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1e frequency
modulated
146
to
148
MHz signal
is amplified
by Q210,
:c741,
Q211, 2SC730
and
Q212, MRF212
and
applied through
a two
age pi-network to the
antenna.
A
diode D204,
1Sl88FM
rectifies
s
mall
portion of
the RF
output and applies the
resultant
DC voltage
the
meter
where
is
provides
an indication of
relati
ve
power output
om the
transmitter.
The
meter
sensitivity is
adjusted
by
VR204
Ld
it is
set for
indication
of 8 on the
meter
scale
a
t l O watts on
a
l
ohm r esistive load.
the transmitter is keyed without
an
antenna
connec
t
ed,
or ifa high
\T'R
exists in the
antenna
system
,
the
reflected
power is
detected
rough
T210 and
a diode D207,
1Sl88FM
produces
DC
voltage.
~15,
2SC372Y conducts with the DC voltage applied
through
VR209
.uaing Q216,
2SC3
72Y to decrease
its
collector current. Thus
,
e
emitter
voltage of
Q217
,
2SA496(0)
is lowered
causing
Ql,
:D313
to
decrease
current
and the supply voltage to the
PA
amplifier
nz
is
lowered
to prevent
damage of
the transistor.
The
protection
vel is
set by VR209.
This
circuit is
also used to
switch
the output
·
w er down to
l
watt where the
ID/LOW
switch is s
et
to LOW position.
1e
amount
of power
reduction
may be
adjusted by
VR208.
1e
antenna
change -over circuì t consista of the switching
diodes
~05
and D206,
Ml
301.
~CEIVER
SECTION
te 146
to 148
MHz input signal from the antenna
is
amplified by
~T
QlOl, 3SK40Mon RF board,
and
applied
through five
hi-Q
)t-coupl
ed
resonators
to
the
first mixer,
Q102,
3SK40M
.
...
di
Q,
Q
Q
,
a
..
X,
a ..
Q,
Q,
Q
Figure
8
Top View
14
-
~
l
·t
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