~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ THE LWCA.ORG PART 15 PAGE PRESENTS FCC RULES AND REGULATIONS, PART 15 ABRIDGED VERSION (Editing Notes: This version contains only those sections most relevant to home experimenters. If additional information is needed, refer to other files at this site. Where it may not be self-evident why a given section is inapplicable, some text is given to clarify the nature of the rule; then, four dots show that the material is truncated. Example: see Sec. 15.237.) While reasonable care has been taken in preparing this file, a number of typographical errors are probable. No legal advice is given or should be inferred. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CODE OF FEDERAL REGULATIONS 41 CFR Ch. 1 (10-1-93 Edition) TITLE 47, TELECOMMUNICATION PART 15-RADIO FREQUENCY DEVICES Subpart A-General Sec. 15.1 Scope of this part. 15.3 Definitions. 15.5 General conditions of operation. 15.7 Special temporary authority. 15.9 Prohibition against eavesdropping. 15.11 Cross reference. 15.13 Incidental radiators. 15.15 General technical requirements. 15.17 Susceptibility to interference. 15.19 Labelling requirements. 15.21 Information to user. 15.23 Home-built devices. 15.25 Kits. 15.27 Special accessories. 15.29 Inspection by the Commission. 15.31 Measurement standards. 15.33 Frequency range of radiated measurements. 15.35 Measurement detector functions and bandwidths. 15.37 Transition provisions for compliance with the rules. Subpart B-Unintentional Radiators 15.101 Equipment authorization of unintentional radiators. 15.103 Exempted devices. 15.105 Information to the user. 15.107 Conducted limits. 15.109 Radiated emission limits. 15.111 Antenna power conduction limits for receivers. 15.113 Power line carrier systems. 15.115 TV interface devices, including cable system terminal devices. 15.117 TV broadcast receivers. 15.119 Closed caption decoder requirements for television receivers. 15.121 Scanning receivers and frequency converters designed or marketed for use with scanning receivers. Subpart C-lntentional Radiators 15.2Ol Equipment authorization requirement. 15.203 Antenna requirement. 15.205 Restricted bands of operation. 15.207 Conducted limits. 15.209 Radiated emission limits, general requirements. 15.211 Tunnel radio systems. 15.213 Cable locating equipment. 15.214 Cordless telephones. RADIATED EMISSION LIMITS, ADDITIONAL PROVISIONS 15.215 Additional provisions to the general radiated emission limitations. 15.217 Operation in the band 160-190 kHz. 15.219 Operation in the band 510-1705 kHz. 15.221 Operation in the band 525-1705kHz. 15.223 Operation in the band 1.705-10 MHz. 15.225 Operation within the band 13.553-13.567 MHz. 15.227 Operation within the band 26.96-27.28 MHz. 15.229 Operation within the band 40.66-40.70 MHz. 15.231 Periodic operation in the band 40.66-40.70 MHz and above 70 MHz. 15.233 Operation within the bands 46.60-46.98 MHz and 49.66-50.0 MHz. 15.235 Operation within the band 49.82-49.90 MHz. 15.237 Operation in the bands 72.0-73.0 MHz, 74.6-74.8 MHz and 75.2-76.0 MHz. 15.239 Operation in the band 88-108 MHz. 15.241 Operation in the band 174-216 MHz. 15.243 Operation in the band 890-940 MHz. 15.245 Operation within the bands 902-925 MHz, 2400-2483.5 MHz, 5785-5815 MHz, 10500-10550 MHz, and 24075-24175 MHz. 15.247 Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz. 15.249 Operatlon within the bands 902-928 MHz, 2400-2483.5 MHz, 5725-5875 MHz, and 24.0-24.25 GHz. 15.251 Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz. and 3.358-3.6 GHz. AUTHORITY: Sec. 4, 302, 303, 304, and 307 of the Communications Act of 1934, as amended. 47 U.S.C. sections 154, 302, 303, 304. and 307. Subpart A-General 15.1 Scope of this part. (a) This part sets out the regulations under which an intentional, uninten- tional, or incidental radiator may be operated without an individual license. It also contains the technical specifications, administrative requirements and other conditions relating to the marketing of part 15 devices. (b) The operation of an intentional or unintentional radiator that is not in accordance with the regulations in this part must be licensed pursuant to the provisions of section 301 of the Communications Act of 1934, as amended, un- less otherwise exempted from the licensing requirements elsewhere in this chapter. (c) Unless specifically exempted, the operation or marketing of an inten- tional or unintentional radiator that is not in compliance with the administra- tive and technical provisions in this part, including prior Commission au- thorization or verification, as appropriate, is prohibited under section 302 of the Communications Act of 1934, as amended, and subpart I of part 2 of this chapter. The equipment authorization and verification procedures are de- tailed in subpart J of part 2 of this chapter. 15.3 Definitions. (m) Harmful interference. Any emission, radiation or induction that en- dangers the functioning of a radio navigation service or of other safety serv- ices or seriously degrades, obstructs or repeatedly interrupts a radiocommunications service operating in accordance with this chapter. (n) Incidental radiator. A device that generates radio frequency energy dur- ing the course of its operation although the device is not intentionally designed to generate or emit radio frequency energy. Examples of incidental radiators are dc motors, mechanical light switches, etc. (o) Intentional radiator. A device that intentionally generates and emits radio frequency energy by radiation or induction. (t) Power line carrier systems. An unintentional radiator employed as a car- rier current system used by an electric power utility entity on transmission lines for protective relaying, telemetry, etc. for general supervision of the power system. The system operates by the transmission of radio frequency en- ergy by conduction over the electric power transmission lines of the system. The system does not include those electric lines which connect the distribu- tion substation to the customer or house wiring. (u) Radio frequency (RF) energy. Electromagnetic energy at any frequency in the radio spectrum between 9 hHz and 3,000,000 MHz. (z) Unintentional radiator. A device that intentionally generates radio fre- quency energy for use within the device, or that sends radio frequency sig- nals by conduction to associated equipment via connecting wiring, but which is not intended to emit RF energy by radiation or induction. 15.5 General conditions of operation. (a) Persons operating intentional or unintentional radiators shall not be deemed to have any vested or recognizable right to continued use of any given frequency by virtue of prior registration or certification of equipment.... (b) Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused and that interference must be accepted that may be caused by the operation of an auth- orized radio station, by another intentional or unintentional radiator, by in- dustrial, scientific and medical (ISM) equipment, or by an incidental radi- ator. (c) The operator of a radio frequency device shall be required to cease operating the device upon notification by a Commission representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful inter- ference has been corrected. (d) Intentional radiators that produce Class B emissions (damped wave) are prohibited. 15.8 Prohibition against eavesdropping. Except for the operations of law enforcement officers conducted under lawful authority, no person shall use, either directly or indirectly, a device operated pursuant to the provisions of this part for the purpose of overhearing or recording the private conversations of others unless such use is authorized by all of the parties engaging in the conversation. 15.15 General technical requirements. (a) An intentional or unintentional radiator shall be constructed in accord- ance with good engineering design and manufacturing practice. Emanations from the device shall be suppressed as much as practicable, but in no case shall the emanations exceed the levels specified in these rules. (b) An intentional or unintentional radiator must be constructed such that the adjustments of any control that is readily accessible by or intended to be accessible to the user will not cause operation of the device in violation of the regulations. (c) Parties responsible for equipment compliance should note that the limits specified in this part will not prevent harmful interference under all cir- cumstances. Since the operators of part 15 devices are required to cease op- eration should harmful interference occur to authorized users of the radio frequency spectrum, the parties responsible for equipment compliance are encouraged to employ the minimum field strength necessary for commu- nications, to provide greater attenuation of unwanted emissions than re- quired by these regulations, and to advise the user as to how to resolve harmful interference problems (for example, see 15.105(b)). 15.17 Susceptibility to interference. (a) Parties responsible for equipment compliance are advised to consider the proximity and the high power of non-Government licensed radio stations, such as broadcast, amateur and land mobile stations, and of U.S. Govern- ment radio stations when choosing operating frequencies during the design of their equipment so as to reduce the susceptibility for receiving harmful in- terference. Information on non-Government use of the spectrum can be ob- tained by consulting the Table of Frequency Allocations in Sec. 2.106 of this chapter. (b) Information on U.S. Government operations can be obtained by contact- ing: Director, Spectrum Plans and Policy, National Telecommunications and Information Administration, Department of Commerce, Room 4096, Wash- ington, DC 20230. 15.19 Labelling requirements. (a) In addition to the requirements in part 2 of this chapter, a device sub- ject to certification, notification, or verification shall be labelled as follows: . . . . (3) All other devices shall bear the following statement in a conspicuous location on the device: "This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any lnterference re- ceived, including interference that may cause undesired operation." (b) Where a device is constructed in two or more sections connected by wires and marketed together, the statement specified in this section is required to be affixed only to the main control unit. (c) When the device is so small or for such use that it is not practicable to place the statement specified in this section on it, the information required by these paragraphs shall be placed in a prominent location in the instruction manual or pamphlet supplied to the user or, alternatively, shall be placed on the container in which the device is marketed. However, the FCC identifier or the unique identifier, as appropriate, must be displayed on the device. 15.23 Home-built devices. (a) Equipment authorization is not required for devices that are not mar- keted, are not constructed from a bit, and are built in quantities of five or less for personal use. (b) It is recognized that the individual builder of home-built equipment may not possess the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to em- ploy good engineering practices to meet the specified technical standards to the greatest extent practicable. The provisions of Sec. 15.5 apply to this equipment. 15.29 Inspection by the Commission. (a) Any equipment or device subject to the provisions of this part, together with any certificate, notice of registration or any technical data required to be bept on file by the operator, supplier or party responsible for compli- ance of the device shall be made available for inspection by a Commission representative upon reasonable request. (b) The owner or operator of a radio frequency device subject to this part shall promptly furnish to the Commission or its representative such informa- tion as may be requested concerning the operation of the radio frequency device. (c) The party responsible for the compliance of any device subject to this part shall promptly furnish to the Commission or its representatives such information as may be requested concerning the operation of the device, in- cluding a copy of any measurements made for obtaining an equipment au- thorization or demonstrating compliance with the regulations. (d) The Commission, from time to time, may request the party respon- sible for compliance, including an importer, to submit to the FCC Labora- tory in Columbia, Maryland, various equipment to determine that the equip- ment continues to comply with the applicable standards. Shipping costs to the Commission's Laboratory and return shall be borne by the responsible party. Testing by the Commission will be performed using the measurement procedure(s) that was in effect at the time the equipment was authorized or verified. (e) For intentional radiators, measurements of the variation of the input power or the radiated signal level of the fundamental frequency component of the emission, as appropriate, shall be performed with the supply voltage varied between 85% and 115% of the nominal rated supply voltage. For bat- tery operated eguipment, the equipment tests shall be performed using a new battery. (g) Equipment under test shall be adjusted, using those controls that are readily accessible to or are intended to be accessible to the consumer, in such a manner as to maximixe the level of the emissions.... (h) For a composite system that incorporates devices contained either in a single enclosure or in separate enclosures connected by wire or cable, test- ing for compliance with the standards in this part shall be performed with all of the devices in the system functioning. If an intentional radiator incor- porates more than one antenna or other radiating source and these radi- ating sources are designed to emit at the same time, measurements of con- ducted and radiated emissions shall be performed with all radiating sources that are to be employed emitting.... (i) If the device under test provides for the connection of external acces- sories, including external electrical input signals. the device shall be tested with the accessories attached.... (k) A composite system is a system that incorporates different devices con- tained either in a single enclosure or in separate enclosures connected by wire or cable. If the individual devices in a composite system are subject to dif- ferent technical standards, each such device must comply with its specific standards. In no event may the measured emissions of the composite system exceed the highest level permitted for an individual component... (1) Measurements of radio frequency emissions conducted to the public util- ity power lines shall be performed using a 50 ohm/50 uH line-impedance stabilization network (LISN). 15.33 Frequency range of radiated measurements. (a) For an intentional radiator, the spectrum shall be investigated from the lowest radio frequency signal generated in the device, without going below 9 hHz, up to at least the tenth harmonic of the highest fundamental frequency or to 40 GHz, whichever is lower. If the intentional radiator con- tains a digital device...the frequency range shall be investigated up to the higher of the tenth harmonic of the highest fundamental frequency designed to be emitted by the intentional radiator or the upper frequency of the measure- ment range applicable to the digital device, as shown in paragraph (b)(l) of this section. Subpart C-lntentional Radiators 15.205 Restricted bands of operation. (a) Except as shown in paragraph (d) of this section, only spurious emissions are permitted in any of the frequency bands listed below: ============================================= MHz MHz 0.090-0.110 16.42-(16.)423 0.490-0.505 * 16.69475-16.69525 2.1735-2.1905 16.80425-16.80475 4.125-4.128 25.5-25.67 4.17725-4.17775 37.5-38.25 4.20725-4.20775 73-74.6 6.215-6.218 74.8-75.2 6.26775-6.26825 108-121.94 6.31175-6.31225 123-138 8.291-8.294 149.9-150.05 8.362-8.366 156.52475-156.52525 8.37625-8.38675 156.7-156.9 8.41425-8.41475 162.0125-167.17 12.29-12.293 167.72-173.2 12.51975-12.52025 240-285 12.57675-12.57725 322-335.4 ---------------------------------------------- MHz GHz 399.9-410 4.5-5.25 608-614 5.35-5.40 960-1240 7.25-7.75 1300-1427 8.025-8.5 1435-1626.5 9.0-9.2 1645.5-1646.5 9.3-9.5 1660-1710 10.6-12.7 1718.8-l722.2 13.25-13.4 2200-2300 14.47-14.5 2310-2390 15.35-16.2 2483.5-2500 17.7-21.4 2655-2900 22.01-23.12 3260-3267 23.6-24.0 3332-3339 31.2-31.8 3345.8-3358 36.43-36.5 3600-4400 ** --------------------------------------------- *Until February 1, 1999 this restricted band shall be 0.490-0.510 MHz. **Above 38.6 GHz. ============================================= (b) Except as provided in paragraphs (d) and (e) of this section, the field strength of emissions appearing within these freguency bands shall not exceed the limits shown in 15.209. 15.207 Conducted limits. (a) For an intentional radiator which is designed to be connected to the pub- lic utility (AC) power line, the radio frequency voltage that is conducted back onto the AC power line on any frequency or frequencies within the band 450 kHz to 30 MHz shall not exceed 250 microvolts. Compliance with this provision shall be based on the measurement of the radio frequency voltage between each power line and ground at the power terminals. (d) Measurements to demonstrate compliance with the conducted limits are not required for devices which only employ battery power for operation and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. Devices that include, or make provision for, the use of battery chargers which permit operating while charging, AC adaptors or battery eliminators or that connect to the AC power lines indirectly, obtaining their power through another device which is con- nected to the AC power lines, shall be tested to demonstrate compliance with the conducted limits. 15.209 Radiated emission limits; general requirements. (a) Except as provided elsewhere in this subpart, the emissions from an in- tentional radiator shall not exceed the field strength levels specified in the following table: ============================================================= Field strength Measurement Frequency (MHz) (microvolts/meter) distance (meters) ------------------------------------------------------------- 0.009---0.490 ........ 2400/F(kHz) 300 0.490-1.705 .......... 24000/F(kHz) 30 1.705-30.0 ........... 30 30 30-88 ................ 100 ** 3 88-216 ............... 150 ** 3 216-960 .............. 200 ** 3 Above 960 ........... 500 3 ------------------------------------------------------------- ** Except as provided in paragraph (g), fundamental emis- sions from intentional radiators operatlng under this Section shall not be located in the frequency bands 54-72 MHz, 76- 88 MHz, 174-216 MHz or 470-806 MHz. However, operation within these frequency bands is permitted under other sec- tions of this part, e.g.. 15131 and 15.241. ============================================================= (b) In the emission table above, the tighter limit applies at band edges. (c) The level of any unwanted emissions from an intentional radiator op- erating under these general provisions shall not exceed the level of the fun- damental emission. For intentional radiators which operate under the provi- ions of other sections within this part and which are required to reduce their unwanted emissions to the limits specified in this table, the limits in this table are based on the frequency of the unwanted emission and not the fun- damental frequency. However, the level of any unwanted emissions shall not exceed the level of the fundamental frequency. (d) The emission limits shown in the above table are based on measurements employing a CISPR quasi-peak detector except for the frequency bands 9-90 kHz, 110-490 kHz and above 1000 MHz. Radiated emission limits in these three bands are based on measurements employing an average detector. (f) In accordance with 15.33(a), in some cases the emissions from an in- tentional radiator must be measured to beyond the tenth harmonic of the high- est fundamental frequency designed to be emitted by the intentional radiator because of the incorporation of a digital device. If measurements above the tenth harmonic are so required, the radiated emissions above the tenth har- monic shall comply with the general radiated emission limits applicable to the incorporated digital device, as shown in 15.109 and as based on the frequency of the emission being measured, or, except for emissions con- tained in the restriceed frequency bands shown in 15.205, the limit on spurious emissions specified for the intentional radiator, whichever is the higher limit. Emissions which must be measured above the tenth harmonic of the highest fundamental frequency designed to be emitted by the intentional radiator and which fall within the restricted bands shall comply with the general radiated emission limits in 15.109 that are applicable to the incor- porated digital device. RADIATED EMISSION LIMITS, ADDITIONAL PROVISIONS 15.215 Additional provisions to the general radiated emission limitations. (a) The regulations in 15.217 through 15.251 provide alternatives to the general radiated emission limits for intentional radiators operating in specified frequency bands. Unless otherwise stated, there are no restrictions as to the types of operation permitted under these sections. (b) In most cases, unwanted emissions outside of the frequency bands shown in these alternative provisions must be attenuated to the emission limits shown in 15.209. In no case shall the level of the unwanted emissions from an intentional radiator operating under these additional provisions ex- ceed the field strength of the fundamental emission. (d) Where the following sections specify limits on the bandwidth of the emissions, the bandwidth limits include the effects of frequency sweeping, frequency hopping, and other modulation techniques which may be em- ployed. 15.217 Operation in the band 160-190 kHz. (a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed one watt. (b) The total length of the transmission line, antenna, and ground lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification may be based on measure- ments at the intentional radiator's antenna output terminal unless the in- tentional radiator uses a permanently attached antenna, in which case com- pliance shall be demonstrated by measuring the radiated emissions. 15.218 Operation in the band 510-1705 kHz. (a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed 100 milliwatts. (b) The total length of the transmission line, antenna and ground lead (if used) shall not exceed 3 meters. (c) All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification may be based on measure- ments at the intentional radiator's antenna output terminal unless the in- tentional radiator uses a permanently attached antenna, in which case com- pliance shall be demonstrated by measuring the radiated emissions. 15.221 Operation in the band 525-1705 kHz. (a) Carrier current systems and transmitters employing a leaky co- axial cable as the radiating antenna . . . . 15.225 Operation within the band 13.553-13.567 MHz. (a) The field strength of any emissions within this band shall not exceed 10,000 microvolts/meter at 30 meters. (b) The field strength of any emissions appearing outside of this band shall not exceed the general radiated emission limits shown in 15.209. (c) The frequency tolerance of the carrier signal shall be maintained within +/- 0.01% of the operating frequency over a temperature variation of -20 degrees to +50 degrees C at normal supply voltage, and for a variation in the primary supply voltage from 85% to 115% of the rated supply voltage at a temperature of 20 degrees C. For battery operated equipment, the equip- ment tests shall be performed using a new battery. 15.227 Operation within the band 26.98-27.28 MHz. (a) The field strength of any emission within this band shall not exceed 10,000 microvolts/meter at 3 meters. The emission limit in this paragraph is based on measurement instrumentation employing an average detector. The provisions in 15.35 for limiting peak emissions apply. (b) The field strength of any emissions which appear outside of this band shall not exceed the general radiated emission limits in 15.209. 15.229 Operation within the band 40.66-40.70 MHz. (a) Unless operating pursuant to the provisions in 15.231, the field strength of any emissions within this band shall not exceed 1,000 microvolts/meter at 3 meters. (c) The field strength of any emissions appearing outside of this band shall not exceed the general radiated emission limits in 15.209. (d) The frequency tolerance of the carrier signal shall be maineained within +/- O.O1% of the operating frequency over a temperature variation of - 20 degrees to +50 degrees C at normal supply voltage, and for a variation in the primary supply voltage from 85% to 115% of the rated supply voltage at a temperature of 20 degrees C. For battery operated equipment, the equip- ment tests shall be performed using a new battery. 15.231 Periodic operation in the band 40.66-40.70 MHz and above 70 MHz. (a) The provisions of this section are restricted to....the transmission of a control signal such as those used with alarm systems, door openers, remote switches, etc. Radio control of toys is not permitted. Continuous trans- missions, such as voice or video, and data transmissions are not permitted. . . . . 15.233 Operation within the bands 48.80-48.98 MHz and 49.66-50.0 MHz. (a) The provisions shown in this section are restricted to cordless tele- phones. . . . 15.235 Operation within the band 49.82-49.80 MHz. (a) The field strength of any emission within this band shall not exceed 10,000 microvolts/meter at 3 meters. The emission limit in this paragraph is based on measurement instrumentation employing an average detector. The provisions in 15.35 for limiting peak emissions apply. (b) The field strength of any emissions appearing between the band edges and up to 10 kHz above and below the band edges shall be attenuated at least 26 dB below the level of the unmodulated carrier or to the general limits in 15.209, whichever permits the higher emission levels. The field strength of any emissions removed by more than 10 kHz from the band edges shall not exceed the general radiated emission limits in 15.209. All signals exceeding 20 microvolts/meter at 3 meters shall be reported in the applica- tion for certification. (c) For a home-built intentional radiator, as defined in 15.23(a), operating within the band 49.82-49.90 MHz, the following standards may be employed: (1) The RF carrier and modulation products shall be maintained within the band 49.82-49.90 MHz. (2) The total input power to the device measured at the battery or the power line terminals shall not exceed 100 milliwatts under any condition of modulation. (3) The antenna shall be a single element, one meter or less in length, per- manently mounted on the enclosure containing the device. (4) Emissions outside of this band shall be attenuated at least 20 dB below the level of the unmodulated carrier. (5) The regulations contained in 15.23 of this part apply to intentional radiators constructed under the provisions of this paragraph. (d) Cordless telephones are not permitted to operate under the provisions of this section. 15.237 Operation in the bands 72.0-73.0 MHz, 74.6-74.8 MHz and 75.2-76.0 MHz. (a) The intentional radiator shall be restricted to use as an auditory assise- ance device. . . . 15.238 Operation in the band 88-108 MHz. (a) Emissions from the intentional radiator shall be confined within a band 200 kHz wide centered on the operating frequency. The 200 kHz band shall lie wholly within the frequency range of 88-108 MHz. (b) The field strength of any emissions within the permitted 200 kHz band shall not exceed 250 microvolts/meter at 3 meters. The emission limit in this paragraph is based on measurement instrumentation employing an average detector. The provisions in 15.35 for limiting peak emissions apply. (c) The field strength of any emissions radiated on any frequency out- side of the specified 200 kHz band shall not exceed the general radiated emis- sion limits in 15.209. 15.241 Operation in the band 174-216 MHz. (a) Operation under the provisions of this section is restricted to bio- medical telemetry devices. . . . 15.243 Operation in the band 890-940 MHz. (a) Operation under the provisions of this section is restricted to devices that use radio frequency energy to measure the characteristics of a mate- rial. Devices operated pursuant to the provisions of this section shall not be used for voice communications or the transmission of any other type of mes- sages. . . . 15.245 Operation within the bands 902-928 MHz, 2435-2465 MHz, 5785- 5815 MHz, 10500-10550 MHz, and 24075-24175 MHz. (a) Operation under the provisions of this section is limieed to intentional radiators used as field disturbance sensors, excluding perimeter protection systems. . . . 15.247 Operation within the band 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz. (a) Operation under the provisions of this section is limited to frequency hopping and direct sequence spread spectrum intentional radiators that comply with the following provisions: (1) Frequency hopping systems shall have hopping channel carrier fre- quencies separated by a minimum of 25 kHz or the 20 dB bandwidth of the hop ping channel, whichever is greater. The system shall hop to channel fre- quencies that are selected at the system hopping rate from a pseudorandomly ordered list of hopping frequencies. Each frequency must be used equally on the average by each transmitter. The system receivers shall have input bandwidths that match the hopping channel bandwidths of their corresponding transmitters and shall shift frequencies in synchronization with the transmitted signals. (i) Frequency hopping systems operating in the 902-928 MHz band shall use at least 50 hopping frequencies. The maximum allowed 20 dB bandwidth of the hopping channel is 500 hHz. The average time of occupancy on any fre- quency shall not be greater than 0.4 seconds within a 20 second period. (ii) Frequency hopping systems operating in the 2400-2483.5 MHz and 5725- 5850 MHz bands shall use at least 75 hopping frequencies. The maximum 20 dB bandwidth of the hopping channel is 1 MHz. The average time of occupancy on any frequency shall not be greater than 0.4 seconds within a 30 second pe- riod. (2) For direct sequence systems, the minimum 6 dB bandwidth shall be at least 500 kHz. (b) The maximum peak output power of the transmitter shall not exceed 1 Watt. If transmitting antennas of directional gain greater than 6 dBi are used, the power shall be reduced by the amount in dB that the directional gain of the antenna exceeds 6 dBi. (c) If any 100 kHz bandwidth outside these freguency bands, the radio fre- quency power that is produced by the modulation products of the spreading sequence, the information seguence and the carrier freguency shall be ei- ther at least 20 dB below that in any 100 kHz bandwidth within the band that contains the highest level of the desired power or shall not exceed the general levels specified in 15.209(a), whichever results in the lesser attenu- ation. All other emissions outside these bands shall not exceed the gen- eral radiated emission limits specified in 15.209(a). (d) For direct seguence systems, the transmitted power density averaged over any 1 second interval shall not be greater than 8 dBm in any 3 kHz band- width within these bands. (e) The processing gain of a direct sequence system shall be at least 10 dB. The processing gain shall be determined from the ratio in dB of the sig- nal to noise ratio with the system spreading code turned off to the signal to noise ratio with the system spreading code turned on, as measured at the demodulated output of the receiver. (f) Hybrid systems that employ a combination of both direct sequence and frequency hopping modulation techniques shall achieve a processing gain of at least 17 dB from the combined techniques. The frequency hop- ping operation of the hybrid system, with the direct sequence operation turned off, shall have an average time of occupancy on any frequency not to exceed 0.4 seconds within a time period in seconds equal to the number of hop- ping frequencies employed multiplied by 0.4. The direct sequence operation of the hybrid system, with the frequency hopping operation turned off, shall comply with the power density requirements of paragraph (d) of this section. NOTE: Spread spectrum systems are sharing these bands on a noninterference basis with systems supporting critical Government requirements...secondary only to ISM equipment operated under the provisions of part 18 of this chapter. Many of these Government systems are airborne radiolocation systems that emit a high EIRP which can cause interference to other users. Also, investigations of the effect of spread spectrum interference to U. S. Government operations in the 902-928 MHz band may require a future decrease in the power limits allowed for spread spectrum operation. 15.249 Operation within the bands 902-928 MHz, 2400-2483.5 MHz, 5725-5875 MHZ, and 24.0-24.25 GHz. (a) The field strength of emissions from intentional radiators operated within these frequency bands shall comply with the following: ================================================================ Field strength Field strength Fundamental frequency of fundamental of harmonics (millivolts/m) (microvolts/m) ---------------------------------------------------------------- 902-928 MHz ................... 5O 500 2400-2483.5 MHz ............... 50 500 5725-5875 MHz ................. 50 500 24.0-24.25 GHz ................ 250 2500 ================================================================ (b) Field strength limits are specified at a distance of 3 meters. (c) Emissions radiated outside of the specified frequency bands, except for harmonics, shall be attenuated by at least 50 dB below the level of the fun- damental or to the general radiated emission limits in 15.209, whichever is the lesser attenuation. (d) As shown in 15.35(b), for frequencies above 1000 MHz, the above field strength limits are based on average limits. However, the peak field strength of any emission shall not exceed the maximum permitted average limits specified above by more than 20 dB under any condition of modulation. 15.251 Operation within the bands 2.9-3.26 GHz, 5.267-3.332 GHz, 3.339- 3.3458 GHz, and 3.358-3.6 GHz. (a) Operation under the provisions of this section is limited to automatic vehicle identification systems . . . .