2/14/2005 - Slide 1 FCC Laboratory FCC Lab/TRB/S. Martin NON-PUBLIC / FOR INTERNAL USE ONLY BPL...

2/14/2005 - Slide 1

FCC Laboratory

FCC Lab/TRB/S. Martin

NON-PUBLIC / FOR INTERNAL USE ONLY


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

2/14/2005 - Slide 2

FCC Laboratory




Outline

• Introduction

• Compliance with Emission Limits

• BPL Notching

• Interference Potential to Mobile Radio in Un-Notched Bands

2/14/2005 - Slide 3

FCC Laboratory




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.

2/14/2005 - Slide 4

FCC Laboratory




Frequency Allocations of the BPL System

• 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

0 10 20 30 40

AMATEURBANDS

UnnotchedMobile Test

ComplainantBand

BPLBPLBPL BPL BPL BPL

FREQUENCY (MHZ)

Notched Band

2/14/2005 - Slide 5

FCC Laboratory




Briarcliff Manor BPL Deployment

9 overhead BPL devices

3 “customers” + 1 traffic camera:

• 2 ConEd employee residences

• 1 Police station computer

Backhaul

Trafficcamera

Relevant BPL device bands

14.4 – 16.3 MHz

19 – 22.8 MHz

1 mile(1.6 km)

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FCC Laboratory




Compliance withEmission Limits

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FCC Laboratory




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

1.8 MHzHigh-Pass Filter

44 MHzLow-Pass Filter

SpectrumAnalyzer

Passive Filters

Agilent E7405AS/N US41160309

Sierra Electronic CorpModel 18444

Dunestar 400HPF

Active loop antennaETS LindgrenModel 6507S/N 1500

2/14/2005 - Slide 8

FCC Laboratory




Compliance with Emission Limits

• 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

BPL COUPLER

LOOP ANTENNA

2/14/2005 - Slide 9

FCC Laboratory





15

20

25

30

35

40

45

50

14 14.5 15 15.5 16 16.5

Frequency (MHz)

Mea

sure

d F

ield

Str

eng

th (

dB

uV

/m)

Extrapolated Emission Limit

QP

Average

QP

QP

2/14/2005 - Slide 10

FCC Laboratory





15

20

25

30

35

40

45

50

55

14 14.5 15 15.5 16 16.5

Frequency (MHz)

Me

as

ure

d F

ield

Str

en

gth

(d

Bu

V/m

)

Max Pk Hold

Extrapolated Emission Limit

QP

Average

2/14/2005 - Slide 11

FCC Laboratory




BPL Notching

2/14/2005 - Slide 12

FCC Laboratory




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

1.8 MHzHigh-Pass Filter

44 MHzLow-Pass Filter

SpectrumAnalyzer

Passive Filters

Agilent E7405AS/N US41160309

Sierra Electronic CorpModel 18444

Dunestar 400HPF

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

2/14/2005 - Slide 13

FCC Laboratory




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

2/14/2005 - Slide 14

FCC Laboratory




Interference Potentialto Mobile Radio

in Un-Notched Bands

2/14/2005 - Slide 15

FCC Laboratory




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 mAntenna center height – 3 m

2/14/2005 - Slide 16

FCC Laboratory




Test Description for Mobile RadioSignal Strength Measurements

• 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

ICOM ReceiverModel R-8500

S/N 1201

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.

Garmin GPS-VGPR Receiver

GPS antenna magnetically

mounted to top of minivan

Dell Laptop ComputerModel PP02X

running on battery

USB-to-SerialConverter

2/14/2005 - Slide 17

FCC Laboratory




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

BPL devices:In-band (19 – 22.8 MHz)

Out-of-band (14.4 – 16.3 MHz)

Signal Strength(dBm)

3 m

iles

(4.8

km

)

2/14/2005 - Slide 18

FCC Laboratory





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



BPL Audibility Bounds:AM at 21.2 MHz

Signal Strength(dBm) 2

mile

s(3

.2 k

m)

2/14/2005 - Slide 19

FCC Laboratory




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

)




2/14/2005 - Slide 20

FCC Laboratory





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




Signal Strength(dBm)

POINT A

1 mile(1.6 km)

2/14/2005 - Slide 21

FCC Laboratory




-110

-100

-90

-80

-70

-60

-50

-2000 -1000 0 1000 2000 3000

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

Sig

na

l S

tre

ng

th (

dB

m i

n 5

.5 k

Hz

ba

nd

wid

th) Run 7 (Selected Portion)

Run 8/17/04b (Selected Portion)

In-Band BPL Device

Road Changes

Pleasantville Rd N State Rd

N S

tate

Rd

Wo

od

sid

e A

v, O

ld S

aw

Mill

Riv

er

Rd

, P

ark

Rd

, S

taff

ord

Rd

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)

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FCC Laboratory




Mobile Radio Received Signal Strength at 21.2 MHzVersus Distance from Nearest In-Band BPL Device

-120

-110

-100

-90

-80

-70

-60

-50

-40

0 1000 2000 3000 4000 5000 6000

Distance to Closest In-Band BPL Device (meters)

Sig

nal

Str

en

gth

(d

Bm

in

5.5

kH

z b

an

dw

idth

)

Run 8-17-04b

Run 7

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.

2/14/2005 - Slide 23

FCC Laboratory




Mobile Radio Received Signal Strength at 21.2 MHzVersus Distance from Nearest In-Band BPL Device

-110

-100

-90

-80

-70

-60

-50

-40

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Distance to Closest In-Band BPL Device (meters)

Sig

na

l S

tre

ng

th (

dB

m i

n 5

.5 k

Hz

ba

nd

wid

th)

Run 8-17-04b

Run 7

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.

2/14/2005 - Slide 24

FCC Laboratory




Test Description for Mobile Radio Reception Tests With AM Input

• 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

ICOM ReceiverModel R-8500

S/N 1201

GarminGPS-V

Receiver

GPS antenna magnetically

mounted to top of minivan

Dell Laptop Computer Model

PP02X running on battery

USB-to-SerialConverter

15 or 20-meter whip antenna (from Iron Horse IHF-5S HF

Mobile Antenna Kit)--magnetically mounted to top of minivan. MiniDV Video

Camcorder

(Sony DCR-PC100)Sierra 145,Directional

CouplerS/N 624

Audio CassetteRecorder

w/voice recording

Agilent E4437BSignal

GeneratorS/N

US41311043

50-ohmTerm

6-dBAtten

EI

ER Serial Cable

2/14/2005 - Slide 25

FCC Laboratory




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.

2/14/2005 - Slide 1 FCC Laboratory FCC Lab/TRB/S. Martin NON-PUBLIC / FOR INTERNAL USE ONLY BPL...

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