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50 MHz UNIT
The 50 MH z signal from the antenna is fe d thro ugh
a lo w-pa ss filter, con si sting of C323 , C 324 , L312,
an d L313 , to RL301. On receive, the signal i s ampli
an d fed thro ugh a selective
fie d by Q20 s
(3SK51)
ban dpa ss filt er, which is t une d to the operating
fre quency by varactor dio de s D 210 an d D211
The secon d gate of Q1os is connecte d
(1S2209).
through a large re si stor to the front panel RF
GAIN control, allo wing variation in the gain
of the RF amplifier.
The signal i s then fe d to the mixer, Q106
where the 50 -5 4 MH z signal i s mixe d with a local
signal of 2 2 or 24 MH z, pro ducing an IF signal of
28 - 30 MH z which i s fe d through a diode s witch to
the 10 M OUTPUT jack.
The local signal i s generate d by cry stal o scillator
an d
Q 207
(2SC784R),
For repeater operation, th e local
(2SC784R).
signal i s shift ed up or do wn 1 MHz, according to
the position of the front panel R PT switch.
For tran smi ssion, the 28- 30 MH z outp ut signal
from the tran sceiv er i s fe d to the balanc e d mixer,
I 6 M U N IT (P B-=1 9 2 2 , 19 2 3)
I
I
I
I
ALC ANPo--- - ---
1
IOm
INf>lJT
I
I
I
I
1
I
I
I
I
I
I
I
�---
IOm
OU1PUT
1
I
L-----------�------------------�
,
(3SK51 )
amplifie d
by
Q1o s
-
-
----------
--
--
--
Q201
Q202
B PF
MCl496G
35K51
MIX
AMP
02oe
0207
r
25
c784R
25c7e4R
- - _
05 C
8
I
50-52MHz
22MHz
I
52-54MHz
24MU
I
2 I MHz
50-
I
52MHz
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23MHz
I
52-54MHz
I
I
��
I
B p F
35
RF AMP
Q 101
(MC1496G),
signal delivere d from Q208. The 50 - 5 4 M H z signal
is then pa sse d thro ugh a selectiv e ban dpa ss fil ter,
which effectively eliminate s sp urio us signal s. Th e
signal i s then amplifie d by the amplifier chain,
consi sting of Q102
Q10 4
(2SC730)
The
(2SC19450).
mately 10 watt s i s th en fe d, via a lo w pa ss filter, to
the ANT jack.
A portion of the o utp ut from Q301 i s det ecte d by
D303 an d D30 4
( 1Sl555),
voltage i s amplifie d by Q111
p urpo se s. A portion of the outp ut from L311 i s
detecte d by D3o6 an d fe d to the ba se o f Q111,
controlling the bia s of Q111 an d Q302 . Q11 o
work s a s a switch f or the automatic
(2SC1815Y)
final protection circ uit, which will red uce the gain
of the amplifier tran si stor s in ca se of high SWR.
A f urther portion of the outp ut i s detecte d by
D3os
an d fe d to the meter, for an
(1Sl555)
in dication of relative po wer o utp ut.
Q3o9
reg ulate s the supply voltage at 8
(78L08)
volt s for the tran si stor s.
----
-----------
0203
25C2053
AMP
I
C
- 14 -
where it i s mixe d with the local
Q103
(3SK51),
(2SC2053),
QJ01
(2SC2166),
an d
o utp ut
signal
of
approxi
an d the re sul ting DC
for ALC
(2SC1815Y)
-,
-
-
I
I
I
Q302
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