NASHUA AREA RADIO CLUB

TECH NIGHT – SOFTWARE

DEFINED RADIOSMARCH 8TH,2016

• WhatisanSDR?Whyuseone?• Howdotheywork?• SDRDemo– FlexRadio6000Series• InterfacingToOtherEquipmentandSoftware

• Amps,BandDecoders,etc.• Loggers,CWandDigitalModeswithSDRs

• SDRDongleDemo– Aninexpensivewaytogetstarted

• SDRAdd-onforConventionalRadios

SoftwareDefinedRadios(SDRs)

Topicsfordiscussion

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SoftwareDefinedRadios

Examples

ManyHardwareOptions ManySoftwareOptions3

TheComputerRevolution

• Off-lineapplications– Calculators– Logbooks

• “User-definedRadio”– e.g.,HTmemoryandmodeuploads

• “User-controlledRadio”– Readstatusfromrig– Read/write (statusandcontrol)– e.g.,HamRadioDeluxe,CT,N1MM,RoverLog, …

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MoreComputerRevolution

• DigitalSignalProcessing– Filters– PSK,RTTYdemodulators– Skimmers

• “Software-DefinedRadio”– Allnonfrequency-determining processes

doneaslogicorequations

“There is a distinct difference between a radio that internally uses software for some of its functions and a radio that can be completely redefined in the field through modification of software. The latter is a software-defined radio.”

AC5OG (now K5SDR), QEX Jul/Aug 2002

MOST

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SoftwareDefinedRadioWhat’sItBuyMe?

• Moreidealfunction– Betterperformance

• Expandedfunctionalcapability– Was:selectable.Now:continuouslyvariable– Was:sweptdisplay.Now:continuousdisplay

• ImprovedSituationAwareness– Understandwhatisonabandandwhereitis

• Updatesequalnewcapability– Newmodes– Newfiltertypese.g.,TrackingNotchFilters

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SituationAwarenessIntegratedBandscopesofthe2000s

• “Nearreal-time”style• Swept“secondaryreceiver”

• Displaysareaaroundtunedfrequency– ± 12.5/25/50/100kHz

• Mediumresolution• Sweptatmoderaterate

IcomIC-756PRO

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SituationAwarenessDigitalSampling/Processing/Display

• Goal:continuous,real-timedisplay

• PhysicalaccessoryorsoftwareGUI

• Stillcaptures“IF”spectrum

8ElecraftK3andP3Panadapter

SituationAwareness- SDRDigitalSampling/Processing/Display

• Continuous,real-timedisplayviaFouriertransformofentire“IF”bandwidth

• Highresolution– Inbothfrequencyandtime

• Waterfallprovidesactivityhistory• Adjustableintensity

– “VisualEnhancement” allowspullingsignalsoutofthenoise

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SoftwareDefinedRadioArchitectureVariants

RFDown-

Convert,Detect

SoundCard Software

RF Down-convert

D/AConvert Software

RF Down-convert

D/AConvert Software

SingleConversionDesigns

Flex-3000,Flex-5000,ApacheLabs,RFSPACE,

Dongles

RF D/AConvert Software PC

Client

RF D/AConvert Software Buttons

& Knobs

DirectSamplingDesigns

Flex-6000Series,IcomIC-7300

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BasebandAudio

Firewire

Ethernet

It’saBlackBox(notreally)

• What’sinthere?(hardware)– RFinput-output switching– Filtering– LOandfrequencyselection– A-DandD-Aconversion– Computer interface

• Where’stherest?(software,that’swhere)– Firmwareinthebox– Drivers toconnect theboxtothecomputer

viaFireWire(IEEE1394),USBorEthernet– Softwareapplicationorclientprogramincomputerperforms“radio”

and“knobs”functions

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FlexRadio 6000SeriesDirectConversionArchitecture

FlexInsiderAugust2012

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WhyAllThatMath?

• Adiodedetects

• Butarealdiodeisn’tperfect

• Themathdescribeswhat’ssupposedtogoonVo=0,(Vi<1)Vo=1,(Vi>=1)

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What’sThisI/QThing?

• IandQbothsampleincomingsignals

• QChannel isshifted90o fromIchannel

• Effectivelyseparatesfrequencies aboveandbelowLO

• Doublesradio“passband”foragivensampling rate

• Makessideband“demodulation “asnap

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Filtering intheDigitalDomain

• SimplestdesignisFiniteImpulseResponse orFIR

• Implemented byaddedscaled&delayedversionsofasignal

• Softwareapplicationsexisttodetermine coefficients

• Withtoday’sdigitalprocessors, digitalfilterscanbeverycloseto“ideal”

– Roll-off”sharpness”– Passbandripple– Phaseshift

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SoftwareDefinedRadiosKeyElementsEffectingPerformance

• Architecture– Minimizeuseofanalogcomponents– SingleConversionvs.DirectSampling

• A/DConverterResolution,RangingandSpeed– 12-bit,16-bit,24-bit,….Resolution– Converter rangingalgorithms– Samplingspeed determines radio“bandwidth”– PanadapterBandwidth (96KHz– 14MHz)

• PrecisionandAccuracyofDigitalClock– Stable,temperature compensated clocks– Determines phasenoiseperformance– GPSDisciplinedOscillatorsorGPSDO’s(especially forUHFandabove)

• Processingpowerin“box”– NumberofsimultaneousPanadpaters (1– 8)andreceivers

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SoftwareDefinedRadiosInterfaceBetweenthe“Box”andthe“Computer”

• Informationontheinterfacecaninclude:– I/Qdigitaldatastreams– Radiocontrolinterface (e.x.CATInterface)

• Interfacespeedcanlimitpanadapterbandwidthinmanydirectcoversiondesigns

• NativeinterfacesupportonPCishighlydesirable• Thin-clientdesignsusingethernetmaybea“sweetspot”

Interface Bandwidth Distance Remotable?

Availability on

RecentPCs

Analog Audio ~1.5Mbps Few Feet No Sound cardusingI/Q

Firewire 400– 800Mbps FewFeet No Not native

Ethernet 100Mbps– 1Gbps

WorldwideviaInternet

Excellent Native

USB3.0 Upto5Gbps FewFeet No Native

PCInternal Limitedbybus Same Box No CustomPC

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RemoteOperatingWithAnSDROfficeDesktop

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Flex-6700SDROperationDemoScenarios

• PhoneQSO

• MultiplePanadapters(“slices”andreceivers)

• TrackingNotchFilters

• CWQSO

• DigitalQSO

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Flex-6700

SDR

PCRunning

SmartSDR

Remotevia

theInternet

Flex-6700 inOperationPhoneQSOs,SplitOperation,MultiplePanadapters,Filters

USPhoneQSOon20m 5J0PDXpedition SplitQSO

Multiple PanadaptersandReceivers21

TrackingNotchFilter(TNF)

Flex-6700 inOperationCWQSOs,CWSkimmer,DigitalQSO

2015CWSweepstakes Contest

VK9WADXpedition Pileupon30mCW22

DigitalDXQSO

PAPort A Port

A1-6

BandData,PTT&INH

PTT&INH

TomicroHAMControlBus

ToAntennaSwitching

1GBpsSwitchedLANWAN GW

(100/5

MBps)

WiFi GW

802.11g/n

microHAMSNDBandDecoder

Flex-6700SDR

FlexRadioMaestro

HeilPR781/USBQ

BoseBluetoothHeadset

ShackRemote

Site

SoftwareAppsRemote:• RotatorControl• Power/SWRMeter• Amp/TunerControl• AntennaSelection (custom)

LANRemotes Audio,CW,CAT,UIandCOMPorts

ElecraftW2Power/SWRMeter

LocalaudioviaPC

Elecraft500WAmp&Tuner

FilterMaxBPF

SoftwareDefinedRadiosInterfacingtotheOtherEquipment

DDUtil Creates

PhysicalCAT

Interface

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PTT&INH

Flex-6700SDR

LocalaudioviaPC

CWOperationCWSkimmer

LANCarriesAudio,CW,AT,UIandCOMPorts

VirtualAudioCableReceive I/QStream

DAX(Digital

AudioExchange)

SDR-Bridge

ConnectsDAX

andCWSkimmer

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PTT&INH

Flex-6700SDR

LocalaudioviaPC

DigitalOperationandLoggerInterfaceDXLabSuite

LANCarriesAudio,CW,AT,UIandCOMPorts VirtualAudioCable

Tx&RxAudioStream

DAX(Digital

AudioExchange)

SDR-Bridge

ConnectsDAX

andCWSkimmer

25VirtualCATCable

DXLabCommander

DXLabWinWarbler

RTL-SDRDongleOperationDemoScenarios

• OverviewoftheHardwareandSoftware– RTL-SDRDongleandAntennaPackage– HaminUpUpconverter– SDR-RadioSoftware

• ReceiveFMBroadcastRadio• 2mSimplexFM• 2mRepeaterMonitoring• WeatherBandRadio• PagerChannelReception• …

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Setupguide- http://www.rtl-sdr.com

SDRAdd-onforConventionalRadiosExample- RFSPACESDR-IQ

• SDRConnectstoIFoutputofconventionalradio• UseSDR-RADIOsoftwaretodisplayIFinSDRformaton

computer• SDR-RADIOusesCATinterfacetotuneconventionalradio

baseduponSDRinputs27

IFOutput

USBIQ+Control

AdditionalTopicsforDiscussion

• OpenSourceSDRProgramsavailable

• NewIcomIC-7300DirectSamplingRadio

• ContestingPossibilitieswithSDRs

• AdvancedDigitalModeswithSmartSDR

• SDRPerformanceMeasurementsReciprocalMixingDynamicRange(RMDR)andPhaseNoise

• …

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2:00,5:00,8:45,12:30,28:15mins

UsefulLinks

• FlexRadio- http://www.flexradio.com/amateur-products/

• RTL-SDR- http://www.rtl-sdr.com

• RFSPACE- http://www.rfspace.com

• SDR-RADIO- http://sdr-radio.com

• SignalIDWiki- http://www.sigidwiki.com

• SherwoodRadioPerformanceComparisons-http://www.sherweng.com/table.html

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