EasyManua.ls Logo

Heathkit SB-401 - CARRIER NULL ADJUSTMENT

Heathkit SB-401
88 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Loading...
(
)
Adjust
the
slug
of
the
29.0
GRID
coil
for
maximum
indication,
]
|
HHATHEKIT
|
i
i
i
:
indication,
(
)
Readjust
the
29,0
GRID
coil
for
amaximum
indication,
(
)
Repeat
the
preceding
four
steps
until
no
further
increase
is
obtained.
(
)
Repeak
the
29.0
heterodyne
oscillator
coil
for
maximum.
|
8.6
MEGAHERTZ
TRAP
ADJUSTMENT
NOTE:
Leave
the
VTVM
RF
probe
connected
to
the
bare
_
wire
between
pins
5
of
V10
and
V11.
(
)
Remove
the
15.895
megahertz
crystal
from
the
SB-401
:
Transmitter.
Place-+the
BAND
switch
in
the
7.0
position
and
set
the
LMO
Dial\o
3.
<—
—
Place
the
FUNCTION
switch
in
the
SPOT
position.
—s~N
—_—
we
Turn
the
MODE
switch
on
the
Transmitter
to
the
CW
position.
é
Advance
the
eee
control
on
the
Transmitter
fully
clockwise.
_~
~
(
)
Set
the
DRIVER
control
fully
clockwise.
NOTE:
It
is
normal
for
the
variable
capacitor
plates
to
touch
'
the
coil
cover.
(
)
Adjust
the
variable
capacitor
on
terminal
board
#1
(see
Figure
2-2
fold-out
from
Page
93)
for
minimum
on
the
VTVM.
(
)
Replace
the
15.895
MHz
crystal.
(_)
Set
the
DRIVER
control
to
the
first
mark
above
full
counterclockwise.
)
Repeak
the
DRIVER
grid
and
plate
coils.
_~
CARRIER
NULL
ADJUSTMENT
{
)
Place
the
BAND
switch
in
the
3.5
position,
(
)
Adjust
the
DRIVER
control
for
a
maximum
indication
on
the
VT
VM,
(
)
Rotate
the
LEVEL
control
fully
counter-
clockwise,
Page
99
(
)
Place
the
FUNCTION
switch
in
the
TRAN
position,
Place
the
MODE
switch
in
the
USB
position,
Short
lug
2
of
the
MIC
connector
to
the
chassis
with
a
jumper
wire,
or
connect
a
microphone
and
press
the
push-to-talk
button,
(
)
Adjust
the
CARRIER
NULL
control
and
ca-
pacitor
for
a
minimum
indication
on
the
VTVM,
(
)
Place
the
MODE
switch
in
the
LSB
position
and
adjust
the
CARRIER
NULL
capacitor
to
the
same
VTVM
reading
obtained
in
the
USB
position,
(
)
Place
the
MODE
switch
in
the
USB
position
and
adjust
the
CARRIER
NULL
control
fora
minimum
indication
on
the
VTVM,
Place
the
MODE
switch
in
the
LSB
position
and
adjust
the
CARRIER
NULL
capacitor
to
the
same
VTVM
reading
obtained
in
the
previous
step,
_~
—
(
)
Repeat
the
previous
two
steps
until
the
same
VTVM
reading
is
obtained
in
the
USB
and
LSB
positions
of
the
MODE
switch,
NOTE:
The
preceding
five
adjustments
can
be
checked
after
the
Transmitter
is
in
the
cabinet
by
using
a
receiver
set
to
the
operating
fre-
quency
and
observing
the
''S"
meter
for
minimum
readings
as
the
adjustments
are
made,
(
)
Return
the
FUNCTION
switch
to
STBY.
( )
Place
the
MODE
switch
in
the
CW
posi-
tion,
(
)
Disconnect
the
RF
probe
of
the
VTVM.
\
NEUTRALIZING
(
)
Rotate
the
BAND
switch
to
28,5,
(
)
Place
the
VTVM
RF
probe
inthe
ANTENNA
connector,
(
)
Set
the
FUNCTION
switch
to
TRAN,
(_
)
Rotate
the
LEVEL
control
fully
clockwise,
(
)
Key
the
transmitter,

Related product manuals