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.

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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.