ATLANTA—Georgia Public Broadcasting (GPB) operates a state-wide PBS TV network using nine full-power DTV stations and a handful of low-power translators. All but two of our high-power stations were already using high- band VHF channels prior to the FCC repack, so it was reasonable to assume most of these stations were safe from having to move from the pre-repack channels to new ones. 

As luck would have it, five of the state’s seven VHF stations were repacked and therefore required new transmitters. Two of our stations that operated on UHF channels opted to sell their spectrum and switch to VHF low-band (WJSP and WNGH).

TALKING OUT OUR NEEDS

GPB only had one DTV station in the early phase of the repack (WJSP). We thought air-cooled transmitters would be the best way to move forward so we ordered a 12kW air-cooled unit from Hitachi-Comark for this station on VHF Channel 5. We also looked at the remainder of our station’s requirements for repack, most of which were in the later phases of the process. Upon further discussions with Hitachi-Comark, we chose the company’s Parallax liquid-cooled DTV transmitters to satisfy our remaining requirements.

Hitachi-Comark’s Parallax series offers several advantages, including high efficiency, minimal requirements for in-building air conditioning and low acoustic noise levels inside the transmitter facilities. We ordered the balance of our repack DTV transmitters from Hitachi-Comark and swapped out the original air-cooled transmitter at WJSP for a Parallax liquid-cooled replacement.  All of the Parallax transmitters deployed use a single cabinet design, varying from 4.3kW “V3” (three PA’s) through 15.9kW “V11” (eleven PA’s). Each transmitter is paired with a separate indoor cooling module with dual pumps and an outdoor dual-fan liquid-to-air heat exchanger.

THE INSTALLATION

Field deployments went very smoothly. Hitachi-Comark assigned a program manager who oversaw our entire project from start to finish. First, they performed comprehensive site surveys at all our transmitter facilities to ensure all details were documented prior to actual on-site work. New transmitter equipment and associated accessories were deployed systematically to each repack transmitter site directly from the vendor’s facility. Hitachi-Comark’s installation crews were highly professional and extremely efficient with their on-site work.  

One of our most difficult site locations was WGTV, with a transmitter facility located on top of Stone Mountain Park. The mountain has an elevation of just under 1,700 feet AMSL—great for broadcasting, but difficult and highly dependent on weather conditions to access. Additionally, we could not modify the building to accommodate new equipment.

We installed two new Parallax transmitters (main and standby) in the basement of the building at WGTV. Each transmitter included a separate cooling system for complete redundancy. Speaking of cooling systems, the outdoor heat exchangers needed to be mounted to the roof of the building—three stories above the transmitters. Hitachi-Comark even designed and supplied a custom mounting frame for both heat exchangers, utilizing existing mounting points from the previous analog systems. It was also extremely difficult to route the interconnected cooling system hoses between the outdoor heat exchangers and the indoor equipment.

Even with all these constraints, the team at Hitachi-Comark did a great job. They delivered the equipment on time and on budget. We are glad we chose to work with Hitachi-Comark, and would recommend them to anyone looking for new equipment and field services.

Adam Woodlief has served as the chief technology officer for GPB since 2018. He currently serves on PBS’s Engineering Technology Advisory Committee (ETAC) and is co-chair of the ETAC Public Safety working group. He can be contacted at awoodlief@GPB.org.

For more information, visit www.comark.tv or contact 800-345-9295. 

As the need for specific audio and video format conversions has increased, so too has the demand for engineering flexibility and processing speed during studio and remote productions. In many instances the studio or truck will often have a collection of video frame syncs and converters at the ready. While these devices are historically thought of as video processors, they can also usually convert audio as well. One such device is the AJA FS2 Frame Sync and Video Processor.

At Georgia Public Broadcasting, under the leadership of Chief Technical Officer Adam Woodlief, we recently redesigned our control rooms to focus on enhancing performance and flexibility to meet growing production demands (Fig. 1). As part of the process, we discovered a need to originate AES-based audio from embedded HD/SDI video sources.

In addition to the AES audio needs, color correction capability was also specified for two video channels of the production control room graphics system. With these specific needs, and in large part due to a surplus availability, the AJA FS2 unit was implemented for both audio and video processing without the need for additional hardware.

In Fig. 2, a block diagram from the FS2 manual shows two independent processors for video and two processors for audio, which can both push AES or analog audio. When using the AES option, the Audio 1 processor is set up to pass either analog or AES. Unlike the video processors, the audio processors can pass converted audio from more than one source at a time—this capability is often overlooked when the focus is strictly on video.

On the back panel of the FS2, a DB-25 AES output connector will allow eight (2) channel AES output groupings of either or both SDI input channel combinations.

It is important to note that there are two separate processor blocks in the block diagram and that the processors are not fixed to a specific input channel. The Audio Input Crosspoint matrix allows audio associated with either SDI input channel to be mapped to the AES/EBU output port on the rear DB-25 connector by way of the Audio Output Crosspoint Matrix.

For our conversions, we used the Audio 1 processor to deliver AES audio associated with each of the two graphics video channels. A key point when configuring is to select the Audio Map parameters and map both the SDI 1 and SDI 2 input embedded audio sources via the “Audio 1” processor (Fig. 3). These assignments can be made by accessing the Audio 1 processor either by front panel access or the browser-based GUI.

In the “Audio 1” menu settings, go to Menu Sub section 1.17 on the front panel, Audio1 Map Ch 1/2, and select SDI1 Ch 1/2.

Next, go to Menu Sub section 1.18 Audio1 Map 3/4 and select SDI2 Ch 1/2 (Fig. 4).

Once these changes are made using either access method, there will be two independent SDI-based AES channel subgroups; Ch 1/2 from the SDI1 Video source, and Ch1/2 from the SDI2 video source. These four collective AES channels are output to the DB-25 (Fig. 5.) on the corresponding Ch 1/2 and Ch 3/4 (three-pin) groupings.

Using the FS2 in our facility allowed us to configure our AES audio channels to serve as two independent stereo audio channels for both graphics video output channels, with the ultimate result being the delivery of video- and audio-processed signals from one box. The AES signals were then distributed to a 1RU Wohler AES audio monitor at the graphics operator station in the control room, and to a Studer Vista 9 series audio console via a digital I/O unit. The color corrected SDI signals from the graphics system were further distributed for use elsewhere in the facility via HD routing. Initial setup of the FS2 unit via front panel access is shown below in Fig. 7.

The resulting output on the Studer audio console corresponds to two (2-channel) AES groups. Fig. 8 shows both a 1 kHz audio signal originating from a test unit as well as a second audio signal from an independent SDI source.

The desire to streamline engineering often drives integration of signal processing into a single unit, resulting in fewer components and lower costs. Organizations like Georgia Public Broadcasting can realize enhanced performance and flexibility while achieving critical cost savings using this approach. 

Daniel Hall is a broadcast engineer with Georgia Public Broadcasting.

ATLANTA—Georgia Public Broadcasting (GPB Media) is the state’s leading provider of public media on television, radio and digital platforms. We operate nine TV stations and 18 radio stations and recently won “Station of Excellence” at the Southeast Emmy Awards for the third time in 2017.

Our most valuable things are the assets and content we create. As a multifaceted network with multiple platforms, it’s paramount for us to control content and ensure collaboration and continuity across all platforms. To augment audience experience and sustain our growth in an ever-evolving media landscape, GPB Media decided in 2016 to replace its aging broadcast infrastructure of siloed production, post-production and playout systems, which required significant resource time to operate and support.

We set out to source an efficient, versatile and IT-friendly broadcast solution to connect our existing systems, streamline operations and scale according to our needs and future requirements, all within a public broadcasting budget.

The Dalet NewsPack solution made GPB’s newsroom production tools and archived content available in a single location.

A CENTRALIZED SOLUTION
Following an in-depth search, we selected Dalet’s end-to-end, story-centric workflow that integrated our existing systems, centralizing all GPB video and audio assets on one single and collaborative platform. We deployed the Dalet solution in a phased approach, starting with a pre-configured newsroom system and then expanding to include end-to-end content production, distribution and eventually, archive management.

Prior to Dalet, we had no native ingest and playout capabilities, requiring us to manually manage news and program content ingest and playlists. The newsroom playout workflow required operators to manually control insertions from different servers and tape decks. With no centralized content pool or rich search capabilities, it was difficult to locate and use our high-value assets in an efficient manner.

Our first move was to install the preconfigured Dalet NewsPack solution, which included a media asset management system, integrated newsroom computer system and ingest and playout management. Dalet NewsPack integrated our existing graphics, prompters, storage, trafficking and postproduction components, connecting key systems to create a fluid workflow for us to track news events with the corresponding media, teleprompter text, storyboards and final production within one searchable media asset. Dalet NewsPack also included the Dalet OneCut multimedia news editor, enabling the storyboarding and cutting of story packages with both assets and capabilities readily available.

The Dalet Galaxy MAM platform gave us extensive metadata capture and customization. With search and retrieval capabilities, we were able to reinvigorate content use across the operation. Dalet also allowed us to streamline the closed-caption workflow by extracting closed captions as metadata, making them indexed and searchable. Operators can edit and adjust captions as needed and either export or insert into media, or overlay on the video player.

EXPANDING SCOPE
Based on the success of the initial deployment, we expanded the scope of the implementation to improve content publishing and distribution as well as support additional third-party integrations. Dalet is very scalable, so it was straightforward for us to expand the platform without having to re-install an entirely new solution.

We integrated an ENCO system for radio automation as well as incorporated new distribution targets. The integration allowed us to playback and preview our audio files and include them in the rundown and scripting. The expansion also allowed us to create migration policies for distributing content. We created a mezzanine format and automated the distribution workflows to the Syracuse, N.Y. joint master control, PBC Cove and social media outlets. This was a big productivity gain for us.

Debra Gilbert is the enterprise program and information technology manager at Georgia Public Broadcasting. For more information, please contact Debra Gilbert atdgilbert@GPB.org.

For more information, please visitwww.dalet.comor call 212-269-6700.