OGi Modem - Hardware Guide
T401, Version .15 30 © ORBCOMM Proprietary
4.3.1 Typical Integration
The modem is intended to be used in a larger system. The system must provide adequate
power (low noise and relatively high current) and must possess an electrical signaling
mechanism compatible with the modem. Ensure that the custom designed circuit board
does not create undesirable signals that can impact the performance of the modem. An
external antenna is required to complete the modem design.
Figure 21 Typical OEM Integrator Modem Design
4.3.2 Antenna Cable Guidelines
The OEM Integrator is responsible for designing a custom-made RF cable to connect
antenna and modem. The following recommendations provide some guidelines for RF
cable selection:
Application
Cable Type
Connector
Max. Total
Loss at
1.6 GHz
Cable
Example
Packaged/Remote
Antenna cable
RF Coaxial
50 Ω
MMCX male/SMA
male
1.5 dB
LMR195
Unpackaged
Antenna Cable
RF Coaxial
50 Ω
MMCX male/IPEX
plug male
0.5 dB
-
4.3.2.1 General Guidelines for Antenna Positioning
Antenna placement is important. When positioning the antenna consider EMI
performance of the integration product and visibility to the sky.
Depending on the EMI performance of the integration product, the satellite antenna may
need to be paced a distance away from the integration product.
The antenna must be positioned such that it has a good view of the sky and there is no
metal/circuit board nearby to interfere with or block the antenna.
4.3.3 Host Shielding
In a typical integration, the modem is controlled by microcontroller.
The microcontroller and supporting circuitry, such as memory, high speed data/address
bus, clock references and power supply sources are normally noisy and could potentially
