WPC 2BJ|{ I. A. 1. a.(1)(a) i) a) 1. 1. 1. a.(1)(a) i) a) X-#XP\  P6Q+XP# X   )K X-w  #XP\  P6Q+XP#Federal Communications Commission`(# FCC 96407 ă  yxdddy )+2 Before the w Federal Communications Commission  X-Washington, D.C. 20554 ă x` `  hh@hpp   In the Matter ofR) R) Amendment of Part 87 to Permit the R)  X_-Use of 112118 MHz for Differential Global R)hppWT Docket No. 96211  XH-Positioning System (GPS) Correction Data R)hppRM8607, 8687 and the Use of Handheld TransmittersR) on Frequencies in the Aeronautical R) Enroute ServiceR) R)  X -andR)h R) Amendment of Part 17 ConcerningR) Construction, Marking, and Lighting ofR) Antenna StructuresR) T  s!E   X4-l  NOTICE OF PROPOSED RULE MAKING TP  X-X` hp x (#%'0*,.8135@8:horizontally. This accuracy can be improved to better than one meter, however, by using a  xtechnique called "differential GPS." Differential GPS employs two GPS units or receivers. In  X- xaddition to the mobile GPS receiver (e.g., the receiver on an aircraft), another receiver (stationary  X}- x>receiver) is placed at a location where the precise coordinates are already known (reference  xpoint). The stationary receiver calculates the difference between the reference point and the  xjpredicted location using GPS data. The difference between the two locations is the error in the  xGPS signal. Error correction data can then be transmitted to a mobile GPS unit to increase the accuracy of the position information shown by that unit.   x5. The FAA requests that we amend Part 87 of our rules to allow entities participating  xLin its SCATI landing and approach system to use unassigned VOR frequencies in the 112118  xMHz band to transmit error correction data obtained using differential GPS to units aboard  X- xaircraft.D } yO'-ԍxFAA Petition at 1. D Allowing Part 87 aeronautical ground stations at airports to use VOR frequencies in  xthis manner would increase navigation accuracy and thereby increase safety in aircraft landings  x?and approaches. By limiting such use to unassigned VOR frequencies, we eliminate the  x/possibility of interference with VOR operations. Further, the Commission has granted nine  XR- xxdevelopmental licenses for such systems xRX} yO[-  ԍxThe nine systems are Interstate Electronics Corp., (landing area not listed), Anaheim, CA, granted 6/11/96;  xIntersate Electronics Corp., Mojave Airport, Mojave, AZ, granted 6/11/96; Continental Airlines Inc., Newark  xInternational Airport, Newark, NJ, granted 6/05/96; Metropolitan Airports Commission, Minneapolis-St Paul  x International Airport, Minneapolis, MN, granted 4/04/96; Aeronautical Radio Inc., Alliance Fort Worth Airport, Fort  x+ Worth, TX, granted 9/15/95; Honeywell Inc., Rochester Airport, Rochester, MN, granted 6/30/95; State of Wisconsin,  xWittman Regional Airport, Oshkosh, WI, granted 10/28/93; Aeronautical Radio Inc., (landing area not listed), Newark, NJ, granted 11/15/93; Aeronautical Radio Inc., (landing area not listed), Houston, TX, granted 11/15/93. and has received no complaints of harmful interference  x<to VOR stations. Thus, we do not believe that allowing the operations proposed by the FAA will  xincrease the incidence of harmful interference in the 112118 MHz band. As a result, we propose  xto allow aeronautical ground stations to use unassigned VOR frequencies in the 112118 MHz"  ,-(-(ZZ="  xband to transmit differential GPS data. In order to expedite assignment of these frequencies, we  xalso propose to require proof from the applicants that frequency assignments were coordinated with the FAA prior to seeking a Commission authorization.   x6. Additionally, to accommodate the technical parameters of these proposed new ground  X- xstation transmitters, we propose to amend 47 C.F.R.  87.137(a) to include "14KG7D"g X} yO-  ԍxThe emission designator "14KG7D" refers to a data or telemetry transmission with a necessary bandwidth  xof 14 kHz that is phase-modulated and contains one or more channels of digital information together with one or more channels of analog information. See 47 C.F.R.  2.201.g as an  x[authorized type of emission. We also propose to amend 47 C.F.R.  87.171 to designate "RLP"  xas the symbol for the class of station for differential GPS ground stations. We invite comments  x=concerning these proposals as well as any alternatives thereto. We also seek comment on the following issues:   |x(a) Should an applicant for a differential GPS ground station be required to notify the  xyapplicable airport authority or aviation service organizations prior to receiving an authorization  xfor operation at a particular airport? Should the Commission prohibit multiple licensees from  xoperating at a single airport or, in the alternative, limit the number of licensees operating at a single airport?   /x(b) What measures may be taken to expedite coordination procedures between applicants,  xthe FAA, and the Commission concerning the assignment of a frequency and time slot for differential GPS ground stations?   x(c) The proposed rules would require differential GPS transmitters to be type accepted  x[in accordance with the proposed technical criteria set forth in Appendix B (47 C.F.R.  87.131,  x87.133(a)(5), 87.137(a), 87.139(j), 87.145, and 87.147(d)), in lieu of the specifications contained  xin RTCA Document No. DO217. We believe that this flexible approach promotes technological  X- xinnovations in differential GPS equipment consistent with the National Airspace System (e.g.,  xchanges in coding methodology or data timing structure) without requiring the Commission's  xrules to be amended to incorporate changes unrelated to radiofrequency interference. Under our  X~- xpresent treatment of transmitters operating in the 108137 MHz band,T~} {O-ԍxSee 47 C.F.R.  87.147(d).T the FAA is given a 21 x>day period to object to any application for type acceptance that would adversely affect the  xperformance of the National Airspace System. Are these proposed requirements sufficient to  x\ensure proper operation of differential GPS ground station transmitters? If not, what would constitute sufficient requirements?  X-x B. Use of HandHeld Transmitters on Aeronautical Enroute Service Frequencies   x7. On February 2, 1995, ARINC filed a petition to permit use of handheld radios on  xfrequencies allocated to the Aeronautical Enroute Service so that flight crews can communicate"!z,-(-(ZZ "  X- xdirectly with ground service personnel while the aircraft is on the ground.`} {Oy-ԍxSee supra note ARINC PETITION2.` According to  x\ARINC, today's commercial aircraft require direct wireless contact between flight crews and  xground service personnel in lieu of the present means of communications through a dispatch  xcenter or via a tethered communication line physically connecting ground personnel with an  xNaircraft. ARINC contends that this need for a wireless radio link arises from recent FAA  x<regulations concerning deicing aircraft prior to takeoff, increased traffic on airport runways, and  Xv- xZthe safety hazards associated with tethered connections.KvZ} yO -ԍxARINC Petition at 2.K ARINC argues that the lack of a direct  xwireless communications capability compromises safety of airport personnel and often results in  XH- xxunnecessary delays in persons aboard aircraft being able to obtain service or supplies.EH} yO -ԍxARINC Petition at 2.E ARINC's  X1- xpetition was placed on Public Notice.j1z} {O\-ԍxSee FCC Public Notice No. 2059 (February 28, 1995).j No comments were received in response to the Public Notice.  X -  x8. Aeronautical Enroute stations provide for operational control (e.g., flight management)  xof aircraft along domestic or international air routes. Operational control communications are  xdefined as communications relating to the safe, efficient and economical operation of the  X - xaircraft.N } {Of-ԍxSee 47 CFR  87.261.N Examples of operational control communications are communications concerning fuel,  xkweather, aircraft position and performance and requests for essential services and supplies.  xCurrently, the rules do not permit direct communications between the flight crews and ground  xservice personnel via handheld radios. Instead, the flight crews and ground service personnel  XM- xmust communicate through the aeronautical enroute ground station (base station), or a wired connection to the plane on the ground.   Nx9. Because of the concerns presented by ARINC, we tentatively conclude that allowing  xhandheld radio operation on aeronautical enroute frequencies will increase airport safety, promote  xthe more efficient use of aviation spectrum, and reduce waiting times for aircraft to obtain  x[essential services and supplies. Therefore, we propose to allow the use of handheld radios at  xairports for communications by ground service personnel with aircraft or the associated enroute  x=station. In order to reduce administrative burdens on both the public and the Commission, we  xfurther propose to permit such mobile units to operate under the same authorization and call sign  xMas the associated aeronautical enroute station. This approach would eliminate the need for  xaviation service organizations to submit forms and fees to the Commission, while minimizing  xadministrative burdens on the Commission. We seek comment on our proposal and tentative conclusion. We also seek comment on the following issues: " ,-(-(ZZ"Ԍ  x(a) Should the present technical specifications and type acceptance requirements governing  x|the use of aircraft hand-held radio equipment (47 C.F.R. 87.131, 87.133(a)(5), 87.137(a),  x?87.139(a), 87.141(a), 87.145(b), and 87.147(d)) be applied to hand-held radio operation on aeronautical enroute frequencies?   x(b) We do not propose to limit the number of handheld transmitters authorized under  xan aeronautical enroute license. What would be the advantages and disadvantages of limiting the  xknumber of handheld transmitters authorized at a single airport? If the number of handheld  x[transmitters was limited, what would be a reasonable maximum number? Is there a need for the Commission to keep track of the exact number of handhelds being used at each airport?   !x(c) ARINC's petition requests that handheld transmitters, which are commonly battery  xoperated, low power, and of limited range, be permitted to operate on aeronautical enroute  xMfrequencies. Should the Commission allow such handheld transmitters to be connected to external power sources or to high gain antennas that increase their range?  X- C. Revised FAA Advisory Circulars  Xb-  Nx 10. In the Report and Order in WT Docket No. 955, we incorporated, by reference, two  XM- xLFAA Advisory Circulars, "Obstruction Marking and Lighting" (AC 70/74601H), August 1991,  X6- xas amended by Change 2, July 15, 1992, and "Specification for Obstruction Lighting Equipment"  X- x(AC 150/534543D), July 1988, in Part 17 of our rules.} {O-  ԍxSee Streamlining the Commission's Antenna Structure Clearance Procedure and Revision of Part 17 of the  {Ob- xCommission's Rules Concerning Construction, Marking, and Lighting of Antenna Structures, Report and Order, WT  x-Docket No. 955, 11 FCC Rcd 4272 (1996). FAA Advisory Circulars are available upon request, free of charge,  xfrom Department of Transportation, Utilization and Storage Section (Publications), M443.2, 400 7th Street SW, Washington, DC 20591, telephone (202) 3660039 or (202) 3660451. The Commission chose this approach  xLin order to unify federal guidelines concerning the painting and lighting of antenna structures.  xIn doing so, we stated that if the FAA makes substantive amendments to either of these Advisory  xCirculars, the Commission would initiate a public proceeding prior to updating Part 17 of our  X- xrules.E|} {O-ԍxId., para. 48.E In this connection, the FAA has recently made substantive amendments to both Advisory  xCirculars. Accordingly, we propose to incorporate the revised FAA Advisory Circulars, AC  X- x70/7460-1J (January 1, 1996) and AC 150/5345-43E (October 19, 1995), in Part 17 of our rules.} yOT!-  >ԍxThe Advisory Circulars (which are attached as Appendix C) are available in the Commission's docket file  xin this proceeding or may be purchased from the Commission's copy contractor, International Transcription Service,  xInc., 2100 M Street, Suite 140, Washington, D.C. 20037, telephone (202) 8573800. The Commission must obtain  xauthorization from the Director of the Federal Register prior to incorporating by reference the two FAA Advisory  {Ot$-Circulars in Part 17 of our rules. See 1 C.F.R. Part 51.  x,We propose not to require Antenna structure owners that were previously assigned painting and/or  xlighting requirements by the Commission to update their structures in accordance with the revised  xAdvisory Circulars unless specifically recommended by the FAA. We seek comment on this"P ,-(-(ZZ" proposal.  X- III. CONCLUSION ĐTP   "x 11. Accordingly, we propose to amend Part 87 of our rules to permit: (1) licensing of  x the frequencies 112118 MHz for aeronautical ground stations transmitting differential GPS  xcorrections; and (2) the use of frequencies in the Aeronautical Enroute Service by handheld  xZradios under certain circumstances. We also propose to amend Part 17 of our rules to incorporate  xby reference two recently revised FAA advisory circulars concerning antenna structure painting  xand lighting. The proposed actions will increase the safety and efficiency of aircraft navigation  xand movement of aircraft in and around airports. Further, adoption of these proposals would  xpromote the use of new radio technologies beneficial to aircraft without allocating additional spectrum. s!E   X -u IV. PROCEDURAL MATTERS ĐTP  X< A. Ex Parte Rules NonRestricted Proceeding.  Xc-  x 12. This is a nonrestricted notice and comment rule making proceeding. Ex Parte  xpresentations are permitted, except during the Sunshine Agenda period, provided they are  X7- xdisclosed as provided in Commission rules. See generally 47 C.F.R.  1.1202, 1.1203, and 1.1206(a).  X- B. Initial Regulatory Flexibility Analysis x 13. An Initial Regulatory Flexibility Analysis is contained in Appendix A.  X- C. Comment Dates   2x 14. Pursuant to applicable procedures set forth in Sections 1.415 and 1.419 of the  xCommission's Rules, 47. C.F.R.  1.415 and 1.419, interested parties may file comments on or  x\before January 15, 1997, and reply comments on or before January 30, 1997. To file formally  xin this proceeding, you must file an original and four copies of all comments, reply comments,  xLand supporting comments. If you want each Commissioner to receive a personal copy of your  xcomments, you must file an original plus nine copies. You must send comments and reply  xcomments to Office of the Secretary, Federal Communications Commission, Washington, DC  x20554. You may also file informal comments by electronics mail. You should address informal  x>comments to mayday@fcc.gov. You must put the docket number of the proceeding on the  xsubject line ("WT Docket No. 96211). You must also include your full name and Postal Service  xjmailing address in the text of the message. Formal and informal comments and reply comments  x\will be available for public inspection during regular business hours in the F.C.C. Reference  xCenter of the Federal Communications Commission, Room 239, 1919 M Street, N.W., Washington, DC 20554. "&',-(-(ZZ%"Ԍ  ?x15. For further information, contact Mr. Jim Shaffer, Private Wireless Division, Wireless Telecommunications Bureau, at (202) 4180680 or at mayday@fcc.gov.  X-  x16. Authority for issuance of this Notice of Proposed Rule Making is contained in  x\Sections 4(i) and 303(r) of the Communications Act of 1934, as amended, 47 U.S.C.  154(i) and 303(r). x` `  hh@FEDERAL COMMUNICATIONS COMMISSION x` `  hh@William F. Caton x` `  hh@Acting Secretary" ,-(-(ZZm "  X-) APPENDIX A ĐTP  X-  INITIAL REGULATORY FLEXIBILITY ANALYSIS ĐTP  X-xAs required by Section 603 of the Regulatory Flexibility Act,D} yO-ԍx 5 U.S.C.  603.D the Commission has prepared an Initial Regulatory Flexibility Analysis (IRFA) of the expected significant  X_-economic impact on small entities by the policies and rules proposed in the Amendment of Part 87 to Permit the Use of 112118 MHz for Differential Global Positioning System (GPS) Correction Data and the Use of Handheld Transmitters on Frequencies in the Aeronautical Enroute Service, and Amendment of Part 17 Concerning Construction, Marking, and Lighting  X -of Antenna Structures. Written public comments are requested on the IRFA. Comments must be identified as responses to the IRFA and must be filed by the deadlines for comments on  X -the Notice of Proposed Rule Making, provided in paragraph 14 of the item.  X - I. Need for and Objectives of the Proposed Rule: The purpose of this Notice of Proposed  X-Rule Making is to determine whether it is in the public interest, convenience, and necessity to amend our rules to permit licensing of frequencies in the 112118 MHz band for aviation ground monitoring systems that are associated with the GPS; to permit under limited circumstances the use of frequencies in the aeronautical enroute service for hand held radios. These proposed actions should increase the safety and efficiency of aircraft navigation and movement of aircraft in and around airports. We also propose to incorporate by reference two recently revised FAA advisory circulars concerning antenna structure painting and lighting.  X- II. Legal Basis: Authority for issuance of this Notice of Proposed Rule Making is contained in Sections 4(i) and 303(r) of the Communications Act of 1934, as amended, 47 U.S.C.  154(i) and 303(r).  Xq- III. Description and Estimate of the Number of Small Entities to Which Rule Will  XZ-Apply: The proposed amendments will affect small businesses that use, manufacturer, design, import, or sell a GPS augmentation system operating in the 112118 MHz band. We tentatively conclude that these small businesses are classified in Communications Equipment, N.E.C., (Standard Identification Code 3669) as entities employing less than 750 employees as defined in 13 CFR 121.201. We invite comment on whether this is the correct definition to use. The size data provided by the SBA shows that 469 firms out of 498 firms in the communications equipment, nec classification have less than 750 employees but does not enable us to make a meaningful estimate of the number of potential GPS manufacturers which"! X,-(-(ZZ "  X-are small businesses.*X} yOy-  ԍxU.S. Small Business Administration 1992 Economic Census Industry and Enterprise Report, Table 1D, SIC  x0Code 3669, (Bureau of the Census data adapted by the Office of Advocacy of the U.S. Small Business Administration).* However, based on information from the U.S. GPS Industry Council we estimate that this would include approximately 110 small businesses that would be affected by this proposed rule change.  X- IV. Description of Projected reporting, recordkeeping, and other compliance  X-requirements: In order to facilitate operation of a GPS augmentation system operating in the 112118 MHz band, these proposed rules may have significant economic impact on a substantial number of small businesses. Prior to marketing a GPS augmentation system operating in the 112118 MHz band in the U.S., a manufacturer must have the unit type accepted by the Commission under the technical criteria set forth in the RTCA Document No.  X -DO217, Minimum Aviation System Performance Standards/Differential Global Navigation  X -Satellite System Instrument Approach System: Special Category I (SCATI), August 27, 1993. In order to have a unit type accepted, a small entity would have to test the radio equipment and provide clerical support to file the requisite FCC application forms. Both of these functions could be handled by a third party. We estimate that the initial cost to the manufacturer to meet this requirement, if done by a third party, is $900 to test the equipment and complete the filing information, and would require the electronic engineering professional skills. Additionally, there would be a $425 equipment authorization fee to file the application for type acceptance. These costs are one time costs to type accept the equipment and assure that interference to other radio users is minimized.  X!- V. Significant Alternatives to Proposed Rules Which Minimize Significant Economic  X -Impact on Small Entities and Accomplish Stated Objectives: The proposed rules would require differential GPS transmitters to be type accepted in accordance with the technical criteria set forth in Part 87 Subpart D of our rules, in lieu of the more exacting specifications contained in RTCA Document No. DO217. We believe that this flexible approach promotes technological innovations in differential GPS equipment so long as such equipment is compatible with the National Airspace System. Under our present treatment of transmitters operating in the 108137 MHz band, the FAA is given a 21day period to object to any application for type acceptance that would adversely affect the performance of the National Airspace System. We seek comments on whether these proposed requirements are sufficient to ensure proper operation of differential GPS ground station transmitters or, if not, what would constitute sufficient requirements. The proposed rules also seek to take measures to minimize burden and expedite coordination procedures between applicants, the FAA, and the Commission concerning the assignment of a frequency and time slot for differential GPS ground stations. In order to reduce administrative burdens on both the public and the Commission, we further propose to permit mobile units in the aeronautical enroute service to operate under the same authorization and call sign as the associated aeronautical enroute station. This approach would eliminate the need for aviation service organizations to submit"" ,-(-(ZZ!" forms and fees to the Commission. These decision benefits small entities and give them an opportunity to provide recommendations to further improve the impact and processes. x  X- VI. Federal rules which overlap, duplicate or conflict with these rules: None" ,-(-(ZZ"  X-) APPENDIX B ă xParts 17 and 87 of Chapter I of Title 47 of the Code of Federal Regulations are proposed to be amended as follows:  Xv-x PART 17 CONSTRUCTION, MARKING, AND LIGHTING OF ANTENNA  X_-STRUCTURES x1. The authority citation for Part 17 continues to read as follows:  X -x Authority: Secs. 4, 303, 48 Stat. 1066, 1082, as amended; 47 U.S.C. 154, 303.  X -Interpret or apply secs. 301, 303 48 Stat. 1081, 1085 as amended, 47 U.S.C. 301, 309. x2. Section 17.23 is revised to read as follows:  X-  17.23 Specifications for painting and lighting antenna structures. Unless otherwise specified by the Commission, each new or altered antenna structure to be registered on or after January 1, 1996, must conform to the FAA's painting and lighting recommendations set forth on the structure's FAA determination of "no hazard," as referenced in the following FAA Advisory Circulars: AC 70/74601J, "Obstruction Marking and Lighting," January 1, 1996, and AC 150/534543E, "Specification for Obstruction Lighting Equipment," October 19, 1995. These documents are incorporated by reference in accordance with 5 U.S.C. 552(a). The documents contain FAA recommendations for painting and lighting structures which pose a potential hazard to air navigation. For purposes of this part, the specifications, standards, and general requirements stated in these documents are mandatory. The Advisory Circulars listed above are available for inspection at the Commission Headquarters in Washington, DC, or may be obtained from Department of Transportation, Property Use and Storage Section, Subsequent Distribution Office, M483.6, Ardmore East Business Center, 3341 Q 75th Avenue, Landover, MD 20785, telephone (301) 3224961, facsimile (301) 3865394.  X -x PART 87 AVIATION SERVICES x1. The authority citation for Part 87 continues to read as follows:  X!-x Authority: 48 Stat. 1066, 1082, as amended; 47 U.S.C. 154, 303, unless otherwise  X"-noted. Interpret or apply 48 Stat. 10641068, 10811105, as amended, 47 U.S.C. 151156,  X#-301609. x2. Section 87.131 is amended by adding to the end of the table, the class of station for Differential GPS to read as follows: "#' ,-(-(ZZ%"Ԍ X-x  87.131 Power and emissions.  X-Class of Station Frequency band/frequencyhAuthorized emission  Maximum power1 x6* * * * *  X-Aircraft earth` `  UHFhh@hG1D,G1E,G1W  60 watts.8 0  Xv-Differential GPS VHFhh@hG7Dpp  Various.2  X_-x` `  hh@hpp  xx 0  XH-1 The power is measured at the transmitter output terminals and the type of power is determined according to the emission designator as follows: (i) Mean power (pY) for amplitude modulated emissions and transmitting both sidebands using un modulated full carrier. (ii) Peak envelope power (pX) of all emissions designators other than those referred to in paragraph (i) of this row.  X -2 Power and antenna height are restricted to the minimum necessary to achieve the required service. 6* * * * *  XK-8 Power may not exceed 60 watts per carrier. The maximum EIRP may not exceed 2000 watts per carrier. x3. Section 87.133 is amended by adding to the table in paragraph (a) in the (5) Band100 to 137 MHz: entry, the category of station Differential GPS to read as follows:  X-x  87.133 Frequency stability.  X-Frequency band (lower limit exclusive,upper limithTolerance1Tolerance2 inclusive), and categories of stations. 6* * * * * (5) Band100 to 137 MHz:  X - Aeronautical stationshh@h450pp  50 6* * * * *  X- Radionavigation stationshh@20hpp20  X - Differential GPS hh@hpp  2 6* * * * *  X"-x` `  hh@hpp  xx 0  X#-1  This tolerance is the maximum permitted until January 1, 1990, for transmitters installed before January 2, 1985, and used at the same installation. Tolerance is indicated in parts in  XQ%-106 unless shown as Hertz (Hz).  X:&-2  This tolerance is the maximum permitted after January 1, 1985, for new and replacement  X#'-transmitters after January 2, 1990. Tolerance is indicated in parts in 106 unless shown as"#' ,-(-(ZZ'" Hertz (Hz). 6* * * * *  X-4 The tolerance for transmitters type accepted between January 1, 1996, and January 1, 1974,  X-is 30 parts in 106. The tolerance for transmitters type accepted after January 1, 1974, and  X-stations using offset carrier techniques is 20 parts in 106. 6* * * * * x4. Section 87.137 is amended by adding to the table in paragraph (a) in its alphabetical order, the class of emission G7D to read as follows:  X -x  87.137 Types of emission. 6* * * * * Authorized bandwidth (kilohertz)  X- Class of emissionEmission@Below 50ppAbove 50  Frequency  Xy-x` `  designator@MHzhppMHz   deviation 6* * * * *  X- G7D....................14K0G7D pp 25 6* * * * * x5. Section 87.139 is amended by revising paragraph (a), and adding a new paragraph (j) to read as follows:  X|-x  87.139 Emission limitations. (a) Except of ELTs and when using single sideband (R3E, H3E, J3E), or frequency modulation (F9) or digital modulation (F9Y) for telemetry or telecommand in the frequency bands 14351535 MHz and 23102390 MHz or digital modulation (G7D) for differential GPS, the mean power of any emission must be attenuated below the mean power of the transmitter (pY) as follows: 6* * * * * (j) When using G7D for differential GPS in the 112118 MHz band, the amount of power during transmission under all operating conditions when measured over a 25 kHz bandwidth centered on either of the second adjacent channels shall not exceed 25 dBm and shall decrease 5 dB per octave until 52 dBm. "#',-(-(ZZ%&"Ԍx6. Section 87.171 is amended by adding in its alphabetical order the symbol and class of station for RLP to read as follows:  X-x  87.171 Class of station symbols. 6* * * * * xRLP Differential GPS 6* * * * * PPP x7. Section 87.173 is amended by revising the frequency table in paragraph (b) to add the listing 112118 MHz.  X -x  87.173 Frequencies x(b) * * *  XK-Frequency or frequency bandhhSubparthClass of station  Remarks 6* * * * *  X-112118 MHz..................hh Q@h RLP  Differential GPS  X-XxP(#6* * * * *pp  X- x8. Section 87.261 is amended by adding paragraph (e) to read as follows:  Xe-x  87.261 Scope of Service  XN-XxP(#6* * * * *pp x(e) Handheld units may be operated under an aeronautical enroute station authorization so long as the units are limited to use at an airport and are only used to communicate with aircraft on the ground or the associated aeronautical enroute station. Handheld units are further limited to operation on the VHF frequencies listed in 87.263(a)(1). x9. Section 87.475 is amended by adding paragraph (e) to read as follows:  X#-x  87.475 Frequencies. 6* * * * *  X#'-x(e) Frequencies available for differential GPS stations. Frequencies in the "#',-(-(ZZ%"Ԍ112118 MHz band may be assigned to Special Category I (SCATI) ground stations for differential GPS data links. x(1) The frequencies available are on 25 kHz centers with the lowest assignable frequency being centered at 112.000 MHz and the highest assignable frequency being centered at 117.950 MHz x(2) Applicants must obtain a frequency and time slot assignment from the FAA.