Stations wanting to convert to ATSC 3.0 have had trouble finding an ATSC 1.0 home for their high-definition (HD) and standard-definition (SD) streams. Using MPEG-4 (AVC) for ATSC 1.0 has been tried but created problems for viewers with older TV sets or old “coupon” converter boxes. I’ll suggest some options that might work, if the FCC allows it.

Finding Space for Homeless ATSC 1.0 Program Streams
There is much support for ATSC 3.0, including recent interest from the U.S. government, which is studying the standard’s Broadcast Positioning System utility as a backup for GPS. New features are being added, including standards based (DRM) radio. Work has started on developing ways for 3.0 to work with 3GPP wireless technology.

While LG is no longer selling ATSC 3.0 TV sets, other manufacturers such as Sony, Samsug, Hisense and now TCL are offering them, and consumers now have a variety of inexpensive set-top box receivers to choose from. Features like virtual channels (delivered by internet to the TV rather than over-the-air) and broadcaster applications that provide additional content and the ability to restart programs (using the internet) will make 3.0 even more attractive to viewers.

However, spectrum and data bandwidth for ATSC 3.0 are limited. Converting existing stations to 3.0 requires finding a home for their ATSC 1.0 programs on the stations remaining on 1.0. The popularity of ATSC 1.0 “diginets” has made it difficult to find a space for a new 3.0 host’s streams. One obvious solution is to improve the efficiency of the existing ATSC 1.0 capacity by using MPEG-4 video, which has roughly twice the efficiency of MPEG-2.

By The Numbers
Table 1 shows an example of average bandwidth allocation for a station carrying two HD streams and four SD streams in their 19.392 Mbps ATSC 1.0 stream. The HD streams are assumed to have a primary 5.1 audio and a secondary stereo audio stream for audio description or second language.

Extra bandwidth is allowed for null packets and PSIP data. Quality will vary depending on program content and use of aggressive statistical multiplexing is required to give an HD stream more bandwidth when needed and let the SD streams have more bandwidth when the HD streams don’t need it.

Early tests used MPEG-4 (AVC) encoding on one or more SD streams. Table 2 shows the result of converting all the SD streams in Table 1 to MPEG-4, keeping the same audio bit rates and reducing the video bit rate to 650 kbps.

That allows equal or greater video quality than a 1,000 kbps MPEG-2 stream. This configuration provides an extra 1,400 kbps of bandwidth, which could be used for one more MPEG-4 SD streams. Reducing the MPEG-4 SD bit rate to 50% of the MPEG-4 bit rate would allow two additional MPEG-4 SD streams at the lower rate.

Unfortunately, attempts to use MPEG-4 have resulted in complaints that the program had audio but no video from viewers with older TVs or NTIA coupon set-top boxes. If there was a way to hide the MPEG-4 content from the older TVs, it would likely eliminate the complaints, but I haven’t found a way to do that. As a result, use of MPEG-4 by full power stations has been limited.

There is a way to add significantly more capacity to lighthouse stations without leaving any viewers behind—transmit the HD content in MPEG-4 with a simulcast in SD in MPEG-2—leave all existing SD diginets in MPEG-2. Viewers with older TVs would not lose any programs, but the main program would be in SD on those sets. This would not matter for anyone using the NTIA coupon set-top boxes as their output is SD only.

Table 3 shows the bandwidth allocation for MPEG-4 only HD and MPEG-2 SD, assuming a 50% reduction in bandwidth for the HD streams compared to MPEG-2. Audio is 5.1 for the MPEG-4 HD streams and stereo for the SD MPEG streams, with room for a stereo secondary audio on the SD simulcasts. This scenario provides over 3,600 kbps of extra bandwidth, enough for three more MPEG-2 SD streams with stereo audio.

Simulcast Issues
If you’re interested in this approach, take some time to build a spreadsheet and test other scenarios. Consider dropping one of the MPEG-2 SD diginets—that would provide enough bandwidth for another MPEG-4 HD and its companion MPEG-2 SD. Another option would be to use stereo audio on the MPEG-4 HDs and a 96-kbps mono secondary audio tracks. With a small reduction in video bandwidth that would also allow an additional HD and companion SD.

Encoder experts may notice a potential problem with the simulcast approach. Statistical multiplexing allocates bandwidth based on stream content and priority. If two streams are airing complex content requiring extra bandwidth at the same time it may limit the bandwidth available to other streams. However, if the HD and SD companion streams can share the same audio (5.1 main and stereo secondary) the bandwidth gained could offset that effect and perhaps work better than delaying the video one of the streams.

The FCC has made it clear they want no viewers left behind. Allowing conversion of HD streams to MPEG-4 while providing an SD stream (with secondary audio and audio description) to viewers with older sets is one way to accomplish that goal. It will require approval from the FCC and likely negotiations with cable companies, if the SD MPEG-2 stream alone remains the “primary stream.”

Ideally, the FCC would consider both streams, MPEG-2 and MPEG-4, if both were identical, as “primary” for regulatory purposes.

Updates
I’ve received emails from readers interested in building the Pi-OTA DTV monitor I described in my November 2023 column at I’ve put all the files and instructions on how to build it on Github at https://github.com/DougLung2000/OTA-Pi-Monitor .

Since publishing the article I’ve made the web server more robust by adding the gunicorn WSGI and modifying the way the displayed data is updated. I also have tested it on the Raspberry Pi 5.

Long time readers will recall that “Kaffeine” was my favorite application for viewing and recording DTV broadcasts on my Linux laptop. Linux distributions are moving from X.org to the Wayland desktop server and Kaffeine does not work under Wayland.

Now I use “w_scan” (available in most Linux distributions) to scan for available channels wherever I happen to be and save them as a VLC “xspf” playlist file. An improved version, “w_scan2”, is available at https://github.com/stefantalpalaru/w_scan2. You can edit the source code to stop it from scanning UHF channels above 36. Load the xspf file into VLC to view the programs and program guides.

VLC allows recording, but I found it easier to install “tvheadend”, also available in most Linux distributions, for recording. It runs in the background as a systemd process and thus I don’t miss as many recordings as I did with Kaffeine.

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

It’s amazing what can happen in just a few years. Not too long ago, ATSC 3.0 proponents and skeptics would go round and round arguing for and against NextGen TV.

But since LG Electronics, Samsung and Sony blazed the 3.0 consumer trail at CES 2020 with their introduction of the first NextGen TVs, the naysayers have had progressively weaker arguments as broadcasters and CE makers alike achieved a succession of milestones on the way to a successor TV standard. Without question, there have been some setbacks along the way, but the direction and momentum are clear.

Perhaps the last bastion for skeptics was datacasting. ATSC 1.0 supported datacasting, but it never lived up to its commercial potential. “Why should it be any different with 3.0?” they would ask.

But as the saying goes, “the proof of the pudding is in the eating,” and with several important datacasting developments at the 2024 NAB Show, reported in last month’s column, it seems 3.0 proponents and skeptics alike are about to get a big spoonful and determine for themselves whether delivery of IP packets via broadcast for third-parties eager to find affordable alternatives to unicast wireless networks is a viable 3.0 business.

Presuming initial rollouts are successful, it’s likely more broadcasters will wish to jump on board, making some of their bandwidth available for datacasting to capture their own slices of the pie.

The problem at the moment is the lighthouse model used for the voluntary transition to NextGen TV leaves only a fraction of the bandwidth potentially available in markets in play for resale to data customers. 

In most markets, broadcasters share single sticks and 6MHz channel assignments to deliver over-the-air NextGen TV. They’ve reshuffled the deck on the remaining towers and assignments to maintain their DTV main channels and digital sub-channels.

The hope is that over time, consumers will replace their existing legacy DTV sets with NextGen TVs, making it possible to reshuffle available TV spectrum periodically, devoting more spectrum to 3.0 service and less to 1.0. Eventually, local broadcasters would end up sharing a tower and 6MHz channel assignment in their markets to maintain legacy DTV service—a nightlight—until consumers replaced the last dribs and drabs of ATSC 1.0 sets in their homes.

The problem is what to do about the Diginets. They require bandwidth. While it’s true broadcasters are only obligated to maintain their primary channel, it’s unimaginable that they would be willing to forego Diginet revenue by shutting them off simply on the hope of 3.0. Not only would station revenue suffer, but it’s highly likely many viewers would be miffed—some to the point of complaining to their representatives and the commission.

However, I can only wonder if 3.0 datacasting revenue potential will prove to be so great that someday broadcasters themselves elect to pay for ATSC 3.0-to-1.0 converters for dwindling DTV viewers. That way broadcasters can complete the transition, maintain their OTA main channels and Diginets for first-gen DTV viewers and maximize the earning potential of their channel assignments by allocating a substantial portion of available bandwidth to meet the datacasting demands of a new group of clients.

RAYMOND, Maine—Dielectric has launched a new filter for broadcasters deploying ATSC 3.0. The new Single Mode Filter targets high-power, single-channel applications and adjacent channel combining. Used as a combiner, the new high-power UHF filter is built for two adjacent TV transmission systems with a capacity of 60 kW TPO per channel and supplies additional power capacity for broadband applications. It can also be used as a single-channel 80 kW reflective filter, making it an economical alternative to the traditional dual-mode Constant Impedance Filter (CIF ) or the repack waveguide tunable CIF. The first orders are in production and ship in October.

The Single-Mode Filter reduces the number of components required for 80 kW applications, according to the company which notes that the innovation uses a reflective design approach versus the CIF approach, which requires two filters and input and output hybrids. The reduction in hardware also reduces the installation footprint — a substantial benefit for broadcasters with limited RF facility space. The fact that the filter is single-mode means it requires very little parts to make it work, which yields reliability for broadcasters.

The timing of the innovation is helpful for broadcasters planning their ATSC 3.0 systems. According to Cory Edwards, Director of OEM, Distributor and Southeast Asia Sales, broadcasters are looking for solutions that can handle more average and peak powers. 

“The ATSC 3.0 standard adds a stronger vertical polarization element than ATSC 1.0 to deliver NextGenTV broadcasts more effectively to mobile devices,” said Edwards. “That ‘V-Pol’ element requires the broadcaster to send more power through the transmitter, which results in a much higher amount of voltage in the first filter cavity. That problem escalates when you start to combine adjacent channels.”

Edwards notes that while the single-mode filters optimize power efficiency for ATSC 3.0 systems, they share the same performance efficiency as Dielectric’s waveguide dual-mode filters.

“The losses in our reflective and waveguide filters are very low across the board,” said Edwards. “The single-mode filter provides a more economical option for very high-power UHF broadcasters, and a more robust solution for ATSC 3.0 systems.”

The Sinclair Broadcast Group station cluster in West Palm Beach, Fla. is a very active campus with four TV stations: WPEC, WTVX, WTCN and WWHB. We also produce newscasts for our sister station WGFL in Gainesville, and are home to the Network Operations Center for nationally distributed Sinclair networks, Comet, Charge! and TBD.

Early in 2022, Spanish language Azteca affiliate WWHB was selected to be the host station for the West Palm Beach market’s NextGen TV rollout. This meant WWHB would transition away from broadcasting in the traditional ATSC 1.0 format and move exclusively to ATSC 3.0. 

While an exciting project to undertake, this would involve many changes in how we deliver content to viewers. Fortunately, we developed a unique partnership among the station groups in our market led by our partners at One Media. 

In collaboration with E.W. Scripps, Gray and Hearst, Sinclair’s WWHB would serve as the host carrying everyone’s main programming. This meant CBS, ABC, FOX, NBC, and Azteca signals would transmit together as never before in the new format.

Transparent to Viewers
Through our partners at LTN Global, all the local stations would send their main program feed to the WPEC facility for OTA transmission. The partnership also included an agreement that traditional ATSC 1.0 programming previously broadcast on WWHB would be shared across those different stations as additional subchannels. Again, LTN Global provided the transport mechanism to deliver our outbound programming to the other stations in the market.

PSIP information remains the same so WWHB’s viewers never know the difference. We control the programming here in the WPEC campus, but the content is transmitted on four different stations in ATSC 1.0 format. Confused? It gets better…

We now needed to monitor our content delivered across multiple stations throughout the West Palm Beach area to maintain compliance and quality control.  Accomplishing that required major changes to our existing receive system.  

Shown below is the station’s tower-mounted receive antenna system. One UHF Paraflector antenna pointing North, a VHF Log Periodic looking South and a smaller UHF Log Periodic also pointed South.

At the studio tower base, all three antenna signals are combined and processed so that a uniform level can be distributed via underground fiber directly to the Master Control Hub for over-the-air monitoring and to our in-house cable system for distribution across the campus.  

This was accomplished using multiple tuned-cavity filters, passive attenuators, and some fancy RF plumbing. Once the signals were filtered and processed, they were fed into an RF signal combiner where they were re-mixed for amplification into the fiber transmitter. 

Not surprisingly, that complicated and unwieldy arrangement was inherently lossy and resembled a science experiment gone awry despite our best efforts at cable management.

'Swiss Army Knife'
As part of the ATSC 3.0 rollout, we were issued a new signal analyzer from One Media—the Hexylon, which is a veritable “Swiss Army Knife” developed by GSERTEL/TELEVES in Spain.  

For us here at WPEC, the Hexylon became a vital tool to analyze, verify and document multiple signals across a wide variety of transmission formats—everything from multicast UDP to STLTP, QAM, ATSC 1.0, as well as ATSC 3.0 and a lot more. Because this was a new piece of equipment, we got factory training from instructor Javier Ruano who showed us how to use its features. 

 That instruction session led to a series of discussions between Javier and the engineers at WPEC. In one conversation, Javier mentioned using AVANT X, a product which sounded tailor-made for our OTA reception challenge. 

I wanted a second opinion, so I called Jon Kipp at TONER CABLE who further explained the features of the AVANT X in depth.  We decided to put it to the test. Senior Engineer Bob Blauvelt and I put the AVANT X through its paces, and we were impressed!

AVANT X can input up to four separate OTA RF signals, along with a dedicated input for traditional QAM cable channels and another for FM radio.  It processes each of those inputs and allows the user to adjust the independent gains and filtering. The user can eliminate unwanted channels, reconfigure channel assignments and selectively adjust overall gain to produce a uniform response across the spectrum.

 The output section boasts a whopping +55dB of gain and is suitable as a launch amplifier. After we benched the unit for a week, we made plans to completely overhaul the receive system and replace all the passive components with the AVANT X. After a few days laying out blank rack panels and punching holes with the drill press, we had all the components mounted and ready to install.

There’s a lot of cellular data and other RF interference in our area, so we added TONER CABLE’s 606 LTE filters to each feed just to be on the safe side. Because we wanted to incorporate signals from the Miami stations, which are 90km to the south, we included a pair of Channel Master preamps to give us better signal-to noise to work with. 

Apart from the front-end gear, all we really needed was the AVANT X. We got rid of all the multiple cavity filters, passive attenuators, and lossy combiners. Installation took just a few hours and immediately eliminated all the reconfiguring, tweaking and downtime required by our previous “science experiment.”  We filtered out and re-introduced two signals out of Miami as a separate input on the AVANT X so we could better align them, and the results were remarkable.

For reference we measured the raw output of each antenna as shown below:

On the studio side, we distribute more than 90 television channels throughout the WPEC campus using our in-house cable system. We modulate our own QAM channels using the Sencore OMNI 16. The channel lineup also includes 50 cable channels from a Vecima Hospitality Encoder provided to us by Xfinity.  

Internal Distribution
With the NextGen TV format now available, we wanted to incorporate the ATSC 3.0 signal for internal distribution to offices and conference rooms equipped with NextGen receivers. Sadly, the frequency for ATSC 3.0 Channel 33 was already in use in the QAM system, so we put a second AVANT X in line. This allowed us to regroom a copy of the ATSC 3.0 signal and slip it between a gap in the QAM signals on Channel 12 as shown below. 

Grooming the ATSC 3.0 Channel 33 to In House Channel 12 resulted in a bit of adjacent channel spillover from active channels 32 and 34. By allowing a 6MHz band on either side of the inserted channel, we were able to avoid any cross-channel interference. The original Channel 33 signal remains unaltered for test and QC on a separate feed, while the new channel copy is inserted into the larger system for distribution throughout the campus. 

Overall, we were highly impressed with the performance and features of the AVANT X. The folks at TONER CABLE and TELEVES have been great to work with and I am grateful to Javier Ruano and Jon Kipp for their help and assistance through the project. The AVANT X has proven to be an affordable, simple and elegant solution for those who need to accurately monitor over the air television signals In a professional or even residential environment.

WEYBRIDGE, ENGLAND & BROOMFIELD, COLO.—Pebble Beach Systems has created a new web-based remote management and monitoring dashboard for its Marina automation environment, Lighthouse. The system provides control, monitoring, media management and system configuration tools through widgets on configurable, web-based dashboards.

Lighthouse

The Lighthouse system is designed for PCs, tablets and mobile devices, built using JavaScript and HTML5 technology. It incorporates its own node.js web server and offers load balancing and high availability for monitoring and access. It also utilizes TSL encryption for protection in the web environment.

Lighthouse can work with multiple Marina systems that are running different software versions and operating at different frame rates. Layouts can be configured based on a user’s roles and switch between different dashboards. The system is also capable of designing, editing, launching and decommissioning virtual IP channels.

Pebble Beach can deploy Lighthouse as a node.js webserver on a Linux operating system, provide host hardware, or implement it as a virtualized infrastructure.