Craig wrote: > This is not spectrum set aside for TV use. It is spectrum set aside to protect high powered broadcasters who are using the same frequency in an adjacent market. This is the main reason that the current broadcast TV system is SO INEFFICIENT with respect to spectral re-use.< Craig, This is an academic argument that you circulate with regularity. Surely you aren't seriously suggesting that we scrap the billions of dollars invested in the current DTV transmission system. Would the potential recipients of this freed up spectrum be willing to fund the enormous amount of construction required to implement such a change? Also, you should learn more about the FCC allocation process. Many UHF channels can not be utilized within a market simply because they are "Taboos" that can create harmful IM interference to other stations within that market. One simply can not use "intuitive" arguments regarding channel assignments; there are physical axioms which must be taken into account. Consider this: "In my most recent experimental studies, I found that Triplets of Undesired DTV signals which are asymmetrical, such as channels 30, 32 & 37 produce a broad spectrum of noise from channel 22 to 45 inclusive. (This will be published in a "TV TECHNOLOGY" February issue). The point here is that such signals could be either DTV or from unlicensed devices or a mix. They all look and act the same. This kind of super-broadband interference may jam multiple DTV signals.....". Here Charlie Rhodes reports on yet another possible source of the seemingly inexplicable failure of ATSC reception in many locations. Such interference should be reduce with the NTSC shutdown but will then increase if unlicensed devices are authorized in these so called White Spaces.