TX-I
ACCESSORY
SOCKET
342
sB-to
TERMINAL6
t
6J
ANT.
RELAY
ill
ltl
RX-l
REC EI V
ER
MUTING
CON TACTS
AM-
CW
ssB
NO
T
E:
THE
RECEIVER
SHOULD
BE
I
PLACEO
IN
"STANDBY"
FOR
;
AM-CW
AND PLACED
IN
1
NR
Ec EIvE,
FoR
ssB
oPER nrroNI
L
L
--
-li
_Ji
ll
DPDr
i;
MUTTNG
ll
RELAY
ii
(see
rexr)
tl
_
cLo_s_Ep_1
TX-I ACCESSORY
CONTACTS,
EXTERNAL
ANT.
RELAY
CONTACTS,
OR
MUTING
RELAY
CONTACTS,
Figure
22
A suitable
control
circuitis
shownin
Figure
22
for
switc hing
of antenn-a
relay
and muting circuits
between
SSB and AM-CW.
The
receiverfrontpanel
muting
switch is
placed
in
STANDBY during
AM-CW
operation
and in
RECEIVE
for
SSB operation.
Thus, fuli
standby is used for
AM-CW
muting
but speaker
muting is
employed
for
SSB
duplex
operation.
An
electronic
TR switch may
be used
in
place
of the antenna relay, of course,
but the circuitry
illustrated
may still
be re-
quired
to operate
a muting relay in
some
installations.
The necessity
for
the muting relay will
depend
upon whether
or not an electronic TR switch
is used,
whether or not
the coaxial relav
has
sufficient external
contacts, and whether or not
a
"ground-when
-transm
it"
connection ntust
be
provided,
duetothegrid
block
keying
modification
of eithera
DX-
100
or
DX-
1008
transmitter.
ff
a TX-1 is used
as the companion
transmitter,
no
muting relay
will be required,
regardless
of the
type of antenna
switching device employed.
Two
methods
may be employed
to
get
on
frequency
before
actuallyplacing
the
transmitter on the
air. The transmitter plate power
must be
left
off during
these
procedures
to avoid disturbing
the
"round-table" QSO
so often encountered in SSB operationuntil
the transmitter
is on frequency
and ready for
break-in.
One
method merelyinvolves
properly
tuning in
the incoming
SSB signal
on
the receiver
ard
then
"zero-beating"
by merely
pulling
the
plug
lrom
the key
jack,
or on the
TX-l,
depressing
the
SPOTTING
pushbutton.
Once the frequency
is set, check
to make sure
the
proper
sideband
(that
of the incoming
signal) is selected
on the
SB-10
and the transmitter
is ready for
break-in.
A second
method
involves,
once again,
proper'ly
tuning
in the incoming
signat on
the
receiver,
selecting
the
proper
sideband on the
SB-10,
and then
talking
yourself
on
frequency.
This can be
done by
plugging
a set of headphones into the receiver, placing
the
SB-10 function
switch in
manual position,
and tuning the transmitter
VFO
for
normal voice
in
the receiver.
Once the
SB-10is setupin
theshackin operating
position,
it maybe necessary
toreadjust eititer
the
transmitter sensiti.vity
or receiver sensitivity controls,
due
to the change
in
position
with
regard
to the
receiver or due to
acoustic diffelences. These controls
canbe readjusted
in accord-
ance with
the
procedure
described under TESTINGAND
ADJUSTMEN
f to
suit operating conditions.
IJ
it is
desired
to increase
or decreasethetime required
for the relay
to
open
after the
cessation
of
speech
during
voX
operation, the 2.2 megohm resistor
between
F?
and FF2
can be
replaced
with
a different
value. Increasing
the resistance increases
the time
delay and decreasing
the
resistance
decreases
the time delav,
N ORMALLY
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