MPE CALCULATION

FCC ID: K6630303X3S

RF Exposure Info

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FCCID_846098

FCC RF Exposure Requirements General information: FCC ID: K6630303X3S Device category: Mobile per Part 2.1091 Environment: Uncontrolled Exposure Mobile devices that operate under Part 80 of this chapter are subject to routine environmental evaluation for RF exposure prior to equipment authorization or use if they operate at frequencies of 1.5 GHz or below and their effective radiated power (ERP) is 1.5 watts or more. However, compliance with the power density limits of 1.1310 is not required. Antenna: The manufacturer does specify an antenna with a gain of 3 dBi to be used with this device. This device has provisions for operation in a vehicle (marine vessel), or a fixed location. Configuration Antenna p/n Type Max. Gain (dBi) Boat Any omni 3 Operating configuration and exposure conditions: The conducted output power is 25 Watts. Typical use qualifies for a maximum duty cycle factor of 50%. - Part 2.1091 states that devices are excluded from routine evaluation if the EIRP is less than 2.46Watt (or 1.5WERP). - Vehicle Operation: The maximum antenna gain that can be used is 3dBi. A coaxial cable of the type RG 58 has a loss of 1dB for a length of 15 feet. MPE Calculation: The minimum separation distance is calculated as follows: The limit for uncontrolled exposure environment below 300 MHz is 0.2 mW/cm2 . 9/17/2007 Page 1 of 3 FCC ID: K6630303X3S

Channel frequency: 156.025-157.425 MHz The conducted power output is 25 watt. The coax loss was taken as 1 dB. Antenna gain was taken as 3 dBi 50% talk time in 30 minutes Power in Watts Duty Factor in decimal % (1=100%) W := 25 D := 1 for an FM device D=1 Exposure time in minutes U := 30 (use 6 for controlled and 30 for uncontrolled) E := 15 E PC := percent on time Wexp := W ⋅ D⋅ ⎛⎜ ⎟ E⎞ U ⎝ U⎠ PC = 0.5 Time compensated power output Wexp = 12.5 Watts W1exp := Wexp⋅ 1000 4 W1exp = 1.25 × 10 mWatts ___________________________________________________________________________ Antenna gain Coax Loss For all VHF frequencies dBd := 0.85 CL := 1 dB S is fixed at 0.2 mw/cm^2 G := dBd + 2.15 − CL f := 300 G= 2 Net gain in dBi f S := G 1500 10 Gn := 10 mW S = 0.2 from Gn = 1.585 Gain Numeric 2 OET 65 cm ( W1exp⋅ Gn) R := (4⋅ π⋅ S) R Rinches := 2.54 R = 88.784 distance in centimeters required for compliance Rinches = 34.954 9/17/2007 Page 2 of 3 FCC ID: K6630303X3S

Conclusion: The device complies with the MPE requirements by providing a safe separation distance of 0.89m between an antenna with a gain of 3 dBi, including any radiating structure, and any persons when normally operated . Proposed RF exposure safety information to include in User’s Manual: “FCC RF Exposure Requirements: CAUTION: The antenna(s) used for this transmitter must not be co-located or operating in conjunction with any other antenna or transmitter. This device is approved with emissions having a source-based time-averaging duty factor not exceeding 50%. These figures are based on a antenna having a 3 dBi gain. Failure to observe these restrictions will result in exceeding the FCC RF exposure limits. 9/17/2007 Page 3 of 3 FCC ID: K6630303X3S


Document Created: 2007-09-17 15:39:40
Document Modified: 2007-09-17 15:39:40
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