LAPLACE INSTRUMENTS RF300 Mk II-A User manual

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LAPLACEINSTRUMENTS LTD
RF300
Large Loop Antenna
(Van Leen Loop)
2metre diameter
Mk II-A
USER MANUAL
Ver2.00 October2011
Serialnumber: XXXX

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Index
1.0Introduction
2.0Packing List
3.0Assembly
4.0Calibration loop
5.0Calibration
6.0Operation
Appendix
A.Calibration data
B.Latest changestostandards
CISPR15 &CISPR16.

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1.0 Introduction
TheRF300largeloop antennahas been developed tomeetthe
requirementsof EN55015:2006 +A2:2009,section 9.9.1,which
referstoCISPR16-1-4:2007 +A1:2008section 4.6.1.Thisspecifies
thelimitsfor magneticfield induced current for luminaireswith lamp
operating frequenciesin excess of 100Hz.
Construction oftheRF300 isas detailedin annex Cof EN55016.This
antennaisfullycompliant with thestandard and detailsof the
calibration factorsare includedin this manual.Theseantennafactors
should beadded totheresultstoobtain correctmeasurementsthat
can becompared directly with thelimits.
Testsetup andlimitsshouldbeconducted as required by EN55015,
section 4.4.
Thedesign of theRF300 issuch thatit can bereadilyerected and
providearigid andstableconfigurationfor accurateand repeatable
measurements.
Acalibrationloop (RF300C)isavailableas an option ifon-site
calibrationisdeemed necessary.TheRF300Callowsthecalibration
loop tobeused onall three axesand rotated within eachas required
by thestandards.

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2.0 PackingList
On receipt of theRF300,check thecontentsof thepackagesagainstthe
diagram shown infig 1.
Identifyeach component and check for shortages.
Qty4
Corner
posts
Qty3loops
Qty4Baseextensions
Qty3Loop
transducers
Switchunit
withcable
Central
pillar
Qty2
tiewraps
10dB
attenuator
Qty1
5mcable
Qty3
loop
leads
Qty31 Grip
Screwsand
qty31 grip nuts
Qty2PlateA
Qty2PlateB
Qty4
PlateC
Qty8
PlateD
Qty4
Saddle clips
Qty8M6x12 screws
Qty8M6nuts
Qty4
Corner
posts
Qty3loops
Qty4Baseextensions
Qty3Loop
transducers
Switchunit
withcable
Central
pillar
Qty2
tiewraps
10dB
attenuator
Qty1
5mcable
Qty3
loop
leads
Qty31 Grip
Screwsand
qty31 grip nuts
Qty2PlateA
Qty2PlateB
Qty4
PlateC
Qty8
PlateD
Qty4
Saddle clips
Qty8M6x12 screws
Qty8M6nuts

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Quantity Item
2 PlatesA
2 PlatesB
4 PlatesC
8 PlatesD
3 Loop antennas (Blue)
4 Corner posts
4Baseextensions
1 Centralpillar
4 SaddleClips
31 Grip screws(M10)
31 Grip nuts(M10)
8 M6x 12 screwsand nuts
3 Loop transducers(current sensors)
1 SwitchUnit
1 ShortBNC—BNC cable,patch cable
1 BNC—BNCcable(5m), outputcable
3 BNC—BNCcable(1.5m), loopleads
1 10dBattenuator
2 Tiewraps

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3.0 Assembly
3.1Stage1Centralsub-assembly
Establishaclearareawith alevelfloor clearof metallicstructuresand
having a3m clearanceheight.
1(a)….Secure PlatesAto
thecentralpillarusing the
supplied grip screws..
Notethattheplateshave
tapered holestomach the
taper on thegrip screws,
soensure thatthese
platesare assembled
correctway round.
1(b)….Secure PlatesBas
shown in fig 3.
1(c)…..Placethecentralpostassemblyin the
centre of theprepared areaand add the4base
extensions,eachusing 2grip screws.
Central pillar
Plates A
Central pillar
Plates A
PlatesBPlatesB
Horizontalstrut
Repeatin4places
Figure 2
Figure 3
Figure 4

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3.2Stage2Corner postassembly
2(a)….Add plateCtothebaseof eachcorner
postusing 2grip screws.Repeatfor theother
corner posts.Notethattheplateisfitted on the
oppositesidetothe2mounting holesatthetop
of thepost.
2(b)….Add the2Plates
Dtoeach corner post
as shown. InFig 6.
2(c.)…..Secure thecorner poststothe
outer end of each baseextension.
PlateC
Corner
post
PlateC
Corner
post
Plates DPlates D
Joinpoststo
horizontalstruts
Joinpoststo
horizontalstruts
Figure 5
Figure 6
Figure 7

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3.3Assemblyof Loops
Theframeshould now look likethat
shown in Figure 8.
Thenextstepsare toadd theloops.
3.3(a)Theconfiguration of theseloopsisas shown in fig9and fig 10.
Theconnectorson each end of theloopare mated with thesocketseither
sideof each looptransducer.Theretaining ring oneach connector needs
tobescrewed firmly tothesocketbut takecare.Theseringswillbind
and bedifficulttoturn unless theloop isaligned properly.Forceisnot
necessary,simplejiggletheloop intoalignmentandthering willturn
easily.
Figure 8
Figure 9

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3.3(b) Installthefirstloop on thestand. Thisisthehorizontal
orientation.Thistask requiresatleast2persons.
Theloop will simplyrestin theslotsatthetop of thecorner posts.Locate
thecurrent transducer closetooneof thecorner posts.Itwill befound
thatif theloop doesnotlieflat,byrotating it relativetothestand,and/
or inverting it,an optimum position can befound whichresultsin the
‘flatest’loop.Notethatthere isnorequirement for aperfectly flatloop.
Someverticaldisplacement
round theloop will notaffect
results.
Screw loopsconnectorsinto
transducersockets.Do not
force,adjustalignment to ease
tightening
BNCoutletfor cableto selector
unit
Screw loopsconnectorsinto
transducersockets.Do not
force,adjustalignment to ease
tightening
BNCoutletfor cableto selector
unit
Figure 10
Figure 11

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3.3(c.) Thesecond loop is
now fitted.Figs12 and 13
show thedetails.
Thisloop isfittedinsidethe
first(horizontal) loop,
orientated sothatit fitsin
thelower ‘slot’in thecentral
pillarand isheld by the
saddleclipsatthetop of the
corner posts(fig 13).
Arrangetheloop sothatthe
transducer iswithin20 cm of
thecentralpillar.
Adjustthepositionof the
loop in thesaddleclipsto
givebestcircularshapeof
theloop.
Figure 12
Figure 13
M6x 12 screws
and M6nuts

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3.3(d). Thefinalloop is
now fittedINSIDEtheother
two.See fig 14.
Thisfitsin theupperslotin
thecentralpillarand under
theother verticalloop at
thetop. Again arrangethe
loop sothetransducer is
closetothecentralpillar.
3.3(e). Theloopscan now
beadjusted for bestshape
and position.Generallythe
verticalloopswilltend to
sag intothelower half of
theantenna.Theseare held
up inpositionby using thesaddleclipson each corner posttotakesome
on theweightof theloop. Thetop oftheverticalloopscanbeadjusted
for bestshapeandthetwo loopsfastened together with thetiewrapsas
shown in fig 15.With care,thetiewrapscan beadjustedtoproduce
reasonablecirclesfor each loop.
Notethattheexactshapeisnotcritical. Deviationfrom perfectcirclesis
inevitablebutthishas nosignificanteffecton antennaperformance.
EN55015 statesin section 7.2that
even theposition oftheUUTinthe
antennaisnotcritical.
Figure 14
Figure 15
Arrangement attopof loops.
Use2tywraps inseriesforadequate
length.

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3.4 MountingtheEUT
Within theloop, constructawooden stand or tabletosuittheproductsto
betested. Thisisnotincluded with theRF300 becauseit needstobe
matchedtoindividualcustomersrequirements.Thestandshould hold
theproductroughlycentralwithin theloop.
3.5 Connections
Connectthelooptransducerstotheswitchunitas shown in fig16.The3
transducer cablesare identifiedby having thick RF absorber filtersalong
theirlength. Fitthecablessothatthesefiltersare nearesttotheswitch
unit.
Theswitch unitisintended for floor mounting,or may bemounted on a
suitabletableifpreferred. Theshortco-ax cableactsasapatch cableto
switch eachinput,oneatatime,totheoutput.
Theoutput fromtheswitchunit isconnected directtotheanalyser or
receiver.
4.0 4.0
Toanalyser
Horiz
(X) Vert
(Y) Vert
(Z)
Looptransducers
Ferriteabsorbersare
atthisendof cables
Selectloop
usinglinkcable
Toanalyser
Horiz
(X) Vert
(Y) Vert
(Z)
Looptransducers
Ferriteabsorbersare
atthisendof cables
Selectloop
usinglinkcable
Figure 16

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4.0 Calibration loop(RF300C)
TheRF300Ccalibration loop ismanufactured tocomply withCISPR16.
Fulldetailsoftheuseof thisloop are provided inthisstandard.
Thisitem(RF300C)isavailableas aseparateoption togowith theRF300
LLA. TheRF300 issupplied fullycalibrated but thecalibration loop is
availabletothosewhowish tocheck thecalibration atregularintervals,
and toensure thatthecalibrationisnotaffected by theenvironment.
4.1Shipping list
Maintable Loop
antenna
Qty4Legs
Washer Vertical
adaptor
Central
pillar
Grip
screw
5mBNC–BNC cable
Maintable Loop
antenna
Qty4Legs
Washer Vertical
adaptor
Central
pillar
Grip
screw
5mBNC–BNC cable
Quantity Item
1 Main table
4 Legs
1 Centralpillar
1 Loop antenna
1 Washer
1 Vertical
adaptor
1 Grip screw
1 5m BNC—BNC
calble
Figure 17

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4.2 Assembly
Mount thetableonthe4legs.Thesejustslot
intotherecess on theundersideof thetable.
Locatethetablein thecentre of theRF300,
with thecentre in linewith thecentralpillarof
theLLA.
Slotthecentralpillarof thecalibratrion
assembly intotheholein thecentre of the
table.
Theassembly
should now beas
shown in fig 19
Figure 18
Figure 19

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4.3(a)Horizontalaxis
Locatethewasher
over thetop spigot
on thecenralpillar,
then locatetheloop
antennaonthistop
spigot.
4.3(b) Verticalaxis
Locatethevertical
adaptor over thetop
spigot.
Add thewasher tothe
horizontalstub, then the
loop antenna.
Retain both itemswith
thegrip screw.
Thecalibration antenna
can berotated tocheck
theseveralanglesas
required by the
standard,andthewhole
top assembly rotated
through 90 degreesto
reposition totheother
verticalaxis.
Figure 20
Figure 21

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5.0 Calibration
Thecalibration techniqueisfullydescribed in CISPR16.Itrequiresthe
useof asignalgenerator covering therange9KHzto30MHzwith a
50ohm output thatiscalibrated for 1v rmsemf.
See appendix A
Thecalibration datafor each loop isvirtuallyidentical. Thefollowing
detailstherefore apply toall three axes,although fulldatafor each axisis
given in theappendix.
For reference,the‘ideal’curveisshownin graph 1.Thisistaken directly
from EN55016,annex C,Figure C8.
Theantennafactor datafor theRF300 are alsogiven.
This‘antennafactor’correction dataeffectively convertstheoutput from
theRF300 (measured in dBuV)directlytodBuA.
Thedatacanbeused withany analyser or receiver capableof EMC
measurements.
Theestimated measurement uncertainty is3dB.
For adetailedexplanation ofthecalibration of theRF300 and discussion
of changestoCISPR15 (EN55015)and CISPR16,see appendix B
If using theSA1002or SA3000 analyser:
TheRF300islistedunder thenormalInputsmenu. Justselectthis
deviceand thesoftware automaticallyappliestheappropriatecorrection
factorssothatthetracereadscorrectly in dBuAandcan becompared
directly with theEN55015 limits.
Further detailsare given in section6.1

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6.0 Operation
Detailsofthemeasurementsand limitsare given in EN55015,section
4.4.Acopy ofthis should beconsultedif performing compliancetests.
TheUUTshould bemounted on awooden frameor tableinthecentre of
theantenna.Thepositionisnotcritical.
Connecting cablestotheEUTshould leavethevolumeenclosed by the
loopsin such awayas tobekept away from theloopstoavoid capacitive
coupling. See Fig C6in CISPR16.
Each axis(loop) should bemeasured in turn. Each should meetthe
requirementsof thestandard.Theloopsare individually selected by
connectingtheshortpatch leadtotheappropriateinputsocketas shown
in fig 11.
6.1 Measurementwith theSA1002 or SA3000 andEMCEngineer
Windows software.
1.SelecttheRF300 item under theinput menu. Theverticalscalewill
indicateunitsofdBuA. (If thisitemisnotavailable,you need alater
version of thesoftware.Contactyoursupplier)
2Under thelimitsmenu, selecttheEN55015 .........2m loop antenna
limit line.
3.Connecttheswitch unit totheanalyser input.
4.With theUUTswitched off,checkthebackground signallevel. At
frequenciesbelow 1MHz,thebackground can bevery strong. Ifstrong
signalsdoexist, check thattheanalyserisnotin compression by
changing theinputattenuator setting on theanalyser and comparing
scans.Apartfrom thebaseline,thetracesshould overlay.If this
happensthen itisOK tousetheanalyser with thatattenuator setting.If
not, increasetheattenuation and tryagain.
5.If thebackground isstrong, it isadvisabletoeither finda‘quieter’
location or screen theroom.
6.Switch theUUTon. Checkthelevelsof signalover thebackground
levelsusing thetechniquesused for conventionalradiatedtesting as
described in theuserguide.
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and canbecompared directly with thelimit lines.
7.ALWAYScheck forcompression (overload) whentaking
measurements.Theamplitudeof thereadingon thescreen cannotbe
used directly as aguidefor compression becausethereadingshavebeen
adjusted for theRF300 characteristics.
If itissuspectedthatthesignalsare toostrong even with theattenuator
switchedin, installthe10dBattenuator in theinput lead totheswitch
unit.Thisadditionalattenuator canbeautomatically compensated for in
thesoftware by adjusting thepre-amp settingson thescreen.
8.If thebackground and theproductis‘quiet’,and especially at
frequenciesabove20MHz,use0dBattenuation.
10dBattenuator
Figure 22