'.
5,
OPERATIO~
5.1
Bci,)rc
attcmring
to
orerate
the
rccei\"a.
the
information contained in this section should be
thoroughly
understood
by
the
operator.
Tn<!
symhols
on
panel u5cd
to
desIgnate
the
various
controls
as
shu\vn in Figure
1,
should be learned
with respect
to
function, as described
h~r~in.
5.2 The-
Antenna
T
rimmer:-
The
center
knob
on
the left is
the
Antenna. Trimmer. Before tuning
on
any
frequenc)' range, it should
be
adjusted
for maximum performance on
the
band.
This
control
may
be
adjusted
-by
tuning
for
maximum
background
noise.
Occasionally
it
is desired
to
test
a.
signal
that
seems
out
of
place, to see
whether
or
not
it
is
a
fundamental signal
or
an
..image
....
Wlfen
doing
this, if
the
maximum signal
point
coincides v·:ith
the
point
of
maximum
background
noise,
the
signal is a fundamental.
If
the
control
doe,
not
affect
the
signal strength,
or
if
it
is
'a maximum
at some
other
point, it
is
an
"image",
5.3
The
Main
Tuning
Dial
is
on
the
left and con-
sists
of
Cl
disc
with
SC\'en
scales, one for
eac~
of
the
six
bands
and
a log scale.
The
twe
lo\\' fre·
quenc)'
bands
are calibrated in kilocycles
and
the
other
four
bands in megacycles.
5.4
The
Vernier
Tuning
Dial is
in
the
center
and
has a scale
with
arbitrary
calibrations
for
exact
tuning
and
log records
of
particular
communica-
tion stations.
It
is used
in'
COn
junction
with
the
log scale on
the
main
tuning
dial to give addi·
tional figures
for
logging.
5.5 Power-
Transmit-Receiver
Switch:
-
This
is
a
four-positiop switch:
Starting
from fully coun·
ten:lockwise these positions are:
1.
Power
off.
~
Transmit
position
which
gives energi:.ecl
tube
filaments,.
open
plate
circuits, and
shorted
terminals
(for
transmitter
relay)
on
the
speaker
terminal
board
on
the
back
of
the
chassis. (3.
fi
4.
on
T.B.·Z.).
Connect
rday
to
these two terminals for transmitter
operation. (See Figure 3.)
.
'.
Normal
reception.
4.
CW
reception -Beat
frequency
oscillator
switched
on.
5.6 Selectivity
Switch:
-
This
is
a five-posinon
switch and
the
band
widths
and
control
of
selectivity are illustrated in
the
curves
of
Fi:;urc
11.
The
five positions are:
1.
I·F
band
width
for
High
Fidelity, modu·
lated reception, -
for
"Stand·by"
use.
o
I.F
band
width
for
normal
modul"teJ
reception.
>.
Crystal
Filter in -for
CW
telegraph
or
sharp
modulated signal reception.
'
..
[8}
Cryst..d Filter
in
- -
for
!-harf'Lr
CV".,
tele-
graph
reception.
...
Crystal
Filta
in -for snarr\:.5t
C\V
tele·
graph
reception.
5.7 Noise
Limiter-A
VC
Switch:-
This
is
a four·
position switch
and
starti~g
from
the
fullr
counterclockwise- position thc.x: are:
1.
A
VC
and
NL
out
_.
Manual
gain only -
for
CW
-
n'o
interference.
o
NL
on, A
VC
out
-
Manual
gain -for
CW
\vith interference.
,.
Nt;. and A
VC
on
-for
Modulated
Recep'
tion
with
interference.
4.
A
VC
on,
NL
out
--
for
ModulateJ
Re<ep·
ticn
-no interference.
S.B
RaF
Gain
Control:-
This
continuously variable
sensitivity control is
for
use.in conjunction
with
the
audio
gain
(Volume)
control for all manual
gain operation.
With
A
VC
on, it
should
as a
rull!
be
set to its fully clockwise position
or
may
ht::
turned
to
eliminate interfercn;:c-.
For
re..:ep-
tio!1
of
strong
CW
signCils,
it
mu::
he
retarded
somewhat.
5.9 Noise Limiter
Control:-
This
control sets
the
instrument
for
operation
at
the
required per-
centage
~'alue
of
Noise
Limitation.
The
fully
clockwise position limits
the
noise
interference
to
1007c modulation.
As
the
knob
is
turned
counterclockwise,
the
noise interference is
lim~
ited to continuously lower percentages
of
modu#
lation so
that
in
the
fully counterdock\.
....
-ise
posi#
tion
the
Noise Limiter
is
operati\.·c
on
ani'
modulation \vhatsoever. Normally.
the
fully
clockwise position will be used,
rut
under
ex"
treme conditions
of
interference
a t-alance point
should
be
found
for
maximum inte!lig:ibilitv
of
signal
with
best modulation
and
lel~t
~oise.
~
5.10
Tone
Control:-This
is a continuously variable
control for reducing
HF
response.
In
the
fully
clo.:kwise position
the
fulI
tonc
is
obtained
and
as
turned
counterdoch,-ise.
high tones arl!
lessened. Set
it
to
suit
the
particular tona.l con·
ditions
for
the
signal
being
received.
5.11 Beat Frequency Oscillator
Control:-
This
con'
trol
is
normally used for
C\V
code signals.
It
should
be
adjusted
to
give
the
desired audio
pitch
after
the signal has heen accurately tuned.
5.12
Tuning:-For
functions
of
controls sce
the
foregoing paragraphs.
1.
Turn
receh-er
on
and
set
the
Powcr#
Transmit·Receive
Switch for
the
requireJ
type
of
operation.
1.
Set
Range
Switch
for
band
required.
3.
Set
Antenna
Trimmer
for
maximum back-
ground
noise.
"
•
•
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•
