August 1998 Newsletter  
CMBE Signal Contour Graphic 
One of CMBE's better ways to show real signal contours. 
Come find out more about it at this month's meeting. . 

August 1998 

---Please Support Our Sustaining Members...--- 
Tower construction and maintenance for broadcast and communications. Contact Healy Moritz at 949-830-9800 

August Meeting 

CMBE Demos "Contours by Driving Around" 

Station sales reps come into the engineering department for three reasons. (1) They're new and lost, (2) they are looking for someone to work on their home VCR, and (3) to ask "Can they really pick us up in Temecula?" The standard answer to the latter question is, "No, not unless we've been added to cable recently." 

The standard FCC-rules based signal contour maps show that we get a perfectly fine grade B signal into Temecula. At 2000 ft. above the city, that's probably true. But at ground level, San Diego FM and TV outlets haven't a chance of serving Temecula's non-cable audience. It's that terrain problem. According to the FCC's old laws, the earth is a feature-less sphere. 

The numerous modern computer-generated models which do take into account terrain are based on the assumption that all is well with your antenna, and no other signal maladies exist. Besides, your competition's coverage counts, too, doesn't it? 

Enter Chip Morgan Broadcast Engineering (CMBE). According to our August meeting presenter, CMBE Sales Director Al Jason, "Now, for the first time in the history of broadcasting, you have the ability to get detailed maps of actual MEASURED signals of a broadcast station." 

"CMBE personnel will come to your city and using a highly advanced GPS high speed data acquisition (HSDA) system, measure and map literally thousands of points within your coverage areas. The GPS tracking and computer logging techniques record the signal strength of all the broadcast stations at once. CMBE will then transfer that actual measured data into graphic form that will clearly demonstrate the extent of the broadcast signal for each station in the market. 

"The results of the measurements are shown on full color maps and signal strength area analysis reports. The second line of text of each map shows the frequency measured as well as the date. Samples of these maps and reports can be found on our website at 

For a full explanation, join us at Jacor Broadcasting "Murphy Canyon," home of KOGO, KSDO and KPOP, August 19 at 7 p.m. with social hour and free food at 6 p.m. If all goes well, a studio tour will follow the presentation. 

If taking I-15: Go north to Clairemont Mesa Blvd and head west. The very first light across the freeway is Murphy Canyon. Make a left (south) and travel about 300 yards. 5050 is on the right side (west) of the street. 

If taking Highway 163: Go north until you reach Clairemont Mesa Blvd and head east. Continue east about one mile and when you start down the hill you will see Interstate 15 and Murphy Canyon is one light before the freeway. Make a right on Murphy Canyon (south) and travel about 300 yards. 5050 Murphy Canyon is on your right (west) side of the street. 

The entrance is in the middle of the building. The stations are upstairs. 

Philips Broadcast Digital Television Systems. Contact Lamont Dorrity, 310-966-2717. 

July Meeting 

Philips Talks Automation 

Members were treated with a short but useful chat on Philips Automation Systems. Sales rep. Lamont Dorrity and technical rep. Victor Acquino explained the ins and outs of their increasingly integrated systems solutions. John Rigg of KFMB said that he was impressed with the discussion about QNX, a speedy Philips superset of Unix which manages their systems. 

By the way, Philips joined our SBE chapter as sustaining member. Many thanks to Lamont Dorrity for his support, and for the pre-meeting treats. 

Richard Large showed off a great-looking KUSI. Included an interesting, modern news studio with short ceiling, diffused lighting, and six cameras! Thank you for hosting the meeting, Richard. 

Border DTV 

Mexico/US Agreement 
OK's San Diego, Short Spaces LA 

by Gary Stigall  

Whether or not you like the new border digital television allocation plan depends on who you are. As reported in the CGC Communicator , the FCC and Mexican SCT (Secretaria de Comunicaciones y Transportes) composed a Memorandum of Understanding regarding Digital TV along our border. 

On one hand, the document finally seals the DTV allocations given to the five San Diego stations, some of whom have ordered equipment on faith that all would be well with the allocation table announced this spring by the FCC. 

On the other hand, the agreement isn't kind to existing LA analog UHF outlets. Out of market viewing seems to be going the way of clear channel AM and adjacent market FM listening. 


Under terms of the memorandum, Tijuana would get for DTV development channels 23, 28, 29, 32, 46, 47, 58, and 59--all considered "close-spaced." Especially during summer tropospheric propagation conditions, 28, 46, and 58 all get decent signals into the mesas around San Diego. Interference criteria gave little protection to existing NTSC signals. 

The reason for all this close-spacing is practically too obvious to print: There's no other place to put these stations, what with every NTSC full-power broadcaster in the region given a second channel. Perhaps the negotiating parties felt that these channels would be built-up gradually enough that the interference might occur during only a couple of years, after which the U.S. analog stations would sign-off for good. 

Appendix 5, The Longley-Rice Methodology section, makes for interesting reading and gives some insight into the complex interference criteria that went into making the memo. The process is reminiscent of that which went into the original NTSC allocation table in the 1950's. Subjective viewing under controlled conditions led to the formulation of tables of logarithmic ratios between desired and undesired signals. As you might guess, signals received via analog AM are far less tolerant of co- and adjacent-channel interference than the digital counterparts, which have a good capture effect. 

Julio Brito, Chief Engineer for Ontario's KHSC (channel 46), says that the station does not consider any of San Diego County to be in their target market and they are resigned to accept the co-channel Tijuana station as a done deal. 

Pacific Radio for cable, connectors, racks, expendables, and MORE!

Non-Commercial FM vs. Channel 6 TV, with a Twist 

KSDS Agrees to 3 kW Tests 

by Gary Stigall  

Mary Woodworth, Station Manager of KSDS (FM, 88.3 MHz) says she has a reasonable want list: (1) Increase the station's power from 800 watts ERP to 22,000 watts circular polarization, and (2) be done with all the lost time and expense of negotiating with XETV over increasing the station's power. 

What Bob Anderson, Program Director of XETV Tijuana, wants is for KSDS to not increase interference to their non-cable viewers. 

The Mexican Secretaria de Comunicaciones y Transportes (SCT), the FCC's International Bureau, Cox Cable and Southwestern Cable, and the stations conducted negotiations via phone for a year. Neither station is having its way. 

What KSDS came away with is a Special Field Test Authority, still pending, to allow the station to run at 3 kW ERP vertical polarization from a 200-ft. tower at Mesa College for six months. They're hoping to start tests in mid-September. Hammett and Edison will run field interference studies for KSDS. Meanwhile, Bob Gonsett will evaluate interference for XETV. 

From Mary's perspective, a couple of items about the controversy don't add up. She doesn't understand why if XETV wants to reduce interference doesn't it increase its aural power. Currently, XETV runs with a 10:1 visual-to-aural power ratio, somewhat higher than is customary, or at least higher than would be ideal for fending off interference in this situation. 

And she doesn't understand why they must negotiate in the first place. "If we all just followed the FCC's rules, there wouldn't be a problem." She contends that there are no rules regulating FM power with respect to a foreign TV station. 

Bob Anderson of XETV maintains their station serves two countries. They have broadcast in English as an ABC affiliate, then independent, then as a Fox affiliate. They've had numerous U.S. public service programs on the air through the years. And, as the negotiations themselves prove, are recognized by both countries. 

He says they also serve Mexico as Tijuana's Fox affiliate. They frequently broadcast in Spanish on their SAP channel. And they constantly broadcast Mexican tourism promotion spots. 

Many stations in the U.S. alleviate their channel six/FM adjacency problems by co-locating transmitters to sooth the front-ends of nearby transmitters. Bob says that, unfortunately, this simply can't be worked out with KSDS and XETV. 

Because of their continuing negotiations, he declined to comment further. During the SFTA period, they will be looking for viewers, especially cable customers in Linda Vista and surrounding areas, who may experience problems due to cable shield leakage. 

San Diego's own RF broadcast line: Antennas, transmitters, exciters, translators, amplifiers, boosters and STL' s in stock in San Diego. (619) 239-8474 


from Portland Chapter 124 newsletter  

To: Owners of Tektronix Oscilloscopes Model Number TDS210 and TDS220 Subject: PRODUCT SAFETY RECALL, TDS210 and TDS220 

Tektronix has determined that certain incorrect use of our model TDS210 and TDS220 oscilloscopes may cause the ground connection to fail on these products, potentially exposing the user to risk of serious personal injury or death. As a result, Tektronix is voluntarily recalling these products. 

This recall applies to TDS210 and TDS220 products with serial numbers below the following: 

TDS210 - s/n below B049400 or C010880 TDS220 - s/n below B041060 or C011175 
Tektronix will modify your product(s) to remove this shock potential and return it to you free of charge. 

Even if your product appears to be functioning properly, you should not assume that it does not have an open ground connection. Consequently, immediately stop using the product. All TDS210 and TDS220 products should be returned to Tektronix at our expense for modification as soon as possible. 

You can call Tek at 800-835-9433 or go to 

Tenco Towers. Since 1978, serving broadcast and telecommunications communities in the west.(916) 638-8833 

SBE National News 

Fall Certification Deadline September 25 

SBE Certification provides recognition of your experience and knowledge in the field of broadcast engineering. It also shows others that you have made a serious commitment to stay current with new technology, regulations and practices. It's not too early to register to take an exam in November. For more information about SBE Certification, see your Chapter Certification Chair or contact Linda Godby-Emerick, Certification Director at the SBE National Office at (317) 253-1640 or 

SBE Local News 

Chapter 36 Gets Three New Sponsors 

by Gary Stigall  

These are good times for tower riggers. Of course, broadcast towers are a secondary business for them. Cellular towers are going up as fast as McDonald's hamburgers. Two tower companies have joined our chapter in order to give back to their "community." 

Healy Moritz, salesman for Tower Structures, is a fixture at SBE meetings here. He told me at a recent meeting that while they do a lot of cellular towers, they enjoy the unique challenges and pride of hoisting the big broadcast towers. "A lot of the newer tower riggers don't even know what a gin pole is," he said. They have a number of offices, including Bonita and Mission Viejo. Contact Healy at or by phone at 949-830-9800. 

Donald Tenn of Tenco Tower expressed interest in our chapter some time ago, and finally got around to becoming a sustaining member. They're out of Sacramento, but do a lot of business in Southern California. They've been around since 1978. Contact Donald at or 916-638-8833 

Philips has created good times for itself as well. They bought out the interest Bosch had in the old partnership BTS. They increased their product line, especially in anticipation of DTV integration. Their hardware works remarkably well together, and has a price point that no longer appears aimed at European subsidized broadcasters. Contact Lamont Dorrity at 310-966-2717. Get product information at the Philips Digital Broadcast Systems website. 

Thanks to you all for your support of Chapter 36. 

John Cuff Engineering,audio/video/broadcast systems engineering and integration, project management,and training.(858) 566-2207

Murphy's Corner 

(via Oscar Medina, KNSD) 

A young Engineer was leaving the office at 6 p.m. when he found the CEO standing in front of a shredder with a piece of paper in his hand. "Listen," said the CEO, "this is important, and my secretary has left. Can you make this thing work?" 

"Certainly," said the young Engineer. He turned the machine on, inserted the paper, and pressed the start button. 

"Excellent, excellent!" said the CEO as his paper disappeared inside the machine. "I just need one copy." 

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Edited by Gary Stigall. Updated 8-Aug-98.