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W.Va. Station Puts 128 QAM on Its STL

W.Va. Station Puts 128 QAM on Its STL

An AM station in Morgantown, W.Va., is running twin uncompressed 44.1 kHz audio streams on 950 MHz aural STL in less than 500 kHz of bandwidth using 128 QAM, according to supplier Moseley Broadcasting.
Bowers Broadcasting’s WCLG uses a Moseley SL9003Q system. Dave Chancey of Moseley stated in the company’s announcement that the STL link was well suited for this new feature.
“The short path with quiet RF noise floor allowed us the luxury of going to 128 QAM.”
If bit error performance is not satisfactory, he said, the user will use the Starlink’s standard 32 kHz audio sampling/32 QAM configuration.
Moseley is the first STL manufacturer to use a digital modulation technique known as 128 QAM (128 kb packet or word size Quadrature Amplitude Modulation) to convey twin 44.1 kHz linear stereo audio programs over a conventional 950 MHz STL channel.
Previously the Moseley Starlink SL9003Q-4S system standard configuration provided two uncompressed 32 kHz audio sampled stereo pairs with 32 QAM modulation.
“At Moseley we found this to be very robust and forgiving when used in 950 MHz STL applications where path length, noise and interference are more challenging,” said Chancey. “As the industry converts to HD Radio and a 44.1 kHz audio sampling standard, the 128 QAM modulation technique will allow broadcasters to convey wider audio bandwidth in equivalent RF bandwidth or 32 QAM. We expect that at transmitter sites with RF hostile environs, 128 QAM may have issues with dropouts from interference.”