Ultra-wideband (UWB) developer XtremeSpectrum has submitted propo...

Ultra-wideband (UWB) developer XtremeSpectrum has submitted proposal to FCC that would “seriously limit” UWB emissions below 3.1 GHz, said attorney Mitchell Lazarus. He responded to letter written to NTIA from Asst. Defense Secy. for Command, Control Communications & Intelligence John Stenbit spelling out DoD’s position on UWB (CD Jan 25 p1). Stenbit told Commerce Dept.’s Deputy Asst. Secy. for Communications & Information Michael Gallagher that DoD required that there be no intentional emissions below 4.2 GHz except for imaging systems. DoD proposal to NTIA also includes out-of-band emissions that would meet “stringent standards” previously provided by DoD to NTIA staffers. XtremeSpectrum had told FCC in Sept. that it didn’t object to emissions limits in GPS band supported by GPS Industry Council. These include limits that are 35 dB below certain levels of Part 15 and additional 10 dB suppression of spectral lines as measured with 10 kHz resolution bandwidth. While there are several systems on record at FCC that indicate need for protection below 3.1 GHz, there is “almost nothing in the record showing a need between 3.1 and 4.2 GHz,” Lazarus said. “XtremeSpectrum has offered a 10 dB cut in that band anyway to expedite getting the rules out, although we don’t think it’s necessary. We don’t see any reason to limit emissions below 4.2 GHz any more steeply than by 10 dB.” On concerns over aggregation of UWB signals, Lazarus said company submitted figures to FCC last week that calculated potential aggregation impact of UWB signals. “If you have an ultra-wideband emitter 3 meters away and 100 meters away there are 100,000 ultra-wideband emitters, all at the same power,” Lazarus said the 100,000 UWB emitters will only contribute “1 percent as much interference as the single unit 3 meters away.”