DRAKE T-4B User manual

INSTRUCTION
MANUAL
Z
ddd.
LL
ldams
:
RICE OF INSTRUCTION MANUAL $2.00
AL. DFA
KE COMPANY - MIAMISBURG, OHIO

STANDARD WARRANTY
R, Le DRAKE COMPANY warrants each new radio product manufactured by
it to be free from defective material and workmanship and agrees to
remedy any such defect or to furnish a new part in exchange for any
part of any unit of its manufacture which under normal installation,
use, and service discloses such defect, provided the unit is de-
livered by the owner to us or to our authorized radio dealer or
wholesaler from whom purchased, intact, for our examination, with all
transportation charges prepaid to our factory, within ninety days
from the date of sale to original purchaser and provided that such
examination discloses in our judgement that it is thus defective.
Should a malfunction be suspected, write in detail to our Service
Department for suggestions concerning the operation, repair or return
of your unit if it should prove necessary.
This warranty does not extend to any of our radio products which have
been subjected to misuse, neglect, accident, incorrect wiring not our
own, improper installation, or to use in violation of instructions
furnished by us, nor extend to units which have been repaired or
altered outside our factory, nor in cases where the serial number
thereof has been removed, defaced or changed, nor to units used with
accessories not manufactured or recommended by us.
Any part of a unit approved for remedy or exchange hereunder will be
remedied or exchanged by the authorized radio dealer or wholesaler
without charge to the owner.
This warranty is in lieu of all other warranties expressed or implied
and no representative or person is authorized to assume for us any
other liability in connection with the sale of our radio products.
The R. L. DRAKE COMPANY reserves the right to make any improvements
to its products which it may deem desirable without obligating itself
to install such improvements in its previously manufactured products.
Ro Le DRAKE COMPANY MIAMISBURG, OHIO 45342

TABLE
GENERAL
SPECIFICATIONS---------------
MODES
OF
OPERATION-------------------
CONTROLS
&
JACKS---------------------
POWER
REQUIREMENTS-~-----------------
POWER
SUPPLY
SPECIFICATIONS----------
TUBES
&
SEMICONDUCTOR
COMPLEMENT----~-
Il.
IIt.
IV.
DESCRIPTION---------------------
INSTALLATION
INSTRUCTIONS
-------
A.
Unpacking
B. Location
C.
Power
Requirements
D.
Antenna
Requirements
E. Receiver Muting
F.
Receiver
Antenna
Switching
G.
Anti-Vox
&
Sidetone
H. R-4 Injection
I.
Microphone
Requirements
J. Speaker
K. Ground Requirements
L.
Linear
Amplifier
Connection
CONTROL
FUNCTIONS---------------
A.
Front
Controls
B.
Side
Controls
&
Jacks
C.
Rear
Connections
&
Controls
D.
Inside
Controls
TUNING
PROCEDURE------------7777
A.
Bias
Adjustment
B.
Tune
Up
on
Desired
Band
C.
Carrier
Balance
Adjustment
D.
Transceive
Alignment
OPERATION---------erre-
rrr
rrr
A. Voice Controlled & PIT
Operation on SSB
B. CW Operation
Cc. AM Operation
D. Spotting
E. Transceiving
F.
Operation
on
Accessory
Tuneable
Ranges
G.
Crystal
Controlled
Operation
H.
Operation
with
a
Linear
Amplifier
I.
RTTY
Operation
with
an
R-4/R-4A/R-4B
and
T-4B
DADUNUNMUNUNPR HLH
OF
CONTENTS
PAGE
VI.
THEORY
OF
OPERATION------------~-
27
VII.
SERVICE
DATA---------<c-r-er-
A>
29
A. Removing Top Cover 29
B.
Removing
Bottom
Cover
29
C.
Tube
Replacement
29
D.
Trouble-Shooting
29
VIII.ALIGNMENT
INSTRUCTIONS
---------
34
A.
Adjustment
of
RF
&
34
Mixer Stages
B.
Carrier
Osc.,
Filter
Match
35
&
Balanced
Modulator
C.
Neutralizing
Final
Amp.
35
IX.
AC-4
POWER
SUPPLY--------<-c---"
37
X.
DC-4
POWER
SUPPLY------------77
38
CHARTS & ILLUSTRATIONS
MILA
SS
OS
Ee
eee
PAGE
Microphone
Wiring
Dwg.----
6
Connecting
T-4B
to
R-4B---
7
Connecting
T-4B
to
a
LA---
7
Connecting
T-4B
to
a------
8
Receiver.
-----------r
one
8
Viewing
Angle
Options-----
8
Side
View
T-4B------------
12
Rear
View
T-4B------------
12
TR-448
Illustration-------
23
RF
Tune
Curves------------
24
FSK
Circuits--------------
25
Block
Diagram
T-4B--------
26
Resistance
Chart----------
30
Voltage
Chart-------------
30
Top
View
T-4B-------------
31
Bottom
View
T-4B----------
32
8
Pole
Crystal
Atten.-----
20
C
t
ey
Chart
HCO
Sematic----
oe
en
es
37
DC-4
Schematic------------
39
T-4B
Schematic--(fold
out
page)

GENERAL
SPECIFICATIONS
Frequency
Coverage:
3.0
to
30
MHz
except
5.0
to
6.0
MHz.
11.0
to
11.5
MHz
used
crystal
control
only.
In
addition
either
1.8
to
2.3
or
2.0
to
3.0
MHz
will
be
included.
Frequency
Control:
By
tuneable
oscillator
and
range
crystals
in
R-4,
R-4A
or
R-4B
Receiver
or
by
one
of
the
ten
crystals
available
by
front
panel
switch.
Crystals
must
be
ordered
separately
specifying
transmitting
frequency
desired.
A
frequency
control
switch
is
provided
on
front
panel
to
select
tuneable
tran-
sceive,
crystal
control
transceive,
or
tuneable
receive
with
crystal
control
transmit.
Stability:
Less
than
100
cycles
after
warm
up.
Less
than
100
cycles
with
10%
change
in
line
voltage.
MODES OF OPERATION
SSB:
Upper
or
lower
sideband
on
all
bands.
Vox
or
Push-to-Talk.
CW:
Grid-block
keying.
Vox
circuit
is
keyed
for
automatic
transmit
receive
switching.
Sidetone
oscillator
is
keyed
for
monitoring.
Shifted
carrier
system
has
no
spurious
output.
AM:
Controlled
carrier
AM
modulation
is
built
in.
This
system
is
compatible
with
SSB
linear
amplifiers.
Vox or Push-to-Talk.
RITY:
Adaptable
to
RTTY
operation.
SIDEBAND
SUPPRESSION:
60
dB
or
bettero
CARRIER
SUPPRESSION:
60
dB
or
better.
AVERAGE
DISTORTION
PRODUCTS:
In
excess
of
30
dB
down.
FREQUENCY
RESPONSE:
Through
the
filter,
350
to
2750
cycles
at
6
dB
down.
INPUT
POWER:
SSB
and
AM
-
200
watts
PEP.
CW
=
200
watts.
OUTPUT
POWER:
SSB
and
AM
-
120
watts
PEP
or
more.
CW
-
120
watts
or
more.
OUTPUT
IMPEDANCE?
Nominal
52
ohms
adjustable
with
pi-network.
(SWR
should
be
2:1
or
less).
MICROPHONE
INPUT:
High
impedance.
AGC:
Operates
on
SSB
to
prevent
flat
topping
due to overdrive.
1.

CONTROLS AND JACKS
FRONT: Crystal Switch, Function Switch, Sideband Selector, Band
Switch, RF Tune, Gain, Plate Tuning, Plate Loading, Fre-
quency Control Switch, Plate Current/Relative Output Meter
Switch and Crystal Control Indicator Light.
SIDE: Anti-Vox/Sidetone Gain, Vox Gain, Microphone Jack, Xtal
Access Door with Frequency Chart.
REAR: Power Connector, Mute Jack, Receiver Antenna Jack, Anti-Vox/
Sidetone Jack, Key Jack, Antenna Connector, Ground Post, Speaker,
R-4/R-4A/R-4B Injection Jack, and Vox Delay Potentiometer.
INSIDE: Carrier Balance Control.
DIMENSIONS: 54" high, 10-3/4" wide, cabinet depth 11-5/8", overall
length 12-1/4",
WEIGHT: 12 pounds, 7 ounces.
POWER REQUIREMENTS :
Model AC-4 Power Supply - operates on 120 or 240 V. 50/60 Hz. or
Model DC-4 Power Supply - operates on 12 V. DC negative ground and has 120 V.
300 - 400 Hz output to operate R-4/R-4A/R-4B Receivers.
POWER SUPPLY SPECIFICATIONS:
1. 650 volts at 200 ma average and 330 ma maximum with 10% regulation from
66 ma to 330 ma and maximum ripple of less than 1%.
2. 250 volts at 120 ma with 10% regulation from 82 ma to 120 ma.
This includes the effect of the 650 volt supply change if both voltages
are obtained from the same transformer. .
Maximum ripple must be less than 1/4%.
3. -45 to -65 V DC adjustable filtered bias into 33 K ohm load.
4. 12.6 volts AC or DC at 3 amps.
TUBES AND SEMICONDUCTOR COMPLEMENT
NUMBER FUNCTION
12BA6 IF Amplifier
12BY7 Driver
2 - 6JB6 Power Amplifier
12AX7 Mic. Amp/Sidetone Osc.
6EV7 VOX Amp.
6HS6 Buffer
6AU6 AM Modulator
12AX7 AGC Amp. Carrier Osc.
OA2 Voltage Regulator
3 - 1N483A VOX & Anti-Vox Rectifiers
4 - 1N541 Balanced Modulator
1N483A Trigger
1N270 Output Meter Detector
6AU6 Mixer
1N483A Sidetone Keyer
MPF - 102 Xtal Oscillator

I. DESCRIPTION
The
R L
DRAKE
Model
T-4B
Transmitter
offers
selectable
single
sideband,
semi
break-in
CW,
and
controlled
carrier
AM
transmission
with
capabili-
ties
for
covering
the
160
through
10
meters
Amateur
bands
as
well
as
many
other
non-ham
band
frequencies
(MARS
coverage,
etc.).
The
T-48
is
a
complete
transmitter
which
may
be
used
for
transceiving
with
the
R-4/R-4A/R-4B
Receiver
or
for
independent
receive/transmit
usage.
A
front
panel
switch
on
the
T-4B
selects
between
transceiving
with
the
R-4/R-4A/R-4B
VFO,
the
T-4B,or
independent
frequency
control.
The
?-48
may
be
crystal
controlled
in
the
transmit
mode
for
novice,
MARS,
DX,
or
net
operation.
The
T-4B
has
CW
sidetone
oscillator,
automatic
transmit/receive
switch-
ing
on
CW,
transmitting
AGO
to
prevent
flat
topping,
plate
meter/relative
output
indicator,
two
crystal
lattice
filters
for
sideband
selection,
receiver
muting,
receiver
antenna
switching,
and
VOX
and
PTT
on
AM
and
SSB,
all
built-in
for
the
optimum
in
operating
convenience
and
economy.
The
T-4B
provides
200
watts
PEP
input
on
AM
and
SSB,
and
200
watts
input
on
CW
for
plenty
of
punch
when
run
barefoot
and
more
than
ample
drive
for
grounded
grid
linear
amplifiers.
Compact
size
and
continuity
of
styling
combine
for eye
appeal
and
con-
venience.
A
speaker
is
built
in
for
use
with
a
companion
receiver.

II. INSTALLATION INSTRUCTIONS
A. UNPACKING
Carefully remove your T-4B from its packing carton and examine it closely
for signs of shipping damage. Should any be apparent, notify
the delivering carrier immediately, stating the full extent of the damage.
Fill out and mail the enclosed registration card so that your warranty will
be effective.
Save the packing material. You may need it later for reshipment or storage.
Inspect the packing material closely before putting it away to be sure you
have not overlooked the accessory hardware packed with the unit.
Be. LOCATION
In general, the location of the T-4B is not critical. However, care should
be taken to insure that space is provided around the unit to allow adequate
air circulation. Extremely hot locations, such as near radiators or heat-
ing units, should be avoided. Do not cover the top of the unit with books,
papers or pieces of equipment or overheating may result.
C. POWER REQUIREMENTS
The T-4B should be used with our Model AC-4 Power Supply. This supply is
designed to supply the proper voltages and currents for this unit from
120/240 V AC 50/60 cycles. The T-4B can also be operated from our Model
DC-4 Power Supply which operates from 12 volts D.C. The DC-4 also supplies
120 V AC to power the receiver.
D. ANTENNA REQUIREMENTS
The T-4B is designed for use with antennas resonant on the operating fre-
quency and having approximate impedance of from 30 to 100 ohms. Although
there are many types of antennas which will meet this requirement, the sim-
plest is a one half (%) wave dipole, center fed with 52 ohm coax. For a
detailed discussion on antennas, we suggest you refer to the ARRL ANTENNA
BOOK or THE RADIO AMATEUR'S HANDBOOK.
Antenna connection to the T-4B is provided at the S0-239 coax connector
located on the rear of the shielded compartment housing the final amplifier
components.
CAUTION: NEVER ATTEMPT TO OPERATE THE T-4B WITHOUT FIRST
CONNECTING TO AN ANTENNA OR 52 OHM DUMMY LOAD
OF SUFFICIENT POWER HANDLING CAPACITY OR SERIOUS
DAMAGE CAN RESULT.

E. RECEIVER MUTING
The
RCVR
MUTE
jack
provides
a
short
circuit
to
ground
on
receive
and
an
open
circuit
on
transmit.
This
jack
can
be
connected
directly
to
the
Mute
jack
on
the
R-4/R-4A/R-4B
Receiver
with
one
of
the
hook
up
cables
provided.
F. RECEIVER ANTENNA SWITCHING
The
T-4B
contains
built
in
receiver
antenna
switching.
Simply
connect
one
of
the
coax
cables
provided
from
the
RCVR_
ANT
jack
on
the
rear
of
the
T-4B
chassis
to
the
receiver
antenna
terminals.
G. ANTI-VOX & SIDETONE
The
Anti-Vox
input
and
CW
sidetone
output
utilizes
the
ANTI
VOX/SIDETONE
jack
on
the
rear
of
the
T-4B
chassis
for
connecting
to
the
receiver
and
speaker.
The
impedance
at
this
point
is
approximately
5,000
ohms.
To
connect
to
the
R-4/R-4A/R-4B
Receiver,
simply
couple
the
ANTI
VOX/SIDETONE
jack
to
the
ANTI-
VOX
jack
on
the
rear
of
the
receiver
chassis
with
one
of
the
cables
provided.
If
the
R-4/R-4A/R-4B
Receiver
is
not
used,
it
will
be
necessary
to
use
a
5,000
ohm
to
4
ohm
audio
output
transformer
between
the
ANTI
VOX/SIDETONE
jack
and
the
speaker
terminal
of
the
receiver.
The
high
impedance
winding
of
the
transformer
should,
of
course,
be
connected
to
the
ANTI
VOX/SIDETONE
jack
and
the
4
ohm
winding
in
parallel
with
the
speaker.
An
alternate
connection
for
this
jack
would
be
to
the
plate
of
the
receiver
audio
output
tube
(a
DC
block-
ing
capacitor
is
provided
in
the
T-4B).
H. R-4 INJECTION
In order to transceive with the R-4/R-4A4/R-4B Receiver, run a cable from the
INJ jack on the rear of the T-4B chassis to the INJ jack on the top of the
R-4 or on the back of the R-4A or R-4B chassis. It will be necessary to .
remove the top cover of the R-4 to gain access to this jack. This cable will
provide both RF and control voltage. (See Figure. #1)
I. MICROPHONE REQUIREMENTS
A
microphone
with
a
wide
and
flat
frequency
response
will
enable
you
to
obtain
peak
performance
from
your
T-4B.
For
good
VOX
(voice
control)
operation,
it
is
desirable
for
the
mike
to
have
a
cardioid
pattern
to
reduce
pick-up
from
the
back
and
sides.
This
enables
you
to
operate
with
higher
receiver
audio
gain,
giving
better
VOX
operation
and
reducing
echoes,
reverberation,
and
noise
pick-up.
Microphones
with
limited
low
or
high
frequency
response
and
with
peaks
in the
voice
range
should
be
avoided.
A
.210
inch
diameter
three
conductor
microphone
plug
(Switchcraft
Type
§-230)
is
provided
with
the
T-4B.
The
microphone
must
be
connected
as
shown
here
for
proper
VOX
and
push-to-talk
operation.
Many
microphones
that
are
furnished
with
a
switch
are
wired
so
that
the
microphone
cartridge
is
open
or
short
circuited
unless
the
switch
is
depressed.
This
function
must
be
defeated
or
VOX operation will be impossible.

$-230 CONNECTOR
MICROPHONE (SWITCHCRAFT)
J. SPEAKER
The T-4B has a built-in speaker. Connection to this speaker is made avail-
able at the jack marked SPKR on the rear of the T-4B.
K. GROUND REQUIREMENTS
The T-4B should be attached to a good earth ground through as short and as
heavy a piece of ground braid as possible for best results. A binding post
is provided on the rear of the chassis for this purpose. (See Rear View,
Page 12).
Le. LINEAR AMPLIFIER CONNECTION
In order to use your T-4B with a linear amplifier, connect as per Figure 2.
Note that if the linear amplifier has negative going transmitting AGC voltage
available, it can be connected to Pin 3 of the power connector to prevent the
linear from flat topping.
For connections to the DRAKE L-4 or L-4B Linear Amplifier, see the L-4 or L-4B
instruction manual.

NOTE:
External connections
on R-4 are not in
same physica! position
as on R-48, Inj jack
ts on top of chassis.
See top ond rear
photos in R-4 instruc-
tion book.
Speaker Cabie
FIG. | CONNECTING THE T-48 TO THE R-4/R-4A/R-4B RECEIVER, AND AC-4 POWER SUPPLY
1-48
ac-4
R-
4A/R-48
LINEAR
NOTE:
External connec-
tions on R-4 ore
not In some
physical position
as on R-4A.
taj Jack ison
top of chassis,
See top and
rear view photos
in R-4 instruc~
tion book.
ae
Coax
Relays
-
On
mony
linear
amplifiers
these
supply
celoys
are
bulit
in.
Accessory
contacts
ca
voltoge
be
used
for
bios
switching.
FIG.
2
CONNECTING
THE
T-48
TO
A
LINEAR
AMPLIFIER.
FOR
CONNECTIONS
TO
DRAKE
L-4/1-48,
SEE L-4/L-4B INSTRUCTION MANUAL

Fie. 3
IAI
SOKO
SRS
aed
Power Cable
Antenne CGabie
Revr
Mute Cable
Anti Vox / Sidetone Oable
To Speaker Voice Coil
A.F. Output Xmfr
CONNECTING THE T-48 TO A RECEIVER OTHER THAN THE R-4, R-4A, R-48
STANDARD OPTION #1
SCREW MOUNTED REAR
FEET REMOVED
INVERTED FRONT FEET
FEET REMOVED FROM REAR OF BASE
OPTION # 2
STUD 10x24 5/8 LONG
SUPPLIED WITH UNIT
FIG. 4 VIEWING ANGLE OPTIONS
8.

III. CONTROL FUNCTIONS
FRONT CONTROLS
1.
FREQUENCY CONTROL - The Frequency control switch determines whether
the T-4B or R-4/R-4A/R-4B controls the transmitting and receiving
frequency.
In SPOT position, low level transmitter stages are switched on and
the receiver is not muted to allow the receiver to be tuned to the
T-4B. In SPOT the T-4B is crystal controlled. During SPOT no sig-
nal is put on the air. yee
In
RCV
VFO/XMIT
XTAL
position,
the
T-4B
is
crystal
controlled
during
transmit
and
the
R-4/R-4A/R-4B
determines
the
receiving
frequency.
In
VFO
position,
the
R-4/R-4A/R-4B
determines
both
the
receiving
and
tr.
transmitting
frequencies
for
transceiving.
In
this
mode,
the
T-4B
XTAL
switch
has
no
effect.
In
the
XTAL
position,
the
crystal
selected
by
the
XTAL
switch
on
the
T-4B
determines
both
the
receiving
and
transmitting
g
frequencies
for
transceiving.
In
this
mode,
the
R-4/R-4A/R-4B
VFO
and
R-4
/R-4A/R-4B
crystals have no effect.
XTALS
-
The
XIAL
switch
is
a
10
position
switch
used
to
select
the
accessory
crystal
that
will
determine
the
T-4B
transmitting
frequency
when
the
FREQ
CONTROL
switch
is in
any
position
except
VFO.
PLATE
-
The
PLATE
control
tunes
the
power
amplifier
Pi-network
circuit
to
resonance
by
varying
the input
capacity.
LOAD
-
The
LOAD
control
matches
the
impedance
of
the
power
amplifier
to
the
impedance
of
the
load
by
varying
the
output
capacity
of
the
Pi-
network
circuit.
METER
-
The
METER
control
is
a
combination
spring
loaded
switch
and
potentiometer.
The
meter
normally
reads
P.A.
Plate
current.
When
the
knob
is
depressed,
the
switch
converts
the
meter
to
read
relative
RF
output
and
when
rotated
it
varies
the
sensitivity
of
the
relative
output
indicator.
Releasing
the
control
allows
it
to
return
to
the
plate current position.
RF
TUNE
-
The
RF
TUNE
control
permeability
tunes
the
driver
grid
and
plate
Pintatcoule
and
the
p:
premixer
output
coils.
The
logging
scale
on
this
control
is
calibrated
from
0
to
10
with
markings
showing
the
approxi-
mate
settings
for
the
160
through
10
meter
Amateur
bands.
For
frequency
frequencies
outside
Amateur
bands,
see
graph
on
Page
24
for
approximate
settings.
GAIN - This control regulates the microphone gain on AM and SSB.
When
the
unit
is
on
CW
or
TUNE,
it
is
used
to
adjust
the
RF
drive
to
the proper
level.
The Gain control is connected so that it regulates VOX sensitivity as
well as the audio drive to the balanced modulator. Since all changes
in level due to the type of mike, how close or loud you talk, etc.,
effect equally the VOX and the audio drive requirements, this elim-
inates the necessity of changing the VOX adjust eontrol, located on
the side of the chassis, once it is set properly.
9,

B.
9.
10.
Since relay operation on CW depends partially on sidetone voltage fed
through the VOX system, the GAIN control must be turned up slightly
on CW to obtain positive relay action.
SIDEBAND
-
This
control
switches
between
either
of
two
2.4
KHz
crystal
filters
for
sideband
selection.
You
will
notice
that
lower
sideband
which
is
marked
with
an
'X'
must
be
used
for
CW
and
AM
operation.
The
FUNCTION
switch
is
also
marked
with
an
"X"
in
these positions.
BAND
-
The
BAND
control
is
a
six
position
switch
used
to
select
the
amateur
band
desired
or
to
switch
the
RF
circuits
to
the
correct
tun-
ing
accessory
frequency
ranges.
The
frequency
range
which
may
be
tuned
for
each
setting
of
the
band
switch
control
is
given
on
the
chart
on
Page
24
FUNCTION
-
The
FUNCTION
switch
is
a
four
position
switch
which
deter-
mines
the
mode
of
output.
WARNING:
-
The
TUNE
position
of
this
switch
automatically
places
the
transmitter
on
the
air. Consideration
should
be
given
to
other
control
settings
as
described
under
''TUNE
UP
PRO-
CEDURE",
to
avoid damage
to
the
final
amplifier
tubes,
and
to
avoid
unnecessary
interference.
SIDE CONTROLS & JACKS
1.
2.
VOX
-
The
VOX
control
is
used
to
adjust
the
gain
of
the
VOX
amplifier
and relay
release
time
on
CW.
ANTI
VOX/SIDETONE
-
Adjusts
the
ANTI
VOX
sensitivity
and
sidetone
out-
.
put
level.
MIC - The MIC jack consists of a .210 inch diameter phone jack of the
three
conductor
variety
to
accommodate
microphones
with
push-to-talk
switches. A mating plug is provided with this equipment.
XTAL - Ten crystal sockets are provided for ten operating frequencies
selectable by the XTAL switch on the front panel. The crystals are
numbered top row left to right, 1 through 5, and bottom row left to
right, 6 to 10. Each socket has an associated trimmer below it
for calibrating the crystal to exact frequency.
REAR CONNECTIONS & CONTROLS
ANT - Consists of S0-239 connector for attaching T-4B to antenna.
RCVR ANT - Connects receiver to antenna through built-in antenna relay.
RCVR MUTE - Provides short circuit to ground on receive and open cir-
cuit on transmit for muting receiver.
ANTI VOX/SIDETONE - Serves as ANTI VOX input on receive and sidetone
output on transmit.
10.

1.
INJ - Serves to couple the T-4B to the frequency controlling circuits
of the R-4/R-4A/R-4B Receiver if transceive operation is to be used.
KEY JACK - This normally closed jack provides a means to connect a
key for CW operation. On other modes the key bus is grounded so key
can be left in key open position.
POWER CONNECTOR - A 12 conductor socket is provided for connection to
the AC-3/AC-4.or DC-3/DC-4 Power Supply. A matching plug is provided
on the power supply.
GROUND - A screw and nut are provided on the rear of the unit for at-
taching the ground lead.
VOX DELAY - A potentiometer is used to provide a variable time
delay for VOX drop out.
INSIDE CONTROLS
CARRIER BALANCE - The CARRIER BALANCE control is located on top of the
chassis, near right rear, and serves to balance the balanced modulator.
This is a planetary drive potentiometer requiring 10 turns for complete
travel.
11.

neoeee
SIDEVIEW
FIGURE 5
ANTENNA
POWER
GROUND
REAR VIEW
FIGURE 6
12.

IV. TUNING PROCEDURE
WARNING:
UNDER
NO
CIRCUMSTANCES
SHOULD
OPERATION
OF
THE
T-4B
BE
ATTEMPTED
UNLESS
IT
HAS
BEEN
CONNECTED
TO
A
PROPER
AN-~
TENNA
OR
A
DUMMY
LOAD
OF
SUFFICIENT
POWER
HANDLING
CAPACITY.
BIAS ADJUSTMENT
Before
any
type
of
operation
is
attempted,
it
will
be
necessary
to
set
the
power
supply
bias
to
the
correct
value.
Proceed
as
follows:
1.
Turn
T-4B
on
by
rotating
gain
control
clockwise
until click
is
heard
and
set
gain
at
minimum
(extreme
counter-clockwise
position).
2. Set SIDEBAND switch on Upper.
3. Set FUNCTION switch on Tune.
4,
Adjust
AC-4
bias
control
for
a
reading
of
.07
on
the
plate
amperes
meter.
This
is
1
marks
below
.1
on
meter
and
is
the
calibration
mark
above
the
horizontal
line.
2
5.
Return
FUNCTION
switch
to
SSB
position.
This
completes
bias
adjust-
ment.
TUNE UP ON DESIRED BAND
DO
NOT
ALLOW
THE
PLATE
CURRENT
TO
EXCEED
.07
AMPS
FOR
MORE
THAN
5
OR
6
SECONDS
IF
THE
PLATE
CONTROL
IS
NOT
TUNED
FOR
PLATE
CURRENT
DIP
OR
MAXIMUM
RF
OUTPUT.
FAILURE
TO
OBSERVE
THIS
WARNING
WILL
RESULT
IN
RAPID
FINAL
AMPLIFIER
TUBE
DE-
TERIORATION
DUE
TO
EXCESSIVE
PLATE
DISSIPATION.
.
Incorrect
setting
of
RF
TUNE
may
cause
illegal
output
from
transmitter
on
frequencies
other
than
intended.
Always
preset
the
RF
TUNE
control
before
proceeding
with
other
steps
in
tune
up
procedure.
Preset controls as follows:
1, BAND switch to desired band.
2.
XTALS
switch
set
on
crystal
for
desired
frequency.
When
operating
transceive,
set
the
R-4/R-4A/R-4B
VFO,
Band
Switch,
Preselector
and
Xtals on the desired frequency.
3. GAIN fully counter-clockwise.
4. LOAD fully counter-clockwise.
5. SIDEBAND either upper or lower.
6. FUNCTION switch to SSB.
7.
RF
TUNE
to
center
of
amateur
band
in
use
or
use
graph
on
Page
24
for other frequencies.
Rotate
the
FUNCTION
switch
to
the
TUNE
position
and
advance
the
GAIN
eontrol
approximately
1
division.
Adjust
the
RF
TUNE
control
until
the
plate
current
is
about
.15
amps
and
quickly
tune
the
PLATE
control
for
a
plate
current
dip. (See
above
warning).
Readjust
the
RF
TUNE
control
for
peak
plate
current,
making
sure
that
the
PLATE
control
is
still
adjusted
for
plate
current
dip.
Then
advance
the
GAIN
control
until
the
plate current no longer increases.
13.

When tuning up in transceive, the R-4/R-4A/R-4B preselector and the T-4B RF
Tune must be adjusted for peak plate current. The preselector can be set
later to the correct position for maximum sensitivity while receiving.
Depress the METER control and rotate it for a mid scale indication on the
meter. This control converts the plate amperes meter to a relative output
indicator and varies its sensitivity.
Alternately adjust the LOAD and PLATE controls for maximum RF output. If the
meter reads off scale, simply reduce its sensitivity by turning the METER
control counter-clockwise.
When maximum output has been reached, release the METER control and readjust
the PLATE control slightly to maintain the plate current dip. At this point
the meter should read between .25 and .35 amps. Keep the LOAD control peaked
for maximum as read on the REL-OUTPUT METER. A setting that is not peaked
could cause excessive plate dissipation and TVI. NEVER use the LOAD control
to reduce the T-4B output power.
The above tune up procedure should be completed as quickly as possible and
the FUNCTION switch returned to the SSB position.
The transmitter is now ready to operate in any mode at the frequency to which
it was tuned with the exception of the gain control setting which varies with
the mode used.
C. CARRIER BALANCE ADJUSTMENT
The CARRIER BALANCE control is factory adjusted and should require a minimum
of resetting. The proper setting of this control can be checked using the
following procedure:
After tuning up as described above, set the SIDEBAND switch on "X", Gain fully
counter-clockwise, and FUNCTION switch to CW. Either close the push~to-talk
line with a short or by plugging a microphone into the jack and pressing the
push-to-talk switch. Depress the REL-OUTPUT meter control and rotate it full
clockwise. Adjust the CARRIER BALANCE control and C-6 for a minimum meter
reading. Return the FUNCTION switch to SSB. This completes the adjustment.
' D. TRANSCEIVE ALIGNMENT
The carrier oscillator is set at the factory and unless you have good reason
to believe it to be off, it would be best to assume it to be on frequency.
The carrier oscillator can be checked for alignment by following the instruc-
tions on the next page.
14,

TRANSCEIVE ALIGNMENT (continued)
Set the controls as follows:
CONTROL or
SWITCH
a
feo ET:
at 12 o'clock
a
a
oc
SIDEBAND Set to the sideband
that gives the loudest
"canary" sound.
PRESELECTOR Both R-4B, R-4A, R-4 and T-4B Preselectors
should be set to about 6.5 and both adjusted
for the loudest "canary" sound from the
speaker,
. T-4B-
R-4, R-4A, or R-4B
Adjust C61 in the R-4/R-4A/R-4B until the "canary" sound slows down to
only a few chirps a second and then zero chirps a second and all that
is heard is a single tone.
15.

VY. OPERATION
In the following discussion concerning operation on various modes, it is as-
sumed
that
the
T-4B
has
already
been
tuned
up
on
the
desired
band
as
described in the Tuning Procedure.
A. VOICE CONTROLLED & PUSH-TO-TALK OPERATION ON SSB
Preset the controls. as follows:
SIDEBAND----------------- Desired sideband (usually lower on 80 and 40
and upper on 20, 15 and 10)
FUNCTION SWITCH---------- SSB
GAIN--------- nen nnn ne Fully counter-c lockwise
VOX GAIN----------------- (Forward side control) fully clockwise
ANTI-VOX----------------- (Rear side control) fully counter-clockwise
VOX DELAY---------------- (Right rear enter) fully clockwise
The receiver should be operating normally on the same band except that the
audio gain control must be turned all the way down.
Talk into the mike at normal voice level and increase the GAIN control until
the plate meter kicks to about .15 amps. Reduce the VOX GAIN until a point is
reached where the relay drops out too frequently to suit you. Then advance it
just enough to prevent this. Increase the receiver audio gain control for nor-
mal volume and adjust the ANTI VOX clockwise just high enough to prevent cy-
cling between transmit and receive. Adjust the VOX DELAY potentiometer for
desired holding time.
For Push-to-Talk operation, be sure the switch on your microphone is properly
connected as described under Installation Instructions. It may then be de-
pressed at any time, thus over-riding the VOX system, The transmitter will
.remain on and the receiver muted as long as the switch is down. If you do not
desire the VOX to function at all, turn the VOX control fully counter-clockwise.
B. CW OPERATION
Set the controls as follows:
SIDEBAND---------------9--"-- On "X'' (lower)
FUNCTION SWITCH-------<---<-- X-CW
GA Ne n- 2a ne nn enn nee nee n- 12 o'clock
VOX GAIN=------- ene n eee nneen- Fully counter-clockwise
VOX DELAY---2------ e-em erne-- Fully clockwise ~
To provide an audible tone when transceiving with a station on your trans-
mitter frequency, the T-4B output frequency in CW mode is shifted 1 KHz
lower than what the controlling VFO or crystal indicates. Therefore, set the
controlling VFO 1 KHz higher than the desired transmitting frequency. When
operating crystal control, the crystal should be selected as in G. CRYSTAL
CONTROLLED OPERATION, Paragraph 2, Page 21.
16.

Plug
a
key
into
the
KEY
jack
on
chassis
rear
and
leave
in
key
up
condition.
If
an
electronic
keyer
is
used,
connect
it
for
grid
block
keying.
If
the
sidetone
is
to
be
heard
on
transmit,
the
anti-vox
circuit
must
be
connected
as
outlined
under
Installation
Instructions.
To
transmit,
close
the
key
and
advance
the
VOX
GAIN
control
until
the
trans-
mitter
remains
on
transmit.
Adjust
the
VOX
DELAY
control
for
desired
"hold-in"
time
when
the
key
is
released.
Due
to
different
operating
conditions
between
TUNE
and
CW,
the
power
output
may
be
lower
in
the
CW
position
for
a
given
setting
of
the
GAIN
control.
In
CW,
with
the
key
down,
advance
the
GAIN
control
clockwise
just
below
the
point
at
which
the
plate
current
no
longer
increases.
Depress
the
METER
con-
trol,
and
adjust
the
LOAD
control
for
maximum
as
read
on
the
REL-OUTPUT
METER.
Advance
the
ANTI-VOX/SIDETONE
control
on
the
side
of
the
chassis
until
the
sidetone
reaches
the
desired
volume.
The
T-4B
uses
automatic
transmit-receive
keying.
This
means
that
it
will
automatically
transmit
when
the
key
is
depressed
and
will
remain
in
the
transmit
condition
through
keying
at
all
normal
speeds.
It
will
return
to
the
receive
condition
when
the
key
is
released
for
a
brief
period.
If
the
"hold-in"
time
is
excessive,
decrease
the
setting
of
the
VOX
DELAY
control.
Manual
transmit-receive
switching
can
be
accomplished
by
connecting
an
external
switch
(i.e.
foot
switch)
from
the
Push-to-Talk
terminal
of
the
MIC
jack to ground.
C. AM OPERATION
The
T-4B
uses
controlled
carrier
screen
modulators
for
AM.
This
holds
the
unmodulated
carrier
input
power
to
a
few
watts
but
allows
up
to
200
watts
PEP
input
on
voice
peaks.
For
AM
operation
set
FUNCTION
switch
to
X-AM
and
SIDEBAND
switch
to
xe
2.
While
talking
into
the
mike
at
normal
voice
level,
increase
the
GAIN
control
until
the
plate
meter
kicks
to
.15
amps
on
peaks.
Care
should
be
taken
not
to
exceed
this
level
as
there
is
no
AGC
on
AM.
If
voice
control
is
to
be
used
the
VOX
and
ANTI-VOX
controls
should
be
adjusted
as
outlined
under
SSB
Operation.
If
Push-to-Talk
is
to
be
employed
and
you
do
not
want
the
VOX
to
function
at
all,
turn
the
VOX
control
fully
counter-clockwise.
The
T-4B
output
frequency
in
AM
mode
is
shifted
1
KHz
lower
than
what
the
controlling
VFO
or
crystal
indicates.
Therefore,
set
the
controlling
VFO
1
KHz
higher
than
the
desired
transmitting
frequency.
When
operating
crystal
control,
the
crystal
should
be
selected
as
in
G.
CRYSTAL
CONTROLLED
OPERATION,
Paragraph 2, Page 21.
D. SPOTTING
The
SPOT
position
of
the
FREQ.
CONTROL
switch
is
used
to
bring
the
receiver
to
the
same
frequency
as
the
T-4B
when
separate
control
is
being
used.
In
this
position,
the
receiver
is
operative
but
not
connected
to
the
antenna.
The
17.