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Acrodyne Services’ ‘Transmitter on Wheels’ Keeps Broadcasters On-Air During Retooling

Acrodyne Services MAT
(Image credit: Acrodyne Services)

BALTIMORE—Acrodyne Services has deployed a self-contained TV transmission solution designed to keep broadcasters on air while they replace or modify their existing transmitters.

The Mobile Acrodyne Transmitter (MAT), offering support for both ATSC 1.0 and 3.0 transmission, is a climate-controlled trailer with a one-rack, liquid-cooled Rohde & Schwarz THU9evo UHF 19kW transmitter with 12 amplifiers, a Dielectric tunable mask filter, patch-panel, test load plus pumps and separate heat exchangers for the transmitter and test load.

The UHF version of MAT has been deployed several times, and a VHF version is planned for deployment later in the year, Acrodyne Services said.

“Stations and TV groups are continuing to upgrade their broadcast infrastructures by replacing old transmitters,” said Acrodyne Services General Manager Andy Whiteside.

“There are low-power solutions and other workarounds, but none of them are ideal, especially for stations that have limited space or run into unexpected delays because of logistic and structural issues. MAT provides a clean, external and high-power solution that allows broadcasters to conduct business as usual,” he said.

Stations that rely on MAT need only supply AC power and an input signal from master control. Acrodyne provides a run of coaxial flex line to connect MAT’s output to the antenna to maintain regular broadcasting, Acrodyne Services said. 

MAT’s initial deployment was in June 2020 at WLFL/WRDC, the Sinclair Broadcast Group duopoly serving Raleigh-Durham, N.C.  At the time, Sinclair was replacing the stations’ transmitters—both in the same room—and installing a new filter for WRDC. (Acrodyne Services is a wholly owned subsidiary of Sinclair.)

“There just wasn’t enough room for all of that work,” said Rusty Mooney, Sinclair manager of TV transmission engineering. “You’d run out of wall space trying to keep one transmitter running while trying to build a new transmitter.”

Acrodyne Services MAT

(Image credit: Acrodyne Services)

With MAT parked outside the facility and transmitting, the old WRDC transmitter was removed. When the new WRDC transmitter was commissioned, MAT was quickly reconfigured to broadcast for WLFL while its transmitter was replaced.

MAT also was used January through March at Sinclair’s KDNL in St. Louis while the station completed extensive renovations and replaced its two-cabinet IOT transmitter, Acrodyne Services said.

The idea for a transmitter on wheels stems from the FCC repack of TV spectrum. In September 2020, WHKY, the Long Communications-owned independent station serving Charlotte, N.C., rented an early version of the mobile transmitter while updating its facility and installing a new transmitter, Acrodyne Services said. 

Once Sinclair has completed all of its repack projects, the broadcaster expects to replace its remaining IOT transmitters at about 20 of its stations with solid-state transmitters.

Dale Scherbring, Sinclair director of engineering for RF transmission, expects to use MAT at those locations and at the VHF-to-UHF conversions currently being considered. However, he said MAT can also be deployed for emergency or disaster situations, and the system can be operational within a day.

MAT will be available to all broadcasters subject to demand and availability, Acrodyne Services said. 

More information is available by emailing Acrodyne Services.

Phil Kurz

Phil Kurz is contributing editor to TV Technology