Radiation Hazard Tecom Qest

0236-EX-PL-2009 Text Documents

Row 44, Inc.

2009-06-19ELS_99151

Exhibit 3 Radiation Hazard Analysis Tecom/Qest Antenna This exhibit presents the radiation hazard analysis for Row 44 using the FCC procedure outlined in FCC Bulletin #65. The limit for exposure to RF energy, for frequencies greater than 1.5 GHz, is 5 mW/cm2 for up to a 6 minute duration (occupational/controlled exposure) and 1 mW/cm2 for up to a 30 minute duration (general population/uncontrolled exposure).1 Analysis for exposure to radiation is presented for the near field, far field and the transition region. Safe limits are computed for the controlled and uncontrolled exposure for both the antenna main beam and sidelobes. The near field region for the main beam is defined in terms of the radius Rnf according to the relation Rnf = D2/4λ where D is the antenna panel width and λ is the transmit wavelength. The near field maximum power density, Snf, is determined from Snf = PPA/A where PPA is the transmit power (after cable losses are accounted for) and A is the surface area of the antenna panel. With an antenna height h, the surface area A=Dh The far field region for the main beam is defined in terms of the radius Rff given by Rff = 0.60 D2/λ The far field power density Sff at the minimum far field radius is given in terms of the EIRP denoted by PEIRP according to Sff = PEIRP/4π Rff2 When the radius is expressed in meters, the power densities are w/m2. The results are converted to mW/cm2 by multiplying the power densities in w/m2 by 0.1. Near Field Exposure from Main Antenna Beam 1 “Questions and Answers about Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields,” Federal Communications Commission, Office of Engineering and Technology, Bulletin 65, Fourth Edition, August, 1999, p.15. http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet56/oet56e4.pdf 1

The Tecom/Qest antenna has dimensions D=0.625 m (24.6”) and h=0.157 m (6.2”) and a surface area A=0.098m2. At the highest transmit frequency of 14.5 GHz, the wavelength is 0.0207 m. The near field radius is then Rnf = 4.72 m Since the maximum transmit power is PPA=10 watts, the maximum power density in the near field is Snf = 10.2 mW/cm2 Far Field Exposure from Main Antenna Beam Based on the wavelength and panel width given above, the far field radius is then Rff = 11.3 m The maximum EIRP is 38.8 dBW resulting in a far field power density of Sff = 0.47 mW/cm2 Transition Region Exposure from Main Antenna Beam Assuming that the field density decrease linearly from Snf = 10.2 mW/cm2 to Sff = 0.47 mW/cm2, then the 5 mW/cm2 power density for controlled exposure occurs at a distance of 8.25 meters For the case of the 1 mW/cm2 power density for uncontrolled exposure the safe distance is 11 meters. Based on antenna sidelobes with 12 dB reduction from the main beam and using the far field expressions, no individual in a controlled exposure should be within 0.9 meters ( ~3 feet) of the antenna while it is transmitting and for no longer than 6 minutes. The 30 minute exposure range for an uncontrolled exposure due to sidelobes is 2 meters ( ~6.6 feet). Summary This document presents the radiation hazard analysis for Row 44’s system incorporating the Tecom/Qest antenna and the maximum EIRP of 38.8 dBW. Individuals in a controlled exposure should be at least 8.25 meters (27 feet) away from the antenna and for no more than 6 minutes and in an uncontrolled exposure should be at least 11 meters (36 feet) away for 30 minutes, if they are in the main beam of the antenna. 2


Document Created: 2009-06-19 13:52:35
Document Modified: 2009-06-19 13:52:35
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