circuits! So, if you're ever tempted to tap into a circuit in a ceiling, be forewarned.

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SBE Files For EAS Mods

SBE has filed a `Petition of Rulemaking' with the FCC requesting certain changes in the EAS system. Some of the highlights are: (1) an extension of the 15 minute time limit for rebroadcasting a monthly test, (2) a reduction in the minimum modulation requirement for EAS codes from 80% to 50% and a reduction in two-tone minimum modulation from 40% to 25%, and (3) a request that EAS decoders verify that national level messages are coded for the specific local area that the decoder is serving. This request came as a result of a false national alert that went out on a Chicago station and was relayed to a significant portion of the east coast.

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FCC Rulemakings

Tom Smith - Chapter 24

There is a list of minimum antenna heights and power levels that require routine environmental evaluation. For broadcasters, all broadcast transmitters are included, auxiliaries need to meet a minimum power and height limit. With amateur stations, the power limits vary according to frequency. The FCC also eased the rules for small transmitters in multi-transmitter sites. Transmitter plants producing 5% or more of the combined power density exposure limits are required to share the responsibility for correcting levels outside the exposure limits.

The FCC has amended its rules to allow certain modifications to a station's transmission facilities without first obtaining a construction permit. A station would only have to file an modification of license application after completing the modifications. The modifications that would only require one step applications include: the replacement of an antenna with an identical or similar antenna ( same number of bays ), adding vertical polarization signal up to same ERP as horizontal signal, use of former main transmitter site as an auxiliary (backup), and FM station power reduction (while maintaining required signal over city of license) or power increase up to maximum allowed for station's class of operation. Replacement of some directional antennas are covered by the one step application.

Construction permits are still required for sites near AM towers, change of tower coordinates or height, directional antennas not covered under one step applications, and power changes to meet ownership requirements. Moving a main studio outside of the city of license still requires an application before the move.

This action created a large number of rule changes, and stations should check the rules before making any changes without a construction permit. Some modifications may be covered under a one step application and a similar modification may still need a construction permit.

The rules become effective on December 1, 1997 and were published in the FEDERAL REGISTER on September 30, 1997.

The FCC has relaxed some of its rules concerning grandfathered short-spaced stations, which will allow these stations to increase power or make changes in transmitter location with greater ease. There are about 450 stations that were built before the 1964 transmitter separation requirements were created, and do not meet those standards. Because these stations are shortspaced to other stations, it has been difficult for these stations to make changes to their transmitter facilities. These rule changes may aid some of these stations to make needed changes to meet changing market conditions.

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SBE Introduction to DTV RF Book Available

SBE announces that pre-publication orders are now being accepted for the new "Introduction To DTV RF" publication. Written by Douglas W. Garlinger, CPBE, Director of Engineering for LeSea Broadcasting Corporation, this 100 page practical guide will be an invaluable tool to the Broadcast Engineer who needs to know the technical issues faced by all television stations facing the transition to DTV. Pre-publication orders will be accepted UNTIL DECEMBER 31, 1997 at a special price for SBE members of $39 and $49 for non-members. To order, or for information about this helpful resource, call the SBE National Office at (317) 253-1640 or fax your request to SBE at (317) 253-0418. Payment by credit card or check must accompany orders. Send mail orders to: DTV RF, Society of Broadcast Engineers, 8445 Keystone Crossing, Suite 140, Indianapolis, IN 46240.

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SBE/SMPTE Job Postings

As a service to Rocky Mountain regional SBE/SMPTE members, technical and production oriented job postings are published at no charge.

Telecommunications / Electronic Specialist

This position is located in Educational Support Services of the University of Colorado Health Sciences Center. The postion assists faculty, staff and students in utilization of TV and electronic media. The position will construct, modify, service and/or repair and operate audio and video systems. The position requires 3 years of technical experience repairing, performaing maintenance, installing, modifying, calibrating, certifying or fabricating media equipment. Starting salary is $2584/month.

To apply, applicant must submit a UCHSC application, resumes may ba attached, to: UCHSC Human Resources, Office Annex Builing Room IC51, 4200 E. (th Avenue, Dever, CO. no later than December 30, 1997.

UCHSC is equal opportunity and affirmative action.

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Baltimore Radio Engineer Dies at 41

The following obituary and tribute to Dwight Weller was submitted by Rick Barnes, Secretary of Baltimore SBE Chapter 46.

If you walk into just about any radio station in Baltimore and mention the name Dwight Weller, chances are somebody will remember a time when he came in on a cold rainy night to repair a transmitter or fix some studio equipment. The name Dwight Weller was synonymous with radio broadcasting in Baltimore. He was a broadcast engineer's engineer. On October 24th, at the age of 41, the cancer in his body took its toll and Dwight passed away.

The list of radio stations that he was affiliated with includes, among others, WFBR, WLIF, WCBM, WBAL, WWLG, WASA, WITH, WERQ, WWIN AM & FM and WOLB. This year, he worked on the radio broadcast team for the Ravens football team. Dwight also ran his own company, Weller A/V, which provided broadcast equipment to radio stations nationwide.

For a number of years, Dwight worked in the Baltimore Field Office of the Federal Communications Commission. One of Dwight's notable achievements was serving as the Chairman of the Baltimore Chapter of the Society of Broadcast Engineers. He held this annually elected position for more than eight years. Dwight was also single-handedly responsible for editing and publishing the chapter's monthly newsletter. Dwight was a mentor and teacher for young radio engineers coming up through the ranks.

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Society of Broadcast Engineers
Chapter 48

2950 South Birch Street
Denver, Colorado 80222

SBE Officers

Andre' Smith (303) 871-4204

Fred Baumgartner (303) 486-3946

Bill Harris (303) 756-4843

Certification Chairman
Fred Baumgartner (303) 486-3946

SMPTE Officers

Fred Baumgartner (303) 486-3946

Rick Craddock (719) 634-2844

Myron Olinger
Dick Phannenstiel
George Sollenberger

SMPTE Govenor (National Liason)
Rome Chelsi

Newsletter Committee

Bill Harris.......(303)756-4843 email:
Garneth M. Harris..(303)756-4843
Andre' Smith.......(303)871-4204 email:

Views expressed herein do not necessarily reflect the official positions of the Society, its officers, or its members. We regret, but are not liable for, any omissions or errors. The Denver SBE & SMPTE Newsletter is published approximately twelve times per year. It is prepared with a combination of text and graphic data. Submission deadline is 10 days before the last day of each month. Other SBE chapters are permitted to use excerpts if attributed to the original authors, sources, and/or the Denver SBE Newsletter.