Hallicrafters SX-117 Training manual

OPERATING
AND
SERVICE
INSTRUCTIONS
FOR...
COMMUNICATION
RECEIVER
MODEL SX-117
the
hallicraftfers
COQz
A
Subsidiary
of
Northrop
Corporation

SECTION II
TECHNICAL
SPECIFICATIONS
Basic Frequency Coverage
*WWV
40-Meter Band
20-Meter Band
15-Meter
Band
*10-Meter
Band
10-Meter
Band
.........
*10-Meter
Band
.........
*10-Meter
Band
.........
*Crystals
not
supplied.
9.5 MC to 10.0 MC
3.5 MC to 4.0 MC
7.0 MC to 7.5 MC
14.0 MC to 14.5 MC
21.0 MC to 21.5 MC
eet 28.0 MC to 28.5 MC
Bee ee eee eee eee e es 28.5 MC to 29.0 MC
29.0 MC to 29.5 MC
29.5 MC to 30.0 MC
Note
-
See
paragraph
5-7
for
additional
information.
IF
Frequencies:
......
pores
Reception:
....
Sensitivity - AM
3 MC to 30 MC
Sensitivity
-
SSB/CW:
.......
3
MC
to
30
MC
Sensitivity
(with
HA-10):
.....
85
KC
to
3
MC
Selectivity:
6c
cdc
ese
&
Stability:
2...
cece
eee
eee
Calibration
Accuracy:
.......
Audio
Power
Output:
........
AVC
Figure
of
Merit:
.......
Power
Source:
.........40-
Power
Consumption:
........
Number
of
Tubes:
..........
Antenna
Input
Impedance:
.....
(High
Frequency)
6.5
MC
to
6.0
MC
(Variable),
1650
KC,
and
50.75
KC.
AM,
CW,
and
Single
Sideband
(SSB).
Less
than
|
microvolt
for
10-DB
signal-to-noise
ratio
(30%
modulation),
Less than 1/2 microvolt.
§
to
10
microvolts.
Variable
in
three
steps
providing
0.5
KC,
2.5
KC,
and
5
KC
at
6 DB
down,
Better
than
300
CPS
after
warmup.
Better
than
2
KC
between
adjacent
100-KC
calibration
points
after
indexing.
More than 50 DB.
Less
than
1/2
microvolt
equivalent
(within
amateur
bands).
3/4
watt
with less
than
10%
distortion.
More than 80 DB.
105
volts
to
125
volts,
50/60
cycles.
70 watts.
14
{one
not
supplied),
plus
four
silicon
diodes.
3.2
ohms
and
500
ohms;
rear-mounted
screw
terminals,
50
ohms
to
2000
ohms;
panel-mounted
jack
accepts
standard
1/4-inch
plug.
50 ohms to 70 ohms unbalanced; rear-mounted RCA-type
phono
jack
accepts
RCA-type
phono
plug.
NOTE:
Chassis
punched
to
accept
Amphenol
Type
SO-239
coaxial
receptacle;
for
use
from
3.0
MC
to
30
MC.
-2-

(orriowaiy
Low Frequency Input:
Remote
Standby
Control:
.....-
Demensions:
Net
Weight:
Shipping Weight:
High impedance to first mixer grid; for use with external-
tunedcircuit from 85 KC to 3.0 MC. RCA-type phono
jack accepts RCA-type phono plug.
Rear-mounted screw terminals.
7-3/4 inches high, 15 inches wide, and 14-3/4 inches deep.
18-1/2 pounds,
21 pounds (approximately).
sozanc proouct
me ross
AUmIFIER
Berecton
aurtiner
am
petecron
ave
aurtirien
Cee
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ave
merrier
rinay
auburn
ayo1o
otter
Figure
2.
Block
Diagram
of
the
Receiver.
TUBES
AND
FUNCTIONS
6DC6
RF
Amplifier
6EA8
Third
Mixer,
SSB-Switching
Crystal
Oscillator
6EA8
First
Mixer,
Cathode
Follower
6BA6
50.75-KC
IF
Amplifier
12AT7
Amateur-Band
Crystal
Oscillator
6BE6
Product
Detector,
BFO
*6EAS
Auxillary
Crystal
Oscillator
6BNS
AM
Detector,
AVC
Amplifier,
AVC
Rectifier
6BAB
8-MC
to
6.5-MC
IF
Amplifier
6Gw8
First
Audio
Amplifier,
Audio
Output
6BE6
Second
Mixer
6AUG
100-KC
Crystal-Calibrator
Oscillator
6EAB
VFO,
Cathode
Follower
Two
each
Silicon
Noise-
Limiter
Diodes,
8DC8
1650-KC
IF
Amplifier
Two
each
Silicon
Power-Supply
Diodes.
*Not Supplied
-3-

SECTION Ili
INSTALLATION
3-1.
UNPACKING.
After
unpacking
the
receiver,
examine
it
for
damage
which
may
have
occurred
in
transit.
Should
any
sign
of
damage
be
apparent,
filea
claim
immediately
with
the
carrier
stating
the
extent
of
damage,
Carefully
check
all
shipping
labels
and
tags
for
instructions
before
removing
or
destroy-
ing
them,
IMPORTANT
To
remove
top
cover,
turn
screws
approximately
one
quarter
turn
counterclockwise,
Do
not
attempt
to
remove
screws.
3-2.
LOCATION.
The
receiver
may
be
placed
in
any
location
that
will
permit
free
air
circulation
through
the
ventilation
holes
and
openings
in
the
cabinet.
Avoid
excessively
warm
locations
such
as
those
near
radiators
and
heating
vents.
Also
avoid
direct
blasts
of
air
from
circulating
fans,
etc.
Do
not
place
speakers
or
any
other
objects
on
the
cabinet
oot
in
a
manner
that
will
impair
natural
venti-
ation,
3-3. ANTENNAS.
The
Model
SX-117
uses
an
input
circuit
de-
signed
for
an
unbalanced
50-ohm
to
70-ohm
input.
Any
of the popular
dipole
or beam
antennas
using
50-ohm
to
70-ohm
coaxial
transmission
line
will
suffice.
It should
be remembered,
however,
that
these
antennas
will
give
optimum
results
over
a
limited
frequency
range
only.
Generally
speaking,
the same
rules
that
apply
to transmitting
antennas
will
hold
true
for receiving
antennas.
For further
information
on this
subject,
refer
to the "Radio
Amateur's
Handbook"
or the
"A.R.R.L.
Antenna
Book,"
both
published
by the American
Radio
Re-
lay
League,
West
Hartford,
Connecticut,
U.S.A,
IMPORTANT
Some form of lightning protection
should be provided which will comply
with local-code requirements,
3-4.
GROUNDS.
All station equipment should be bonded to-
gether
with
heavy
copper
wire
or
braid
and
con-
nected to a cold-water pipe or earth ground, An
external chassis ground terminal is provided on
the rear of the Model SX-117 for this purpose.
SPEAKER
STBY OUTPUT FI
CRYSTAL
LF-ANTENNA
ANTENNA
CHASSIS
OSCILLATOR
‘OUTPUT
500 3.2 GND GND REC 0 FUSE
TAMP
GROUND
o92-orcao
Figure 3. View Showing Rear Chassis Connections.

3-5. POWER SOURCE.
The
SX-117
is
designed
to
operate
from
a
105-volt
to
125-volt,
50/60-cycle,
AC
power
source.
Power
consumption
is
70
watts.
NOTE
If in doubt about your power source,
contact your local power company
prior to inserting the power cordinto
any power outlet. Plugging the power
cord into the wrong source can cause
extensive damage to the unit.
SPEAKER,
A
terminal
strip,
marked
G,
3.2,
and
500,
is
provided
at the rear
of the receiver
for connecting
an external
speaker
or line
(see
figure
3). Any
per-
manent-magnet
type
speaker
witha3,.2-ohm
voice
coil
can
be used
by connecting
the twoleads
from
the
speaker
voice
coil
to the
terminals
marked
3.2
and
G,
If
it
is
desired
to
use
a
speaker
with
a voice-coil
impedance
other
than
3.2
ohms,
a
matching
transformer
should
be employed
to in~
sure
optimum
performance,
The
transformer
should
be
mounted
on
or
near
the
speaker,
should
have
a 500-ohm
primary
impedance,
and
should
have
a secondary
impedance
to match
that
of the
speaker
voice
coil.
Connect
the
primary
of the
matching
transformer
to the
terminals
marked
500
and
G and the secondary
to the speaker
voice
coil
terminals,
3-6.
SPEAKER
HT 328 - HT37
SKIO1~_SX IM ~ SxUIS.
The
Hallicrafters
Model
R47
Speaker
is
particularly
suited
for
voice
and
CW
use.
Model
R48A
Speaker,
with
its
two-position
VOICE-FI-
DELITY
switch
will
give
excellent
results
for
all
modes
of
operation,
The
leads
of
either
speaker
are
to
be
connected
to
the
terminals
marked
3.2
and
G.
3-7. HEADPHONES.
The
headphone
jack
marked
PHONES
is
lo-
cated
on
the
front
panel
and
is
wired
so
that
the
3,2-ohm
speaker
output
is
automatically
disabled
when
the
headphones
are
inserted.
The
headphone
impedance
is
not
critical,
and any
headphones
ranging
in
impedance
from
50
ohms
to
2000
ohms
will
provide
satisfactory
performance.
It
should
be
noted
that,
although
insertion
of
the
headphone
plug
into
the
front
panel
jack
will
silence
the
3.2-ohm
speaker
output,
the
500-ohm
output
will
remain
in
operation
at
all
times,
3-8. REMOTE RECEIVE-STANDBY
SWITCHING.
The
receiver
may
be
disabled
from
a
re-
mote
location
by
removing
the
jumper
between
the
terminals
marked
STANDBY
and
G
on
the
rear
of
the
chassis
and
then
connecting
a
SPST
switch
or
relay
between
these
terminals,
The
switch
or
re-
lay
contacts
should
be
so
wired
astoclose
in
Re-
ceive
and
open
in
Transmit.
The
receiver
may
also
be
disabled
in
Trans-
mit
by
turning
the
RF
GAIN
control
to
0
(fully
counterclockwise),
NOTE: DOTTED LINES INSIDE BOXES
DENOTES INTERNAL WIRING
HT338, HT 41, OR
TYPICAL LINEAR AMPL.
CONTROL,
JO GRID
RETURN
OPERATING
BIAS.
RESISTOR
STANDBY
BIAS,
RESISTOR
ANTENNA
ANTENNA
Gaal {NOT SUPPLIED }
CHANGE OVER
RELAY
NOTE-ALL CHASSIS SHOULD
NOTE: USE OF ‘0K POT FOR 2€ @ONDED ToseTHER = yy
MONITERING LEVEL OPTIONAL AND TD EARTH OR iid:
WATER PIPE, GROUND.
082-o4808
Figure 4. Typical Station Setup.
-5-

nr aN
hallicratiers
presexgcich
oe
7
ano
secfcTae
nots”
MODEL
SX-1T
raacrioa
LI
o92-c1s915
Figure
5.
Front
Ponel
View
of
Receiver.
SECTION
IV
FUNCTIONS
OF
OPERATING
CONTROLS
4-1.
RF
GAIN
CONTROL.
The
RF
GAIN
control
varies
the
gain
of
the
RF
amplifier
and
the
50.75-KC
IF
amplifier.
Max-
imum
sensitivity
is
obtained
with
the
control
set
at
10
(fully
clockwise).
In
this
position,
the
tubes
being
controlled
are
operating
at
maximum
gain
with
minimum
cathode
bias.
As
the
control
is
ro-
tated
counterclockwise,
the
cathode
bias
is
in-
creased
with
a
resultant
decrease
In
gain.
The
normal
setting
of
the
RF
GAIN
control
will
vary
with
conditions.
When
searching
for
weak
signals,
the
control
should
be
well
advanced,
When
copying
strong
signals
under
erowded
or
noisy
conditions,
it
may
be
found
desirable
to
reduce
the
RF
GAIN
control
setting.
It
should
be
remembered
that
the
S-Meter
calibration
will
be
correct
only
with
the
REGAIN
control
fully
advanced
to
10.
AVC
is
automatically
controlled
by
the
RF
GAIN
control
so
that
it
is
not
necessary
to
dis-
able
the
AVC
circuitry
for
any
mode
of
reception.
4-2.
BAND
SELECTOR
CONTROL.
The
BAND
SELECTOR
control
operates
the
pandswitch
to
place
the
proper
crystal
and
coils
into
the
circuit
to
cover
the
desired
frequency
range.
“6=
It
should
be
noted
that
several
bandswitch
positions
are
identified
by
a
red
dot,
When
the
switch
is
rotated
to
one
of
these
positions,
the
red
dial
scale
should
be
used.
In
the
LF
position,
the
bandswitch
discon-
nects
the
internal-tuned
circuits
and
connects
the
first
mixer
grid
to
the
LF
INPUT
jack
on
the
rear
panel.
4-3.
PRESELECTOR.
The
PRESELECTOR
control
provides
pre-
cise
tuning
of
the
antenna
and
mixer
coils
to
give
maximum
gain
andoptimum
signal-to-noise
ratio.
It
also
allows
coverage
of
the
entire
3.0-MC
to
30-MC
range
(see
paragraph
5-7).
NOTE
Care
should
be
exercised
when
setting
the
PRESELECTOR
control
on
the
40-
meter
(7.0
MC)
or
WWV
bands.
It
is
possible
to
tune
the
PRESELECTOR
control
to
the
6.5-MC
to
6.0-MC
first
IF
frequency.
The
correct
setting
for
the
40-meter
band
is
indicated
by
the
block
marked
40.
The
correct
setting
for
WWV
(9.5
MC
to
10MC)
willbe
be-
tween
8
and
9
on
the
PRESELECTOR
logging
scale.

Under certain conditions where excessive
noise or interference is encountered, it may be
found desirable to slightly detune the PRESEL-
ECTOR
control
for
optimum
reception.
4-4, AF (AUDIO) GAIN CONTROL.
The AF GAIN control adjusts the audio out-
put level at the speaker terminals and PHONES
jack. Clockwise rotation increases the signal
voltage applied to the grid of the audio am-
plifier, thus increasing the audio output.
4-5.
SELECTIVITY
SWITCH.
The SELECTIVITY switch is used to vary
the IF bandwidth to suit receiving conditions.
Three degrees of selectivity are available, rang-
ing from 500 CPS for CW reception under
crowded-band conditions to 5 kilocycles for maxi-
mum fidelity on voice or music-modulated signals
where conditions permit. The three positions are
marked on the front panel and indicate the 50.75-
KC IF bandwidth at the 6-DB points. See figure
6 for typical IF selectivity curves,
The recommended positions for the various
modes of operation are as follows:
cw 0.5 KC or 2,5 KC
SSB 2.5 KC
AM 2.5 KC or 5,0 KC
4-6.
FUNCTION
SWITCH.
The FUNCTION switch is afour-position ro-
tary switch performing the following functions:
Position Function
OFF.
+
disconnects
the
117-voit,
60-
cycle, AC power,
a. Connects the 117-volt, 60-
cycle, AC power.
b. Disables the BFO.
¢, Connects audio to the enve-
lope detector.
d. Selects fast-attack, fast-re-
lease AVC.
e. Connects the 1700-KC side-
band~switching crystal.
USB. .... a. Connects audio tothe product
detector.
b. Energizes the BFO.
DB ATTENUATION
KC OFF RESONANCE
toa 6 4
2+0~2 4 6 3 10
J
o92-016760
Figure 6. IF Selectivity Curves.
c.
Selects
fast-attack,
slow-
release
AVC,
d. Connects the 1700-KC side-
band-switching crystal.
a. Connects audio to the pro-
duct
detector.
b.
Energizes
the
BFO.
c. Selects fast-attack, slow-
release AVC.
d. Connects 1600-KC sideband-
switching crystal.

To
illustrate
how
selectable-sideband
re-
ception
is accomplished,
a numerical
example
is
given.
Consider
an incoming
signal
at 7000
KC,
modulated
1 KC.
Since
modulation
of a carrier
causes
the
generation
of sideband
frequencies
mumerically
equal
to the
carrier
frequency
plus
or minus
the modulation
frequency,
the incoming
signal
consists
of the
carrier
at 7000
KC,
a
lower
sideband
at 6999
KC,
and
an upper
side-
band
at 7001
KC.
See
figure
7A.
The
incoming
signal
is
first
heterodyned
with
the
output
of the first
conversion
oscillator
in the first
mixer.
The
first
conversion
oscillator
operates
at a frequency
higher
than
the incoming
signal
by an amount
equal
to the
first
IF fre-
quency
of 6.500
MC
{variable
IF).
As a result
of
this,
three
new
lower
frequencies
are produced
in the
output
of the
first
mixer:
the
carrier
at
6.500
MC,
the
lower
sideband
at 6.501MC,
and
the
upper
sideband
at 6.499
MC.
These
signals
are
amplified
by the
6.500-MC
to 6.000-MC
IF
stage
and
then
heterodyned
with
the
output
of
the
VFO
(4.85
MC
to 4.35
MC)
in the second
mixer.
Three
new
lower
frequencies
are
again
produced
in the
output
of this
mixer
stage:
a
center
frequency
of 1650
KC,
a lower
sideband
of 1651
KC,
and
an upper
sideband
of 1649
KC.
These
signals
are
amplified
by the
1650-KC
IF
amplifier
and
fed
to the third
mixer,
where
they
are
heterodyned
with
the
output
of either
the
1600-KC
(lower
sideband)
or the 1700-KC
(upper
sideband)
crystal-controlled
third
conversion
os-
cillator.
When
the
FUNCTION
switch
is placed
in the LSB
position,
three
new
lower
frequencies
are
produced:
the
carrier
frequency
at
50
KC,
the
lower
sideband
at
51
KC,
and
the
upper
sideband
at
49
KC.
By
referring
to
figure
7D,
it
can
be
seen
that
the
lower
sideband
falls
within
the
IF
passband
and
the
upper
sideband
is
rejected.
When
the
FUNCTION
switch
is
placed
in
USB
position,
the
carrier
frequency
remains
at
50
KC
but
the
sidebands
are
reversed
in
the
heter-
odyning
process.
The
upper
sideband
will
now
be
51
KC
and
falls
within
the
IF
passband,
while
the
lower
sideband
will
appear
at
49
KC
and
be
rejected,
4-7,
NOTCH
FREQ
(FREQUENCY)
CONTROL.
The
NOTCH
FREQ
control
varies
the
notch
frequency
within
the
50.75-KC
IF
passband
andis
very
useful
in
attenuating
an
undesirable
hetero-
dyne.
Since
the
notch
width
is
quite
narrow,
it
is
essentially
a
single-frequency
device
and
cannot
attenuate
more
than
one
heterodyne
if
the
hetero-
dynes
are
separated
in
frequency
by
more
than
500
CPS.
The
NOTCH
FREQ
control
is
very
effective
when
using
exalted
carrier
reception
(AM
with
BFO
on).
The
notch
control
is
adjusted
to
approxi-
mately
50
KC
so
that
the
incoming
signal
carrier
is
removed.
This
will
remove
the
low-frequency
heterodyne
which
may
be
heard
if
the
receiver
is
not
tuned
to
exactly
zero
beat
with
the
incoming
signal.
The
AM
signal
under
these
conditions
will
tune
similar
to
double-sideband
suppressed
car-
rier
and
may
be
received
in
the
USB
(upper-
sideband)
or
the
LSB
(lower-sideband)
position.
A 8
INCOMING SIGNAL OU'PUT OF IST MIXER
were
SB LOVES SIDEBANO
USHeUPPER SIDEBARD
NO TD SEALE ILLUSTRATION aks
‘SUTPUT OF 26D MEXER
¢
°
E
38D
CONY
OSCILLATOR
35RD
CONY
OSCILLATOR
FREQ=
160085
FREQ
=|70QKC
OUTPUT OF 380 MIXER
992 218816
Figure
7.
Selectable-Sideband
Response
Curves.

= Fe norcH FREQUENCY RANCE
Fa
4 0
4“
a
3NC_CURVE om
L
1
WTHOUT KOCH —#F
40
OB ATTENUATION
a0
092-203878
Figure
8. IF
Selectivity
with
Notch.
The
notch
calibration
is
quite
accurate
and
may
be used
as a guide
in determining
where
the
NOTCH
FREQ
control
should
be set to attenuate
an
interfering
signal,
provided
the
BFO
fre-
quency
is set as described
under
BFO
operation.
For
example,
if the heterodyne
is approximately
1000
CPS,
the
null
point
would
be near
51 KC,
If
the
heterodyne
is 2000
CPS,
the null
point
would
be near
52 KC,
ete.
4-8. BFO CONTROL.
The
BFO
control
is
a
front-panel
adjust-
ment
which
allows
the beat
frequency
oscillator
to be set at exactly
50 KC.
NOTE
The BFO control should not be used
for tuning purposes as the BFO fre-
quency must be maintained if optimum
performance is to be obtained.
The
correct
setting
will
be
near
the
point
where
the
knob
and
panel
marks
coincide.
The
exact
point
may
be found
by placing
the FUNCTION
switch
in USB,
the SELECTIVITY
control
at 5.0
KC,
and
tuning
in a CW signal
or crystal
calibrator
to near
zero
beat.
Switch
the FUNCTION
control
to
-9-
LSB.
The
beat
note
should
not
change
frequency.
If
it
does,
adjust
the
BFO
control
until
the
beat
note
frequency
remains
the
same
in the
USB
or
LSB
position.
The
control
should
always
be
at
this
point,
4-9. TUNING CONTROL.
The
TUNING
control
is
used
to
vary
the
fre-
quency
of the
VFO
to allow
reception
of the de-
sired
signal.
It also
rotates
the dial
past
a station-
ary
pointer
to indicate
the frequency
in kilocycles,
It
should
be
noted
that
two
scales
appear
on
the
dial:
0
to
500
KC
and
500
KC
to
1000
KC,
If
the
band
being
tuned
starts
at
the
even
megacycle,
(e.g.,
7.0),
the frequency
is read
on the 0 to 500-
KC
scale;
if
the
band
starts
on
0,5
megacycle
(e.g.,
3.5),
the frequency
is read
on the 500-KC
to 1000-
KC scale,
If
the
BAND
SELECTOR
is
set
opposite
ared
dot,
the
red
dial
scale
should
be used
to indicate
the correct
frequency.
The
skirt
on
the
TUNING
knob
is
divided
into
15 segments.
Each
division
will
represent
approximately
one
kilocycle
of frequency
change.
4-10.
CAL
RESET
CONTROL.
The
CAL
RESET
control
operates
avariable
trimmer
to
allow
the
VFO
calibration
to
be
set
exactly
to frequency
at any
check
point.
If
the
dial
calibration
does
not
agree
with
the
frequency
of
a
known
signal,
such
as
a
crystal
calibrator,
the
CAL
RESET
control
should
be
adjusted
as
necessary
to
correct
the
calibration
error.
4-11.
OFF-NL-CAL
SWITCH.
The
OFF-NL-CAL
control
is
a
three-posi-
tion
rotary
switch
performing
the
following
func-
tions:
LL
OFF
-
In
this
position,
both
the
noise
limiter
and
100-KC
crystal
calibrator
circuits are disabled.
2, NL - In this position, the noise limiter
is placed in operation (see paragraph
5-6}.

8.
CAL-JIn
this
position,
the
100-KC
crystal
calibrator
is
placed
in
oper-
ation
to
provide
marker
signals
at
every
100-KC
point
on
the
dial.
NOTE
The
100-KC
crystal
calibrator
should
not
be
left
in
the
ON
position
after
dial
calibration
is
completed.
Under
certain
conditions
it
can
cause
spur-
ious
responses
to
be
developed.
4-12.
XTAL
SELECTOR
SWITCH.
The
XTAL
SELECTOR
switch
is
a
five-
position
rotary
switch
performing
the
following
functions:
1
NORMAL
-
In
the
NORMAL
position,
plate
voltage
is
removed
from
the
not
supplied)
and
the
receiver
will
operate
on
the
ranges
indicated
by
the
BAND
SELECTOR
knob,
2.
1
AND
2
-
Positions
1
and
2
of
the
XTAL
SELECTOR
switch
will
disable
the
12AT7
first
crystal
oscillator,
apply
voltage
to
the
6EA8
auxiliary
os-
cillator,
and
select
crystals
inserted
in
auxiliary
crystal
sockets
1
or
2.
Use
only
type
CR-18/U
crystals
whose
frequencies
fall
between
6.5
MC
and
20.00
MC
(inclusive)
in
these
sockets
{see
paragraph
5-7).
3.
3
AND
4
-
Positions
3
and
4
alsodis-
able
the
12AT7
first
crystal
oscil-
lator,
apply
plate
voltage
to
the
6EA8
auxiliary
oscillator,
and
select
cry-
stals
inserted
in
auxiliary
crystal
sockets
3
and
4,
Use
only
type
CR-
23/U
crystals
whose
frequencies
fall
between
20,5
MC
and
34.0
MC
(inclu-
sive)
in
these
sockets
(see
paragraph
auxiliary
crystal
oscillator
(6EA8
5-7).
SECTION
V
OPERATION
5-1,
SINGLE-SIDEBAND
RECEPTION.
XTALCAL..
OFF
Set
the
front
panel
controls
as
outlined
below,
RFGAIN........
Usually
at
10
(maybe
reduced
as
noise
and
QRM
dictate),
NOTE
S-Meter
reading
will
be
correct
only
with
the
RF
GAIN
control
set
at
10.
BAND
SELECTOR.
.
To
desired
band.
AUDIO
GAIN
.....
Approximately
2.
SELECTIVITY
....
2.5
KC.
FUNCTION
......
Usually
LSB
for
80
and
40
meters
and
USB
for
20,
15
and10
meters,
Center
or
0
position
(do not
use
BFOcon-
trol
for
tuning
pur-
poses).
NOTCH.........
OFF
PRESELECTOR
.
Peaked
for
maximum
signal.
-10-
Use as noise condi-
tions
dictate,
NL
(Noise
Limiter).
As
desired.
Slowly
adjust
the
TUNING
control
until
the
voice
modulation
sounds
natural.
Peak
the
PRE-
SELECTOR
for
maximum
S-Meter
indication
and
adjust
the
AUDIO
GAIN
control
as
desired.
If
an
undesirable
heterodyne
appears,
adjust
the
NOTCH
control
for
maximum
attenuation,
It
should
be
remembered
that
an
SSB
signal
will
convey
intelligence
only
when
the
correct
sideband
position
has
been
selected
onthe
FUNC-
TION
switch.
If
the
signal
does
not
tune
in
pro-
perly,
change
the
FUNCTION
switch
to
the
other
SSB
position
and
retune.
The
RF
GAIN
control
should
normally
be
set
at
10
(maximum
sensitivity),
Under
adverse
conditions,
it
may
be
found
advantageous
to
reduce
the
RF
GAIN
to
improve
reception.
It
should
be
remembered
that,
as
the
RF
GAIN
is
reduced,
the
AVC
will
be
reduced.
Also,
correct
S-Meter
readings
will
be
indicated
only
with
the
RF
GAIN
at
10.

5-2. CW RECEPTION.
Set
all
controls
as
described
under
single-
sideband
reception
except
for
the
SELECTIVITY
and
noise
limiter
controls.
The
SELECTIVITY
control
will
usually
be
in
the
0.5
KC
position
for
CW.
The
NL
(noise
limiter)
can
be
used
to
ad-
vantage
at
all
times
in
CW
reception
and
will
be
very
effective
in
reducing
impulse
noise,
key
clicks,
ete,
The
NOTCH
control
should
be
used
as
necessary
to
attenuate
interfering
signals
and
heterodynes,
The
RF
GAIN
control
should
be
adjusted
as
conditions
dictate
for
best
reception.
NOTE
Do
not
use
the
BFO
control
for
tuning
purposes.
5-3. AM RECEPTION.
Set
all
controls
as
described
under
single-
sideband
reception
except
for the
FUNCTION
con-
trol,
The
FUNCTION
control
should
be
placed
in
the
AM
position.
The
SELECTIVITY
control
may
be
placedin
the
5.0-KC
position
for
improved
fidelity
where
band
conditions
permit.
The
RF
GAIN
control
will
normally
be
set
at
10
for
AM
reception
except
on
extremely
strong
local
signals.
If
the
NL
(noise
limiter)
is
used
on
AM,
distortion
can
be
reduced
by
reducing
the
RF
GAIN
control
setting
to
the
lowest
practical
level,
The
NOTCH
control
should
be
used
as
nec-
essary
for
removing
undesirable
heterodynes,
5-4. EXALTED CARRIER AM RECEPTION.
In
short-wave
reception,
it
frequently
hap-
pens
that
transmission
conditions
are
different
for
waves
of
slightly
different
frequencies.
As
a
result,
in
the
case
of
voice
modulated
transmis-
sions,
AM
particularly,
which
involve
sideband
frequencies
differing
slightly
from
the
carrier
frequency,
the
carrier
and
sideband
components
may
not
be
received
in
the
same
relative
ampli-
tudes
and
phases
that
were
present
at
the
trans-
mitter,
This
effect,
known
as
selective
fading,
causes
severe
distortion
of
the
signal.
This type of distortion can be reduced con-
siderably by utilizing the selectable-sideband
feature of the Model SX-117 receiver operating in
an exalted carrier mode (i.e., the transmitted car-
rier is positioned out of the receiver's IF pass-
band along with one sideband, producing a sup-
pressed carrier single-sideband signal). The car-
rier is subsequently reinserted by the receiver's
BFO and the signalisdetectedinthe same manner
as a single-sideband signal.
All controls should be set as described un-
der single-sideband reception. Place the FUNC-
TION switch in the SSB position that gives best
reception. In addition, the NOTCH control should
be adjusted to the carrier frequency (approxi-
mately 50 KC) to null out the incoming signal
carrier.
If noise conditions warrant, the noise limiter
should be used.
5-5. USE AND ADJUSTMENT OF 5-METER,
The S-Meter provides a visual means of
determining whether or not the receiver is
properly tuned, as well as providing an indication
of the signal strength. The S-Meter is calibrated
in S-units to 9 and in decibels to 70 DB above S9,
The meter calibration will be correct only when
the RF GAIN control is set at 10 (fully clockwise).
$9 represents a 50-microvolt signal at the
antenna input, Each S-unit represents approxi-
mately 6 DB change in signal strength,
For
accurate
readings,
the
meter
zero
should
be checked
periodically.
To
adjust
the
electrical
zero
on the
meter,
turn
the RF GAIN
control
to 0 (fully
counterclockwise),
Rotate
the
Meter
Zero
control
asnecessary
so that
the meter
pointer
is aligned
with
the last calibration
mark
on
the left
side
of the meter
scale.
IMPORTANT
To remove top cover, turn screws
approximately one quarter turn
counterclockwise,
Do not attempt to remove screws,
The Meter Zero control may be found di-
rectly
under
the
rear
of
the
meter
housing.
CAUTION
Do not disturb the adjustment of the
Notch Depth or Factory Gain controls.
5-6. USE OF NOISE LIMITER {NL}.
The noise limiter is an IF-type limiter and
is very effective in reducing impulse-type noise
particularily on SSB and CW. It will be found use-
ful on AM as well. Recommended use is as fol-
ows:

For
CW
Operation:
The noise limiter should be on at all
times for elimination of impulse noise
and key clicks.
For
SSB
Operation:
Use the noise limiter as noise condi-
tions
dictate.
For
AM
Operation:
Use the noise limiter as noise condi-
tions dictate, It will be noticed that
the
noise
limiter
will
introduce
consi-
derable
distortion
on
a
fully
modu-
lated
AM
signal.
Distortion
may
be
reduced by decreasing the RF GAIN
control setting.
5-7.
GENERAL
COVERAGE
OPERATION.
The
Model
SX-117
Receiver
may
be
used
on
most
frequencies
from
85
KC
to
30.0
MC
by
inserting
the
correct
heterodyne
crystals
into
the
auxiliary
oscillator
sockets,
The
frequencies,
whose
use
is
not
recommended,
are
1600
KC,
1650
KC,
1700
KC
and
the
5.5-MC
to
7.0-MC
range.
In the low frequency range (i.e,, 85 KC to
3.0 MC), an external-tuned circuit (Model HA-10)
should be connected between the antenna and the
LF INPUT jack (see figure 19).
NOTE
In primary service areas of high-
power broadcast stations, good re-
sults can be obtained by connecting
an antenna directly to the LF INPUT
jack,
The
following
chart
contains
the
informa-
tion
needed
to
cover
the
85-KC
to
30-MC
range:
T
Crystal
]
Signal
Crystal
Crystal
Selector
Preselector
|
Dial
Band
Frequency
Frequency
Type
&
Socket
Calibration
|
Scale
Selector
85
KC
to
500
KC
CR-18/U
lor2
Use
Black
LF
500
KC
to
1.0
MC
7.0
MC
CR-18/U
lor
2
Red
LF
1.0
MC
to
1.5
MC
7.5
MC
CR-18/U
lor
2
Model
Black
LF
1.5
MC
ta
2.0
MC
8.0
MC
CR-18/U
lor
2
Red
LF
2.0
MC
to
2.56
MC
8.5
MC
CR-18/U
lor
2
HA-10
Black
LF
2.5
MC
to
3.0
MC
CR-18/U
lor
2
Red
LF
3.0
MC
to
3,5
MC
CR-18/U
3.5
MC
to
4.0
MC
--
--
Normal
[eq
Red
3.5
4.0
MC
to
4.5
MC
10.5
MC
CR-18/U
lor2
xi
Black
3.5
4.5
MC
to
5.0
MC
ie
11.0
MC
CR-18/U
lor2
2
Red
7.0
5.0
MC
to
5.5
MC
11.5
MC
CR-18/U
lor
2 3
Black
7.0
7,0
MC
to
7.5
MC
-
=s
Normal
[40]
Black
7.0
7.5
MC
to
8.0
MC
14.0
MC
CR-18/U
lor
2
7
Red
7.0
8.0
MC
to
8.5
MC
14.5
MC
CR-18/U
lor
2
7-1/2
Black
7.0
8.5
MC
to
9.0
MC
15.0
MC
CR-18/U
lor2
8
Red
7.0
9.0
MC
to
9.5
MC
15.5
MC
CR-18/U
lor2
8-1/2
Black
7.0
9.5
MC
to
10
MC
--
=
Normal
9
Red
7.0
10
MC
te
10.5
MC
16.5
MC
CR-18/U
lor2
9-1/2
Black
7.0
10.5
MC
to
11
MC
17.0
MC
[
CR-18/U
lor2
4-1/2
Red
14
11
MC
to
11.6
MC
17,5
MC
CR-18/U
lor2
5
Black
14
11.5
MC
to
12
MC
18.0
MC
CR-18/U
lor2
5-1/2
Red
14
12
MC
to
12.5
MC
18.5
MC
CR-18/U
lor2
6
Black
14
242-

[ Crystal
Signal Crystal Crystal Selector Preselector Dial Band
Frequency Frequency Type & Socket Calibration Scale Selector
12.5 MC to 13 MC 19.0 MC CR-18/U lor2 6-1/2 Red | 44
13
MC
to
13.5
MC
19.5
MC
CR-18/U
lor2
7
Black
14
13.5 MC to 14 MC 20.0 MC CR-18/U lor2 7 Red 14
14.MC to 14.5 MC -- - Normal [20] Black 14
14,5
MC
to
15
MC
21.0
MC
CR-23/U
3or4
7-1/2
Red
14
15
MC
to
15.5
MC
21.5
MC
CR-23/U
eor4d
q-1/2
Black
14
15.5 MC to 16 MC 22,0 MC CR-23/U 3or4 8 Red 14
16 MC to 16,5 MC 22.5 MC CR-23/U sor4 8 Black 14
16.5
MC
to
17
MC
23.0
MC
CR-23/U
3or4
8-1/2
Red
14
17 MC to 17.5 MC 23.5 MC CR-23/U 3or4 8-1/2 Black 14
17.5 MC to 18 MC 24.0 MC CR-23/U 3or4 9 Red vt 14
18
MC
to
18,5
MC
24.5
MC
CR-23/U
3or4
7
Black
21
18.5 MC to 19 MC 25.0 MC CR-23/U 3or4 if Red 21
19 MC to 19.5 MC 25.5 MC CR-23/U 3or4 7-1/2 Black 21
19.5 MC to 20 MC 26.0 MC CR-23/U 3or4 7-1/2 Red 21
20 MC to 20.5 MC 26.5 MC CR-23/U 3or4 8 Black 21
20.5 MC to 21 MC 27.0 MC CR-23/U 3or4 8 Red 21
21 MC to 21.5 MC ts “ Normal [15] Black 21
21,5 MC to 22 MC 28.0 MC CR-23/U 3 or 4 8-1/2 Red at
22 MC to 22.5 MC 28.5 MC CR-23/U 3or4 8-1/2 Black 21
22.5
MC
to
23
MC
29.0
MC
CR-23/U
3or4
9
Red
21
23 MC to 23.5 MC 29.5 MC CR~-23/U 3or4 9 Black 21
23.5 MC to 24 MC 30.0 MC CR-23/U 3or4 9-1/2 Red 21
24 MC to 24.5 MC 30,5 MC CR-23/U 3or4 9-1/2 Black 21
24.5 MC to 25 MC 31.0 MC CR-23/U Sor4 7-1/2 Red 28.0 |
25 MC to 25.5 MC 31.5 MC CR-23/U 3or4 8 Black 28,0
25.5 MC to 26 MC 32.0 MC CR-23/U 3or4 8 Red 28.0
28 MC to 26.5 MC 32.5 MC CR-23/U gor4 8-1/2 Black 28.0
26.5 MC to 27 MC 33.0 MC CR-23/U 3or4 8-1/2 Red 28.0
27 MC to 27.5 MC 33.5 MC CR-23/U 3or4 9 Black 28.0
27.5 MC to 28 MC 34.0 MC CR-23/U 3or4 Red 28.0
28 MC to 28.5 MC =. =e Normal Black 28.0
+
28.5 MC to 29 MC -- sd
4.
29 MC to 29.5 MC - --
+
29.5 MC to 30 MC -- es

Crystals
for
General
Coverage
Operation
should
be ordered
through
an authorized
Halli-
crafters
Dealer,
allowing
reasonable
time
for
delivery.
Because
of the large
quantity
of crystal
required
to
satisfy
varied
user
requirements,
neither
The
Hallicrafters
Company
nor
its
dealers
will
normally
stock
crystals
for
general
coverage
service.
Substitution
of
crystal
types
other
than
Specified
should
be
avoided.
Proper
operation
and
frequency
correlation
is
dependent
on
precise
characteristics
of
the
CR-18/U
and
CR-23/U
types
as
listed,
NOTE
Those crystals which are shipped with
the Model SX-117 Receiver and the ad-
ditional 10-meter and WWV crystals
are available at The Hallicrafters
Company. See the Service Repair
Parts
List
for
part
numbers
of
these
crystals.
5-8.
USE
OF
VFO
AS
CRYSTAL-LOCKED
OSCILLATOR.
The
VFO
(variable
frequency
oscillator)
may
be
used
as
a
crystal-controlled
oscillator
for
fixed-frequency
operation.
This
may
be
accomplished
as
follows:
1,
Insert
a
4,5-MC
type
CR-18/Ucrystal
in
the
VFO
crystal
socket,
SOl.
2.
Add
6.15
megacycles
(IF
frequency)
to
the
desired
signal
frequency.
This
will
determine
the
heterodyning
crystal
If
the
heterodyning
crystal
frequency
is
20
MC
or
less,
specify
type
CR-
18/U
and
insertin
auxiliary
oscillator
crystal
socket
1
or
2.
4, If the heterodyning crystal frequency
is more than 20 MC, specify type
CR-23/U and insert in auxiliary os-
cillator crystal socket 3 or 4.
5. The PRESELECTOR calibration and
BAND SELECTOR setting may be de-
termined from the general -coverage
chart (paragraph 5-7),
6. The VFO dial should be set at approx-
imately 375. Slight frequency warping
may be achieved by moving the dial
Slightly from this point.
Example 1 - The desired signal frequency is
2.950 MC; the heterodyning crystal frequency is
12.950 MC + 6.15 MC=19.100MC. From the gen-
eral-coverage chart, it can be determined that,
for a signal frequency of 12.950 MC, the PRE-
SELECTOR should be set at 6 1/2 and the BAND
SELECTOR should be at 14, The correct crystal
would be a 19.100-MC type CR-18/U crystal in-
serted in either crystal socket ! or 2.
Example 2 - The desired signal frequency is
18.4 MC; the heterodyning crystal frequency is
18.4 MC + 6.15 MC = 24.55 MC, From the general
coverage chart, it can be determined that, for a
Signal frequency of 18.4 MC, the PRESELECTOR
should be set at 7 and the BAND SELECTOR at
21. The correct crystal would be a 24,55-MC
type CR-23/U crystal inserted in either crystal
frequency.
socket
3
or
4,
SECTION
VI
ALIGNMENT
6-1.
GENERAL.
2
Vacuum
tube
voltmeter
(VTVM).
Alignment
should
not
be
attempted
until
all
other
possible
causes
of
faulty
operation
have been
exhausted,
NOTE
Do
not
make
any
adjustments
unless
the
operation
of
this
receiver
is
fully
understood
and
adequate
test
equip-
ment is available.
6-2.
TEST
EQUIPMENT
REQUIRED.
1.
Signal
generator
with
50-KC
to
30-MC
coverage,
a
calibrated
output
level
meter,
anda
50-chm
termination.
-14-
3
Output
meter
(or
AC
scale
of
VTVM),
Ifa VTVM
is used,
connect
it to terminals
500
and
G and terminate
the output
with
a 500-ohm,
2-watt,
dummy
load.
4.
stals,
5. Alignment tool, such as GENERAL
CEMENT
#8606,
and
a
small
screwdriver.
9.5~MC and 18-MC type CR-18/U cry-
INITIAL CONTROL SETTINGS.
BAND SELECTOR. As indicated in chart.
AUDIO AND RF...
GAIN
6-3.
10 {maximum).

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Top View of Receiver Chassis.
-15-
Figure 9.

SELECTIVITY.
...
As
indicated
in
chart.
BEOp2h09
xg
Ss.
0
(center
point).
FUNCTION......
AM
IMPORTANT
TUNING........
As
indicated
on
chart,
To
remove
top
cover,
turn
screws
NOTCH
........
OFF,
approximately
one
quarter
turn
coun-
terclockwise.
XTAL
CAL-NL,
,.
OFF.
-
Do
not
attempt
to
remove
screws,
6-4. ALIGNMENT PROCEDURE.
Generator
Frequency Band
50.75 KC un- 80 Meters
mod, (critical)
Output
Connections
Signal Generator
Connections
Step
Selectivity
VTVM DC probe
High side directly
to
Pin
6
of
V10
to Pin 2 of V8
Adjust
top
cores
of
T5, T6,
T7,
and
T8
for
maximum
indication.
Reduce
generator
output
as
necessary
to
maintain
approximately
a
l-volt
reading
on
VTVM.
(Use
screwdriver.)
80 Meters
Output
meter
across
appro-
priate
speaker
output
terminals
1650 KC, 400
cycles, 30%
mod.
High Side directly
to Pin 7 of V5
Slowly
tune
generators
through
1650
KC
to
determine
center
of
IF
passband,
Set
generator
at
center
of
IF
passband
and
adjust
generator
output
to
maintain
approximately
a
1/2-watt
receiver
output,
Adjust
top
and
bottom
cores
of
T3
and
T4
for
maximum
receiver
output.
80
Meters
Output
meter
across
appro-
priate
speaker
output
terminals
High side directly
to Pin 2 of V2
6.050 MC, 400
cycles, 30%
mod.
just
receiver
tuning
until
a
signal
is
heard
at
approximately
3.95
MC.
Adjust
top
cores
of
TL
for
maximum
receiver
output.
4
High
side
directly
6,45
MC
mod,
80
Meters
Output
meter
5.0
KC
to
Pin
2
of
V2
across
appro-
priate
speaker
output
terminals
Adjust
receiver
tuning
until
a
signal
is
heard
at
approximately
3.55
MC.
Adjust
middle
and
rear
trimmers
C15B
and
C15D
for
maximum
receiver
output.
Repeat
core
and
trimmer
adjustments
until
Ino
further
increase
in output
is noted.
6-5.
ADJUSTMENT
OF
CRYSTAL-
separate
adjustments
(i.e.,
80
M
and
10
M-1,
CONTROLLED
FIRST
CONVERSION
40
M
and
10
M-2,
etc).
In
all
cases,
the
top
core
OSCILLATOR.
will
be
the
low
frequency
adjustment
andthe
10
M
adjustment
will
be
the
bottom
core
(see
figure
10),
All
adjustments
may
be
made
from
the
top
or
All
of
the
coil
forms
in
this
group,
except
bottom
of
the
chassis
when
using
an
alignment
the
WWV
coil,
have
two
separate
coils
and two
tool
such
as
General
Cement's
No.
8606.
16-

O92-o1se29
Figure
10.
Crystal
Oscillator
Coil
Locations.
Connect
a
VTVM
(set
to
read
negative
DC
voltage
on 10-volt
scale)
at point
where
R30
(1
megohm)
connects
to terminal
strip
near
V2.
Starting
with
80 M, adjust
each
core
in order
of
increasing
frequency,
for
maximum
voltage
in-
dication
as
the
BAND
SELECTOR
switch
is
ad-
vanced
through
the
various
ranges.
NOTE
After all adjustments have been made,
it is permissible to warp the crystal
frequency by rotating the appropriate
core slightly to allow more accurate
band-to-band calibration, consistent
with positive oscillator start as the
BAND SELECTOR is rotated through
each range.
6-6, PRESELECTOR ALIGNMENT.
To
align
the
PRESELECTOR,
9.5-MC
and
18.0-MC
type
CR-18/U
crystals
will
be
required.
Insert the 9.5-MC crystal in Auxiliary Oscillator
socket No. 1 and the 18-MC crystal in Auxiliary
Oscillator socket No. 2,
Step 1
a.
Set
generator
frequency
to
3.0
MC.
b Set receiver TUNING dial to 0.
c. Set BAND SELECTOR to 3.5.
d.
Set
PRESELECTOR
to
0
(Maximum
capacity).
e Set XTAL SELECTOR to 1.
i.
Connect
generator
to
antenna
input.
Adjust
L5
(antenna
coil)
and
L6
(mixer
coil)
for
maximum
receiver
output.
17:
a
Set
generator
frequency
to
11.5
MC.
b.
Leave
receiver
TUNING
dial
at
0,
c
Set
BAND
SELECTOR
to
7.0.
d
Set
PRESELECTOR
to
10
(Minimum
capacity),
ea
Set
XTAL
SELECTOR
to
2.
Adjust
trimmers
C3B
and
C3D
for
maximum
receiver
output.
Repeat
steps
1
and
2
until
no
further
in-
crease
in
output
is
noted.
Step 3
a
Set
generator
to
28.0
MC,
b.
Leave
TUNING
dial
at
0.
G
Set
PRESELECTOR
pointer
to
right
edge
of
10
M
calibration
block.
d.
Set
BAND
SELECTOR
to
28.0
MC.
e
Set
XTAL
SELECTOR
to
normal.
Adjust
L2
and
L7
(antenna
and
mixer
shunt
coils)
for
maximum
receiver
output.
6-7.
ALIGNMENT
OF
IF
TRAP.
Controls
should
be
set
as
follows:
RFGAIN
.......
10
AUDIO
GAIN.....
10
FUNCTION ...... AM
NOTCH
........
OFF
XTAL
CAL-NL...
OFF
XTAL SELECTOR . Normal
BAND SELECTOR . 7.0
TUNING ....... 7.1MC
PRESELECTOR...
Peak
on
7.1-MC
sig-
nal,
a
Connect
generator
to
antenna
input.
b,
Set
generator
frequency
to
6.4
MC
and
increase
output
level
approximately
50
DB
above
1
microvolt.

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Bottom
View
of
Receiver
Chassis.
-18-

c
Adjust
both
cores
in
Ll
(IF
Trap)
for
minimum
receiver
audio
output.
Repeat
adjust-
ments
until
no
further
decrease
in
output
is
ob-
tained,
6-8.
VFO
CALIBRATION
ALIGNMENT.
If
the
electrical
index
check
at
the
100-KC
check
points
on-all
bands
shows
that
the
calibra-
tion
marks
consistently
fall
to
one
side
of
the
pointer,
a
trimmer
adjustment
is
indicated.
(This
will
be
necessary
only
if
the
calibrationis
beyond
tuning
range
of
the
CAL
RESET
control.)
Proceed as follows:
a.
Adjust
TUNING
until
dial
is
at
500
(3.5
MC).
be
Set
BAND
SELECTOR
at
3.5,
FUNC-
TION
to
USB,
SELECTIVITY
to
2.5,
and
XTAL
CAL
to
ON,
c.
Carefully
adjust
C15F
(front
trimmer
on
top
of
three-section
gang)
in
very
small
incre-
ments
until
zero
beat
is
heard.
Care
should
be
exercised
to
make
sure
that
the
correct
100-KC
beat
note
is
tuned
in
with
the
trimmer.
da
Check
across
the
dial
at
the
100-KC
check
points.
If
the
frequency
error
is
less than
3000
CPS,
the
calibration
is
within
acceptable
limits,
If
the
error
at
the
high
frequency
end
of
the
dial
(4.0
MC)
is
greater
than
3000
CPS,
the
VFO
may
require
a
coil
adjustment
in
addition
to
the
trimmer
adjustment.
CONDITIONS
REQUIRING
COIL
AND
TRIMMER
ADJUSTMENT.
6-9.
If
the
dial
error
progressively
increasesin
the
same
direction
with
the
high
frequency
end
running
out
more
than
3000
CPS,
both
L16
and
C15F
should
be
adjusted,
a.
Tune
dial
to
1000
(4.0
MC)
and
adjust
L16
to
zero
beat.
b.
Tune
dial
to
500
(3.5
MC)
and
adjust
C15F
to
zero
beat.
eG
Repeat
steps
a
and
b
until
both3.5MC
and
4.0
MC
are
exactly
on
frequency.
qd.
Check
across
the
dial
at
the
100-KC
points.
If
the
frequency
error
is
less
than
3000
CPS,
the
calibration
is
within
acceptable
limits,
If
the
error
is in
excess
of
3000
CPS
at
any
of
the
mid-points,
with
the
end
limits
at
zero
error,
the
VFO
capacitor
should
be
knifed.
This
operation
should
not
be
attempted
by
other
than
qualified
per-
sonnel
thoroughly
familiar
with
the
technique.
-19-
NOTE
When the VFO dial is at 3.5 MC, the
VFO frequency should be 4.85 MC.
With the VFO dial set at 4.0 MC, the
VFO frequency should be 4.35 MC.
6-10. ADJUSTMENT OF FACTORY GAIN
METER CONTROL.
Controls should be set as follows:
AUDIO GAIN........5 is)
RE GAIN, 43s dcp ae’ as 10
FUNCTION ....- eee AM
SELECTIVITY ....... 2.5 KC
TUNING... 22. c eae 14.3 MC
BAND SELECTOR ..... 20 M
NOTCH ..... see .. OFF
XTALCAL-NL....... OFF
a, Connect signal generator to the an-
tenna input. Set generator output level to 50 mi-
crovolts unmodulated and tune to 14,3 MC,
b. Carefully adjust TUNING for maxi-
mum S-Meter deflection and peak PRESELEC-
TOR.
c If S-Meter does not read S9, adjust
Factory Gain control for correct reading.
d. Turn RF GAIN control to 0 and
check for electrical zero at left end of meter
scale,
e Adjust Meter Zero control as neces-
sary and repeat the above steps until the meter
reads S9 with the RF GAIN control at 10 and 0
with the RF GAIN control at 0.
6-11,
BFO
FREQUENCY
ADJUSTMENT.
The beat frequency oscillator (BFO) has
been adjusted at the factory so that its frequency
is exactly 50 KC when the BFO knob is set at 0.
A slight readjustment may be necessary occasion-
ally because of normal component aging. Todeter-
mine if adjustment is required, proceed as follows.
With the SELECTIVITY control at 5 KC,
FUNCTION at USB, XTAL CAL. at ON, and
PITCH control at 0, adjust TUNING to zero beat
at any 100-KC check point, Leaving the receiver
TUNING unchanged, switch the FUNCTION switch
to LSB. If the beat oscillator frequency iscorrect,

zero beat will be maintained in both the USB and
LSB positions. If the beat oscillator is off fre-
quency, a beat note will be heard when switching
from USB to LSB. Adjustment of the oscillator
is recommended only if the frequency of the aud-
ible beat note exceeds 200 CPS withthe BFO knob
at 0.
NOTE
In instances where the beat frequency
oscillator is considerably off fre-
quency, it may not be possible to ob-
tain a zero beat when tuning througha
signal. If this is the case, it will be
necessary to roughly set the BFO to
50 KC as follows: Set SELECTIVITY
to 0.5 KC, FUNCTION to USB, and
tune receiver to a noisy part of band
{not to a signal). Remove the BFO
knob and adjust the BFO slug for min-
imum noise. Set the SELECTIVITY
control to 5 KC and make the BFOfre-
quency check as outlined above.
If the BFOfrequency check indicates adjust-
ment is necessary, proceed as follows:
a. Remove the BFO control knob, turn
the BFO slug a few degrees in the direction that
lowers the beat note frequency, and repeat the
BFO frequency check,
be Continue varying the setting of the slug
in small steps and repeat the BFO frequency
check until zero beat is obtained in both USB and
LSB positions,
c. After the correct slug setting has been
determined, replace the BFOknob with0 inthe top
center position, being careful not to disturb the
slug setting.
6-12, NOTCH FREQUENCY AND DEPTH
ADJUSTMENTS.
Readjustment of the notch filter circuit is
not normally necessary unless the components in
the notch circuit are replaced. To check the cir-
cuit, proceed as follows:
a Check the BFO frequency as pre-
viously described so that zero beat is maintained
in either sideband position.
b. Set FUNCTION to USB, SELECTIVITY
to 2.5 KC, and tune in an unmodulated signal
(strength approximately $9} to zero beat.
ce.
Tune
NOTCH
control
for
minimum
audio
output.
d.
Adjust
notch
depth
(on
top
of
chassis,
right
side
of VFO)
for further
decrease
in audio
output.
e.
Repeat
steps
c
and
d
until
no
further
decrease
in audio
output
is noted.
At this
point,
the notch
frequency
should
indicate
50 KC.
If the notch frequency does not indicate 50
KC with the receiver at zero beat as described
above, loosen knob and reset it to 50 KC.
6-13. CRYSTAL CALIBRATOR ADJUSTMENT.
The crystal adjust trimmer is used to ad-
just the 100-KC crystal exactly to frequency by
comparison with the 10-MC signal transmitted by
Wwy.
a
Set
all
receiver
controls
for
AM
re-
ception,
set
BAND
SELECTOR
to
WWV,
and
adjust
TUNING
to
WWV
signal.
b During the period of no signal modu-
lation, turn XTAL CAL. ON and carefully set the
crystal adjust so that the crystal calibrator zero
beats with the signal received from WWV.
NOTE
If this adjustment is attempted during
periods that WWV is modulated, an
erroneous zero beat may be obtained
with the modulating frequency instead
of the desired carrier frequency.
SECTION VII
SERVICE DATA
7-1. 50.75-KC IF SYSTEM.
Figure 12 shows the type of coupling used
in the 50,75-KC IF system. Note that inductive
coupling is avoided by careful shielding of the IF
coils and signal transfer occurs only through ca-
pacitance and resistance. By increasing the value
of ''C" and decreasing ''R", the selectivity is made
-20-
sharper; by decreasing "C" and increasing "R",
the selectivity is made broader. The proper values
of "C" and "R" are switched in the circuit by
means of the SELECTIVITY control. "R" varies
the "Q" of the tuned circuit and "'C"' varies the
coupling. This R-C coupling arrangement affords
amore
accurate
means
of
selectivity
control
than
that
readily
obtainable
by
any
other
method.