theRSGB @theRSGB

vision valuesgovernance teamwork

EMC– DiagnosingandReportingRFI

of Great Britain

Advancing amateur radio since 1913

Radio Society

Dr John Rogers, M0JAV Chairman EMC Committee

theRSGB @theRSGB

WhatcausesRFI?

theRSGB @theRSGB

WhyisRFIaproblem?• Allelectricaldevicesproduceelectromagneticemissions conducted &/orradiated

• Differentelectricaldevicescanbemoreorlessimmune tointerference

• Problemsarisewhenemissionlevelsarehighenoughtoeffectoperationofotherequipment

• Emission andImmunity standardsaredesignedtoallowdevicestooperatetogether

• RadioamateursandSWLsrelyonlowbackgroundnoiseforgoodradioreception

theRSGB @theRSGB

EMRadioFrequencyInterference(RFI)

theRSGB @theRSGB

WhatServicesdoesEMCCprovide• AdviceandSupport

– HelpandadvisememberswithRFIproblems• EMCMattersForumandproblemreporting• RSGBwebsiteself-diagnosisusingEMCleaflets

– Provideupdatesthroughwebpagesandpublications• RegularEMCcolumninRadcom – “EMCMatters”

• ProtecttheSpectrumfromRFI– RepresentationonStandardsCommittees– Lobbyingregulators,suppliersandserviceproviders– InvestigationsofNewTechnologyInterference– Recommendationsfornewthreats

theRSGB @theRSGB

RSGBEMCCServiceChanges• HelpDeskandEMCMattersForum

– EMCMattersForumvisited93000timessinceApril2015– Leafletsandpublicationsupdatedaimedatselfhelp– HelpDesk- Over100reportsperannum- viaemailandtelephone– Onlineproblemreportinghelpsuslobbyingsuppliersandregulators

• NewprocessforInvestigatingRFIproblemsusing– Assisteddiagnosisusingsignatureexamples– spectra,waterfalls,recordings– Helpsyoufindwhere itis,when itisoperatingand whatitis

• Ofcom adviceandassistance– ReluctanttoenforceagainstnonWTAapparatus– NewStatutoryInstrumenttocoverinserviceequipment– RSGBpreparingreportsonresultsofinvestigations

theRSGB @theRSGB

HelpDesk,ForumandReportingTypeofRFI Number

ofcasesNumberresolved

Comment

VDSL 105 5 Linebalanceandextension fix

PlasmaTV 30 26 PanasonicandSamsungsetsreplaced

SolarPV 18 4 Problem usuallyOptimisersorInvertorscanbeaffected bywiringlayout

SMPSU 11 9 Probablymostcommonsourcemostpeopleidentifyproblemanddon’treportit

Homeappliances 8 4 Fridges,Boilers,Alarms

LEDLighting 5 3 MostOKsomebadfloodlightsand12Vonesoftenaproblem

Pylons,Industrialetc 9 5 Outstandingwindfarmproblems

Breakthrough 9 3 Telephones,POS,HiFi,TVdistributionamps

theRSGB @theRSGB

Involve Outsiders?

Liaise with Supplier to

alleviate problem

Problem Resolved ?

Assign an RSGB

Investigator

Record Outcome Lessons Learned, update signature database, Close Case

Yes

Yes No

No

Yes

Problem referred to RSGB from Ofcom

Interference Problem reported to RSGB via phone, forum or online

report

Assign an Advisor Case # Assigned

Request Basic Information

Frequency, Type, Location, Times

Identify class of interference

and collect signature

Compare with other similar cases

to identify common items

Diagnose type and collect

further characteristics

Locate source and record times

active

Record signatures prepare

full report

Signatures Logsheets

Evidence of Harmful

Interference Location Records

Ofcom accept case and follow

standard process

New Investigations Process

Problem recorded on standard form Advisor assigned to assist

Likely source DiagnosedLocatedRecorded

If cannot be resolved locallythen collate cases to approach Ofcom or Supplier

Investigate further and recordHarmful Interference

Log to show Degradation, Obstruction or Repeated Interruption

Steps to reduce Interference

theRSGB @theRSGB

RFISignaturesseeEMC04• Narrowband afewspotfrequencies,onanSSBreceiver,atrue

narrowbandsourcewouldbeheardasatone,butinsomecasesitwillbearoughburblingsignalcoveringafewkHz

• Broadbandwithnopeaksappearsrightacrossabandataboutthesamelevelwithnopeaks

• Broadbandwithbroadpeaksfromswitch-modepowersupplies/digitalelectronicsproducebroadbandemissionswithregularlyspacedbroadpeaksatfundamentalfrequency

• Broadbandwithnarrowpeaksdigitalelectroniccircuitry• Driftmeasurethetimeperioditgivesaclue• Modulation50or100Hzbuzzmainssynchronous– SMPSU• WhitenoiseoftenxDSL• Sigidwiki.com containssignaturesofknownsystemsandsome

unknownsandinterference;wecouldaddtothisordevelopsimilar

theRSGB @theRSGB

Interference Problem reported via phone,

forum or online report

Assign an Advisor Case # Assigned

Request Basic Information

Frequency, Type, Location, Times

Broadband No Peaks

peaks

Harmonic Peaks

Narrowband

N

No

No

xDSL

Electric Motor

Ignition System

Arc / Spark

Yes

SMPSU

Solar Invertor

CFL / LED

PLT

No

No

No

No

No

No

No

Crystal

Alarm

Radar

Yes

yes

Electric Fence

No

No

No

Guidance note Provided1) In each case a spectralPlot / Waterfall is providedtogether with a video / soundclip giving the device signature.2) A standard form to record the device fingerprint and other useful information is supplied.3) Possible Cures are suggested.

4) Advise on how to locate the source and how to approach and work with ownerLeaflet provided, Standard form used to record location, characteristics & times

Involve Outsiders?

Involve Supplier?Involve Ofcom?

Problem Resolved ?

Assign an Investigator

Record Outcome Lessons Learned, update signature database, Close Case

Yes

Yes No

No

Yes

Plasma

No

Comparison with Signature sheets to identify likely sourceCorrelation used to confirm some sources

Guidance notes on what to look for

Linked to advice leaflets for minimising impact

Record actual Signature to add to database

theRSGB @theRSGB

• Frequenciestocheck• Whattolookforandrecord;bestreceiversetupstouse• Timeprofileofinterference

RFI Signature Sheets - VDSL Upstream 2

theRSGB @theRSGB

VDSLduringTraining

11/10/201412

Carriers4kHzapart

Carriersacrossupstreamanddownstreambands

theRSGB @theRSGB

ComputerSMPSU10to18MHz

theRSGB @theRSGB

ComputerSMPSU19to27MHz

theRSGB @theRSGB

LeadAcidBatteryCharger

theRSGB @theRSGB

LEDlighting

theRSGB @theRSGB

SolarPVSpectra

• Mitigation– DCcablesshouldberunascloselyspacedpairs– Clip-onferritesmayberequiredonDCcables– Maybenecessarytochangeinverteroroptimisers

11/10/201417

Broad band emissions up to 40dB above typical back-ground noise level on 10.1 –10.15 MHz band

theRSGB @theRSGB

PlasmaTV• Problems may

increase as the plasma ages

• Cooperation of the set owner is key as suppliers will only deal with them

• Problem will go away as sets go out of production

• “yourequipmentshallnotcauseinterference…”notenforcedbyOfcomorBBC• Contact Ken Underwood G3SDW directly or via the EMC Matters forum he

has good record with manufacturers getting problems resolved particularly with Panasonic and Samsung

theRSGB @theRSGB

FluorescentLighting

Starter and electronic ballast cause the problemGood Earth at RF, screening and ferrites on leads to ballast helpFilter the shack supply to reduce conducted emissions

theRSGB @theRSGB

FaultyCHPump

Carriers every 15kHz modulated with water flow

theRSGB @theRSGB

Thisiswhereyoucanhelpus!!!• HowmanyofyouhaveorcanborrowanSDR?• Howmanyhaveaknownsourceofinterference?• Pleasemakesomespectra/waterfallpicturesorsoundrecordingswecanaddtothedatabase

• Confirmsourcewithon-off-ontest• UseofSpectraandWaterfalldisplays

– Avoidoverloadingthereceiver– gainsettings– Selectfrequencyrange(filtering),resolutionandaveragingsuitableforinterferencetype

– Bewareofcheapdongleswithpoorfilteringwhichgivealiasesofactualsignal

theRSGB @theRSGB

Standards

• InternationalandEuropeanStandardsdesignedtoprotectagainstRFI

• Regulationscanpreventequipmentbeingputonthemarketifnotcompliant

• WTASection54allowsOfcomtomakeRegulationstostoptheuseofapparatusthatiscausingundueinterference

theRSGB @theRSGB

Ofcom:WTAInterference• WTASection4requiresOfcom toprovideadviceandassistancetocomplainantsofInterference

• WTASection54Ofcom canregulateformaximumEMenergythatcanberadiatedandconductedtomains

• Ofcom shouldregulatetoensurethatapparatusdoesnotcauseundueinterferencewithwirelesstelegraphy

• RecentS54regs extendtoapparatusthatisimproperly— (i)installed;(ii)assembled;(iii)maintained;(iv)functioningduetodegradation,deterioration,modification,ordamage;or(v)usedforapurposeotherthanitsintendedpurpose

• Ofcom canthenenforceunderSection55ofWTA

theRSGB @theRSGB

EnforcementOfcom requirements• MustbeevidenceofActualHarmfulInterference

– degrades,obstructsorrepeatedlyinterruptsanythingwhichisbeingbroadcastorotherwisetransmitted...bywirelesstelegraphyandinaccordancewithalicence

– Tighterwhenemergency/safetyservicesimpacted• ApparatusresponsibleisIdentified• Allreasonablestepstominimise impacthavebeentakenbypersonsufferingRFI

• OnbalancePublicInterestisserved– InaBalanced,transparent,proportional,accountableway

theRSGB @theRSGB

HarmfulInterferenceEvidencetocollect

• HereandThere– usetwolocationsonewithInterferenceandoneclosebywithout,usetwoequivalentsetupsandlogatboth– automateifpossible

• NowandThen– keeplogsofcontactswhichwereandwerenotmadebeforetheinterferenceandcontrastwithsituationnow

• Withandwithout– locateandeitherturnoffornulltheinterferencetoshowstationsworkablewhenInterferenceisabsent

• Remember needtodemonstrateactualnotpotentialHarmfulInterference- nogoodjustquotingRFIlevel

theRSGB @theRSGB

UpdateonInvestigations

• xDSL – Investigationsreport(172pages)preparedforRSGB,BT,Ofcom meeting

• SolarPVstillcollectingdataonnoisyunits• LEDLighting– reportstoTradingStandardsondefectiveunits

• Windfarms– AllavenuesexploredbyTom:Ofcom,MP’s,MEP’s,Suppliers,Ombudsman

theRSGB @theRSGB

theRSGB @theRSGB

ThankYouforyourattention

theRSGB @theRSGB

MinimumSignalsdetectablebyAntenna