All posts by Gary Stigall

Meetings

October 2007 Meeting – Telos Brings the ZIP

Among the most memorable San Diego SBE meetings were in the late 1980s when Steve Church of Telos Systems introduced us to the DSP phone hybrid, and later when he brought the Zephyr ISDN transceiver and described its new underlying MPEG compression scheme. At this month’s meeting, Michael Uhl of Telos-Systems shows off the Zephyr IP, or Z/IP.

The Zephyr IP uses wired or wireless internet links to pass audio from location to location, the theory being that IP connections are now easier to find than the ISDN lines required for the previous Zephyr models. Inside the box, the Session Initiation Protocol (SIO) assures that the best codec for the conditions presented get used so that the connection uses minimum bandwidth for highest fidelity with lowest latency. The Z/IP was designed to work with existing boxes, as well.

Mike will also bring a sample Axia audio router and Omnia audio processor and answer questions about any or all of those sister products.

This month’s noon meeting takes place at Lincoln Financial Media, home to KSON, KBZT, and KIFM. Members and guests are welcome to join us October 17 at 12:00 PM on the 7th floor at 1615 Murray Canyon Road. Lunch is provided by Telos. Park on the street outside the tall building and proceed up the elevator.

Best of Site, Local News

Normal Town – Setting Audio Levels for San Diego TV

If Bob Vaillancourt, Engineering Manager for local NBCU O&O KNSD has anything to say about it, San Diego’s TV audio is about to improve. In spite of great new pictures with high definition broadcast TV, one of the lingering complaints about the technology is the audio. It’s all over the place. Compressed commercials can blow out the audience after a soft dramatic scene. Local material doesn’t always match network material in an automated master control. And different local stations can have very different levels as viewers surf through channels.

Bob said he had recently spoken with NBCU’s Advanced Technology guru, Jim Starzynski, who laid out a plan to address loudness using the Dolby dialnorm setting that is a part of the Advanced Television Systems (ATSC) standard. That plan starts with each of the ten network owned and operated stations, but he said it needs to spread to the other digital stations in each market, and ultimately to all ATSC stations.

Dolby dialnorm is part of the specification written into ATSC that helps normalize audio levels based on metadata that rides along with the audio. Normalization, unlike compression or limiting, doesn’t change the dynamic range—only the level of audio. Researchers learned that people who watch TV like to set their volume levels based on dialog instead of music or background. Dialog normalization, or dialnorm, attempts to automatically adjust dialog levels based on the standard of the source. Without dialnorm, Dolby interprets the dialog amplitude as being averaged around -31 dBFS. With a Fox dialnorm setting of -25, they are commanding the end viewer’s Dolby decoder to release its audio to the amplifier with a 6 dB attenuation. With a local setting of -23, the decoder attenuates the local material 8 dB.

How do you derive those settings? That’s where Bob comes in. NBCU bought for KNSD a Dolby LM-100 Loudness Meter that specifically reads loudness with respect to digital full scale only during dialog. Bob sampled all the San Diego area English language DTV stations over a two-week period in early July. He took readings during primetime, fringe, daytime, and even overnight. He put the readings into a large spreadsheet to share with local broadcasters.

The results are interesting. First, all the stations in the market except KNSD and KPBS had their dialnorm settings on their Dolby encoders at the Tandberg default of -27. KPBS had theirs at -31–the setting that signals Dolby decoders not to normalize levels. Bob had set KNSD’s dialnorm at -22 to begin with, then adjusted it during the week to -23. He recommends XETV FOX6 set its dialnorm to -23 based on an average of 43 loudness readings ranging from -20 to -29. Readings at KPBS swung the most, as you might expect of a public station with widely varying content and no dialnorm action. Readings at KUSI were the most consistent, as you might expect of an independent station heavy with news and talk content.

XETV has adjusted its dialnorm to -25 based on a recommendation from Fox Network, though we intend to adjust that figure after analyzing it more. Jim DeFilippis, Fox VP of Engineering, said that they will be working with affiliate stations and the other networks to implement dialnorm. FOX6 will soon be applying normalization to all local recorded content.

Bob says that they now have the Dolby Loudness Meter at their ingest station where operators use it to help them set levels. He is looking forward to working with all local engineering crews to get their dialnorm settings programmed. Once this is done, viewers should hear more consistent loudness when switching between stations as well as when the stations switch between local and network content.

You can learn more about dialnorm in this Broadcast Engineering magazine article.

 

Meetings

August 2007 – Beach Picnic

Chapter 36 hosts a picnic at Crown Point in Pacific Beach Friday afternoon, August 17, from 5 PM till closing. We’ll provide an entrée, sides, and sodas. You bring some wood for a fire and any other beverages you’d like. Also bring your family—spouses and kids love to talk about T1 lines and failed transmitters.

Alcohol is allowed at Crown Point Park, but no glass containers are allowed. Entrance gates close at 10 PM.

Contact Gary Stigall or Eric Schecter for exact location and to help us plan sufficient food and drink.

Join us in making this a fun tradition in San Diego. Members, guests, and families welcome, but please reserve your spot.

 

Local News

KSDS Now Burning at High Power

KSDS (FM) started transmitting at its newly permitted 22 kW ERP as of late June. The station, managed by City College and transmitting on 88.3 MHz from a tower at Mesa College in Linda Vista, should now cover much of San Diego County with their full-time jazz format. Now they’re on par with their commercial brethren, and with neighboring KKJZ in Long Beach at adjacent channel 88.1. That’s a long way from the 830 watt powerhouse they were before May 2000.

KSDS installed a new Shively 5-element half-wavelength spaced array at 160-feet above ground. The antenna has a cardioid pattern with shallow (60%) null to the southeast.

The radiation will remain vertically-polarized to provide some protection to nearby circular-polarized XETV channel 6 in Tijuana. While most closely-spaced channel 6 – NCE-FM combinations around the U.S. have co-located to reduce interference, such an arrangement wasn’t possible due to the international boundary here. The FCC only recently allowed the increase in power, saying that international treaties don’t specifically deal with FM-to-TV adjacent channel conflicts.

Larry Quick, CE at KSDS, says they have set-up an email address and phone number to deal with viewer complaints. Both KSDS and XETV are hoping that with the high adoption of cable, satellite, and digital TV, the interference problem will be minimal.

Disclosure: The author is employed by Bay City Television, U.S. operators of XETV Fox 6, a subsidiary of Televisa and party in recent interference FCC filings involving XETV and KSDS.

Best of Site, Commentary

SBE36.ORG Ten Years Later

In July of 1997, Dave Biondi in Texas offered free webhosting for SBE chapters wanting to create a site. Having wanted to learn HTML and the various allied technologies, I went for it. Netscape’s browser came with a decent HTML editor, so with a Sams book in my lap, I created the first chapter web page. We registered an independent website a couple of years later, still using the Texan.net servers. That first web page still exists, though the logo has been updated and the site is now hosted in San Diego at Aplus.net.

The idea of informing the San Diego broadcast engineer about the SBE chapter and local industry news seemed obvious. At that time, Ron Foo and John Barcroft at KGB were working hard publishing the monthly SBE chapter print newsletter. I wanted more local content and eventually to help relieve them of some of the laborious processes of composing, copying, folding, stapling, stamping, and addressing. Some chapters, like Portland, do such a consistently good job of covering local events that it just seemed possible to do that here. And the intended audience was supposedly wired, so wouldn’t it also be possible to set-up web and e-mail distribution?

In 1997, I had a brand new screaming 160 MHz Macintosh Performa 6360 and quickly bought the BBEdit text editor and some cheap graphics software. With some Apple Quicktime macro programming, I could create a webpage from plain text paragraphs in seconds. I created web banner ads for our sponsors and at one time had 24 in circulation, some artistically pleasant, others not so much.

The only problem with this technique is that it creates static web pages. If your design later changes or you get new sponsors and need different banners to rotate, you have to re-render the HTML. I looked around for a more dynamic web page publishing technique, but I couldn’t find anything well enough documented that I could learn it in what little spare time I had. I did learn and implement Cascading Style Sheets, or CSS, which is a cool way to write a central design structure with a single text document.

In 2001, when I gave the job a rest for a year, webmaster Tim Toole won the SBE Chapter Website of the Year award.

In 2004, I created a potentially commercial site called Benx.us (Broadcast Engineers’ News & eXchange), but it really demanded collaboration and everyone else had their own gig going and didn’t want to combine efforts. Hackers seemed to enjoy exploiting the PHP forum vulnerabilities so that I had to reload the site daily for a while. With respect to the forum, people had different interpretations about freedom of speech. I took it down after a few months.

In 2005, I discovered the underworld of open source content management systems (CMS). These systems, depending on the increasingly popular open source PHP web task language and SQL database, automate all the dynamic web pages. All you have to do is customize a template and install the desired working modules. If you are seeing this in the summer of 2007, you are looking at the Mambo CMS with a customized JW Tribute template. Look at this site for a peek at what it looks like elsewhere.

I haven’t seen much discussion about this, but that pile of code makes the site seem vulnerable. First, many of the modules they distribute don’t work. That’s probably due to the classic mistake that amateur programmers make in writing for their particular circumstance and not to the greater design framework. Often they just lose interest while chasing all the bugs. We tried to use Mambo for an intranet at work, but customizing it got us into a mire of spaghetti code that we didn’t have the time to devote to–time is money. All that PHP code and that one, big, increasingly vulnerable database make me quite afraid that one day the site will be broken and I won’t be able to reconstruct it. Yes, I back it up, but what happens when the host updates PHP and MySQL and some of the code stops working? Meanwhile, the webpages from before 2005 just sit there as little text files, ready for viewing–simple, like an old car.

So for SBE36 version 3, I’m looking for a simple implementation of PHP and CSS, from which I can make a site from a structure of stored HTML insert text files. Sort of like the original site, but with dynamic style, banners, and menus.

Ideally, there should be one SBE supersite with virtual chapter sites built-in. You contribute articles and checkoff boxes as to where they should be read. But that’s not in the spirit of the ever independent web.

Why do all this work?

I thought about this question and at first came up with noble answers about informed citizens in a democracy and all that, but it’s more primal, really. Writers are simply compelled to tell the stories of their time. You ask Bob Gonsett of Fallbrook, Clay Freinwald of Seattle or Kent Randles of Portland and I suspect they would have to admit the same thing–that telling you about what is going on is something that just has to be done and we’re just going to do it.

Not that my work is as consistent or as high quality as theirs. In fact, it’s simply a product of the time and interest I have to devote to the task–no more, no less.

I try to use a couple of principles to guide me. One is to confirm information. Another is to give others a voice–especially if they disagree. Another is to try to do unto others as you would have them do unto you. It’s a small community. We all make mistakes.

So we do it because we like to inform, because we like to read our own taut script, and because once in a while someone says, “I read that article you wrote and really (liked it) (learned something) (it made me think) (laughed).”

Thank you just for reading.