From our Who’s Buying What page: Six months into their U.S. partnership, Dielectric and SCMS have installed a new DCR-M ring-style antenna system for Minnesota Public Radio, improving broadcast capabilities for KNBJ(FM) and KCRB(FM).
The project involved designing and delivering a 12-bay antenna and a combiner to replace an outdated system.
According to a joint press release, the Dielectric antennas were built with a shorter-than-standard lead time as the existing antenna, in service for more than 30 years, showed signs that end of life was fast approaching.
Vincent Fuhs, manager of the Network Engineering Group for Minnesota Public Radio, said Northern Minnesota is among the harshest outdoor environments in the U.S., and “the effects of many long winters had finally caught up” with the old antenna.
“That included large cracks and moisture infiltration from icing damage, raising VSWR levels to the point where reflected power became a concern,” said Fuhs in the release. “The transition to a modernized antenna system eliminates RF concerns like these that emerge over time, while also opening new possibilities such as raising our HD Radio insertion levels from -20 to -14dBc.
“The DCR-M design offers the amount of bandwidth we need to maintain the improved HD Radio power that comes with that 6dB sideband increase, which makes HD Radio programming more accessible through the market.”
Minnesota Public Radio transitioned to its new Dielectric antenna system in July, “with immediate improvements to RF efficiency and performance,” according to the release. Improvements included corrections to an escalating reflected power issue that affected transmitter performance, and the stability to maintain higher sideband levels that better support HD Radio signals.
“Dielectric also produced the ring-style system with the tower’s weight restrictions in mind, opting for a dual center-fed design to maximize bandwidth and reduce the effects that ice buildup creates — a critical requirement as the addition of radomes would exceed the weight threshold,” the companies said.
Additionally, Dielectric built a combining system to keep signals from mixing as they exit the transmitter and begin their journey up the tower.
“The patented Manifold design includes two distinct space-saving sections, each taking in one station’s on-frequency signal and merging them for carriage through the transmission line and the DCR-M system,” read the press release. “On arrival, the 12-bay DCR-M system, positioned at just over 1,000 feet in altitude, combines the two frequencies radiating the KNBJ’s 65kW and KCRB’s 83kW ERP signals.”
SCMS Regional Sales Representative Andy Cole, who has a 20-year business relationship with Fuhs, was responsible for bringing Dielectric into the project.
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