Hallicrafters HT-32A Training manual

a | oes 2 eee
the hallicratters co.
MANUFACTURERS OF ELECTRONIC EQUIPMENT, CHICAGO 24, U.S. A.
%

092-i03923
Figure
I.
Hallicrafters
Model
HT-32A
Transmitter/Exciter
SECTION I
GENERAL
1-1, DESCRIPTION,
The Hallicrafters Model HT-32A Transmitter/
Exciter is the ultimate in design of self-contained trans-
mitting equipment. This twenty-tube precision built
transmitter/exciter is capable of SSB (single sideband
with suppressed carrier), DSB, and CW transmission
in the 80, 40, 20, 15, and 10 meter bands, This unit
canrepres ent the complete transmitting complement of
any amateur station. The only requirements for im-
mediate"'on the air" operation area 50-ohm terminated
antenna system, key or microphone, and AC power
source.
1-2. SCOPE OF OPERATION.
This
unit
may
be
utilized
as
a
complete
self-
contained
transmitter,
or
as
an
exciter
for
a linear
power
amplifier
such
asthe
Haliicrafter
Model
HT-33A.
if
other
linear
amplifiers
are
employed,
they
should
be
capable
of
supplying
a
50-ohm
termination
to
the
driver
output
to
utilize
the
full
capabilities
of
the
HT-
32A
Transmitter/Exciter.
Maximum
power
output
ratings
of
the
HT'-32A
Transmitter
/Exciter
are:
SSB,
70-100
watts
P.E.P.
(peak
envelope
power);
cw
70-100
watts;
and
DSB
17-25
watts
(carrier
power).
Prominent
features
of
the
HT-32A4
Transmitter/
Exciter
are;
@ New high frequency crystal sideband filter -
rejection 50 db. or more.
® Bridged-tee sideband modulator.
@ C.T.O, direct reading in kilocycles to less
than 300 cycles from reference point.
144 watts plate input (P, E. P. two-tone).
Five band output (80, 40, 20, 15, 10 meters),
Unwanted sideband down 50 db, or more.
Distortion products down 30 db. or more
Sie Biel el Poets anne We
Carrier suppression down 50 db. or more,
1-3, T.V.1, (Television Interference) SUPPRESSION.
The HT-32A Transmitter/Exciter has been designed
and constructed to suppress spurious radiations that
may cause television interference. The TVI problem
was given full consideration in the design of every cir-
cuit as well as in the selection and layout of parts.
Adequate filtering has been provided for control cir-
cuits aud AC power lines. Components were specifi-
cally selected to avoid undesired resonances and ar-
ranged to prevent parasitic oscillation,
Another important T. V.I. proofing feature is em-
ployed in the output coupling circuit of the final ampli-
fier, The tuned output circuit is api network that has
inherently excellent harmonic suppression ability. The
unique design of this network is such that the conven-
tional loading control is unnecessary and only the final
tank tuning need be adjusted. The pi network is cor
nected to a coaxial connector and permits the use of
any antenna system having a transmission line im-
pedance of SO ohms, In additian to these fartare In
et ed he ee, eT MAL EARLE RL ALFA LAY LA saws ¥ ain
stalled precautions, a commercial 50-cohm low pass
TVi filter, which connects between the antenna andthe
transmitter /exciter output, can be used,

The Model HT-32A Transmitter/Exciter, as re-
ceived from the factory, has had every advantage of
Hallicrafters advanced engineering to minimize tele-
There are, however, some tynes
of TVI that cannot be prevented within the transmitter
itself. For example, when a television receiver is
located in the immediate vicinity of the transmitter/
exciter itis entirely possible that a fundamental signal
will reach the input grid of the receiver in sufficient
strength to cause a slight amount of interference. in
vision interference.
such cases, it will be necessary to install a filter or
trap at the television receiver to attenuate the trans-
mitter's fundamental signal. if the interlering signal
does not enter the television receiver through the an-
tenna, special shielding or filters on the TV receiver
may be necessary. For a more complete discussion
of measures that may be used to handle these special
television interference problems, refer to the ARRL
HANDBOOK.
SECTION I!
INSTALLATION
2-1. UNPACKING.
After unpacking the HT-32A Transmitter/Exciter,
examine it closely for any possible damagt which may
have occurred during transit, Should any sign of dam-
age be apparent, fileaclaimimmediately withthe car-
rier stating the extent of damage, Carefully check ail
shipping labels and tags for any speciaj instructions
before removing or destroying them,
2-2, LOCATION.
Although the Model HT-32ATransmitter/Exciter is
provided with 4 built-in power driven fan for cooling
purposes, avoid excessively warm locations such as
those near radiators andheating vents. The unit should
be placed ina location that provides adequate space
around it, permitting free circulation of air through
the cabinet openings.
2-3. POWER SOURCE.
The HT-32A Transmitter/Exciter is designed to
operate on 105 to 125 volt, 50-60 cycle AC current,
power consumption is 375 watts,
JIMPORTANT: If in doubt about your power
Source, contact your local power company
prior to inserting the power cord into an
AC power outlet, Plugging the power cord
into the wrong power source can cause
extensive damage to the unit, requiring
costly repairs.
2-4. FRONT PANEL CONNECTIONS (See Fig. 1).
Receptacies are provided on the front panel of the
HT=32A Transmitter/Exciter for the following pur-
poses:
2-4-1. MIKE RECEPTACLE.
The Model HT-32A Transmitter/Exciter is designed
to operate with a high impedance communications type
microphone, The microphone cable should be fitted
with an Amphenol type 80-MC2M connector and should
be wiredas shown in the schematie diagram, Figure 14,
Tf the microphone used does not have a push-to-talk
switch, the switch circuitry may be disregarded and
the microphone connected between pin 1 and the shield
(connector body),
2-4-2, KEY JACK.
This standard two-conductor phone jack is provided
on the front panel for hand key or ''bug" operation. The
KEY jack accepts a general purpose standard two-con-
-o°
ductor phone plug, Connections ior keying are also
provided on the Control Outlet receptacle on the rear
panel, See paragraph 2-5-2-2. Wire the plug so that
the key base is connected tothe sleeve of the plug which
is also at chassis ground. *
2-4-3. MONITOR JACK.
This standard two-conductor phone jack: permits
yoice controlled headphone reception in the VOX mode
of operation. The MONITOR jack accepts a general
purpose two-conductor phone plug. inserting the plug
of a headset into this jack will automabicay cut off the
receiyer speaker connected as instructed in
paragraph 2-5-2-4,
receiver sneaker whenit is
2-5. REAR CHASSIS CONNECTIONS {See Fig. 2).
Sockets are provided on the rear of the HT-32A
Transmitter/Exciter for the following purposes:
2-S-1. RF OUTPUT,
This is &2coaxial connector which connects the HT-
32A Transmitter/Execiter to the antenna system or a
linear amplifier. The connecting cable (52 ohm coax, )
should be fitted with an Amphenol type 83-15P connector
or its equivalent. The selection of the type of antenna
and coupling will depend upon the frequencies used and
the purpose of operation, Refer tothe ARRL ANTENNA
HANDBOOK for detailed infor mgtion concerning trans-
mitting antennas.
2-5-2. CONTROL OUTLET.
An eleven pin socket is provided at the rear of the
chassis to connect the HT-32A Transmitter /Exciter
into your control system. The mating connector for
this socket isan Amphenol 86-PMil. ‘The instructions
which follow may be modified to suit your particular
needs,
2-5-2-1, ACCESSORY RELAY CONTACTS
{Pins 6 and 7).
Two extra relay contacts working against chassis
ground (Relay arm grounded, contacts connected to
pins -6 and 7) are available for applications where a
closed circuit tochassie is required in either the trans-
mit or receive condition, When transmitting pin6is at
chassis groundandpin 7 is opencirevit, During stand-
ioe SAUER Le Sets a pes SUPT ell oe
by or receive periods, pin 6 is open circuit and pin 7
is atchassis ground. See Figure 3 for a typical appli-
catiou,

GROUNO-RECEIVE { RELAY _7 RELAY CONTACTECPEN CIRCUIT-RECEIVE -
OPEN
CIRCUIT~TRANSMIT
[CONTACT
;
|
GROUND
-
TRANSMIT
Biot
5
-|OO¥ BIAS (HIGH IMPEDANCE)
KEY CONNECTION ee [
9 .
IF PANEL JACK
IS NOT USED GROUND
$0 OHM POWER
FSR JACK RF OUTPUT corp
er — © @ woe
CONTROL
OUTLET
To FUSE 4AMPS
RECEIVER | GROUND To SPOT $LO-9LO
OUTPUT
vOx
RELAY
CONTACTS AC OUTLET
if CONTACT RATING 2 AMP. MAX,
ro DAMP @ ey {ACCESSORY}
SPEAKER 1 crounp «/_—_.___]
Figure 2. Rear Chassis Connections
8x~-100
$X~101
TO GRID RETURN
OPERATING
RECEIVE
STAND-BY
Blas
s0JUST
SWITCH IN
STAND-BY
POSITIGN
VOX
RELAY
STAND-8Y
PLATE
SHOWN IN RECEIVE TYPICAL CURRENT ADJUST
FRONT
POSITION
POWER
4MPL.
PANEL
(INTERNAL
TO
SET}
1 Wak
NC me J RF GAIN NOTE:
=
SET FOR DESIRED LEVEL UNITS MUST BE BONDED TO COMMON
USE
HEACPHGNE
JACK
:
WHEN
MONITORING
CW
GROUND
SYSTEM
FOR
OC
RETURN.
TRANSMISSION
WHEN RECEIVER 15 WIRED
FOR ¥OX OPERATION
—
1 DAS RECEIVER
H TO ANTENNA
| &——o— me TO TRANSMITTER
PN exrenuan ANTENNA
CHANGE OVER RELAY
usar
ART
Sti: ce my
GUPPLICUS
NOTE:
SAFETY INTERLOCK FEATURE
MAYSE USED iF ANTENNA RELAY
HAS EXTRA CONTACTS.
To +300 ve ¥OX RELAY
RY!
Lf
i
i
|
TO PLATE OF |
|
|
TG FINAL AMPL CONTROL
RELAY TUBE (GENERALLY BAS LEVEL CHANGE]
VITB
TO EXTERNAL
| POWER SOURCE
| __ _I
SEEanianieantnenieneeteetaenen
ost. 505 7a5
Figure 4, Control Outlet Relay Connections
4.

2-5-2-2, KEY (Pins 8 and 9}.
For CW operation, the hand key or “bug” is con-
nected to pins 8 and 9 of the control outlet. Pin 9 is
internally grounded in the unit. When the key is up,
cutoff bias is maintainedat the secondand third mixer
stage. Closing the key removes the cutoff bias pro-
viding signal excitation to the succeeding RF amplifier
Stages, A key jack is also provided at the front panel
for those who prefer a panel connection for the key.
2-5-2-3. ANTENNA RELAY (Pins 2, 3 and 4).
An external antenna change-over relay may be em-
ployed by utilizing pins 2, 3, and 4 on the control out-
let. These pins are connected internally to insulated
contacts on the VOX RELAY of the HT-32A Trans-
mitter/Exciter. Figure a illustrates typical con-~
trol outlet. During periods of transmission the vOX
relay connects pins 24nd 3 enabling the external power
source to activate the external antenna change-over
relay, Forexternal applications where anopen circuit
is required when transmitting, pins 3 and 4 may be
used, The voltage required of the external
source is dependent upon the type change-over relay
used. A coaxial type relay for 50-ohm transmission
line impedance is recommended. Where pins 2, 3,
and 4 areused to switch external equipment loads, the
load current should be limited to one ampere.
power
2-5-2-4. RECEIVER AUDIO (Pins 9 and 10}
AND SPEAKER (Pins 1 and 11).
Connect the audio output of the station's receiver di-
rectly to pins 9 and 10 of the control outlet, (Pin 9 is
ground or chassis side.) Comect a 2 watt resistor
across the receiver audio output to maintain a load at
ali times. The receiver speaker is connected directly
to pins land 11. (Pin 1 is ground side.) Connecting
the receiver and speaker in this manner prevents the
actuating of the HT-32A transmitter /exciter VOX cir-
cuit by incoming atdio signals from the receiver and
also disconnects the receiver output to the speaker
when the HT-32A Transmitter/Exciter is on the air,
Use an i8-ohm 2 watt resistor for 3 to 8 chm voice
coil impedances or 1500 ohm 2 watt resistor for 500-
600 ohm outputs.
2-5-2-5. BIAS (Pins 5 and 9}.
impedance b iy 7 t
with pin 9 used as the return or ground comiection.
The bias is fixed at approximately -100Vregardiess of
the modeof operation of the transmitter. An external
relay may be used with the fixed bias provided at pin
5 to obtain the desired application, Note that the bias
nea and not intended as 2a "hard"
ana not intended Rates UE
p th a 2 5 a
a
- tt
pe
al :
fa a
Ln
= “-
a
-5-
bias source for fixed bias applications in power ampli-
fiers.
2-5-3, FS JACK,
This is a standard 3-circuit jack that brings out
the keying circuit required for frequency shift keying
used in teletype transmission, For a more detailed
explanation refer toNOTES on page 23, The FSK jack
accepts the standard size general purpose three-con-
ductor phone plug.
2-5-4. ACCESSORY POWER OUTLET,
A standard AC receptacle is provided at the rear
apronas aconyenient source of 117V AC power for the
antenna relay or Similar light duty loads. Do not use
this outlet for heavy loads such as a power amplifier,
2-6. PHONE PATCH INPUT.
While this connector is not located on the rear apron,
a
its connecting cable will be fed through one of the rear
cabinet vents, The receptacle is located on the side-
band generator unit in the upper right hand corner of
the deck near the microphone input connector. The
receptacle is a standard "phono" type of jack used on
record players for shielded audio cables, The input
impedance is 500-600 ohms, and the signal level re-
quired for maximum SSB power or 100% AM modulation
is a functionof the AUDIO LEVEL control setting, and
runs approximately 4 millivolts at the full clockwize
position, At reduced sensitivity settings of the AUDIO
LEVEL control, demanded by the output of the oper-
ator's microphone, the phone patch input level for maxi-
mum transmitter output will be proportionately higher.
2-7. ADDITIONAL COUPLING FOR
CALIBRATING SIGNAL,
Most instaliations will not require additional mea-
sures to couple the receiver to the transmitter for an
adequate calibrating signal level. However, there are
Situations where more coupling may be desired. A
phone tip jack has been provided at the topof the shield
over the final amplifier tubes to cope with such situa-
tions. With this confignration the signal level is ade-
quate So that the capacity coupling between the jack,
final tank capacitor, and tube caps will provide more
than enough coupling if a wire lead witha phone tip
soldered to it is used to couple the receiver to the
transmitter, The phone tip is merely a convenient ‘way
of anchoring the coupling lead securely to prevent its
accidently coming into contact with the amplifier com-
ponents
inside
the
shield
compartment.
The
receiver
f the coupling lead may be connected to the re-
ceiver antenna terminal or may be brought into close
proximity of the antenna terminal as determined by
trial,
aI Moe I Te me
SE MEST

SECTION Iil
FUNCTION OF OPERATING CONTROLS
3-1. FUNCTION.
The FUNCTION control is afour position rotary
Switch which selects CW, DSB, UPPER or LOWER
SIDEBAND type of transmission as desired by the oper-
ator, An analysis of the FUNCTION switch operation
is given in paragraphs 4-4, 4-5, and 4-6,
3-2. OPERATION.
This control is a five position rotary switch which
turns the power to thetransmitter onor off, places the
transmitter incalibrate operation or selects the mode
of operation (VOX or MOX). The "CALIBRATE" po-
sitionis used in conjunction with the CALIBRATE LEV-
EL control. (See paragraph 3-11).
The "MOX" position energizes the transmitter con-
trol relay to the transmit position, This position of
the OPERATION switch is used when manual control
of transmission is desired, Return the switch to the
"STANDBY position during receiving periods,
In the “CALIBRATE” position, the HT-32A Trans-~
mitter /Exciter control relay (VOX RELAY) is de-en-
ergized, permitting normal receiving operation with an
antenna change-over relay (if used)in the receiver po-
Sition, With the receiver inoperation the transmitter
signal can now be monitoredand the signalleyel in the
receiver controlled withthe CALIBRATE LEVEL con-
trol. See paragraph 3-11.
Inthe "PTT-VOX" position, the transmitter control
relay may be operated by voice energy from the micro-
phone. The relay tube is biased to cut-offand will not
energizethe VOX RELAY until signal excitation is re-~
ceived from the andio amplifier and vox amplifier
stages, When push-to-talk operation is desired, turn
the VOX sensitivity control fully counterclockwise and
then control the transmission with the microphone
switch,
3-3. DRIVER TUNING.
This control is a variable capacitor mthe VFO mixer
plate, and driver plate circuits, and will resonate the
Pavet ttc wainthea Of AO 9M Th ans TH
eirenits to a Lea ene fli bale UL “EMS phe) iu &. a
ay Ae > "4 r da av
mer fw
Sih Webs Lis attiy Lai
meter bands,
3-4. BAND SELECTOR.
The BAND SELECTOR control is a five position ro-
tary switch which selects the proper combination of
tuned circuits and stages for the desired frequency
band. It also selects the correct crystal oscillator
(4.95 or 13.95 MC) to produce the desired sideband
when the FUNCTION switch is set at either "UPPER"
or "LOWER SIDEBAND".
3-5. FINAL TUNING.
This control is a variable capacitor in the final am-
-7-
plifier tank circuit and wili resonate the circuit to the
operating frequency of the selected band. The dial
calibrations permit presetting the control roughly dur-
ing tune up.
3-6, FREQUENCY.
The FREQUENCY control is a variable capacitor
which sets the VFO frequency. The VFO covers the
frequency range 5,000 kilocycles to 5,500 kilocycles.
With mixing circuits, the VFO will set the HT-32A
Transmitter/Exciter to the desired operation fre -
quency as indicatedon the dial inany of the five bands.
Each minor marker on the skirt of the FREQUENCY
control is equivalent to approximately 200 cycles onal}
bands.
This is a mechanical brake which can be adjusted
either to Lock or apply drag to the FREQUENCY con-
trol to ayaid accidental rotation of the control during
operation.
3-B. AUDIO LEVEL.
This control is apotentiometer connected in the grid
circuit of the third audio amplifier stage and adjusts
the amount of audio drive to the "bridged-T" balanced
modulator. It has sufficient range to permit adjust-
ment for any high level crystal microphone or low Level
dynamic microphone normally used for voice com-
munications,
3-9. RF LEVEL.
The RF LEVEL controlis apotentiometer inthe grid
bias circuitof the 9MC amplifier tube to adjust the gain
of the 9 MC amplifier. On DSB and CW, the amount of
carrier in the output signal is determinedby the setting
of the RF LEVEL control,
This is ameter sensitivity control which per mits the
operator taset the meter at maximum deflection (0DB)
for desired output Level (between approximately 1/4
power and full power) when establishing proper drive
levelsin the HT-324 Transmitter/Exciter. (See LE Y-~
EL INDICATOR METER, paragraph 3-12).
3-11. CALIBRATE LEVEL.
The CALIBRATE LEVEL control provides a low
level adjustment of the transmitter output for SSB, DSB,
or CW operation when the OPERATION control is set
at CALIBRAT&. The CALIBRATE LEVEL control is
normally set to provide the desired signal level in the
station receiver for monitoring purposes and need not
be changed except possibly when changing bands. For
CW or DSB work a carrier signal is obtained for ''zero
beat" frequency setting. On SSB a sideband signal is
obtained when talking into microphone to "talk onto fre-
quency", If the zero beat method is preferred by the
sideband operator, the FUNCTION control is switched

to DSB to obtain a carrier for calibration purposes
then switched back to the desired sideband before going
on tbe air, _Note that o DSB | or cw the @ preset RF
2 a | whe aml
>
on
wok hw Lo ols he
16 To Oe
The LEVEL INDICATOR METER indicates the out-
put of the HT-32A Transmitter/Exciter in DB below
hO DR roeferenca, enahling the adinetment of the HT-
324A Transmitter/ Exciter. for correct output (drive
level required for a linear amplifier‘or approximate
rated output for "barefoot" operation), Tuning of the
transmitter has been simplified by the design of the
front panel meter circuit. The meter scale is com-
pressed to enable low-level signals tonroduce ausable
indication, yet strong signals do not drive the meter
pointer off scale, This feature gives the meter a wide
usable dynamic range which is not possible to obtain
with a linear scale, The desired amount of compres-
sion may be obtained by adjusting the METER COM-
PRESSION control on the front panel. The output
reading on the LEVEL INDICATOR METER can be
shifted to readfull scale ("0"DB) down to approximate-
Tee PLA Wf Fal neawaw ane nee Leeral halon ¢hiac roafaranna
Ly 4/2 OL ture POWCED aa any 2OVCL GOLUW Tuib ACL Cie
can easily be read on the meter. A log of METER
COMPRESSION control settings, for normal output into
loads of controlled and reproducible characteristics,
will aid in re-establishing proper drive levels and
determining the proper operation of the unit, The log
shonld be recorded at various frequencies and modes
of operation,
To monitor carrier suppressionfor SSB operation,
set the METER COMPRESSION contro} to read zero-DB
reference on the meter at the maximum sideband out-
put (single tone), and read carrier level directly when
the audio excitation is removed, Note that the MOX
mode of operation must be used for this test, since on
VOX operation the transmitter is disabled between
voice controlied transmissions by the operation of the
VOX relay.
SECTION IV
TUNING PROCEDURE
4-1. GENERAL.
The tuning procedure for the Model HT-32A Trans-
mitter/Exciter has been simplified by design as much
as possible to permit rapid adjustment by the operator.
This does not mean, however, that atransmitter, com-
mercial or home-built, may be operated successfully
when only roughly adjusted. A clean signal from any
transmitter reqttires good operator technique.
Two mis-tuning conditions onthe HT-32A Trans-
mitter/Exciter are possible, neither of which can be
accidentally used on the air. These undesired signals
are visible on the output meter due to the extreme
range of levels handledby the metering circuit and are
60DBor more below fundamental output when the trans-
mitter is correctly tuned up.
1, On the 15-meter band the undesired signal will
appear when the DRIVER TUNE control is set
outside itsnormal tuning range, approximately
0 to 1 division on the dial. Note that its level
cannot be increased on AM or CW with the RF
LEVEL control or driven by speech input on
SSB, hence may be identified in this manner.
On the 10-meter band the undesired signal will
appear when the DRIVER TUNE control is set
outaide its normal tuning range. For example,
when tuning the 29 MC to 29.5 MC segment of
the 10-meter band, the DRIVER TUNE control
willnormally tune up around 4 onthe dial while
the unwanted signal tunes up at around 2 divi-
sions on the dial, Here againit is identifiedby
the fact that its level cannot be increased on
AMor CW withthe RF LEVEL control or driven
on SSB with speech input,
4-2, LOAD.
Connect a 50-chm non-reactive load to the R.F.
OUTPUT connector on the HT-32A Transmitter/Ex-
citer. This impedance may be an antennaor a proper-
ly adjusted linear amplifier. A 50-ohm non-reactive
loadof at least 100 watts dissipation capabilities is re~
eee ee es ee os es eee ed
Quis 6a (0 f2ancde tue full power ouUTput,
4-3. INITIAL CONTROL SETTINGS.
Set the front panel controls to their starting positions
as outlined below.
OPERATION ........ wee . STANDBY (Power on)
FUNCTION 2... ccc cece ee een ee en eceree . DSB
AUDIO LEVEL ...... ccc e cesses eee ce cer cetae . 0
RF. LEVEL oo. cece ccc eee et ees neee seas 0
METER COMPRESSION .....00ceeceees sees 5
CALIBRATE LEVEL ....-.cscceeceeenvecerees 0
DRIVER TUNING ,........- CENTER OF ROTATION
FINAL TUNING......... -DESIRED BAND SEGMENT
BAND SELECTOR ..... eeeteeeeees DESIRED BAND
FREQUENCY.......-.-.+...DESIRED FREQUENCY
4-4, CW TUNING.
The tuning procedure for CW operation will be
presented first since AM (DSB) and SSB tuning pro-
cedures are modifications of that required for CW
operation,
re
he tuning procedure for CW operation isasfollows:
1. Set the OPERATION switch at MOX; FUNCTION
switch at DSB,
ro ae |
an nal amplifier stages with
d FINAL TUNE controls
for maximum meter deflection. Advance the RF
LEVEL control slightly, if necessary, to obtain
reasonable meter readings for tune up. Since
these tuned circuits, as in any transmitter,
affect transmitter performance, ALWAYS
TUNE FOR MAXIMUM OUTPUT.
Set FUNCTION switch at CW and close key.

Advance the RF LEVEL controi slowly while ob-
serving the output meter. When feeding a
dummy or anantenna load, set thecontrol at a
point where further rotation does not cause an
appreciable increase inthe meter reading. This
is saturation output; operate slightly beiow this
level for CW. When driving a final amplifier
stage with the HT-32A Transmitter/Exciter,
advance the RF LEVEL control until required
excitation is obtained for the amplifier. In
either cage, do not operate beyond the satura-
tion level.
A convenient reference for this operating level
may be obtained by setting the METER COM-
PRESSION control so that the output meter
reads zero DB.
Recheck the driver and final tuningby reducing
the carrier level by about Sor 10 DB onthe out-
pnt meter withthe R F LEVEL control and touch-
ingup the DRIVER TUNE and FINAL TUNE con-
trols for maximum output. Reset the RF LEVEL
control for maximum output just below the satu-
ration point, as outlined above.
Open the key. The output should drop to zero,
When the transmitter and récéiver share the
same antenna (via an antenna relay), manual
CW operation is accompUshed by switchingbe-
tween "MOX" (to transmit) and "STANDBY"
(to receive), Note that manual operation will
not be possible unless the CW DELAY control
fkmurled sleeve shaft of R49) is turned fully
(onan ee ee elit
clockwise. See Figure 9,
Antomatic break-in keying with a shared an-
tenna system is accomplished by placing the
OPERATION contrul in the "MOX" position,
and turning the CW DELAY control (sleeve
shaft) counterclockwise untilthe VOX relay
de-energizes (as in "receive" operation), With
this accomplished, any time the key is closed,
the VOX relay will energize, and immediate
transmission will begin, startiug from the first
dot. Note that this setting of the CW DELAY
control (sleeve shaft) affords the longest delay
between the time transmission ends and the
receiver is reactivated. For shorter delays,
turnthe CW DELAY control (sleeve shaft) fur-
ther counterclockwise, Torestore normal CW
operation on "MOX", return the CW DELAY
control {sieeve shaft) to its maximuin clock-
wise position,
Note that the CW DELAY (sleeve shaft) control
adjustment need not be changed when switching
to other manually operated modes of operation,
such as DSB or SSB; but, if normal mannal CW
operation is desired, the CW DELAY contrul
(sleeve shaft) must be set at its maximum clock-
wise position,
Refer to the use of the "CAL" position of the
OPERATION switch andthe CALIBRATE LEV-
EL control for "Zeroing-in" on the receiver
frequency. See paragraph 3-11,
4-5. SSB TUNING.
OPERATION switchat MOX; FUNCTION
at DSB (Audio level zero).
2. Tune the driver aud final amplifier stages as
described for CW tune up.
w
. Set the FUNCTION switch to UPPER or LOW-
ER sideband as desired. If the outpnt meter
was referenced at zero DB for maximum out-
put with the COMPRESSION control, the meter
will now indicate the carrier suppression di-
rectly in DB below maximum output.
4, Set the OPERATION switch at MOX (manual
operation).
5, While monitoring the transmitter output, pro-
ceed with SSB transmission, setting the AUDIO
LEVEL control for the required audio gain
which dees not produce peak flattening or over-
joad distortion of the outpnt signal Note that
the output meter damping factor prevents the
meter from indicating ODB reference on voice
«sade The moter will awing raughly 9/3 aeal a
pean, 2A GEAR Week ee i de 2 ee yf eee
with voice excitation,
6. If manual operation is desired on SSB, switch
the OPERATION control between MOX and
STANDBY. For voice control operation, with
the receiver and transmitter interconnected,
set the OPERATION control at PTT-VOX. To
"zero-in" on frequency, see paragraph 3-11 re-
garding the calibration procedure. For infor-
mation on the use of the VOX, DELAY, and
ANTI-TRIP controls, see paragraphs 4-8 and
4-9.
4-6. AM (DSB) TUNING.
The tuning procedurefor AMoperation is asfollows:
1, Set the OPERATION switchat MOX; FUNCTION
switch at DSB (Andio level zero),
2 Tune the driver and fiual amplifier stages as
described for CW tune up.
3. Whenfeeding a dummy or antenna ioad, advance
she DOT ay
the RF LEVEL control to the saturated output
level and reference 0 DB on the output meter
withthe METER COMPRESSION control, as de-
scribedfor CW tune up, When driving alinear
power amplifier withthe HT-32A Transmitter /
Exciter, advance the RF LEVEL control until
maximum linear power ontput is obtained from
the finalamplifier stage before setting the ref-
erence level on the output meter,
4, Withthe RF LEVEL control, reduce the carrier
level 6 DB, as read on the outpnt meter, This
sets the maximum carrier levelthat the linear
amplifiers inthe HT-32A Transmitter /Exciter,
or following linear power amplifier, can handle
and provide 100% modulation capabilities, This

carrier reference level can be established
more precisely if an oscilloscope and audio
oscillator are used to set up and monitor the
output signal Note that if the carrier level is
set too high, peak amplitudesare flattened be-
fore 100% modulation occurs. If the carrier
level is set too iow, the maximum power output
capabilities are not attained at 100% modulation,
Whila monitoring the tranemittear output, pro-
Ts oom
ceed with AM transmission, setting the AUDIO
LEVEL contro! for the required audio gain
which does not produce peak flattening, or over
modulation distortion of the output signal Note
that the output meter damping factor permits a
Tough operational check on over-modulation.
The output meter will drop about 1 to 2 DB in
level when the percentage of modulation with
voice excitation runs close to 100%,
nm
§&. If manual uperation is desired on AM, switch
the OPERATION control between MOX and
STANDBY. For voice control operation with
the receiver and transmitter interconnected,
set the OPERATION control at PTT- VOX,
4-7. SEGMENT ALIGNMENT FOR 10M BAND.
ar
The HT-32A Transmitter /Exciter is set up at ihe
factory to provide transmission in the 28. 5 to 29, 0 MC
segment of the 10M band.
The other 0.5 MC segments of the 10M band are
set up as follows: (Refer to » Figure 6 i or ijocations of
+ha
tha yarieus adjustme entea following
wa = wa A wee
procedure, )
1. Tune up on CW and determine the saturation
level settings of the RF LEVEL control. Re-
cord this settingfor future reference in step 5.
Remove the 32.5 MC crystal and insert de-
sired crystal *
019-201963
019-201964
01 9-201965
019-201966
supplied with the transmitter,
3 Connect electronic voltmeter or similar high
impedance DC voltmeter (0-10¥V) to crystal
oscillator test point, and adjust crystal os-
eillator trimmer for approximately half of the
yoltags obtained at the maximum voltage setting
of the trimmer. Set the trimmer on the gentle
Slope side of resonance,
4. Set TRAP TRIMMER for minimum capacity and
adjust 10M mixer trimmer for maximum out-
put. Increase RF LEVEL contral setting, if
necessary, to pick up an output meter reading
as the mixer ig tuned to resonance, Back off
the RF LEVEL as resonance is obtained with
mixer trimmer and DRIVER TUNE control
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TEST
TRAP
Figure 6. 10 Meter Band Adjustments
Touch
al ?
up FINAL TUNE control, then adjust
crystal oscillator trimmer and RF LEVEL con-
trol until the saturation output again occurs at
the RF LEVEL setting, originally obtained for
the previous crystal used, See step 1,
§. Trap adjustment - This adjustment is optional
as far as spurious output inthe 10M band is
concerned, since its level is less than 60 DBhbe-
iow fundamental only when the transmitter is
mistuned. To locate the spurious signal, turn
the RF LEVELecontrol to zeroor switch to the
upper or lower sideband position of the opera-
tion switch, and tune the DRIVER TUNE and
FINAL TUNE for maximum output. Adjust the
10M trap trimmer for minimum output meter
reading.
7. Re-check the 10M mixer trimmer setting by
retuning for the desired frequency and peak-
ing the trimmer, since the trap adjustment
will affect the original mixer setting slightly.
4-8. USE OF VOX AND DELAY CONTROLS.
The
VOXand
DELAY
controla
are
locatedon
the
top
of the HT-32A Transmitter /Exciter chassis, as illus
trated in Figure 7. Both controls are utilized in con-
junction with VOX operation and are adjusted to pro-
vide control of the transmitter and station receiver.
1. The VOX contro] is an audin sensitivity con-
trol which determines the andio level that
will trip (energize) the VOX RELAY, and place
the HT-32A Transmitter /Exciter "on the air",
This control should be adjusted with the micro-

aeete
oes
SIDE BAND
SENERATOR
CHASSIS
cue
TI
T2
Figure 7.
phone at the normal speaking distance from the
month, Advance the VOX control to a setting
slichtly above that which will "trip" the VOX
ee ea pee ere)
RELAY, Excessive sensitivity will have the
undesirable result of background noise “trip-
ping’ the VOX RELAY and placing the HT-32A4
Transmitter /Exciter on the air. Note that the
VOX sensitivity control and the AUDIO LEVEL
control for the microphone are separate level
adjustments; hence for example, backing off
the AUDIO LEVEL control will not reduce the
VOX sensitivity.
The VOX DELAY control (center shaft) is in the
grid circuit of the relay tube and determines the
time lag inde-energizing the VOX RELAY when
audio excitationis removed from the audio am-
plifier and VOXamplifier stages. This control
should beadvanced while speaking into the mi-
crophone and set at a position in which the time
lapse between words will not de-energize the
VOX RELAY, This adjustment will eliminate
the constant keying ofthe HT-32A Transmitter /
Exciter at the beginning of each word when
speaking, There is a slight interaction be-
tween the VOX and DELAY circuits, conse-
quently, a slight re-adjustment of both con-
trata maw hoe neaeaceare ty ahtain dooinad wra_
Me Uas Lia OC BCCCOba! Lu Otel Goolred be
sults, The VOX DELAY edjustment (R494) is
the center shaft with the screwdriver slot. See
Figure 9, For adjustment instructions con-
cerning the sleeve shaft (CW DELAY), see
paragraph 4-4, step 9.
4-9. USE OF ANTI-TRIP CONTROL.
This control is lLocatedon top of the HT-32ATrans-
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Top Chassis View
mitter /Exciter chassis (Figure 7) and is used in con-
junction with VOX operation, When the station receiver
and speaker are connected for VOX operation (para-
graph 2-5-2-4), the speaker ANTI-TRIP control is ad-
vanced to a setting where the audio signal picked up by
the microphone from the receiver's speaker will not
energize the VOX RELAY, This feature prevents the
re-transmitting of the incoming audio signals from
your station receiver. Note that an excessive speaker
gain Setting is capableof disabling the VOX relay com-
pletely, hence the minimum required gain should be
used for best resuits.
4-10. BIAS ADJ. CONTROL.
This control has been factory set for -49V as meas-
ured at the adjacent TEST terminal with the transmitter
operating from a 117V line.
The controlis located to the rear of the chassis and
Slightly to the right of center. (See Figure 7).
An occasional check with an accurate, high resis-
tance voltmeter will insure maximum tube life since
the 6146 final amplifier tuhes are operated close to
rated plate dissipation for optimum performance. Do
not use a voltmeter with less than 20, 000 ohm per volt
pide
To adjust the bias, set the OPERATION switch at
MOX, FUNCTION switch at either sideband (zero sig-
nal) and adjust for -49V+41V with the voltmeter con-
nected between the test point terminal (-) and chassis
(+). Note polarity since this is a bias voltage
Se DN ky a Viet Se
Note that the bias voltage specified is for operation
from a 117¥V line and that it will rise and fall with the

Source voltage. In cases where the power source volt-
age cannot be set at 117V te make the bias adjustment,
make allowances for it when setting the bias. For
if the line voltage al wan T1S9tr set the
example, orege measures licy,
bias at -47V; ifat 115V, set at -48V; if at 120V, set
at -50V; and if at L22V, set at -51V.
Setting the bias abnormally high or low because of
meter errors etc., will not only affect the final tubes
but the over-all transmitter performance as weil,
Since the bias level also controls the over-all trans-
mitter sensitivity.
4-11. MODEL HT-32A TRANSMITTER/ EXCITER
WITH LINEAR POWER AMPLIFIER.
When the Model HT-32A Transmitter/Exciter ig
used todrive a linear amplifier, swamping or padding
between the units may be required for optimum perfor-
mance.
The degree of swamping or padding will depend upon
the driving power required by the linear amplifier.
High powered grounded grid or triode amplifiers gen-
erally will require little or no swamping since the
driving power will be essentially equal to the power
output capabilities of the HT -32A Transmitter /Exciter.
Linear power amplifiers using tetrodes or pentodes on
the other hand generally require considerably less than
the peak power output available from the HT-32A
Transmitter/Exciter.
In general the swamping bet ween units should "soak"
up the unused driving power so that the driver unit
(AT-32A) is running reasonably close to its peak power
output andterminatedin a 50-ohmload. This condition
will retain the carrier Suppression of the HT-32A
Transmitter/Exciter for the overallsystem as well as
hum and noise ratio which are all related to the peak
envelope power output.
FSR
JACK
For example - Should the linear power amplifier re-
quire 40 to 50 watts of drive, thena 3DB T pad designed
for 50-ohm terminations would fully load the HT-32A
Transmitter/Exciter while still transferring the re-
quired driving power to the final amplifier grids.
4-12, SERVICE OR OPERATING QUESTIONS.
For further information regarding operation or
servicing of your Model HT-39A Transmittar /Exciter,
write to:
General Service Manager
The Hallicrafters Co.
4401 West Fifth Avenue
Chicage 24, Dlinois
Be sure to include the model, serial, mark num-
ber, and date purchased.
Make no service shipments to the factory unless in-
structed to do so by letter. The Hallicrafters Com-
pany will not accept the responsibility for unauthorized
shipments.
The Hallicrafters Company reserves the privilege
of making revisions in current production of equip-
ment and assumes no obligation to incorporate these
revisions in earlier models.
2 ttt ondped
Figure 8. Bottom Chassis
-12-

SECTION V
BASIC OPERATING THEORY °
5-1.
BASIC
OPERATING
opine
ns
HET
OPERATION.
The basic operating principles of the Model HT-32A
Transmifter/Exciter is explained in thefollowing sub-
paragraphs. Figure 11 is a block diagram of the HT-
32A Transmitter /Exciter and figure 14 is the schematic
diagram. The complete system is first discussed for
SSB operation and a brief description of CW and AM
operation follows.
PTION.
Tube VlAisa4, 95 MC crystal controlled oscillator;
Its output frequency is ultimately converted to the de-
sired operating frequency by heterodyne action in the
succeeding stages. The output of VIA is a 4,95 MC
signal which is fed directly to the tank circuit of the
bridged-T modulator network, The audio input is im-
pressed across diode modulator V14 which is part of
the grounding leg of the bridged-T modulator network,
The proper phase relation has been obtained by the
CARRIER BALANCE controls,
In SSB operation, (FUNCTION switchin UPPER SB
or LOWER 5B position), thebridged-T modulator net-
work ls placedina balanced condition and carrier out-
put is at least 50 db below peak envelope power. Under
balanced conditions, the outputof thebridged-T modu-
later network consists of theupper and lower sideband
of 4.95 mc. A filter system, in the input and output
circuits of the sideband filter amplifier stage, V2,
suppresses the lower sideband of the modulated 4, 95
mc sigual. The upper sidebandis fed tothe let mixer,
v3, where it is combined with 4.05 mc or 13. 95 mc,
as selected, from V4, The oscillator frequency used
determines whether the upper or lower sideband is
transmitted, For example:
1, Tone sideband - the upper sideband of 4. 95
mo ig mived feum) with 4,05 me te obtain
ae a Aka eee
the upper sideband at 9me. The inter-stage
coupling between Ist mixer, V3, 9 mc ampli-
fier, V5; and 2nd mixer, V7 consists of tuned
transformers T1 and T2 which pass ouly a band
of frequencies near 9 mc.
2. Lower sideband - the upper sideband of 4. 95
is mixed with 13.95 mc to obtain the lower
sideband at 9 mc. As in the upper sideband
condition, the inter-stage coupling of V3, V5,
and V7 pass only the frequencies near 9 mc.
\
Upto the input stage of 2nd mixer, V7, the operation
of the HT-32A Transmitter/Exciter is identicalon all
bands. The remaining stages "beat" (sum or differ-
erence) the selected 9 mc sideband to thedesired oper-
ating frequency. Frequency multiplication cannot be
used since doubling the frequency would double the
spacing of the sidebands. This would change the rela-
tive frequency of the modulating frequencies when the
signal is detected.
-}3-
The selected sideband (upper or lower) at 9 mc is
amplified by 9 mc amplifier, V5, and fed to the 2nd
mixer V7, On 80 meters, heterodyne oscillator, V6,
has no output and the 2nd mixer, V7, functions as an
additional amplifier, At the 3rd mixer, V8, the side-
band is mixed (difference) with the output frequency of
the VFO, V9. Since the VFO output frequency is tuna-
ble from 5.0 to 5. 5 mc, the difference output of V8 is
the sideband of a frequency between 3, 500 te 4. 000 mec.
5-4, 40 METER OPERATION.
The selected sideband at 9 mc is mixed (difference)
with a 21. 5 me output of heterodyne oscillator V6 in
2nd mixer, V7. The output of V7 is a sidéband at12. 5
me which is applied to the 3rd mixer, V8. In this stage,
the sigual is mixed (difference) with the VFO output
(5. 0 to 5, 5 me); the resulting sigual is the sideband of
a frequency between 7. 000 to 7. 500 me,
5-5. 20 METER OPERATION.
Operation on 20 meters is essentially the same as
80 meters except that "sum" mixing ls empioyed in
place of "difference" mixing at 3rd mixer, V8. When
the VFO cutput (5. 0 to 5. 5 mc) is mixed with theupper
or lower sideband at 9 me, the resulting sigual is the
Boe meets a a a
sideband of a fr equency between 14, 900 mcto 14, 5 mc,
5-6. 15 METER OPERATION.
The selected sideband (upper or lower) at 9 me is
mixed (difference) at 2nd mixer, V7, with a 25 mc sig-
tite
nal fr om heter odyne oscillator VE; ¢ the output of Va is
a sideband of a1I6 mc signal. This sigual is applied
to 3rd mixer, V8, where it is mixed (sum) with the 5. 0
me to 5, 5 meoutput of the VFO, V9. The result of the
mixing action is a sideband of a frequency from 21. 0
me to 41, 5 me.
Four disttnet ranges are provided for complete
coverage of the 10 meter band. Each range utilises a
separate frequency fromthe heterodyne oscillator, V6.
The operation in the four ranges 1s as follows:
1. 28 mc to 28.5 me. - The selected sideband at
9 mc is mixed (difference) at 2nd mixer, V7,
with 232. Ome sigual from heterodyne oscillator
v6. The resulting signal, a sideband at 23. 0
me is applied to 3rd mixer, V8. In this stage,
the sideband at 23, 0 mcis mixed (sum) with the
VFO output (5,0 me to 5.5 me). The resuiting
signal is a sideband at a frequency between
28, 0 mc to 28, 5 me.
2. 28.5 mc to 29 me. - For this range, the 9 me
Sidebandis mixed (@ifference) with the 32, 5 me
signal from heterodyne oscillator V6, in 2nd
mixer V7. Theresulting signal, a sideband at
23. 5 mc, is mixed (sum) in the 3rd mixer, V8,

with the 5.0 mc to 5. 5 me output of the VFO.
The output of V8 is a sideband at a frequency
between 28. 5 me to 29 mec.
29mc to 29, 5 me - As inthe abovetwor anes >
the selected sideband of the 9 me sigual from
V5 is applied to 2nd mixer, V7. Here it is
mixed (differ ence) with the 33 mc output of V6.
The output of V7 is a sidehand at 24 mc. This
signal is mixed (sum) in 3rd mixer, V8, with
the VFO output, The resulting signal is a ge-
lected sideband at a frequency hetween 29 mc
to 29. 5 mc.
oo
29. 5mcto30mec. - Foroperation in this range,
the heterodyne oscillator, V6, injects 233. 5mec
Signal in V7 and is mixed (difference) with the
selected sideband at 9mc. The resulting fre-
quency, a sideband at 24. 5 me is mixed (sum)
in V8 with the 5.0 me to 5.5 me output of the
6-1. TECHNICAL SPECIFICATIONS.
17 pilus 1 voltage regulator and
2 voltage rectifiers
105-125 volts, 50/60 cycles AC
POWER SOURCE,,.
ear Aes
POWER OUTPUT:
ae (PEB) 2... ccc cece eters 70-100 watts
eee ete e nett e eta ea wees 70-100 watts
AM (CARRIER)... 0... ccc ceeeenenee 17- 25 watts
AUDIO INPUT...........06. 0, 004V rms minimum
STABILITY 2... cece ee neces ..+. 0.009% maximum
HUM AND NOISE OUTPUT ...... Atleast 40 db below
carrjer
UNWANTED BEAT OUTPUT .... At least 55 db below
carrier
FREQUENCY COVERAGE 80, 40, 20, 15, and
10 meter bands
FREQUENCY SELECTION....... Self contained VFO
DIMENSIONS. ...-....00e ce eanaeeues 10-3/8" Height,
16" Deep, 20" Wide
85-1 /4 lbs,
es
6-2. CHASSIS REMOVAL.
The chassis and front panel assembly are removable
as aunit from the cabinet by removing 2 screws at
each side of the front panel and the 3 screws on the
underside of the cabinet.
6-3. TUBE AND DIAL LAMP REPLACEMENT.
Access to the dial lamps and all tubes may be cb-
tained by raising the top cover of the cabinet.
ee a
SERVIVING [RE Ni-v 4a
TRANSMITTER/EXCITER
Throughont the design of the Model HT-32A Trans-
-14-
VFO, The output of V8 is a sideband at a fre-
quency between 29. 5 me to 30 mc.
When the FUNCTION control is set to CW or DSB
position it unbalances the "bridged-T" modulator net-
work, allowing a carrier to be amplified and hetero-
dyned to the desired output frequency. Two sections
of the FUNCTION switch bypasses the 4, 95 mc filter
(V2 and associated circuitry) in the CW" or "neRtt
position. With these exceptions, CW operaticn is the
same a8 SSB operation,
5-9, DSB (AM) OPERATION.
As in CW operation, the carrier frequency is pre-
sent in the sigual and the 4, 95 me filter is bypassed,
Amplitude modulation of the carrier occurs across
diode medulator V14. The resulting signal is ampli-
fied and heterodyned as in CW and S5B operation.
mitter/Exciter, full consideration was given to keep
maintenance problems at an absoluteminimum, In all
well designed communications equipments, mainte-
nance and repair problems are generally confined to
the checking and replacement of tubes which may be-
come defective. Malfunctions of this nature are easily
isclated and corrected, However, it is entirely pos-
sible that a more ohscure malfunction may arise, In
this event, ouly thoroughly trained technical personnel
should attempt servicing the unit.
Arecommended aidfor troubleshooting the HT-32A
Transmitter/Exciter is a general coverage receiver.
This receiver can be uSed to provide a quick check on
various oscillator circuits inthe HT-32A, Alead con-
nected to the antenna of this general coverage receiver
when placed in the proximity of the oacillater tube in
the circuit to be checked can determine the presence
or absence of sigual from the stage in question.
NOTE
The frequencies cf the various crystals can vary
somewhat from the frequencies marked thereon,
The frequencies of all the mixer stages can
also vary to some degree,
if a malfunction oecurs when operating on one par-
ticular band and mode of operation, the unit should be
checked on all other bands and in all other modes of
Operation to Isolate the difficulty. A careful study of
the block diagram (See Figure 11) should give a quick
clue as te which tubes should be checked. The sche-
matic diagram (Figure 14) voitage chart (Figure 12)
and resistance chart (Figure 13) and the following table
will prove to be a valuable aid in isolating and cor-
recting a malfunction,

TROUBLE SHOOTING CHART
Possible Cause
No outpnt any band SSB only
No output
Ne output
No outpni
No outpnt
Ne output
80 Mirs.
40 Mtrs.
USB
LSB
All Medes
Check V2.
Check v4
Check V4
Check v4
Check v6
Check V4
Check V4
Check V4
Check V4
Check v4
Check v4
13.95 MC
13.95 MC
4.05 MC
13.95 MC
13,95 Mc
Check V6
Check Xtal frequency of
portion in use.
a Se oe a |
whl VE
Check v4
Check V4
Check V15, V16, V17
Check for Hum V13, V15, V17
Check V15, V16, V17
SECTION VII
HT-32A ALIGNMENT PROCEDURES
(Figures 9 and 10 Cover These Procedures)
7-1. EQUIPMENT REQUIRED.
1.
RF Signal Generator - Measurements Corp.
Model 655 or equivalent having a 1V RMS out-
put at an impedance of 70 OHMS or less, (A
100 mmf DC blecking capacitor must he placed
in series with the RF lead. )
2. Vacuum tube voltmeter (VI'VM) - Hewlett Pack-
ard 410A or equivalent having an RF probe good
to 35 MC.
3. Dummy load - 50 ohms non-inductive, rated ai
100 watts. The dummy loadmay be made up of
carbon resistors, Bird Wattmeter, or equiva-
lent.
4, DC Milliammeter 0 - 300 MA DC,
5. DC Voltmeter with 20,000 chm per volt sen-
sitivity.
6. Receiver (3-30 MC range) with 50 KC calibra-
tor. (Essential adjustments can be done with
100 KC ealibrator. )
%. Audio Frequency Signal Generator covering
range of 100 CPS to 5000 CPS,
8 Ballantine voltmeter or equal capable of read-
ing 2 to 4 millivolt level.
7-2. INITIAL CONTROL SETTINGS.
OPERATION STANDBY (Power on}
FUNCTION DBS
CALIBRATE LEVEL 0
DRIVER TUNING Fully counterclockwise (Closed
gang)
FINAL TUNING ON INDEX (Closed gang)
FREQUENCY Fully counterclockwise (Closed
BAND SELECTOR As instructed
AUDIO LEVEL 0
METER COMPRESSION 10
RF LEVEL . o
7-3. BIAS ADJUSTMENT.
Check the bias voltage before running any extensive
checks with the plate and screen voliage applied to the
6146 final ampHfler tubes. Set BIAS ADJ. for -49V
-5-

DC +1V with the OPERATION switch at MOX, , FUNC-
TION switch at either npper or lower sideband (ere
signal). Line voltage 117V. See paragraph 4-10 for
additional comments on bias adjnstments.
7-4, RF ALIGNMENT 2ND AND 3RD MIXER
AND DRIVER STAGES.
IMPORTANT: The RFalignment should only be
attempted when an H]-32A Transmitter /Exciter
maifunction has been analyzed and definitely
traced to RF misalignment.
Remove 21.5, 25, and32.5 MC Xtals;Ogc. Tube V9;
HV Rect V18; and 9 MC RF cable from SB generator.
7-4-1. 3RD MIXER AND DRIVER STAGES.
Disconnect screen lead of V11 (6146, Final Amp)
from ing at terminal board on underside of chassis.
Set neutralization capacitor C44 and VFO conpling
capacitor C1l5atmid-capacity, if these components are
new and have never been adjusted before.
To place the transmitter in operation for alignment,
set OPERATION control at MOX. This places operating
bias on the 2nd and 3rd mixer stages.
We
“ “©
cree al
RSS ror! Piél SMC INPUT Cill T2
PMASE a TO MAIN CHASSIS
Tor OF CAN
Figure 9.
OANGER HIGH VOLTAGE
THERE ORE NO SLIGNMENT
ADJUSTMENTS UNDER
THIS SHIELD
JO |
i
Zan?
(vs) ant) TRIP
VOX DELAY —CENTER
R49 4 cw DEL AY—SLEEVE
JECTION
GRID OF VBIS CONSTANT
ACROSS WFO DIAL(30-S3mC}
c202
TEMPERATURE COMPENSAT IS
ADJUSTMENT IS FACTORY
ADS TENT
Céé
Lad cé4
Oog-z0s088¢
Top Chassis Alignment Points
-]6-

7-4-1, 3RD MIXER AND DRIVER STAGES (CONT.).
ALIGNMENT CHART
Signal
Generator VIVM
Step! Band Connection Connection
Trimmer Coil Signal Approx,
Adjust Adjust Generator Driver
for for Freg. Tuning
Maximum | Maximum MC Setting
I 80M | High Side to Pin #1 grid of V4 | VI'VM to Pin #5
(G6AH6, 3rd Mixer) Common | gridof VIL (6146
side to chassis. (Generator |Final Amp. )
leads must be kept to abse- |Common ta
lute minimum to prevent re- | chassis.
generation. )
2 40M | Same as step 1. Same as step 1,
3 20M |Same as step 1. Same as step 1.
4 15M |Same as step 1. Same as step 1.
5 10M |Same as step 1. Same as step I.
7-4-2. ALIGNMENT PROCEDURE.
1. The 3rd mixer and driver stages aligament pro~
cedure for 80, 40, 20 and 10 meter bands, is
essentially the same, differences beingonly in |
frequency used and adjustment Iccation which
can be obtained from the chartabove. The fol-
lowing iS the alignment procedure for 80 me-
ters, Preset the Initial Control Settings with
the BAND SELECTOR set on the band being
aligned (80M).
(a) Set trimmers (C26 and C43) to mid-capacity.
(b) Preset slugs (L7 and L11) to their maxi-
mum inductance if they have never been
previously aligned.
—
(c) Set the DRIVER TUNING to D, (1.3 on
Knob),
—
(a) Set theR, F. Generator tof, (3.5 MC) using
sufficient generator output to obtain a read-
able indication on the VIVM. If 1V out of
the signal generator does not provide a
VIVM reading proceed with slug adjuet-
ment below.
(fe
—
Carefully adjust each slug (L7 and L11)for
maximum deflectionon VIVM. Userefer-
ence voltage on VI'VM of approximately
20V RMB,
¢) Adjust the output frequency of the R. F.
generator tof, (4.0 MC) using sufficient
generator cuiput te cbtain about 20V RMS
at the grid.
(g) Tune DRIVER TUNING for maximnm de-
-|7-
C26 L7 3,5 4.0/1.3} 3.7
C43 Lil
C25 L6
C42 L190 7.0 7.3 (09/41
C22 LS 14.0 |14.35/L113.7
C38 Lg
21, 0
flection on VIVM. Driver tuning setting
should be approximately Do (3.7 on the
Knob).
th) Adjust trimmers (C26 and C43) for maxi-
mum defiection on VIVM.
fi) Repeat steps (¢) thru (h) until the adjuet-
ments result in noappreciable increase in
grid voltage. The band is then correctly
tracking with maximum output.
The 3rd Mixer and Driver Alignment procedure
for 15M is slightly different, since the 20Mand
15M bands share the same coil. The following
is the alignment procedure for 15 meters.
(a) Align 20 meter band as outlined ahove.
(b) Set BAND SELECTOR at 15M.
(c) SettheR. F.generator atf, (21. OMC) using
Sufficient generator output to obtain about
2Z0V RMS at the grid of the final amplifier.
(@) Tune DRIVER TUNING for maximum de-
flection of VIT'VM. Driver tuning setting
should be approximately Dz (1, 8 on the
knob). ,
(a) Adjust slugs (L5 and L9) for maximum de-
flection of VIVM. if additinnal. gain is
obtained with this adjuetment, repeat 20
meter trimmer alignment at 14.35 MC and
check 14.0 MC for uniform gain on 20M
has
band
ff) Repeat above procedure until no further
gain can be obtained on both bands.

7-4-3.
2ND
MIXER
STAGE.
ALIGNMENT
CHART
Trimmer) Slug Sigual
Signal
Adjust
|
Adjust
Generator
VFO
Generator
VIVM
for
for
Freq.
Freq.
Connection
Connection
Maximum
|Maximum
(MC)
(MC)
Step | Band
High
side
to
pin
#1
grid
of
V7
VIVMto
pin
#5
grid
(6AH6,
2nd
Mixer).
Common
|
of
Vil
(6146,
Final
side
to
chassis.
Amp.
).
Commonto
chassis.
Same
as
step
1.
Same
as
step
I.
Same
as
step
i.
Same
as
step
I.
BREAK INTO HY B+
FED WIREIGIRGUIT HERE
TO METER PLATE
CURRENT FOR NEUTRAL IZING
AQUUSTME NT
DISCOMMECT SCRIEM
VOLTAGE SUPPLT LEAD
WHEN OPERATING #T- 52
WITH SR4GY HY AECT
Tu AF MOT
CMe
T3
TOA af. AST ET
WF OVECTION VOLTAGE at
GRID OF VaiS CONSTAUT
SCROSS VFO Gat.
OO hor
OR2-2038078
Figure 10. Bottom Chassis Alignment Points
|
-18-
[ae edema sie di Aes!

7-4-4.
ALIGNMENT
PROCEDURE.
8.
Adjust
mixer
coil
slug
L23
for
maximum
de-
flection
on
VT'VM.
The
2nd
mixer
alignmentprecedure
must
follow
the
sequences
shown
in
the
chart,
since
the
setting
of
the
9
Proceed
with
the
alignment
of
the
2nd
mixer
coil
inductance
on
40M
must
precede
the
trimmer
ad-
stage
on
15M
and
10M
using
the
chart
and
the
justments
on
15M
and
10M
bands.
The
following
is
above
procedures
used
on
40M.
the
alignment
procedure
fer
40
meters.
NOTE
1.
Set
BAND
SELECTOR
at
40M.
The
above
aligument
data
for
10M
2nd
mixer
adjustment
covers
the
28.
5-29,
0
MC
10M
seg-
2
Set
trimmers
C201
and
C78
at
mid-capacity.
ment
(82,
5MC
Xtal)
supplied
with
the
HT-324
Transmitter
/Exciter.
For
alignment
instruc-
3.
Set
slug
(L23)
at
it's
maximum
counterclock-
tions
covering
the
use
of
cther
10M
0.5
MC
wise
position
(minimum
inductance).
segments,
refer
ta
SEGMENT
ALIGNMENT
for 10M BAND in paragraph 4-7,
4, Set Sigual generator at f, (7.2 MC) with suf-
ficient
output
to
permit
setting
the
driver
The
2nd
mixer
plate
frequency
(fy)
for
the
various
tuning
to
resonance,
crystals
used
on
the
10M
band
are
a8
follows:
Trans. Freq.range | Xtal freq. | 2nd Mixer freq, (fo)
5.
Adjust
DRIVER
TUNING
for
maximum
de-
flection
on
VI'VM.
28.0-28.5MC
|
82.0McC
23.0
MC
6,
Set
VFO
dial
to
7.2
MC,
28.5
-
29.0
MC
32,5
MC
23.5
MC
7
SstR,
F.
generator
at
fo
(12.5
MC).
Set
gener-
29.0
-
29.5
MC
33.0
Mc
24.0
Mc
ator
output
for
approximately
20V
RMS
at
the
M
final
grid
while
making
aligument
adjustments.
29.5
-
30.0
MC
33.5
MC
24.5
MC
7-5.
HETERODYNE
XTAL
OSCILLATOR
ALIGNMENT.
ALIGNMENT CHART
Band
VIVM
Trimmer
Injection
Selector
Connection
Adjustment
Level
VTYM
to
pin
#1
of
V7
(GAH6,
0.
25V
RMS
2nd
Mixer),
Common
side
to
chassis,
2
40M
VTIVM
to
pin
#1
of
V7
(6AHG6,
Cé6
0.5
V
RMS
2nd
Mixer),
Common
side
to
chassis,
3
LOM
VT
YM
to
pin
#1
of
V7
(6AH6,
C64
0.5
V
RMS
ond
Mivar’
Common
side
te
MA APR fy
chassis,
7-5-1.
ALIGNMENT
PROCEDURE.
6.
Adjust
Xtal
Osc
trimmer
C64
for
0.5V
RMS
on
the
gentle
slope
side
of
resonance,
The heteredyne crystaloscillator aligument proce-
dure
mustfollow
the
sequence
shown
in
thechart,
since
7-6.
VFO
CALIBRATION
ALIGNMENT,
the
setting
of
the
coil
indnctance
on
15M
must
precede
the
trimmer
adjustments
on
40M
and
10M
bands,
Set
The
VFO
unit
has
heen
carefully
aligned
and
temper-
RF
LEVELat
0,
FUNCTION
switchat
DSB,
and
OPER-
ature
compensated
at
the
factory.
Before
touching
up
ATION
switch
at
MOX,
trimmer
C3
or
coil
Li,
check
the
dial
calibration
at
the
100KC
points.
H
ali
points
fall
to
one
side
of
the
1,
Set
BAND
SELECTOR
at
15M.
pointer,
resst
the
pointer
position,
If
the
calibration
"runs
out’
across
the
dial,
proceed
as
follows:
2
Adjust
Xtal
Osc
coil
slug
(L22)
for
0.
25V
RMS
on
the
gentle
slope
side
of
resonance.
1,
Set
OPERATION
control
at
STANDBY.
8.
Set
BAND
SELECTOR
at
40M.
2
Place
theantenna
lead
of
the
receiver
near
the
4,
Adjust
Xtal
Osctrimmer
C66
for
0,
5V
RMS
on
VFO
unit
and
set
the
receiver
at
5.0
MC
with
the
gentle
slope
side
of
resonance,
the
50
KC
calibrator.
Receiver
BFO
turned
off,
5.
Set
BAND
SELECTOR
at
10M.
3.
Tune
the
VFO
unit
to
4000
KCon
80M,
--

4, Adjust slug Li for zero-beat. 7, Adjust air trimmer C3 for zero beat.
5. Set the receiver to 5.5 MC withthe 50 KC cali- 8. Repeat steps 2, 3, 4, 5, 6, and 7 until cali-
brator at zero beat. bration is obtained at either end of the dial
scale,
6. Tune the VFO unit to 3500 KCon 80M.
7-7. RF ALIGNMENT 9MC AMPLIFIER STAGES.
f = ] _ 4 | | I |
Signai Signal
Generator Generator VIVM
Control
Cennection
High Side to Pin #1
Grid of V3 (@AH6,
on er en
WiLACL Jo WU
tat
LSL
Frequency Connection
VIVM RF probe to pin #5
Plate of V7 (6AH6, 2nd
nn a oe ait to
WLLACT. J LULL SUE LY
Setting
BAND SELECTOR, 20M.
OPERATION, Standby.
RF LEVEL, 10 (All
other controls at initial
Remove OSC, tubes
Vi, V4, Peak upper
a ee es aa
WL IVWEeS LU Ao
chassis,
mon to chassis.
7-8. CARRIER OSC. AND SIDERBAND
SWITCHING OSC. ALIGNMENT.
The carrier oscillator and sideband switching oscil-
iators are provided with minor frequency correction
trimmers which permit setting each oscillator to exact
frequency. The object of the oscillator frequency ad-
justment in the sideband generator unit is te provide a
carrier signal frequency of exactiy 9000 KC This is
accomplished by heterodyning the carrier oscillator
frequency (4950KC) with either the 4050 KCor 13, 950
KC sideband switching oscillator to produce a 9000 KC
signal at the output of the sideband unit.
7-8-1. CARRIER OSCILLATOR,
Ordinarily the carrier oscillater will not require
adjustment inthe field. If the 9 MC signal is not on
frequency, adjust the sideband switching osciliators
only. In cases where the carrier oscillator frequency
must be set, proceed as follows:
1. Set the OPERATION switch at the MOX posi-
tion,
Set the FUNCTION switch at DSB.
Tune up the transmitter on 80M into a dummy
e
Set the two CARRIER BAL trimmers on the
sideband unit for maximum carrier level and
if necessary detune with the DRIVER TUNE
control to prevent over-driving the final.
Adjust the CARRIER FREQ. trimmer (C-111)
for maximum carrier level, again detuning
with the DRIVER TUNE control to prevent driy-
ing the final stage into a saturation outpnt.
Set the carrier level with the DRIVER TUNE
control for 50V RMS across the dummy load,
oruse the output meter on the transmitter tak-
ing care to avoid driving the final into the sat-
-20-
control setting. )
NOTE.
NOTE.
10.
NOTE.
iL
7-8-2.
justments of T1 and
T2 for maximum de-
flection of VT VM.
(iV RMS)
uration level. Set the output meter sensitivity
for zero DB
Decrease the carrier osciilator frequency by
turning the CARRIER FREQ, trimmer until the
carrier level drops 20DBte 30 DB
The carrier oscillator frequency may not fall
exactly on 4950 KC which is stated in the man-
ual] as the nominal frequency,
Rebalance for maximum carrier suppression
with the carrier balance trimmers, Retune
the driver stage and check the low frequency
audio response. Use a 50V RMS RF output
level at 1000 CPS audio reference frequency.
The low frequency response for -3 DB will fall
between 500 CPS and 650 CPS§,
The low frequency audio response is directly
governed by the CARRIER OSCILLATOR freq-
uency. The carrier frequency is set in this
manner to insure carrier suppression of 40 DB
or more after a 30 minute warm-up,
Check theaudio frequency response at the high
end of the range. The output level should fall
-3 DB at 3000 te 4000 CPS. If adjustment is
required, adjust the AM coil (L-102) for the
correct response.
A change in the AM coil adjustment will gener-
ally require an adjustment of trimmer C-146,
in order to repeak the carrier level output for
DSB or CW operstion.
After the carrier frequency has been set, it is
now necessary to adjust the sideband switching
oscillators for exactly 9000 KC from the side-
hand unit as described in par. 7-8-2.
SIDEBAND SWITCHING OSCILLATORS.
Set band switch st 80M,
Disconnect shielded cable from sideband unit
at main chassis connector,