MAY 2000
San Francisco
Roy Trumbull - Editor
Bill Dempster - Artist
Advertisers for this month's newsletter are:

Zack Electronics - (800) 998-3947
Advanced Marketing - Frank A. Santucci - (650) 365-3944
Belden - Steve Lampen - (415) 440-8393
Orban - Rick Sawyer - (360) 715-1913
MARCOM - Martin Jackson - (408) 768-8668
William F. Ruck, Jr. Broadcast Engineer - (415) 995-6969
RF Specialties of California - Bill Newbrough - (888) 737-7321
Hammett & Edison, Inc. - Dane E. Ericksen, P.E. - (707) 996-5200
LeBLANC - David A. Hill - (650) 574-4600
Gentner Communications - Kelly Hanning - (800) 879-9317
Improbable Missions Fource - Mike Schweizer - (888) 4-ISDN4U
Broadcast Systems - (800) 801-2623
Brill Electronics - Larry or Sam - (510) 834-5888
Kathrein (Scala Division) - Michael Wm. Bach - (541) 779-6500
Harris - John Briskie - (650) 593-1837
ADC Broadcast Systems Division - Russ Erickson - 877-440-7877

Our speaker will be Marty Acuff, Product Manager from ORBAN. He will have a presentation on the new Orban Optimod 8400 audio processor.

As usual, our luncheon will be at Sinbad's just south of the Ferry Building on the Embarcadero near the foot of Mission St. We meet at 11:30 and are seated at 12:30.

Shooter Legend Willie Kee
This is a note I got from Don Ford at KRON-TV about the medical condition of Willie Kee. Don's note was dated May 2nd. I don't know if Willie is still in the hospital. If you've ever been at a story site, Willie was the shooter dressed in black who wasn't at all shy about moving right in. - RT

Willie has been at St. Rose Hospital in Hayward for the last five weeks after suffering complications from diabetes. Doctors amputated part of his leg. He has some up days and down days according to his wife Jeannie. He is on Dialysis every other day.

Willie is truly a legend in California TV news. He started with film and only recently retired from KTVU. He has covered or been a part of nearly every major news event of the last thirty years. He has hosted the Chinese News Years Day parade for KTVU. He has won every major award from Emmys to Bay Area Press Photographer Awards; too many to list. He is a no bull kind of guy! He tells you in no uncertain terms when you have failed and is equally emotional when you succeed! I learned a great deal from this great man. He helped mold the way I shoot to this day. Willie Kee convinced me to come to the Bay Area.

If you would like to send him a card or letter, send it to his home:

Willie Kee
32979 Lake Wawasee St.
Fremont, Ca., 94555

NFL Game Coordinator Needed
The SBE and NFL are seeking a broadcast engineer to serve as the San Francisco 49er Game Day Frequency Coordinator. This is a voluntary position that involves the coordination of radio, TV, stadium, and NFL wireless users. Provided are two all access passes to each home game, a seat in the press box, a lap top computer, and a scanner.

Anyone interested should contact Paul Marks at KBLX Radio - (415-284-1029).

KBLX/KVTO/KVVN Radio has an opening for a maintenance engineer.

Duties include maintenance, repair, and installation of studio and transmission equipment, and assisting the chief engineer. Interested parties should contact Paul Marks at KBLX Radio (415-284-1029).

DTV Measurements
By Roy Trumbull

The single adjustment that will impact the DTV signal the most is the setting of the input path. The input cavity must tuned to the center of the channel and the driver to input cavity match must be set for minimum reflected power and 6 mHz bandwidth.

The bandwidth setting, usually reached by adjusting the tuner between the driver and input cavity, can be set to slightly over 6 mHz using a network analyzer. If a spectrum analyzer and tracking generator are used, the bandwidth needs to be wider and more drive will be required. This is due to the lower precision of the measurement versus doing it with a network analyzer.

The overall response can be set flat within a fraction of a dB. There will be a slight saddle at mid-channel. With no correction, the initial channel skirts will be about 30 dB. The indicated EVM (error vector magnitude) will be 9% to 12% and the S/N somewhat greater than 18 dB.

When nonlinear correction is applied, its chief benefit is that the skirts will increase to 40 dB. If you are using an IOT at a fraction of its power rating, you may be able to achieve 40 dB with no correction at all. The closer you operate to the tube's rating, the harder it is to achieve sharp skirts. The nonlinear correction also impacts the extent of the linear correction.

Assuming you are starting with a reasonably flat response, you will see very little change in the spectrum display when linear correction is applied. It's important that the RF sample used for measurements be taken from the output of the mask filter and after any combiners or other elements that might have losses.

The vector signal analyzer display will show improved eye and constellation patterns after the correction is done. Typical EVM readings will be lower than 4% and the S/N greater than 27 dB.

A proper nonlinear correction prior to doing the linear correction will lower the EVM and increase S/N numbers.

If you have an email address, please contact Warren Reese at Warren is in charge of our email list, which we use when we need to notify members when something has happened between newsletters.

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