18_BT228 RFExp

FCC ID: Q8WBT228

RF Exposure Info

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FCCID_4058896

RF Exposure evaluation

Product Description: Bluetooth Speaker
Model Number: BT228
FCC ID: Q8WBT228

According to 447498 D01 General RF Exposure Guidance v05 The 1-g and 10-g SAR test
exclusion thresholds for 100 MHz to 6 GHz at test separation distances ≤ 50 mm are
determined by: [(max. power of channel, including tune-up tolerance, mW)/(min. test
separation distance, mm)] ·[√f(GHz)] ≤ 3.0 for 1-g SAR and ≤ 7.5 for 10-g extremity SAR,
where
f(GHz) is the RF channel transmit frequency in GHz
Power and distance are rounded to the nearest mW and mm before calculation

According to the follow transmitter output power（Pt）formula：
Pt=（E x d）2/（30 x gt）
Pt=transmitter output power in watts
gt=numeric gain of the transmitting antenna (unitess)
E=electric field strength in V/m
d=measurement distance in meters (m)

According to the formula described above:
Emax=97.33dBuv/m=0.074V/m, d=3m, gt=1.12

Pt=（E x d）2/（30 x gt）=(0.074x3)2 / (30x1.12)=0.00146679W=1.47mW

The result is rounded to one decimal place for comparison

Worse case is as below: [2402MHz -1.47mW output power]

(1.47mW / 5mm)*[√2.402(GHz)] = 0.46 < 3.0 for 1 - g SAR

Then SAR evaluation is not required

NOTE: For the maximum power, you can refer FCC test report.

Document Created: 2019-09-17 19:29:37
Document Modified: 2019-09-17 19:29:37

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