MPE Report

FCC ID: ST2-IT104

RF Exposure Info

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FCCID_4096227

EUT: Clear Router
Report No: 0048-180813-01-FCC-IC Model: IT-104 FCC ID:ST2-IT104 IC:6012A-IT104

Per 2.5.2 Exemption Limits for Routine Evaluation – RF Exposure Evaluation
RF exposure evaluation is required if the separation distance between the user and/or bystander and the
device’s radiating element is greater than 20 cm, except when the device operates as follows:
• below 20 MHz and the source-based, time-averaged maximum e.i.r.p. of the device is equal to or less than 1
W (adjusted for tune-up tolerance);
• at or above 20 MHz and below 48 MHz and the source-based, time-averaged maximum e.i.r.p. of the device
is equal to or less than 4.49/f0.5 W (adjusted for tune-up tolerance), where ƒ is in MHz;
• at or above 48 MHz and below 300 MHz and the source-based, time-averaged maximum e.i.r.p. of the
device is equal to or less than 0.6 W (adjusted for tune-up tolerance);
• at or above 300 MHz and below 6 GHz and the source-based, time-averaged maximum e.i.r.p. of the
device is equal to or less than 1.31 x 10 -2 ƒ 0.6834 W (adjusted for tune-up tolerance), where ƒ is in MHz;
• at or above 6 GHz and the source-based, time-averaged maximum e.i.r.p. of the device is equal to or less
than 5 W (adjusted for tune-up tolerance).
In these cases, the information contained in the RF exposure technical brief may be limited to information that
demonstrates how the e.i.r.p. was derived.

CALCULATIONS

Given
E =  (30 * P * G) / d
and
S = E ^ 2 / 3770
where
E = Field Strength in Volts/meter
P = Power in Watts
G = Numeric antenna gain
d = Distance in meters
S = Power Density in milliwatts/square centimeter
Combining equations and rearranging the terms to express the distance as a function of the remaining
variables yields:
d =  ((30 * P * G) / (3770 * S))

Changing to units of Power to mW and Distance to cm, using:
P(mW) = P (W) / 1000 and
d (cm) =100 * d (m)
yields
d = 100 *  ((30 * (P / 1000) * G) / (3770 * S))
d = 0.282 *  (P * G / S)
where
d = distance in cm
P = Power in mW
G = Numeric antenna gain
S = Power Density in mW/cm^2
Substituting the logarithmic form of power and gain using: P
(mW) = 10 ^ (P (dBm) / 10) and
G (numeric) = 10 ^ (G (dBi) / 10)
yields
d = 0.282 * 10 ^ ((P + G) / 20) /  S Equation (1)
S = 0.0795 * 10 ^ ((P + G)/10)/ d^2 Equation (2)
where
Page 18 of 55
Advanced Compliance Laboratory, Inc. 210 Cougar Court, Hillsborough, NJ 08844, tel:(908) 927 9288

EUT: Clear Router
Report No: 0048-180813-01-FCC-IC Model: IT-104 FCC ID:ST2-IT104 IC:6012A-IT104

d = MPE distance in cm
P = Power in dBm
G = Antenna Gain in dBi
S = Power Density Limit in mW/cm^2

Equation (1) and the measured Output power is used to calculate the MPE distance.
Equation (2) and the measured Output power is used to calculate the Power density.

APPLICABLE LIMITS for separation >= 20cm

FCC: From §1.1310 Table 1 (B), for Public S = 1.0 mW/cm2 ; for Professional, S = 5.0 mW/cm2
IC: With formula of 1.31 x 10-2 ƒ 0.6834 W, more restricted EIRP limit value are 1.37W at 902MHz, 2.67W at
2400MHz.

RESULTS

No non-compliance noted.

For this EUT, P+G=23.98+3=26.98 dBm, and d=20cm

A. For FCC, plug all three items into equation (2), yielding,

Power Density Output Antenna] Power
Limit Power Gain Density
(mV/cm2) (dBm) (dBi) (mW/ cm2)
1.0/5.0 23.98 3 0.1

B. For IC, max. eirp= 0501W with max. 3dB gain antenna, much less than the limit of 1.37W.

NOTE: For mobile or fixed location transmitters, the minimum separation distance between the
antenna & radiating structures of the device and nearby persons is 20 cm, even if calculations
indicate that the MPE distance would be less.

Page 19 of 55
Advanced Compliance Laboratory, Inc. 210 Cougar Court, Hillsborough, NJ 08844, tel:(908) 927 9288

Document Created: 2018-11-09 15:59:33
Document Modified: 2018-11-09 15:59:33

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