“White Spaces” – The Database

During the last few days, the FCC released the names of those that will maintain the database for the “White Spaces” equipment. Among them are the major proponents of the new wireless service and each of the databases will be synchronized. The database will be used to determine what channels are available to the equipment.

My opinion is, that there is no such thing as “White Spaces”. Actually, I just don’t like the terminology.

In simple terms the so called White Spaces, are guard bands, placed on alternate TV Channels, on a per market basis, to provide a suitable C/I that will intern, accommodate the integrity of the RF signal. For reference, with analog TV we were looking for numbers in excess of 40 dB, for digital equipment utilizing 8VSB modulation, we now look for C/I’s of better than 28 dB, or so. Many of the proponents had wanted to use the unassigned channels (guard bands) between each channel.

Thankfully the FCC, understood the need to protect the guard bands. As it turns out, in many locations and markets there is spectrum where both channels and their respective guard bands are not used, these will accommodate the new “unlicensed Television Band Devices”. Officially, “TVBDs” and the Rules and Regulations are contained in CFR 47, Parts 15.701-15.717.

I did a quick review of the likelihood of deployments in my own home area, when the Order was first released, and find that it is unlikely that a deployment nearby could take place. Based on both assigned and adjacent channel requirements under the new regulations, I believe that this area is without “White Spaces”. (Channel 48 will be close.) Certainly, this is not the only location that may be problematic. (Southeastern PA.) For you non-TV tech types, a TV channel is six MHz wide.

I’m not sure at this point if the equipment will be sold primarily to Wireless ISP’s or to retail customers. I wonder how this will impact the distribution channels (marketing not frequency) for hardware? How many installers or purchasers of the equipment will find that the wireless devices won’t work simply because the database denies, and rightfully so, the activation of the equipment?

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