Operating instructions
Ai
+r.5
v
Dc
Bf
+90
v
Dc
s tol
sEcr.4
/
REAR
\
sro3
ì'sEcT. 2
Section
I l.
51.
Block
Diogrom
(fig.
23)
n.
Radio
Receiver
R-174IURR
is
a
portable
receiver
operating
over
a
frequency
range
of
1.ó
mc
to 18
mc.
Either
a-m
or
c-w
signals
nrril'
be
received.
The
signal
path
is
shown
in
rìgule
23.
Ò.
The
signal
voltage
induced
in
the
antenna
:.
iimpiified
by
r-f
anrplifler
stages
V1
and
\r2
!',,nnectecl
in
cascade,
and the
amplified
signal
.-
ioupled
into
converter
tube
VB.
The
antenna,
:
atr-rpÌifier,
and
converter
inpnt
circuits
are
'
rìf(l
manLìally
to the
radio-frequency
signal.
.
l,,call1.
generated
signal,
u'hich
tracks
4bb
rrbove
the
received
signal,
is mixed
elec-
::ically
with
the incoming
signal
in
the con-
R ro8
roo
NOTES:
I.
UNLESS
OTHERWISE
INDICATEDI
ALL
RESISTANCE
VALUES
ARE
IN
OHMS.
2. SWITCH
SECTIONS
DESIGNATED
NO.
I
ARE
NEAREST
THE
KNOB
END.
3.
CONTACTS
OF KIOI
NORMALLY
CLOSED.
4.
qwllgl!_sEcl0NS,
AS
vtEWED,
ROTATE
c0uNTERcLocK
wlSE.
+
t.4v Dc
FILAMENT
VOLTAGE
TESÎ
POINT
J
3LO"),\
REAR
I
powrn
I
lselrcron
I
Figure
22. Pott'er
Supply PP-S08lLf
RR,
clry-batterg
operation,
ftmctíonal
sch3m(ttic.
RADTO
RECETVER
R-t74lURR
verter
stage.
The
output
of
converter
tube
VB
is
tuned
to
the
difference
frequency (4Sb
kc),
and
this
signal
is
supplied
to
the first
i-f
ampli-
fier
tube,
V4.
c.
The
455-kc
i-f
signal
is
amplified
succes_
sively
in the
first
and
second
i-f
stages,
V4
ancl
V5 respectively.
The
i-f
output
of Vb
i-q fecl
to
the
diode
section
of
tube
V6.
d.
The
diode
section
of
V6
rectifies
the i-f
signal,
and
a detected
audio
signal
is
conpìccl
t.o
the
pentode
section
of
V6.
Auclio
aniltlifìt,atiotr
is
provided
by
the
pentode
section
of
\-li
:rncl
b1'
either
Y7
or
V8. The
output
of
ejther' \-7
or'
\'g
is
supplied
through
OUTPUT
HICIH-LO\V
switch
54 to
the PIIONtrS
connector.s
at-rrl
the
loudspeaker
in
Pou'ei'
SLrppì1- PP-308
URR.
rM
295-23
37