Texas station may be first to transmit two HD, one SD stream in single channel

KXII TV, the Gray Television-owned station in Sherman, TX, has launched what may be the world's first live ATSC service with two HD channels and one SD channel in the allocated 19.4Mb/s spectrum.

The station is simultaneously broadcasting CBS in 1080i HD, Fox in 720p HD and MyNetwork, branded "MyTexoma," in 480i SD. The station is using Harmonic DiviCom MV 500 MPEG-2 HD encoders and MV 100 MPEG-2 SD encoders for its digital upgrade to deliver the three channels in its 6MHz spectrum allotment. Statistical multiplexing is being done with Harmonic’s DiviTrack, and the whole system is being managed by its NMX Digital Service Manager.

According to station chief engineer Randy Wells, the station devotes “a rather generous amount” of bandwidth to the HD streams — 5Mb/s to 15Mb/s for the CBS stream and 4Mb/s to 14Mb/s for the Fox stream — and is “pretty lean” on the SD stream, which runs between 1Mb/s and 6Mb/s.

To learn more about KXII’s implementation read: "KXII transmits two HD, one SD channel in 6MHz," a recent Sound Off interview in HD Technology Update.

For more information, visit www.harmonicinc.com.