The Federal Communications Commission Laboratory has conducted field tests of spectrum devices proposed for unlicensed use in the gaps between television signals, known as white spaces. Broadcasters, led by the National Association of Broadcasters, have been urging a go-slow approach to opening these spaces up, particularly with the uncertainties of the 2/17/09 DTV deadline fast approaching. The FCC itself has confirmed broadcast concerns. The FCC report suggests that "the sample prototype White Space Devices submitted to the Commission for initial evaluation do not consistently sense or detect TV broadcast or wireless microphone signals" and that "the transmitter in the prototype device is capable of causing interference to TV broadcasting and wireless microphones." The clear implication is to hold off on turning this spectrum into the wild wild west for unlicensed devices until it is proven that they can operate without harming incumbent signals. NAB’s Dennis Wharton said, "Yesterday’s FCC testing results confirm what NAB, MSTV and others have long contended: that the portable, unlicensed devices proposed by high-tech firms can’t make the transition from theory to actuality without compromising interference-free television reception."