John Shutt wrote: >> First, how is this deteremined? Is it manually configured >> (unlikely) or is it dynamically determined by the device, >> as IEEE 802.11 access points do? In the latter case, I >> think my scenario could easily unfold. > > Bert, > > Try Title 47, United States Code of Federal Regulations, > Part 15: > > http://www.access.gpo.gov/nara/cfr/waisidx_04/47cfr15_04.html Thanks, John. The pertinent section is 15.242. This applies to the US high VHF and UHF TV bands. Assuming that the allowable equipment in this band would no longer be limited to the medical facilities mentioned here, but instead will possibly be consumer equipment, I don't see how these rules can continue to apply as written. Because you can't expect the consumer to measure distances from the Grade B contour of multiple TV towers, and the reseller doesn't know where a given consumer will locate the equipment. Furthermore, this catch-all paragraph at the end is also unlikely to be of any use for consumer-configured equipment: "The manufacturers, installers, and users of biomedical telemetry devices are reminded that they must ensure that biomedical telemetry transmitters operating under the provisions of this section avoid operating in close proximity to authorized services using this spectrum. Sufficient separation distance, necessary to avoid causing or receiving harmful interference, must be maintained from co-channel operations. These parties are reminded that the frequencies of the authorized services are subject to change, especially during the implementation of the digital television services. The operating frequencies of the part 15 devices may need to be changed, as necessary and in accordance with the permissive change requirements of this chapter, to accommodate changes in the operating frequencies of the authorized services." As a result of this, what I think is likely is that consumer equipment operating in these white spaces will be auto-configured, like Wi-Fi access points. And that's where I think you're likely to see problems. The equipment may think it is "5.5 Km distant from the Grade B contour" of a UHF station, only because that's what it's signal strength meter indicates, where the consumer has the equipment located. In fact, this may interfere with an OTA station that Joe next door was watching happily in the past. But if this new equipment is instead professional grade stuff, like fixed WiMax base stations, then perhaps that's a different matter. Then the people affected would more likely be limited to TV production folk, as Ken described earlier. Bert ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.