nal antennas should
coaxial cable,
motive
most radio
MOBILE INSTALLATION
having
receive police
of this
ization
he responsible
for
fair-to-good
may
If
an outside
l55mHz
H bands or a 460mHz antenna on U band only.
and
type
receiver
This
VOLT
a 12
[n
some areas it is illegal for
radio
through local
Place
l.
hold
is
shipped
mobile
dealers.
is responsible for
or table use.
signal strength,
be used
antenna is necessary
antenna on all bands, a 40mHz antenna
be coupled to the receiver by 50
as RG-58 A/U,
such
connector.
may
be installed in
NEGATIVE
communications
agencies and Electra Company
for
any illegal
mobile
the
the receiver in
complete
As a fixed
the telescoping
on all bands.
Suitable antennas
GROUND
on
a mobile receiver.
obtaining
installation
mounting
the desired position.
for fringe
using
any car,
unauthorized
bracket under.the
with
the necessary
receiver
the
are available
truck,
SYSTEM.
necessary
any
usage.
or
ac-
in areas
whip
antenna
reception, you
for
Exter-
ohm
supplied
auto-
boat, etc.,
persons
user
The
author-
cannot
dash
to
to
The BC-4 has
squelch system.
electrical
system and other
problem, particularly
ject
of noise elimination
ly in
this instruction
It is
recommended for
with the
book" or
subject to
"The
Radio Relay
at
It is further
vice center which
communications equipment for
high noise immunity
However,
in
areas of
is
the noise
parts
low
lengthy
too
of
book.
those who
purchase
"The
Mobile Manual" published
l,eague and
recommended
specializes
by most electronic
sold
that the vehicle
VHF-UHF
in
correction
because
generated
car
the
signal
strength. The
to deal with
wish
to become
Radio
Amateur's Hand-
by
be taken
of a noise
of the noise
by the
is
sometimes a
auto
sub-
adequate-
familiar
American
the
parts
stores.
to a ser-
two way radio
problem.
OPE RATI ON
Mth the power cable and antenna properly connected,
l.
turn the receiver
by rotating
ON
"VO[,UME"
the
control clockwise.
3.
Place
the B channel switches in the up
Set
Adjust
rushing
control
"MANUAL-SCAN"
the
"SQUELCH"
the
noise
heard.
is
counterclockwise until
Then
switch on
control clockwise until
adjust the
the
(ON) position.
"MANUA[,".
"SQUE[,CH"
the
rushing noise dis-
apPears.
Mark
and drill
secure
the bracket with
screws.
Insert
3.
4.
5.
the two
inward,
secure the receiver
and
two ll4" lD x
Attach
"acccssory"
External
above.
extended for
approximately
holes
two
plastic
in
the desired pair
in place
9l16"
DC
the
mobile
The autornotive
power
"radio"
or
antennas may
L
H bands. It
or
lB" for U bands.
using
a 7164 drill
the two
"T"
OD flat washers.
cable
terminal
antenna
No.
washers,
mounting holes
of
with
the twoIl4-20bolts
and connect
on
the
used
be
may
should be reduced
bit and
6 self-tapping
flanges
turned
and
it
to the
fuse
block.
as described
be used fully
to
-3-
Press
5.
continue
should
the
to quiet
TWEEN
The
6.
to
7.
To
UAL-SCAN"
be omitted
switch
"MANUA[,-SCAN"
the
to step through all
"break
the squelch" on any channel,
switch
channels. If
squelch control counterclockwise
the receiver. THIS MUST
STATION TRANSMISSIONS.
"MANUAL-SCAN"
select and monitor
sample
channels
all
switch to
as desired by moving
switch
any desired cl"rannel.
automatically, return
"SCAN".
may now
the individual channel
downward ("f0.
downward and
noise
the
adjust
again slightly
DONE
BE
the
be
"MAN-
BE-
used
Any channel may
Page 4
CRYSTAT
DISCONNECT
LEAVE POWER
remove
To
tom rear
inet. The components
easily
of
corresponding to its channel.
the
band for each
a particular channel,
position.
position
the third or
mHz)
edge.
accessible.
Up
to
L, H,
or
radio)
The
of the
andooT"
POWER BEFORE
WHILE
OFF
cabinet, first
the
Push
eight crystals may
U/T
bands. Each crystal is installed
eight
three-position
crystal.
(Nearest the
switch selects
o'U/T"
(470-5l2mHz)
rear panel forward
the
and
To
place
the corresponding
front
position
INSTALLATION
REMOVING
INSTALLING
remove
crystal
installed
be
(Channel I is nearest
slide
select
of the radio).
"Hi"
used for
is
bands.
the screw at the bot-
through
sockets are in
in any combination
switches select the desired
"Lo"
Band
(30-50mHz)
switch
The
Band (150-l74mHz) and
both
CABINET
CRYSTALS
cab-
the
full
in the sockets
center
"U"
and
view
the side
in the
"H"
or
(450-470
for
"L"
,,UIT"
Received
frequency - 10.80 mHz =cr1 stal
frequency
I
Example: 453.250
mHz - 10.80 mHz = {9.16llI
mHz
9
USER
man-made
lines, fluorescent
of
etc.
such
of
this
conditions
prevents
channel
HINTS
Radio
equipment
electro-magnetic
lights, motors, appliances,
Modern radios
sources
unusually
Distant
weak,
receiver because of
interrupt
reception
may
are
but
operation
noise.
strong
".hp"
be bypassed
usually
noise which
designed
may be affected
noise
or
high
its
scanning
of other
by
environment
operates
in an
radiates from power
ignition systems,
to minimize
interference
under conditions
may be
signals
sensitiuity.
whenever a
or
Whenever
very
desired signals, the
means
its individual
of
from
received by
such
channel
busy
affected
panel
of
switch.
00 0000 00
t23.1
5878
[il[[[[00
Remove
by
stal
aligning the pins with
down. DO NOT BEND
TURE
WILL
crystals
CRYSTAL FORMULAS
SOCKETS
BREAK OFF
NOTE: Do not
Rigid
by Electra Company
warranty does
from
The
"H"
150mHz to
frequencies
New
'(L'r
"H"
-
crystal by a
the
ARE N,IADE
IF
BENT
install
two crystals
qualiry'
"U/T"
Received
Example:
Received frequency
Example:
standards are applied to crystals furnished
to assure full performance.
not include
other
sources.
alignment
l7[mHz,
may be
frequency
35.80
155.01 mHz
mHz
pull
gentle
the
upward.
sockets and pushing
THE SOCKETS.
OF SPRING
EXCESSIVELY.
of the
correcting
spread is 450mHz
and the
added within
+
10.80
-
3
poor operation caused
"L"
these
mHz = crystal frequency
+
f0.80 mHz
10.80 mHz
-
10.80 mHz
=
=
crystal
3
Insert
the cry-
straight
THESE \'IINIA-
BRONZE
same
therefore our
to ll2mH.z,
33m[z
spreads.
46.600fi) mHz
frequency
=
48.07000
AND
frequency.
to ABmHz.
by
the
ln cases of strong
desirable to
pickup
medium
reduce
below a
and
strong signal
-Single-channel operation
under Operating
with
ing
will
"\IANUAL-SCAN"
the
all but
out
alwavs be
the
on that channel
Continuous-carrier
interfering noise
length of the antenna to
the
critical level.
This
or signals
may be very
areas.
may
be obtained as
Instructions. It may
in either
switch
also
be
position
desired channel. This assures that the
signals
even when
as
such
turned
ESSA weather broad-
the
casls on 162.55mH2, which are available in many areas,
be received when desired by use of
swi
tches.
In mobile
tion conditions
systems,
setting of the
Shen
power
squelch
moring
service the
are signal
lines
or shipping
antenna to avoid damage
commonly encountered
fading, nearhy faulty ignition
proximity
and
control
will minimize these conditions.
the radio, remove
it or to the internal circuit assem-
to
individual channel
the
to strong signals.
the
blies.
RADIO
Locd Govemment
Highway Maintenance
Forestry-Conserration
Motion
Special
Telephone Maintenance
Automotile Emergency Power
Public
Mobile Telephones Forest Products
SERVICES
Pictures
Indusbial
Mobile
Radio
Emergency Police
Specid
-Hospitds
-Ambulances
-Physicians
-Disaster
-School
Peholeum
Relief
Busses Taxicab
Fire
Press
Business
Railroad
Marine
Manufachrers
Motor
Rural Radio
-4-
it may be
noise
reduce
effective
in
described
accomplished
lock-
by
radio
OFF and ON.
may
poor recep-
Careful
telescoping
Carrier
Page 5
ALIGNMENT
I-F
SECTION
Nignment
and balancing
of
the detector
by quartz crystal
tivity.
Field
alignment
l. Connect
2.
3.
4. Detune
5.
I-F
the
filters
and
should not be
Connect
Maintain
prevent
to
T5
Adjust
T3
Adjust T5
for
and
best
system
output. The
"peaking"
consists
necessary
EOUIPMENT
Sweep
generator with 10.79,
and l0.BlmHz
generator
sweep
oscilloscope
output of
distortion
for
for
so
linearity.
lo.
10.B0mHz
from
maximum
maximum output,
that 10.80
8
of
optimizing the input
bandpass and center frequency
the coils can
but the procedure
result
in bandpass ripple or
is
NEEDED
Oscilloscope
10.80
markers
to TP-l through a lpf capacitator.
to TP-3.
generator
sweep
overloading.
IF output display.
mHz is in
Figure 3.
See
and T4
center
at a low level
See
for
minimum ripple.
of discriminator
and output networks
for
given
Figure
general information.
2.
curve
established
are
poor
sensi-
ALTERNATE
Model 800
+
25kc. Markers
The R-F
disturbed.
Factory
test modules,
unique
The
maximum
performance
DESTROYED
Figure 2
METIIOD:
Generator
D() NC)T
are
or
not
essential
ATTEMFT
alignment points
alignment involves
output
indicators
R-F
system inclurles
over a
BY
AN
ATTEMPT TO
to.8l
I-F
alignment may be checked
equivalent
since center frequency
R-F
ALIGNMENT
are adjusted
and training
electronic
wide range
"PEAK
tuned
to an operating frequency
SECTION
"PEAKNG''
OR
and
sealed at the
multi-frequency
beyond
the scope of normal
tracking
frequencies.
of
UP''
"TWEAK''
OR
Figure 3
using a Measurements
and swept
is determined
OF R-F
SECTTON.
factory
by the filter.
and
should
not
be
signal generation systems, add-on
service
of R-F
and oscillator
THIS PERFORMANCE
"OPTIMIZE'"
OR
activities.
circuits for
CAN BE
ETC.
-5-
Page 6
l'4A
33o
49
R
470
c42
.ool
c4/
.ol
a
.|
c2
3.3
Rt6
loK
Rls
33K
D4
ct8
;.;
Rzz
O
R3
33K
*re(c)
"l
t
loo
R5
Z.ZK
R19 5
27Kf
.'i-44
f
R24
loK
+t2 (c)
RzO
56K
DGT
t
f
T
\?.,
ci3
Lrot
czs
.ol
,x,,h^vvc3
=
I
331
Ln +
f
c24 t
47O
vvcs
V22 tll-3
'.'ru
L
R27
22K
I
+tZ
3
c4
.o0
{
O
R56
R57
loK
R55
47K
(C)
+12
RESTSTOR
CAPACITOR
U1{LE33
CRYSTALS
ll-18
sw
VALUES
Y
OTIIERUI9E
Y-I TO Y-8
OHng
ft{
LIIESBELOU
^bvE-
ABovE
SPECIFIED
vll
H
L
I Iil
I lN
R4l
330
c36
.ool
TFD
pl
c
R42
22K
+12
+12
(c)
Ll4
c32
470
R38
33K
R37
loo
| css
* ro
DB
+ toK
C59
.oot
c37
.ool
BEARCAT
rT\
+
T'
€
*
,1u
R54
47K
N
c40
1-
J-
=
R50
K
6.8
R53
4.7 K
SCH
R48
6.8K
R52
loK
|
I
I
!
Page 7
c55
R74
IM
sw3
R65
loK
c56
ool
c 45
.oo 5
Ll5
ll-l-Ilr
-E--=:-:r
. OOI
470K
R75
IM
R88
470
FLI
R66
'oo
FLz
.otuot
FL3
S
Ll6
139
+
c
Dlo
47l
.l
R78
820
c54
.l
+12
c48
.l
R76
IK
*lz
I
c57
.o47
9
tc-
t35
R77
loK
+12
cso
0l
.05
f
?
R79
47K
Ll7
c52
c49
470
cs3
.l
c5l
3.3
T
*
ttu
R80
toK
VOL.
c58
z.zut
.oo33
+
R8l
33K
R,69
loK
c60
l2
toK
c59^
.ol
82
+
13
c6l
IOO MF
6V
Io
+
R86
to
R97
470
R96
22
I
R72
39n_
+
c62
IOOMF
K
R7l
+12
33
c64
too
c
65
.01
R99
56
+12
R84
K
1.5
SQUELCH
R87
5K
K
x'93*
R98
47K
ilo2
t?o
RtoT
2.2M
I
I
4l
t70
Yl AT IC
T6
c69
.05
RtoS
47
0 l/2w
R
tlo
3.3
20h
Rill
5.3
2"h
K
K
+12
A.C.
PLUG
R
to4
47K
RloS
150
l/ 2
+12
V,l
D.C.
sw2
PLUG
Page 8
-8-
=
IJ] F
>a
a.7
OX
F>
s)
Page 9
VOTTAGE CHARI
The Voltage
You
should be
IC
No.I
PIN
Channel
1
2
3
4
5
6
7
8
9
10
1l
t2
l3
t4
No.
I selected.
Chart
familiar
1.4
GND
r.45
GND
11.6
t2
t2
GND
x
x
x
x
x
x
may
used as an approximate
be
with the entire manual before attempting measurements.
INTEGRATED
23456
1.4
GND
r.45
0
10.5
ll
10.2
0
x
x
x
x
x
x
5.6
3.4
0
1.4
t.4
1.4
GND
GND
.15
1.5
NC
3.4
t2
6.2
guide
in following circuit operation or locating a defective stag