05.10.2006 08:00 AM
Originally featured on BroadcastEngineering.com
Data Return Link test proves successful
Modulation Sciences (MSI) has successfully tested its new 2GHz Data Return Link (DRL) channels to deliver IFB to field news operations.
DRL was created in the recent “re-farming” or the 2GHz BAS band. The DRL allocation is composed of two 500kHz bands on the upper and lower edges of the new 2GHz Broadcast Auxiliary Service (BAS) band. Each 500kHz DRL band is divided into 20 channels, each 25kHz wide. Those licensed for 2GHz video channels can use the channels after the new BAS band plan has been implemented in their markets.
The FCC granted Modulation Sciences an experimental license to test DRL from its plant in central New Jersey. Because the New York market is still operating on 2GHz under the old band plan, careful coordination was required to avoid interference with ongoing ENG operations.
A directional antenna mounted on the roof of Modulation Science’s building in Somerset, NJ, was used to transmit to small portable receivers. The receivers were belt worn or handheld and were moved around the surrounding area. Coverage was limited by the low height (100ft above mean sea level) of the transmit antenna. However, propagation studies indicate with more typical ENG-support locations where antennas are much higher coverage should exceed that of ENG video operations.
Modulation Sciences is working with several broadcasters in planning operational testing of DRL with transmission from suitably elevated sites.
With a combination of 40 channels per market and directional transmit antennas, DRL offers many new options for Interruptible Fold Back (IFB). After the analog shutdown, DRL will play an essential role in maintaining reliable IFB.
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