DRAKE FS-4 User manual

€m MODEL
FS-4
v FRRE@,uEIvc.Y
SYA'THEg'IZEtrI

t-
LIMITEDWARRANTY
R. L. DRAKE COMPANY warmnts to the orígínal purchaser that thís product
shall befree from defects ín materíal (except tubes and RF output transistors)
or workmanshipfor ninety (90) daysfrom the date of original purchase.
During the wanonty period the R-L. DRAKE COMPANY or an authorized
Drake servicefacility will provide ftee of choge both ports (except tubes and
RF output fiansistors) and l¿bor neces$lry to correct defects in material or
workmanship.
To obtain suchwananty semíce,the original purchasermust:
(
I) Completeand sendin the tilananty Registration Card.
(2) Notify R. L. DRAKE COMPANY or its nearestauthorized service
facility,
assoonas
possibleafter discovery of apossibledefect, of:
(a) Themodel numberand serialnumber, if any;
(b) The identity of the seller and the approxinute date of purchase;
(c) A detail¿d description of theproblem, including details on the elecffí'
calconnection
to associated
equipmentandthelist of such equipment.
(3) Deliver the product to theR.L. DRAKE COMPANY
or thenearest
author-
ized service
facility, or ship the samein its original container or equívalent,
fully ínsureda¡tdshipping chmges
prepatd.
Conect maintenance,"repair
ond useare important to obtain proper perform'
ance from this product. Thoefore, carefully read the Instruction Manual. This
warranty does not apply to any defect that R. L. DRAKE COMPANY deter-
minesisdueto:
(1) Improper maintenance or repair, includíng the installation of parts or
accessories
that do not conform to the quality and speciftcations of the
original parts.
(2) Misuse,
abuse,neglector improper installation.
(3) Accidental or íntentional damage.
All ímplied warranties,
if any, terminateninety (90) days
fiom the dateof the
originalpurchase.
The foregoing constítutesR. L, DRAKE COMPANY'S entire obligation with
respect to this product, and the oríginal purchaserand any user or owner shall
haveno other remedy and no claím for incidental or consequentialdamages'
Some statesdo not allow limitations on how long an implied warranty lastsor
do not allow theexclusion
or limitation of íncidental
or consequential
damages,
sotheabove
limitatíon andexclusionm0ynot apply to you.
This wananty gives specific legal rights and you may also haveother rights
which varyfrom state to state.
R. L. DRAKE COMPAI{Y
540 Rich¡rd Street o Miamisburg,Ohio45342
PRINTED IN U.S.A.

YCHAPTERI
INTRODUCTION
1.1.GENERALDESCRIPTION,
The FS4 is a frequency synthesizerdevelopedfor usewith the Drake
Company "4" line equipment. (R4 series,T-4X seriesand SPR4.) The
FS-4 plugs into an unused auxiliary crystal socket in the rear of the
receiver
or transmitter, and will supply the variousinjection signalsto the
eguipment and allowscontinuous coverage
without utilizing the accessory
crystals.
The frequency readout on the FS4 displaysthe receivedfrequencyband,
andto thisis addedthe frequencyreadoutofthe receiver
"PTO" to obtain
the correctreceived
frequency.
The FS4 suppliesall the crystal oscillator injection signalsfor the R4
series
and T4X seriesin 0.5MHz stepsfrom 11.1
through40.6MHz,and
the readout is ürect. An accessorykit is availableto provide proper
injection signalsfor the SPR4 receiver.
The FS4 canbe usedwith the 21 type receiver
overthe frequencyrange
of 7 to 30 MHz. Whenusedwith the 24, receiver,
the FS-4frequencyread-
out isnot direct,andacorrection factor of "7 MHz" must beaddedto the
FS-4 readout to obtain the correct operatingfrequency.A special
acces-
sorykit isnecessaryto modify the FS4 for usewith the 2-Creceiver.
1.2.MANUAL
COVERAGE.
This manual is presented
in 5 chaptersandisarrangedfor the convenience
ofthe operatorandservicetechnicianasfollows:
CHAPTERI Introduction.
(Self
explanatory.)
CHAPTERII Installation. Describesthe procedures
to befollowed prior
to operation.
a
JANUARY
1977

CHAPTER
III
CHAPTER
IV
CHAPTER
V
Operaüon.
Illustrates
anddescribes
front panel
controls,
and describes
operation
with Drakereceiver/transmitter
equipment.
Theory
of Operation.
Describes
all circuitsand
networks.
Maintenance.Provides niaintenanceand alignment
instructions.
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Y
CHAPTER
II
INSTALLATION
2.1.UNPACK¡NG.
Carefully
removethe FS4 from the shippingcartonandexamine
it for
evidence
of damage.
If anydamageisdiscovered,
immediatelynotify the
transportationcompany
thatdelivered
theunit.
NOTE
Fill out the enclosed
registrationcard and return it to
the factory immediately to insure registration and
validation of the warranty.
2-2. LOCATION.
The FS4 issupplied
with a cable
approximately
20incheslong
that plugs
into the accessory
crystalsocketof the receiver/transmitter.
Thislength
allowsthe user
to place theFS-4on either
sideof thereceiver/transmitter.
Placingthe FS4 on top of the transmitteris not recommended,dueto
heatgenerated
within thetransmitter,
andtheFS4 will blocktheairflow.
2.3. POWER
REOUIREMENTS.
The FS4 is shippedfrom the factory wired for 120 VAC, 50160
Hz,
operationunless
otherwise
specified.
To operateon 240VAC makethe
properconnections at thetransfornerontheparent
board
asillustrated
in
figure
2-1.
24. FUSE.
Thepowerlineisfused
for 120
VAC operation
with a 3AG Typel/84,
Slo-Blo.
For 24OVAC operationuse
a3AGType1l16A, orequivalent.

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CHAPTERIII
OPERATION
3.1.CONTROLSANDDISPLAYS.
All controlsand displaysnecessaryfor the operationof the FS4 are
locatedon thefront panel. The
th¡eeknobsswitch
thefrequencyrangein
.5MHzstepsand
provide
direct
frequency
displayin MHzatthereadout
directlyabove eachknob.These
knobs
switchthefrequencyin steps
of
l0 MHz,I MHz,
and
0.5MHz
fromleft to right.The0.5 MHzknob
also
turnstheFS-4 onandoff. Referto figure3-1.
3.2.INJECTION
CABLE.
The injectioncable supplied
is usedto connect the FS4 to anunused
accessorycrystalsocket
of thereceiveror transmitter.Attachthe
ground
lugto thechassis
at theaccessorycrystal
socket
and
insert
thecenter
pin
into theselectedaccessory
crystal
socket.
Thereceiver ortransmitterwlll
operatebestwhen
the
center
conductorisconnectedtothe emitter
ofthe
crystaloscillator.
Thiscanbedetermined
bynotingtheS
meter
reading
or
power
outputreadoutwhen
theinjectioncable
isplugged intoeach socket
oftheaccessorycrystal
socket.
3.3.BANDSELECT.
Whenusingthe FS-4to controla receiveror transmitter,
the receiver/
transmittermustbe
placed
inthe
proper
bandas
youwould
innormal use,
andthecrystal
switchmust
beplaced in theposition corresponding
with
theposition selected
to plug intheFS-4.TheRFtune
(preselector)
ofthe
receiver/transmittermust
betuned
thesameas
innormal
use.
34. PRESELECTOR
SETTING.
A stick-on-decal has been supplied for convenience in loca*ing
positioning of the RF tune (preselector).
This may be applied to
receiver/transmitter front panel by removing the knob and aligning
decalon the front panel
andfirmly rubbingit on.
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cautionmustbe used
on proper
use
of theFS4 when
used
with trans-
mitters.
consult RF Tunecalibration
chartsin the manual
of theT-4x
series.
3.5.
TUNING
A RECEIVER
AND
THE
FS4.
a. Switch
theFS-4
to thedesired
operating
frequency,
asan
example:
7.0
for40meter
amateur
band.
b. Place
theR-4Receiver
"Xtals" switch
in position
l0 (assuming
the
FS-4
isplugged
intoaccessory
crystal
socket
+10).
c. Setthe
R4 "Band"
switch
to 2.0.
d. Set
"PRESELECTOR"
control
between
5and
6.
The
FS-4
and
receiver
are
now
correctly
set
forproper
operation.
The
rest
of theoperatingprocedure
is
called
out
inthereceiver/transmitter
instruc-
tion
manual.
3-6. MODIFICATION
OFTHE
FS-4
FOR
USE
W|TH
THE
SpR-4
or 2-C.
The FS4 canbemodified
fromthestandard
version
to operateproperly
with the SPR-4
or 21 by simplyremoving
the caseof the FS4 and
exchanging
thereference
crystalasshown
in figure
5-1,
and
substituting
the interconnecting
cablewith onethat has
aplugwhich
fits theSpR-4
accessory
socket.
Drill a ll4" üa.holein therearpanel
of theSpR-4
or
21, and
insert
grommet.
Feed
theFS4 injection
cable
through
thishole
toan
unused
crystal
socket.
Thecorrect
reference
frequency
crystal
for theequipment
isshown
in the
chart
below:
Controlled
Equipment FS-4
Reference
Crystal
R4 and
T4X
SPR4
24,
*7 MHz must be added to
frequency.
9.6MHz
9.59-
9.5*
the FS-4 readout for proper operating
7

The FS4 should be unplugged
from the receiver
or transmitter if opera-
tion is desiredfrom internal crystal control and not by useof the FS4.
The cable capacity of the FS4 can causeoscillation of the receiveror
transmitter that isnot controlled by the selected
crystal.
NOTE
No tuning of L406 is required when exchangingthe
referencecrystal for "qse
with the SPR4. Someadjust-
ment may be requiredwhen exchanging
the crystal for
use with the 21. See paragraph 5-3, for the proper
tuning procedure.
when using the FS4 to control the frequency of the 21 the vFo dial
alwaysreads
on the black scale.
The red scale
doesnot apply whenusing
the
FS4.
3.7. FREOUENCY
ACCURACY.
All injection frequencies
in the Fs4 arederived
from the 5MHz clock and
the réference oscillator. Any frequency error in the injection signalis
essentiallythe sameat any frequency band.when derivingthe injection
frequency by useof crystalsin the crystal oscillator in the receiver,
asis
normally done, the frequency error will vary from bandto bandasdiffer-
ent crystalsare switchedin. This error is compensated
for when thePTO
iscalibrated.
A differencein frequencymay benoted when switchingbetween
standard
operate
andFS-4operate.
This error isdueto crystalerrorsasstated
above
and in generalthe use
of the FS4 results
in the better frequencyaccuracy.
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I

CHAPTERIV
THEORY
OFOPERATION
4.1.GENERAL.
Referto theblockdiagramin figure4-1for circuitoperation.
4.2. VOLTAGECONTROLLED
OSCILLATOR
(VCO}.
The VCO is a voltagecontrolledoscillator
capableof operation
overthe
frequencyrangeof 10.5 to 4l MHz, and is usedto providethe crystal
oscillatorsignalrequiredin the receiver/transmitter
for properoperation.
4.3. D.BALANCEMIXER.
A signalfrom the VCO is appliedto the D-BalanceMixer, whereit is
mixed with the signalfrom the lockedoscillatorto produce
an output in
thefrequencyrangeof approximately1I to l6 MHz.
4-4, LOCKEDOSCILLATOR.
Thelockedoscillator
developssignalsof 5, 10,l5,2O,and 25MHzwhich
aresynchronizedto a 5MHz reference
signal.The actualoutput of the
lockedoscillatoris determinedby the settingsof thefront panel
switches.
The output is zerofor settingsof 0 to 4.5MHz,5 MHz for settingsof 5 to
9.5MHz, etc.This output ismixedwith theVCOto produce
signalsof 11
to 16
MHzwhicharefedto thebandpassfilter.
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4.5. BANDPASS
FILTER.
The bandpass
filter following the
order products from the mixer
harmonics.
D-BalanceMixer suppressesany higher
as well as the two inputs and their
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tr 4.6. REFERENCEOSCILLATOR.
The output of the bandpass
filter is then mixed in the second
mixer with
the reference
oscillator. The referenceoscillatorfrequencydetermines
the
bandedgesof the injectionoutput, that is, 16.l asrequired
in an
R4, vs.
16.09
for the SPR4, vs.16.0asrequired
by the 2{ (seeparagraph3-6).
The resultant output from the secondmixer is in the rangeof 1.5 to
6 MHz and is applied to the low pass filter to suppressany higher
frequencyoutputs.
4.7. PHASE/FREOUENCY
DETECTOR.
The output of the low pass
filter is applied to a programmablecounter,
which is programmedfrom the 1MHz and 0.5 MHz controls, and divides
the input by an appropriate
numberbetween
3 andl2 to produce
an
out-
put near
0.5MHz. The output is applied
to thephase/frequency
detector,
where it is comparedin phaseand frequencywith the resultant 0.5 MHz
signal obtained by dividing the 5 MHz clock by 10. An error signalis
developed
in the phaseifrequencydetector which is appliedto a voltage
variablecapacitor
in the VCO, andforcesthe frequency
to be such
that
the resultant input to the phase/frequency
detectoristhe samefrequency
asthat derived
from the clock (500 kHz).
J
\ 4-8.PROGRAMMABLE
COUNTER.
I fhe programmable
counter
is controlled
by the I MHz and0.5MHzcon-
t trols,andcovers
arangecountof 10,starting
at3,at dialsetting00.0,and
,f progressing
one count for an increasein the 0.5 positionof a two count
for each
increase
in the 1MHz control.
Thecounter
increases
to 12atthe
settingof 4.5 and then startsoveragainat ,5.0andrepeatsevery
5 MHz
rangeof theFS4.
11

4-9.
SIGNALS
PRESENT
AT DIALSETTING.
The following is an exampleof actual signals
presentfor the FS-4setat a
dialsetting
of l2.5MHz:
Dialsetting
= 12.5MHz
VCOFrequency
=23.6
LockedOscillator
= l0 MHz
D-Bal.
MixerOutput
=23.6
-lO= 13.6
Second
MixerOutput
= I3.6
-9
.6
=4
+N
output
=4i8=0.5
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12

¿
CHAPTERV
MAINTENANCE
5-1.ALIGNMENT.
The FS4 hasbeencarefullyalignedandtestedat the factory for proper
operation
andshouldnot berealignedunless
required
andthenoniy by a
knowledgeable
and
competent
technician.
5-2.5 MHzCLOCKALIGNMENT.
Tune in andzeto beat a signalfrom WWVusing
the internal crystalof the
receiver.Without movingthe frequency dial of the receiver, couplethe
receiverantenna
to theFS-4
case
or ground. TunecapacitorC303for zero
beaton thereceiver.Referto fieures
5-l and 5-2.
NOTE
A higher frequency of WWV signal provides greater
accuracy,as the above
processprovides
tuning of the
5MHz clockby tuning
in aharmonic.
5-3.REFERENCE OSCILLATOR
ALIGNMENT.
For a high degree
of accuracy
the referenceoscillatorshouldbe tuned
usinga frequency counterconnected
to the injectionoutput ofthe FS4.
SettheFS4 dialto 00.0andtuneL406 for 11.1MHz.
NOTE
If using a referenceother than 9.6 MHz, tune the
injectionoutput frequency1.5MHz above
thereference
crystal
frequencyasspecifiedin paragraph
3-6.
This oscillator
may be tuned
for operationwith verylittle frequencyerror
merely by tuning for maximumRF voltagemeasuredat testpoint A on
bottomof parent board.
NOTE
It is not necessary
to realignthe oscillatorwhen
changingthecrystal
asspecifiedinparagraph
3-6.
J
13

*
PARENT
BOARD
(A400)
DIGITAL
BOARD
(A300)
c303
v
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L203
t204
LOCKED
OSCI
LLATOR
BOARD REFERENCE
CRYSTAL
L202
L201
L205
L101
L102
1103
1104 Ll05 L107
Figure5-1. Top View with Case
Removed
L106
14

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54. LOCKED
OSCILLATORALIGNMENT.
Tune the indicated coilsfor maximum RF output voltagemeasured
at test
point B (on bottom of parent board) when the FS4 is tuned to the
indicated
dialsetting:
DIALSETTING MHz TTINECOIL
05.0
10.0
15.0
20.0
25.0
L205
L202
L204
L20l
L203
5.5.VOLTAGE
CONTROLLED
OSCILLATORALIGNMENT.
The VCO may be tuned usingafrequency
counterconnectedto theinjec-
tion output of the FS4. If thesystemisoperational
onmostdialsettings,
the oscillator
may be alignedby monitoringthecontrollinevoltage
under
locked
conditions.
FREQUENCY COT.JNTERMETHOD.
Disconnect the control line cable at the VCO board and apply a well
filtered DC voltage of 1.5V to the control line input of the VCO. (This
may be obtained by using a potentiometer of at least 5 kl) connected
acrossthe 12volt supplyto ground.)
Tunetheoscillator
for theindicated
frequencywhentuned to the specified
setting:
DIAL SETTING TI.JNECOIL FREQUENCY
J00.0
01.0
03.0
0s.0
07.0
10.0
20.0
L105
L10ó
Lt07
L103
Ll04
Ll0l
Lr02
15
10.6MHz
11.6MHz
13.6
MHz
15.6MHz
r7.6MHz
2O.6MHz
30.6MHz

LOCKEDIOOPMETHOD.
If theFS4 isoperational
onmostfrequencies,theVCOmaybetunedby
monitoringthevoltageatthecontrollineunderlockedconditions.
Donot
disconnectthe controlline as
in the method above.
Connect
aDCvolt
meterto thecontrollineattheVCOboardandtunetheindicatedcoilfor
thespecifiedcontrol
line
voltage:
DIAL SETTING CONTROL
LINE
TI'NE COIL VOLTAGE
-
00.0
01.0
03.0
0s.0
07.0
10.0
20.0
Ll05
Ll06
LloT
Lr03
Lt04
Ll0l
Lt02
2.9VDC
2.7VDC
2.4VDC
2.3VDC
2.3VDC
3.0
vDc
2.6VDC
v
16

DRAKE AMATEUR PRODUCTS
R-4C Receiver,
covers
the 160 meter through l0 meteramateurbands
and
up to ftfteen additional 500 kHz rqnges.It has 8-polecryls.tll^fíltel
sétectiiiiy wíth passbandtuning and transceives
with the T-4XCwith
exc
ellentsensitívítY.
T-4XC Transmitter, covew the 160 through 10 meter amateurbands
and
most otherfrequencies
between
1.5and30MHz. It has8-polecrystal
filters for sideband
selectíon.
It may beusedto transceive
with the
R-4C.
TR-4C Transceiver,
300 l4tatt
highfrequency single-sideband
unit covers
the
80 meter through 10 meter ámateur bands.
IncludesAM and CW
modes,a linear-,
permeability'tuned VFO and two 8-pole crystal
lattice
ftlters.
L-48 Linear Amplifter, built for contínuousduty qt full-capacity. 200^0
Watts
PEP-oi SSB.
1000
Wattson
AM, CI| and
RTTY. Covers
the80
meter
throughI0 meterbands.
SPR-4 An all solid-state
communicattons
receíver
whichcanbe
programmed
with accessory
crystalsto cover 150 kHz to 30 MHz. The SPR-4
receives
AM, CW,'SSB,
(upperand lower) and may be
powered
ftom
120 VAC,240 VAC,
and
12 VDC.
FS-4 Frequency Synthesizer,built for use with R-4 seríes,
SPR-4' 2'C
receivers,
and T-4Xseries
transmitters.
MN-4 Antenna MatchíngNetwork, matches50 Ohm tansmitter output to
coax antenna
feedlínewith VSWRup to 5:1. An integral W-a-ttmeter
reads forwarri power in Watts ond VSl4tR directly. 200 lüatts
continuous
duty output.
MN-2000 AntennaMatching
Network. Same
asMN-4 except: 1000 lilatts con'
tinuous duty output (2000 WattsPEP) and 3 antennaconnectors
switch
-s
elec
tablefrom front panel.
W-4 Wattmeter, readsforward and retlected power directly ín Wa¡ty
(VSIIR from nomógraph).
Range:200 and 2000 Watts
full scale,
1.8
to 54MHz.
WV-4 Wattmeter, readsforward and reflected power directly ín Watls
(VShtRfrom nomograph).
Range:100 and 1000 Watts
full scale,20
to 200MHz.
TR-33C Tiansceiver, 2 meter VHF-FM, portable. Twelve channels, self
contaíned
batteries
andattached
microphone.
RCS-4 Remote CoaxSwitch, providesremoteselectíon
of up to five anten'
nas, using only one main feedlíne. Allows grounding of unused
antennas.Moior driven switches controlled from stat¡on located
console.
SSR-1 General
Coverage
Receiver,0.5'30 MHz continuous.All solid state.
For ínformation on any of our products. please
feel free to write our Sales
Deparíment. 540 Richard-Streei, Miamisburg, Ohio 45342 or call direct,
513-866-2421.

9
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