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BPL Emission Tests In Briarcliff Manor, NY August 17 - 19, 2004. Steve Martin & Andy Leimer – FCC Laboratory On site support provided by Ambient during emission testing. Outline. Introduction Compliance with Emission Limits BPL Notching

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bpl emission tests in briarcliff manor ny august 17 19 2004

BPL Emission TestsIn Briarcliff Manor, NY August 17 - 19, 2004

Steve Martin & Andy Leimer – FCC Laboratory

On site support provided by Ambient during emission testing

outline
Outline
  • Introduction
  • Compliance with Emission Limits
  • BPL Notching
  • Interference Potential to Mobile Radio in Un-Notched Bands
purpose
Purpose

These tests were initiated in response to written complaints from a local radio amateur who operated a mobile radio in 20-meter band, but the tests were also intended to provide data on BPL emission issues in support of the FCC rule-making process.

frequency allocations of the bpl system

AMATEURBANDS

BPL

BPL

BPL

BPL

BPL

BPL

UnnotchedMobile Test

Complainant

Band

Frequency Allocations of the BPL System

Notched Band

  • The tested BPL system can occupy as many as five bands. One of those bands was “notched” to protect the 20-meter amateur band, used by the complainant

FREQUENCY (MHZ)

briarcliff manor bpl deployment

Relevant BPL device bands

14.4 – 16.3 MHz

19 – 22.8 MHz

Briarcliff Manor BPL Deployment

Traffic

camera

1 mile

(1.6 km)

  • 9 overhead BPL devices
  • 3 “customers” + 1 traffic camera:
    • 2 ConEd employee residences
    • 1 Police station computer

Backhaul

test description for compliance measurements

1.8 MHzHigh-Pass Filter

44 MHzLow-Pass Filter

Test Descriptionfor Compliance Measurements
  • Calibration
    • The combination of all cables & filters was calibrated, as a function of frequency, using the spectrum analyzer’s tracking generator
  • Measurement locations
    • Antenna height: 1 meter
    • Horizontal offset from the power line on which the BPL signals were injected: 10-meters
    • Distance down line (south) from BPL coupler: 0, 0.25, 0.5, 0.75, & 1 wavelength at 15.3 MHz center frequency
    • Two antenna orientations used at each location: (1) Plane of loop vertical & parallel to power line, (2) plane of loop vertical & perpendicular to power line
  • Procedure
    • A broad sweep, band-power measurement was used to ensure that ambient emissions were within the linear range of the analyzer input
    • Power average spectra were measured at each antenna location & orientation. Antenna was returned to the two locations/orientations exhibiting the highest field strengths and the power average spectra were repeated. CISPR quasi-peak measurement was performed in limited band around frequency of maximum emission
  • Distance extrapolation to 30-meter distance, at which emission limit is specified
    • 40 log of slant range from antenna to power line, based on photographically-measured power line height of 10.6 m and horizontal distance of 10 m
    • Extrapolation was applied to the emission limit rather than to the measured data, so that the plots indicate actual field strength observed at the antenna location

Passive Filters

Active loop antennaETS LindgrenModel 6507S/N 1500

SpectrumAnalyzer

Dunestar 400HPF

Sierra Electronic CorpModel 18444

Agilent E7405AS/N US41160309

compliance with emission limits8
Compliance with Emission Limits

BPL COUPLER

  • Device selection
    • BPL medium voltage coupler on Dalmeny Rd was selected for measurement based on complainant’s statement that interference problem was greatest along Dalmeny and Pleasantville Roads and on the fact that the Dalmeny road site provided safe access for testing
  • Results
    • Maximum measured quasi-peak emission was 3.3 dB over limit—an amount within measurement uncertainty

LOOP ANTENNA

equipment setup for notch measurements

1.8 MHzHigh-Pass Filter

44 MHzLow-Pass Filter

Equipment Setupfor Notch Measurements
  • Calibration
    • The combination of all cables and filters was calibrated, as a function of frequency, using the tracking generator in the spectrum analyzer
  • Device under test
    • Medium voltage coupler on Dalmeny Rd
  • Measurement location
    • Antenna placed directly under power line, on a mast, with the loop centered 5.3 meters above the ground, 5 meters downline from the coupler, with the antenna axis horizontal and perpendicular to the line

Passive Filters

  • Active loop antenna:ETS Lindgren Model 6507S/N 1500

SpectrumAnalyzer

Dunestar 400HPF

Sierra Electronic CorpModel 18444

Agilent E7405AS/N US41160309

effectiveness of notch for 20 meter amateur band
Effectiveness of Notchfor 20-meter Amateur Band
  • Tests performed at Dalmeny Rd customer site
  • Notch performance was inadequate—based on peak spectrum observations and radio listening tests
    • Problem 1: Notch was partially filled in by an unnotched BPL device 0.7 miles away
      • Solution during test: Notch on remote device implemented by manufacturer’s representative
    • Problem 2: Polling communications ignore the notch programming
      • An attempt to reduce the problem by increasing polling interval was judged to be inadequate
      • Manufacturer’s proposed near-term solution
        • Shift entire operating band upward
      • Manufacturer’s proposed far-term solution
        • Bug to be fixed in future generation of hardware
  • Notch testing was abandoned pending near-term fix
mobile radio testing
Mobile Radio Testing
  • Monitored signal levels on a mobile receiver connected to a mobile amateur whip antenna while driving through a BPL area(Photo shows van parked under power lines to observe notch depth)

Power line height – 10.6 m

Antenna center height – 3 m

test description for mobile radio signal strength measurements
Test Description for Mobile RadioSignal Strength Measurements

Dell Laptop ComputerModel PP02X

running on battery

  • Signal strength and position logging and mapping for driving tests
    • Signal strength and GPS coordinates were logged at 2-second intervals to comma-delimited .CSV files.
  • Signal strength
    • Signal strength was monitored using the serial port of the receiver. Output has a lower bound of -114 dBm, even when actual signal strength is lower.
    • Antenna and receiver are uncalibrated. Intent of tests are to show relative signal strengths.
  • Receiver mode
    • AM with 5.5 kHz bandwidth
  • Frequency selection
    • Receiver was tuned while away from the BPL area to a frequency having no active transmissions
    • Frequency was selected within the intended downstream injection band of an overhead BPL coupler

15 and 20-meter whip antennas from Iron Horse IHF-5S HF Mobile Antenna Kit (for 21 and 14.285 MHz tests). Antenna was magnetically mounted to top of minivan.

GPS antenna magnetically mounted to top of minivan

ICOM ReceiverModel R-8500

S/N 1201

Garmin GPS-VGPR Receiver

USB-to-SerialConverter

mobile radio received signal strength at 21 2 mhz

Signal Strength(dBm)

Mobile Radio Received Signal Strength at 21.2 MHz

Mobile Radio Received Signal Strength at 21.2 MHz (an unnotched amateur band)

  • Conducted two driving tests while tuned to “dead air” at 21.2 MHz
  • Signal strength is indicated by a color and shape scale from white circles (minimum) to red squares (maximum)
  • Triangular icons show the locations of the three BPL devices that occupied the monitored frequency, as well as six out-of-band BPL devices.
  • The in-band devices injected BPL signals onto the power line continuously—regardless of the presence of data traffic.

BPLDeployment

3 miles

(4.8 km)

BPL devices:In-band (19 – 22.8 MHz)Out-of-band (14.4 – 16.3 MHz)

mobile radio received signal strength at 21 2 mhz18

BPL devices:In-band (19 – 22.8 MHz)Out-of-band (14.4 – 16.3 MHz)

BPL Audibility Bounds:AM at 21.2 MHz

Signal Strength(dBm)

Mobile Radio Received Signal Strength at 21.2 MHz

Mobile Radio Received Signal Strength at 21.2 MHz (an unnotched amateur band)

  • Expanded version of the driving test plot
  • Locations of the “in-band” BPL devices are clearer.
  • Plot also shows BPL Audibility Bounds—explained on the next chart

2 miles

(3.2 km)

mobile radio bpl audibility at 21 2 mhz

BPL devices:In-band (19 – 22.8 MHz)Out-of-band (14.4 – 16.3 MHz)

BPL Audibility Bounds:AM at 21.2 MHz

Mobile Radio BPL Audibility at 21.2 MHz

BPL Audibility Bounds on Mobile Radio at 21.2 MHz (an unnotched amateur band)

  • BPL emissions in the 19 – 22.8 MHz band produced a distinctive tonal sound under AM detection due to the always-on BPL emissions in this band and the OFDM carrier structure
  • During some parts of the driving tests while tuned to “dead air” at 21.2 MHz, coordinates at which BPL signals became inaudible or audible (depending on driving direction) were saved. These are indicated by the black squares on the adjacent map.
  • In general, BPL audibility ended quickly when roads departed from the power lines, but the BPL sounds could be heard at a straight line distance up to 1.7 miles (2.7 km) from the nearest in-band BPL device when power lines followed the road

1.7 mi(2.7 km)

mobile radio received signal strength at 21 2 mhz20

BPL devices:In-band (19 – 22.8 MHz)Out-of-band (14.4 – 16.3 MHz)

BPL Audibility Bounds:AM at 21.2 MHz

Signal Strength(dBm)

Mobile Radio Received Signal Strength at 21.2 MHz

1 mile

(1.6 km)

Further expanded version of the driving test plot (unnotched amateur band)

POINT A

mobile radio received signal strength at 21 2 mhz unnotched amateur band
Mobile Radio Received Signal Strengthat 21.2 MHz (Unnotched Amateur Band)

POINT A

Straight-Line Distance From Point A (Intersection of N. State & Pleasantville Rds) (m)

mobile radio received signal strength at 21 2 mhz versus distance from nearest in band bpl device
Mobile Radio Received Signal Strength at 21.2 MHzVersus Distance from Nearest In-Band BPL Device

Received signal strength is shown as a function of straight line distance to nearest in-band BPL device. Based on aural observations of radio reception, most of the plotted elevated signal levels at distances less than ~1 km are believed to be caused by BPL emissions. Most of those beyond ~1.2 km are believed to originate from other sources.

mobile radio received signal strength at 21 2 mhz versus distance from nearest in band bpl device23
Mobile Radio Received Signal Strength at 21.2 MHzVersus Distance from Nearest In-Band BPL Device

Plot does not separate the effect of distance along the power line, which exhibits a relatively slow dropoff in BPL emissions, and distance away from the power line, which exhibits a rapid dropoff with distance. Variability at a given distance value shown on plot is believed to be caused primarily by differences in distance from the BPL-carrying power line.

Some of the highest peaks may be the result of BPL-carrying power lines passing directly over the road.

test description for mobile radio reception tests with am input

MiniDV VideoCamcorder(Sony DCR-PC100)

Test Description for Mobile Radio Reception Tests With AM Input

Audio CassetteRecorder

w/voice recording

15 or 20-meter whip antenna (from Iron Horse IHF-5S HF Mobile Antenna Kit)--magnetically mounted to top of minivan.

Dell Laptop Computer Model PP02X running on battery

GPS antenna magnetically mounted to top of minivan

  • Signal Source
    • A cassette recording of voice, feeding the modulation input of an RF signal generator, produced an AM modulated signal, which was connected to the receiver input through an attenuator and a directional coupler. An amateur whip antenna was also coupled into the receiver input through the low-loss path of the directional coupler. Generator output level was set to achieve a specified signal level at the receiver input—as monitored by the laptop computer connected to the serial interface on the receiver—with the antenna replaced by a 50-ohm termination.
  • Receiver mode
    • AM with 5.5 kHz bandwidth
  • Recording
    • A video camcorder monitored the view through the windshield and view of the receiver; audio from the receiver’s speaker was recorded through the built-in microphone of the camcorder
    • Audio was also recorded by direct connection of an audio cassette recorder to the receiver audio output.
  • Frequency selection
    • The signal generator and receiver were tuned within an amateur band to a frequency containing no obvious communications. Tests were conducted in an amateur band that was not notched by the BPL system and in one that was notched.
  • Signal strength and position logging and mapping for driving tests
    • As described previously

50-ohmTerm

Sierra 145,DirectionalCoupler

S/N 624

Agilent E4437B

Signal GeneratorS/N US41311043

EI

ICOM ReceiverModel R-8500

S/N 1201

GarminGPS-VReceiver

6-dBAtten

USB-to-SerialConverter

Serial Cable

ER

test description for mobile radio reception tests with am input25
Test Description for Mobile Radio Reception Tests With AM Input
  • Results are contained on a video DVD entitled “BPL Interference Test—Briarcliff Manor—August 2004”
    • Audio for one track of the DVD (as identified in menu screen) was derived from the audio cassette recording. This allowed improved audio quality, since the audio cassette was recorded by direct cable connection to the radio receiver, whereas the audio from the camcorder was recorded using the camcorder’s built in microphone. Synchronization of the overlayed audio cassette track with the original video was within about two seconds throughout the video track.
    • Audio on all other tracks came from the camcorder’s built in microphone.