Installation Manual

120 20110-141 Gemini
PD
Installation Guide
7
2.5 Antenna
To meet the FCC’s RF Exposure Guide-
lines, the main transmitter antenna must be
vehicle-mounted to provide a separation
distance of 50 cm or more from all persons
and the antenna gain must not exceed 5dB
to satisfy RF exposure requirements.
2.5.1 Recommended tools and
supplies
• circle cutter
• hole saw or
• socket punch for antenna
• Mini-UHF Crimp tool
2.5.2 Planning
Referring to Figure 4, Gemini
PD
commonly
uses three separate antennas:
• “T” - Main transceiver -
Constraints are Maximum Permissive
Exposure (“MPE” on the drawing) lim-
its of 50 cm (as per see section 2.5
above) and omni-directional factors
• “R” - Auxiliary receiver –
Constraints are the receiver spacing of
at least 5/8 λ (wavelength) from trans-
ceiver antenna and omni-directional re-
quirements
• “G” - Global Positioning System
(GPS)*
Constraints are TX spacing of at least
24-in/60.96 cm from all transmitting
antennas and a clear view of the sky.
For the optimum antenna spacing at the fre-
quency you are using, consult System Engi-
neering.
For installation of ground-plane dependent
antennas, the center of the metal surface
used for mounting is preferable for best
omni-directional pattern.
For ground-plane independent antennas,
installation may be close to the edges of the
surface.
*
The Gemini
PD
Lite model has no GPS.
Figure 4 - Antenna spacing
Install the antennas in one of the following
positions:
- Most preferred for all antennas: center-
line of roof. For transmitter antenna, it
is the ONLY acceptable position.
- Less preferred for receiver antenna:
trunk lid, providing distance to trans-
mitting antenna is respected whether lid
is opened or closed.
- Much less preferred, but permissible for
receiver antenna: left or right rear fend-
ers, just in back of rear window
- Least preferred, but permissible for re-
ceiver antenna: left or right front fend-
ers, ahead of windshield
Note:
Proximity to other vehicle-mounted
antennas may cause mutual inter-
ference especially at higher fre-
quencies.
G
MPE
≥
≥≥
≥
5/8
λ
λλ
λ
(UHF: 18"/46cm
800MHz: 9
"
/23cm)
R
T
50cm
19.7in.
≥
≥≥
≥
24in.