Cover Letter

4717-EX-RR-1995 Text Documents

COLORADO STATE UNIVERSITY

1999-07-19ELS_10819

                                                               poc. 29467/1—4.16
                                      ff»;fi!%%          Ref. Doc. 28993/1—4.16
FOR                                                     UNITED STATES DEPARTMENT OF COMMERCE
                                                        National Telecommunications and
                                                    f   Information Administration
                                        "Yares of       Annapolis Office
                                                        179 Admiral Coch    Ori              n
                                                        Annaporl?:?wd? "‘Pi401 __   éflf[ 6~/+7
                                                        September 22, 1995




      William D. Gamble
      Deputy Associate Administrator, NTIA
      U.S. Department of Commerce
      Washington, D.C. 20230

      Dear Mr. Gambile,

             As you are aware, the working group on 404 MHz wind profilers chaired by
      Gary Patrick/NTIA recommended an extension of operating authority for the period
      of April 1, 1995 to September 30, 1995. During this period, a number of
      constraints continued to be imposed on 404 MHz profilers to protect the safety—of—
      life Cospas—Sarsat satellite system. These constraints included: 1) low mode
      output power was reduced on Wind Profiler Demonstration Network (WPDN)
      profilers to a maximum of 4 kW, 2) emissions from each WPDN profiler are
      inhibited whenever a Cospas—Sarsat satellite passes within 41 degrees of the zenith
      above that profiler, and 3) emissions from each non—WPDN profiler are inhibited
      whenever a Cospas—Sarsat satellite passes within 85 degrees of the zenith above
      that profiler.      '

            During this period and operating under the constraints described above, there —
      has been only one WPDN profiler detected by Sarsat. This occurrence, the first
      since February 25, 1995, was on one satellite pass on August 7, 1995. NOAA, as
      the agency responsible for both Sarsat and majority of 404 MHz profilers, has
      investigated and corrected the problem, caused by a combmatlon of
      communications failure and human error.

             In addition, during this period further tests have been made that could assist
      in changing the existing operational wind profiler constraints (i.e., power, inhibit
      elevation angle}). These include closed—system tests on the Sarsat Search and
      Rescue Processor(SARP) instrument to determine the impact from 404 MHz wind
      profiler emissions and measurements of the WPDN antenna pattern at 406.05
      MHz.

            At this time, system analyses using the results of these tests have not been
      completed. As a result, we recommend that existing assignments for 404 MHz
      wind profilers be extended until September 30, 1996, using the same constraints
      as defined in the previous extension. The United States Mission Control Center
      (USMCC) will continue monitoring interference to Sarsat during this period. We
      anticipate that a further extension will be requested at that time. Furthermore,


modifications to existing wind profiler constraints during this one year period would
require coordination and appropriate testing using selected wind profiler(s) and
satellite passes. This procedure would allow proper validation of any suggested
changes to current profiler operations, thus mlmmlzmg long—term impact to the
Cospas—Sarsat system.




                                             Sincerely,




 |         /g                             /                                             —
Gary Pafnck               Arthur Radice \-                Wayne Wamback
Chairman                  Army Representative              AF Representative




                                    [(                    a) WLDg.           me
Ronald Grandmaison         ichard Barth                      chael Grunden
CG Representative       — DoC Representative              Navy Representative



Document Created: 2001-08-21 04:50:27
Document Modified: 2001-08-21 04:50:27

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