‘The Light’ Goes With Rohde & Schwarz For Transmitter Upgrade


A Contemporary Christian AC noncomm serving the Asheville, N.C., market has upgraded its transmitter and, at the same time, cut its energy costs by going with Germany’s Rohde & Schwarz.

Class C3 100kw WMIT-FM, licensed to Black Mountain, N.C., is now using an enhanced R&S THR9 FM transmitter.

This cut owner Blue Ridge Broadcasting Corp.‘s energy costs by 15-20 percent with its recent upgrade to an R&S THR9 FM transmitter.

The station’s transmitter and antennas are sited on top of 6,600-foot Clingman’s Peak, giving WMIT city-grade coverage in the Greenville-Spartanburg, S.C., market and the Johnson City-Bristol-Kingsport, Tenn.-Va., market. It can also be heard in much of the Knoxville area, and in the Gastonia, N.C. area to the west of Charlotte.

With WMIT’s aging transmitter needing to be replaced, WMIT Chief Engineer Joshua Pierce sought to reduce operating costs and space requirements without sacrificing broadcast quality.

He also needed a transmitter with a product life expectancy of at least 15-20 years.

With the R&S THR9, WMIT moved away from air-cooled, vacuum tube technology to a liquid-cooled, solid-state design. The station control room’s air conditioning requirements fell from 15 tons to 4 tons, as a result.

The self-contained 20kW unit fits in a single standard rack and accepts native input of 3-phase 208V. The pump for the liquid coolant system is housed inside the transmitter cabinet, which is under seven feet high.

Normal operation is virtually silent because all subsystems, including the power supplies in the amplifiers and the power combiner, are liquid-cooled.

“When walking in the room, the only noise comes from the auxiliary equipment, and the transmitter delivers 76 percent efficiency right out of the box,” Pierce said. “I’m impressed by the fact that the pumps and cooling fans are not set and self-run, but adjust speed automatically to the temperature you set.”

As far as performance, Pierce said the R&S TCE900 exciter provides top audio quality without colorization. “What comes in goes out, without adding or subtracting any artifacts,” he explained. “The audio is transparent and remains true to the original.”