I don't think that Chris stands corrected!! I think the Mr. Pozner made some errors in his reading and interpretation of the code and left out important information in his technical paper. First, Sec 15.201 specifically deals with the certification of Carrier Current Systems which does not apply to 802.11. Sec 15.203 deals with non-removable antennas (baby monitors, phones) but makes exception for Carrier Current Systems and other intentional radiators which must be measured in accordance with Sec 15.31(d). Mr Pozner's concentration on point (c) of sec 15.204 was a misrepresentation of that section as set forth by the sectional premise Here is the Kicker. None of the above matters because it is ALL superceded by the specific allowances set forth in Sec 15.247 and 15.249 with regards to operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz. In this case an antenna just needs to meet the technical requirements. I have included below the aboved referenced items. :-) For those of you that like to read go to: http://www.access.gpo.gov/cgi-bin/cfrassemble.cgi?title=199947 Better than a glass of warm milk to put you to sleep. S. Earl Jarosh (ex. Steve?) N0HZ (ex. KA0VYB) No Hertz, No Gain 612-868-1313 earl at jarosh.org earljarosh at moneycenters.com www.moneycenters.com > Chris Cox wrote: > > Well, I stand corrected! I was sure that I had read somewhere that using > > gain antennae was fine, as long as you reduced the TX power by 1dB for > > each 3dB of gain added. Perhaps that only applies though if you're using > > an antenna supplied by the manufacturer of the equipment. > Andy Warner wrote: > I think Matthew's point was FCC part 15 certification, or > lack thereof in anything modified after purchase (where > modification can be interpreted as adding a 3rd party > antenna) - which is a rat-hole I don't intend to get sucked > down. Correct me if I'm wrong, Matthew. TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION PART 15--RADIO FREQUENCY DEVICES--Table of Contents Subpart C--Intentional Radiators Sec. 15.203 Antenna requirement. An intentional radiator shall be designed to ensure that no antenna other than that furnished by the responsible party shall be used with the device. The use of a permanently attached antenna or of an antenna that uses a unique coupling to the intentional radiator shall be considered sufficient to comply with the provisions of this section. The manufacturer may design the unit so that a broken antenna can be replaced by the user, but the use of a standard antenna jack or electrical connector is prohibited. This requirement does not apply to carrier current [[Page 693]] devices or to devices operated under the provisions of Sec. 15.211, Sec. 15.213, Sec. 15.217, Sec. 15.219, or Sec. 15.221. Further, this requirement does not apply to intentional radiators that must be professionally installed, such as perimeter protection systems and some field disturbance sensors, or to other intentional radiators which, in accordance with Sec. 15.31(d), must be measured at the installation site. However, the installer shall be responsible for ensuring that the proper antenna is employed so that the limits in this part are not exceeded. [54 FR 17714, Apr. 25, 1989, as amended at 55 FR 28762, July 13, 1990] TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION PART 15--RADIO FREQUENCY DEVICES--Table of Contents Subpart C--Intentional Radiators Sec. 15.204 External radio frequency power amplifiers and antenna modifications. (a) Except as otherwise described in paragraph (b) of this section, no person shall use, manufacture, sell or lease, offer for sale or lease (including advertising for sale or lease), or import, ship, or distribute for the purpose of selling or leasing, any external radio frequency power amplifier or amplifier kit intended for use with a Part 15 intentional radiator. (b) A transmission system consisting of an intentional radiator, an external radio frequency power amplifier, and an antenna, may be authorized, marketed and used under this part. However, when a transmission system is authorized as a system, it must always be marketed as a complete system and must always be used in the configuration in which it was authorized. An external radio frequency power amplifier shall be marketed only in the system configuration with which the amplifier is authorized and shall not be marketed as a separate product. (c) Only the antenna with which an intentional radiator is authorized may be used with the intentional radiator. [62 FR 26242, May 13, 1997] TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION PART 15--RADIO FREQUENCY DEVICES--Table of Contents Subpart D--Unlicensed Personal Communications Service Devices Sec. 15.319 General technical requirements. (a) The 1910-1920 MHz and 2390-2400 MHz bands are limited to use by asynchronous devices under the requirements of Sec. 15.321. The 1920- 1930 MHz sub-band is limited to use by isochronous devices under the requirements of Sec. 15.323. (b) All transmissions must use only digital modulation techniques. (c) Peak transmit power shall not exceed 100 microwatts multiplied by the square root of the emission bandwidth in hertz. Peak transmit power must be measured over any interval of continuous transmission using instrumentation calibrated in terms of an rms-equivalent voltage. The measurement results shall be properly adjusted for any instrument limitations, such as detector response times, limited resolution bandwidth capability when compared to the emission bandwidth, sensitivity, etc., so as to obtain a true peak measurement for the emission in question over the full bandwidth of the channel. (d) Power spectral density shall not exceed 3 milliwatts in any 3 kHz bandwidth as measured with a spectrum analyzer having a resolution bandwidth of 3 kHz. (e) The peak transmit power shall be reduced by the amount in decibels that [[Page 714]] the maximum directional gain of the antenna exceeds 3 dBi. (f) The device shall automatically discontinue transmission in case of either absence of information to transmit or operational failure. The provisions in this section are not intended to preclude transmission of control and signaling information or use of repetitive codes used by certain digital technologies to complete frame or burst intervals. (g) Notwithstanding other technical requirements specified in this subpart, attenuation of emissions below the general emission limits in Sec. 15.209 is not required. (h) Where there is a transition between limits, the tighter limit shall apply at the transition point. (i) Unlicensed PCS devices are subject to the radiofrequency radiation exposure requirements specified in Secs. 1.1307(b), 2.1091 and 2.1093 of this chapter, as appropriate. All equipment shall be considered to operate in a ``general population/uncontrolled'' environment. Applications for equipment authorization of devices operating under this section must contain a statement confirming compliance with these requirements for both fundamental emissions and unwanted emissions. Technical information showing the basis for this statement must be submitted to the Commission upon request. [58 FR 59180, Nov. 8, 1993, as amended at 59 FR 32852, June 24, 1994; 59 FR 40835, Aug. 10, 1994; 60 FR 13073, Mar. 10, 1995; 61 FR 41018, Aug. 7, 1996] [Page 705-707] TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION PART 15--RADIO FREQUENCY DEVICES--Table of Contents Subpart C--Intentional Radiators Sec. 15.247 Operation within the bands 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 frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of the hopping channel, whichever is greater. The system shall hop to channel frequencies 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) For frequency hopping systems operating in the 902-928 MHz band: if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the system shall use at least 50 hopping frequencies and the average time of occupancy on any frequency shall not be greater than 0.4 seconds within a 20 second period; if the 20 dB bandwidth of the hopping channel is 250 kHz or greater, the system shall use at least 25 hopping frequencies and the average time of occupancy on any frequency shall not be greater than 0.4 seconds within a 10 second period. The maximum allowed 20 dB bandwidth of the hopping channel is 500 kHz. [[Page 706]] (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 period. (2) For direct sequence systems, the minimum 6 dB bandwidth shall be at least 500 kHz. (b) The maximum peak output power of the intentional radiator shall not exceed the following: (1) For frequency hopping systems operating in the 2400-2483.5 MHz or 5725-5850 MHz band and for all direct sequence systems: 1 watt. (2) For frequency hopping systems operating in the 902-928 MHz band: 1 watt for systems employing at least 50 hopping channels; and, 0.25 watts for systems employing less than 50 hopping channels, but at least 25 hopping channels, as permitted under paragraph (a)(1)(i) of this section. (3) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of this section, if transmitting antennas of directional gain greater than 6 dBi are used the peak output power from the intentional radiator shall be reduced below the stated values in paragraphs (b)(1) or (b)(2) of this section, as appropriate, by the amount in dB that the directional gain of the antenna exceeds 6 dBi. (i) Systems operating in the 2400-2483.5 MHz band that are used exclusively for fixed, point-to-point operations may employ transmitting antennas with directional gain greater than 6 dBi provided the maximum peak output power of the intentional radiator is reduced by 1 dB for every 3 dB that the directional gain of the antenna exceeds 6 dBi. (ii) Systems operating in the 5725-5850 MHz band that are used exclusively for fixed, point-to-point operations may employ transmitting antennas with directional gain greater than 6 dBi without any corresponding reduction in transmitter peak output power. (iii) Fixed, point-to-point operation, as used in paragraphs (b)(3)(i) and (b)(3)(ii) of this section, excludes the use of point-to- multipoint systems, omnidirectional applications, and multiple co- located intentional radiators transmitting the same information. The operator of the spread spectrum intentional radiator or, if the equipment is professionally installed, the installer is responsible for ensuring that the system is used exclusively for fixed, point-to-point operations. The instruction manual furnished with the intentional radiator shall contain language in the installation instructions informing the operator and the installer of this responsibility. (4) Systems operating under the provisions of this section shall be operated in a manner that ensures that the public is not exposed to radio frequency energy levels in excess of the Commission's guidelines. See Sec. 1.1307(b)(1) of this chapter. (c) In any 100 kHz bandwidth outside the frequency band in which the spread spectrum intentional radiator is operating, the radio frequency power that is produced by the intentional radiator shall be at least 20 dB below that in the 100 kHz bandwidth within the band that contains the highest level of the desired power, based on either an RF conducted or a radiated measurement. Attenuation below the general limits specified in Sec. 15.209(a) is not required. In addition, radiated emissions which fall in the restricted bands, as defined in Sec. 15.205(a), must also comply with the radiated emission limits specified in Sec. 15.209(a) (see Sec. 15.205(c)). (d) For direct sequence systems, the peak power spectral density conducted from the intentional radiator to the antenna shall not be greater than 8 dBm in any 3 kHz band during any time interval of continuous transmission. (e) The processing gain of a direct sequence system shall be at least 10 dB. The processing gain represents the improvement to the received signal-to-noise ratio, after filtering to the information bandwidth, from the spreading/despreading function. The processing gain may be determined using one of the following methods: (1) As measured at the demodulated output of the receiver: the ratio in dB of the signal-to-noise ratio with the system spreading code turned off to the [[Page 707]] signal-to-noise ratio with the system spreading code turned on. (2) As measured using the CW jamming margin method: a signal generator is stepped in 50 kHz increments across the passband of the system, recording at each point the generator level required to produce the recommended Bit Error Rate (BER). This level is the jammer level. The output power of the intentional radiator is measured at the same point. The jammer to signal ratio (J/S) is then calculated, discarding the worst 20% of the J/S data points. The lowest remaining J/S ratio is used to calculate the processing gain, as follows: Gp = (S/N) o + Mj + Lsys, where Gp = processing gain of the system, (S/N) o = signal to noise ratio required for the chosen BER, Mj = J/S ratio, and Lsys = system losses. Note that total losses in a system, including intentional radiator and receiver, should be assumed to be no more than 2 dB. (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 hopping 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 hopping 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. (g) Frequency hopping spread spectrum systems are not required to employ all available hopping channels during each transmission. However, the system, consisting of both the transmitter and the receiver, must be designed to comply with all of the regulations in this section should the transmitter be presented with a continuous data (or information) stream. In addition, a system employing short transmission bursts must comply with the definition of a frequency hopping system and must distribute its transmissions over the minimum number of hopping channels specified in this section. (h) The incorporation of intelligence within a frequency hopping spread spectrum system that permits the system to recognize other users within the spectrum band so that it individually and independently chooses and adapts its hopsets to avoid hopping on occupied channels is permitted. The coordination of frequency hopping systems in any other manner for the express purpose of avoiding the simultaneous occupancy of individual hopping frequencies by multiple transmitters is not permitted. Note: Spread spectrum systems are sharing these bands on a noninterference basis with systems supporting critical Government requirements that have been allocated the usage of these bands, 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. [54 FR 17714, Apr. 25, 1989, as amended at 55 FR 28762, July 13, 1990; 62 FR 26242, May 13, 1997] _______________________________________________ Twin Cities Wireless Users Group Mailing List - Minneapolis/St. Paul, Minnesota http://www.tcwug.org tcwug-list at tcwug.org https://mailman.real-time.com/mailman/listinfo/tcwug-list