11.2 Antenna diversity
The 4600/A & 5600/A modems have two antenna connectors available, labeled RF-1 and RF-2.
•
RF-1 : This is the main antenna that is used for data transmission. It is mandatory
to have RF-1 connected to an antenna.
•
RF-2 : This is the diversity antenna, used to improve on the signal strength
obtained from RF-1. This antenna is not mandatory however it can improve
reception in some situations.
Diversity is a transmission technique that consists of using two separate antennas to achieve
the best cellular signal possible. The transmissions will be done using the antenna which has
the best reception. Diversity is particularly useful in mobile environments.
The diversity antenna should be placed with these recommendations in mind for optimal use:
•
The minimum distance between the main antenna and the diversity antenna
should be 9".
•
The recommended minimum distance between main antenna and the diversity
antenna is 18".
•
If it is possible to increase the distance between the two antennas, use increments
of 9", such as 27", 36", 45", etc.
11.3 GPS antenna
The 5200 & 5600/A modems have an additional SMA connector for the GPS antenna. The
selected GPS antenna must meet the following specifications:
•
Active antenna with 3.3 volts preamplifier
•
Nominal 50 Ohms impedance
•
Male SMA connector
•
Frequency band: 1575 MHz
When installing the GPS antenna, make sure it has line-of-sight with the sky. Then connect the
cable’s connector into the modem’s GPS connector by screwing it in tightly by hand.
To test the installation, look at the GPS LED at the front of the modem. It will start flashing
once a fix has been acquired. After the antenna is installed, allow a couple of minutes before a
fix is acquired, as it can take up to three minutes for the modem to synchronize with the
available GPS satellites.
