Heathkit SB-10 - Operation

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BA
I
WANTED
(/*olo
t N
U NWANTED
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SUPPRESSION
IN
DB
20
25
30
?q
40
A+B
(A_
BT
to
t8
32
56
loo
Figure
21
(
)
Connect
the audio
output
of the
receiver
to
terminals
1
and
2
on the
rear
of the
SB-10
and
the
receiver
speaker to terminals
2 and
3.
Make sure that
if one side ofthe
receiver
audio
output
is
grounded,
that this
lead
is connected
to terminal
2 on the
SB-10.
(
)
Tune in
a fairly
strong
signal
on
the
receiver
and adjust
the
receiver
gain
for normal
operating
volume.
(
)
place
th; SB-10
function
switch
in VOX
position.
Do not
turn
on
the transmitter
plate
porver.
with the transmitter
sensitivity
tontrol
in the
same
position
as
previously
set,
hold the
microphone
about
3 Ieet
in
froni
of
the
receiver
speaker
or
close
enough
to
start
the vox
circuii
cycling.
N9w advance
the
receiver
sensitivity
-until
the
cycling
ceases'
This
adjusts
the anti_tiip
actionior
normal
operation.
Recheck
for
normal
voice
operation
and
readiust
the
transmitter
sensitivity,
if
necessary'
(
)
Turn
off
all
power
and
disconnect
all
cables
and
wires
froln the
adapter.
(
)
place
the
plastic
control
guards
on the
phase
and balance
controls.
(
)
Insert the
four
small
rubber
leet
in
the
four
holes
in the bottom
of the cabinet.
(
)
Place the
adapter
in
the cabinet
and
secure
with two
+6
sheet metal
screws
through
the
back
panel
into the
two
corresponding
holes
in the
rear apron
ol the
chassis'
(
)
Place the adhesive
label on
the back
of
the
cabinet
above
the
opening
for the
rear
chassis
apron'
This completes
testing
and
adjustment
of the
SB-10
SSB Adaptel"
OPERATION
For
on-the-air
operation,
the
SB-10
connections
are the
same as
described
under
Testing
and
Adjustment. Tuning
and operatingthe
transmitter
and adapter
is
accomplished
in the
same
man-
nei as
used duringlnitial
testing.
OnIy
one
word
of
caution
to the
newcomer
to SSB:
Use
audio
gain
sparingly
to
prevent splatter
due
to
flat-topping.
In
general,
Iower sideband
(LSB)
is used
by
most
amateurs on
the
80 and 40 meter
bands
while
the"upper
iidetantt
(USB)
isusedon20,
15 and
10
meters.
position
on
the
SB-10
mode
switch
produces
a double sideband
signal.
Carrier
maybe inserted
in
any mode
(USB
and carrier,
LSB and carrier,
or
DSB
and carrier)
by merely
rotating
either. carrier
null
control
from
the
balanced
position.
The resulting
signals
are
aII
AM
with the latter
(DSB
and carrier)
being
simi-
1ar to a normal
high
levet
amplitude
modulated
carrier.
However,
when inserting
carrier,
be
sure not
to exceed
the average
plate
dissipation
of
the final
amplifier
tubes.
Thus, if
carrier
is
inserted,
the
finai
amplifiei
sirould
only
be
loaded
to 100
watts input
(125
ma).
If considerable
AM operation
is at
times
desired,
then
a simple
return
to the
normal high
level capability
of
ttle
"o*pi1ion
transmitter
is
the logical
choice,
for
the obvious
reasons
of
increased
efficienCy
and
effectiveness.
The terminal
strip
on the
rear
of the
SB-10
provides
a capability
for
antenna
relay
operation,
exciter
keying,
and
receiver
speaker
muting
as
indicated on the
rear apron
label.
Receiver
speater
muti.ig
during
SSB operition
is
generally
preferredto
placingthe
receiver
in STANDBY.
\iith modern Joaxial
ielays
and
electronic
TR
switches,
adequate
protection
against
damage
to
the
receiver
RF stages
due to overloading
is
afforded.
Page
56