as
near to the vehicle-body side
as
possible.
B)
Mount one-piax transceivers under the
dash or on the transmission hump. where they
do not interfere with vehicle controls or
passenger movement.
Antenna Installation
A)
Use
a permanently mounted antenna
located in the center of the roof or rear-deck
lid. Keep glass-mounted antennas as high
as
possible in the center of the rear window or
windshield. If a magnetic-mount antenna
must
be
used, carefully place it in a location
recommended for a permanently mounted
antenna. If a disguise-mount antenna is used,
shield the matching network from vehicle
electronics and wiring or mount the matching
network
in
an
area com~letelv clear of vehicle
-
-
electronics and wiring.
B) Radio-frequency energy affects each
vehicle model and body style differently.
When dealing with an unfamiliar vehicle, use
a magnetic-mount antenna to check proposed
antenna locations for unwanted effects.
(Antenna location is a major factor in these
effects.)
Antenna-Cable Routing
A) Always use high-quality coaxial cable
(at least
95%
shield coverage), and route it
away from the Engine Control Module and
other electronics modules.
B)
Do
not route feed line next to any
vehicle wiring.
Antenna Tuning
A) It is important to properly match the
antenna so that reflected power is kept to a
minimum (keep SWR less than 2:l).
Radio Wiring and Connection Locations
A) Transceiver power leads:
Power connections, including the ground,
should be made directly to the battery (or to
the jump-start block on vehicles
so
equipped).
Transceiver power leads should be no.
10
AWG or larger, installed
as
a twisted pair if
possible. The ground lead should not be
attached to the body at any point. Place
appropriate fuses,
as
near the battery as pos-
sible, in both positive and ground leads. (A
fuse in the transceiver ground lead prevents
possible transceiver damage should the
battery-to-engine-block ground be discon-
nected.)
Where ignition-switch control of dc power
is desired for one-piece transceivers, install a
12-V power contactor in the transceiver
positive lead. Install the contactor near the
vehicle battery, and drive the contactor coil
through an appropriate fuse from
an
available
accessory or ignition circuit that is not
powered during cranking. The contactor-coil
ground should return directly to the negative
battery terminal.
B) Handset or Control-Unit Battery and
Ground:
Any ground lead from a handset or con-
trol unit should return directfy to the negative
battery terminal. The positive lead of a
handset or control unit should
be
connected
directly to the positive battery terminal. Fuse
the handset or control unit power leads
separately from the transceiver power leads.
If the radio dc power must
be
controlled with
the ignition switch, the handset or control-unit
positive lead may
be
connected, through an
appropriate fuse, to an available accessory or
ignition circuit not powered during cranking.
C)
Cometions for multiple transceivers
and receivers:
If multiple transceivers or receivm
are
installed in the vehicle, install heavy power
conductors to the
trunk
or dash and
taminate
them
in covered,
insdated
bus
bats.
Connect
all radio power leads to the bus bars. (This
makes a neater installation and reduces the
number of wires running under the hood.)
Wire
Routing
A) Bring radio power
leads
inio the
passenger compartment through a grommet
in the driver's side of the fuewall. For trunk-
FWSH!
VCR
CURES
TVI!
0
HaeisatiponthewofaYHSvidcorepe
recorder. I live in the weak-reception
area
of
several
Lm
Angela television stations.
Whcn
the
signals
from thosc stations are very weak,
my
7-MHz
amateur transmissions produce
a
light cross-hatch pattan on Channel 5. I have
found that the interference
is
dimhated when
the received TV signal
is
passed through my
operating VCR. I do not know the gain of
the VCR front end, but it seems significant.
-K.
C. Jones. WWB, Hemet, California
mounted transceivers, continue the cables
L~C
TVI
along the driver's-side door sill(s), under the
rear seat, and into the
trunk
through the rear
I
live
in
a
small am4nt buildins at a
bulkhead. If the battery
is
located on the
Summer
area.
During the colder half
passenger side, power leads should cross the
the years
I
am
the
occupant
and
have
vehicle in front of the engine. Maintain as
TV1
worries-
As
warm
weather
ap
much distance as possible between radio
pr-hes, how-, the other apartments
start
power leads and vehicle electronic modules
fang
up-
Three
tenants have hand-~e+~own
and wiring. TV sets with poor antennas that are
B) For poll= vehicles, route radio power
particularly smtible to TVI- (MY own
leads in the conduit provided
the option
is
free of
TVi
even
when I use my amplifier.
package.
Thus, my station emissions are clean. That
doesn't
cut
any ice with the neighbors,
Troubleshooting
however, who want to see their programs.)
A) Should vehicle problems dewlop
For my Part, it
is
good practice to keep my
following installation, the source of the
neighbors happy,
So,
do I go QRT during
problem should
be
determined prior
to
further
TV-viewing hours? Not on your life!
I
have
vehicle operation.
set up a
TV
detector to determine when the
B) Possible causes of vehicle problems
are
watching TV.
include:
If you live in an apartment building,
1)
power
COMC!C~~O~~
to points other
perhaps
YOU
have noticed that your
AM
than the battery.
broadcast receiver is little better than useless
2) Antenna location.
when your (or your neighbor's) TV
is
on.
3) Transceiver wiring 10C8ted too
This is the result of interference from the
to vehicle electronic modules
or
wiring.
TV hori~ontal-sweep oscillator, and it is
4)
Poor shielding or poor connections
in
especially prevalent near the low end of
the antenna feed line.
the AM-broadcast dial. Such interference is
much worse on longwave frequencies (150-
Contact and Feedback
300
kHz).
AU
I do is tune my receiver near
Milford, Michigan
48042-
MORE
ON
THE
BALANCED
GRID
CIRCUIT
FOR
THE
SB-24M
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