As the transition to digital television continues, the television transmission facility has grown to accommodate the addition of another “channel” to the broadcast plant. Engineers today are responsible for maintaining an analog transmitter, the analog backup, the DTV transmitter and, eventually, a DTV backup and all the auxiliary digital equipment. This is in addition to taking care of all the transmission site equipment – tower lights, HVAC, security systems, etc. – often in a distant location. It is no wonder that the need for more flexible and robust remote control monitoring equipment is growing.
Figure 1. The Harris eCDi performance monitoring screen provides remote monitoring of 8-VSB signal quality. The Web interface provides transmitter status and control in addition to performance monitoring for all Harris digital television transmitters.
Traditionally, remote control stood for a one-on-one relationship between the transmitter and monitoring equipment tethered by parallel connections and a phone line at the site. This later evolved into troubleshooting for a limited number of parameters, but these systems had a limited number of access options and very few ways to actually exploit the information to pinpoint failure points or problems.
Transmitter control is evolving to include a network transaction using a Web interface system with a dedicated server to port transmitter information to a remote computer. Server style varies, depending mainly on the control system characteristics of the transmitters. On some systems, Web servers are available that are integrated within the transmitter by way of off-the-shelf industrial PLC systems used for control. These systems communicate basic graphics and system information using pure HTML for transmitter control.
A new breed of add-on transmitter Web servers was announced recently by a number of manufacturers. An example of this is the Harris eCDI Web interface, shown in Figure 1. These servers interface to the transmitter and exciter(s) serial interface and serve the information to a standard Web browser. The Web interfaces for these transmitters lend themselves to more sophistication, with at least one using a Java environment with graphics and XML for data transfer, saving the more basic HTML for setup and login functions. Some add-on Web servers also provide multi-level control access, SNMP agents for network management, e-mail/pager fault notification, and “microbrowsers” for interfacing to wireless PDAs and Web-enabled cell phones. Due to security concerns, no station to date has implemented wireless control.
Add-on configuration allows manufacturers to create a common interface architecture for all current and legacy products. Commonality of interfaces helps station personnel that are familiar with one transmitter navigate the interface of another, less familiar piece of equipment. This would come in handy when installing a new digital exciter or taking care of a collocated FM when the transmitter supervisor is on vacation. This commonality also becomes extremely important with facilities containing multiple transmitters of different architectures, such as a solid-state VHF analog and an IOT UHF digital.
All stations are sensitive to network security and only the bravest (read: foolhardy) are willing to put transmitter control on an open Internet connection. Luckily, an effective solution is most likely already installed on most networks – a virtual private network. These saviors of security are widely used, and an out-of-the-box system can be picked up for a song at any local computer retailer.
At least one manufacturer is taking control and management even one step further and creating a software package with greater breadth of monitoring, allowing multiple users to simultaneously control, monitor and view the status of multiple devices at multiple locations. Centralized monitoring and control solutions from transmitter manufacturers will offer service expertise and insight from the people who know the product best.
Jason Rieg is product line manager for Harris Broadcast Remote Control-eCDI.
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