WASHINGTON—The Federal Communications Commission’s Office of Engineering and Technology and Media Bureau have released updated TVStudy software (v2.3.1).

TVStudy is open-source software developed by the agency to analyze the coverage area, population served, and potential signal interference when evaluating channel changes and station repacking for full-service digital and Class A television stations.

The TVStudy v2.3.1 software installation package, the TVStudy 2.3.1 Installation and Upgrade Guide, and the post-auction template XML file are all available on the TVStudy website.

As with prior updates, a full list of changes from TVStudy v2.3 is included in the “Differences Between 2.3.1 and 2.3.0” section of the change log in the TVStudy 2.3.1 Installation and Upgrade Guide.

The FCC reported that TVStudy 2.3.1 corrects an issue that caused applications for new low-power television stations to be considered incorrectly in TV Interference Check studies. TVStudy 2.3.1 also corrects several minor issues throughout the software and adds a handful of minor features.

For further information on the TVStudy software and to submit bug reports, contact Mark Colombo at 202-418-7611 or Mark.Colombo@fcc.gov.

ALLENTOWN, Pa.—WFMZ-TV 69 is an independent VHF station serving the Lehigh Valley and Berks County of eastern Pennsylvania. At 80.6kW ERP, WFMZ’s over-the-air signal penetrates the Philadelphia market to the south, east into New Jersey, and several counties north and west.

After the repack ended in 2020, WFMZ moved from its 800kW UHF Channel 46 to WBPH Bethlehem’s 80 kW Channel 9, also shared by WLVT Bethlehem, which also broadcasts WPPT Philadelphia in SD on its shared space.

Post-Repack Challenge
Post-repack, various technical challenges reduced our signal penetration. The original Channel 9 antenna was a Horizontal polarized six-bay directional antenna with a transmitter TPO of 10kW. The sharing partners agreed to solve the lost signal problem by moving to an omnidirectional, four-bay antenna system with 50% horizontal and 50% vertical polarization and doubling the power of our existing GatesAir 20kW Maxiva VAXTE VHF transmitter to 40kW TPO. 

To my understanding, this is the highest power air-cooled VAXTE transmitter GatesAir has produced, and it has once again powered our signals into the neighborhoods we lost post-repack. 

We had the choice of increasing our transmitter size or starting over with liquid-cooled. We chose the former, and our refurbished Maxiva VAXTE went live in January 2023.  Along with price point and confidence in their longevity and technical support, we stayed with GatesAir because they were a common denominator for all three broadcasters in the channel-sharing agreement.

That importance is amplified by the fact that the transmission systems are on the WFMZ property. WFMZ’s studios and tower are colocated on South Mountain in Allentown, and we have long hosted the other two stations’ transmission systems.

GatesAir and their installation partner managed the original installation and upgrade. We updated the coaxial and electrical infrastructure inside our transmitter building in 2018, and installed a constant impedance filter (CIF) to take the VAXTE signal to the antenna. Rather than replace it in the upgrade, 

GatesAir suggested we add a second CIF to the “new half” of the transmitter and combine the two signals at the output. With 48 power amplifiers in the VAXTE, managing the timing, combining and line lengths for the RF signal, sampling, measuring, and correction is a weighty challenge. Their service team worked through those challenges, and the result has been impressive.

The New Footprint
Our new transmitter footprint spans six cabinets, with eight amplifier modules per cabinet. While that seems big, it is expected for an air-cooled transmitter at this TPO. Full-sized doors on the rear of each cabinet provide access for maintenance. Replacing an amplifier module is simple, with only some quick disconnects required while the transmitter remains on the air.

We use redundant Maxiva XTE exciters in the transmitter. These are ATSC 3.0-upgradeable units that provide stable power and meet all performance specifications for the signal. The VAXTE’s web GUI allows us to monitor exciter performance and drill down to see the voltages, currents and temperatures for each PA module, as well as reflected power and general power output from the transmitter. Connectivity to a remote-control system provides alarming if any power thresholds are crossed.

Viewer response to the increase has been positive. A contributor to an online local broadcasting forum recently commented that WFMZ’s signal once again reaches into his neighborhood on the market’s outer edges, and a family member of our staff reports she can now receive the station at her home northwest of Philadelphia. That tells me that the transmitter and antenna system upgrade have fulfilled the purpose of improving our coverage.  

More information is available at www.gatesair.com.

The deadline for Phase 4 of channel repacking in the FCC’s incentive auction has passed and it appears to have been the most challenging one to date. This month I’ll outline some of the Phase 4 experiences and lessons for future transitions, and provide some tips on helping viewers with rescan and reception issues.

I was on the 90th floor of One World Trade Center in New York with the transmitters on Aug. 1 when many stations in Hartford, Conn., New York, Philadelphia and Washington D.C. transitioned to their new channels. The switch took place at 1 p.m., in the middle of the day and not at the 11:59 p.m. Aug. 2 deadline. Boston changed channels at 1:05 p.m. the next day.

Switching channels in the middle of the day has several advantages, the main one being more staff available to help resolve problems or answer viewers’ calls. While the FCC set the phase deadlines on Friday just before midnight, stations can transition anytime during the FCC test period before the deadline on the condition they provide proper public notice and coordinate with other stations.

The Phase 4 deadline was not the trainwreck many feared, but not all stations were able to operate with their final facilities. In at least two markets, New York and Boston, many stations were not able to transition to their final antenna or power because work could not start on the final facilities until the old channels were shutdown. In both cases, however, this had little impact on coverage.

ONE WORLD TRADE CENTER

UHF stations at One World Trade Center were all operating on the upper antenna (RFS PEP40 panel array) on their old channels at reduced power while the RFS combiners (two are necessary to achieve variable polarization) associated with the lower antenna (RFS PEP96L) were tuned to the new channels. You can see a snapshot of the job configuring and tuning the One World Trade Center combiners for the new channels in Fig. 1.

On Aug. 1, One World Trade Center UHF stations switched to the lower antenna and combiner system. For some stations, this was the antenna authorized in their construction permit, but even though they were able to test individually at full power they had to reduce power before all the UHF stations (WCBS-TV, WLIW, WNBC/WNJU, WNYW, WWOR-TV, WPXNTV) could operate on the antenna with a good safety margin. The impact on coverage from use of the One World Trade Center lower antenna and power reduction is minimal, thanks to the overall height of the antenna.

The channel changes occurred on time without incident thanks to the cooperation between all stations involved, including those out-of-market stations receiving interference during testing. Kudos to the tireless work by Joe Giardina and his team at DSI, along with the engineers from RFS, configuring the combiners and Durst Broadcasting’s John Lyons management of the project with what seemed like 24/7 availability.

In Boston, UHF stations on a tower owned by American Tower switched to a shared auxiliary antenna system, which closely matched predicted coverage from the main antenna system now under construction.

An easy way to check whether a station is operating at its final power level on its licensed facilities is to use the LMS search feature under “Technical Data” for the station (https://enterpriseefiling.fcc.gov/dataentry/public/tv/publicSearchLanding.htmlorwww.rabbitears.info).

On www.rabbitears.info, a nonprofit website that tracks broadcast RF developments, “DTV-STA” indicates the station is operating under FCC special temporary authority, usually at reduced power or height. “DTV-LIC” indicates the station is licensed while “DTV-PL” indicates the license is pending. “DTV-CP” indicates the station still has a construction permit for the final facility. For Phase 4 stations, the CP expiration date was Aug. 2, 2019. Stations that were unable to complete construction of their final facilities were allowed a six-month extension of the construction permit to Jan. 29, 2020.

In my last column I described the importance of testing facilities before transitioning. At some of the stations I was working at, this turned out to be a valuable step as problems were discovered (and fixed) prior to the transition that would have caused major problems if they occurred after the switch to the new channels.

In situations where the channel was already in use in the market, the only way extended testing was possible was for the testing station to carry the ASI stream from the current channel occupant during the testing, avoiding any impact to that station’s viewers. Unfortunately, post-transition I saw some problems arise that were not caught during testing. Fortunately, the ones I’m aware of did not take the stations off the air for extended periods of time, but did result in some power reductions and temporary loss of coverage. Extended testing, for as much time as possible, prior to the transition date, should be a priority.

RESCAN REMEDIES

With channel changes comes the need to rescan. What happens, however, if during the first rescan the viewer is unable to receive the channel, perhaps due to the new channel operating at reduced power or height? Here are some tips that may help these viewers.

For technically savvy viewers, some TV sets have a signal quality indicator. If other stations are transmitting from the problem station’s location, optimizing the antenna using this signal meter may allow a rescan to pick up weaker stations. Viewers that are less technically savvy are likely to be confused by this solution.

A simpler option, which can avoid the need for a complete rescan, is to tune the TV set to the RF channel and program number (“Physical Channel” in the Rabbitears listing) of the station. For example, in the case of WRC-TV in Washington, D.C., the RF channel is 34 and the program number for NBC is 3. Punching in 34.3 on a TV set’s remote should take the TV direct to NBC, and, once locked, the displayed channel will change to 4.1.

Channel up to see the other subchannels. If there is no reception, the TV set should stay on 34.3, and the viewer can move the antenna to try to find a location or orientation where the signal can be received. Note this only works in markets where the RF channel and program number combination are not in use as a virtual channel by another station that’s been previously scanned. This should work on most TV sets, but I’d appreciate hearing from readers on the results of using this direct tuning method, noting the make and model of TV if possible.

For many broadcast engineers, www.rabbitears.info is the first stop for information on TV stations. The site provides excellent coverage maps showing contours and field strength as predicted using the Longley- Rice terrain sensitive model. The site has a new feature in beta—the Rabbitears Search Map—available at www.rabbitears.info/searchmap.php. You can enter an address in the box on the lower left of the map, then use the “Move Pushpin to Center of Map View” to put a marker on the exact location, as shown in Fig. 2. An example of the output is shown in Fig. 3.

In markets with stations using mechanical beam tilt on antennas on high mountains, such as Los Angeles, the results from the Rabbitears Search Map will be much more accurate than those from other coverage prediction sites like www.tvfool.com and even the FCC’s www.fcc.gov/media/engineering/dtvmaps. The reason is that many of the antenna patterns stored in the FCC’s database for antennas with mechanical beam tilt are based on the horizontal plane radiation pattern—the power going straight out from the antenna and never hitting the ground. This is why the antenna patterns for Mt. Wilson stations appear to be aimed at Lancaster rather than Los Angeles. Where actual un-tilted antenna pattern is available, Rabbitears uses that pattern rather than the highly distorted horizontal plane antenna pattern, resulting in a much more accurate representation of signal on the ground.

The Rabbitears Search Map should be handy for engineers taking calls from viewers with reception problems as they can enter the address into the map and see what stations the viewer should be able to receive and at what signal strength.

ODDS AND ENDS

Finally this month, I have heard from some sources that Winegard has discontinued or will be discontinuing my favorite indoor/outdoor antenna, the Winegard Freevision FV-30BB. I hope that is not true. The antenna still shows up on Winegard’s website for $39.99 and remains available at some Home Depot stores.

This is the antenna I’ve been using for field strength measurements as it is small, works well on high-VHF, and even does a passable job on low VHF. I was surprised how well it worked picking up WPVI’s Channel 6 signal in Philadelphia during testing there. There are other antennas that have more gain and will do a better job at UHF and VHF, but none I’ve found that are as small as this one—easy to hang on a wall; easy to throw in a car trunk with the mast connected; easy to support on an extendable pole.

One thing I’ve noticed, as have some on www.avsforum.com/forum/25-hdtvtechnical, is that the antenna performs much better than the specifications and patterns from Winegard would indicate. I hope Winegard continues to manufacture it.

As always, I welcome your comments and questions atdlung@transmitter.com. Responses may be delayed if I’m busy, bug me again if you don’t get an answer in a week or two.

For more news and insight on the repack, visit TV Technology'srepack silo.

WASHINGTON—As the federal government shutdown enters its third week, the FCC announced on Thursday that it was suspending most of its operations until the government re-opens.

As it warned earlier this week, the following FCC functions will be available during the lapse in operations:

• Network Outage Reporting System (NORS)

• Disaster Information Reporting System (DIRS)

• Public Safety Support Center (PSSC)

• Licensing Management System (LMS)

• Consolidated Database System (CDBS)

• Electronic Comment Filing System (ECFS)

• Universal Licensing System (ULS)

• Electronic Document Management System (EDOCS)

• Auctions Public Reporting System (PRS)

• Auction Application System

• Auction Bidding System

• Daily Digest, and

• Commission Online Registration System (CORES).

All other commission electronic filing and database systems will be unavailable to the public until normal agency operations resume, the FCC said. The Consumer Complaint Center (including the main FCC Call Center) will not be operating.

Activities related to the broadcast channel repack and the 28 GHz spectrum auctions will continue and content on the agency’s website will still be accessible to the public but will not be updated except news related to the auctions and—as always—“matters necessary for the protection of life and property.”

Any STAs expiring during the suspension are extended to the day after regular commission operations resume except those STAs related to the repack. Emergency STA requests involving potential risks to life or property will be processed through the FCC Operations Center (202-418-1122) while the commission’s electronic dockets and other online resources are unavailable.

The FCC’s Fee Filer System will not be available while operations are suspended, and therefore no regulatory fee or application fee payments can be made through Fee Filer during the shutdown. Deadlines for payments are not being extended; however since the Fee Filer system will not be available, only payments made to US Bank will be processed.

The Commission’s informal 180-day time clock for review of transactions is also suspended. 

For more information, read the FCC's notice. 

RAYMOND, MAINE–DTVPros and GTI America recently partnered to relocate a Tulsa, Ok.-based TV station’s transmission facilities to comply with the current spectrum repack.

KWHB, a Family Broadcasting Corporation station serving Tulsa and Northeast Oklahoma, relocated to the tallest building in the CityPlex Towers office complex upon being repacked from UHF Channel 47 to Channel 16. This 60-foot skyscraper is also the longtime home of Oral Roberts University-owned KGEB-DT, an independent broadcaster repacked from UHF Channel 49 to VHF Channel 12.

Both stations hired DTVPros, a full-service buyer’s agent that specializes in RF system planning and selection processes for local TV stations, to manage the unique relocation project. The complex project required helicopter lifts to remove existing KGEB antennas, and install new Dielectric repack antennas for each broadcaster’s new channel assignment. New antenna mounts were also required to comply with modern building codes.

Working closely with GTI America, the broadcast services company in charge of installation, DTVPros coordinated services and equipment to meet each station’s repack deadline. KGEB, a Phase 0 repack station, cut over to its new VHF Channel 12 assignment on Sept. 4 while KWHB, a Phase 2 repack station, will begin broadcasting on UHF Channel 16 in April 2019. DTVPros also worked closely with Hodge Structural Engineers of Evansville, Indiana, to produce the new specially designed mounts.

“This was a very unusual project as the installation was to take place on a building in a congested metropolitan area as opposed to a remote broadcast tower,” said Jim Heard, owner of DTVPros. “Additionally, the existing mounts were no longer in code, and we were under a tight timeline to find a helicopter service for antenna removal and installation. These were all obstacles that made overall program management among the most challenging of my career, but the professionalism of my partners shined through.”

Dielectric supplied elliptically designed antennas for both stations for enhanced coverage and performance in ATSC 1.0, and in preparation for ATSC 3.0. Once live on Channel 16, KWHB will use a TFU GTH Series UHF broadband slot antenna, which offers an electrically center-fed design for superior frequency response across one or more channels. KGEB is broadcasting from its new VHF assignment with a THV Series high-band directional antenna. The complete systems for each station also included Dielectric tunable waveguide filters and HELIAX flexible transmission line from CommScope.

For all the latest news and insight on the repack, visit our repack silo.

SALT LAKE CITY— In March 2017, DTV Utah began plans on repacking six of its eight DTV Utah Stations that were required to change frequencies as a result of the spectrum auction. DTV Utah, LLC is a television transmitter site located in the Oquirrh Mountains above Salt Lake City, Utah, and was the location of a complex, channel repack project involving nine UHF television stations, with eight of the transmitters combined into a community antenna.

DTV Utah, LLC was formed in 1998 as a nonprofit corporation that owns and operates the community television facility. Greg James of Bonneville International originated the concept of a community site for the new digital service.

“The discussion revolved around the problem created for viewers, if stations were dispersed over a wide geographic area,” James said. “As I thought about multipath in the mountainous area we live in, it made a lot of sense to broadcast from a single location.”

[Read: Eight TV Stations On One Stick Ponder Repack]

Other benefits of co-locating the markets transmitters include economies of scale and reduction of intermodulation interference.

The television stations currently in the DTV Utah group include:

• KSL (Bonneville International)
• KUTV and KJZZ (Sinclair Broadcasting)
• KTVX and KUCW (Nexstar)
• KUED and KUEN (University of Utah)
• KBYU (Brigham Young University)

The DTV Utah site is located 9,000 feet above sea level, with limited access via a 10-mile single-lane dirt road, limited space for construction and a limited seasonal construction window of four months due to weather conditions and road access.

The original DTV Utah site consisted of two four-channel Dielectric combiners, connected to either the main Kathrein antenna, or to an auxiliary antenna through a complex waveguide switching network with five modes of operation. In addition, all eight stations could be combined together and routed to any of the three antennas.

COMPLICATIONS ARISE

It was soon discovered that the original WR 1500 waveguide was not going to pass the new frequencies. The existing Kathrein community antenna also required evaluation to determine if it would perform under the new parameters. The repack design was also complicated by the frequencies that were assigned. Channel 34 (KUTV) and Channel 36 (KUEN) did not require change, but as fate would have it, Channel 35 was assigned to KUCW, creating three adjacent channels and potential intermodulation issues.

Other challenges included transmitter cooling at the thin air of 9,000 feet, transmission line performance, and the requirement to stay on the air while creating a seamless transition to the new channels.

The repack design included a patch panel that provided a path for the N+1 transmitter to replace any of the eight transmitters at the input of the combiner.

Marsand Inc.'s Matthew A. Sanderford, Jr. PE and David Sanderford installed the transmitters while Legacy Electric of Salt Lake City did the electrical work. Tower and antenna work was performed by GTI, America and Burk Technology designed the control system. Climate Control (CCI) handled HVAC.

TRANSMITTERS AND COMBINER

Each station decided on the make and model of the eight new transmitters; Five Rohde and Schwarz THU9evo transmitters and three Gates Air Maxiva UXLT transmitters, including the N+1 transmitter were installed along with one Dielectric combiner and six Dielectric WR1800 waveguide switches for nine different combiner/antenna/test load modes.

Each station purchased their own transmitters based on their own evaluations. “Given the complexity of the project, I suggested one installer for all of the transmitters,” James said. “It would have been a nightmare to schedule different crews on each transmitter. The same was true for electrical, HVAC, and so on.”

The new Dielectric, dual four-port combiner was installed in a very tight 20 x 17 x 9-foot space.

How do you keep your station on the air, while removing your old transmitter and installing the new one? All eight stations were operated at lower power into the auxiliary community antenna through the period of construction and transition. The GatesAir N+1 transmitter was delivered with broadband power amplifiers. As the N+1 was placed on the air, the old transmitter was decommissioned and the new transmitter installed, tuned to the original frequency and tested through the combiner/mask filter to a load.

SEVEN-DAY PROCESS

Each transmitter switch-out took about seven days and the process of bringing each transmitter on line was complex. First, engineers had to run transmitter power at the level that delivered the power calculated to meet ERP requirements of the station, when measured at the dummy load at the output of the combiner. They then had to measure the input power to the combiner hybrid; measure transmitter power out, and calibrate that as 100 percent power. This had to be repeated for each of the four profiles in each transmitter.

A spectrum analyzer was used to perform a power-band measurement on the four combined channels to verify spectrum compliance. As a final step, each station’s reflected power spectrum was recorded to determine a baseline for monthly performance tests.

COMMUNITY ANTENNA REBUILD

The original Kathrein antenna (two Kathrein eight tier by three bay antenna systems—48 panels total), was selected because of the extensive use of the antenna in the Swiss Alps. The temperature extremes at the DTV Utah site are very similar to the Alps, with a thermal swing of over 100 degrees winter to summer (-18F to +85F) Grundy Telecommunications Inc., America, was asked to review the existing Kathrein community antenna system and Kathrein Antenna Works sent an engineer who helped in the evaluation. After band sweeping and physical inspection, engineers determined that the existing antenna system would not perform well for the repack system.

The original tower was custom-built to support the Kathrein 70 x 6-foot radome cylinder. DTV Utah considered replacing the antenna with a different make and model, but structural modifications to the tower would have made replacement cost prohibitive. Kathrein was asked to develop a replacement antenna system … since the radome cylinder supported the antenna, it seemed possible to remove the old antenna system and replace it with a new one.

The next step was demolition and rebuild of the antenna system. Grundy removed main power dividers, cabling harnesses, tier power dividers and panel mounts—some three tons of it—in less than a week. The crew then began installing the new antenna, and six weeks later the rebuilt antenna system was ready for testing.

Katherine field engineers did a proof-of-performance; results were good with the lower antenna showing 28 dB return loss on the lower antenna and 30 dB return loss on the upper; this equates to a VSWR on the upper in the 1.08:1 and the lower antenna at 1.1:1.

OTHER SYSTEMS

For the Burk remote control system, equipment was specified and truth tables developed for interlocking. In some of the modes, reduced power is required. The Burk unit can talk to the transmitters based on the selected mode and ensure that their power levels are correct. If not, the it will shut the offending transmitter down and alert the operator.

Transmission line arc protection was provided by South-Tek Systems, N2-GEN, nitrogen generators.

RESULTS

After a month and a half of construction, all transmitters were installed and operating on the old frequencies. Once all transmitters were installed, commissioned and tested, the new transmitters were retuned to the new frequencies and switched into the refurbished community antenna.

Mario Hieb is a professional broadcast engineer based in the Salt Lake City area.

For all the latest news and insight on the repack, visit our repack silo.

ALEXANDRIA, VA.—The Great TV Channel Auction and Repack is now underway, with television and FM radio broadcasters doing the necessary work to change frequency assignments and install new equipment. It is a lot of work, but progress is being made daily.

In addition to the repack project work now underway, the FCC is currently asking for comments about the repack process and reimbursement for affected Class A stations, low-power TV stations, translators and FM broadcasters; deadline is Oct. 26. In addition to the full-power repack, as many as 1,000 smaller stations are being moved in 10 phases, which will cause dislocation and incur some expenses for LPTVs and translators that were not protected in the repack. This also affects some FM stations colocated on TV towers.

In the event you’ve been lost in space for the past two years, the Channel Auction and Repack exists to shift TV broadcasters to VHF and lower-UHF channels, with the goal of freeing up spectrum for wireless services for mobile devices. A distant model was the BAS Relocation program from 2005 to 2010, which also had broadcasters giving up a slice of spectrum for the benefit of a cellphone company.

Since the process began in the spring of 2017 after a spectrum auction that yielded approximately $20 billion to the federal government, more than 120 full power and Class A television stations have moved off their pre-auction channels, according to Jean Kiddoo, chair of the FCC’s Incentive Auction Task Force.

“Approximately half of those stations chose to move before the first formal transition deadline,” she said. “The other half consists of stations that won incentive payments during the auction but elected to continue broadcasting by sharing a channel with another station, and have now implemented those channel-sharing agreements.”

NOW UNDERWAY

By the time you read this article, the first formal phase of the Channel Auction and Repack is now underway. Kiddoo said that the testing period for Phase 1 of the repack began Sept. 14 and ends Nov. 30. There are 82 full-power and Class A television stations scheduled to transition during Phase 1.

[Read: Transitioning To New Channels—Phase 1 Deadline Looms]

Obviously, re-assigning channels of TV broadcasters and radio stations is an expensive proposition, fraught with complex engineering challenges as well as concern about changes in propagation and coverage. Congress appropriated funds to pay for this work, and broadcasters have been receiving reimbursement.

“The initial reimbursement fund totaled $1.75 billion, and as of April 16, 2018, virtually all of that [$1.742 billion] has been allocated by the FCC,” Kiddoo said. “That represents 92.5-percent of total estimates for each station. “Stations have been able to draw down against their allocation by submitting invoices for eligible costs incurred since October 6, 2017.”

As for the remaining 7.5-percent of the projected costs and additional expenses, it appears to be on the way.

“Congress provided additional funding in the 2018 Omnibus Appropriations Act to reimburse reasonable costs incurred by full power and Class A broadcasters as well as previously-ineligible LPTV/TV translator and FM stations,” Kiddoo said. “The rulemaking to adopt rules and procedures to reimburse the latter is anticipated to be completed in the first quarter of 2019.”

How does this translate to the real world of actual broadcasters going through the repack work? Dale Scherbring, a regional director of engineering for Sinclair Broadcast Group and the company’s repack manager, said the project is keeping him busy.

“The Sinclair Broadcast Group’s engineering team has been working on 100 repacks for the company-owned stations and fulfilling contracts with our partner stations,” Scherbring said. “Phase 0 stations and one Phase 1 station have made the transition and are on the air.”

Phase 0 stations on the air include:

• WCHS (Charleston, W.Va.)
• WDSI (Chattanooga, Tenn.)
• WICD (Champaign, Ill.)
• WNUV (Baltimore, Md.)

The only Phase 1 station moved so far is KJZZ (Salt Lake City).

Scherbring said that the company’s Phase 1 stations currently in progress for repack work are:

• KBTV (Beaumont, Texas)
• KFDM (Beaumont, Texas)
• KMEG (Sioux City, Iowa)
• KPTH (Sioux City, Iowa)
• KMPH-CD (Fresno Calif.)
• KRXI (Reno, Nev.)
• WNWO (Toledo, Ohio)

“The remaining 88 stations are in various stages of equipment order, tower studies and overall planning,” he said.

MASSIVE SCOPE

There has been a lot of discussion about the massive scope of this project versus the relatively small size of the broadcast equipment manufacturing industry. In other words, would the manufacturers of transmitters, antennas and ancillary components be able to build high-quality and reliable equipment for the repack in the relatively short time frame for which the project is scheduled? Then, will there be sufficient crews to properly install it?

“The overall planning for our projects is showing no major issues,” Scherbring said. “The implementation of some projects is running into major weather delays for the tower crews, some vendor-delayed shipping issues, and in some cities major delays with local zoning permits.”

The NAB keeps its eye on the big picture across the country. Dennis Wharton, executive vice president of communications for the NAB, said that he is giving special attention to project timing—especially in the latter stages of the work.

“We remain concerned that the 39-month timeframe created by the FCC is simply insufficient to accommodate all the stations that have to be moved,” Wharton said. “It’s going to be especially difficult for stations in later phases that may not have already contracted for repack work. The tragic loss of four talented tall-tower workers reduced an already small pool of qualified tower dogs. In addition, the first couple phases have fairly long transition periods—132 days in the case of Phase 2. However, Phases 3 and beyond are very compressed—just 34 days in Phase 5—and any unexpected delays will affect scheduling like a stack of dominoes.”

Wharton also noted that many stations are linked with one or more other stations and cannot transition until those other stations have also transitioned. And due to cold weather and dangerous weather conditions, there are only so many months of the year that tower work is feasible in the northern states.

NEXT GEN TV

In the past couple of years, there has been a lot of discussion of ATSC 3.0 and Next Gen TV, and stations across the country are keeping this in mind now that repack work is upon them.

“I believe many stations being repacked will upgrade to equipment that can more easily transition to Next Gen TV,” Wharton said. “Some of this new equipment can move from the current standard to Next Gen TV transmission with the flip of a switch, so it does present an opportunity for stations to upgrade for the future.”

Sinclair Broadcast Group has been a avid proponent of ATSC 3.0, so the question came up as to what the company might be doing for the repack to prepare for an ATSC 3.0 future.

“Sinclair has maximized stations’ signal reach and included some vertical polarization elements in all the new antennas that are being purchased,” Scherbring said. “This will enhance ATSC 3.0 [operations], but the costs of these items are not reimbursable, so they are an extra cost to each station.”

STILL NOT CLEAR

There’s no question that the channel auction and repack is big—really big. In addition to the repack at full-power stations (which is fairly well known and documented), the FCC said that the number of affected low-power, translators and FM broadcasters is still not clear.

“We do not yet know how many FM or LPTV and translator stations will be affected by the repack,” the FCC’s Kiddoo said. “To date, construction permits for more than 1,500 of the roughly 2,100 LPTV/translator stations that filed applications in the special displacement window have been granted. The Notice of Proposed Rulemaking that the commission adopted in early August sought comment on eligibility requirements and reimbursement procedures for those FM and LPTV/translator stations that incur costs as a result of the repack.”

Therefore, it remains to be seen exactly what the costs and time schedule will be to complete all repack work. In the meantime, work is proceeding quickly across the country.

When asked if the repack was a good thing or just another regulatory nuisance, one broadcaster replied philosophically.

“We can all be armchair quarterbacks on Monday morning,” Sinclair’s Scherbring said. “These are the new rules we broadcasters must live with—we will make it happen.”

For all the latest news and insight on the repack, visit our repack silo.

CINCINNATI—GatesAir last week announced shipment of its 100th TV transmitter as part of the FCC-mandated repack of television spectrum to Hearst Television’s WMOR-TV in Tampa, Fla.

The station, which is taking delivery of a high-power Maxiva ULXTE liquid-cooled transmitter, is one of 13 Hearst Television stations GatesAir is supplying under an exclusive agreement announced in December 2017.

WMOR, destined for UHF channel 18, is installing a ULXTE-100 transmitter capable of 62.9kW. Initially, the station’s transmitter will operate at 58.9kW TPO, allowing headroom for future digital services. The station operates from Riverview Antenna Farm, which is owned by America Tower.

The FCC has assigned the station to Phase 5 of the repack, and Hearst VP of Engineering Martin Faubell has worked closely with GatesAir to make sure the new transmitter is delivered and installed to meet the phase deadline. According to Faubell, the performance of GatesAir during the initial repack phases has been critical to the station group meeting its assigned deadlines.

“We started working with GatesAir very early in the planning process with the knowledge that repack was going to be a serious challenge for Hearst Television, as well as the broadcast industry at large,” said Faubell.

So far, Hearst has taken delivery of five transmitters for stations being repacked. WTAE in Pittsburgh was the latest Hearst station to go on air with a new Maxiva transmitter. That station is not transmitting on channel 27.

The solid-state GatesAir Maxiva transmitters offer several benefits, said Faubell. “Solid-state technology has improved to the point where excellent efficiency is possible with high-power UHF transmitters,” he said. “With GatesAir’s Maxiva transmitters, the reliability will be higher, and the maintenance and power consumption in our facilities will be lower.”

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

As the Nov. 30, 2018 deadline for stations assigned to Phase 1 of the FCC’s Incentive Auction approaches and stations complete plans for the transition to their new channels, I thought other broadcasters and viewers may be interested in the signal levels I’ve been using to compare coverage from different facilities and optimize antenna designs.

During the transition, many stations will be forced to use auxiliary facilities with reduced ERP, lower height or both, which will impact their coverage while their main antenna is replaced with one for the new channel.

I’ve been working on methods for mapping the coverage loss from auxiliary facilities. I’ll describe one of them here.

REQUIRED SIGNAL LEVELS FOR RELIABLE RECEPTION

Outdoor antennas are now a rare sight compared to 50 years ago, although indications are that interest in them is increasing. For most over-the-air TV viewers in and around urban areas, indoor antennas are more popular.

Some studies have been done to determine the field strengths required for indoor reception. One I’ve relied on was presented several years ago based on field measurements by consulting firm Meintel, Sgrignoli & Wallace (MSW). It showed a field strength of 75.5 dBμV/m, on average, was needed for UHF TV indoor reception.

I use that number in my coverage comparisons, but also check coverage at a higher field strength, 88 dBμV/m, for what I call “easy indoor” reception. An “easy indoor” level means the viewer doesn’t have to spend a lot of time optimizing the antenna location or orientation in order to be able to receive the station. This number provides over 10 dB extra margin compared to the MSW findings and is 40 dB greater than the level required for FCC “Community Grade” DTV coverage.

I use a field strength halfway between the 48 dBμV/m FCC Community Grade level and the 88 dBμV/m “easy indoor” level for what could be called “easy outdoor” or perhaps “indoor with effort” coverage. This signal level takes into account the loss from outdoor antennas lower than 30 feet used in the FCC planning factors, and allows for some loss for antennas installed in attics or sub-optimum locations. It can also work for indoor reception if the antenna is in a window facing the right direction and high enough to clear nearby obstacles outdoors.

While these numbers were originally designed for UHF, I’ve been using them for high-VHF coverage as well. Even though the FCC service contour for high-VHF uses a signal level 5 dB lower than that for UHF, VHF reception is usually more challenging, especially for indoor reception, due to RF noise in the house and lower antenna gain.

“Channel 48 Main Coverage Thresholds” (Fig. 1) shows Washington D.C.’s WRC-TV main transmitter facility coverage plotted with these thresholds. Green areas are “easy indoor,” above 88 dBμV/m. Yellow-green areas extend indoor coverage to the 75.5 dBμV/m field strength. The blue areas are those where the predicted field strength is between 68 and 75.5 dBμV/m. Finally, the purple areas extend coverage to the FCC noise limited threshold. Cells with no service due to signal level aren’t shaded and cells with interference (there are 33 of them) are red. This map was created using the “coverpts.shp” files from TVStudy and the open source QGIS GIS.

A simpler way to find a station’s predicted field strength at a location is to use the FCC’s excellent DTV Reception Maps at www.fcc.gov/media/engineering/dtvmaps. Enter a zip code or more precise location and click on the station’s call sign for the predicted field strength from that station. This page only displays the facilities currently on the air.

To see a “rainbow” coverage map for any FCC authorized or applied for facility, use RabbitEars at www.rabbitears.info. Enter the call sign of the station on the first page; scroll down until you see the details on the station; click on “Technical Data” and then “RabbitEars TV Query.” On the new page, scroll down to the facility you want and click on “Longley-Rice Coverage Map” at the bottom of the technical details. RabbitEars is more generous than I am, considering signal levels above 80 dBμV/m “easy indoor” and above 51 dBμV/m “easy outdoor.” (Fig. 2.)

The TV Fool website provides many options for displaying signal power in dBm and noise margin in dB on maps and in tables. Using these values instead of field strength makes it easy to calculate the impact of adding antenna gain or amplification on reception. In many cases, however, adding an amplifier will increase the noise and interference along with the signal level and provide no benefit or even worse reception.

Measuring signal level can be done using any number of signal strength measurement instruments.

A bit of time with your favorite search engine will turn up several options. I’m not going to describe them this month, but will provide a tip on an easy and inexpensive way to measure a TV signal’s power in dBm. The Hauppauge WinTV dualHD USB tuner uses a Silicon Labs Si2157 tuner. The Linux “dvb-fe-tool” will display the signal power in dBm of the station currently tuned to in another program, such as Kaffeine, when run as “dvb-fe-tool-m” in a terminal. The program is available for Ubuntu in the “dvb-tools” package. It is also possible to derive MER (Modulation Error Ratio) from the WinTV dualHD using the “femon” command line program, but I haven’t verified the accuracy.

COVERAGE LOSS FROM TEMPORARY REPACK FACILITIES

Many stations will have to use auxiliary or interim facilities while doing antenna and tower work necessary to switch to their new channels. Stations not changing channels on a tower with stations changing channels are likely to be impacted as well. I’ve been looking at some methods to visualize the impact of the use of these facilities on viewer reception. I recommend stations begin operation on their new channel at full power to insure viewers catch the channel during the market rescan even if this results in coverage loss on the original channel prior to the transition.

The map “Channel 48 Aux Facility Coverage Comparison” (Fig. 3) is an example of a comparison of the main WRCTV facility and the auxiliary WRC-TV facility. Areas where the signal levels from the aux facility are within 6 dB of the main facility or equal to greater than 88 dBμV/m are shown in green.

Areas where the aux facility is over 12 dB weaker than the main facility are shown in gray. In these areas viewers are likely to have more difficulty seeing the aux facility, perhaps requiring an outdoor antenna if they weren’t using one before or upgrading an existing one.

Finally, areas where the main facility has FCC predicted service and the auxiliary facility does not, either due to signal below threshold or interference, are shown in red. For details on how to create such maps, see my article in the fall 2018 edition of IEEE Broadcast Technology or contact me.

If your TV station is operating at reduced power or on an auxiliary antenna during the repack process, I’d be interested in your opinion on whether the thresholds I’ve used for this analysis match your real-world experience. The example I used in IEEE Broadcast Technology had a narrower threshold (+/–3 dB) for equivalent reception since I’ve heard very few viewer complaints when a station has had to go to 50 percent power. Is 6 dB too generous?

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

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

WASHINGTON--The Federal Communications Commission today proposed rules to reimburse some low-power TV stations, TV translators and FM stations for costs resulting from the 2017 spectrum incentive auction, following up on a recent Congressional directive known as "The 2018 Reimbursement Expansion Act."

The act “expanded the list of eligible entities to include LPTV, TV translator and FM stations, provided additional funds to be used for this purpose, increased the funds available to reimburse full power and Class A stations and MVPDs and provided funds to be used for consumer education purposes,” the FCC said today. The statute also created a deadline of March 23, 2019, for the commission to adopt a Report and Order.

According to the NPRM (MB Docket No. 18-214; GN Docket No. 12-268), reimbursement will be available for LPTV stations and TV translators, “if (1) they filed an application during the commission’s Special Displacement Window and obtained a construction permit, and (2) were licensed and transmitting for at least nine of the 12 months prior to April 13, 2017.”

[Read: FCC Will Open April Window For Auction-Displaced LPTVs]

Additionally, the order says the Media Bureau should engage a third-party contractor to assist in the administration of the fund and also directs the bureau to determine cost eligibility and the reimbursement process. However, “the Media Bureau will consult with the Office of General Counsel and the Office of the Managing Director,” the order says.

The order also shares plans to use the $50 million provided by the REA for consumer education. According to the order, the commissioners “anticipate, among other initiatives, hosting a dedicated consumer service call center to provide consumers technical support and assistance on such matters as rescanning and other means to resolve potential reception issues. We also intend to perform targeted outreach to specific communities about rescanning, and we may use advertising spots to disseminate rescanning information. Consumer education funding could also be used in developing additional online resources...”

The NPRM also notes that the additional REA funds must be used no later than July 3, 2023.

FCC Chairman Ajit Pai said, “I’d like to thank Congress for passing legislation which provides additional reimbursement funds for full power and Class A stations, reimbursement funds for newly-eligible LPTV, TV translator, and FM stations, and funds for the commission to use for consumer education purposes.” Pai also thanked the commission staff who worked on the notice.

In his own statement, Commissioner Michael O’Rielly emphasized that he agrees with the reimbursement plans in general but thinks further input is needed before action. Specifically, he said, “While Congress carefully outlined how it intended FY18 monies to be spent, it provided less clarity for FY19. Should these funds be allocated similar to FY18 funds? Should television stations have priority? The answers to these questions will affect how interested parties are reimbursed for relocating during the repacking process...”

Additionally, O’Rielly questioned the validity of the “graduated reimbursement system” based on the idea that time equals money and asked for feedback and alternative proposed system(s) to allocate money.

O’Rielly also cautioned that the educational efforts should not duplicate “efforts undertaken by broadcasters or other stakeholders, or take on initiatives outside of [the commission’s] expertise, such as producing advertising spots.”

Finally, O’Rielly wrote, “I support edits in this item that will mitigate the use of delegated authority, as well as remove the tentative conclusion that third parties who made funding arrangements with LPTVs prior to the passage of REA are ineligible for funding.”

Commissioner Jessica Rosenworcel did not release a statement, but the Notice of Proposed Rulemaking and Order (FCC 18-113) indicated her approval and that of Commissioner Brendan Carr, whose statement was still pending as of writing.

[Read: FCC Allocates Additional $742 Million For Repack Expenses]

The NPRM “tentatively concludes that both full power FM stations and FM translators that were licensed and transmitting on April 13, 2017, using the facilities affected by a repacked television station, are eligible for reimbursement.” This includes “FM stations that incur costs to permanently relocate, temporarily or permanently modify their facilities, or purchase or modify auxiliary facilities to provide service during work on a repacked television station’s facilities.” Also, the NPRM recommends that the reimbursement process be “substantially similar to” that already used to reimburse full power and Class A licensees and MVPDs.

NAB Executive Vice President of Communications Dennis Wharton released a statement saying, “Earlier this year, Congress wisely authorized additional funding to ensure that tens of millions of Americans will not lose access to news, entertainment and lifeline information during the broadcast industry ‘spectrum repack.’ NAB is encouraged by the FCC proposal adopted today that closely mirrors the intent of Congress. NAB will be actively engaged during the rulemaking process to preserve live and local broadcasting on hometown radio and television stations, low power TV stations and TV translators."

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

RAYMOND, MAINE--Like the island itself, many of Puerto Rico’s TV stations continue to deal with the devastation created by Hurricanes Irma and Maria, which struck about one year ago.

To relieve Puerto Rican TV broadcasters from working to put their RF infrastructures back on air only to face Phase 3 or Phase 10 repack do-overs of the work, the FCC amended its spectrum repack transition phasing to assign a pre-Phase 1 deadline of Aug. 1 to these broadcasters.

[Read: FCC Allows Early Repack In Puerto Rico, U.S. Virgin Islands]

To assist these broadcasters, antenna manufacturer Dielectric has expedited orders from Puerto Rican broadcasters for 11 antennas, 10 of which are being used for the spectrum repack. The eleventh is replacing an antenna damaged in the hurricanes, the company said.

The antennas, which include top-mounted and side-mounted primary antennas, are in various states of manufacturing and shipping, Dielectric said. Among them are mid- to high-power TFU series UHF antennas and low-power TLP series antennas. The company is also providing RF filters and components to OEMs for these antennas.

Although Dielectric has two antenna plants with broad manufacturing capability, logistical challenges are bound to surface when there are close to 500 other repack antennas the company has contracted to build, said Jay Martin, Dielectric vice president of sales.

“However, that isn’t going to stand in the way of helping our friends in Puerto Rico. We proactively reached out to them to find out what they needed, and we’ve been diligently generating technical proposals for antenna systems that address their unique needs, such as withstanding Category 5 force winds and other extreme weather conditions,” he said.

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

SOUTHWICK, MA—WGBH Educational Foundation has ordered two new VHF Parallax liquid cooled DTV transmitters from Hitachi Kokusai Electric Comark LLC for its WGBH Boston PBS station and the WGBY PBS station in Springfield, Mass. Both stations are in the process of a post-spectrum auction channel repack.

At WGBH, Comark will supply a multicabinet Parallax VHF band 1 liquid cooled transmitter on channel D5. The transmitter is designed for initial operation at 7.5kW TPO but allows for future power upgrades up to as high as 55kW should the station decide to maximize their ERP in the future. The transmitter cabinets will be pre-wired to facilitate a quick upgrade with additional power amplifiers and PA combiners.

In addition, Comark will supply another Parallax VHF band 3 transmitter on D13 for WGBY. The WGBY transmitter will be configured for 1+1 redundancy with a main/standby configuration. Each half of the transmitter can fully supply the required 13kW TPO with custom RF switching between transmitter cabinets. Both cabinets will be pre-wired to accommodate future power upgrades.

Comark will manage all aspects of both transmitter installations including program management, equipment delivery, on-site installation, and proof-of-performance testing. Both transmitters are fully upgradeable from ATSC 1.0 to ATSC 3.0 due in part the EXACT-V2 exciter technology.

[Read: Maryland Public TV Chooses Comark Parallax UHF TX]

“We expanded our Parallax product line from UHF to VHF band 3 and most recently to cover VHF Band 1” says Dick Fiore, President and CEO of Hitachi Kokusai Electric Comark, LLC. “WGBH/WGBY has been a long standing customer of Comark for many years, having previously purchased their original UHF DTV rigs from the transition from analog to digital. We are very pleased to be working again with WGBH Educational Foundation on this exciting project.”

“WGBH is looking forward to continuing our long relationship with Hitachi-Comark” says Emeric Feldmar, Director of Engineering at WGBH. “We have received excellent products, and support throughout the years. We purchased these Parallax VHF band 1 and band 3 transmitter systems for our WGBH and WGBY facilities that are being upgraded as a result of the spectrum auction/repack with capability to upgrade to ATSC 3.0.”

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

SOUTHWICK, MA.—Maryland Public Television has ordered a Comark 75kW Parallax UHF transmitter for its WMPT site serving central Maryland, Hitachi Kokusai Electric Comark said last week.

“Comark worked with the management of Maryland Public Television to provide a complete solution for their repack requirements,” said company President and CEO Dick Fiore.

The transmitter consistS of three rack cabinets. Each has 16 UHF Asymmetric Broadband Doherty power amps providing up to 75kW TPO. The liquid-cooled transmitter will be equipped with dual Exact-V2 exciters in a main-standby configuration and an RF mask filter system inclusive of Magic Tees combining each cabinet, the company said.

[Read: Meredith Preps For Repack With Comark Parallax Transmitters]

Comark will manage shipment, offloading and placement of the new transmitter as well as remove the station’s existing DTV transmitter.

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

It’s a given that there is going to be considerable “channel shuffling” after the upcoming television broadcast spectrum auctions. There also will be a lot less in the way of channel slots to choose from in the subsequent station repacking action. In 2014, the FCC adopted methodology for predicting interference between TV broadcasters and broadband wireless transmitters that are operating either in co-channel or adjacent-channel frequency slots. The commission termed their interference-prediction methodology, which is based on the Longley-Rice propagation model, “ISIX.”

Fig. 1: Derived from Fig. 23, page 453 of FCC document 14–50 dated May 15, 2014 by Stanley Knight
Click to Enlarge Looking at some cases where ISIX interference cases may come into play, suppose your station were to be allocated Channel 28 (center frequency = 557 MHz) in Scenario 7 (see Fig. 1). Your general manager might ask you to become a fortune teller and tell him whether this is a robust channel or a not so robust.

An ISIX interference situation may result if there two strong signals whose center frequencies are F1 and F2 and your center frequency is below F1 by the difference in frequencies F2–F1. IM3 falls in Channels N and N+3, if there are strong undesired signals on Channel N+K and N+2K. (K is an integer, either positive or negative).

For example, if there is a signal on Block A 619.5 MHz, (N+K) and a second signal is centered at 682 MHz, (N+2K) then F2–F1 = 62.5 MHz. Subtracting 62.5 MHz from F1 = 557 MHz, the center of your channel.

In this example F1 is in the blue area, meaning F1 is being radiated by a base station. F2 is in the yellow area, meaning this signal is being radiated by a cellphone.

INTERFERENCE CAUSES NOT ALWAYS APPARENT
Base stations radiate most of the time and their effective radiated power (ERP) approaches 1,000W. Cellphones briefly transmit and their ERP is less than 23 milliwatts. ISIX interference may result only when both F1 and F2 are transmitting simultaneously. Moreover, in this example F2 will be strong only if the cellphone is extremely close to the DTV receiving antenna. If either F1 or F2 is not strong, there can be no ISIX. However there are many base stations serving a given community, and many base stations will be found near interstate and other major highways.

Many viewers rely on an indoor antenna so your received signal power from these indoor antennas may be quite weak even when the receiver is not near your noise-limited coverage perimeter. Base stations are generally only a few miles apart. Therefore ISIX may be found around base stations.

While the first 600 MHz auction will auction 5 MHz blocks, after that most successful bidders will have acquired two or more blocks of 600 MHz spectrum. I expect that many of them will bid for contiguous blocks of 600 MHz spectrum so that they wind up with 10 MHz “super blocks,” which will be far more profitable than individual 5 MHz Blocks.

Fig. 1 shows that the spectrum for uplinks and down-links are equal for a given scenario. For Scenario 7, there are seven 5 MHz blocks for uplinks (cellphone Tx) and seven more for down-links (base station Tx).

This would allow up to three 10 MHz super blocks plus one 5 MHz block; or two super blocks and three 5 MHz blocks; or one super block and five 5 MHz blocks. For example, there could be three super blocks: A*B, C*D, E*F and one 5 MHz block, G. Or there could be super blocks B*C, D*E and F*G with one 5 MHz block A. There are many other combinations of 5 MHz blocks and super blocks 10 MHz wide.

The LTE signal bandwidth is 4.5 MHz for a 5 MHz block, and it will be 9 MHz for a super block of 10 MHz width. This means that the effective radiated power of a super block of 10 MHz is 3 dB greater than for a 5 MHz block. There is another subtle difference between the 5 MHz blocks to be auctioned initially, and 10 MHz super blocks. ISIX interference generated in a receiver is spread over 3*4.5 = 13.5 MHz. A 10 MHz super block will generate ISIX interference spread out over 27 MHz.

So the problem of ISIX interference to the reception of an ATSC signal will be far greater with super blocks (10 MHz wide) than with 5 MHz blocks for these reasons. However the FCC does not consider ISIX except for co-channel interference (CCI) or adjacent channel interference (ACI). Broadcasters should be concerned with the fact that ISIX interference can arise from signals offset in frequency by more than 6 MHz because the FCC will not consider offsets between DTV signals and LTE signals greater than 6 MHz. Two super blocks of 10 MHz each may generate third-order distortion products spanning 27 MHz! This is well known, but not recognized by the FCC as causing “harmful interference.” Where it happens the affected receive cannot look to the Commission or broadband operators for relief. This was pointed out in my June column “FCC ‘Harmful Interference’ Definition Gives Wireless a Pass” on www.tvtechnology.com.

ANOTHER INTERFERENCE EXAMPLE
Looking again at Fig. 1, you will note that the frequencies of LTE signals for a given block vary with the scenario number. Therefore you will need to know what blocks will be radiating LTE signals in your community. Whether the FCC will identify the scenario it applies for your market and your new channel number or just your channel number remains to be seen.

We will start with super block D*F whose center frequency is 639 MHz. F2 = 639 MHz. F1 is equally distant between Channel 28 and the center of super block E*F. So F1 = 0.5(639–557) = 598 MHz. This is in the green portion of the 600 MHz band, which for Scenario 7 is a TV channel (Channel 35). So here we have a hybrid of undesired signals, one LTE signal on super block E*F and DTV signal on Channel 35. Channel 35 will not cause CCI or ACI to Channel 28, so it is quite probable that there may be both Channels 28 and 35 in the repacking scheme for your community. But, there also may be ISIX to your Channel 28 signal from this combination of super block E*F and Channel 35 signals, however the FCC does not recognize such interference as being harmful interference.

With these facts, you will be able to answer questions about how your station will fare after repacking.

Charles Rhodes is a consultant in the field of television broadcast technologies and planning. He can be reached via email atcwr@bootit.com.