Doug Lung /
Don't Depend on Cell Phones for Critical Station Communications
If you followed the news reports on the impact of the magnitude 5.9 earthquake on cities in the northeast U.S., you probably noticed the reporters said cell phone networks were jammed after the quake hit. While I haven't heard of stations having problems communicating with news crews
, as happened during the tornadoes in the south central part of the U.S. earlier this year, it does emphasize the need for stations to maintain alternate methods of communicating with news crews, usually IFB and program coordination on frequencies in the 161 MHz and 450/455 MHz broadcast auxiliary service (BAS) bands.
Broadcasters may have problems obtaining support and replacement radios for these legacy analog FM radio systems as FCC Narrowbanding deadlines approach
. Part 74 radios are not subject to the narrowbanding deadline because these frequencies are used for relaying programming from remote sites to the studio and to carry continuous feeds of program audio interrupted by cues from the studio to talent in the field (IFB)
Before analog TV was shutdown, many stations used Modulation Science's pro-channel equipment to deliver program audio and cues on an audio subcarrier over-the-air. In preparation for the DTV transition, Eric Small and Modulation Sciences developed a low-delay digital audio system, the Digital PROceiver
to carry an IFB audio stream on a station's digital signal. In June Modulation Sciences announced it was ending U.S. sales
. Apparently the company reconsidered this as many TV station engineers, at least those in the NE, received an email from Modulation Sciences pointing out the risk of depending on IFB over cell phone and the advantages of their PROceiver product.
It is interesting to note that in Washington D.C. and other major cities affected by the earthquake saw no reported damage to the cellular infrastructure. The loss of cell service was due to a large number of people trying to reach friends and family at the same time. This shows that it doesn't require tornadoes or a hurricane knocking down towers to cause problems with cell phone service!