## Smart Route DataCollector RF Exposure Info - MPE Calculation DataCollector 915_2 Kenure Developments Ltd

#### Kenure Developments Ltd Smart Route DataCollector

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Document Description | RF Exposure Considerations |

Document Type | RF Exposure Info |

Document Title | Microsoft Word - MPE Calculation DataCollector 915_2.doc |

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KENURE DEVELOPMENTS LIMITED

THE COMPLETE DESIGN AND CONTRACT MANUFACTURE SERVICE

Registered Office: Springlakes Deadbrook Lane Aldershot Hampshire GU12 4UH

Tel: (01252) 338554 Fax:(01252) 329105

Registration No: 2265402

ISO 9001 GB13/87609

RF Exposure and Transmitter Power Considerations for

the DataCollector 915

FCC ID: Q8Q-SRDC

The FCC requires that the calculated MPE be equal to or less than a given limit

dependent on frequency

at a distance of 20 cm from a device to the body of a user.

The transmitter operation for the DataCollector 915 covers ISM 915 MHz, GSM 850 MHz

and PCS 1900 MHz operating bands.

The following FCC Rule Parts and procedures are applicable:

Part 1.1310 – Radiofrequency radiation exposure limits

Part 2.1091 – Radiofrequency radiation exposure evaluation: mobile devices

Part 15.247(b)(2) - The maximum peak conducted output power of the intentional radiator shall not exceed

the following: For frequency hopping systems operating in the 902–928 MHz band: 1 watt for systems

employing at least 50 hopping channels.

Part 15.247(b)(4) - The conducted output power limit specified in paragraph (b) of this section is based on

the use of antennas with directional gains that do not exceed 6 dBi.

Part 22.913(a)(2)

The ERP of mobile transmitters and auxiliary test transmitters must not exceed 7 Watts.

Part 24.232(c)

Mobile/ Portable stations are limited to 2 Watts EIRP peak power

KDB447498 D01 v05

Mobile and Portable Devices RF Exposure Procedures and Equipment Authorisation Policies

The MPE calculation as given in FCC OET Bulletin 65, page 19 is used to calculate the safe operating

distance for the user.

KENURE DEVELOPMENTS LIMITED

THE COMPLETE DESIGN AND CONTRACT MANUFACTURE SERVICE

Registered Office: Springlakes Deadbrook Lane Aldershot Hampshire GU12 4UH

Tel: (01252) 338554 Fax:(01252) 329105

Registration No: 2265402

ISO 9001 GB13/87609

MAXIMUM TRANSMITTER POWER CONSIDERATIONS

For ISM 915 MHz

Nominal Operating Frequency: 915 MHz

Number of Hopping Channels: 50

Max. Conducted Transmitter Power P = 28.0 dBm (631 mW) @ antenna socket

(measured).

Maximum specified antenna gain = 2.2 dBi

EIRP = 28.0 + 2.2dBm = 30.2dBm = 1047mW

Therefore the DataCollector 915 meets Part 15.247(b)(2) & 15.247(b)(4) conducted power limits (1 W).

For GSM 850 MHz

Transmitter frequency range = 824 MHz to 849 MHz

Conducted power = 33 dBm (2000 mW)

Maximum specified antenna gain = 2.0 dBi

EIRP = 33 + 2dBm = 35dBm = 3162mW

For Class 10 GPRS with 2 uplink timeslots, duty cycle = 25%

EIRP

eff

= 3162/4 = 791 mW

ERP = 35 -2.2 (dipole gain) = 32.8dBm = 1905mW

For Class 10 GPRS with 2 uplink timeslots, duty cycle = 25%

ERP

eff

= 1905/4 = 476 mW

Therefore the DataCollector 915 meets Part 22.913(a)(2) power limits (ERP 7 Watts).

Also the categorical exclusion provision of FCC Part 2.1091(c) applies as ERP

eff

< 1.5W

(with considerations of source based time averaging as per KDB 447498 Section 4.1(2))

KENURE DEVELOPMENTS LIMITED

THE COMPLETE DESIGN AND CONTRACT MANUFACTURE SERVICE

Registered Office: Springlakes Deadbrook Lane Aldershot Hampshire GU12 4UH

Tel: (01252) 338554 Fax:(01252) 329105

Registration No: 2265402

ISO 9001 GB13/87609

For PCS 1900 MHz

Transmitter frequency range = 1850 MHz to 1910 MHz

Conducted Power = 30 dBm (1000 mW)

Maximum specified antenna gain = 2.0 dBi

EIRP = 30 + 2dBm = 32dBm = 1585mW

For Class 10 GPRS with 2 uplink timeslots, duty cycle = 25%

EIRP

eff

= 1585/4 = 396 mW

Therefore the DataCollector 915 meets 24.232(c) power limits (EIRP 2 Watts).

Also the categorical exclusion provision of FCC Part 2.1091(c) applies as EIRP

eff

< 3.0W

(with considerations of source based time averaging as per KDB 447498 Section 4.1(2))

KENURE DEVELOPMENTS LIMITED

THE COMPLETE DESIGN AND CONTRACT MANUFACTURE SERVICE

Registered Office: Springlakes Deadbrook Lane Aldershot Hampshire GU12 4UH

Tel: (01252) 338554 Fax:(01252) 329105

Registration No: 2265402

ISO 9001 GB13/87609

MPE CALCULTIONS

The MPE calculation as given in FCC OET Bulletin 65, page 19 is used to calculate the

safe operating distance for the user.

S = EIRP/4 π R

2

Where S = Power density

EIRP = Effective Isotropic Radiated Power (EIRP = P x G)

P = Conducted Transmitter Power

G = Antenna Gain (relative to an isotropic radiator)

R = distance to the centre of radiation of the antenna (safe operating

distance)

For ISM 915 MHz

Values:

Transmitter frequency range = 902.5 MHz to 927.5 MHz

EIRP = 1047 mW

R = 20cm

Power Density Requirement

From table 1 (b) - Limits for General Population/ Uncontrolled Exposure of

FCC Rule Part 1.1310 for ISM 915 MHz

S = f/1500 mW/cm

2

(f = operating frequency)

S

req1

= 902.5/1500 = 0.61 mW/cm

2

(worst case)

Calculation:

S = EIRP/4 π R

2

S = 1047/(12.56 x 20

2

)

S

=

1047/(5024)

S

1

= 0.21mW/ cm

2

(<0.61 mW/cm

2

)

KENURE DEVELOPMENTS LIMITED

THE COMPLETE DESIGN AND CONTRACT MANUFACTURE SERVICE

Registered Office: Springlakes Deadbrook Lane Aldershot Hampshire GU12 4UH

Tel: (01252) 338554 Fax:(01252) 329105

Registration No: 2265402

ISO 9001 GB13/87609

For GSM 850 MHz

Values:

Transmitter frequency range = 824MHz to 849MHz

EIRP

eff

= 791 mW

R = 20cm

Power Density Requirement

From table 1 (b) - Limits for General Population/ Uncontrolled Exposure of

FCC Rule Part 1.1310 for 850MHz

S = f/1500 mW/cm

2

(f = operating frequency)

S

req2

= 824/1500 = 0.55 mW/cm

2

(worst case)

Calculation:

S = EIRP

eff

/4 π R

2

S = 791/(12.56 x 20

2

)

S

= 791/(5024)

S

2

= 0.16 mW/ cm

2

(<0.55 mW/cm

2

)

KENURE DEVELOPMENTS LIMITED

THE COMPLETE DESIGN AND CONTRACT MANUFACTURE SERVICE

Registered Office: Springlakes Deadbrook Lane Aldershot Hampshire GU12 4UH

Tel: (01252) 338554 Fax:(01252) 329105

Registration No: 2265402

ISO 9001 GB13/87609

For PCS 1900 MHz

Values:

Transmitter frequency range = 1850MHz to 1910MHz

EIRP

eff

= 396 mW

R = 20cm

Power Density Requirement

From table 1 (b) - Limits for General Population/ Uncontrolled Exposure of

FCC Rule Part 1.1310 for 1900MHz

S

req3

= 1.0 mW/cm

2

Calculation:

S = EIRP

eff

/4 π R

2

S= 396/(12.56 x 20

2

)

S

= 396/(5024)

S

3

= 0.079 mW/cm

2

(<1.0 mW/cm

2

)

KENURE DEVELOPMENTS LIMITED

THE COMPLETE DESIGN AND CONTRACT MANUFACTURE SERVICE

Registered Office: Springlakes Deadbrook Lane Aldershot Hampshire GU12 4UH

Tel: (01252) 338554 Fax:(01252) 329105

Registration No: 2265402

ISO 9001 GB13/87609

KDB447498 D01 v05 Section 7.2 SIMULTANEOUS TRANSMISSION

CONSIDERATIONS

Worst case summation of calculated MPE ratios for 915MHz and GSM or PCS

simultaneously transmitting transmitters.

ie: ΣMPE

ratios

= (S

1

/ S

req1

)

+

(S

2

/ S

req2

)

= (0.21/0.61) + (0.16/0.55)

= 0.35 + 0.29 = 0.64

Σ

of MPE ratios<1.0, so in accordance with KDB447498 Section 7.2, simultaneous

transmission test exclusion applies for the 915MHz and GSM/ PCS transmitters.

Conclusion

The required 20cm RF exposure limits for General Population/ Uncontrolled Exposure FCC Rule Part

15.247(b)(2), 22.913(a)(2) and 24.232(c) maximum transmitter power limits will not be exceeded for the

DataCollector 915 using antennas having a maximum gain of 2.2 dBi and 2.0 dBi for the ISM and GSM

antennas respectively.