NAB Requests FCC Review IBOC Dual Antenna Concept

NAB Requests FCC Review IBOC Dual Antenna Concept
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NAB has been busy at the FCC. The association submitted a report to the FCC on the results of experiments with FM stations using IBOC and dual antennas. An ad hoc antenna group organized by NAB believes the so-called "dual antenna" approach has an advantage over high level and low-level combining, which uses a single antenna to broadcast the combined analog/digital signals.
"The use of separate antennas (to broadcast the analog and digital signals) results in smaller transmitters, lower cost of equipment acquisition and operation, and reduced floor space requirements in the transmitter room," states the NAB in its report.
In its interim authorization for IBOC, the commission did not allow stations to use separate antennas. The NAB ad hoc technical group believes the concept will help stations get on the air more quickly with HD Radio.
NAB has asked the FCC to allow stations broadcasting with HD Radio to use separate antennas if they meet certain criteria: The digital transmission must use a licensed auxiliary antenna; The auxiliary antenna must be located within three seconds of latitude and longitude of the main antenna; and The vertical separation of the antennas must be limited such that the auxiliary antenna is between 70 and 100% of the HAAT of the main analog antenna.
The group tested the concept at FM stations WMGC, Detroit; WDHA, Dover, N.J. and KDFC, San Francisco.
An NAB spokesman said the group was hopeful the NAB would approve the concept. To see the report, go to:


AM IBOC, Dual Antennas De-Mystified

Radio World asked several of our contributors to attend various sessions at the NAB2003 convention. Here, Michael LeClair summarizes presentations at "IBOC DAB - Ready For Prime Time" of the Broadcast Engineering Conference.