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-