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There have been 8 comment(s) made on this document:
  • Tim Harrington commented on 2009-11-06 19:41:48.59:

    A) For the Nov 5 2009 1:49PM John Welch comments:

    We anticipate revising appropriately; please note also that KDB 447498 item 2) b) ii) (1) requires a single fixed probe position only, well within the capability of SAR systems, and as a part of the specific relative-level testing while device spacing is varied.

    B) For the Nov 4 2009 10:15AM John Forrester comments:

    1) To our recall this topic was considered during past periodic discussions with TCBs, for example leading to July 2008 version of KDB 447498. Regardless, we will review text to determine whether other changes may be appropriate.

    2) As discussed during the October 2009 TCB workshop, the supplemental procedures to KDB 616217 apply for both laptop / notebook / netbook computer and tablet computer host platforms. Parties are encouraged to use the KDB 616217 supplemental procedures where applicable to reduce subsequent unnecessary test and permissive change requirements. However, while use of the generic procedures in KDB 447498 is not precluded for tablet computers, parties must not mix the original and the new supplemental procedures as these can cause administrative and other technical issues due to many of the previous host-specific permissive-change approvals.

    3) We will review text to determine whether other changes may be appropriate.

    4) As discussed during the October 2009 TCB workshop, such device configurations and exposure conditions may apply certain not-source-based low transmission duty factor considerations; however SAR testing is not applicable for device positioned at arbitrary separation distances.

    5) As discussed during the October 2009 TCB workshop, for such device configurations and exposure conditions certain interim policies and recommendations are provided but uniform procedures for inclusion in KDB publications are not established.

    C) For the Oct 28 2009 7:20PM Mike Kuo comments:

    We confirm and anticipate revising accordingly.

    D) For the Oct 16 2009 3:17PM Mike Kuo comments:

    As discussed in the October 2009 TCB workshop, the supplemental laptop / notebook / netbook procedures to KDB 616217 should assuage many of the existing issues described in your attachment.  It was suggested during the TCB workshop and we plan to include additional guidance on how to test for conservative SAR configurations. This could be included as an appendix to the supplemental document to KDB 616217.

    E) For the Oct 16 2009 3:14PM David Case comments:

    We will consider these suggestions in the next revisions of KDB 248227, and KDB 447498 where applicable. To our understanding 802.11n was finalized under the IEEE process as of Sep. 2009. As the official publication becomes available we will begin considering the issues and changes then work on revising the existing 802.11 and MiMo SAR testing guidance accordingly.

  • John Welch commented on 2009-11-05 13:49:38.186:
    These comments submitted on behalf of Motorola, Inc.
     
    Comments on Section 2 b) ii 1: Motorola recommends changing the fixed distance from one half the probe tip diameter to the distance equivalent of that used during the zoom scan measurement. The rationale for this recommendation is that specifying one half probe tip diameter distance could introduce higher measurement uncertainty due to boundary effects and physical damage to fragile high frequency probes whose tip diameter is 2.5 mm.
  • John Forrester commented on 2009-11-04 10:15:31.15:
    1. The wording in Section 2, “The 1-g SAR must be < 1.2 W/kg for all configurations”, implies many portable devices with SAR>1.2 require a PBA. Does this mean a notebook or tablet is a KDB if the SAR is >1.2mW/g? Recommendation: Clarify that this section is applicable for devices not covered in other KDBs such as 616217. 2. Are tablets also included in Section 3)b)ii)(2)? 3. Section 2 and 3 are very specific to transmitters that do and don’t allow simultaneous transmission. It can be confusing to determine the overall requirements for a transmitter that does allow simultaneous transmission. Recommendation: Add a line in section 3 along the lines of “Transmitter and module are first evaluated in reference to section 2 prior to evaluation of simultaneous considerations in this section” 4. It is unclear how portable devices with a “hand held” only usage model should be tested. An example is an eBook reader where the transmitter is only used to sporadically access the internet for main purpose of downloading books, newspapers and magazines. The usage model is that the device is held in the hand when the radio is actively used to purchase a new book. The remainder of the time the radio is equivalent to an idle mobile phone and either never transmits or is limited to short duration network traffic transmissions where the device is compliant with RF safety requirements through exemption or very low average power. This same user model can be true for other products such as portable gaming devices that are held in the hand during use. In both of these scenarios, the product is designed for usage such that the antenna is away from the user and thus is easily compliant with the SAR limit with a small separation distance. Most WLAN/WWAN transmitters would fail the FCC SAR limit with 0cm separation distance to the antenna but this configuration is not representative of the usage model for these device types which are “near body” but not “body worn” as 0cm separation distance would support. Recommendation: Adding wording in section 4)c) for devices intended for hand held operation should be tested for body SAR with a 1.5 cm separation distance consistent with body SAR requirements in Appendix D of OET65C or evaluated for hand SAR per 4)c)iii)(1). 5. Many devices that could be evaluated under Section 4)c)iii)(3) (hand-held and used <5cm from body) will be challenged to meet the FCC body SAR limit if tested with a 0cm separation distance and assumed transmissions characteristics to those of a cellular phone. Reducing the transmit power for SAR compliance is often not an available option due to minimum maximum transmit power limits specified by wireless carriers. For example, most wireless carriers have total radiated power (“TRP”) requirements that must be met to ensure a good user/network experience. Consideration should be given to the application specific transmission characteristics that are set either through the network and/or via device level mechanism such as connection managers. Such approaches would result in reducing the transmitter duty cycle and therefore the average transmit power to the extent that the device readily complies with RF exposure requirements. Recommendation: Add wording in KDB 447498 that “device transmit duty cycle reduction techniques” or “device dynamic maximum transmit power” algorithms can be used in demonstrating compliance with SAR requirements. It is understood that any proposed technique would require FCC review unless adopted in a formal transmission standard (e.g. 3GPP/3GPP2, IEEE, etc) as “source based time averaging”
  • George Tannahill commented on 2009-10-30 13:06:54.31:
    The expiration date of this inquiry was incorrectly changed from 11/6/09 to 11/16/09. The expiration date has been corrected to 11/6/09.
  • Mike Kuo commented on 2009-10-28 19:20:22.186:

    Section 2)b)ii)2) :

    (2) When the device position in item 2) b) ii) (1) with the highest point SAR is > 25% of that measured at the initial position, a complete 1-g SAR evaluation is required for this configuration.
     
    Comment: With confirmation from FCC, the intended requirement should be " with the highest point SAR is > 125% (1.25) of that measured at the inital position, a complete 1-g SAR evaluation is required for this configuration."
  • Mike Kuo commented on 2009-10-16 15:17:21.373:
    Dear FCC:
     
    Attached please find SAR measurement procedure proposal to utilize KDB 447498 section 2)a)i) to reduce number of SAR evaluations and permissive change filings:
     
    Best Regards
     
    Mike Kuo / CCS
    View attachment associated with this comment
  • David Case commented on 2009-10-16 15:14:59.61:

    1)      Under General requirements the document states that when applicable KDB # 248227 should be used for 802.11a/b/g for antenna diversity. Given the fact that 802.11n products have been approved and that it uses the same modulation OFDM as 802.11g / a (except for BW), should this document also not refer to using KDB 248227 for 802.11n  testing. at least for initial reference.  Note;  In reviewing KDB 248227, one set of  missing information that needs to be added includes the 802.11n channel sets for the 5470-5725 MHz, these are listed in the current version of the standard..  

     

    2)   In addressing MiMo and beam forming antennas, it currently states one needs to discuss the testing with the FCC lab.  In order to insure uniform testing  across all product lines by all manufacturers and given that the current IEEE 1528 standards does not address the issue at this time, will the FCC be issuing further guidance on MiMo and beam forming testing in the near future?

  • David Case commented on 2009-10-16 08:51:00.54:
    1)      Under General requirements the document states that when applicable KDB # 248227 should be used for 802.11a/b/g for antenna diversity. Given the fact that 802.11n products have been approved and that it uses the same modulation OFDM as 802.11g / a (except for BW), should this document also not refer to using KDB 248227 for 802.11n  testing. at least for initial reference.  Note;  In reviewing KDB 248227, one set of  missing information that needs to be added includes the 802.11n channel sets for the 5470-5725 MHz, these are listed in the current version of the standard..  
     
    2)   In addressing MiMo and beam forming antennas, it currently states one needs to discuss the testing with the FCC lab.  In order to insure uniform testing  across all product lines by all manufacturers and given that the current IEEE 1528 standards does not address the issue at this time, will the FCC be issuing further guidance on MiMo and beam forming testing in the near future?

Note: It is important to understand that the staff guidance provided in the KDB is intended to assist the public in following Commission requirements and does not constitute rules. Accordingly, the guidance is not binding on the Commission and will not prevent the Commission from making a different decision in any matter that comes to its attention for resolution.