Page 1
Mobile Gain Antennas
890-960 MHz
Models RRA-4935/RRA-4936
Installation
See Table 1 for recommended antenna location for various vehicles. Theinstallationprocedure which follows
is for a typical passenger car. The procedure may vary
slightly with the type of vehicle on which the antenna
is to be installed. Generally speaking, however, the
procedures outlined are of a "universal" nature.
CAUTION
Observe the safety precautions given in
this instruction manual. Never adjust
antenna whip length while the radio is
being keyed.
Figure 1.
Introduction
The mobile rooftop antenna is supplied with a coaxial
lead-in cable and a connector. In the completed installation, the cable is concealed between the headlining
and the roof of the vehicle, with a minimum disturbance to the headlining and the upholstery. Figure 11
provides a pictorial drawing of the disassembled
antenna complete with component part numbers.
Figure 1 shows an antenna assembled.
This antenna is factory tuned for 835 MHz.
NOTE
The antenna should be mounted on a flat
metal roof of .020 to .040 inch thickness.
First, select a location for the antenna as near the center
of the roofaspossible(seeStep 1 of the installation procedure following).
IMPORTANT
When installing the lead-in cable, the
cable should not be shortened.
The headlining may be probed with the fingers to
make sure that all points of obstruction will be
avoided.
1. Drill a pilot hole at selected location then, drill
a 3/4-inch hole from the top (outside the vehicle only) with the Motorola 01-80382A25
holecutting saw (or equivalent) until it bottoms. Clean the roof metal in a neat circle to
assure good contact with the mounting base
and its locking nut.
CAUTION
Advise the radio owner to unscrew the
upper antenna assembly at the knurled
section before entering an automatic car
wash to prevent damage to the antenna
or the roof of vehicle. When unscrewing
the antenna, be sure only the upper section, not the coupling nut is removed. If
the coupling nut should loosen,
retighten it securely against the mounting surface.
and Motorola are registered trademarks of Motorola, Inc. 68P81124E57-A
Copyright © 2000 Motorola, Inc. All Rights Reserved.
NOTE
In installations involving a double roof
with no dome light, a second 3/4-inch
hole must be drilled. However, a deepwell type of 3/4-inch hole saw (with pilot
drill bit) must be used to cut the second
(or bottom) roof section. This provides
access to the area where the coaxial cable
is routed, between the second roof section and headlining.
Page 2
Mobile Gain Antennas Installation
2. Drill the second 3/4-inch hole if required. Use
extreme caution, though, to prevent puncturing the head lining.
3. For proper seating of the mounting base and
locking nut, remove any burrs and/or foreign
matter from above and below the (top) 3/4inch mounting hole. This should be done for
at least 1/8-inch out from the hole edge. For
double roof construction vehicles (without
dome light), clear the second (or bottom) 3/4inch hole of any burrs also.
4. Determine the routing of the cable from the
antenna mounting base to the radio set; then
remove the molding and trim necessary to
facilitate pulling the cable through.
NOTE
To ensure ease of assembly, thread the
locking nut on the end of the mounting
base a couple of times before installing.
This removes any burrs that may be
present.
NOTE
Refer to Figure 2. Be sure to apply a generous amount of silicone grease (supplied) to the inner and outer threads of
the locking nut. In addition, be sure there
is some silicone grease applied to the
rubber "O" ring washer and the groove in
the locking nut in which it is seated.
5. Refer to Figure 3. Insert the end of the coaxial
cable into the mounting hole as shown; then
route the cable between the roof and headlining to the radio set.
NOTE
If difficulty is experienced with cable
routing, use an electrician's fishtape to
perform Step 5.
Figure 3.
6. Refer to Figure 4. Insert the mounting base
into the mounting hole as shown, tilted
slightly. Be sure that all of the cable has been
pulled through to the radio set. The threaded
portion of the mounting base will not fall
through the mounting hole.
IMPORTANT
In double roof vehicles, which have no
dome light, DO NOT attempt to secure
the base mount to both roof layers.
Secure it to the top, outer roof layer only.
Figure 4. Inserting the Mount Base
7. Refer to Figure 5. While holding the mounting
base down, thread the locking nut onto it.
When the nut is well onto the mounting base,
pull up on the entire assembly as shown in
Figure 6. Make sure the mounting base is centered in the hole, and seated properly with
both shoulders inside the mounting hole. Use
a 15/16-inch open-end wrench to tighten the
locking nut until it bottoms firmly against the
roof top.
Figure 2. Parts Identification
2 68P81124E57-A June, 2000
IMPORTANT
Refer to Figure 11. If the mounting base
should slip or rotate for any reason while
tightening, insert the tips of a long-nose
pliers or a spanner wrench into the two
holes on top of the mounting base. Apply
enough force to prevent slippage until
the locking nut is tight. The locking nut
must come in contact with the vehicle
roof to ensure the proper antenna radiation pattern. This can only be accomplished when the rubber "O" ring washer
is fully compressed.
Page 3
Installation MobileGain Antennas
Figure 6.Figure 5.
Figure 7. DoubleRoof (with DomeLight) Installation Figure 8. Double Roof (No Dome Light) Installation
NOTE
Figure 7 shows how the base mount
should be installed in a vehicle with double roof construction and a dome light
Figure 8 shows how the base mount
should be installed in a vehicle with double roof construction and no dome light.
Single roof installations will be similar to
Figure 7 except there is no second roof
layer present.
8. Refer to Figure 9. Slide the metal cap (coupling nut) over the antenna rod assembly until
it is in place over the plastic insulator of the
whip assembly. Put the whip assembly in
place over the locking nut and secure the
metal cap to the external threads of the locking nut. With the antenna rod in a perfectly
vertical position, tighten the metal cap by hand
as tight as possible. Then, with 10" adjustable
wrench or a 1" open end wrench, tighten no
more than an additional 1/2-turn.
9. Replace the headlining and dome light if
removed.
Figure 9.
June, 2000 68P81124E57-A 3
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Mobile Gain Antennas Connector Installation (Mini-UHF)
Figure 10. Crimp Tool
Connector Installation (Mini-UHF)
Use Motorola hand tool part #66-80388A26. Refer to
Figure 10. A deluxe rachet type tool is available; order
part #66-80334B40.
1. Slip the ferrule and collar onto the cable. Refer
to Figure 12.
2. Prepare the cable to strip dimensions per
Figure 13 which is also marked on the handtool.
4 68P81124E57-A June, 2000
Figure 11. Model shown is a complete antenna RRA-4935
NOTE
RRA-4936 is a magnetic mount
antenna. It is comprised of antenna
only P/N 01-80356A96, coupling nut
P/N 58-83882B01 and magnetic mount
P/N 01-80355A80. The antenna must
be located at the center of the roof.
3. Insert the stripped cable into the plug body
until the conductor is exposed (front end) and
Page 5
Antenna Test/Fine Tuning MobileGain Antennas
Plug Assembly Procedure
Figure 13.
Model Chart
RRA-4936A 3 dB Gain Antenna, Magnetic Mount 12’
RG58A/U Cable, Mini UHF Connector
Mounting Options
01-80355A80 Magnetic Mount 12’ RG58A/U Cable,
Mini UHF Connector
NOTE
The antenna must be located at the center of the roof.
Figure 12.
the dielectric bottoms inside the body. Refer to
Figure 12.
4. Crimp the center contact using the proper
crimp section of the tool. Refer to Figure 10
marked “CENTER CONTACT”.
5. Push the collar forward onto the plug assembly. Fit the cable braid over the support sleeve
of the connector. Refer to Figure 12.
6. Push the ferrule over the braid until the flange
butts against the connector body. Refer to
Figure 12. Using the correct crimp area of the
tool, crimp the ferrule close to the plug body.
See Figure 10 crimp location "C". Crimp the
ferrule a second time close to the cable end,
using the “C” crimp area of the tool.
7. The protruding center conductor should be
trimmed flush with the end of the center contact.
Antenna Test/Fine Tuning
This antenna is factory tuned for 902 MHz.
01-80355A88 Trunk Lip Mount 17’ RG58A/U Cable,
Mini UHF Connector
NOTE
Not recommended for transmitters with
power outputs of 7 W or greater.
Motorola Recommendations for
Mobile Antenna Location
Motorola recommends that mobile antennas be located
as follows. Refer to Table 1.
Antenna Location
Mobile Antenna Installation
Mobile Radio Operation and EME Exposure
Observe the following caution and electromagnetic
energy exposure (EME) statements when installing
antennas:
CAUTION
Use caution when installing antennas
with mobile radio equipment using
transmitter power of 7 W or greater.
Install antennas only on metal bodied
vehicles.
NOTE
For low-power mobile radios (less than
7 W) there are no antenna type or installation restrictions.
June, 2000 68P81124E57-A 5
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Mobile Gain Antennas Motorola Recommendations for Mobile Antenna Location
Table 1.
Standard metal passenger vehicles Center roof or center trunk lid
Vans, pickups, and other light trucks (metal roofs) Center roof
Heavy duty equipment with metal roofs (heavy duty trucks,
semi-tractors, heavy refuse trucks, cement mixer trucks)
Specialty vehicles (such as T-roofs, sun roofs, or convertibles) Center trunk lid – recommended only for transmitter output of
Other vehicles Contact your Motorola Field TechnicalRepresentative. Do not
Center cab roof
less than 7 W.
install closer than the distances shown in Table 2, for the relevant transmitter output power, from occupants or without
proper antenna ground plane.
Table 2. Rated Power and Distance
Rated Power of Vehicle-installed
Mobile Two-Way Radios
7 to 15 W 1 Foot (30.5cm)
16 to 50 W 2 Feet (61cm)
More than 50 W 3 Feet (91.5cm)
Minimum Distance from
Transmitting Antenna
To assure optimal radio performance and that human
exposure to radio frequency electromagnetic energy is
within the guidelines referenced in this document,
transmit only when people outside the vehicle are at
least the minimum distance away from a properly
installed, externally-mounted antenna.
Table 2 lists the minimum distance for several different
ranges of rated radio power.
Selecting an Antenna Site
1. Install the vehicle antenna external to the
vehicle and in accordance with the requirements contained in this manual.
2. The best mounting location for the antenna is
in the center of a large, flat conductive surface.
In almost all vehicles, mounting the antenna
in the center of the roof will satisfy these
requirements. A good alternative location is in
the center of the trunk lid. If you use the trunk
lid, ensure that the trunk lid is grounded by
connecting grounding straps between the
trunk lid and the vehicle chassis.
3. Ensure the antenna cable can be easily routed
to the radio. Ensure that the antenna cable is
routed separately and not in parallel to any
other vehicle wiring or mobile radio cable
wiring.
4. Check the antenna location for any electrical
interference.
NOTE
Any two metal pieces rubbing against
each other (such as seat springs, shift
levers, trunk and hood lids, exhaust pipes,
etc.) in close proximity to the antenna can
cause severe receiver interference.
5. If the vehicle is equipped with an electronic
anti-lock braking system (ABS), mount the
antenna at the center of the roof or trunk lid
and do not route the antenna cable near the
ABS Modulator Box. Mount the radio as far
away from the Modulator Box as physically
possible. This minimizes radio interference to
the modulator box from the radio.
6. Make sure the mobile radio antenna is
installed at least one foot (30.48cm) away from
any other antenna on the vehicle.
6 68P81124E57-A June, 2000
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