Wireless Product Testing William H' Graff, AmericanTCB

1
Wireless Product TestingWilliam H. Graff,
AmericanTCB
2
FCC 47 CFR Regulations

• Part 2 General Requirements
• Part 15B Unintentional Radiators
• Part 15C/D/E/F Intentional Radiators
• Part 18 ISM Devices
• All Other Rule Parts Licensed Devices

3
Part 2 General Requirements

• Basic reference section on how to create an FCC
  filing.
• Oldest part of the FCC rules.
• All necessary requirements begin with Part 2
• FCC Rules predate industry standards

4
Equipment Authorizations

• There are three basic types of equipment
  authorizations
• Verification
• Declaration of Conformity
• Certification

5
Verification

• Simplest of all Equipment Authorizations
• No submission to FCC
• Data is held by Applicant/Manufacturer
• Proof that equipment was tested and found to be
  compliant at a given point in time
• Examples Broadcast Receivers, TVs, Class A
  Digital Devices, BPL (consumer)

6
Declaration of Conformity

• More complex than Verification
• No submission to FCC
• Must be done at an Accredited Laboratory
• Country where testing takes place must have
  signed MRA with USA
• Responsible Party must reside on US soil
• Examples Class B computers and peripherals,
  microwave ovens for consumers,

7
Certification

• Used for all equipment authorizations involving
  Licensed or Unlicensed transmitters.
• Can be used optionally for Class B
  computers/peripherals, comsumer microwave ovens,
  etc.
• Submission to FCC database is mandatory
• Is more than just an engineering report. It is
  a legal document.
• Requires a detailed list of Exhibits (See
  2.1033)
• Examples All Licensed transmitters, all
  Unlicensed Part 15 Intentional Radiators, radar
  detectors, scanning receivers

8
Changes to Certified Equipment

• Known as Permissive Change
• Changes which have no effect on RF emissions or
  performance Class 1
• Changes which affect emissions or performance but
  still within the limits Class 2
• Changes to RF software Class 3 This is only
  applicable to devices which qualify as Software
  Defined Radio (SDR)

9
Class I Permissive Change

• Changes which have no effect on the emission
  characteristics of a device
• No submission to FCC
• Test Report is created, but held by Applicant /
  Manufacturer
• Examples Color

10
Class II Permissive Change

• Changes which may potentially affect the
  emissions of a device
• Submission required to FCC
• Examples New PCB layout, new antenna, new host
  (re modular approval)

11
Forbidden Class II Changes(requires new ID / new
submission)

• Changes to frequency determining circuit
• Changes in RF power
• Changes from one RF category to another
• Changes to modulation or timing
• Changes in basic functionality (i.e. dual band to
  single band)

12
Permit-But-Ask ProcedureNew! as of November,
2006

• FCC has initiated a new procedure for
  troublesome filings and new technology. Prior
  to any request for Certification, a TCB must
  request guidance from FCC on specific items to
  look for before granting Certification.
• Specifically aimed (so far) at 15.239 personal FM
  transmitters, WiMax devices and 3.5/4G
  cellphones.
• See FCC Memo to TCBs.

13
Licensed Transmitter Approvals
14
Licensed Radio Services General Testing
Requirements

• FCC Part 2.1046 through 2.1057 Cover tests for
  all licensed devices.
• The basics rationale of all FCC tests originate
  within this section. This is the oldest of the
  FCC rules
• Built for the narrowband world, but still
  adaptable to broadband radio concepts

15
Licensed Radio Services Test Parameters

• 2.1046 - Power Output
• 2.1047 - Modulation Characteristics
• 2.1049 - Occupied Bandwidth
• 2.1051 - Antenna Terminal Spurious Emissions
• 2.1053 - Radiated Spurious Emissions
• 2.1055 - Frequency Stability for Temperature and
  Voltage Variations

16
Licensed Radio Services Test Parameters

• Remember that the purpose of performing the
  measurements required and submitting
  interpretations is to establish compliance with
  the technical requirement contained in the Radio
  Service Rules. These rules are pre-standards.
  In other words they evolved before there were
  generally accepted measurement standards and
  practices.

17
Basic Test Parameters

• Power Output 2.1046
• Traditionally thought of as a caloric
  measurement. Use of common CW power meters were
  common. Great deal of measurement certainty.
• Part 15 began the usage of peak reading power
  meters. Most unlicensed transmitter sections
  still require the concept of peak power unless
  specifically stated otherwise

18
Basic Test Parameters

• Modulation Characteristics 2.1047
• For analog radio transmissions (AM, FM, SSB)
  understanding basic parameters such as audio
  response and audio low pass filter were necessary
  to determine compliance. Testing usually required
• For todays constant envelope digital
  modulation systems this is basically unnecessary,
  but still must be described. Testing usually not
  required.

19
Basic Test Parameters

• Occupied Bandwidth 2.1049
• Occupied Bandwidth is defined as that portion of
  the spectrum where 99 of the emitted energy
  exists. The results are used to compare modulated
  spectrum with emissions masks.
• Although not explicitly specified, all
  Certification reports including Part 15 must have
  an occupied bandwidth plot
• Plot should be presented for each type of
  modulation

20
Basic Test Parameters

• Antenna Terminal Spurious Emissions 2.1051
• (Also known as Antenna Conducted Emissions)
• View levels of conducted harmonics applied to the
  antenna.
• An extension of the occupied bandwidth test. Show
  spurious emissions to 10th harmonic.
• Unless specified elsewhere, RBW should be equal
  or greater than Tx emission bandwidth

0
21
Basic Test Parameters

• Field Strength of Spurious Emissions 2.1053
• Test includes emissions radiated from the
  cabinet, chassis, and associated wiring. The
  specification is the same emission mask under the
  Radio Service rules extended to the highest
  frequency specified in 2.1057. Traditionally a
  terminated transmitter is tested without
  antenna.
• For Licensed equipment, the substitution method
  described in TIA/EIA 603 is the required test
  procedure.
• For Part 15 emissions testing, direct measurement
  of field strength is accepted. Device must be
  tested with its antenna in place.

22
Basic Test Parameters

• Frequency Stability 2.1055
• Done over temperature -30 C to 50 C and
  operating voltage /- 15 specifications.
• Battery operated devices should also include
  B.E.P Battery End Point
• Usually defined in ppm but other units such as
  Hz, are accepted as defined in specific rule
  section.
• In most cases, frequency stability is not
  required for Part 15

23
Certification Checklist Check for Accuracy

• Applicant name, address, contact info, email
  address. There must be agreement with the
  supplied contact information and the Grantee
  contact information at FCC website.
• Agent Authorization Letter
• Confidentiality Request Letter
• FCC ID
• Equipment Class if not known ask!
• Rule Part(s)
• Frequency Range
• Power Output
• Requested Emission Designator

24
Certification Checklist

• Associated Application (Composite Request)
• Confidentiality Request (See separate details for
  STC)
• Details to be included with confidentiality.
• Block Diagram
• Schematics
• Operational Description
• Parts/Tune Up
• Statement / letter supplied for special
  requirements or interagency coordination (if
  required).

25
Licensed and Unlicensed Transmitter Exhibits

• Certification Requirements for exhibits,
  labeling, etc, differ somewhat from the Licensed
  world.
• Compare 2.1033(c) Licensed Tx with 2.1033(b)
  Part 15 for Exhibit list
• Compare 15.19(a)(3) with 15.19(a)(1) for label
  language. Devices which are Licensed transmitters
  only with no accociated receiver can omit all
  15.19 langrage
• All Part 15 devices must address 15.21 and 15.105
  for manual
• RF Exposure language is additional

26
Unlicensed Part 15 Transmitter Approvals
27
Part 15 Rule Organization

• All general rules including measurement
  procedures, label requirements, etc. are located
  in 15.xx (Subpart A)
• All Unintentional Radiators are located in Part
  15.1xx of the Rules (Subpart B)
• All Intentional Radiators are located in the
  15.2xx sections of the Rules (Subpart C), 15D
  (unlicensed PCS), 15E (UNII) and 15F (UWB)

28
Essential Part 15 Transmitter Requirements

• 15.203 Antenna Requirements
• 15.204 External amplifier restrictions
• 15.205 Restricted Bands
• 15.207 Conducted Requirements
• 15.209 Radiated Requirements

29
15 C Intentional Radiators

• Special note FCC 15.207 FCC 15.209
• Equivalent to 15.107 and 15.209 Class B computer
  limits.
• Unless indicated otherwise, all spurious
  emissions from Part 15 transmitters should be to
  these limits.

30
15.203 Antenna Requirements

• 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.

31
15.204 Power Amp Restrictions

• Officially referred to as a Transmission System
• For spread spectrum transmitters usually includes
  the bi-directional amplifier, DC injector, and
  spread spectrum transceiver under one FCC ID
• Amplifiers designed for use with Spread Spectrum
  Systems must be approved as part of the system
  and marketed as part of a complete package.
  Amplifiers cannot be marketed without pairing to
  specific transceiver.
• Only approved antennas may be sold with the
  product. New antenna can be added under the Class
  II PC process.

32
15.205 Restricted Bands

• Bands are generally US Government and military
• The field strength of emissions appearing within
  these frequency bands shall not exceed the limits
  shown in 15.209.
• Basis for all radiated band edge requirements.
• Caution Restricted Bands change over time

33
AC Conducted Limits 15.207

• Except for battery-only powered devices, all Part
  15 transmitters must have AC Conducted test. This
  includes Modular Approvals under DA 00-1407
• Conducted emissions not required for battery
  powered devices that make no provisions for
  attachment to AC power.
• Follow test procedure in ANSI C63.4
• Unless otherwise specified, all Intentional
  Radiators must meet 15.207 limits.

34
Radiated Emission Limits 15.209

• Unless specified elsewhere, all Intentional
  Radiators must meet 15.209 limits anywhere
  outside of their allotted frequency band.
• Test set-up per ANSI C 63.4 limits.
• Limits identical to FCC Class B. Tighter limits
  apply at all band edges
• Watch for specific rules for the device.
• Intentional radiators must generally be measured
• to the 10th Harmonic

35
Part 15 C Intentional Radiators

• 15.215 Additional Provisions to the General
  Radiated Emission Limitations
• Prolog to 15.217 to 15.255
• 15.215(b) Emissions outside parking space must
  meet Class B limits.
• 15.215(c) Emissions should stay within central
  80 of band.
• 15.215(d) Emissions must take into account
  sweeping, hopping and other modulation techniques
  including OOK

36
Part 15 C Intentional Radiators

• 15.217 Operation in the band 160-190 kHz.
• 15.219 Operation in the band 510-1705 kHz
• 15.221 Operation in the band 525-1705 kHz.
• 15.223 Operation in the band 1.705-10 MHz.
• 15.225 Operation within the band 13.110-14.010
  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 40.66-40.70 MHz and
  above 70 MHz.
• 15.233 Operation within the bands 43.71-44.49
  MHz, 46.60-46.98 MHz, 48.75-49.51 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.
• 15.240 Operation in the band 433.5-434.5 MHz.
• 15.241 Operation in the band 174-216 MHz.
• 15.242 Operation in the bands 174-216 MHz and
  470-668 MHz.
• 15.243 Operation in the band 890-940 MHz.
• 15.245 Operation within the bands 902-928 MHz,
  2435-2465 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 Operation within the bands 902-928 MHz,
  2400-2483.5 MHz, 5725-5875 MHZ, and 24.0-24.25
  GHz.

37
Part 15 Most Common Sections

• 15.227 27MHz Toys
• 15.231 Momentary-On Remote Controls
• 15.235 49MHz Toys
• 15.239 88 - 108 MHz Personal FM Transmitters
• 15.247 Spread Spectrum Transmitters
• 15.407 UNII Devices

38
Part 15D - Unlicensed PCS Bands

• 1910 - 1930 MHz
• 2390 - 2400 MHz
• Unique Antenna Connector Required
• 3 dBi Max (1 to 1 Power Reductions vs. antenna
  gain)
• OK for TCB approval
• Rarely used FCC section. But more activity this
  past year as this section has recently been
  re-written
• Still very complicated.

39
Part 15E - UNIIUnlicensed National Information
Infrastructure

• 5.15 - 5.25 GHz
• 5.25 - 5.35 GHz
• 5.47 - 5.725
• 5.725 - 5.825 GHz
• 802.11a transmitters
• Specific power and usage limitations for each
  band
• Indoor use only in the 5.25 - 5.35 GHz band.
• DFS compliance required filing to FCC
• Also shared with 15.247

40
Part 15 F UWB (Ultra-Wide Band)

• Adopted in April of 2002
• Does not yet qualify for TCB Approval
• No standardized test procedures yet adopted
• Devices range from see-through-wall devices,
  ground radar for construction and safety, to low
  power communication.
• Operates over wide area of band (1 to 3 GHz wide
  signals)

41
Spread Spectrum DevicesDTS/DSSS and FHSS(WiFi
and Bluetooth)
42
Spread Spectrum Definitions

• Direct Sequence and DTS - use a sequential
  modulation to spread a narrow signal over a
  relative broad band.
• Example 802.11b/g
• Frequency Hopper - uses an encoded narrow band
  signal that shifts in a pseudorandmly generated
  frequency shifts.
• Example Bluetooth
• Hybrid a combination of both Frequency Hopping
  and Direct Sequence systems

43
Spread Spectrum Frequencies

• Operate in the Industrial, Scientific, and
  Medical bands on a secondary basis.
• ISM bands are global and not restricted by ITU
  regions
• No protection from interference
• 902 - 928 MHz
• 2400 - 2483.5 MHz
• 5725 - 5850 MHz

44
WiFi 802.11b/g channels

• FCC rule interpretations do not allow the end
  user to select the country or region, nor do they
  allow the end user to download International
  driver channel sets. The only legal channels are
  Channel 1 (2412MHz) to Channel 11 (2462 MHz)

45
FCC Rules for Spread Spectrum Transmitters

• Power Output 1 Watt Max (except for specific
  cases)
• EIRP 4 Watts Max (except Point to Point)
• Antenna Gain limited to 6 dBi without power
  reduction from transmitter of 1 dB power for
  every 1 dB antenna exceeds 6 dBi
• Unique antenna connector required (except under
  professional installation)

46
Additional FCC Requirements

• For systems operating strictly as a Point to
  Point systems
• in the 2400 - 2483.5 MHz band, the power
  reduction requirement is 1 dB for every 3 dB the
  antenna exceeds 6 dBi
• in the 5725 - 5850 MHz band may employ antennas
  with directional gain greater than 6 dBi without
  reduction in transmitter output power.

47
Additional Requirements

• Must Operate on Non-Interference Basis (cannot
  interfere with others)
• Must accept that interference may affect
  operation no legal recourse
• Out of Band requirements including being 20 dBc
  down in any 100 kHz outside the Band of Operation
  (In reality, 75 dBc down from peak in the
  Restricted Bands is probably necessary)

48
Spread Spectrum Testing

• Radio testing typically performed in several
  parts
• Lab bench testing for all conducted tests
• Listed open field test site or Semi-Anechoic
  Chamber required for all radiated tests.

49
Spread Spectrum Test Software Requirements

• Must be able to turn on/off transmitter, select
  antenna ports, and go to receive-only mode.
• Must be able to select low , mid, and high
  channels.
• Must be able to run in continuous transmit mode.
  This means without any carrier pulsing. If this
  requirement cannot be met, then additional
  corrections are required for many tests.
• Must be able to check across all data rates and
  modulations.
• For Bluetooth, must be able to set to DH1, DH2,
  DH3

50
MIMO (802.11n) Considerations

• 802.11n is not a huge compliance issue.
• Be sure to measure RF Pout across each chain or
  output port
• Pout on Grant will be sum of all powers.
• SAR measurements are still under development by
  the Commission. Some guidance is available

51
Family Antenna Approvals

• Allows the use similar antennas without
  re-testing or filing a Class II Change.
• Example A 2dBi inverted-f antenna originally
  approved for use with a specific device. A
  manufacturer can substitute a 0dBi inverted-f
  from a different supplier without re-testing as
  long as conducted TX output power remains the
  same
• If new antenna of greater gain or different type,
  then Class II PC must be filed.

52
Modular Approval - DA00-1407

• Must have its own FCC ID number on the module
  itself.
• An ID inside manual is never sufficient.
• An additional label is required on the outside of
  the final host device with wording such as
• Contains Inside FCC ID XXXxxx
• Must meet the Requirements of OET 65 for RF Safety

53
Full Modular Approvals

• By Definition, these transmitters must have own
  reference oscillator. In addition a separate
  letter on Applicant letterhead addressing all
  these items must accompany the filing
• RF shielding.
• Buffered data input/output ports
• Power supply regulation
• Permanent antenna or unique connector
• Testes in stand alone condition
• Labeled with own ID number
• Instructions to operator / OEM integrator
• Must meet RF Exposure requirements.

54
Limited Modular Approval (LMA)

• If any of the 8 elements on the preceding slide
  cannot be met, a limited modular approval may be
  obtained in some circumstances. LMAs define
  special circumstances where Certification is
  valid
• Example 1 Wireless mini-PCI 802.11b/g card
  without voltage regulation
• Example 2 Wireless mini-PCI 802.11b/g card with
  SAR results which may apply to a specific chassis
  or model notebook PC host.

55
15.203 Unique Connector Requirement

• Standard Connectors now include
• SMA, TNC, BNC are not allowed
• MMCX, MCX and reverse SMA,TNC are possible
  candidates for in this list
• Integral Antenna requirements which used to be
  part of 15.407 have been eliminated

56
15.204 Power Amplifier Restrictions

• Must be seen as a complete end-to-end
  transmission system.
• Must include seperately approved transmitter and
  antenna, in addition to amplifier.
• Amplifiers designed for use with Spread Spectrum
  Systems must be approved as part of the system
  and marketed as part of a complete package.
• Additional clarification to 15.204 requirements
  exist in FCC Knowledgebase.

57
Spread Spectrum RF Exposure Requirements

• 15.247 (b)(4) System shall be operated to
  ensure that public is not exposed to levels of RF
  emissions that exceed the recommended FCC
  Guidelines
• References
• OET 65 Supplement C
• TCB July 17, 2002 Exclusion list

58
General RF Exposure Definitions

• Fixed or mast mounted on permanent outdoor
  structures.
• Mobile equipment - greater than 20 cm to the body
• Portable equipment -20 cm or less to the body.
• Note A device may be subject to multiple
  categories depending on its use. In this specific
  case, particular attention must be all possible
  usage conditions.

59
Spread Spectrum RF Exposure Requirements

• Fixed and Mobile Devices must meet OET-65 MPE RF
  Safety Requirements (1 mW/cm2 for 2.4 GHz
  Devices)
• Portable devices are subject to SAR evaluation
  when conducted or EIRP output power is greater
  than 60/f(GHz) if contact with antenna is
  possible, or 120mW/f(GHz) if a distance of 2.5cm
  can be assured.
• Does not apply to 15.407 UNII 802.11a. All RF
  category Portable 802.11a devices must undergo
  SAR evaluation regardless of RF Pout

60
Spread Spectrum Test System Requirements

• All reading below 1 GHz in Quasi-Peak.
• All readings in both Peak and Average above 1
  GHz.
• Plots of Band Edge Measurements or Marker Delta
  method

61
Spread Spectrum Testing

• Transmit Power Peak Measurement - Antenna
  conducted measurement
• Use power meter with peak head detector
• Note Certain power meters with VBW
  specifications less than the 6 dB bandwidth of
  the fundamental have caused concern and should be
  avoided
• Diode detector/signal generator substitution
  method with an oscilloscope.
• RMS measurement techniques during the period of
  the data burst allowed.

62
Spread Spectrum Testing

• Radiated Transmit Power Peak Measurement.
• With highest gain of each antenna family
• With lowest gain antenna and EUT at Max Power
• Spectrum Analyzer settings
• RBW 1 MHz
• VBW gt RBW

63
Spread Spectrum Testing

• Band Edge (Radiated) Low and Highest Frequency of
  operation
• Peak Readings
• RBW 1 MHz VBW gt RBW
• Average Readings
• RBW 1 MHz VBW 10Hz

64
Spread Spectrum Testing

• Harmonics (Radiated)
• Frequencies Low, Middle, Highest channels
• Spectrum Analyzer settings
• Peak mode RBW 1 MHz VBW gt RBW
• Average RBW 1 MHz, VBW 10 Hz. Average
  method assumes carrier is at 100 transmit duty
  cycle. Different settings may need to be
  employed if duty cycle is less than 100

65
Spread Spectrum

• Class II changes cover
• Addition of second antenna
• Modification of RF Exposure report
• Moving from one RF category to another is
  discouraged
• Limited test suites can be used.
• i.e. PCMCIA card with new layout would require
  new SAR test plus radiated emissions only. No
  bench tests required.

66
Spread Spectrum Submittal Requirements

• All spurious emission data above 1 GHz taken with
  average detector, but peak must be provided to
  show compliance with 15.35(b)
• Data and plots (peak average) for band edge
  emissions
• Harmonics (peak average) to 10th harmonic
• TX power (radiated conducted)

67
15.247 Out of Band Emission Requirements

• 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 radiated measurement.

68
Transmitter Power Output Test

• Preferred RF Pout measurement Peak Power Meter
  or RMS during period of data burst
• When measuring RF Conducted Power with spectrum
  analyzer - recommended setting of RBW gt 6 dB of
  EUT emission bandwidth VBW gt RBW

69
Band Edge Testing below 2400 MHz

• Test on Channel 1
• For Frequencies between 2390 - 2400 MHz signals
  must be 20 dBc down from fundamental.
• For 2390 MHz to 2300 - signals must comply with
  15.209 levels (Restricted Bands of 15.205)
• Must test in all data rates.

70
Band Edge Testing above 2483.5 MHz

• Upper restricted band begins at 2483.5 MHz band
  edge - all signals must be compliant to 15.209
  limits
• Difficulties in compliance when 802.11b/g set to
  channel 11. This consistently is the hardest
  test.
• Some equipment programmed to special power limits
  just to comply with restricted band.
• Must test in all data rates

71
Harmonics \ Spurious \ Restricted Bands Testing

• Required for Each transmitter and Antenna
  Combination.
• Lowest, Middle, and Highest Frequency checked
• Worst Case RF Pout/data rate checked
• Up to 10th Harmonic of Fundamental
• Requires Pre Amp and High Pass Filter
• Testing Distance 3 meters

72
FCC Submittal Information

• Test Data
• Max Output Power (at Antenna port and EIRP)
• Quasi-Peak lt 1 GHz
• Both Peak and Average gt 1 GHz
• Plots of Band Edge Measurements or Marker Delta
  method

73
UNII Devices (802.11a)
74
UNII Devices Part 15 Subpart E

• Unlicensed National Information Infrastructure
• Rules adopted in 1997
• These devices are part of the TCB Scope
• Frequencies of Operation
• 5150 - 5250 MHz (Indoor Use Only)
• 5250 - 5350 MHz (DFS/TPC Required)
• 5470 - 5725 MHz (DFS/TPC Required)
• 5725 - 5825 MHz (Shared with 15.247)

75
UNII Devices Part 15 Subpart E

• Transmitter Power Output
• 5150-5250 MHz Band 50 mW
• 5250-5350 MHz Band 250 mW
• 5470-5725 MHz Band 250 mW
• 5725-5825 MHz Band 1 Watt
• All RF category Portable UNII devices must have
  SAR testing

76
UNII Devices Part 15 Subpart E

• All DFS test reports must be approved by FCC
• Client only devices which do not have DFS but
  will change channels in response to commands from
  an access point are allowed to be approved by
  TCBs
• Client only devices must be tested with DFS
  capable golden transmitter
• Client only devices cannot be capable of ad-hoc
  capability

77
UNII Devices Part 15 Subpart E

• Antennas limited to 6 dBi gain without
  transmitter power reduction.
• Low bands may use antennas gt 6 dBi, however
  transmit power and power spectral density must be
  reduced by gain of antenna that exceed 6 dBi
• 5.8 GHz band allows use of up to 23 dBi gain
  antenna for point to point systems without
  transmitter power reduction.

78
Contact Information

• William H. Graff
• President and Director of Engineering
• AmericanTCB, Inc.
• 6731 Whittier Ave.
• McLean, VA 22101
• mailto whgraff_at_ATCB.com
• Corporate Phone [phone]
• Corporate FAX [phone]
• Direct Mobile [phone]
• SKYPE whgraff