Attachment RadHaz Study

This document pretains to SES-LIC-20050825-01183 for License on a Satellite Earth Station filing.

IBFS_SESLIC2005082501183_482331

Globalstar, L.P. Exhibit A Page 1 of 2 Radiation Hazard Analysis INTRODUCTION The following radiation hazard analysis for the proposed antenna is based on the guidelines set forth in OET Bulletin 65, edition 97-01. From Bulletin 65, the maximum permissible exposure (MPE) limit for occupational/controlled exposure MPE has a power density limit of 5 mW/cm2 for the proposed transmit band of 1610 – 1618.725 MHz and when averaged over a 6 minute period. The proposed 1.2 meter antenna will be operated in a controlled area not open to the public. The proposed antenna is located on the Globalstar Gateway site near Clifton, TX. The entire site is enclosed by an 8 foot high chain link security fence with 24 hour per day controlled access. The proposed antenna is located well inside the secure area over 200 feet from the security fence surrounding the site perimeter. NEAR-FIELD The extent of the Fresnel region or near-field, is defined by the equation Rnf = D2  ZKHUH' LVWKHGLDPHWHURIPHWHUVDQG LVWKHWUDQVPLWIUHTXHQF\ZDYHOHQJWKRIPHWHUV Therefore, Rnf = (1.2m)2/(4*0.185m) = 1.95 meters. The maximum power density in the near field is defined by the equation Snf  3 '2), wherH LVWKHDQWHQQDDSHUWXUHHIILFLHQF\RI3LVWKHSRZHUDWWKHDQWHQQDLQSXWIODQJHRI watts, and D is the antenna diameter of 1.2 meters. Snf   P: FP 2) = 0.283 mW/cm2, which is below the maximum allowable exposure level of 5 mW/cm2. FAR-FIELD The distance to the point where the far-field begins is defined by the equation Rff = 0.6*D2  ZKHUH'LVWKHGLDPHWHURIPHWHUVDQG LVWKHWUDQVPLWIUHTXHQF\ZDYHOHQJWKRI meters. Therefore, Rff = 0.6*(1.2m)2/0.185m = 4.67 meters.

Globalstar, L.P. Exhibit A Page 2 of 2 The far-field on axis power density is defined by the equation Sff 3 *  5ff2), where P is the power at the antenna input flange of 2 watts, and G is the antenna transmit gain of 21 dBi, and Rff is the distance to the beginning of the far-field of 4.67 meters. Therefore, Sff = 2000mW*102.1  FP 2) = 0.0918 mW/cm2, which is below the maximum allowable exposure level of 5 mW/cm2. TRANSITION ZONE The maximum power density in the transition zone is defined by the equation St = Snf*Rnf/Rd, where Snf is the maximum near-field power density, Rnf is the near field extent of 1.95 meters. And Rd is the distance to a point in the transition zone. Using a mean distance of 3.31 meters for Rd , St = 0.283mW/cm2*1.95m/3.31m = 0.167 mW/cm2, which is below the maximum allowable exposure level of 5 mW/cm2. ANTENNA SURFACE The maximum power density in front of the antenna reflector (e.g., at the antenna surface) can be approximated by the equation Ssurface = 4P/A, where P is the power at the antenna input flange of ZDWWV$LVWKHPDLQUHIOHFWRUDUHDRU ' 2, and D is the antenna diameter of 1.2 meters. Ssurface   3 '2   P:  FP 2) = 0.705 mW/cm2, which is below the maximum allowable exposure level of 5 mW/cm2. CONCLUSION The preceding analysis follows OET Bulletin 65 and demonstrates that harmful levels of radiation do not exist above the maximum permissible exposure level of 5 mW/cm2 for a controlled access area that may be occupied by operation and maintenance personnel.


Document Created: 2006-02-09 14:45:45
Document Modified: 2006-02-09 14:45:45
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