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 Previous: The Amateur Amateur: A Wealth of Possibilities |  Next: Amateurs Aid as Tornados Devastate Nebraska Communities |
 NTIA Acting Assistant Secretary Michael D. Gallagher. [NTIA Photo] |
NEWINGTON, CT, May 26, 2004--National Telecommunications and Information Administration Acting Administrator Michael Gallagher has hinted at some of the findings in his agency's pending Phase 2 broadband over power line (BPL) study. In remarks May 17 at the United Telecom Council's "Telecom 2004" in Nashville, Tennessee, Gallagher said the complete NTIA Phase 2 BPL study is "targeted for release later this year." While the Phase 2 study will provide "additional guidance" on contending with BPL interference issues, the NTIA has advised against putting the present FCC rule making proceeding on hold until its release.
"Key Phase 2 technical analyses have been completed," Gallagher told the UTC gathering, "and the findings are appended to NTIA's comments on proposed rules." The NTIA has yet to file those comments, although it has posted its Phase 1 BPL study on the proceeding. The comment deadline on the FCC's BPL Notice of Proposed Rule Making (NPRM) in ET Docket 04-37 was May 3, but the period for reply comments ends June 1.
Responsible for developing telecommunications policy for a White House that's promoting BPL, as well as for administering federal government radio spectrum that could be affected by the technology, the NTIA finds itself with a stake on both sides of the BPL controversy.
Gallagher's Telecom 2004 presentation acknowledged that the principal concern surrounding the technology is that "BPL systems might interfere with federal government radio communications or other state and private radio operators." The NTIA's Phase 1 study showed that interference risks already are high under existing Part 15 rules, and it advises retaining--not relaxing--existing Part 15 power limits. Among the Phase 1 study's recommendations for reducing interference are frequency shifting and notching as well as "refined compliance measurement procedures," which Gallagher characterized as solutions "to satisfy all parties." BPL proponents have said they can comply with Part 15 emission limits, but NTIA says they're basing that assertion on the use of existing measurement procedures.
The agency has said its Phase 2 study will, among other things, assess interference risks due to aggregation (ie, total emissions from multiple BPL systems) and ionospheric propagation of interfering signals from BPL systems. Gallagher said the Phase 2 study has determined that BPL aggregation and ionospheric propagation "is not a potential near-term problem."
The NTIA predicts that millions of BPL devices can be deployed under the rules the FCC is expected to adopt--probably later this year--before ionospheric propagation and aggregate BPL emissions become an interference issue.
ARRL CEO David Sumner, K1ZZ, says he's curious to hear the NTIA rationalize its "near-term" assertion. "Does this mean it's okay to go ahead with a bad idea if the problems it causes are sufficiently far in the future?" he asked.
The Phase 2 study also will evaluate the effectiveness of proposed Part 15 measurement techniques and recommend a "height-correction factor" of 5 dB to BPL measurements made at a height of 1 meter, Gallagher said. It also will advise requiring a peak field strength measurement search "all along the power line" at a distance of 10 meters and at a height of 1 meter.
The NTIA acknowledges that peak field strength is as much as 20 dB higher--a factor of 100--than the peak measured at a height of 1 meter under current Part 15 rules. Because the peak does not occur consistently at a particular distance from a BPL device along the power line, the NTIA says, technicians must seek a peak field strength by tracking the entire power line. According to the NTIA, this will cover 80 percent of peaks at any height.
The
agency has determined that a moderate-to-high probability of interference
exists to a fixed station from BPL power lines at a distance of 450
meters--approximately 1480 feet--and to a mobile station at a distance of 55
meters--approximately 180 feet.
 A BPL extractor for a field test system in Cedar Rapids, Iowa. [Alan Erickson, WB0OAV, Photo] |
To "fulfill special protection requirements," Gallagher said, the NTIA will suggest "minimal" coordination areas--where a specified authority would coordinate all planned BPL deployment--plus excluded bands and exclusion zones. The NTIA recommends "voluntary coordination" with respect to other radio operations plus "mandatory Access BPL power control, frequency agility and shut-off capabilities" to reduce interference risks and to expedite interference mitigation.
The NTIA further proposes that BPL rules provide for "prompt response to complaints of suspected interference" and recasting the FCC's Part 15 shutdown requirement as "a last resort."
"Our BPL study of more than 10 million signal samples shows that solutions exist to all identified BPL technical issues," Gallagher concluded.
That's true, Sumner said, "but only if you include shutting a BPL system off and keeping it off as a 'solution.'"
During a White House meeting May 20, ARRL officials asked the Bush administration to heed its own experts at the NTIA and back away from its support of BPL in favor of less troublesome broadband technologies. In its comments in the proceeding, the League also called on the FCC to put its BPL proceeding on hold to allow more thorough research of its interference potential to licensed radio services.
For additional information, visit the "Broadband Over Power Line (BPL) and Amateur Radio" page on the
ARRL Web site. To support the League's efforts in this area, visit the ARRL's
secure BPL Web
site.
| Previous: The Amateur Amateur: A Wealth of Possibilities | Next: Amateurs Aid as Tornados Devastate Nebraska Communities |
