Comments have been invited on an NAB/SBE proposal aimed at (slightly) improving the audio quality on the TIS without interfering with AM stations.
Last July we blogged about changes the Commission had adopted to improve Travelers' Information Stations (TIS). At that time, the FCC proposed another fairly drastic change – the elimination of certain filtering requirements – that might potentially improve the service. The proposal went farther than some commenters thought advisable, which prompted them to propose a more moderate approach and, in response, the Public Safety and Homeland Security Bureau has now issued a Public Notice seeking further comment. (The Bureau probably could have skipped this step, but this writer thinks it’s a good thing they didn’t.)
TIS are low-power AM stations broadcasting information of interest to motorists, including traffic and road conditions, travel advisories, hazards, directions and the like. Each station covers only a small geographic area, most commonly along major highways and near tourist destinations.
AM service is notoriously interference-prone, with TIS as a potential source. The interference occurs because of the “sideband” portion of the TIS-transmitted AM signal. Excessively wide sidebands can cross over into another station’s channel, causing interference to that station. With AM stations – whose signals, particularly at night, can extend for hundreds of miles – this can cause big problems.Continue Reading...