Wireless devices operating in unused portions of television spectrum received a boost Sept. 23 when the FCC issued its Second Memorandum Opinion and Order aimed at resolving numerous legal and technical issues.
The Second MO&O takes “steps to ensure that incumbent services are protected from interference from the use of white spaces in various ways,” according to a commission press release issued announcing its actions. Protection of those incumbents, which include TV broadcasters and wireless mic users, is laid out in detail.
With the Second MO&O, the commission affirmed its decisions related to protecting full power TV stations, Class A TV stations, LPTV stations, TV translators and TV booster stations from harmful interference emanating from new TV band devices based on their protected TV signal contours. In the newly released document, the FCC stood by an earlier decision to base allowable TV band device (TVBD) operation on the protected contours of DTV stations defined in accordance with the F (50,90) curves specified in commission rules and analog TV contours defined in accordance with the F (50,50) curves specified in commission rules.
Previously, the commission required fixed TVBDs and Mode II personal/portable TVBDs operating with 40mw or greater of power to remain outside the protected contours for co-channel and adjacent channel TV stations. Those TVBDs operating at lower power are permitted in the contours.
The commission also affirmed its decision to give LPTV stations the same signal contour protection as full power TV stations. “Low power stations may provide the only over-the-air broadcast services in rural areas, and we disagree that viewers of those stations should receive less protection than viewers of full service stations,” the commission said in the MO&O.
The commission also chose not to establish any new requirement covering the use of TVBDs in close proximity to amplified indoor antennas. In doing so, the commission reasoned that the use of a TVBD close to an amplified antenna would be “under the control of the same party who could take steps to eliminate interference.” A previous order requires manufacturers to include information on ways to resolve such interference issue; therefore, the commission saw it unnecessary to add new requirements, the Second MO&O said.