RF Exposure

FCC ID: SK9CRUG1

RF Exposure Info

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FCCID_1186829

Model(s): C2SOR FCC ID: SK9CRUG1 IC: 864G-CRUG1

General Information:
Applicant: Itron Electricity Metering Inc.
ACS Project: 09-0255
FCC ID: SK9CRUG1
Device Category: Mobile
Environment: General Population/Uncontrolled Exposure
Exposure Conditions: Greater than 20 centimeters
Simultaneous Tx: Yes

Technical Information:
2.4GHz 2.4GHz GSM Modem CDMA Modem
Zigbee Zigbee Module Module
Radio 900 MHz LAN
(Register (Cell Relay FCC ID: N7NMC8790 FCC ID: N7N-MC5725
PCB) PCB) IC:2417C-MC8790 IC:2417C-MC5725
Antenna Type ¼ Wave Slot ¼ Wave Slot Patch Patch Patch
GSM850: 2.5 dBi CDMA850: 2.5 dBi
Antenna Gain 2.2 dBi 4.4 dBi 3 dBi
GSM 1900: 3.2 dBi CDMA 1900: 3.2 dBi
Conducted GSM 850: 31.8dBm CDMA 850: 25.13dBm
23.27dBm 15.00dBm -6.88 dBm
Power GSM 1900: 28.7dBm CDMA 1900: 24.84dBm
Maximum GSM 850: 2.69 W CDMA 850: 0.579 W
352 mW 87 mW 0.40 mW
EIRP GSM 1900: 1.54 W CDMA 1900: 0.636 W
GSM 850: 1.64 W CDMA 850: 0.353 W
Maximum ERP 214 mW 53 mW 0.24 mW
GSM 1900: 0.944 W CDMA 1900: 0.388 W

MPE Calculation:
Calculated Conducted Power (15.249) – Cell Relay 2.4GHz Zigbee Radio
For the purpose of determining Power Density for the 2.4GHz Zigbee radio on the Cell Relay PCB the
conducted RF power must first be calculated.

The power was calculated using the following equation:

P = (E ∗ d )
2

30 ∗ G
Where: G = Numeric Gain of the transmitting antenna with reference to an isotropic radiator
d = The distance in meters from which the field strength was measured
E = The measured maximum fundamental field strength in V/m

Table 1: Maximum Fundamental Field Strength
Uncorrected Corrected
Frequency Antenna Total Correction
Reading Reading
(MHz) Polarity (H/V) Factor (dB)
(dBμV/m) (dBμV/m)
2480 90.03 H 1.35 91.38

Table 2: Peak Output Power
Frequency Numeric Gain Distance Max. Fund. Field Output Power
(MHz) (m) Strength (V/m) (dBm)
2480 2.00 3 0.04 -6.88

5015 B.U. Bowman Drive Buford, GA 30518 USA Voice: 770-831-8048 Fax: 770-831-8598

Model(s): C2SOR FCC ID: SK9CRUG1 IC: 864G-CRUG1

Power Density
The Power Density (mW/cm2) is calculated as follows:
PG
S=
4πR 2
Where:
S = power density (in appropriate units, e.g. mW/cm2)
P = power input to the antenna (in appropriate units, e.g., mW)
G = power gain of the antenna in the direction of interest relative to an isotropic radiator
R = distance to the center of radiation of the antenna (appropriate units, e.g., cm)

Source Based Time Averaging of GPRS/EDGE Modem
The GPRS Modem is a Class 12 modem with a 50% source-based time averaged duty cycle.
The measured level was reduced by a factor 3dB to account for the duty cycle of the Modem. The
duty cycle correction factor is determined using the formula: 10log (0.50) = 3dB.

Corrected Level 850 = 31.8 – 3.0 = 28.8dBm
Corrected Level 1900 = 28.7 – 3.0 = 25.7dBm

MPE Calculator for Mobile Equipment
Limits for General Population/Uncontrolled Exposure*
Transmit Radio Power Radio Antenna Antenna
Distance Power Density
Frequency Power Density Limit Power Gain Gain (mW
(cm) (mW/cm^2)
(MHz) (dBm) (mW/Cm2) (mW) (dBi) eq.)
902.25 23.27 0.60 212.32 2.2 1.660 20 0.070
2405 15 1.00 31.62 4.4 2.754 20 0.017
2480 -6.88 1.00 0.21 3 1.995 20 0.000
824 28.8 0.55 758.58 2.5 1.778 20 0.268
1850 25.7 1.00 371.54 3.2 2.089 20 0.154
824 25.13 0.55 325.84 2.5 1.778 20 0.115
1850 24.84 1.00 304.79 3.2 2.089 20 0.127

Summation of Power Densities – Simultaneous Transmissions
This device contains multiple transmitters which can operate simultaneously and therefore the maximum
RF exposure is determined by the summation of power densities. The 900 MHz LAN and high power
Zigbee radio can not operate simultaneously there it is not appropriate to include both of those power
density values in the same summation of power densities. For the sake of providing the worst case data,
the highest power density from those two transmitters will be applied for the calculations.

The maximum power density as calculated by a summation of power densities for each simultaneous
transmission combination as follows:

GSM Modem Operating in the 800MHz Cellular Band:
900MHz LAN: 0.070 (mW/cm^2)
2.4GHz Zigbee: 0.017 (mW/cm^2)
GSM 850: 0.268 (mW/cm^2)
TOTAL: 0.355 (mW/cm^2)

GSM Modem Operating in the 1900MHz PCS Band:
900MHz LAN: 0.070 (mW/cm^2)
2.4GHz Zigbee: 0.017 (mW/cm^2)
GSM 1900: 0.154 (mW/cm^2)
TOTAL: 0.241 (mW/cm^2)

5015 B.U. Bowman Drive Buford, GA 30518 USA Voice: 770-831-8048 Fax: 770-831-8598

Model(s): C2SOR FCC ID: SK9CRUG1 IC: 864G-CRUG1

CDMA Modem Operating in the 800MHz Cellular Band:
900MHz LAN: 0.070 (mW/cm^2)
2.4GHz Zigbee: 0.017 (mW/cm^2)
CDMA 850: 0.115 (mW/cm^2)
TOTAL: 0.202 (mW/cm^2)

CDMA Modem Operating in the 1900MHz PCS Band:
900MHz LAN: 0.070 (mW/cm^2)
2.4GHz Zigbee: 0.017 (mW/cm^2)
CDMA 1900: 0.127 (mW/cm^2)
TOTAL: 0.214 (mW/cm^2)

Installation Guidelines:
The installation manual shall contain text similar to the following advising how to install the equipment to
maintain compliance with the FCC RF exposure requirements:

“RF Exposure (Intentional Radiators Only)
In accordance with FCC requirements of human exposure to radiofrequency fields, the radiating element
shall be installed such that a minimum separation distance of 20cm is maintained from the general
population.”

Conclusion:
This device complies with the MPE requirements by providing adequate separation between the device,
any radiating structure and the general population.

5015 B.U. Bowman Drive Buford, GA 30518 USA Voice: 770-831-8048 Fax: 770-831-8598

Document Created: 2009-09-30 16:05:51
Document Modified: 2009-09-30 16:05:51

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