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