PISCATWAY, N.J.—The IEEE Broadcast Technology Society has announced that it will host its inaugural “Women in the Industry” breakfast on Oct. 2 during the 2019 IEEE Broadcast Symposium. The event is an opportunity to recognize the accomplishments of women in the broadcast industry and encourage collaboration between them and the BTS.

As part of the event, Jaclyn Pytlarz, senior engineer for Dolby Laboratories, has been tapped to give a keynote presentation. Pytlarz has worked as part of Dolby’s Applied Vision Science group since 2014 and has conducted research on High Dynamic Range and Wide Color Gamut displays. She is currently the lead on the Display Management Core Algorithm, which focuses on developing color mapping and display management algorithms to maintain consistent imagery on a variety of displays. She also is the education director for SMPTE.

The 2019 IEEE Broadcast Symposium will take place from Oct. 1-3 at the Marriott Hartford Downtown in Hartford, Conn.

Visit bts.ieee.org to register for the symposium.

PISCATAWAY, N.J.—The 2018 IEEE Broadcast Symposium is slated to take place Oct. 9-11, but the organization is already accepting submissions for papers to be presented at the event.

The theme of this year’s IEEE Broadcast Symposium is “Media Transmission and Consumption With Emphasis on Disruptive Technologies.” Topics of interest for potential papers can include transmission, IPTV and streaming, OTT, hybrid television and radio, repack issues, ATSC 3.0 and more.

The submission deadline for 200-word abstract proposals is going to be May 1. Extended abstracts of about 1,000 words and the completion of a peer review process will be required for inclusion in the final IEEE Broadcast Symposium conference proceedings. Notification of acceptance will be June 15; submission of camera-ready papers will be Aug. 23.

Accepted papers may be published in the IEEEXplore digital library.

The 2018 IEEE Broadcast Symposium will take place in Arlington, Va., from Oct. 9-11.

In my last column I discussed some of the papers presented at the 2017 IEEE Broadcast Symposium related to the FCC TV spectrum repack. This month I’ll look at presentations that covered broadcast TV antennas.

DESIGNING ANTENNAS

If you ever wondered how antenna patterns are created and why certain patterns seem to show up more often, the presentation “Antenna Design for the FCC Repack and Facility Maximization” by Nick Wymant, chief technology officer at Radio Frequency Systems’ Broadcast Division provided the answers. He also showed techniques for modifying antenna patterns to protect other stations when maximizing a station’s coverage. 

Fig. 1: Typical patterns for slot antenna with 1, 2, 3 or 4 slots around

Wymant started by showing how the numbers of slots around a slot antenna’s pipe affect the azimuth pattern. Fig. 1 shows typical patterns for slot antenna with one, two, three or four slots around. Changing the diameter of the pipe will affect the shape of the pattern. For example, reducing the diameter of the pipe used for the three-slot pattern in Fig. 1 will reduce the depth of the nulls until it becomes a rounded triangle. Additional options for modifying the pattern include changing the amount of power going to the slot elements and adding wings or reflectors to the pipe to shape the pattern. The wide variety of patterns available with slots antennas is one of the reasons they are the most popular antenna type for high-power UHF broadcasting.

It is also possible to create custom patterns using panel antennas, which can be useful if they have to operate on more than one channel and support multiple stations. Panel antennas also offer the option of having different electrical or mechanical beam tilt at different azimuths. Wymant showed how panel antenna array patterns can be modified by changing the relative power and/or phase to each face, changing the array orientation and panel positions, or a combination of these methods.

Finding the right antenna pattern isn’t trivial. If options are limited to standard antenna patterns, a pattern that provides interference protection to a station in one direction will likely lead to reduced coverage in directions that don’t need protection. Wymant’s presentation showed the steps in optimizing antenna patterns to meet FCC replication requirements as well as maximizing coverage while still meeting interference protection requirements. The improved optimization method involves using the replication or interference-limited pattern template as a starting point instead of the end goal, and generating one or more customized patterns using powerful electromagnetic simulation software and evaluating to find the best pattern that meets coverage and FCC interference protection requirements. The paper is available to Symposium attendees and may also be available from RFS.

As a side note, I’ve developed software that uses the output of TVStudy to generate a template based on the minimum power reduction necessary on each radial to comply with FCC interference limits as well as maps showing the location and population of cells with interference. Anyone is free to download and use it. See my columns in IEEE Broadcast Technology (available in print and electronically to IEEE BTS members) or contact me for details if interested. Consulting engineer Merrill Weiss has also developed a program he uses—which was mentioned in Wymant’s presentation—that allows interactive modification of a pattern while viewing the amount of interference. This is useful, especially if the interference is present over a wide area, as it allows trading off more power reduction in one direction for greater power (and more interference) in a more desired direction.

WORLDWIDE EXAMPLES OF ANTENNA DESIGN & INSTALLATION

The presentation, “FCC DTV Repack, ATSC3-SFN Considerations & Worldwide Experiences – SFN” by Mark Fehlig and Ben Crease from Jampro Antennas and Alan Dick Broadcast Ltd. focused on the practical side of antenna selection and outlined some items to consider when designing antenna and transmission systems for ATSC 3.0 and single frequency networks. One of the slides shows DVB-T field strength planning requirements for different types of service. For portable outdoor reception, an outdoor field strength at UHF of 78 dBµV/m at 10 meters drops to only 61 dBµV/m at 1.8 meters. For portable indoor reception, an outdoor field strength of 88 dBµV/m at 10 meters will provide only 63 dBµV/m after reducing height to 1.8 meters and allowing for building penetration loss.

The presentation by Mark Fehlig and Ben Crease from Jampro Antennas and Alan Dick Broadcast Ltd. focused on the practical side of antenna selection.

The rest of the presentation shows some actual antenna installations and performance from around the world using broadband slot and panel antennas. The paper is available to Symposium attendees and should also be available from Jampro at the contacts listed on their web site. 

AMT REPACK STRATEGY

Many TV stations being repacked have their antennas on towers owned by American Tower Corporation. If managing the repack is difficult for one station, imagine what it is like managing the repack of multiple stations on one tower. Jim Stenberg, principal engineer, RF Broadcast at American Tower Corporation (ATC), provided a glimpse of that in his presentation “Adventures in FCC repacking! Broadband Antenna Solutions.” Stenberg’s analysis showed that of the 987 Class A and Full Power licensees moving to new channels, 217 of them are on 133 ATC towers.

Stenberg said the FCC’s timeline faces challenges, notably the impact of weather on scheduling and construction delays by non-repack and FM stations. He also said broadcasters should not undervalue their spectrum, as “cord-cutting” is increasing in almost all markets. He was concerned about broadcasters’ lack of interest in interim alternatives while work is being completed and the minimal value placed on auxiliary facilities that could keep a station on the air. 

The presentation used two ATC towers in Atlanta (Chester Avenue and Briarcliff 2) to illustrate ATC’s approach to the repack using broadband antennas. The goal was to minimize repack disruption by maintaining an optimal coverage contour during repack tower work while future-proofing RF systems to incorporate ATSC 3.0 capability into the design. Some key features include use of broadband antenna systems with dual feed lines and dual combiners capable of operating with different horizontal/vertical elliptical polarization ratios, azimuth patterns designed with low ripple and optimized beam tilt and null fill for the market.

I couldn’t quite follow all the moving pieces in the presentation and I’m sure as maximization applications are granted the pieces will move again. I know ATC is working with broadcasters to develop similar plans for other markets. If you weren’t at the Symposium, contact Jim Stenberg or one of other people in the broadcast division at ATC for a copy.

In my next column, I’ll wrap up my coverage of the IEEE Broadcast Symposium with a review of the papers on antenna pattern measurement with drones. With field measurements of signals a reimburable expense for stations replacing antennas as part of the repack, will stations opt for drone measurements rather than conventional ground measurement of signal strength? What are the tradeoffs? As always, your comments and questions are welcome. Email me at dlung@transmitter.com.

In recent years I’ve noticed the IEEE Broadcast Technology Society has added more presentations on the practical aspects of broadcast engineering to its annual Broadcast Symposium. That was evident this year at the symposium in Alexandria, Va., with several presentations to help broadcast engineers deal with designing, permitting and building the new TV broadcast facilities required as a result of the FCC’s incentive auction and repack.

As usual, the symposium also offered ample opportunity for engineers to share their knowledge and experience in the presentations and during the breaks, reception and meals with few of the other distractions of larger conferences.

This month I’ll focus on some of the spectrum repack presentations at the symposium that took place on Tuesday morning. Look for coverage of other topics, including drone antenna measurements, in future columns.

PRACTICAL REPACK

Matt Sanderford, president of the Dallas-based engineering firm Marsand, presented the most comprehensive, unbiased overview I’ve seen of the practical side of converting a TV transmitter site from one channel to another. Anyone who thought this would be a simple process should take a look at Sanderford’s “Practical Implications of the Repack.”

Matt Sanderford

Sanderford covers the process starting with FCC filings, developing a plan to implement the repack and items to consider when designing the repack facility. Choices for items ranging from transmitters (tube or solid state, liquid or air-cooled) to RF switching (motorized switch or patch bay) and even RF reject loads (oil-filled, liquid-cooled, air-cooled, etc.) are compared.

One point I (and I suspect), many other engineers had not realized is that changing channels requires FAA notification even if the tower height or lighting isn’t being changed! Sanderford reminded us that FAA Form 7460-1, line 21, requires listing frequency and power and that power and frequency changes do not need approval and won’t cause delays, just notification and the amended form.

Regarding the choice of transmitter types, Sanderford noted that high-power liquid-cooled solid-state transmitters have around 40 percent system efficiency, compared with around 34 percent for IOT transmitters. While the tube transmitters may have lower capital cost, they require more maintenance and tube replacement cost is high.

I’ve only touched on a few areas in Sanderford’s paper. The presentation is available to IEEE Broadcast Symposium attendees and may also be available from Marsand. Check Marsand’s website, www.marsand.com for contact information.

INTERFERENCE ISSUE

Merrill Weiss, president of Merrill Weiss Group LLC, discussed “Factors Affecting Mask Filter Selection and Channel 14 Operations in the FCC Spectrum Repack.” Weiss’s paper was not available in the proceedings, but I took notes.

A key point of the presentation was that stations should be using eight-pole mask filters rather than six-pole mask filters in their repack facilities. One reason, as Sanderford mentioned in his presentation, is that an eight-pole filter will allow use of the full OFDM bandwidth available with ATSC 3.0. Weiss focused on interference as the primary reason.

S. Merrill Weiss

TV transmitters, whether using 8VSB or OFDM, will have some energy outside the channel due to intermodulation caused by non-linearity in the transmitter. He pointed out that an eight-pole filter provides a 10 dB reduction in energy into adjacent channels.

When a TV station radiates energy into the adjacent channel, it creates interference on the channel that cannot be eliminated by filtering at the receiver. This will be important after the repack as there will be more stations on adjacent channels.

It will become more important after the transition to ATSC 3.0 for stations that want to use high data rate and higher-order modulation to obtain more bandwidth for additional program streams.

Those signals will require a higher signal-to-noise ratio for reception than today’s ATSC 1.0 signals and on-channel noise from adjacent channel stations without sufficient mask filtering could limit the usefulness of the high data-rate modes available in ATSC 3.0. Be a good neighbor, use an eight-pole mask filter!

Weiss also outlined the issues facing stations moving to Channel 14. Typically a 12-pole mask filter is required on Channel 14. Power has to be down more than 100 dB at the channel edge, as there is no guard band between Channel 14 and land-mobile operations in the 450–470 MHz band. Channel 14 construction permits require notification of potentially affected land-mobile licensees. Documentation must be submitted showing no interference to land-mobile radio services before program test authority can start.

This could be a major problem for Channel 14 stations at sites shared with land-mobile operations. Passive intermodulation (PIM) can cause interference even if the Channel 14 transmitter is perfectly clean. Resolving PIM problems can require cleaning up the entire environment at the site—eliminating rusty bolts, corroded connections and other PIM generating components—as well as installing filters on land-mobile filters and transmitters.

Dennis Wallace, a partner and technical consultant with Meintel, Sgrignoli and Wallace LLC (MSW), described a creative solution to WETA’s Channel 14 assignment in Washington D.C. in his presentation “Creative Solutions to Post-Repack Channel Assignment Problems.” MSW analysis showed there were 5,803 land-mobile facilities within 100 km that would be impacted by WETA on Channel 14. WETA’s original Form 399, available using the Public Search feature in the FCC LMS, shows the station determined the cost of a move to Channel 14 at $48,050,047.50 (total), $40 million of which was for land-mobile remediation.

The MSW solution was to find another channel for WETA, but in a market as congested as the northeast it meant other stations had to change channels and a distributed transmission system (DTS) was required to allow Maryland Public TV stations to use one channel to serve an area previously served by multiple channels. The window for filing for channel changes has ended, but I would not be surprised if some stations assigned to Channel 14 have to consider other channels, potentially requiring cooperation from other stations, before the repack is complete.

Wallace’s presentation is available in the proceedings and may be available from MSW. Also see the MSW website, http://mswdtv.com/dtv-repack, for more information on their repack work.

CHANNEL SHARE

Some stations sold their spectrum in the auction and will share a channel with another station. While I’ve described the basic concept and how bandwidth can be allocated in a previous column, I haven’t focused on PSIP.

Dave Catapano

David Catapano, senior vice president of engineering at Triveni Digital, provided an excellent overview of ATSC 1.0 PSIP for those who may have forgotten how it works. He then looked at some of the complications that arise when two stations with different major channel numbers and different program guides share the same multiplex and RF channel.

One of the benefits of the ATSC A/65 PSIP standard is that key data is duplicated in different tables, making it easier for receivers to find a channel, display the proper video and play the proper audio along with the correct program guide and closed-captioning information. The downside is that if data for a program or PSIP element in one table doesn’t match that in another table, the receivers can do unpredictable things. When adding a second channel, with a new major channel number and new site of guides, stations must keep data consistent across tables and avoid mistakes such as duplicating source IDs in the VCT.

Catapano pointed out that it is important to maintain unique PMTs, PIDs and Program Numbers, and EIT/ETT PID/ID pairs. This can get complicated if output from two PSIP generators is being combined at the multiplexer.

Catapano offered some best practices for shared station PSIP, including using Huffman coding to reduce bandwidth, adjusting EIT/ETT table timing (following A/69), optimizing the number of EITs (they may vary with virtual channel) and limit descriptive info to what’s practical. I’ve only covered a small part of Dave Catapano’s presentation, which can be found in the symposium proceedings and should be available from Triveni Digital’s website, www.trivenidigital.com.

As always, your comments and questions are welcome. Email me at dlung@transmitter.com.

For more information on the repack, visit TV Technology's repack silo.

ARLINGTON, VA.—Broadcast engineers from around the world gathered Oct. 10-12 for the annual IEEE Broadcast Symposium, a forum for exchanging information on the latest developments in the broadcast arena.

Returning to its Washington, D.C. area roots after four years on the road, the conference had plenty of television- and radio-related items on its agenda, with the on-going U.S. TV broadcast spectrum repack and the ATSC 3.0 DTV initiative topping the list. However, the former seemed to draw the most attention.

THE DEVIL IS IN THE (REIMBURSEMENT) DETAILS

Matthew Sanderford

Matthew Sanderford, president of Marsand—a Texas-based broadcast engineering consulting firm—was first in line to describe the repack landscape, noting that nearly 1,000 stations were involved in the operation: 175 sold their licenses, 31 are moving from UHF to VHF channels, 12 are going off the air, and 61 Canadian stations will have to make changes.

“This gives you a picture of the massiveness of what this involves,” said Sanderford, noting that six months into the program’s timeline, government reimbursements for broadcasters have become an issue. “Stations are waiting to start the process of this construction and order equipment, but they can’t do it because they don’t have the funds right now,” said Sanderford. “This is an unanticipated problem; it’s a fear that many had that’s becoming a reality right now.”

He said that one of his clients had recently been informed by the FCC that only 50 percent of the reimbursement amount submitted was currently available, with the commission asking him “what kind of problem is this going to cause for you?” Sanderford said that out of a sense of decorum he would not repeat the answer. “But it was basically ‘we can’t start; just the tower work alone is more than 50 percent of what [was asked for]’.”

He also flagged other issues that could slow the repack, including a lack of RF-experienced personnel. “We have been promoting IT, and the expertise is there in all stations,” said Sanderford, “But RF is not, for the most part. We’re finding out that except for the major markets—and even in many of the major markets—those engineers do not understand RF. They do not even know where the transmitter plant is.”

CHANNEL 14 AND THE REPACK

Dennis Wallace

Another repack issue stems from channel reassignments—in particular, landing on Channel 14—with both Merrill Weiss, president of the Merrill Weiss Group, and Dennis Wallace, a partner in the Meintel, Sgrignoli and Wallace Group, describing what happens when broadcasters are assigned this channel as their new home.

Wallace noted that there was a long-standing history of interference problems involving Channel 14 operators and land mobile radio users, and this will likely be exacerbated by the FCC’s making 33 new assignments on this channel, already home to 15 U.S. broadcasters. “Many of the new Channel 14 assignments are in larger urbanized areas with a large user base of 450 to 470 MHz land mobile operations,” Wallace said.

Weiss described the nature of the problem in detail.

“The baseline Channel 14 is 470-476 MHz,” said Weiss. “And the land mobile service goes from 450-470 MHz, so there is no guard band between a service that can be delivering one megawatt starting at 470.001 MHz and another service that can be looking for a quarter-microvolt signal at 469.9995 MHz, and yet we have to provide protection, so this gets a wee bit crazy.”

Weiss also flagged an additional issue with the potential to slow down the repack, stemming from significant changes in the FCC edict requiring Channel 14 operators to protect land mobile services. “[The mandate has] always been there,” said Weiss. “But it’s never been worded the way it is on repack Channel 14 construction permits.” He then read the updated FCC requirement:

Merill Weiss

“During equipment tests, permittee shall take measures to identify and eliminate objectional interference which may be caused in the 460-470 MHz band. Documentation that interference will not be caused shall be submitted. Program tests shall not be commenced, and may only be started after specific authority is granted by the Commission.”

“So, unlike in the past where program test authority was automatic when the facility was built, we [now] have an obligation to go out and prove and document that no interference will be caused,” said Weiss.

In describing the impact that a Channel 14 reassignment can have, Wallace used Washington, D.C.’s WETA-TV as an example. The station now operates on Channel 27, but was told it has to move to Channel 14. “Our firm did an analysis of the situation and found 2,136 land mobile licensees were within a 100-km distance [of the WETA-TV transmitter], and an interference study revealed about 1,200 licenses would be impacted from WETA-TV Ch. 14 operations,” said Wallace.

He observed that it would be impossible to resolve such a large number of potential interference cases in a timely manner. The only solution appears to be a different channel assignment. However, such a move has been made very difficult due to other station reassignments and short-spacing issues. Wallace said that a number of scenarios were developed, but only one seemed workable: relocate WETA-TV to Channel 31. However, this move would require six other stations to either change channels, make power adjustments, or install a new mask filter.

NO ROOM IN THE SCHEDULE FOR CONTINGENCES

Joe Seccia, manager of TV transmission market and product development strategy at GatesAir, flagged other potential transition issues.

Joe Seccia

“In phase one, there are 94 stations that have to be repacked by Nov. 30 next year. That’s one station every three days, starting right now. As we slide down toward November, maybe the last 60 or 30 days of phase one, we’re going to go from one station every three days to three stations a day that need to move. That doesn’t bring into account the 114 stations in phase two that are also having to do simultaneous work. That’s a lot.

“There’s no slack; there’s no float in the schedule, but those are the rules of the auction. There’s a lot to do and seemingly not enough people to do it,” Seccia added, remarking that the recent deaths of tower workers in a Florida accident was a wakeup call about what can happen to plans and schedules.

“We’re just getting started and boom—very sobering.”

Next year’s IEEE Broadcast Symposium will take place in Arlington, Va., Oct. 9-11.

For more information on the repack, visit TV Technology's repack silo.

Robert Weller

ARLINGTON, VA.—The 2017 IEEE Broadcast Symposium returned to its Washington, D.C. area “roots” today after four years on the road. The technical conference, which has been an annual industry event since the early 1950s, kicked off with opening remarks from Society president William Hayes, who then introduced Symposium co-chair, Robert Weller.

“Welcome to the 67th IEEE annual broadcast symposium,” said Weller. “We have over 170 people registered this year, which testifies to the importance that working engineers and consultants place on this event,” noting that sessions would feature a number of industry leaders and cover a variety of technologies, including the U.S. TV broadcast spectrum repack, hybrid radio and more.

Before beginning the scheduled presentations, Weller shifted to a somber note, asking conference attendees to observe a minute of silence in memory of the three TV tower workers–Brachton Barber, Marcus Goffena and Benito Rodriguez–who lost their lives in the recent Miami job site accident.

Symposium attendees pack the presentation room at the Key Bridge Marriott hotel in Arlington, Va., the venue for this year’s event.

More than 30 broadcast-related papers are scheduled for delivery during the Oct. 10-12 conference, with topics ranging from cybersecurity to the development of cameras for 8K UHD operation, and presenters traveling from as far away as Japan and Korea. In addition to conference track presentations, the Symposium will also feature luncheon keynote addresses with speakers from the Department of Defense, the Library of Congress and the Drone Girl organization.

PISCATAWAY, N.J.—Details for the 2017 IEEE Broadcast Symposium have been announced, with the annual conference scheduled from Oct. 10-12 at the Key Bridge Marriott in Arlington, Va.

The Broadcast Symposium is designed as a meeting of broadcast industry experts from around the world and offers a three-day program of tutorials and technical sessions, as well as the new addition of a poster sessions and exhibits.

For more information on this year’s IEEE Broadcast Symposium, visit bts.ieee.org/broadcastsymposium.

MELVILLE, N.Y.—People are now able to register online for the 2016 IEEE Broadcast Symposium, which is scheduled to take place from Oct. 12-14 in Hartford, Conn. The three day conference will feature tutorials, technical sessions and networking.

In addition, IEEE Broadcast Technology Society is seeking sponsors for the Symposium. Sponsors will have their logos displayed on the event’s website, in the conference program, in email and print promotions, at their own sponsored session, and at general sessions.

IEEE is offering a discount registration fee for past attendees, as well as for anyone who registers before June. For more information on the 2016 IEEE Broadcast Symposium, click here.

MELVILLE, N.Y.—Following the 2015 IEEE Broadcast Symposium that took place in Orlando, Fla. in October, IEEE BTS has announced the date and time for the 2016 edition. The 2016 IEEE Broadcast Symposium will take place Oct. 12-14 in Hartford, Conn. The Hartford Marriott will host broadcast engineers from around the world for a program of technical sessions and networking.

IEEE BTS will open the call for papers and sponsors in the coming weeks. For additional information, visit bts.ieee.org.