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A monthly newsletter by Society of Broadcast Engineers Chapter 48

February 1999


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Contents


The January Meeting

Our first meeting of the year was held on Wednesday, January 13, 1999 at the National Digital Television Center. [Directions to NDTC] The guest speaker, Dennis Roundtree, was unable to attend, so the Industrial Power Systems backup power program has been moved to this month on Wednesday, February 17. Plan to join us at 12:00 noon for lunch in the NDTC cafeteria, with the business meeting and program to follow.

See you there!

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Never Miss a Meeting Again!

As a service to our memberships and readers, we've now added a meeting schedule to the Chapter 48 Web site. Just point your browser to: www.broadcast.net/~sbe48/sbe_schd.html and see what's coming up!

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SMPTE Adhoc Group on Inter-Facility Links

Microwave inter-facility links are critically important to nearly every broadcast station. Many of the present links have to be adapted to transmit new digital data in the near future, and choosing how to make this transition will have wide-ranging consequences. Yet no industry consensus exists on how to implement this aspect of the digital infrastructure transition.

Society of Motion Pictures and Television Engineers (SMPTE) is undertaking an effort to provide standards in this important area. The goal of this effort is to provide documented standards that assist manufacturers in providing equipment that broadcast engineers want to use, and to be able to provide this equipment in the shortest timeframe possible.

SMPTE urgently requests you to provide input regarding your requirements for microwave inter-facility links. Many manufacturers have already begun providing proprietary solutions for these links.

The following categories are provided for your convenience. Please elaborate as much as possible. Any input ranging from casual opinion to hard requirements will be considered.

VENDOR INTER-OPERABILITY

Air-interface standards define encoding, formatting, forward error correction, and modulation. This type of standard would provide inter-operability between different vendors equipment. Are air-interface standards a requirement?

LINK INTER-OPERABILITY

Traditionally, ENG and STL have used the same modulation technique. This enables easy IF-stage relay of the ENG signal via the transmitter's location. This also makes it possible to employ an ENG link as a backup STL. Is this a requirement?

DATA RATE

What data rates will you be employing for the different types of information? What is the data rate required for your ATSC and NTSC streams? What type of data (ATSC or NTSC) and data rate is required for digital ENG? What data rate is required for contribution-grade ATSC network feeds?

COMMON LINK INTERFACES

Inter-facility links may be implemented with microwave technologies, DS3 telco lines, metropolitan networks, etc. Is it necessary to have a common input/output electrical interface and bit-stream format for all of these different link implementations.

QUALITY OF SERVICE

How occasionally may an error-event occur? How long may the error-event last? In the case of a fatal link crash, what video/audio would you prefer as output from the receiver/decoder? What signaling is required to automate switching to a backup system? How long may the switch take?

AUXILIARY INFORMATION

Besides video and audio information, what other types of auxiliary information will you be passing through various types of microwave inter-facility links? Do these channels have full-duplex and/or real-time requirements?

MODULATION TECHNIQUES

Is it desirable to have different stations in the same geographic area use the same modulation techniques to reduce interference? Is a modulation technique requiring increased channel linearity acceptable?

Your immediate response is requested, and appreciated.

Thank you.

Best regards,
Jim Waschura
SMPTE Adhoc Group Facilitator

Please send response information to:

jim_waschura@synthesysresearch.com

Jim Waschura
SyntheSys Research, Inc.
3475-D Edison Way
Menlo Park, CA 94025
U.S.A.
Phone (650) 364-1853
Fax (650) 364-5716

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Job Postings

As a service to SBE/SMPTE membership, technology positions in the Rocky Mtn. region are posted at no charge. Please send your posting to:

Rome Chelsi
71610.777@compuserve.com

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Dan Roberts

Roberts Broadcast Services
Casper Wyoming

Dear friends, family & business associates:

After almost 21 years in Casper, Wyoming, I'm moving to Illinois at the end of the month. I've accepted a job with the Andrew Corporation in Orland Park, a Chicago suburb. This job opportunity came up quite suddenly. While visiting a friend who works for Andrew, over Thanksgiving, I mentioned that I might be interested in a change of scenery.

The next week, my friend, Kin Jones, called and asked me to fax him a resume. About a week later, the Andrew HR department called, wanting to know when I could fly out for an interview. Did that the Sunday before Christmas and lo and behold, they called me on January 5 with an offer I couldn't refuse.

I'll be flying all over the country selling Andrew transmission equipment to TV stations that are converting to the new HDTV (High Definition TV, or Digital TV). You've probably seen their red lightning bolt logo on microwave dishes as you've been driving down the road.

I am phasing out of the rep business as rapidly as is practical, but I'm not leaving my customers or companies that I represent holding the bag. I want them to know that I appreciate their business and loyalty over the years and will do what I can to prevent a gap in service.

I plan on maintaining this email address for at least a few more months. After the first of February, my business email address will be: dan.roberts@andrew.com . When I get settled, I'll pass on my snail mail address and any changes in personal email address.

Dan

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SBE Certification Dates

March 22, 1999 Deadline to apply to take an SBE certification exam on April 20, 1999 at the NAB Convention in Las Vegas.

April 30, 1999 Deadline to apply to take a local SBE certification test in the June 11 to 21, 1999 window.

September 30, 1999 Deadline to apply to take a local SBE Certification exam during the November 12 to 22, 1999 window.

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EAS Tech Tips

Clay Freinwald
Chapter 16, Seattle

Q. How do I build a low noise loop antenna for receiving AM signals at my station?

A. Give me a call at 206-726-7022 and I will send you an article from a 1975 broadcast magazine. It's a discussion and schematic for a tuned AM loop antenna, lower gain than a longwire, but much quieter (John Price, Entercom- Seattle) Note: John can also be reached via E-Mail at john.price@kiroradio.com .

Q. When the last RMT was received on my SAGE, the printout said something about a user time-out, and there was no printout indicating whether or not the RMT was actually re-transmitted. My station is in Auto mode. How do you check to see if the RMT was transmitted, and how to you print it out? (Tim Mauch, KBRO)

A. Go to alerts on the Main Menu, scroll down to Alert Log and there will be on the LCD the last 50 or so events the SAGE has stored. From there you can find what you need and verify the RMT was sent. ( Bob Walther, KARR)

Q. The clock in my TFT EAS unit drifts. What do I do about it?

A. On the back of your TFT-911 is J-108. Plug any wall cube into this jack and the clock will get its reference from the power line and not the microprocessor's crystal. (Chris/Ichabod Murray, LAECC, Lane County Oregon)

Q. We have experienced memory losses in our TFT-911, which may involve just one or two items in the setup, various items at different times. We have installed version .79 which is supposed to correct such problems, but I haven't seen that it does. (Cliff Grady, KIMA-TV, Yakima, and several others)

A. Contact TFT for assistance, they have yet another modification that involves adding some capacitors to the unit. (Pete Hoegg, KOAC)

TFT TROUBLES

It's been noted by several engineers that the TFT EAS-911 unit has a number of difficulties, some apparently are repaired with simple modifications, others require a call to the factory for assistance. With the TFT unit you are able to program a button to execute a function that takes a number of button stokes on a SAGE. The memory problem is discovered when you press the button and the expected event does not take place. Another, and a more complex, problem involves the way the TFT unit relays or auto-forwards what it has received. If you own a TFT - 911 it may well be worth the time to determine whether or not the unit is indeed functioning as you would like. From what I have been reading, Pete Hoegg, a Tech. at KOAC Radio and TV in Corvallis, Oregon, might be a good source of information. Some of these difficulties are being uncovered as we begin asking these EAS units to perform more complex and different tasks as our various EAS systems evolve. In many ways the SAGE and TFT products are quite different if not on their approach but their execution. Perhaps, it can be argued, the FCC should have been a bit more specific so that the products uilt by these manufacturers would have been a bit more alike. At this point the SAGE unit appears to hold the edge in terms of its ability to perform the required tasks. In this day and age of firmware driven hardware one would hope that these difficulties will result in field changes and upgrades to bring this equipment to the point that they perform their required tasks more alike. In the meantime, don't hesitate to contact the manufacturers and let them know what difficulties you are having.

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EAS News

Chapter 20

The FCC is urging broadcasters to come into 100% compliance with the Emergency Alert System. Following a recent survey of 653 broadcast stations, the Commission said that stations have improved compliance with EAS requirements, but must increase their efforts to do a better job.

One of the requirements we (on the receiving end of EAS tests) are having a problem with is 47 CFR Part 11.35 (it's in your EAS binder) which says "broadcast stations and subject cable systems must determine the cause of any failure to receive the required tests or activations specified in 11.61(a)(1)and(2). Appropriate entries must be made in the broadcast station log as specified in 73.1820 and 73.1840". Until now we haven't always been able to do that. When we receive an EAS test we log it and attach the printout tape to the entry and all is well. But when a test is NOT received was it sent (meaning we have a problem on the receive end), or was it for some reason not sent (requiring an entry per 11.35 above)?

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USA Digital Radio Inc.

COLUMBIA, MD. BUSINESS WIRE - Jan. 6, 1999

USA Digital Radio Inc., a privately-held technology company headquartered in Columbia, has announced that twelve of the nation's largest radio broadcasters, including nine of the top ten, along with Chase Capital Partners, a major investor in media and telecommunications, have taken equity positions in the company.

Owners now include CBS Corp., Chancellor Media Corp., Chase Capital Partners, Citadel Communications Corp., Clear Channel Communications, Cox Radio Inc., Cumulus Media Inc., Emmis Communications, Entercom Communications Corp., Gannett Co. Inc., Heftel Broadcasting Corp., Jacor Communications, Radio One Inc., and Sinclair Broadcast Group Inc.

"Digital Radio using In-band On-Channel technology heralds a new age in broadcasting," said Robert Struble, President and Chief Executive Officer of USA Digital Radio. "This support by the nation's largest radio broadcasters reiterates the strong industry commitment to a digital future, and expresses confidence in USA Digital Radio's In-Band On-Channel Digital Audio Broadcast (IBOC DAB) technology. Through these investors, USA Digital Radio has assembled an ownership group with coverage in 192 of the 267 Arbitron rated markets (including 49 of the top 50 markets) with access to 207 million listeners."

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SBE Contours

David Bower
Chapter 113

The test equipment and tools used in our early broadcasting duties bring back many pleasant memories. In the mid 1960s, such test equipment as the Tektronix 524AD oscilloscope and Simpson 260 VOM provided the paramount equipment for fixing and calibrating TV and radio station equipment. The Simpson meter did the trick for checking voltages inside equipment, and continuity and resistance checks on components. With its special high-voltage probe, you could check flyback transformers and other such high-voltage areas. The big Tektronix scope (and it was heavy) rested on a roll-about cart for transport. Although it was a single-trace scope, I used it to check camera chains, early quadruplex videotape recorders and other equipment. With its delayed-sweep capability, aligning the pulse widths on RCA TG2 sync generators was a breeze. With the big 10X probes clipped safely in place, the critical adjustments were made on the tube-based analog circuits, which always seemed to drift too much.

Another useful piece of equipment, the tube tester, had a special place in the shop (although we soon learned the prudence of checking tubes and NOT replacing them if they worked --- the rule "if it works, don't fix it"; may have originated with this realization).

Other basic tools included long nose pliers and wire cutters and strippers. The famous Weller 8000 series soldering gun was a critical tool for our repair work. This was before the wide use of plug-in circuit cards, and the broadcaster had to replace capacitors, resistors, transformers and other components while working through a maze of tangled wires and cabinet areas inside the broadcast equipment. You also had to be careful about getting shocked. Even equipment that was turned off held stored voltage in capacitors, just waiting to "reach out and bite" the careless technical person. This was before the era of tie wraps, and lacing cord was the preferred method to retain cable bundles. There was a wrong and correct way to tie and lace the cables; if you did it incorrectly, the cable bundle was not secure. Then there was the useful tube pullers for those hot vacuum tubes. Some just used a handkerchief--and worked quickly! For relays, we had a burnishing tool for cleaning those pesky pitted and dirty contacts. We usually kept our assemblage of tools in one of those "free" tube caddies we got from Bondurant Brothers, Roden or Chemcity (or Fistell's or Electronic Parts, etc.).

Things are different today with all the diagnostic aids for fixing electronic problems. And, of course, plug in circuit cards permit the broadcaster to work on the problem at the work bench. With plug in cards, it's very easy to change cards to isolate problems. Of course, spare cards can be shipped in by the manufacturer (if needed) to fix the anomaly. The use of high frequency dual trace oscilloscopes, low temperature soldering irons and the useful solder sucker play an important part in the repair initiative. And it takes "good eyes" and sometimes a magnifying glass for the microminiature circuitry!!

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Monthly HAMnet Brings SBE To Remote Areas

At 20:00 EST, 0000 GMT, on the second Sunday of each month, SBE Chapter 73 takes to 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.

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Society of Broadcast Engineers
Chapter 48

2950 South Birch Street
Denver, Colorado 80222


SBE Officers

Chairman
Eric Schultz (303)486-3694
schultz.eric@tci.com

Vice-Chairman
Fred Baumgartner (303) 486-3946
Baumgartner.Fred.M@tci.com

Secretary/Treasurer
Bill Harris (303) 756-4843
BHarris4@IX.netcom.com

Certification Chairman
Fred Baumgartner (303) 486-3946
Baumgartner.Fred.M@tci.com


SMPTE Officers

Chair
Fred Baumgartner (303) 486-3946
Baumgartner.Fred.M@tci.com

Secretary/Treasurer
Rick Craddock (719) 634-2844

Managers
Myron Olinger
Dick Phannenstiel
George Sollenberger

SMPTE Govenor (National Liason)
Rome Chelsi


Newsletter Committee

Bills Harris.......(303)756-4843 email: BHarris4@IX.netcom.com

Garneth M. Harris..(303)756-4843

Andre' Smith.......(303)556-3549 email: asmith@carbon.cudenver.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 & 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.