KAVX-FM, serving the Lufkin/Nacogdoches region of eastern Texas and western Louisiana, has turned on a new Harris HPX20 tube transmitter capable of simultaneous HD Radio and FM transmission. KAVX is a non-profit organization operating under the Lufkin Educational Broadcasting Foundation. The HPX20 is currently transmitting at 9.5kW TPO (FM-only), and operates at an efficient 23kW ERP from a height of 723 feet above ground level.Though transmitting in FM only at this time, the station required a new transmitter with HD Radio-capability to replace an analog-only QEI model. Harris installed a FlexStar HDX-FM digital exciter in the transmitter, providing an easy upgrade path to HD Radio when the station is ready. Tim Swanson, chief engineer for KAVX and sister station KSWP-FM, noted that the current configuration provides plenty of reserve power to transmit both the standard FM signal and an accompanying HD Radio signal when the time comes. The HPX20 has also noticeably improved signal quality throughout the market.“We have had several listeners respond positively about receiving a stronger signal in their area,�? said Swanson. “The staff has noticed the same. Our old QEI model had performed well for nearly 20 years, but a 10kW transmitter pumping out 9.5kW was pushing it.�?Swanson added that the electrical efficiency of the HPX20 was also instrumental in the decision. “Transmitter designs have changed in the last 18 years, and we expect that the HPX will help us lower our costs of operation.�?