Sec.  27.1184   Triggering a reimbursement obligation.

   (a) The clearinghouse will apply the following test to determine when an AWS
   entity has triggered a cost-sharing obligation and therefore must pay an AWS
   relocator of a BRS system in accordance with the formula detailed in
    Sec. 27.1180:

   (1) All or part of the relocated BRS system was initially co-channel with
   the licensed AWS band(s) of the AWS entity;

   (2) An AWS relocator has paid the relocation costs of the BRS incumbent; and

   (3) The other AWS entity has turned on or is preparing to turn on a fixed
   base station at commercial power and the incumbent BRS system would have
   been within the line of sight of the AWS entity's fixed base station,
   defined as follows.

   (i) For a BRS system using the 2150–2160/62 MHz band exclusively to provide
   one-way transmissions to subscribers, the clearinghouse will determine
   whether there is an unobstructed signal path (line of sight) to the
   incumbent licensee's geographic service area (GSA), based on the following
   criteria: use of 9.1 meters (30 feet) for the receiving antenna height, use
   of the actual transmitting antenna height and terrain elevation, and
   assumption of 4/3 Earth radius propagation conditions. Terrain elevation
   data must be obtained from the U.S. Geological Survey (USGS) 3-second
   database. All coordinates used in carrying out the required analysis shall
   be based upon use of NAD–83.

   (ii) For all other BRS systems using the 2150–2160/62 MHz band, the
   clearinghouse will determine whether there is an unobstructed signal path
   (line of sight) to the incumbent licensee's receive station hub using the
   method prescribed in “Methods for Predicting Interference from Response
   Station Transmitters and to Response Station Hubs and for Supplying Data on
   Response Station Systems. MM Docket 97–217,” in Amendment of 47 CFR parts 1,
   21 and 74 to Enable Multipoint Distribution Service and Instructional
   Television Fixed Service Licensees to Engage in Fixed Two-Way Transmissions,
   MM Docket No. 97–217, Report and Order on Further Reconsideration and
   Further Notice of Proposed Rulemaking, 15 FCC Rcd 14566 at 14610, Appendix
   D.

   (b) If the application of the trigger test described in paragraphs (a)(3)(i)
   and (ii) of this section, indicates that a reimbursement obligation exists,
   the clearinghouse will calculate the reimbursement amount in accordance with
   the cost-sharing formula and notify the subsequent AWS entity of the total
   amount of its reimbursement obligation.

   (c) Once a reimbursement obligation is triggered, the AWS entity may not
   avoid paying its cost-sharing obligation by deconstructing or modifying its
   facilities.