Heathkit SB-401 Assembly Manual page 157

The output signal from tube V5 is coupled to
drive V9 through capacitor C302. AnyRF energy
that may be fed through the bandpass filter at
approximately 8.6 megahertz present at the plate
of V5, is passed to ground by a trap, consisting
of RFC2 and capacitor C303.
are passed to ground. In this instance, the dif-
ference between the sideband frequency of 8.5
megahertz and the heterodyne oscillator fre-
quency of 12.395 megahertz results in a heter-
odyne mixer output frequency of 3.895 mega-
hertz.
:)
~
z
z Z
...J
W
a:
a:
a:
en
>-
IX)
RED
o
o
BlK
3.5
0
0
•
0
0
,.....
•
•
0
~
cO
•
•
~
C\I C\I
-
C\I
83F
-
C3
__.__
Io05
0
0
0
0
C56
0
C55
0
~
0
CI')
,.._
C54
C53
,.._
C52
t')
"It
•
~
50
'\I
62
....
100
0.
100
co
270
PF
Cf\
PF
t'f) (\I '\I
ct
Q:
PF
Q:
PF
ct PF
DRIVER GRID COILS
C51
Toos
-
Figure 6-11
TO KEYED 81AS
-
-
-
-
- -
I
I
I I
/ I
/ _I -
L_-'- __
.01
22PF" 3-12
PF
8.6MHZ
TRAP
_ AD,,).
150PF
C212 1/209 C2 13
-
33K --
IOOPF
r---f ~ ~__.
TO
DRIVER
83R
-
RFC2
30
UH
C302
....
-
-
--
-
-----
V5
6EW6
HET. MIXER
Page 133
R206
47K
FROM
HET.
R207
OSC.
C211
220K
.02
FROM
BANDPASS
COUPLtR ...... .....-~ ~ .....