Category Archives: 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.

 

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.

FCC Issues Forfeiture Order to San Diego 96.9 Pirate

The FCC issued a Forfeiture Order in the case of the Free Radio San Diego FM pirate on 96.9 MHz from the South Park area of San Diego east of Balboa Park. Donald Payne, registered as the owner of the property at 1937 33rd Street near Grape Street, was ordered to pay the FCC $750. His fine was reduced from $10,000 after he filed income documents that demonstrated to the Bureau that he couldn’t afford the higher fine. The latest document indicate that FCC inspectors had been monitoring the illegal station from April to December of 2006. Payne was issued a Notice of Apparent Liability in late December of 2006. He told the FCC that he did not operate the station but the FCC holds him responsible as the property owner.

We interviewed the pirate broadcaster known as “Bob Ugly” two years ago. Free Radio San Diegoclaims they are currently off-the-air, webcasting only.

A Better TV Reception Predictor

Antennaweb.com revolutionized the concept of predicting TV reception for a new generation of enthusiasts installing over-the-air antennas. It graded reception by color and gave recommendations, if flawed, about what kind of antenna to put up. When they went conservative with the results, those who had put real work into their systems found the predictions only listed a fraction of the stations they could get.

For those who want a little more science, there’s a new kid in town. Try out TVFool.com and for the address you enter, you will get a chart of precisely calculated reception parameters. I especially like the listing of antenna heights needed for line-of-sight (LOS) and -100 dBm thresholds. You also get a marker for all those nasty co-channel allocations we have in SoCal now.

It turns out that for my home just east of La Jolla, predictions come pretty close, though I’m guessing that some transmission antennas outperform predicted levels because of what I see on my flat response receive antenna. For example, I consistently receive KCBS-DT (real channel 60) better than some locals and better than even consistent KTLA-DT 31 on my recently rebuilt Create log-periodic. In reality, there are numerous factors that I haven’t bothered to measure scientifically, but the empirical results match closely enough those of TVFool.

Making Waves: RIP Gateway Electronics

Those of us who love to homebrew and tinker have lost a friend when Gateway Electronics in San Diego closed their doors in late April. The store sold a couple of years ago, but Manny and Fong couldn’t keep the cash flow positive, and a new lessee was to take over.

Here’s why I think Gateway closed:

  • People don’t have the time to tinker;
  • The integration of electronics has become so cheap and large-scale that small-scale projects don’t have much value;
  • Specialized small electronics items can now be found online;
  • The internet has made it possible to repurpose surplus gear through auction and direct sale sites without using retail outlets; and
  • Because of all of the above, retailers additional cash streams through either technical services, web sales, or local sales of higher traffic computer gear.

My favorite Gateway find was when, while looking at their selection of LEDs at the front glass counter shelves I saw in my peripheral vision a small container of tiny mechanical clocks. These are the kind of sealed, elapsed time counters they put on very expensive equipment that allowed you to log and time maintenance. This was in the mid-1990s when KFMB-TV had in service four Philips LDK-6 Plumbicon studio cameras that made great pictures. But their camera head timers had a habit of making a terrible noise when they presumably wore out their internal gears or just lost their lubrication. Philips charged $400 each for the neat-looking devices the size of your thumb. As far as I know, the LDK-6 may have been the only product they made that used this special 400Hz clock, and they had to manage their inventory and pay tax, year after year. Having worked in manufacturing, I understand parts costs. But here they were at Gateway, small, matte black, 400Hz, 100,000 hour elapsed time counters, $5 each. I bought four and we installed at least two of them over time.

I also liked their supplies of cheap LEDs, connectors, stainless hardware, and a great line of prototype circuit boards. They also stocked all kinds of transformers, switches, basic kits, and computer cables. Some items, like used switches and some really old test gear, you might not want to take home for fear of creating more of an expediture of time and energy than a savings that good engineering practices would dictate.

Gateway wasn’t the only surplus electronics supply store in the region, but they were the only one in Kearny Mesa within a short drive from most broadcast outlets. Industrial Liquidators doesn’t really count–they’re useful for some tools and pneumatic supplies, but have very little electronics stock. Murphy’s and California Surplus continue to operate from the same neighborhood of Johnson Avenue in El Cajon, and I’ll be the first to say that they do a good job of keeping their shelves tidy enough to make hardware relatively easy to find. If you ever have to replace or install a new one of those mil-spec MS “Amphenol” connectors, Cal. Surplus has a huge barrel of them that has saved me from the misery of waiting 8-10 weeks for a new one. Willy’s Electronics in National City still stocks some hobbyist electronics supplies, but its all new stuff and you pay full retail price. There’s the monthly Santee Swap Meet, but with the internet and declining electronics hobby, it’s become more of a big garage sale. I visit once a year for a load of tools, hi-fi cables, and fresh avocados.

The king, the acme, nay, the apex of surplus electronics is Apex Electronics in Sun Valley in the heart of the San Fernando Valley in Los Angeles. I happened by there once when, during a visit to my mother-in-law’s, I took a side trip. With an acre or so of indoor shelves that must be 20 feet high and an outdoor lot of surely another couple of acres, this place is big. Good luck in an earthquake, pal. Take the virtual tour on their website. Microwave gear for pennies on the dollar, though that was before the price of copper went through the roof. If they don’t have what you want, then you should reconsider your design.

Epilogue

When Manny and Fong closed the Gateway doors, they handed out little pieces of paper with contact information and a promise of opening a new store. I tried to call and write to ask a few questions, but have yet to receive a reply.

What are your experiences with surplus buying? Are there other Southern California stores you know about? Tell us about it.