Early in 2020, WAMU completed its new ERI 1183-series FM master antenna system, the largest in Washington, D.C. It serves WAMU, WTOP and WPFW, and is an aux for WETA. The tower also holds separate noncombined antennas for WMMJ(FM) and a backup to WPGC(FM).
Senior Director of Technology Rob Bertrand had been part of the management group for a high-profile master antenna group in another major market, which had experienced some operational challenges over the course of its history that a modern monitoring system might have alleviated. When Director of Engineering Andy Gunn joined the WAMU team, the two set the goal of building the most robust system they could imagine.
Rob contributed his knowledge from managing the prior system and Andy brought his tenacity, creativity, and attention to detail to the project. The result was an implementation of Burk’s Arcturus system of which both engineers are very proud and is a showcase of the system’s capabilities.
[See Radio World’s 2020 Article About This Project]
The monitoring and control project sought to address multiple concerns from the start. Several of the stations have relatively high TPOs in the 20 to 30 kW range, so very solid VSWR monitoring is important. There are unique switching and monitoring considerations to meet some of the backup features incorporated into the antenna systems. There was also a strong desire to ensure the system would accommodate the addition of more stations in the future.
Prior experiences with esoteric failures made redundancy a significant design concern across the system. WAMU wanted dual interlock strings for each station operating in parallel so no single wire would cause an interlock issue for stations. They also added dual dehydrators, which automatically rotate duty cycle via Arcturus, and can be switched online in the event of failure.
Multiple safety features were incorporated: U-links on every transmitter input to the system as well as a key switch and controller lockout system to protect climbers on the tower. There is also a centrally located interlock bypass for when maintenance is required on the VSWR monitoring system itself.
The Burk Plus-X VSWR fit the bill for a self-contained VSWR monitoring unit that would be fast-acting, have three-strike capability, and operate even if it lost connection to the Arcturus controller. Additional Burk Plus-X 600 and Plus-X EM32 units provide the necessary I/O to operate additional functions and monitor critical temperatures, fire, and security statuses throughout the complex.
Burk engineers collaborated with WAMU to program many macros on the Arcturus system that gives it the extensive functionality required. The sheer quantity of monitoring and control points across the system necessitated relatively complex macros, which Burk designed. WAMU also requested the ability to view key system values over the course of a year, so that operating variables across seasons could be tracked. Burk delivered multiple custom pages of monitoring and control in AutoPilot to meet all these needs. Paul Shulins and David Wing of Shulins Solutions provided integration services for the installation of the system. They were vital in thinking through the installation and making sure there were no “gotchas” in this stage.
The Arcturus system has been running reliably for WAMU and its tenants for nearly 18 months. During the initial buildout there were several challenges in ironing out final configurations, but Burk support worked with WAMU as was necessary to get everything as they wanted it to be. The wiring for the system is very complex, and the labeling and documentation for the system is similarly complex. It took a while to determine the best method to label and document the system. The complex macros required extensive testing to ensure they didn’t have any unintended consequences — for instance, opening interlocks in the event of power loss to a single unit or loss of network connection between the devices. Thorough testing and final corrective action ensured the platform will be reliable and responsive to the needs of DC’s largest master FM system for years to come.
Info: Contact Matt Leland at Burk Technology at 1-978-486-0086 or https://www.burk.com.
Radio World User Reports are testimonial articles intended to help readers understand why a colleague chose a particular product to solve a technical situation.
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