A monthly newsletter by Society of Broadcast Engineers Chapter 48

April 1997


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Contents

The March Meeting
Chapter 48's Next Meeting
Schedule of Upcoming Meetings and Events
SBE Chapter 40 Newsletter
Nominations for SBE Annual Awards Open
Membership Renewal Time is Here
SBE Membership Drive
SBE Web Page
ITC Manufacturing Sale
Year 2000 Computer Fix
Basic Stamps
Batteries Article
Amateur Radio News
NTSC Handback Delay Debated
Etc.

 

The March Meeting

Members of Chapter 48 met once again at TCI's National Digital Television Center on Wednesday, March 19, 1997. During lunch in the facility's cafeteria, discussion centered around the topic of HDTV. Members discussed issues of HDTV frequencies allotments and bandwidth requirements. Most everyone agreed that they wouldn't be very willing to pay five thousand dollars for a new TV once NDTC is phased out entirely. Members also talked about the upcoming NAB convention and the best places to stay while in Las Vegas.

After lunch, the meeting moved upstairs to the conference room where the meeting was officially called to order by chapter chairman, Andre' Smith. Andre' brought up old chapter business by informing us that he had contacted Rome Chelsi from S.M.P.T.E. and Shelly Slater from S.C.T.E. to coordinate a meeting to discuss the frequency coordination issues that were raised by John Hellyer at chapter 48's February meeting. Information regarding a future meeting on the subject of frequency coordination will be forthcoming. Jack McKain from KWGN mentioned that he had been receiving several calls from people who wanted to 'borrow' some of his full-time RPU frequencies and that coordination for the Oklahoma bombing trial had become a major concern. Jack has also been working closely with Rebecca Willman from the FCC's Denver office to coordinate a state-wide EAS plan. Rebecca will be making the plan available for the chapter's newsletter and web site.

Nikki Shears, also with the FCC in Denver, told everyone that April 19th, 1997 is Internet Wiring Day. The FCC and other volunteers are working to get many of the schools in our state connected to the Internet. If you have old (or new) computer equipment that can be donated or if you would like to offer your talents, contact Jay Hokanson at the FCC at (303) 969-6498.

Fred Baumgartner, Chapter 48's certification officer, mentioned that he has received information on the SBE's two new certification levels. The new certifications are Certified Engineer/Video (CEV) and Certified Engineer/Audio (CEA). The CEV and CEA were developed for engineers who do not work with RF transmission. If you are interested in having people from you facility certified or becoming certified yourself, contact Fred at TCI, (303) 486-3946.

After chapter business was concluded, Troy Jensen of RPG (Reflection Phase Grating) gave an informative presentation on acoustics for broadcast studios. The presentation began with a review of the basic properties of sound; what sound actually is, how it is produced and the concepts of wavelength, velocity, frequency and amplitude. Troy then discussed the properties of building materials; how they absorb sound by converting acoustic energy into heat, and how they reflect and diffuse sound. Troy then covered the acoustic goals for a recording environment and the criteria for a proper listening room. Sound isolation, room geometry, speaker placement and reflection control all play important rolls in acoustic performance. Next, Troy discussed some interesting methods for finding the best spots to place absorptive and diffusive materials. RPG emphasizes that by placing acoustic materials in very specific areas, lesser amounts of the materials are needed, and acoustic performance is optimized. Thanks again to Troy Jensen of RPG and to Steve Johnson of HP Marketing for their informative presentation.

Next month's meeting will be held on Wednesday, April 16th at the Coco's restaurant, located at the intersection of Parker and Havana roads, in Aurora. Meeting time will be 12:00 noon. Be prepared to relate stories of the interesting things you encounter at this year's NAB convention.

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Chapter 48's Next Meeting...

... will be held on Wednesday, April 16, 1997 starting at the noon hour. Meeting location will be the Coco's restaurant, just southeast of the Parker and Havana reoads intersection.

As this date will be the first Wednesday after the NAB convention, it will provide a forum for individuals to discuss thier impressions of the convention. Come bring your stories.

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Schedule of Upcoming Meetings and Events

Unless noted, all meetings will begin at 12:00 noon for lunch. Programs follow a brief business meeting, where listed.

Wednesday - April 16th (during NAB), luncheon only - Coco's Restaurant at South Havana and Parker Road.

Wednesday - May 21st - National Digital Television Center at 4100 East Dry Creek Road - Program: New digital audio technology (Consoles & Routers) Rick Strage, RCS Inc. - Digital Console Division

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SBE Chapter 40 Newsletter

Roy Trumbull - Editor

LAUGHS, LUCK...AND LUCY... That's the title of a memoir by writer Jess Oppenheimer who created television's most memorable sitcom. The book was published by Syracuse University Press and recently released. I'm going to pick up a copy as soon as the stores have it.

I saw an excerpt from it in a review where the author proves what we all know. You can't make up anything funnier than what really goes on in our industry. A case in point being a tale from KFRC. Back in 1934, Jess was hanging out there looking for a break.

It seems that then station manager Harrison Holliway was getting set to interview a railroad engineer for the very popular show "Blue Monday Jamboree". In a meeting with the subject the day before they got to talking about train whistles and what they meant. It turned out there was a real language to the short and long whistles which was known to the practitioners. This particular engineer had a special sequence he would blow starting 4 miles out of town that told his wife that it was his train heading into the station and that he would soon be home. She'd have his supper waiting for him.

Harrison realized the story was good but that it really needed the train whistle to work. The sound effects man wasn't able to duplicate the real thing. The subject volunteered as how they had some extra whistles in the shop and that one could be brought over but it would need air pressure to operate. They had air compressors.

No one thought to ask the question that if you could hear one of these whistles from 4 miles out of town, how loud was it? But it's amazing that once something like this is set into motion how it tends to proceed. Before any voice of reason could come to bear on the advisability of bringing a full sized train whistle into a radio studio, there it was in all its huge splendor being offloaded from a flat bed truck and wheeled in to be placed 30 feet in front of a audience of 100 people.

The arrival of the whistle took place on the day of the broadcast and it cleared the hallway ceiling with just 6 inches to spare. The air hoses were connected just prior to the broadcast and there was no time to check it out.

The interview commenced with the engineer holding onto a rope which operated the whistle. When the topic became the whistle and the demonstration was required, the first blast blew all the windows in the studio out onto Van Ness Avenue and generally was not a healthy experience for those in attendance nor for the transmitter which was off the air for some time. In his account, Jess says two weeks. I wonder if we have any survivors of the incident who could verify the extent of damages?

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NOMINATIONS FOR SBE ANNUAL AWARDS OPEN

SBE Awards Committee Chairman, Ray Benedict, CPBE has announced the opening of nominations for the 1996 SBE Awards Program. Nominations are solicited in a number of individual and chapter categories. Winners will be recognized during the 1997 SBE National Meeting in Syracuse, New York, September 26 at the SBE Annual Awards Dinner. Use the form found in the February/March issue of the SBE SIGNAL to nominate worthy candidates and achievements. There is no limit to the number of nominations you may submit.

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Membership Renewal Time Is Here

SBE Membership renewals were mailed in February to all Regular, Associate and Student members. Be sure to return your renewal form with your payment by April 1. Regular and Associate dues remain at $55 for the sixth year while Student Dues are $15. If you did not receive your membership renewal information in the mail, call the SBE National Office at (317) 253-1640 or e- mail Teresa Wallman at twallman@sbe.org , as soon as possible.

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SBE Membership Drive

SBE has also added a new twist to this year's membership drive. Two chapters that recruit the largest percentage of new members, based on total chapter membership, will win a presentation at a chapter meeting led by a nationally recognized broadcast engineering industry speaker. There will be one winning chapter in two categories: those with under 40 members and those with 40 or more members, as of February 28, 1997. Both portions of the membership drive began on March 1 and will continue through May 31, 1997. Each member has received a flyer and a membership application in the mail. These materials can be duplicated if you need more. To qualify for the drawing, new members must be Regular, Associate or Sustaining Member candidates. New Student memberships do not qualify for the drawing.

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SBE Web Page

The SBE Home Page recorded its 50,000th access in late February. That computes to an average of more than 2400 "hits" per month since the page was initiated in July of 1995. Join the crowd: http://www.sbe.org!

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ITC Manufacturing Sale

ITC has sold the manufacturing, sales, and service rights to its analog cart machines to Diagnostic/ Retrieval Systems, Inc. a New Jersey-based company which specializes in information storage/retrieval technology. Cart operations remain based in Bloomington, IL but the phone number has changed: 309/662-1941.

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Year 2000 Computer Fix

For those of you concerned about computer software problems in the year 2000 and beyond, there is a web site that may be of assistance. Click on www.rightime.com for a free software patch that will allow your PC bios to correctly interpret the date after 1/1/2000. Of course individual software packages may still need further patches to be usable after the "temporal anomaly" of the turn of the century.

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Basic Stamps

Greg Abel -Chapter 20

No, you do not use them for postage. The Basic Stamp is a hybrid PIC (peripheral Interface Controller) the size of a 24 pin DIP module by Parallax, Inc. It has 16 I/O lines, 50K baud serial I/O, 500 instructions at 4000 per second, 2K byte EEPROM (Electrical Erasable prom), basic interpreter and voltage regulator ($50). You can purchase a carrier board that provides all the connections to the module including the standard 9-pin RS-232 sub-d connector.

Programming is simple. Using Parallax's programming kit ($100 one time cost) and a PC allows you to edit the asic program and down load it to the Stamp for execution. The editor also provides information such as memory usage and syntax errors. Once the program is loaded and running it will remain in the EEPROM even if power is lost. Now you might be thinking, what can this do? Well, it cna produce DTMF tones, PWM, serial communication control, plus many other things that cannot all be covered here. One application that I use it for, is controlling a Utah Scientific serial router. I took a Grass Valley 10XL panel, and wired it to 5 of the 16 I/O lines on the Stamp. A basic program in the Stamp changes the BCD output of the 10XL panel to serial for the router and uses the serial refresh data from the router to tell the 10 XL panel to light the switch tallies. The applications are endless, maybe EAS remote control? I introduced this to Victor Pasquarelli, Chief Engineer of KDKA radio. Vic is programming an LCD panel to display EAS data at remote locations. He is also using it to control tape decks using Visual Basic and the Stamp along with a switching matrix. I had to laugh because the day Vic got the Stamp, he had it up and running, pulsing a voltmeter for test purposes. It is very important to document connections and the program so that anybody could modify the design. Since learning Basic is simple, just about anyone can understand the design in case the original author moves on. This helps to ease the concern on customized designs. There are many forums on the internet along with news groups all pertaining to the Stamp. Also a very interesting magazine called "Nuts and Volts" has one article per month on Stamp applications. Two pertinent web sites: Nuts and Volts Magazine www.nutsvolts.com and Parallax Inc. at www.parallaxinc.com Please note that there are many PIC manufacturers also. PIC programming goes to even a deeper level for applications requiring speed in execution.

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Batteries Article

Larry Bonnell
Instructor of Electronics; El Paso Community College

There are basically five types of batteries; Carbon-zinc, Alkaline, Mercury, NiCad, and Lead-acid.

CARBON ZINC

The carbon-zinc cell is 1.5 volts, very inexpensive, and generally has a short life. It becomes noticeably weaker with each use, discharging much like voltage on a capacitor, quickly at first then more slowly. This is a primary cell and is NOT rechargeable.

ALKALINE

The alkaline cell is 1.5 volts, costs two or three times the price of a carbon cell, but last two or three times longer. Its discharge curve is gradual at first then more quickly after a time. There is also a rechargeable version, but they are not nearly as efficient as the NiCad cells.

MERCURY

The mercury battery can be either 1.35 or 1.4 volts depending on its specific chemical make-up. Its discharge curve isn't a curve at all, it works well until it has nearly discharged, then it will suddenly go dead. Interestingly, it will last longer with light usage that it will sitting on a shelf. A variation is the lithium battery which is 3 volts, the same characteristic discharge, but has a life approaching 10 years. The latest technology is rechargeable lithium.

NICAD

The nickel-cadmium battery is 1.2 volts per cell, high current, and rechargeable thousands of times. The discharge curve has a small rise at full charge and is relatively flat for the most part, then curves downward just before discharge. For longest life, the NiCad should be nearly discharged before recharging. Charging should be according to specification, a certain current for a certain time. Deviation from this discharge/charging process may cause the cell to retain a "memory"; and consequently a shorter life.

To avert this, first discharge the battery completely. Probably the best way to discharge a battery is to rig it to an indicator lamp and leave it alone until the lamp goes out. Next, apply short surge of current, about an ampere for a second or so. Then check for battery voltage, and if there is near normal voltage, charge the battery normally. If the voltage did not come up to near normal, the battery needs to be replaced.

LEAD-ACID

The lead-acid battery is 2.2 volts per cell and is the type used in automobiles. It is very high current and has a discharge curve identical to the NiCad type. The discharge curve has a small rise a full charge and is relatively flat for the most part, then curves downward just before discharge. The electrolyte is dilute sulfuric acid and only distilled or deionized water should be added if the electrolyte level is low. The lead acid battery is not maintenance free even if it says so on the battery. These batteries require periodic maintenance. Charging rates should not exceed about 10 amperes or the plates may warp and cause shorting. The lead-acid battery can deliver hundreds of amperes for a short period of time.

GEL CELL

A variation on the lead-acid type is the gel cell. The advantage being that it can be used in various positions and is sealed. They are used in children's riding toys and security systems. The gel cell is a maintenance free version of the lead acid battery and consequently doesn't last as long as its wet cell counterpart.

ANALYSIS

Rapid discharge of a battery will cause it to overheat, but rapid charging may cause a battery to explode. A short circuit can cause any high-current battery to rupture. All batteries are caustic, BE CAREFUL!!!

Copyright: 1996 Larry Bonnell

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Amateur Radio News

Tom Weeden, WJ9H

The "Little LEO" (Low-Earth-Orbiting) satellite industry's efforts to secure spectrum space in the 2-meter ham band have narrowed their focus to the 146- 148 MHz segment. The industry also appears to be attempting to reposition itself as a potential emergency communication adjunct to ham radio. Little LEOs would use satellites to provide position location and two-way data- messaging services to potential customers around the world.

The launch of amateur radio's most sophisticated satellite to date, "Phase 3D," has been postponed until early July. The European Space Agency has announced a launch delay for Ariane 502, the rocket that is supposed to carry Phase 3D. The amateur satellite corporation, AMSAT, is still assembling the satellite in Orlando.

Another space shuttle mission will also involve amateur radio. STS-83, scheduled to launch April 3, will carry three hams. Eighteen schools, including institutions in the People's Republic of China and on Okinawa, have been scheduled for radio contacts during the mission.

The FCC has proposed revising its Part 5 Experimental Rules to permit longer license terms and to permit the use of the 2402-2450 MHz and 10.0-10.5 GHz bands for experimental services. These two bands would be shared with the amateur service. The experimental license is for students experimenting with radio technologies in colleges, universities, and elsewhere.

The Solar Cycle 23 Project, carried out by the NOAA Space Environment Center with the support of the NASA Office of Space Science, predicts big things for the upcoming solar cycle. Cycle 23 should peak in early 2000, annual average geomagnetic levels will be among the highest in the 128-year record, and the probability of severe geomagnetic storms "will be the greatest during an extended period lasting from 1999 through 2005." The failure of Telstar 401, thought to be due to solar activity, occurred near the solar cycle minimum.

(Excerpts from February 1997 Badger State Smoke Signals and QST Magazine)

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NTSC HANDBACK DELAY DEBATED

Chapter 28

Broadcasters will get an additional year in which to switch to digital under a revised Clinton administration digital TV transition plan. National Telecommunications and Information Administration (NTIA) head Larry Irving testified before the House Telecommunications Subcommittee in mid-February that broadcasters would have until 2006--not 2005 as earlier proposed--to hand back the spectrum used for analog TV. But the analog spectrum would still be auctioned in 2002, as in the original plan, to raise an estimated $14.8 billion.

(From Broadcasting & Cable, 2/17/97)

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Newsletter Committee

Bill Harris.......(303)756-4843 email: BHarris4@IX.netcom.com
Garneth M. Harris..(303)756-4843
Andre' Smith.......(303)871-4204 email: ansmith@du.edu

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 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.