50 FR 36061
`
`September 5, 1985
`
`Rules and Regulations
`
`Reporter
`50 FR 36061
`
`Federal Register > 1985 > September > September 5, 1985 > Rules and Regulations > FEDERAL
`REGISTER
`
`Title: Overall Revision of the Rules Regarding Industrial Scientific and Medical (ISM) Equipment
`
`Action: Final rule.
`
`Agency
`
`FEDERAL REGISTER
`
`Identifier: [Gen. Docket No. 20718; FCC 85-445]
`
`Administrative Code Citation
`
`47 CFR Parts 0, 2, and 18
`
`Synopsis
`
`SUMMARY: The FCC amends Part 0 (dealing with the organization and function of the Commission),
`Part 2, Subparts I and J (dealing with the marketing rules and equipment authorization procedures), Part
`18 of its Rules (dealing with industrial, scientific, and medical (ISM) equipment) by deleting
`administrative provisions which have become burdensome and obsolete and providing four additional
`frequency bands exclusively for the operation of ISM equipment. The intended effect is to provide a more
`efficient equipment authorization program for ISM devices, more comprehensive regulations, uniform
`methods of measurements, and provisional technical standards for RF lighting devices.
`
`Text
`
`SUPPLEMENTARY INFORMATION:
`
`Samsung Electronics Co., Ltd. v. Demaray LLC
`Samsung Electronic's Exhibit 1055
`Exhibit 1055, Page 1
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`50 FR 36061
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`Regulations
`
`List of Subjects
`
`47 CFR Part 0
`
`Organization and functions.
`
`47 CFR Part 2
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`Imports.
`
`47 CFR Part 18
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`Business and industry, Household appliances, Medical devices, Scientific equipment.
`Third Report and Order
`In the matter of overall revision of the rules regarding industrial, scientific, and medical (ISM)
`equipment under Parts 0, 2, and 18, Gen. Docket No. 20718.
`By the Commission: Commissioner Quello concurring in the result.
`
` nIntroduction and Summary*
`n* Footnotes appear after signature.
`
`1. This proceeding was initiated to revise the regulations concerning industrial, scientific, and medical
`(ISM) equipment under 47 CFR Parts 0, 2, and 18.(1)(2) These rules were adopted in 1946 in
`order to protect radiocommunication services from receiving interference from the operation of
`ISM equipment. In light of the changes in spectrum allocation and the proliferation of ISM
`equipment as well as radiocommunication services, we questioned whether some of the
`regulations adopted in 1946 were still adequate. We started by releasing several notices inquiring
`into the suitability of the prescribed technical standards, methods of measurements, and the
`effectiveness of the equipment authorization and enforcement program.(3) We continued, in
`response to comments filed on these notices, and based on our experience in dealing with ISM
`equipment, and in view of the continued rarity of incidences of interference from the operation of
`such equipment, by amending the technical standards only for induction cooking ranges and by
`deleting the requirement for filing the Form 724.(4) We then proceeded by issuing a Third Notice
`of Proposed Rule Making(5) (Notice) addressing the following topics: (1) the adoption of a more
`liberal and efficient equipment authorization program, (2) the deletion of burdensome and
`obsolete administrative rules, (3) the addition of four ISM frequency bands, (4) technical
`standards for RF lighting devices, and (5) the implementation of uniform methods of
`measurements.(6)(7) In the Notice, we indicated that the general technical standards would be
`revised when further study has been undertaken. We are also seeking more information from the
`CCIR and CISPR, (8) which, in Resolution 63 of the 1979 Geneva World Administrative Radio
`Conference (WARC), were invited to collaborate in preparing a recommendation on the emission
`limits from ISM equipment.
`
`2. Comments on the Notice are very supportive of the Commission's proposal. The consensus is that a
`more liberal authorization program is justified when dealing with an established industry and that
`the current technical standards are adquate to control electromagnetic interference from classical
`ISM equipment (large industrial machines, scientific and medical apparatus). However,
`commenters have requested minor changes and some clarification in the area of: (1) terminology
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`Ex. 1055, Page 2
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`50 FR 36061
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`and definitions used under Part 18, (2) equipment authorization requirements and enforcement,
`and (3) methods of measurements. This Order takes into account, to the extent practicable, the
`comments filed in response to the Notice and amends the rules accordingly.(9) A list of the
`commenters is given in Appendix A of this document. The new rules and measurement
`procedures adopted herein are contained in Appendices B and C, respectively.
`
`Restructure of Part 18 and Terminology
`
`3. The Rules governing ISM equipment under Part 18, especially with respect to the
`administrative provisions, have grown complex and quite difficult for the layman to
`comprehend. In the Notice, we proposed to rewrite Part 18 in its entirety and organize it
`into only three subparts rather than the nine subparts to the old Part 18. We believe that
`this would yield a better understanding of the rules, and decrease publication costs by
`reducing the length of the text (by about 40%). The intricacy of Part 18 primarily results
`from the amendments to 47 CFR Part 2 dealing with the administrative rules for all
`equipment regulated by the Commission and from the development of new technologies
`which have rendered inappropriate some of the definitions and terminology used. No
`objections to the new format were voiced, but a few changes to the terminology used were
`requested. The American Telephone & Telegraph Company (AT&T) notes that the latest
`amendments to § 2.1 with regard to the definition of "ISM equipment" and "harmful
`interference" have not been reflected in § 18.107.(10) We agree that the definitions in Part
`18 should be consistent with the ones used under Part 2 and are rewording § 18.107
`accordingly. In response to the National Electrical Manufacturers Association (NEMA)
`comments, we clarify that, for the purposes of our rules, ISM equipment only includes
`machines which generate RF energy from 9 kHz to 3 THz (3,000 GHz) for non-
`telecommunication purposes. Equipment which operates and generates energy below 9
`kHz or above 3 THz is not included under this definition. We also affirm, in response to
`Dash, Strauss and Goodhue's (DSG) comments, that nuclear magnetic resonance
`equipment which generates RF energy and is used for identifying and determining the
`structure, conformation, and movement of molecules and their phases in the fields of
`medicine, chemistry, and physics, fall under the category of general ISM equipment.(11)
`Other comments of an editorial nature have also been considered and are acknowledged, to
`the extent possible, as shown in Appendices B and C.
`
`Applications and Authorizations
`
`4. In the Notice, we reported that difficulties in implementing the administrative regulations
`have evolved, especially because of the complexity of the equipment authorization
`program.(12) We proposed to solve these problems by simplifying the regulations and by
`deleting burdensome and obsolete rules. The intended effect is to institute a more
`comprehensible authorization and enforcement program and to increase the efficiency of
`our service to the public. The comments received endorse the changes proposed by the
`Commission. Inquiries have been made on the possibility of expanding the verification
`procedure for certain devices, relaxing the labeling requirements, and on the authorization
`procedures applicable to microwave ovens and RF lighting devices.
`
`A. Equipment Authorization
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`Ex. 1055, Page 3
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`5. Most ISM equipment is required to be authorized as meeting the pertinent technical
`standards, in accordance with one or more of the following procedures: (1) type approval,
`(2) on-site certification, and (3) prototype certification.(13) Confusion, however, has been
`caused by the fact that all three procedures, in some cases, can be applied to the same
`equipment. For instance, the same ultrasonic device can either be type approved, certified
`on-site by a competent engineer, or prototype certified by the Commission. Further adding
`to the complexity, the Commission imposes a triennial recertification requirement for
`certain ISM equipment (See § 18.142); manufacturers or operators must have their devices
`retested every three years by a competent engineer to assure continued compliance. In the
`Notice, we proposed to simplify the equipment authorization program by placing all ISM
`equipment under notification except for consumer products which would be subject to
`certification, and for one-of-a-kind equipment and ultrasonic devices operating below 90
`kHz with less than 500 watts which would be verified. We also suggested to continue type
`approval only for consumer microwave ovens and to delete the triennial certification
`requirement.(14)
`
`6. The comments received are very supportive of the proposed program. The General Electric
`Company (GE), NEMA, and the International Business Machines Corporation (IBM)
`suggest that verification be extended to "large unwieldy" equipment and/or "custom-built
`devices in small quantities". GE, NEMA, and IBM state that verification would ease the
`testing requirements on manufacturers for large equipment built in small volume which
`has repetitive applications; the operator could assume the responsibility of testing the
`equipment, in some instances. Verification, IBM mentions, would also permit operators to
`modify their devices a few years after installation (as is often the case) without having to
`request any authorization from the Commission. Notification in such cases, the
`commenters believe, would not be cost effective since tests would have to be performed on
`similar equipment and authorization from the FCC would also have to be obtained,
`possibly creating a marketing delay.
`
`7. The vast majority of nonconsumer ISM devices are in fact large and unwieldly and are
`typically built in low quantities. Therefore, the manufacturers' comments are interpreted as
`requesting that virtually all nonconsumer ISM equipment be placed under verification. In
`retrospect, it appears that there is much to be gained by doing so and little reason not to. It
`is now clear that attempting to distinguish whether an equipment should be verified or
`notified on the basis of whether it is "one-of-a-kind" would only lead to confusion, and
`consequently, there would likely ensue numerous requests for interpretation of the rules.
`For the kind of equipment involved here, where manufacturers have had a long history of
`compliance and the equipment changes little from year to year, notification would provide
`little information of use to the Commission. Accordingly, we are placing all nonconsumer
`ISM equipment into the verification category. As explained later in the discussion of the
`measurement procedures, manufacturers may either verify equipment for a given
`installation or, if a suitable measurement site is used, can verify compliance by performing
`tests on only one unit of an equipment which is representative of units produced
`subsequently. Consumer ISM equipment will be subject to certification as proposed. We
`shall also permit the operation of equipment, to determine customer acceptability, prior to
`the receipt of grants from the Commission, to avoid marketing delays.(15) See Appendix
`B, § 2.809. Also for certified equipment, when the same or essentially the same model will
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`be marketed under more than one trade name, we shall require reports of measurements
`only for the basic device; such a procedure will be referred to as a multiple listing. See
`Appendix B, §§ 18.203 through 18.211.
`
`8. R&B Enterprises (R&B), a test facility, suggests that the Commission impose a triennial
`reverification requirement to assure continued compliance with the regulations. R&B
`states that no burden would be placed on the operator since the tests are relatively easy and
`inexpensive (around $5,000 each). We disagree. Many manufacturers and operators have
`found that one of the most burdensome regulations under Part 18 is the requirement to
`retest equipment at predetermined intervals.(16) The Commission through experience has
`found it unnecessary to require manufacturers or operators to test their equipment at fixed
`time intervals when dealing with mature industries.(17) There is nothing in the record to
`indicate that any useful purpose would be served by placing such a requirement on
`manufacturers or operators of ISM equipment.
`
`9. In the Notice, we proposed to continue type approval for microwave ovens because the
`measuring instrumentation needed to evaluate such equipment has not been commercially
`available for more than a decade. More precisely, the present FCC methods of
`measurements call for the use of field intensity meters (FIMs) with linear amplifiers and
`average reading detectors which are no longer manufactured.(18) The Commission
`initially started type approving microwave ovens due to the unfamiliarity of the industry
`with the pertinent test methodology and techniques for achieving compliance. Over the
`years, the industry has matured and we feel today that there is sufficient familiarity with
`the test procedures. Manufacturers have had little difficulty in achieving compliance. This
`is evidenced by the high rate of compliance found in our type approval tests. Nevertheless,
`the type approval procedure has been maintained because of the limited availability of the
`necessary measuring instrumentation and the complexities involved in establishing an
`alternate test procedure. We have learned, however, that suitable measurement equipment
`is once again available on the market.(19) Certification, instead of type approval, can thus
`be applied to consumer microwave ovens. While we anticipate that some manufacturers
`have enjoyed the benefit of no mandatory requirement to test the equipment themselves,
`we do not see this service as a reason to continue type approval. The Commission will start
`accepting applications for certification immediately, but to allow manufacturers enough
`time to make arrangements for having measurements performed, we shall continue to type
`approve consumer microwave ovens until September 1, 1986.
`
`10. In response to some questions raised on the applicable equipment authorization procedures
`for RF lighting devices, we clarify that devices marketed and/or used for general purpose
`or consumer applications will be subject to certification. All other RF lighting devices will
`be subject to verification. The new equipment authorization requirements are specified in
`Appendix B under § 18.203.
`
`B. Equipment Identification
`
`11. As proposed in the Notice, we shall require that certified equipment carry an FCC
`identifier. No other labeling requirements will be imposed. We believe that requiring
`manufacturers to include information about the interference potential of their equipment in
`the instruction manual is sufficient to warn the operator. Also, in the past we have found
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`that a label placed on the device itself is often misinterpreted by the layman as being a
`warning against radiation which is hazardous to human life. No objections to our proposal
`have been voiced.
`
`C. Miscellaneous Regulations
`
`12. In the Notice, we concluded that §§ 18.21-18.29, which state that ISM equipment not in
`conformance to Part 18 requirements may only be operated with a license, were obsolete
`and could be deleted. Licensing of ISM devices, if necessary, can only be made under Part
`5 of the Rules on an experimental basis. Based on the fact that the Commission has never
`issued a license for ISM equipment for non-experimental purposes and that no objections
`to the discontinuation of these regulations have been made, we are deleting §§ 18.21-
`18.29.
`
`Technical Standards
`
`13. Although the revision of the technical standards is not the primary area of interest of this
`proceeding, we did request comments in the Notice on whether additional technical
`standards are needed as a result of the opening of four new ISM frequency bands, and on
`what interim standards should be imposed for RF lighting devices. Other subjects of a
`technical nature which were raised in the comments are also addressed below.
`
`A. Addition of Four ISM Bands
`
`14. In the Notice , we proposed no in-band limits for the four new ISM frequency bands. Out-
`of-band emissions were to be the same as apply already to that particular type of
`equipment. We requested comments on the suitability of such standards, particularly, with
`regard to ISM equipment at 6.78 MHz # 15 kHz which, in accordance with footnote 524 of
`the U.S. Table of Frequency Allocations, must be made with the coordination of other
`administrations whose services might be affected. No objections were received from the
`Interdepartment Radio Advisory Committee, which oversees U.S. Government use of the
`spectrum or from other possibly concerned parties. Spectrum Measurement Corporation
`(SMC) requested an additional ISM frequency. However, SMC's request exceeds the scope
`of this proceeding as we previously mentioned in footnote 9, supra.
`
`B. RF Lighting Devices
`
`15. RF lighting is a term which applies to a new technology whereby radio frequency (RF)
`energy is used to produce light more efficiently. Of concern to the Commission is the
`potential for a small portion of that energy escaping into space and causing radio
`interference. With the frequencies currently utilized by RF lighting devices, AM broadcast
`is the most likely candidate to receive interference. Most RF lighting products operate
`under the conditions of a waiver.( 20 ) The waiver pertains to the triennial certification
`requirement of § 18.142. As a condition of the waiver, the Commission imposes the
`technical standards specified under Part 15, Subpart J, instead of the ones under Part 18. In
`order to study further the effects of RF lighting devices on radiocommunication, we have
`issued a Notice of Inquiry in Gen. Docket 83-806.( 21 ) In the Notice, we proposed to
`delete the triennial certification requirement of § 18.142 and at the same time adopt only
`one set of technical standards for RF lighting devices in order to simplify the rules,
`pending further action in Gen. Docket 83-806. The standards which we find to be the most
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`suitable to protect the radiocommunication services, for the time being, are the ones
`specified under Part 15, Subpart J.
`
`16. NAB, which represents the interest of the majority of the AM broadcasting community,
`feels that such a proposal would still be inadequate to deter incidences of interference to
`AM radio reception because it would not impose field strength limits below 30 MHz. NAB
`believes that "at minimum, an appropriate limit should be 25 m V/m at a distance of 10
`meters" for frequencies below 30 MHz.( 22 ) Other parties affected by the rules on RF
`lighting devices, such as NEMA and GE, support the Commission's proposal. GE and
`NEMA also advocate the possibility of establishing voluntary industry standards with the
`cooperation of NAB and have submitted to the Commission several reports on the progress
`made in their studies. The data filed by NEMA and GE have been incorporated in Docket
`83-806 and will be considered in that proceeding.
`
`17. Although the concerns of NAB are understandable, we disagree with imposing a fixed
`radiated emission limit of 25 m V/m at 10 meters for frequencies below 30 MHz. We do
`not dispute the need for controlling radiation from RF lighting devices; however,
`insufficient information has been submitted as to whether a radiated emission limit is
`indeed necessary below 30 MHz, and what limit might be appropriate. NAB does not
`provide any in-depth analysis of the potential problems. We note, for example, that the
`man-made radio noise below 30 MHz is very high and that a field strength limit of 25 m
`V/m at 10 meters might be too stringent at certain frequencies to permit the effective
`operation of RF lighting products.( 23 )
`
`18. The emission limits under Part 15, Subpart J, which were adopted to control the
`electomagnetic interference from digital or computing devices to radiocommunication
`services, seem to be serving the same purpose, for the moment, when they are applied to
`RF lighting devices. We have not received, to this date, any reports of interference from
`the operation of RF lighting devices to radiocommunication services when the technical
`standards of Part 15, Subpart J are met. For the reasons given above, we shall adopt in this
`proceeding the technical standards of Part 15, Subpart J for RF lighting devices, pending
`further development in Gen. Docket 83-806. The question of radiation limits below 30
`MHz, which has also been raised by GE and NEMA in their comments in Gen. Docket 83-
`806, will be addressed with more depth in that docket.( 24 )
`
`C. Miscellaneous
`
`19. In an open meeting with the Commission staff held on August 21, 1984, manufacturers of
`medical diagnostic ultrasonic equipment expressed their desire to have such equipment
`exempted from Part 18. This matter is currently under review and further action is
`expected in the near future. In the meantime, the relaxation in the equipment authorization
`requirements from type approval to verification for such equipment will ease the burden of
`these rules. The Ultrasonic Industry Association, Inc. (UIA) which represents major
`manufacturers of ultrasonic equipment, and other parties, filed comments in this docket
`requesting that the radiated emission limits for such equipment be deleted, retaining only
`limits for line conducted emissions. The reasons given by the commenters are that
`ultrasonic devices which meet the prescribed conduction limits seldom exceed the
`radiation limits. Reference is also made by UIA to the First Notice in this proceeding in
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`which we proposed to exempt from the out-of-band radiated emission limits ultrasonic
`equipment which would comply with the conducted RF voltage limits in the 9 kHz to 30
`MHz frequency range. Also, we indicated in the First Notice that proof of compliance
`with the out-of-band radiated emissions would only be necessary when requested by the
`Commission.( 25 ) The test data accumulated by the FCC laboratory show that the nature
`of the emissions from ultrasonic equipment is such that compliance with the conduction
`limits has always led to conformance with the radiation limits below 30 MHz. We,
`therefore, see no objection to accommodating UIA's request.
`
`20. The Aerospace and Flight Test Radio Coordinating Council (AFTRCC), in light of the low
`likelihood of interference, and the characteristics of the environment of use, feels that ISM
`equipment at aerospace manufacturing plants should be exempt from the testing
`procedures and the emission limits in Part 18. We cannot exempt such equipment from the
`technical standards, as requested by AFTRCC, without explicit studies demonstrating that
`noncompliance with Part 18 will not be a threat to radiocommunication services. The low
`incidence of interference reports cannot be the sole determining factor for granting an
`exemption. The only assumption we can make from AFTRCC's comments is that their
`systems have not been a source of interference because they have been operating in
`compliance with Part 18.
`
`21. IBM raises the issue of dual or multiple regulations for certain devices it manufactures.
`More precisely, IBM is concerned that two different sets of standards may be applied to its
`computer plasma displays (CPDs). A CPD is a special type of video monitor intended to
`be used as a peripheral for a computer. The image on the screen is generated by applying
`radio frequency (RF) energy to gases in the "picture tube" in order to ionize those gases.
`IBM is concerned that, since the equipment utilizes RF energy to ionize a gas, it might be
`considered as subject to the requirements in Part 18. On the other hand, since the device is
`basically a peripheral for a computer, it also appears to be subject to the emissions limits
`for computing devices in Part 15, Subpart J. IBM feels that CPDs are much more akin to
`conventional computer monitors than ISM equipment and asserts that only the computer
`rules should apply. IBM notes that the computer standards are generally more stringent
`than those for ISM equipment.
`
`22. We agree with IBM that, in general, two sets of standards should not apply to a single
`piece of equipment. In fact, the definition of a computing device in § 15.4(n) specifically
`excludes digital electronics included in ISM equipment. In other words, ISM equipment
`that utilizes digital electronics is governed only by the Part 18 rules. In the case of CPDs,
`what is unusual is that it is clearly a piece of computer equipment which only incidentally
`generates and uses RF energy to ionize a gas. We do not view CPDs as falling under the
`definition of ISM equipment because it is not the fundamental purpose of such equipment
`to generate and use RF energy for ISM applications. Accordingly, CPDs are subject only
`to the rules for computer equipment in Part 15, Subpart J. We believe that in most cases
`the rules are clear as to whether Parts 15 or 18 apply to a piece of equipment. If further
`guidance is needed, inquiries should be directed to the Chief Scientist.( 26 )
`
`23. In response to DSG's requests, we are adding a new § 18.309 to indicate the frequency
`range over which the measurements of field strength and conducted voltage levels must be
`recorded to verify compliance with the rules. In our proposal we only specified the
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`50 FR 36061
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`frequency range in the methods of measurements. This addition will provide the public
`with a better insight on the extent of the emission limits. See Appendix B, § 18.309.
`
`Methods of Measurements
`
`24. In the Notice we proposed to consolidate the methods of measurements for ISM equipment
`and to issue them separately from the Rules in a document entitled MP-5, "Methods of
`Measurements for ISM Equipment". It is less costly for the Commission to publish the
`methods of measurements separately from the rest of the rules. It is also advantageous to
`manufacturers and test facilities that are only concerned with measurement procedures for
`certain types of products. MP-5 is not a mandatory test procedure, but is basically a
`guideline and a summary of the methods used at the FCC laboratory for evaluating the
`radiated radio noise from ISM equipment. MP-5 supersedes FCC Bulletins OCE 39
`(dealing with medical diathermy equipment), OCE 20 (discussing microwave ovens), and
`Test Procedure No. 2 (regarding ultrasonic equipment). Comments on the proposed MP-5
`are positive but requests for clarification or changes have been made in the area of test
`sites, measuring
`instrumentation, attenuation
`law
`factors, and
`line conducted
`measurements.
`
`25. Consumer products or certified equipment, as described in MP-5, should be tested on an
`open field site or at a location which yields comparable results. Classical ISM or verified
`equipment can be tested at any location. It was not our intent in the proposal, as AFTRCC,
`GE, IBM, and others interpreted, to preclude testing equipment on-site, i.e., testing a given
`piece of equipment at its actual place of installation.( 27 ) Sections 2.1 and 2.1.1 of MP-5
`indicate that this is permitted. However, it appears that some clarification is needed as to
`what the criteria will be for accepting data taken at a manufacturer's plant or at a location
`other than an open field. That is, in what situations will the measurements be considered
`sufficiently representative of how the equipment will perform at any installation, that the
`marketing of that equipment may be based on that single set of measurements? If the
`individual installation has unique shielding, we shall consider the test results as being
`representative of that case only. For example, in situations where the equipment is located
`in a building with metal walls or deep inside a building, with measurements taken outside
`that building, cannot be considered representative of how the equipment will perform at
`any other installation; the same degree of shielding may not be present. Some judgment
`must be exercised in choosing a location other than an open field, as has been done in the
`past, if only a single set of measurements is to be performed. If due to the location of the
`equipment in a large city, or for some other reason, measurements as outlined in MP-5 are
`impractical because large buildings or other objects are in the path where measurements
`should be taken, every effort should be made to obtain necessary measurements at the
`nearest clear location(s).
`
`26. Modifications to the minimum 6 dB bandwidth of the measuring instrumentation we
`proposed to use for frequencies below 30 MHz have been requested by several parties.( 28
`) The consensus is that from 150 kHz to 30 MHz the 6 dB bandwidth of the measuring
`instrumentation should be specified to be at least 9 kHz, and below 150 kHz at least 200
`Hz. Commenters believe that the Commission's proposal of 3 kHz minimum bandwidth
`below 450 kHz might contradict its requirement to use a radio noise meter or spectrum
`analyzer which conforms with ANSI (American National Standards Institute) C63.2-1980
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`standards. We find no apparent reason for not applying the ANSI C63.2-1980 standards to
`MP-5 and modify § 2.2.2 accordingly. This will help exporting manufacturers to perform
`only one set of measurements for verification of compliance with FCC rules and other
`countries' regulatons.
`
`27. In response to questions raised by SMC, we specify that the measurements need not always
`be undertaken at the distance at which the emission limits are applied. Due to the nature
`and the configuration of most ISM equipment, testing may be made at closer distances,
`especially for equipment for which the limits are specified at distances greater than 30
`meters; a sufficient number of measurements should be taken to plot a representative polar
`radiation pattern and to assure the correct determination of the major lobes. This should
`enable parties undertaking the measurements to record more accurately the attenuation
`factors applicable to a particular equipment. As an alternative, measurements may be made
`at a fixed closer distance, provided the field strength limits are readjusted using an
`attenuation law factor of 1/d (where d is the distance measured in appropriate units).
`
`28. Commenters note that the proposed MP-5 only deals with radiated radio noise and suggest
`that the power line conducted radio noise measurements for ISM equipment be made in
`accordance with MP-4, "FCC Methods of Radio Noise Emissions from Computing
`Devices", and/or ANSI C63.4-1981. We find merit in such a request especially since the
`tests undertaken by the FCC laboratory are similar to what is stated in MP-4. Conducted
`measurements are usually performed with the aid of a line impedance stabilization network
`(LISN).( 29 ) The use of a LISN assures repeatable measurements by stabilizing the
`impedance between the device under test and the power source. The limits for most ISM
`equipment were established using a 5 uH/50 ohm LISN. Some commenters believe that the
`use of a 50 mu H/50 ohm LISN will be more appropriate especially below 2 MHz.
`However, we feel that the use of a LISN other than the one specified will cause inaccurate
`readings. We will, therefore, specify in MP-5 that measurements are to be made using the
`LISN with which the conducted voltage limits have been specified. We have accepted, in
`the past, that measurements be made with LISN's other than the one indicated in the
`methods of measurements, but only because the required LISN was not always available
`commercially. Most test facilities are now equipped with both 5 mu H and 50 mu H
`LISN's. However, parties encountering difficulty in procuring the required LISN should
`contact the FCC laboratory.
`
`29. Additional information on interconnecting cables, accessories, and applicators has been
`included in MP-5. Also, to allow more flexibility, we shall accept radiated radio noise
`measurements above 1 GHz made with a broadband linearly polarized horn antenna or any
`other comparable antenna.( 30 ) We wish to emphasize that MP-5 is a recommended
`procedure and that alternatives are permitted by the Commission as long as they are
`justifiable. We recommend that parties who intend to use alternate procedures contact the
`FCC laboratory