Harris, Cox Tout 'Split-Level Combining' for HD Radio

Harris, Cox Tout 'Split-Level Combining' for HD Radio
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Harris, Cox Tout 'Split-Level Combining' for HD Radio

Cox Radio's Steve Fluker, DOE of Orlando's WMMO and Harris engineer George Cabrera have invented what they are calling "Split-level Combining" for HD Radio. Patents are pending on the methodology.
At the Public Radio Engineering Conference in Las Vegas, Fluker said initial tests last Thursday showed the implementation scheme showed promise for saving on a station's operation costs and equipment space needs when they go digital.
In tests conducted April 15, Fluker said he used a Harris HT-5 analog transmitter, and a Harris Z Series-16 for the digital signal. The scheme uses a hybrid IBOC plus FM signal in the auxiliary transmitter. By passing some of the analog signal through the auxiliary IBOC transmitter, combiner losses are reduced and the existing analog transmitter can still be used, he said.
His station TPO is 7.3 kW and the IBOC power level was 73 watts. That compares to traditional high-level combining of 8.5 kW for the analog transmitter and 85 watts for the digital transmitter, with both signals being fed to a high-level combiner.
With the split-level combining, he said, rather than sending 90% of the digital power and 10% of the analog into a dummy load, less power is wasted. He said a station's overall power consumption could be between 5% to 25% less than it would have been with high-level combining using this method.
WFMT's Gordon Carter told the RW Online the method could potentially save his station roughly half a million dollars a year.
Corporation for Public Broadcasting representatives at the show said they would now review recent grant awards totaling more than $5 million to help 76 stations go digital. They want to see if this new implementation, plus the FCC's recent authorization of dual antennas, saves these stations in their conversion costs. If so, grant money could possibly go to more stations than originally announced, CPB said.