RF Exposure

FCC ID: EHA-BTM312

RF Exposure Info

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FCCID_1569142

CV30 802.11bg, BT collocated TX RF Exposure Technologies Corporation Dave Fry EMC Test Laboratory Sr. EMC Engineer Cedar Rapids, IA Date: Sept. 20, 2011 cm inches EIRP Calculation of RF Exposure 20.0 7.87 CRF 47 Part 15.247 (b)(5) (b)(5) Systems operating under the provisions of this section shall be operated in a manner that ensures that the public is not exposed to radio frequency energy levels in excess of the Commission's guidelines. See Sec. 1.1307(b)(1) of this chapter. System Description The CV30 is a mobile computer. The unit contains WLAN and Bluetooth radios. FCC ID: EHADRCB 802.11 bg FCC ID: EHA-BTM312 Bluetooth The radios all transmitt on separate antennas. Radio Disc / Rule MHz - MHz Watts (Conducted) CV30 802.11bg radio FCC ID: EHADRCB 15C 2412 2462 0.078 Bluetooth Radio FCC ID: EHA-BTM312 15C 2402 2480 0.0076 Table 1 in 47 CFR 1.1310 defines the maximum permissible exposure (MPE) for the general population. The exposure level at the distance listed from the EUT’s transmitting antenna is calculated using the general equation: The exposure level at a 20 cm distance from the EUT’s transmitting antenna is calculated using the general equation (See OET 65, Page 19, Eq. 4): S = (PG)/4(PI)R² Where: S = power density (mW/cm²) P = power input to the antenna (mW) G = numeric power gain relative to an isotropic radiator R = distance to the center of the radiation of the antenna (20 cm = limit for this MPE estimate) PG = EIRP Solving for S, the maximum power densities 20 cm from the transmitting antennas are summarized in the following tables: Calculation of RF Exposure cm inches 20.0 7.87 802.11bg Radio CV30 antenna with highest power frequency band worst case EIRP FCC ID: EHADRCB IC: 1223A-DRCB Calculation for exposure at 20cm distance Pwr Density Pwr Density Peak @ 20cm Limit Conducted Antenna Antenna Part Transmit Freq. Power Gain Power Antenna Description Type No. (MHz) (mW) (dBi) mW/cm2 mW/cm2 Density Ratio Intermec CV30 linear panel 2450 78.0 3 0.0310 1.0 0.0310 Bluetooth CV30 Bluetooth chip antenna worst case EIRP FCC ID: EHA-BTM312 IC: 1223A-BTM312 Calculation for exposure at 20cm distance Pwr Density Pwr Density Peak @ 20cm Limit Conducted Antenna Antenna Part Transmit Freq. Power Gain Power Antenna Description Type No. (MHz) (mW) (dBi) mW/cm2 mW/cm2 Density Ratio on board chip linear NA 2450 7.6 2 0.0024 1.0 0.0024 Page 1 of 2

CV30 802.11bg, BT collocated TX RF Exposure Technologies Corporation Dave Fry EMC Test Laboratory Sr. EMC Engineer Cedar Rapids, IA Date: Sept. 20, 2011 cm inches EIRP Calculation of RF Exposure 20.0 7.87 Co-Located Transmitter Calculation of RF Exposure Per FCC TCB Training April 3, 2002 “Devices operating in multiple frequency bands When RF exposure evaluation is required for TCB approval Separate antennas – estimated minimum separation distances may be considered for the frequency bands that do not require evaluation or TCB approval, however, the estimated distance should take into account the effect of co-located transmitters. (Note 24) Note 24 According to multiple frequency exposure criteria, the ratio of field strength or power density to the applicable exposure limit at the exposure location should be determined for each transmitter and the sum of these ratios must not exceed 1.0 for the location to be compliant.” Worst Case Exposure for CV30 with WLAN and BT when using co-located transmitters. Calculation for exposure at 20cm distance Pwr Density Pwr Density Peak @ 20cm Limit Conducted Transmitter FCC ID: Antenna Antenna Part Transmit Freq. Power Gain Power Antenna Description Type No. (MHz) (mW) (dBi) mW/cm2 mW/cm2 Density Ratio FCC ID: EHADRCB CV30 linear linear panel 2450 78.0 3 0.0310 1.0 0.0310 FCC ID: EHA-BTM312 Internal chip chip NA 2450 7.6 2 0.0024 1.0 0.0024 ratio limit Total 1.0 0.0334 The worst case configuration for all combinations of co-located transmitters and antennas are shown. In all cases the ratio of exposure compared the limit when totaled does not exceed 1.0. The WLAN and Bluetooth radio transceivers are mobile transmitters and are greater than 5 cm from each other and all other simultaneous transmitting antennas. "KDB 447498 D01 Mobile Portable RF Exposure v04" provides the procedures, requirements, and authorization policies for mobile and portable devices. Item #8 best fits the exposure condition described in this report. Since these mobile devices are categorically excluded from routine evaluation; per footnotes 1 and 33 of KDB 447498, simple calculations may be used to estimate the power density to demonstrate compliance with 47 CFR 1.1310 requirements. The estimate above shows MPE limits are met for simultaneous transmission at a 20cm boundary. Page 2 of 2


Document Created: 2011-10-04 11:34:45
Document Modified: 2011-10-04 11:34:45
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