Hallicrafters SX-140 Training manual

OPERATING AND
SERVICE INSTRUCTIONS
COMMUNICATIONS RECEIVER
MODEL SX-140

"The Hallicrafter's Company warrants each new radio product manu-
factured by it to be free. from defective material and workmanship
and agrees to remedy any such defect
or to furnish a new part in ex-
change for any part of any unit of its manufacture which under nor-
mal installation, use and service discloses such defect, provided the
unit is delivered by the owner to our allthorized raclio dealer, whole-
saler, from whom purchased, or, authorized service center, illtact, for
examination, with all transportation charges prepaid within ninety
days from the date of sale to original purchaser and provided that
such examillation discloses in our judgment that it is thus defective.
This warranty does not extend to any
of our radio products which
have been subjected to misuse, neglect, accident, incorrect wiring not
our own, improper installation,
or to use in violation of instmctions
furnished by us, nor extended to units which have been repaired
or
altered outside of Ollr factory or authorized service center, nor to cases
where tile serial number thereof has been removed, defacedorchanged,
nor to accessories used therewith not of our own manufacture.
Any part of a unit al'l"oved for remedy or exchange hereunder will
be remedied
or exchanged by tile allthorized radio dealer or whole-
saler without charge to the owner.
This warranty
is in lieu of all other warranties expressed or implied
and no representative or I,erson is allthorized to aSSlime for liS allY
other liability in connection with the sale of our radio products:'

092- 010393
Figure 1. Hal/icrafters Model SX-140
SECTION I
GENERAL INFORMATION
The new Hallicrafters Mo del SX-140 is a
pr ec isi on built, hi g hl y sensitive, co mmuni ca ti o ns
r ec eiver pr o vidin g co ver ag e within the fr equen cy
r ang e of 3.5 me gacyc les to 54 me gacyc le s. For
ea se and fle x ibili ty of o perati on, a s in g le tunin g
co ntr ol is pr o vid ed which cov ers the eas y -to-
re ad slide-rule dial spe c ifi c all y ca libr a ted for the
80, 40 , 20, 15, 10 an d 6 me ter ba nds. Fi ve tube s
p
lu s two sili co n re c tifi e rs are empl oy ed in the
la test superheter odyne Circ uit and pr ov isi on is
made for the re c epti on of a mplitu de mo dul a ti on
(A M) , sin gle -sideband (S SB), and co ntinu ous wa ve
(CW) signa ls ov er the e ntire tunin g r an ge .
For
co ntr ol of sel ec ti v it y, a r ege ner a ti ve
int e rm e di a te-fre qu ency st ag e is e mpl oye d. This
co ntr ol of re g ener a ti on al so pr ovid es a boo st in
se nsiti v it y to brin g in w eak or d ist a nt st a ti o ns
that wo ul d o rdin a ril y be lo st in th e b ac kgr o und
nois e.
A c arri er le vel meter pr o vides an a id for
a
cc ur a te tunin g a nd a me a ns of determinin g the
r ela tive strength of re c ei v ed si gna ls.
The a li g nm e nt pr oc edure for th e r ec eiver
h as b ee n g reatl y simplifi ed with the use of a
b
uilt-in cr y st al osc ill ator c ir c uit to g en er ate th e
req uir ed signals for a li g nm e nt. A 1650-KC cr y s-
ta l (n ot supplied) , plu gge d int o th e cr ys tal ca libr a-
tor s
oc ket , will pe rmit th e IF tr a nsf o rm er s to be
a li g ned with th e us e of th e C ar ri er Level meter
as an o utput indi ca to r.
Othe r sp ec ial feat ur es inc lu de : auxi li ar y
• 1 •
switching, contr o llin g an a ntenna changeo ver re-
lay, turnin g on the transmitter, or sh o rtin g th e
speaker voice co il durin g tr a nsmittin g (with th e
FUNCTION co ntr ol set to STANDBY). The SELEC-
TI V ITY -BFO co ntr ol, with its as soc iated c ir c uitr y,
permits co ntinu o usl y v ari a ble sele c ti v it y on AM
re c epti on to th e po int wher e the BFO starts.
Be yon d this po int, the c ir c uitr y permits r ec epti on
of CW
and upper or lo wer SSB si g nals . The pitch
of a CW si g nal m ay be vari ed with this co ntr o l.
The cr y stal osc illat or ci r c uit utiliz es . a 3.5-MC
cr y st al whi ch p ermits th e o per ato r to se t the low
frequen cy end s of the 80, 40, 20, 15 and 10 meter
ban ds and 52.5 MC on the 6 meter ba nd.
NOTE
Careful a ttenti on sh o uld be dire c ted to
the INSTALLATION and OPERATION
instru c ti o ns. The y ha ve been pr ov ided
to insure satisf a ctory o per ati on fr om
this Ha lli c rafters pre ciSion built pr o-
du ct. The re ce iv er has an unusuall y
hi gh d eg ree of sensitivit y necessar y to
r
ece ive weak and distant st a tions.
Carele ss o per a ti on of ahi gh sensitivit y
r
ec ei ve r m ay r es ult in ex c essi ve no ise
or b ac kgr ound hiss. These undesir-
a ble eff ec ts ca n be held to a minimum
by care ful a djustment of the SELEC-
TIVITY , TUNING, AUDIO GAIN andRF
GAIN co ntr o ls as well as the proper
sel ec ti on and a rr ang ement of the an-
te nna.

SECTION II
TECHNICAL DATA
TECHNICAL SPECIFICATIONS
TUBES ......... 0 • , 0 ••••• 0 •••••• 0 0 0 Five, plus two Silicon Rectifiers
HEADPHONE OUTPUT . . . . . . . . . . . . . . . .. Low to medium impedance (see para. 3-6)
ANTENNA INPUT. . . . . . . . . . . . . . . . . . • .. Single wire or any 50-75 ohms, unbalanced
POWER CONSUMPTION .. . . • . . . . . . . . . •. 47 watts
AUDIO OUTPUT IMPEDANCE ............ 3.2 ohms
DIMENSIONS. . . . . . . . . . . . . . . . . . • . . . .. 13-3/8" wide, 8-1/4" deep, 7-3/16" high
NET WEIGHT ..•.................... 13.5 pounds
SHIPPING WEIGHT. . . . . . . . . . . . . . . . . . .. 14 pounds
RECEIVER FREQUENCY COVERAGE
BAND IN FREQUENCY INTERMEDIATE OSCILLATOR
METERS RANGE FREQUENCY FREQUENCY
RANGE
80
3.5-4.0 MC 1650 KC 5150-5650 KC
40 7;0-7.3 MC
1650 KC 8650-8950 KC
20 14.0-14.4 MC 1650 KC
15650-16050 KC
15
21.0-21.5 MC 1650 KC 11325-11575 KC
10 28.0-29.9 MC 1650 KC 14825-15775 KC
6
50.0-54.0 MC 1650 KC 24175-26175 KC
FCC BAND
LIMITS
3.5-4.0 MC
7.0-7.3 MC
14.0-14.35 MC
21.0-21.45 MC
28.0-29.7 MC
50.0-54.0 MC
On some bands the frequency range of the receiver has been extended above the actual FCC
band limits to include the reception of some of the special service frequencies.
The oscillator frequency on the 80, 40, and 20 meter bands is higher than the received sig-
nal by the IF frequency. On the 15 and 10 meter bands, the oscillator second harmonic is used
which is higher than the received signal by the IF frequency. On the 6 meter band,the oscillator
second harmonic is used which is lower than the received Signal by the IF frequency •
• 2·

SECTION III
INSTALLATION
3-1. UNPACKING
Mter unpacking the receiver, examine it
closely for damage which may have occurred in
transit. Should any sign of damage be apparent,
file a claim immediately with the carrier stating
the extent of damage. Carefully check all shipping
labels and tags for instructions before removing
or destroying them.
3-2. LOCATION
The receiver is equipped with rubber mount-
ing feet for table or shelf mounting. When locating
the receiver, avoid excessively warm locations
such as those near radiators and heating vents.
Allow at least one inch of clearance between the
back of the receiver and the wall for proper venti-
lation.
3-3. POWER SOURCE
The SX-140 Receiver is designed to operate
from a 105-125 volt, 60 cycle AC power source.
Power consumption is 47 watts.
NOTE
If in doubt about your power source,
contact your local power company prior
to inserting the power cord into an AC
power outlet. Connecting the receiver
to the wrong power source may cause
figure 2. Single Wire Antenna.
. J.
extensive damage to the unit and costly
repairs.
3-4. ANTENNAS
The RF input of the receiver is designed
for operation from either a single-wire antenna
(fig. 2), a half-wave doublet or other tuned antenna
with transmission line impedances from 50 to 75
ohms (fig.3 and 4.). Antenna connections are made
to a two-terminal strip at the rear of the receiver
marked A (antenna) and G (chassis ground).
The
single wire antenna (fig. 2) may be used
in an area where antenna space is limited. When
using this antenna, a ground lead from terminal
G to a water pipe or other earth ground will im-
prove reception.
For the best performance, however, a co-
axial-fed dipole, tuned to the center of the desired
band, is the recommended type of antenna to be
used (fig. 3). The impedance of this antenna is
approximately 75 ohms. When using this antenna,
the center conductor of the coax is connected to
terminal A and the outer conductor (braid shield)
is connected to terminal G.
For further information regarding antennas,
refer to the "A.R.R.L .. Antenna Book", pub-
lished by the American Radio Relay League, West
Hartford, Conn., U.S.A.
I 468.,j
4 LIFEET), FREOUENCYIMC) I
092-0092098
figure 3. Dipole Antenna Using Coaxial Lead-in.

468 1
r UFEETl· FREQUENCY IMC j
~ 50-750HM ~¥ 0 o~
TWIN LEAD
!NSULATOR [§fBi]
09Z-0092!OC
Figure 4. Dipole Antenna Using Twin Lead-in.
3-5. SPEAKER CONNECTION
The speaker terminal board is marked
SPKR and GND. Internally, the hot lead from the
output transformer is connected through the
PHONES jack (J1) to the SPKR terminal; the other
transformer lead is connected to chassis ground.
3-6. HEADPHONES
The headphone jack, marked PHONES, is
located on the front panel of the receiver (as seen
in figure 5) and is wired to automatically disable
the speaker when the headphones are plugged in.
The headphone output impedance is not critical,
and any commercial headphones may be used, in-
cluding crystal types, as no direct current flows
in
the headphone circuit. For maximum headphone
output, the
use of low-impedance magnetic phones
(50 to 1000 ohm) is recommended.
3-7. TYPICAL SYSTEM CONNECTION
A four terminal strip is provided at the
rear of the chassis to connect the Receiver into
a station control system (see figs. 6 and 7). With
the FUNCTION switch in the STANDBY position,
terminals 1 and 2 are shorted together as are
terminals 3 and 4, thus providing auxiliary switch-
ing functions. Figure 6 illustrates the receiver
controlling the antenna changeover relay and the
station transmitter (such as the HT-40). Figure
7 illustrates the Receiver controlling the station
speaker and available contacts for another auxi-
liary switching function.
SECTION IV
FUNCTION OF OPERATING CONTROLS
4-1. GENERAL
Each control of the receiver performs a
definite function which contributes to its reception
capabilities. Full appreciation of the receiver is
to be expected only after becoming familiar with
each of the controls and the effect each control
has on the performance of the receiver.
A brief description of each control is con-
tained in the following paragraphs (see figure 5).
4-2. FUNCTION CONTROL
The FUNCTION control, a four-position ro-
tary switch, is used to select the desired operating
condition of the receiver. Auxiliary switching
functions are also controlled by this switch, refer
to paragraph 3-7. Operating conditions for each
switch position are as follows:
1. In the OFF position, no power is applied.
2. In the STANDBY position,power is ap-
plied to the receiver; however, a high
negative bias is applied to the RF tube
(VIA) grid to prevent the reception of
signals.
.4 •
3. In the AMposition, amplitude modulated
signals may be received and the AVC
circuit is activated.
4. In the CW -SSB position, continuous
wave and single-sideband signals may
be received. The AVC is reduced for
CW and SSB reception. The carrier
level meter is disabled to prevent
damage by a strong signal.
4-3. BAND SELECTOR CONTROL
The BAND SELECTOR control is a six-posi-
tion rotary switch, permitting the receiver
to receive Signals on either the 80,40,20, 15, 10,
or 6 meter band.
4-4. CAL-OFF CONTROL
The CAL-OFF control is a DPDT slide
switch. In the CAL position, the 3.5-MC crystal
marker circuit is actuated and provides beat sig-
nals at 3.5, 7.0, 14.0, 21.0, 28.0, and 52.5 MC.
With
the switch in the OFF pOSition, the crystal
marker circuit is disabled and no beat notes
will be heard.

PO NT
T r- I ER ALIGNMEN MARK
\\
CARRIER LEVEL
MAIN TUNING
FREQUENCY IN MEGACYCLES 80 M FREQUENCY IN MEGACYCLES
::n
CQ
c:
...
tD
!.II
<.n
."
...
0
::J
II ,I, U I i ,310u1~, rt
3;5 3,,6
3l
3;8
3.9 4.0
40 M
(Q),I
II SIINITS DB OYER sa
7.0
7
il
7.2 7.3
10 M
14
iO
I~I
I
1~3
14.4
ANT TRIM
CAL RESET
15 M
• •
2~0
2~.1
2F
21.3
2~4
2~5
0 0
10 M
• • •
21
0
2~5
29
2~.5
29.9
RECEIVER
""
~ 5~O
51.0
65 P
53.0
5~0
the hallicrafters CD.
MODEL 5X-140
'"tI
Q FUNCTION
PHONES
BAND SELECTOR
CAL R.F. GAIN ANL SELECTIVITY
AUDIO GAIN
::J
tD
20
15
B. F. O.
, .. -55"0
@ ,,"0'·
0 0 ® 0
A.M. 0
..
II
STAND BY
OFF
OFF OFF
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092-0095598

S)(-140 RECEIVER
CONTACTS OF
FUNCTION SWITCH
~AM.CW-SSB
1-', --"';> STANDBY
,--,--.-...
I ~~ ~O ~~~H~ ~~ ~~ 0 0e ~G~ 0
!
EXTERNAL
POWER SOURCE
'\[7
I-IT- 40 TRANSMITTER
SWITCH CONT.e.CTS SHOWN IN NORMAL
OR RECEIVING POSITION
Figure 6.
Station Control, Receiver Controlling Antenna Relay and Transmitter.
sx - 140 RECEIVER
CONTACTS OF
FUNCTION SWITCH
AN, CW-SSB
AUXILIARY
SWITCH'''G
CONTACTS
SWITCH CONTACTS SHOWN
IN NORMAL
OR RECEIVING POSITION
HT - 40 TRANSMITTER
CONTACTS OF
FUNCTION SWITCH
~
STANDBY
ElCTERNAl.
Pa..'ER SOURCE
Figure 7.
Station Control, Transmitter Controlling Antenna Relay.
- 6 -
092-0096298

4-5. ANL-OFF CONTROL
The ANL-OFF control is a SPDT slide
switch. When the ANL-OFF switch is in the ANL
position, the noise reducing circuit is actuated to
improve reception of signals in the presence of
high
noise level, such as, ignition noise, atmos-
pheric static, etc. When placed in the OFF posi-
tion, the receiver resumes its normal reception
of signals.
4-6. RF GAIN CONTROL
The RF GAIN control is a variable resistor
in series with the cathode of the RF tube VlA. In
the
extreme counterclockwise position, maximum
resistance is introduced into the cathode circuit
thus developing maximum cathode bias to cut off
the
plate current. In the clockwise position, mini-
mum cathode bias is developed, plate current in-
creases,and RF gain is maximum.
4-7. AUDIO GAIN CONTROL
The AUDIO GAIN control, a variable resis-
tor, regulates the receiver volume. Clockwise
rotation increases the volume; counterclockwise
rotation decreases the volume.
4-8. SELECTIVITY-BFO CONTROL
The SELECTIVITY -BFO controls the ef-
fective resistance connected between the IF tube
(V3) suppressor and chassis ground. This control
varies the regeneration capabilities ofthe IF stage
up to and beyond the point of oscillation. During
the reception of AM signals, the selectivity ofthe
IF stage can be varied from approximately 8 KC
(control fully counterclockwise) to approximately
2 KC (control advanced to the point just below the
point of oscillation). For the reception of CW and
SSB signals, advance the control to the point of
oscillation or beyond. By varying the control
beyond the point of oscillation, the pitch of a CW
signal may be varied as desired.
4-9. MAIN TUNING CONTROL
The MAIN TUNING control is a variable
capacitor which determines the oscillator fre-
quency. It engages and moves the pointer on the
slide-rule dial when tuning in stations.
4-10. CAL RESET CONTROL
The CAL RESET control is a variable
capacitor connected in parallel with the MAIN
TUNING capacitor to permit recalibration of the
dial pointer on each band. This may be considered
as an electrical pointer reset. It is used primarily
in connection with the CAL-OFF switch when
setting the low frequency limits of each band and
the 52.5
MC point on the 6 meter band.
. 7.
4-11. ANT TRIM CONTROL
The ANT TRIM control is a variable capa-
citor which is connected across the secondary
of the antenna coils as each coil is switched into
the
circuit. It maintains perfect tracking of signals
on all frequencies of each band.
4-12. USE OF THE CARRIER LEVEL METER
The carrier level meter is useful onlywhen
the FUNCTION switch is set in the AM position
and permits the operator to obtain a relative
signal strength indication of the AM signals
received. When the FUNCTION switch is set to
the CW-SSB
position, the carrier level meter is
disabled to prevent the pointer from being abused.
In the AM position, the carrier level meter
is very sensitive and will permit an excellent
visual display of the relative strength of the in-
coming signals.
4-13. SERVICE OR OPERATIONS QUESTIONS
For any further information regarding
operation or servicing of the receiver, contact
The Hallicrafters dealer from which the receiver
was purchased. The Hallicrafters Company
maintains an extensive system of authorized
service centers where any required service will
be performed promptly and efficiently at a nominal
charge. All Hallicrafters Authorized Service
Centers display the sign shown below. For the
location of the one nearest you, consult the tele-
phone directory.
commu nlcotlonl
equipment
Do not make any service shipments to the
factory unless instructed to do so by letter. The
Hallicrafters Company will not accept the respon-
sibility for any unauthorized shipments.
The Hallicrafters Company reserves the
privilege of making revisions in current produc-
tion of equipment and assumes no obligation to
incorporate these revisions in earlier models .

SECTION V
RECEIVER OPERATION
5-1. STANDBY
Rot ate the FUNCTION contro l to the STAND-
BY po
sition . In this p os ition ,po wer is app li ed to
the re ce iver, as indi ca ted by illumination of the
t uning dial, thus allowing the r eceiver towarm up
prior to ca libr ation or normal ope ration (reception
of AM, CW or SSB si gna ls).
5-2. CALIBRATION
A specia l crystal oscillator circ uit (with
cr ysta l) has been inc or po r ated int o the re ce iver
to enab le the o perat or to accurately ca libr ate eac h
ba nd. A 3.5-MC cr y stal ins erted int o the crystal
socket (see fig. 8) pr ov id es a signa l that will zero-
beat wit h the l oca l osc illator to pr ov id e a ca li bra -
tion marker at the low frequen cy edge of the 80,
40, 20, 15 a nd 10 meter bands and at 52.5 MC on
t he 6 meter band . For ca libr ation of the re c ei ve r
pr eset the co ntr o ls as in di ca ted:
TI
CI
ANTENNA---
TRIM
C41
CAL
RESET
V2
6U8A
C42
ANT TRIM . . . . ... . .. C en ter of ran ge
FUNCTION ... .... ... CW -SSB
CAL-OFF . ... ....... CAL
ANL-OFF ..... ..... OFF
RF GAIN ... ... .. ... Maximum co unt er -
cl
oc kwise
AUDIO GAIN .... . . .. Maximum clockwise
BAND SE LECTOR . .... 80
MAIN TUNING ....... 3.5 MC
SELECTIVITY -BFO .... Maxim um cl oc kwise
The band edge ca libr atio n po ints for the 80,
40, 20 , 15 and 10 meter bands are 3.5, 7.0 , 14.0 ,
21.0, a nd 28.0 MC resp ective ly. These Signals ar e
V5
6AW8A
V4
~+----6T8
T3
MI LMI MAIN TUNING
V3
T2 6BA6
LM2
092-01 1 237
Figure 8. Top View Alignments .
· 8 ·