APPLICATIONS
TRANSCEIVER THEORY & TROUBLESHOOTING
INTRODUCTION
CB
Transceiven differ greatJy (rom model to modeL
Some
may use tubes,
transiston,
or
Ie.
while
nthen
an!
hybrids made up
of
more
than onl!
type
of
active
c:omponenk.
MOlt
uanaeeiven.
hOW_f,
follow
standard
block
diapms.
8y
tWdyini
the block
diagrams
for
various
typet;
ot
U'ansmitter and re<:riwr ll!Cti.oov,
it
ill easier
to
int<!rpn!t
the
manur..ctu~·
•
.mem.lie
diacrams.
The
followin,
block diagrams
mver
the mO$t
COOl·
mon types
of
CB transceivert. ElIch diagram
abo
eontains
notel
lU
to
the
type
of
lroubleshooting tech.
nlqucs-signal
injedion
or
sign.l
tracing-that
may
be
AM TRANSWTTER
II5l!d
with
the CB42 CB Analyz.er.
The
CB42 il equipped
10
inject
IoignalJ
into
any
stage-
from
thl!
.ntenna
input
10
the
speaker
ot.
receiver,
or
(rom
the
microphQl1e
to
the
antenNl
output
of
I
transmitter.
Whm
tued
tor
signal tracilll,
the
m-
quency countet' becomes a valuable
tool.
A
~
uacing
aid ill •
higb-.enJitl'lity
..
olt
meteor IUcft u
the
Seneore DV,",38
\lied
1rith
•
RF
probll!
AIm
as the
8ftIeore
3903.
The
hlock
diqrams
OOVi!r
AM
U1mlmitten and
receivers, and
then
SSB transmitters and receivers.
--.
"
-
TVl Filter
t
.......
RF
Pa_,
Mod
......
lion
"0"
dIInnel
"......,
use
__
PI"
FiB.
14-TypictJl
AM
trommitter.
An
AM
transmitter
requirft
two lignals to provide
the
amplitude modulall!d
output
u..,t
..
fed
to
the
an-
tenna.
The
tint
..
an
Rio'
lienal
operatinlJ U tile CB
dlannel
frequency. FCC RlIet
require
that
this
ligna!
must
be
supplied
by
.. crysW
conlro~
otciIWor.
'The
RF
arner
must
be
within
.OO5'i1o
of
the IpeCified
channel frequency.
Thill
RF
signal is
amplifled.od
fed
to
...
\.8ie
or
set
of
ltages
that
can
be
modulated. One
common
method
or
providing
thil
modulation
II
to
take.the
output
of
AM
RECEIVER
The~
are
two
balic types
of
AM
receiYl!'n in general
ute.
Lowt't
priced recei¥en 11M!
.~
rollVltrsWn
'0
the
audio amplifier and feed
it
to
the
oollecton
of
the
RF amplifier tr1lIlaiston.
The
bias
on
the
coIJecton
now
chan
...
in
~
with
the
audio
aignal wbile
the
RF lignal is applied
to
the
hue
of
the
dri~r
cnnsistor.
'The
rPSLIlt
is amplitude
modulation
of
the
RF
carrier.
Filtering
rtaees
(TV!
filten)
_ ..:Ided
.t
the
output
of
the
RF
amplifier
to
eliminate
lUly
Iw'monic
oon-
tent
which
would
CllUIe
interference
in
other
com-
munications bands.
auperheuodyne
receiven.
In
this receiver.
the
incom·
ing
RF
aiplal is
mind
with
the AgnaI
of
• local oacil-
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