Sequerra 1 User manual

CONTENTS
President'sLetter
GuaranteeCertificate
Two WarrantyRegistrationCertificates
CertificateofMeasuredPerformance
Operational Instructions
InstallationInstructions1
Front Illustration2
Immediate Operation3
DescriptionofTunerDisplays.4
Back PanelIllustration, 7
DescriptionofBackJackPanel8
DetailedDescriptionof Scope 11
Graticule andTraceDescriptions13
Simplified TheoryofOperation20
Block Diagram23
Back JackPanel Socket 24
Final TestCheckList
Mounting Template
RepackingInstructions
SparePartsList
SparePartsPacket
5174

THEBEQUERBACO..mc
71-07WOODSIDE AVENUE
WOODSIDE.N.Y.11377
[phone]
Dear Customer:
I wouldliketo take this opportunitytopersonallythankyouforbecomingone
of thediscerningIndividualstoowna Sequerra Model 1 FM Tuner. Thisinstrument
representsa state oftheartachievementintheHiFidelityIndustry,andembodies
in excess of 25,000 hoursofengineering.
When completed,your Model 1 FM Tuner wasIndividuallymeasuredfora
number ofperformancecharacteristics.Themeasurementsaredocumentedona signed
Certificate ofPerformance,bearingtheserialnumberofyourindividual Tuner.
Your Model 1 iscoveredbytheSequerraFive Year Warrantyto meet thestandard
specifications.I wouldliketo callyourattentiontoa numberof exceptions tothe
plan:
1.The Model 1 Tuner mustbepurchasedonlyfroma FranchisedDealer.
2.Anyresale,orgiftofthe Model 1,requiresthefactory'sacceptanceofthe
transferoftheunexpired Warranty.
3.TheCompanyundernoconditionswouldhonora WarrantyIfit does not
meet allofthecriteriasetforthintheWarrantyRegistrationCertificate.
Although theWarrantyisin effect forfiveyears,designandmanufactureof
your Tuner Isaimedata usefullifeofat least tenyears.Shouldyour Model 1 FM
Tuner requireservicing, please contactonlyyourFranchisedDealer,orthefactory
directly, asthecomplexityofdesignrendersitbeyondthemaintenancecapabilities
of theuntrainedserviceman.
Our Companyisdedicatedtothedevelopmentofextremelyhighquality
products,manufacturedinverylimitedquantities.Weanticipatethatourproducts
will alwaysbeinshortsupply,thereforeweoffertoeverypurchaserofthe Model 1
FM Tuner, a preferential status vls-a-vlspurchaseofanyofourfutureproducts,and
weanxiouslysolicityourInspectionofourfutureproducts.Aswithanysmall
engineeringbasedorganization,we welcome suggestions andcriticismsfromour
customers,andhopeto enterintosucha dialoguewithyou.
We feelyour Tuner willprovideyouwithyearsofsatisfyingperformanceand
lookforwardto servingyouagainInthefuture.
f
>\
Richard Sequerra
President
5174

INSTALLATION INSTRUCTIONS
IninstallingtheSequerraModel1 FMTuner,certainprecautionsmustbeobserved.Followthe
InstallationInstructionscarefully,andinsequence.Itisadvisedthatyoufamiliarizeyourselfthor-
oughlywiththepushbuttondisplaysandthebackjackpaneltoappreciatethecapabilitiesofthe
tuner.
Thefollowingpageswillimpartanin-depthunderstanding.Thepageentitled Immediate Oper-
ation explainshowtoquicklyworkyourtuneronceitisproperlyinstalled,withoutthoroughly
understandingit.Buttoappreciatethefullsignificanceoftheperformanceofthetuner,andto
makeallowableadjustmentstoenhancethelisteningquality,a thoroughunderstandingofitsoper-
ationsisimperative.
Warning: Pleasekeepinmindthatthewarrantydoesnotcoverdamagecausedby
misuse,mishandling,insufficientventilation,orexcessivelinevoltage.
Placement - Thetunershouldnotbeplacednearanysourceofheat.Allowa minimumoftwo
inchesclearanceabove,behind,andbelowthetunerforventilation.
Custom Installation — Ifyouareinstallingthetunerinanequipmentcabinet,orbehinda
panel, usethemountingtemplate(nearbackofthismanual)tomaketherequiredholesandcut-
outs.
Antenna — Choosingtheproperantennasystemisessentialinordertominimizemultipath
interference.Signalreflectionsfromsurroundingbuildings,towers,orhillscausemultipathinter-
ference.Thisphenomenon,similarto"ghosts"inTV,producesdistortionintheFMsignalsatthe
antenna. NoFMtunercancompletelyeliminatemultipathinterference,thereforecarefulselection
of anantennaisnecessaryinordertooptimizeperformanceofthesystem.ThebestFMreceptionis
obtainedwitha steerableorrotatableantenna.Thisholdstrueforeitheranindoororoutdooran-
tennausedinconjunctionwitha rotorsystem.A comprehensivediscussionofFMandFMsystem
problems(includingantennas)isavailablefromtheSequerraCompanyinbookletform.Theprice
of $1.00covershandlingandmailing.
Output — Connectthetunertothepre-ampusingthetuner'sOutputFixedjacksontheback
panel. L & R standforleftandright.Besuretoconnectlefttoleft,andrighttoright,fromtuner
topre-amp.
Domestic Units — Makesurethatlocalpowerisnominally120voltsACat60Hzasmarkedon
thetuner'sbackpanel.
Export Units — Powertransformerisadjustedfora lineinputvoltageof220to240volts.A
properslowblowfusehasbeeninstalled.
Power Line — UnwindthepowercordandplugitintoanACwalloutlet.
5174
1

FRONT ILLUSTRATION
For Immediate operation(afterproperlyfollowingInstallationInstructions)employpushbuttons as shown by FunctionArrows In thisIllustration.
5174 2

IMMEDIATEOPERATION
Toimmediatelyoperatethetuner(afteritisproperlyconnectedandpluggedin}withouta
fundamentalunderstandingofthevariouspushbuttonfunctions,simplydepressthelowestright-
handpushbuttonwhichbearstheSequerra"S".Thiswillturntheseton.Turntheknobtotunein
yourdesiredstation.Thestation'sfrequencyappearsonthedigitalreadoutdisplayabovetheword
Megahertz. Anovercapacityoftuningisprovidedwhichpermitsthesettobetunedfrom87.7MHz
through108.3MHz.The Stereo Pilot willbeilluminatedifthetunedstationisbroadcastinga
stereoprogram.Itissuggestedthatthefollowingpushbuttonsbeemployed:
Display: Tuning
Separa tion: Maximum
Dofby.Off
Muting: Inter-Station
Mode :A u tomatic
5174

DESCRIPTIONOFTUNERDISPLAYS
Thetwoverticalrowsofsixpushbuttonseachoperatethefunctionsdescribedontheiradja-
centdisplaywindows.Thearrowswhenlit,pointingtothedisplays,willindicatewhichdisplaysare
functioning.Theupperfourpushbuttonsontheleftareoscilloscopefunctionselectors.Theyare
interdependent,anddepressinganyoneofthefourwillreleaseanyotheroneofthefourwhichwas
previouslydepressed.
Asimilarstructureexistswiththethreemutingpushbuttonsonthetoprightside.Theremain-
ingfivepushbuttonsareindividuallyindependentofanyother,andwhendepressedwillremainso
untilindividuallyreleasedbydepressingThemagain.
Thefollowingdescriptionscoverpushbuttonfunctions.A moredetailedanalysisoftheoscillo-
scope'stracesareexploredlater.
DISPLAY
Theupperpushbutton.Display:Panoramic, displaysallstationsthataretransmitting
1MHzaboveandbelowthetunedfrequency.Theverticalpipsofthescope'strace
representstationswhicharebroadcastinga signalabovetheambientinterstationnoiselevel,which
isthebaseline.Whentunedtoa particularfrequency,thestationyouarelisteningtowillbe cen-
teredonthescope'sgraticule.
DISPLAY
Thesecondpushbuttonontheleft, Display .-Tuning isusedtoproperlytunetheset.
Forpropertuning,thetraceshouldbeadjustedfortheuppercenterofitspath.
DISPLAY
TLTvjtR V1CTCJM Thethirdpushbutton,Display:Tuner
Vector, displaystheaudiocomponentsonan
X-Ybasis.Thisvectorexhibitstheleftandrightstereochannelsalonga perpendic-
ularaxis.Itisusedincheckingtheseparationandphasecharacteristicsofstereoprogrammaterial.
Thewidertheangle,thegreatertheseparation.Thehigherthetrace,thestrongerthesignal.A
verticallineindicatesnoseparation(asa centrallypositionedannouncer,ormonophonictrans-
mission).
C*SPCAY
EXTVI UHJM
Thefourthpushbutton. Display:Ext. Vector, displaysseparationandphasecharac-
teristicsofanystereoorfour-channelprogramming.Tobefunctional,proper con-
nectionshavetobemadetotheExternalVectorInputsectioninthebackpanel.Stereoprogram
materialisdisplayedidenticallytoDisplay:TunerVector.Four-channelprogrammaterialisdis-
playedon4-legsofan"X"shapedtrace,indicatingthecornersoffront,rear,left,right.Thesepara-
tion, phase,andamplitudeofeachlegofquadprogrammingcanbeobserved.
SEPARATION
Thefifthpushbutton,Separation: Maximum-Hi Blend, controlstheseparationofthe
highfrequenciesinstereobroadcasting.Itisusedtoeliminatesomenoiseunder
difficultlisteningconditions.OrdinarilyhaveitsettoMaximumforbestspatialanddirectional
definitionoflisteningmaterial.
5174
4

Whenencounteringexcessiveinterferenceorbackgroundnoise,switchtheSeparationtoHi
Blend. Thispositionblendsthehighfrequenciesoftheleftandrightchannelstogetherprovidinga
goodcompromise,betweenmoderateseparationandmoderatesuppression,ofout-of-phasenoise
anddistortion.Thispermitsyoutomaintainfullfrequencyresponse,differingfromconventional
noisefilterswhicheliminatenoisebyreducinghighfrequencyresponse.Note:IftheHiBlend
positiondoesnotsatisfactorilyreducestereonoise,switchingtheModedisplayfunctionfromAuto-
matictoMono(fourthpushbuttononright)completelyeliminatesallstereonoise,buttheprogram
willbereceivedmonophonically.
Thebottompushbuttonontheleft,Dolby.Off-On, interposesorremovesa Dolby
TypeB decoderintheoutputaudiolines,-affordingyouthebenefitsoftheDolby
noisereductionsystemwhenthestationistransmittingDolby.
Theupperthreepushbuttonsontherightareformutingfunctions.Theyareinterrelatedand
depressinganyonecancelsouttheothertwo.Themutinglevelissetbyanadjustmentontheback
jackpaneloftheset(refertoBackPanelMutingInstructions).
objectionable(withthehighperformanceoftheSequerraTunerthisnoiseappearsaccentuated),it
isusefulingivingyoua truerunderstandingofwhatisreallyhappeningthroughouttheentire
broadcastband.Itpermitsyoutohearbroadcasts,witha veryweaksignalstrength,thatare
beneaththepresetmutinglevel.
MUTING
MUTING
•NTER BllOfO
Thesecondpushbuttondown.Muting:Inter-Station,mutesallundesirednoise
(beneaththepresetmutinglevel)whiletuningbetweenstations.
Thethirdpushbutton.Muting:Inter-Stereo.willmutenotonlyinter-stationnoise
butalsomonophonicbroadcasts,allowingyoutoreceiveonlystereobroadcasts.
Thereisanothermutingsystemdesignedintothetunerwhichisnon-adjustable.(TheMuting
LeveladjustmentisontheBackJackPanel).Ithastodowithoff-centertuningnoise.Tobest
understandit,considertheDisplay:Tuningpattern.Whena stationisproperlytunedthetraceison
thecenterline.Asthetraceapproachesandgoesdownthesidesofthetuningpattern(offcenter
frequency)itisautomaticallymuted.ThismutingcircuitoperateswheneitherInter-Stationor
Inter-Stereomutingisincorporated.Itisby-passedwhenMuting:Offisengaged.
Thefourthpushbuttonontheright. Mode: Automatic-Mono, intheautomaticposi-
tion, automaticallysenseswhetherthereceivedsignalisstereoormono,andchan-
nelsthesignalthroughthepropercircuitry.ConsequentlyitisusuallykeptintheAutomaticposi-
tion. TheStereoPilotwilllightwhena stereoprogramisbeingreceived.Whena monoprogramis
beingreceivedthesetisdesignedtobypassthemultiplexdecodingcircuitry,thuseliminatingany
possiblestereonoise.WiththeModepushbuttondepressedtoMono,itwillreceivestereoprograms
monophonically.Thisisusefulineliminatingallstereonoiseswhenstereoprogrammingisbeing
AUTOMATIC
MODE
5174
b
OOLBV
Depressingthetoppushbutton, Muting.Off, cancelsoutallmutingfunctions.Inthis
modeallinter-stationnoiseisheard.Althoughmostpeoplefindinter-stationnoise

receivedunderdifficultconditions,andtheSeparation:HiBlendpushbuttondoesnotsufficiently
eliminateundesirablenoise.Ofcourse,inthismode,theprogramwillbeheardinmono.
ItisalsosuggestedtohavetheModeinMonowhenlisteningtoa monophonicprogram,to
eliminateanypossibilityofanunwantedsignaltriggeringtheStereoPilot.Thiswoulddirectthe
programmedmaterialthroughthemultiplexdecoder,andconsequentlypickupanyconcommitant
stereonoise.Ifthisoccurs,theStereoPilotwillflickon.
PANEL
DIM
The Panel:Normal-Dim, pushbuttonmerelychangestheintensityoftheillumination
of thedisplayscreensandoscilloscope.
PDWEP
The Power: On pushbuttonswitchesthetuneronandoff.Itismarkedwiththe
Sequerra"S",theonlyidentificationonthefrontoftheset.whichservesforeasily
locatingthepowerbuttonwhenthesetisinits"blackout"position.IntheOnpositionitlightsall
functionaldisplays.
5174
6

BACKJACK PANEL
FOCUSINTENSITY-*A0]USTFORVERY
DIM SPOTONEXTVECTOR
POSITIONWITHNOSIGNAL
SCOPE
VERT. HOR.
CENTERING
25MSEC.
DOLBY
MUTING
LEVEL
DETECTOR
OUTPUT
PANORAMIC SWEEP
WIDTHCENTER
ACCESSORY
FUSE 105-135VAC 50-60 Hz
SERIALNUMBER
L OUTPUT R
FIXED
LEVEL
OUTPUT
EXT.VECTOR
INPUT
FRONT R
LEVEL
REAR
ANTENNA CONNECTION TERMINALS
300 n
75 n
Connect antenna leads toappropriateterminals(matchImpedances) 7
5174

DESCRIPTIONOFBACKJACKPANEL
ThebackJackPanelhasfourinputs,fiveoutputs,anaccessorysocket,scopeandpanadjust-
ments,a Dolbyconverter,a fuse,thelinecord,andtheserialnumber.Followingisa descriptionof
theirproperuse.
Fuse — For U.S.A. a l-amp,slow-blow,standard3AGcartridgetypefuseisused.Fornon-
domesticuse,theproperfuseforthecountryofusehasbeeninstalled.
Power Line Cord - PlugonlyintoACoutlet.In U.S.A. 115VAC50-60Hz.Properoperation
willbehadfrom105-135V.Europeantunersareadjustedfor220VAC.50Hz(refertoExport
UnitsinInstallationInstructionssection).
Whentakingthetunerfromonecountrytoanother,takeitonlytoanauthorizeddealerinthe
countryofuseforproperconversion.Servicingbyuserorunauthorizedpersonnelwillvoidwar-
ranty
Output Fixed - Usethisoutputtoplugintostereopreamplifier.Delivers1 voltRMSfor
100% modulationfromaninternalimpedanceof600ohmsintoanopencircuitorhighimpedance
load. Candeliver% voltinto600ohmexternalload.CanDriveasmuchas100feetof33picofarad
cableoneachoutputlegwithoutcausinganydegenerationofsignal.
Output Level — Thisoutputconsistsofa 5,000ohmpotconnectedacrosstheoutputofthe
FixedOutput.Ithasa varyinginternalimpedancethatcannotexceed2800ohms.Itcanbeusedto
driveshortstandardcablesintohighimpedanceinputs.
External Vector Input — Inputforfour-channelsignalsourceforscopedisplaythroughthe
tuner'sfour-channelmatrixcircuit.DepresstheDisplay:ExternalVectorpushbutton.Alsomaybe
usedtomonitorexternalstereosources.UseFront,L & R inputs.
Scope - AllSequerratunersareproperlyadjustedbeforeleavingthefactory.Ifforanyreason
thescope'straceneedsadjusting,followtheproperprocedure:
1. Removeallinputs.
2. WithsmallscrewdriversettheScopeIntensityadjustmenttofullcounterclockwise
position.
3.Setscope'sFocus,Vertical,andHorizontaladjustmentstocenterposition.
4Switchpoweron.Allowa minimumof1 minutefortubetocompletelywarmup.Itis
bettertowail15minutestoallowthetunertostabilizeatfulloperatingtemperature,
thusavoidinganypossibledrifteffect.
5.DepresstheDisplay:ExternalVectorpushbutton.
5174
B

6.SlowlyturnIntensityAdjustmentClockwiseuntila verydim(barelyvisible)trace
appearsonthescope'sscreen.Itisimportanttokeepthistraceextremelydim.Auto-
maticbrighteningcircuitrywilladjusttheintensityasrequiredduringperformance.A
brightspotwillcauseburn-inandshortentheoscilloscopetube'slife.Suchusewillvoid
thewarranty.NowadjusttheFocuscontroluntilthescope'stracebecomesthesmallest
possibledot.AgainadjusttheIntensitycontrolforthedimmestpossibledot.The
VerticalandHorizontalcontrolsareusedtobringthedotintotheexactcerterofthe
scope.Toproperlycenterthedot,observethetubeexactlydead-on-centerfromthe
fronttoavoidanyparallex.Usethecenterverticallinewithitscentercrossmarkto
locatetheexactcenter.
Muting Level — Thisadjustmentisusedtotuneoutallsignalshavingnoiselevelwhichis
unacceptabletoyou.
1. DepresstheMuting:Offpushbutton.
2. Tuneina stationwhichyouconsidertobeonthethresholdofhavinganunacceptable
noiselevel.
3.DepresstheMuting:Inter-Stationpushbutton.
4. AdjusttheMutingLevelcontroltothepointwherethatstationjustmutesout.
Nowanystationwitha noiselevelequalto,ormorethanthestationjustusedwillbemuted
outasyoutunethroughtheFMband.ThismutinglevelappliestoboththeMuting:Inter-Station,
andMuting:Inter-Stereopushbuttons.ThepotentiometerusedfortheMutingLevelcontrolhasa
rangeof3 microvoltsto30microvolts.
Panoramic Sweep — Theelectronicsforthepanoramicdisplayfunctionisoptionalandisnot
includedinallsets.Again,rememberthatalltunersareadjustedbeforeleavingthefactory.But,in
theeventthepanoramictraceneedsadjustment,followtheseprocedures.Thistaskcanbemade
simplerwitha properunderstandingofwhat'sonthescreen.Theimportantthingtounderstandis:
1. Theverticallinesonthegraticulearedesignedtobe400Hzapart.
2. TheFCCfrequencyassignmentstoalternate(primary)stationsare400Hzapart.This
spacestheadjacentstationsmidway(200Hz)betweenthealternates.
Inrelativestrongsignalareas,itmaybeadvantageoustoremovetheantennaleadsandreplace
themwitha smallpieceofwire.Althoughthepipswillnotbeasstrong,theymaybemoreeasily
adjustable.
To AdjustCentering:
1. DepresstheDisplay:Panoramicpushbuttonandtunefora primarystationbycenteringa
largepip.
2. NowdepresstheDisplay:Tuningpushbuttonformoreaccuratecentertuningandchecking
thestationfrequencyonthedigitalreadout.
9
5174

3.NowdepresstheDisplay:Panoramicbuttonagain.Donottouchthetuningknob,andifthe
station'spipisoffcenter,centerthepipbyadjustingthePanoramicSweepCentercontrol.
ToAdjustWidth:
1. DepresstheDisplay:Panoramicpushbutton.
2. Selecta portionofthebroadcastbandwheretheprimaryalternatestationsarebroad-
casting.
3.Identifythepipsbyusingthedigitalreadout(switchmomentarilytoDisplay:Tuningfor
moreaccuratetuning).
4. ThenbyusingtheWidthadiustmentcontrol,alignthepipsoftheprimaryalternatestations
withtheverticallinesonthegraticule.
TheWidthadjustmentmaymovethepipsoffcenter,inwhichcasegobackandadjustthe
centering. Youmayhavetogobackandforthseveraltimesbeforeattainingoptimumalignment.
Thefinaladjustmentmaynotfallexactlyonthelines,asthescopedisplaysareapproximateand
notdesignedforhairlineperfection.A highlyusablecompromiseiseasilyachieved.
25 Microsecond Dolby - ThepresentU.S.A.Dolbystandardisfor75microsecondde-
emphasis.Europeansetsaredeliveredtooperateat50microsecondde-emphasis,whichisthe
Europeanstandard.Conversionfromonestandardtotheotherisa simplematter,butshouldbe
doneonlybya FranchisedDealer.
Presentlyinthe U.S.A. thereareconsiderationsbytheFCCofpermittingand/orstandardizing
on25microsecondoperation.Ininstancesof25microsecondbroadcastingallthatisrequiredfor
thetunertobeproperlyconvertedistoinserta shortingplugintothe25MicrosecondDolbyjack.
Detector Output — Thisoutputsuppliesa signal,beforede-emphasizing,directlyfromthe
outputoftheFMdetectorpriortomultiplexdecoding.Thisoutputhasapplicationtofour-channel
demodulation,broadcasttesting,andotherspecialpurposes.
Accessory — Whennotinuse,theshortingplugsuppliedwiththetunermustbeproperlyin
thesocket.Ifitislooseorabsent,thedigitalreadoutwillreadeither189.3MHzorbelow88.0
MHz,andturningthetuningknobwillnoteffectthesereadings.
TheAccessoryjackisusedtointerfacethetunerwithvariousaccessories,i.e.theoptional
remotepushbuttontuningassembly.
5174
10

DETAILEDDESCRIPTIONOFSCOPE
Athoroughunderstandingoftheinformationshownbytheoscilloscope'stracewillgivean
appreciationofwhalisbeingbroadcastplusthequalityofthebroadcast.Thispresentsanoppor-
tunitytomakeallowableadjustments,withthetunerandantenna,toachievethebestpossible
receptionofreceivableprograms.Allscopemeasurementsandtraceinformationareapproximate.
Theyareusedtoestablishreferencesandarenotdesignedforhairlineaccuracy.
Thecathoderaydisplaytuberequiresgreaterwarm-uptime(about30seconds)thanthedis-
playsbeforethetracebecomesvisible.
Theoscilloscopedisplaydimsautomaticallywheneverthetracereducestoa "dot"(atlowor
noaudiosignallevels).Thisautomaticdimmingactionextendsthelifeofthecathoderaytubeand
reducesthepossibilityofaccidentlyburningthescreenphosphors.
Panoramic — Inthismodethescdpedisplaysallstationsbroadcastingwithina 2 MHzspec-
trum. (1MHzeachsideofthetunedfrequency).Theheightofthepipsindicatetherelativesignal
strengthofthestations.Thenoticeablemotionofthepipsistheresultofthematerialbeingbroad-
castedplusmultipath.Thepanresponseisflatatthecenteralthoughnotacrosstheentire2 MHz.
Thiswillcausesomeslightdiminishingoftheheightofthepipsastheyaretunedacrosstheband
awayfromcenterfrequency.Theheightofthepipsindicatetherelativesignalstrengthofthe
stationsandcorrespondstotheapproximateheightofthetraceofthetuningdisplay(secondpush-
button). Thisisjustanapproximateheightmatchasthecenterverticallineonthepandisplayhasa
dynamicrangeofapproximately100dB.Thisistheresultofsomeslightcompressionatthetopand
displacementatthebottom.Theverticalcenterlineonthegraticuledelineatesthecenterfre-
quency.Thetwoverticallinesoneithersideofthecenterlinearespacedatintervalsof400kHz.
ThisspacingcorrespondstotheFCCspacingofalternatestationsonthebandwidth.Adjacent
stationsfallmidwaybetweenthealternatesat200kHzspacings,andwhenthesetistunedwitha
primarystationonthecenterline,thealternatestationswillbeontheverticallines,whilethead-
jacentstationswillfallbetweenthelines.
Athree-pointedtracerepresentsa stationwithanSCAsubcarrier.SomeFMstationssimul-
taneouslybroadcasta SubsidiaryCommunicationsAuthority(SCA)signalonthesamecarrierfre-
quencyastheirregularbroadcast.SCAbroadcastsareprivatelysoldtocommercialuserssuchas
restaurants,offices,stores,etc.,andcontainnocommercialadvertising.
NOTE: Allspectrumanalyzersproducea varyingnumberofambiguousanderroneousdisplays.
ThePanoramicDisplayintheModel1 Tunerisnoexception.Thetypesoferroneousdisplaysthat
youmayexpectarelistedasfollows:
1. Image Responses: Allstationshavinga signalstrengthofgreaterthan5000microvoltswill
produceanimageresponseinthedisplayprecisely4.8MHzabovethestation.
2. Spurious Responses: Theseresponses,inthistuner,areattributedmainlytothedynamicrange
limitationsofthesystem.Thedynamicrangeupperthresholdis100,000microvolts.Signal
inputgreaterthanthatproducessignificantdisplacementofthebaselineaswellasa seriesof
sidebandmodulationproducts.
11
5174

3. Crossmodulalionproductsduetotheoutofbandsignalsi.e..excessivelystrongtelevision
signalsbelowtheFMbandandexcessivelystrongaircraftsignalsabovetheFMbandmay
producespuriousresponses.
4. ClandestineFMtransmittersi.e.,buggingdevices,radiationfromotherFMtuners,andother
sourcesofelectromagneticradiationwithinthebandwillbereadasresponsesinthePanoramic
Display.
Tuning — Theoscilloscopetracefollowsanapproximatetrapezoid.Spinningthetuningknob
fastwillgiveanideaofthebandpasspattern.Signalstrengthisindicatedbytherelativeheightof
thetraceabovetheinter-stationnoiselevel(thelowerandheavierhorizontalpathofthetrace).The
centergraticulelinedisplaysa dynamicrangeofapproximately110dB.Itisdividedintodecades.
Thesecalloutsarenotmeanttobeexactbutareonlyapproximate.They'regivenforrelativedis-
cernmentofsignalstrength.
Modulation(orcarrierdeviation)isdisplayedbytheinstantaneoushorizontalexpansionand
contractionofthetracewhentunedattheuppercenter.Loudpassagesareindicatedbywide
traces,whilesofterpassagesareseenasproportionallyshortertraces.Over-modulationbythetrans-
mitterisdisplayedasanexcessivelywidetraceextendingbeyondthetwoverticallinesoneither
sideofthecenterline.Theseverticallinesrepresenttheinstantaneouspeakdeviationof75kHz
eithersideofthecenterline.
Weakdistantstationscanbeseenonthescopealthoughtheymaybebelowthetuner'sset
mutingthreshold.Adjustingantennadirectionwillfrequentlyincreasesignalstrengthsufficientlyto
pullthesignaloutoftheinter-stationnoiselevelandgivegoodreception.Inextremecases,a very
weaksignalcanbemadeaudiblebysettingMutingtoOff.
AstationbroadcastinganSCAsidebandcanalsobeseenwiththeTuningDisplay.Itis
detectedbyaninwardreachofthetracewhenthetraceisattheupperportionofeithersideofthe
tracepattern.
Adjusting Antenna Direction For Minimum Multipath — Thetuningdisplayservestheim-
portantfunctionbyshowingwhentheantennaispointedtobestpossibledirectiontominimize
multipath.Multipathinterference,similartoa "ghost"inTVpictures,producesdistortioninthe
FMsignalsatthereceivingantenna.Thisresultsina distortedsound.Tominimizemultipathinter-
ference,andobtainthebestreceptionfromeachstation,adjusttheantennatothedirectionwhich
resultsinthesmoothestandmosthorizontaltrace.Thisdirectionfrequentlymaynotbethesame
asthedirectionforthestrongestsignal(maximumverticaldeflection).
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PANORAMIC
GRATICULEDESCIRPTIONS
'400kHzSpacings
2MHz
FrequencySpectrum
IdealDynamicRange
-120dB,lV
T00dB,100,000uV
•80dB,10,000uV
60dB1,000uV
40dB,100uV
20dB,10uV
100dB
ActualDynamicRangedueto
compressionattopanddis-
placementatbottom
517
00
13

PANORAMIC
DESCRIPTION OFPIPS
A. Tuned instationon
centerfrequency.
B. Alternatestation400
kHz offcenterfrequency
C. Alternatestation800
kHz offcenterfrequency.
Note:3-pointedpipindicates
stationsimultaneously broad-
casting SCA.
D. Adjacentstation200kHz
off centerfrequency.
Samebroadcastreceivedby2 differentantenna
systems.
A. Rabbit ear FM antenna
B. Outdoorroofantenna (note overload). This was
close line-of-sightdeveloping0.3Vinputto tuner.
2" Stationswithsamesignal
strength
A. Monaural
B. Stereophonic
C. Bendattopofpip
Indicates stereo pilot.
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14

TUNING
5174
75kHzSpacings
Typical
(complete cycle)
Trace Pattern
Amplitute(SignalStrength)
Noise Level
Noise Density
Graticule Description
Trace DescrlDtlon
For DynamicRangeseePanoramicGraticuleDescription
15

TUNING
TRACE DESCRIPTIONS
Soft Passages
Loud Passages
(Full Modulation)
Over/modulation by
broadcaster
(causes distortion)
Station not properlytuned
Off-Tuned trace
(ShowingSCA sub-
carrier)
Weak Station
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StationwithLowAmplitude Stationwith
High Amplitude
16

TUNING
MULTIPATH
Ideal Trace
(NoMultipath)
Multipath progressivelyworse(AtrhoughE).Thelong
gentle curveofA ispreferableto B,etc.Intuningto
eliminateorminimizemultipath,rotateyourantenna
togetthe smoothest trace. This willbeyour best
listeningposition,evenIfithas less amplitudethan
in otherpositions.
Very severe multipath
(partial cancelationofsignal)
5174
17